From 161a582bd1d8681095f158d11bc679a58f1d026b Mon Sep 17 00:00:00 2001
From: Tom Rix <trix@redhat.com>
Date: Mon, 11 Jan 2021 14:09:04 -0800
Subject: [PATCH 01/41] USB: serial: mos7720: improve OOM-handling in
 read_mos_reg()

clang static analysis reports this problem

mos7720.c:352:2: warning: Undefined or garbage value returned to caller
        return d;
        ^~~~~~~~

In the parport_mos7715_read_data()'s call to read_mos_reg(), 'd' is
only set after the alloc block.

	buf = kmalloc(1, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

Although the problem is reported in parport_most7715_read_data(),
none of the callee's of read_mos_reg() check the return status.

Make sure to clear the return-value buffer also on allocation failures.

Fixes: 0d130367abf5 ("USB: serial: mos7720: fix control-message error handling")
Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20210111220904.1035957-1-trix@redhat.com
[ johan: only clear the buffer on errors, amend commit message ]
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/mos7720.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index 41ee2984a0df..ed347a6d50ba 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -215,8 +215,10 @@ static int read_mos_reg(struct usb_serial *serial, unsigned int serial_portnum,
 	int status;
 
 	buf = kmalloc(1, GFP_KERNEL);
-	if (!buf)
+	if (!buf) {
+		*data = 0;
 		return -ENOMEM;
+	}
 
 	status = usb_control_msg(usbdev, pipe, request, requesttype, value,
 				     index, buf, 1, MOS_WDR_TIMEOUT);

From 979d9cbe75b922ab1695b8ad5576115774f72e62 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 11 Jan 2021 18:00:19 +0100
Subject: [PATCH 02/41] USB: serial: pl2303: fix line-speed handling on newer
 chips

The latest chip family (HXN) apparently does not support setting the
line speed using divisors and instead needs to use the direct encoding
scheme for all rates.

This specifically enables 50, 110, 134, 200 bps and other rates not
supported by the original chip type.

Fixes: ebd09f1cd417 ("USB: serial: pl2303: add support for PL2303HXN")
Cc: stable@vger.kernel.org      # 5.5
Cc: Charles Yeh <charlesyeh522@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/pl2303.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index be8067017eaa..29dda60e3bcd 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -183,6 +183,7 @@ struct pl2303_type_data {
 	speed_t max_baud_rate;
 	unsigned long quirks;
 	unsigned int no_autoxonxoff:1;
+	unsigned int no_divisors:1;
 };
 
 struct pl2303_serial_private {
@@ -209,6 +210,7 @@ static const struct pl2303_type_data pl2303_type_data[TYPE_COUNT] = {
 	},
 	[TYPE_HXN] = {
 		.max_baud_rate		= 12000000,
+		.no_divisors		= true,
 	},
 };
 
@@ -571,8 +573,12 @@ static void pl2303_encode_baud_rate(struct tty_struct *tty,
 		baud = min_t(speed_t, baud, spriv->type->max_baud_rate);
 	/*
 	 * Use direct method for supported baud rates, otherwise use divisors.
+	 * Newer chip types do not support divisor encoding.
 	 */
-	baud_sup = pl2303_get_supported_baud_rate(baud);
+	if (spriv->type->no_divisors)
+		baud_sup = baud;
+	else
+		baud_sup = pl2303_get_supported_baud_rate(baud);
 
 	if (baud == baud_sup)
 		baud = pl2303_encode_baud_rate_direct(buf, baud);

From 7748feffcd80f3ee25dae5e6acd3cf90e8e838d8 Mon Sep 17 00:00:00 2001
From: Wang Sheng Long <shenglong.wang.ext@siemens.com>
Date: Mon, 18 Jan 2021 12:13:26 +0100
Subject: [PATCH 03/41] USB: serial: cp210x: add support for software flow
 control

When data is transmitted between two serial ports, the phenomenon of
data loss often occurs. The two kinds of flow control commonly used in
serial communication are hardware flow control and software flow
control.

In serial communication, If you only use RX/TX/GND Pins, you can't do
hardware flow. So we often used software flow control and prevent data
loss. The user sets the software flow control through the application
program, and the application program sets the software flow control mode
for the serial port chip through the driver.

For the cp210 serial port chip, its driver lacks the software flow
control setting code, so the user cannot set the software flow control
function through the application program. This adds the missing software
flow control.

Signed-off-by: Wang Sheng Long <shenglong.wang.ext@siemens.com>
Link: https://lore.kernel.org/r/20210104094502.3942-1-china_shenglong@163.com
[ johan: rework properly on top of recent termios changes ]
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/cp210x.c | 67 +++++++++++++++++++++++++++++++++++--
 1 file changed, 65 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index fbb10dfc56e3..5bd14770065b 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -377,6 +377,16 @@ static struct usb_serial_driver * const serial_drivers[] = {
 #define CONTROL_WRITE_DTR	0x0100
 #define CONTROL_WRITE_RTS	0x0200
 
+/* CP210X_(GET|SET)_CHARS */
+struct cp210x_special_chars {
+	u8	bEofChar;
+	u8	bErrorChar;
+	u8	bBreakChar;
+	u8	bEventChar;
+	u8	bXonChar;
+	u8	bXoffChar;
+};
+
 /* CP210X_VENDOR_SPECIFIC values */
 #define CP210X_READ_2NCONFIG	0x000E
 #define CP210X_READ_LATCH	0x00C2
@@ -1074,11 +1084,38 @@ static void cp210x_disable_event_mode(struct usb_serial_port *port)
 	port_priv->event_mode = false;
 }
 
+static int cp210x_set_chars(struct usb_serial_port *port,
+		struct cp210x_special_chars *chars)
+{
+	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
+	struct usb_serial *serial = port->serial;
+	void *dmabuf;
+	int result;
+
+	dmabuf = kmemdup(chars, sizeof(*chars), GFP_KERNEL);
+	if (!dmabuf)
+		return -ENOMEM;
+
+	result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
+				CP210X_SET_CHARS, REQTYPE_HOST_TO_INTERFACE, 0,
+				port_priv->bInterfaceNumber,
+				dmabuf, sizeof(*chars), USB_CTRL_SET_TIMEOUT);
+
+	kfree(dmabuf);
+
+	if (result < 0) {
+		dev_err(&port->dev, "failed to set special chars: %d\n", result);
+		return result;
+	}
+
+	return 0;
+}
+
 static bool cp210x_termios_change(const struct ktermios *a, const struct ktermios *b)
 {
 	bool iflag_change;
 
-	iflag_change = ((a->c_iflag ^ b->c_iflag) & INPCK);
+	iflag_change = ((a->c_iflag ^ b->c_iflag) & (INPCK | IXON | IXOFF));
 
 	return tty_termios_hw_change(a, b) || iflag_change;
 }
@@ -1086,13 +1123,29 @@ static bool cp210x_termios_change(const struct ktermios *a, const struct ktermio
 static void cp210x_set_flow_control(struct tty_struct *tty,
 		struct usb_serial_port *port, struct ktermios *old_termios)
 {
+	struct cp210x_special_chars chars;
 	struct cp210x_flow_ctl flow_ctl;
 	u32 flow_repl;
 	u32 ctl_hs;
 	int ret;
 
-	if (old_termios && C_CRTSCTS(tty) == (old_termios->c_cflag & CRTSCTS))
+	if (old_termios &&
+			C_CRTSCTS(tty) == (old_termios->c_cflag & CRTSCTS) &&
+			I_IXON(tty) == (old_termios->c_iflag & IXON) &&
+			I_IXOFF(tty) == (old_termios->c_iflag & IXOFF)) {
 		return;
+	}
+
+	if (I_IXON(tty) || I_IXOFF(tty)) {
+		memset(&chars, 0, sizeof(chars));
+
+		chars.bXonChar = START_CHAR(tty);
+		chars.bXoffChar = STOP_CHAR(tty);
+
+		ret = cp210x_set_chars(port, &chars);
+		if (ret)
+			return;
+	}
 
 	ret = cp210x_read_reg_block(port, CP210X_GET_FLOW, &flow_ctl,
 			sizeof(flow_ctl));
@@ -1118,6 +1171,16 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
 		flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_ACTIVE);
 	}
 
+	if (I_IXOFF(tty))
+		flow_repl |= CP210X_SERIAL_AUTO_RECEIVE;
+	else
+		flow_repl &= ~CP210X_SERIAL_AUTO_RECEIVE;
+
+	if (I_IXON(tty))
+		flow_repl |= CP210X_SERIAL_AUTO_TRANSMIT;
+	else
+		flow_repl &= ~CP210X_SERIAL_AUTO_TRANSMIT;
+
 	dev_dbg(&port->dev, "%s - ulControlHandshake=0x%08x, ulFlowReplace=0x%08x\n",
 			__func__, ctl_hs, flow_repl);
 

From f61309d9c96a308465bec9d2e5206da265b075a0 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 18 Jan 2021 12:13:27 +0100
Subject: [PATCH 04/41] USB: serial: cp210x: set IXOFF thresholds

At least CP2102 requires the XON/XOFF limits to be initialised in order
for software input flow control (IXOFF) to work. Specifically, XOFF is
never sent if the XOFF limit is left at its default value of zero.

Set the limits so that input is throttled when the FIFO free level drops
below 128 bytes and restarted when the FIFO fill level drops below 128
bytes.

Note that the threshold values have been chosen so that they can be used
also with CP2105 which has the smallest FIFO of the currently supported
device types (288 byte for the SCI port). If needed the limits can be
made device specific later.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/cp210x.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 5bd14770065b..ee0139eb6636 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -1181,6 +1181,9 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
 	else
 		flow_repl &= ~CP210X_SERIAL_AUTO_TRANSMIT;
 
+	flow_ctl.ulXonLimit = cpu_to_le32(128);
+	flow_ctl.ulXoffLimit = cpu_to_le32(128);
+
 	dev_dbg(&port->dev, "%s - ulControlHandshake=0x%08x, ulFlowReplace=0x%08x\n",
 			__func__, ctl_hs, flow_repl);
 

From 03f32d7cb51b62f6cc7fd884d6978fe1a6ad3f8d Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 18 Jan 2021 12:13:28 +0100
Subject: [PATCH 05/41] USB: serial: cp210x: update control-characters on every
 change

Update the XON/XOFF control characters also when no other flow-control
flag has changed and software flow control is enabled.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/cp210x.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index ee0139eb6636..4f90573c0d2b 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -1113,11 +1113,13 @@ static int cp210x_set_chars(struct usb_serial_port *port,
 
 static bool cp210x_termios_change(const struct ktermios *a, const struct ktermios *b)
 {
-	bool iflag_change;
+	bool iflag_change, cc_change;
 
 	iflag_change = ((a->c_iflag ^ b->c_iflag) & (INPCK | IXON | IXOFF));
+	cc_change = a->c_cc[VSTART] != b->c_cc[VSTART] ||
+			a->c_cc[VSTOP] != b->c_cc[VSTOP];
 
-	return tty_termios_hw_change(a, b) || iflag_change;
+	return tty_termios_hw_change(a, b) || iflag_change || cc_change;
 }
 
 static void cp210x_set_flow_control(struct tty_struct *tty,
@@ -1132,7 +1134,9 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
 	if (old_termios &&
 			C_CRTSCTS(tty) == (old_termios->c_cflag & CRTSCTS) &&
 			I_IXON(tty) == (old_termios->c_iflag & IXON) &&
-			I_IXOFF(tty) == (old_termios->c_iflag & IXOFF)) {
+			I_IXOFF(tty) == (old_termios->c_iflag & IXOFF) &&
+			START_CHAR(tty) == old_termios->c_cc[VSTART] &&
+			STOP_CHAR(tty) == old_termios->c_cc[VSTOP]) {
 		return;
 	}
 

From dc5338fc64b23e37b000d1a29b88dc8209acebf9 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 18 Jan 2021 12:13:29 +0100
Subject: [PATCH 06/41] USB: serial: cp210x: drop short control-transfer checks

There's no need to check for short control transfers when sending data
so remove the redundant sanity checks.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/cp210x.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 4f90573c0d2b..360398665c17 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -674,16 +674,13 @@ static int cp210x_write_reg_block(struct usb_serial_port *port, u8 req,
 
 	kfree(dmabuf);
 
-	if (result == bufsize) {
-		result = 0;
-	} else {
+	if (result < 0) {
 		dev_err(&port->dev, "failed set req 0x%x size %d status: %d\n",
 				req, bufsize, result);
-		if (result >= 0)
-			result = -EIO;
+		return result;
 	}
 
-	return result;
+	return 0;
 }
 
 /*
@@ -720,17 +717,14 @@ static int cp210x_write_vendor_block(struct usb_serial *serial, u8 type,
 
 	kfree(dmabuf);
 
-	if (result == bufsize) {
-		result = 0;
-	} else {
+	if (result < 0) {
 		dev_err(&serial->interface->dev,
 			"failed to set vendor val 0x%04x size %d: %d\n", val,
 			bufsize, result);
-		if (result >= 0)
-			result = -EIO;
+		return result;
 	}
 
-	return result;
+	return 0;
 }
 #endif
 

From 4c0a84cb09045b18fc4d6e01238fa946ba39dc74 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 18 Jan 2021 12:13:30 +0100
Subject: [PATCH 07/41] USB: serial: cp210x: drop unused includes

Drop include directives that are no longer used.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/cp210x.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 360398665c17..0d0fc1f9e99b 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -16,13 +16,10 @@
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
 #include <linux/module.h>
-#include <linux/moduleparam.h>
 #include <linux/usb.h>
-#include <linux/uaccess.h>
 #include <linux/usb/serial.h>
 #include <linux/gpio/driver.h>
 #include <linux/bitops.h>
-#include <linux/mutex.h>
 
 #define DRIVER_DESC "Silicon Labs CP210x RS232 serial adaptor driver"
 

From 90fa41ee4a671d678fcd2c3f0ffdcaa10a1b080b Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 18 Jan 2021 12:13:31 +0100
Subject: [PATCH 08/41] USB: serial: cp210x: add copyright notice

Add a copyright notice for myself.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/cp210x.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 0d0fc1f9e99b..d813a052738f 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -3,6 +3,7 @@
  * Silicon Laboratories CP210x USB to RS232 serial adaptor driver
  *
  * Copyright (C) 2005 Craig Shelley (craig@microtron.org.uk)
+ * Copyright (C) 2010-2021 Johan Hovold (johan@kernel.org)
  *
  * Support to set flow control line levels using TIOCMGET and TIOCMSET
  * thanks to Karl Hiramoto karl@hiramoto.org. RTSCTS hardware flow

From f7de9b64265faafe96c2533ddfcc1ad7b2e8080d Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 18 Jan 2021 12:14:21 +0100
Subject: [PATCH 09/41] USB: serial: mxuport: drop short control-transfer check

There's no need to check for short control transfers when sending data
so remove the redundant sanity check.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/mxuport.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/usb/serial/mxuport.c b/drivers/usb/serial/mxuport.c
index 5d38c2a0f590..eb45a9b0005c 100644
--- a/drivers/usb/serial/mxuport.c
+++ b/drivers/usb/serial/mxuport.c
@@ -261,13 +261,6 @@ static int mxuport_send_ctrl_data_urb(struct usb_serial *serial,
 		return status;
 	}
 
-	if (status != size) {
-		dev_err(&serial->interface->dev,
-			"%s - short write (%d / %zd)\n",
-			__func__, status, size);
-		return -EIO;
-	}
-
 	return 0;
 }
 

From 2dc0e7c37549038444a5202e028ff5625c764012 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 18 Jan 2021 12:14:22 +0100
Subject: [PATCH 10/41] USB: serial: upd78f0730: drop short control-transfer
 check

There's no need to check for short control transfers when sending data
so remove the redundant sanity check.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/upd78f0730.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/usb/serial/upd78f0730.c b/drivers/usb/serial/upd78f0730.c
index 0a2268c479af..1ca9c1881621 100644
--- a/drivers/usb/serial/upd78f0730.c
+++ b/drivers/usb/serial/upd78f0730.c
@@ -145,14 +145,11 @@ static int upd78f0730_send_ctl(struct usb_serial_port *port,
 
 	kfree(buf);
 
-	if (res != size) {
+	if (res < 0) {
 		struct device *dev = &port->dev;
 
 		dev_err(dev, "failed to send control request %02x: %d\n",
 			*(u8 *)data, res);
-		/* The maximum expected length of a transfer is 6 bytes */
-		if (res >= 0)
-			res = -EIO;
 
 		return res;
 	}

From 66db94786e94fe2c060ab31bd8ed0308810ab610 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 18 Jan 2021 12:14:23 +0100
Subject: [PATCH 11/41] USB: serial: io_ti: drop short control-transfer check

There's no need to check for short control transfers when sending data
so remove the redundant sanity check.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/io_ti.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index c327d4cf7928..0c4062698603 100644
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -283,11 +283,7 @@ static int ti_vsend_sync(struct usb_device *dev, u8 request, u16 value,
 			value, index, data, size, timeout);
 	if (status < 0)
 		return status;
-	if (status != size) {
-		dev_dbg(&dev->dev, "%s - wanted to write %d, but only wrote %d\n",
-			__func__, size, status);
-		return -ECOMM;
-	}
+
 	return 0;
 }
 

From 0765590f91a2b88dc3b946b954c47f774a051636 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 18 Jan 2021 12:14:24 +0100
Subject: [PATCH 12/41] USB: serial: io_ti: fix a debug-message copy-paste
 error

Fix a copy-paste error in the ti_vread_sync() debug message.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/io_ti.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index 0c4062698603..0bbfa47e04b7 100644
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -266,7 +266,7 @@ static int ti_vread_sync(struct usb_device *dev, __u8 request,
 	if (status < 0)
 		return status;
 	if (status != size) {
-		dev_dbg(&dev->dev, "%s - wanted to write %d, but only wrote %d\n",
+		dev_dbg(&dev->dev, "%s - wanted to read %d, but only read %d\n",
 			__func__, size, status);
 		return -ECOMM;
 	}

From 18d8fe614fad9e82ad45b6984f8c6cf733d38bc3 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 18 Jan 2021 12:14:25 +0100
Subject: [PATCH 13/41] USB: serial: f81232: drop short control-transfer checks

There's no need to check for short control transfers when sending data
so remove the redundant sanity checks.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/f81232.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
index 0c7eacc630e0..6a8f39147d8e 100644
--- a/drivers/usb/serial/f81232.c
+++ b/drivers/usb/serial/f81232.c
@@ -192,13 +192,9 @@ static int f81232_set_register(struct usb_serial_port *port, u16 reg, u8 val)
 				tmp,
 				sizeof(val),
 				USB_CTRL_SET_TIMEOUT);
-	if (status != sizeof(val)) {
+	if (status < 0) {
 		dev_err(&port->dev, "%s failed status: %d\n", __func__, status);
-
-		if (status < 0)
-			status = usb_translate_errors(status);
-		else
-			status = -EIO;
+		status = usb_translate_errors(status);
 	} else {
 		status = 0;
 	}
@@ -886,10 +882,6 @@ static int f81534a_ctrl_set_register(struct usb_interface *intf, u16 reg,
 			status = usb_translate_errors(status);
 			if (status == -EIO)
 				continue;
-		} else if (status != size) {
-			/* Retry on short transfers */
-			status = -EIO;
-			continue;
 		} else {
 			status = 0;
 		}

From cfb0fde7a7fab4509fdb4f7ab72d5fd7157c0aa0 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 18 Jan 2021 12:14:26 +0100
Subject: [PATCH 14/41] USB: serial: f81534: drop short control-transfer check

There's no need to check for short control transfers when sending data
so remove the redundant sanity check.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/f81534.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/usb/serial/f81534.c b/drivers/usb/serial/f81534.c
index 5661fd03e545..dd7e55e822ef 100644
--- a/drivers/usb/serial/f81534.c
+++ b/drivers/usb/serial/f81534.c
@@ -235,11 +235,9 @@ static int f81534_set_register(struct usb_serial *serial, u16 reg, u8 data)
 					 USB_TYPE_VENDOR | USB_DIR_OUT,
 					 reg, 0, tmp, sizeof(u8),
 					 F81534_USB_TIMEOUT);
-		if (status > 0) {
+		if (status == sizeof(u8)) {
 			status = 0;
 			break;
-		} else if (status == 0) {
-			status = -EIO;
 		}
 	}
 

From c2d405aa86b451f197ee95cb08887130b86b765e Mon Sep 17 00:00:00 2001
From: Manivannan Sadhasivam <mani@kernel.org>
Date: Sun, 22 Nov 2020 22:38:20 +0530
Subject: [PATCH 15/41] USB: serial: add MaxLinear/Exar USB to Serial driver

Add support for MaxLinear/Exar USB to Serial converters. This driver
only supports XR21V141X series but it can be extended to other series
from Exar as well in future.

This driver is inspired from the initial one submitted by Patong Yang:

https://lore.kernel.org/r/20180404070634.nhspvmxcjwfgjkcv@advantechmxl-desktop

While the initial driver was a custom tty USB driver exposing whole
new serial interface ttyXRUSBn, this version is completely based on USB
serial core thus exposing the interfaces as ttyUSBn. This will avoid
the overhead of exposing a new USB serial interface which the userspace
tools are unaware of.

The Exar XR21V141X can be used in either ACM mode using the cdc-acm
driver or in "custom driver" mode in which further features such as
hardware and software flow control, GPIO control and in-band line-status
reporting are available.

In ACM mode the device always enables RTS/CTS flow control, something
which could prevent transmission in case the CTS input isn't wired up
corrently.

A follow-on patch will prevent cdc_acm from binding whenever this driver
is enabled.

Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://lore.kernel.org/r/20201122170822.21715-2-mani@kernel.org
[ johan: fix some style nits, group related functions, drop unused
	 callbacks, and amend commit message; a few remaining
	 non-trivial issues will be fixed separately ]
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/Kconfig     |   9 +
 drivers/usb/serial/Makefile    |   1 +
 drivers/usb/serial/xr_serial.c | 595 +++++++++++++++++++++++++++++++++
 3 files changed, 605 insertions(+)
 create mode 100644 drivers/usb/serial/xr_serial.c

diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
index a21ff5ab6df9..de5c01257060 100644
--- a/drivers/usb/serial/Kconfig
+++ b/drivers/usb/serial/Kconfig
@@ -633,6 +633,15 @@ config USB_SERIAL_UPD78F0730
 	  To compile this driver as a module, choose M here: the
 	  module will be called upd78f0730.
 
+config USB_SERIAL_XR
+	tristate "USB MaxLinear/Exar USB to Serial driver"
+	help
+	  Say Y here if you want to use MaxLinear/Exar USB to Serial converter
+	  devices.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called xr_serial.
+
 config USB_SERIAL_DEBUG
 	tristate "USB Debugging Device"
 	help
diff --git a/drivers/usb/serial/Makefile b/drivers/usb/serial/Makefile
index 50c53aed787a..c7bb1a88173e 100644
--- a/drivers/usb/serial/Makefile
+++ b/drivers/usb/serial/Makefile
@@ -61,4 +61,5 @@ obj-$(CONFIG_USB_SERIAL_UPD78F0730)		+= upd78f0730.o
 obj-$(CONFIG_USB_SERIAL_VISOR)			+= visor.o
 obj-$(CONFIG_USB_SERIAL_WISHBONE)		+= wishbone-serial.o
 obj-$(CONFIG_USB_SERIAL_WHITEHEAT)		+= whiteheat.o
+obj-$(CONFIG_USB_SERIAL_XR)			+= xr_serial.o
 obj-$(CONFIG_USB_SERIAL_XSENS_MT)		+= xsens_mt.o
diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c
new file mode 100644
index 000000000000..bdb2df27b50b
--- /dev/null
+++ b/drivers/usb/serial/xr_serial.c
@@ -0,0 +1,595 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * MaxLinear/Exar USB to Serial driver
+ *
+ * Copyright (c) 2020 Manivannan Sadhasivam <mani@kernel.org>
+ *
+ * Based on the initial driver written by Patong Yang:
+ *
+ *   https://lore.kernel.org/r/20180404070634.nhspvmxcjwfgjkcv@advantechmxl-desktop
+ *
+ *   Copyright (c) 2018 Patong Yang <patong.mxl@gmail.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+
+struct xr_txrx_clk_mask {
+	u16 tx;
+	u16 rx0;
+	u16 rx1;
+};
+
+#define XR_INT_OSC_HZ			48000000U
+#define XR21V141X_MIN_SPEED		46U
+#define XR21V141X_MAX_SPEED		XR_INT_OSC_HZ
+
+/* USB Requests */
+#define XR21V141X_SET_REQ		0
+#define XR21V141X_GET_REQ		1
+
+#define XR21V141X_CLOCK_DIVISOR_0	0x04
+#define XR21V141X_CLOCK_DIVISOR_1	0x05
+#define XR21V141X_CLOCK_DIVISOR_2	0x06
+#define XR21V141X_TX_CLOCK_MASK_0	0x07
+#define XR21V141X_TX_CLOCK_MASK_1	0x08
+#define XR21V141X_RX_CLOCK_MASK_0	0x09
+#define XR21V141X_RX_CLOCK_MASK_1	0x0a
+
+/* XR21V141X register blocks */
+#define XR21V141X_UART_REG_BLOCK	0
+#define XR21V141X_UM_REG_BLOCK		4
+#define XR21V141X_UART_CUSTOM_BLOCK	0x66
+
+/* XR21V141X UART Manager Registers */
+#define XR21V141X_UM_FIFO_ENABLE_REG	0x10
+#define XR21V141X_UM_ENABLE_TX_FIFO	0x01
+#define XR21V141X_UM_ENABLE_RX_FIFO	0x02
+
+#define XR21V141X_UM_RX_FIFO_RESET	0x18
+#define XR21V141X_UM_TX_FIFO_RESET	0x1c
+
+#define XR21V141X_UART_ENABLE_TX	0x1
+#define XR21V141X_UART_ENABLE_RX	0x2
+
+#define XR21V141X_UART_MODE_RI		BIT(0)
+#define XR21V141X_UART_MODE_CD		BIT(1)
+#define XR21V141X_UART_MODE_DSR		BIT(2)
+#define XR21V141X_UART_MODE_DTR		BIT(3)
+#define XR21V141X_UART_MODE_CTS		BIT(4)
+#define XR21V141X_UART_MODE_RTS		BIT(5)
+
+#define XR21V141X_UART_BREAK_ON		0xff
+#define XR21V141X_UART_BREAK_OFF	0
+
+#define XR21V141X_UART_DATA_MASK	GENMASK(3, 0)
+#define XR21V141X_UART_DATA_7		0x7
+#define XR21V141X_UART_DATA_8		0x8
+
+#define XR21V141X_UART_PARITY_MASK	GENMASK(6, 4)
+#define XR21V141X_UART_PARITY_SHIFT	0x4
+#define XR21V141X_UART_PARITY_NONE	0x0
+#define XR21V141X_UART_PARITY_ODD	0x1
+#define XR21V141X_UART_PARITY_EVEN	0x2
+#define XR21V141X_UART_PARITY_MARK	0x3
+#define XR21V141X_UART_PARITY_SPACE	0x4
+
+#define XR21V141X_UART_STOP_MASK	BIT(7)
+#define XR21V141X_UART_STOP_SHIFT	0x7
+#define XR21V141X_UART_STOP_1		0x0
+#define XR21V141X_UART_STOP_2		0x1
+
+#define XR21V141X_UART_FLOW_MODE_NONE	0x0
+#define XR21V141X_UART_FLOW_MODE_HW	0x1
+#define XR21V141X_UART_FLOW_MODE_SW	0x2
+
+#define XR21V141X_UART_MODE_GPIO_MASK	GENMASK(2, 0)
+#define XR21V141X_UART_MODE_RTS_CTS	0x1
+#define XR21V141X_UART_MODE_DTR_DSR	0x2
+#define XR21V141X_UART_MODE_RS485	0x3
+#define XR21V141X_UART_MODE_RS485_ADDR	0x4
+
+#define XR21V141X_REG_ENABLE		0x03
+#define XR21V141X_REG_FORMAT		0x0b
+#define XR21V141X_REG_FLOW_CTRL		0x0c
+#define XR21V141X_REG_XON_CHAR		0x10
+#define XR21V141X_REG_XOFF_CHAR		0x11
+#define XR21V141X_REG_LOOPBACK		0x12
+#define XR21V141X_REG_TX_BREAK		0x14
+#define XR21V141X_REG_RS845_DELAY	0x15
+#define XR21V141X_REG_GPIO_MODE		0x1a
+#define XR21V141X_REG_GPIO_DIR		0x1b
+#define XR21V141X_REG_GPIO_INT_MASK	0x1c
+#define XR21V141X_REG_GPIO_SET		0x1d
+#define XR21V141X_REG_GPIO_CLR		0x1e
+#define XR21V141X_REG_GPIO_STATUS	0x1f
+
+static int xr_set_reg(struct usb_serial_port *port, u8 block, u8 reg, u8 val)
+{
+	struct usb_serial *serial = port->serial;
+	int ret;
+
+	ret = usb_control_msg(serial->dev,
+			      usb_sndctrlpipe(serial->dev, 0),
+			      XR21V141X_SET_REQ,
+			      USB_DIR_OUT | USB_TYPE_VENDOR, val,
+			      reg | (block << 8), NULL, 0,
+			      USB_CTRL_SET_TIMEOUT);
+	if (ret < 0) {
+		dev_err(&port->dev, "Failed to set reg 0x%02x: %d\n", reg, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int xr_get_reg(struct usb_serial_port *port, u8 block, u8 reg, u8 *val)
+{
+	struct usb_serial *serial = port->serial;
+	u8 *dmabuf;
+	int ret;
+
+	dmabuf = kmalloc(1, GFP_KERNEL);
+	if (!dmabuf)
+		return -ENOMEM;
+
+	ret = usb_control_msg(serial->dev,
+			      usb_rcvctrlpipe(serial->dev, 0),
+			      XR21V141X_GET_REQ,
+			      USB_DIR_IN | USB_TYPE_VENDOR, 0,
+			      reg | (block << 8), dmabuf, 1,
+			      USB_CTRL_GET_TIMEOUT);
+	if (ret == 1) {
+		*val = *dmabuf;
+		ret = 0;
+	} else {
+		dev_err(&port->dev, "Failed to get reg 0x%02x: %d\n", reg, ret);
+		if (ret >= 0)
+			ret = -EIO;
+	}
+
+	kfree(dmabuf);
+
+	return ret;
+}
+
+static int xr_set_reg_uart(struct usb_serial_port *port, u8 reg, u8 val)
+{
+	return xr_set_reg(port, XR21V141X_UART_REG_BLOCK, reg, val);
+}
+
+static int xr_get_reg_uart(struct usb_serial_port *port, u8 reg, u8 *val)
+{
+	return xr_get_reg(port, XR21V141X_UART_REG_BLOCK, reg, val);
+}
+
+static int xr_set_reg_um(struct usb_serial_port *port, u8 reg, u8 val)
+{
+	return xr_set_reg(port, XR21V141X_UM_REG_BLOCK, reg, val);
+}
+
+/*
+ * According to datasheet, below is the recommended sequence for enabling UART
+ * module in XR21V141X:
+ *
+ * Enable Tx FIFO
+ * Enable Tx and Rx
+ * Enable Rx FIFO
+ */
+static int xr_uart_enable(struct usb_serial_port *port)
+{
+	int ret;
+
+	ret = xr_set_reg_um(port, XR21V141X_UM_FIFO_ENABLE_REG,
+			    XR21V141X_UM_ENABLE_TX_FIFO);
+	if (ret)
+		return ret;
+
+	ret = xr_set_reg_uart(port, XR21V141X_REG_ENABLE,
+			      XR21V141X_UART_ENABLE_TX | XR21V141X_UART_ENABLE_RX);
+	if (ret)
+		return ret;
+
+	ret = xr_set_reg_um(port, XR21V141X_UM_FIFO_ENABLE_REG,
+			    XR21V141X_UM_ENABLE_TX_FIFO | XR21V141X_UM_ENABLE_RX_FIFO);
+
+	if (ret)
+		xr_set_reg_uart(port, XR21V141X_REG_ENABLE, 0);
+
+	return ret;
+}
+
+static int xr_uart_disable(struct usb_serial_port *port)
+{
+	int ret;
+
+	ret = xr_set_reg_uart(port, XR21V141X_REG_ENABLE, 0);
+	if (ret)
+		return ret;
+
+	ret = xr_set_reg_um(port, XR21V141X_UM_FIFO_ENABLE_REG, 0);
+
+	return ret;
+}
+
+static int xr_tiocmget(struct tty_struct *tty)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	u8 status;
+	int ret;
+
+	ret = xr_get_reg_uart(port, XR21V141X_REG_GPIO_STATUS, &status);
+	if (ret)
+		return ret;
+
+	/*
+	 * Modem control pins are active low, so reading '0' means it is active
+	 * and '1' means not active.
+	 */
+	ret = ((status & XR21V141X_UART_MODE_DTR) ? 0 : TIOCM_DTR) |
+	      ((status & XR21V141X_UART_MODE_RTS) ? 0 : TIOCM_RTS) |
+	      ((status & XR21V141X_UART_MODE_CTS) ? 0 : TIOCM_CTS) |
+	      ((status & XR21V141X_UART_MODE_DSR) ? 0 : TIOCM_DSR) |
+	      ((status & XR21V141X_UART_MODE_RI) ? 0 : TIOCM_RI) |
+	      ((status & XR21V141X_UART_MODE_CD) ? 0 : TIOCM_CD);
+
+	return ret;
+}
+
+static int xr_tiocmset_port(struct usb_serial_port *port,
+			    unsigned int set, unsigned int clear)
+{
+	u8 gpio_set = 0;
+	u8 gpio_clr = 0;
+	int ret = 0;
+
+	/* Modem control pins are active low, so set & clr are swapped */
+	if (set & TIOCM_RTS)
+		gpio_clr |= XR21V141X_UART_MODE_RTS;
+	if (set & TIOCM_DTR)
+		gpio_clr |= XR21V141X_UART_MODE_DTR;
+	if (clear & TIOCM_RTS)
+		gpio_set |= XR21V141X_UART_MODE_RTS;
+	if (clear & TIOCM_DTR)
+		gpio_set |= XR21V141X_UART_MODE_DTR;
+
+	/* Writing '0' to gpio_{set/clr} bits has no effect, so no need to do */
+	if (gpio_clr)
+		ret = xr_set_reg_uart(port, XR21V141X_REG_GPIO_CLR, gpio_clr);
+
+	if (gpio_set)
+		ret = xr_set_reg_uart(port, XR21V141X_REG_GPIO_SET, gpio_set);
+
+	return ret;
+}
+
+static int xr_tiocmset(struct tty_struct *tty,
+		       unsigned int set, unsigned int clear)
+{
+	struct usb_serial_port *port = tty->driver_data;
+
+	return xr_tiocmset_port(port, set, clear);
+}
+
+static void xr_dtr_rts(struct usb_serial_port *port, int on)
+{
+	if (on)
+		xr_tiocmset_port(port, TIOCM_DTR | TIOCM_RTS, 0);
+	else
+		xr_tiocmset_port(port, 0, TIOCM_DTR | TIOCM_RTS);
+}
+
+static void xr_break_ctl(struct tty_struct *tty, int break_state)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	u8 state;
+
+	if (break_state == 0)
+		state = XR21V141X_UART_BREAK_OFF;
+	else
+		state = XR21V141X_UART_BREAK_ON;
+
+	dev_dbg(&port->dev, "Turning break %s\n",
+		state == XR21V141X_UART_BREAK_OFF ? "off" : "on");
+	xr_set_reg_uart(port, XR21V141X_REG_TX_BREAK, state);
+}
+
+/* Tx and Rx clock mask values obtained from section 3.3.4 of datasheet */
+static const struct xr_txrx_clk_mask xr21v141x_txrx_clk_masks[] = {
+	{ 0x000, 0x000, 0x000 },
+	{ 0x000, 0x000, 0x000 },
+	{ 0x100, 0x000, 0x100 },
+	{ 0x020, 0x400, 0x020 },
+	{ 0x010, 0x100, 0x010 },
+	{ 0x208, 0x040, 0x208 },
+	{ 0x104, 0x820, 0x108 },
+	{ 0x844, 0x210, 0x884 },
+	{ 0x444, 0x110, 0x444 },
+	{ 0x122, 0x888, 0x224 },
+	{ 0x912, 0x448, 0x924 },
+	{ 0x492, 0x248, 0x492 },
+	{ 0x252, 0x928, 0x292 },
+	{ 0x94a, 0x4a4, 0xa52 },
+	{ 0x52a, 0xaa4, 0x54a },
+	{ 0xaaa, 0x954, 0x4aa },
+	{ 0xaaa, 0x554, 0xaaa },
+	{ 0x555, 0xad4, 0x5aa },
+	{ 0xb55, 0xab4, 0x55a },
+	{ 0x6b5, 0x5ac, 0xb56 },
+	{ 0x5b5, 0xd6c, 0x6d6 },
+	{ 0xb6d, 0xb6a, 0xdb6 },
+	{ 0x76d, 0x6da, 0xbb6 },
+	{ 0xedd, 0xdda, 0x76e },
+	{ 0xddd, 0xbba, 0xeee },
+	{ 0x7bb, 0xf7a, 0xdde },
+	{ 0xf7b, 0xef6, 0x7de },
+	{ 0xdf7, 0xbf6, 0xf7e },
+	{ 0x7f7, 0xfee, 0xefe },
+	{ 0xfdf, 0xfbe, 0x7fe },
+	{ 0xf7f, 0xefe, 0xffe },
+	{ 0xfff, 0xffe, 0xffd },
+};
+
+static int xr_set_baudrate(struct tty_struct *tty,
+			   struct usb_serial_port *port)
+{
+	u32 divisor, baud, idx;
+	u16 tx_mask, rx_mask;
+	int ret;
+
+	baud = clamp(tty->termios.c_ospeed, XR21V141X_MIN_SPEED,
+		     XR21V141X_MAX_SPEED);
+	divisor = XR_INT_OSC_HZ / baud;
+	idx = ((32 * XR_INT_OSC_HZ) / baud) & 0x1f;
+	tx_mask = xr21v141x_txrx_clk_masks[idx].tx;
+
+	if (divisor & 0x01)
+		rx_mask = xr21v141x_txrx_clk_masks[idx].rx1;
+	else
+		rx_mask = xr21v141x_txrx_clk_masks[idx].rx0;
+
+	dev_dbg(&port->dev, "Setting baud rate: %u\n", baud);
+	/*
+	 * XR21V141X uses fractional baud rate generator with 48MHz internal
+	 * oscillator and 19-bit programmable divisor. So theoretically it can
+	 * generate most commonly used baud rates with high accuracy.
+	 */
+	ret = xr_set_reg_uart(port, XR21V141X_CLOCK_DIVISOR_0,
+			      divisor & 0xff);
+	if (ret)
+		return ret;
+
+	ret = xr_set_reg_uart(port, XR21V141X_CLOCK_DIVISOR_1,
+			      (divisor >>  8) & 0xff);
+	if (ret)
+		return ret;
+
+	ret = xr_set_reg_uart(port, XR21V141X_CLOCK_DIVISOR_2,
+			      (divisor >> 16) & 0xff);
+	if (ret)
+		return ret;
+
+	ret = xr_set_reg_uart(port, XR21V141X_TX_CLOCK_MASK_0,
+			      tx_mask & 0xff);
+	if (ret)
+		return ret;
+
+	ret = xr_set_reg_uart(port, XR21V141X_TX_CLOCK_MASK_1,
+			      (tx_mask >>  8) & 0xff);
+	if (ret)
+		return ret;
+
+	ret = xr_set_reg_uart(port, XR21V141X_RX_CLOCK_MASK_0,
+			      rx_mask & 0xff);
+	if (ret)
+		return ret;
+
+	ret = xr_set_reg_uart(port, XR21V141X_RX_CLOCK_MASK_1,
+			      (rx_mask >>  8) & 0xff);
+	if (ret)
+		return ret;
+
+	tty_encode_baud_rate(tty, baud, baud);
+
+	return 0;
+}
+
+static void xr_set_flow_mode(struct tty_struct *tty,
+			     struct usb_serial_port *port)
+{
+	unsigned int cflag = tty->termios.c_cflag;
+	u8 flow, gpio_mode;
+	int ret;
+
+	ret = xr_get_reg_uart(port, XR21V141X_REG_GPIO_MODE, &gpio_mode);
+	if (ret)
+		return;
+
+	if (cflag & CRTSCTS) {
+		dev_dbg(&port->dev, "Enabling hardware flow ctrl\n");
+
+		/*
+		 * RTS/CTS is the default flow control mode, so set GPIO mode
+		 * for controlling the pins manually by default.
+		 */
+		gpio_mode &= ~XR21V141X_UART_MODE_GPIO_MASK;
+		gpio_mode |= XR21V141X_UART_MODE_RTS_CTS;
+		flow = XR21V141X_UART_FLOW_MODE_HW;
+	} else if (I_IXON(tty)) {
+		u8 start_char = START_CHAR(tty);
+		u8 stop_char = STOP_CHAR(tty);
+
+		dev_dbg(&port->dev, "Enabling sw flow ctrl\n");
+		flow = XR21V141X_UART_FLOW_MODE_SW;
+
+		xr_set_reg_uart(port, XR21V141X_REG_XON_CHAR, start_char);
+		xr_set_reg_uart(port, XR21V141X_REG_XOFF_CHAR, stop_char);
+	} else {
+		dev_dbg(&port->dev, "Disabling flow ctrl\n");
+		flow = XR21V141X_UART_FLOW_MODE_NONE;
+	}
+
+	/*
+	 * As per the datasheet, UART needs to be disabled while writing to
+	 * FLOW_CONTROL register.
+	 */
+	xr_uart_disable(port);
+	xr_set_reg_uart(port, XR21V141X_REG_FLOW_CTRL, flow);
+	xr_uart_enable(port);
+
+	xr_set_reg_uart(port, XR21V141X_REG_GPIO_MODE, gpio_mode);
+}
+
+static void xr_set_termios(struct tty_struct *tty,
+			   struct usb_serial_port *port,
+			   struct ktermios *old_termios)
+{
+	struct ktermios *termios = &tty->termios;
+	u8 bits = 0;
+	int ret;
+
+	if ((old_termios && tty->termios.c_ospeed != old_termios->c_ospeed) ||
+	    !old_termios)
+		xr_set_baudrate(tty, port);
+
+	switch (C_CSIZE(tty)) {
+	case CS5:
+	case CS6:
+		/* CS5 and CS6 are not supported, so just restore old setting */
+		termios->c_cflag &= ~CSIZE;
+		if (old_termios)
+			termios->c_cflag |= old_termios->c_cflag & CSIZE;
+		else
+			bits |= XR21V141X_UART_DATA_8;
+		break;
+	case CS7:
+		bits |= XR21V141X_UART_DATA_7;
+		break;
+	case CS8:
+	default:
+		bits |= XR21V141X_UART_DATA_8;
+		break;
+	}
+
+	if (C_PARENB(tty)) {
+		if (C_CMSPAR(tty)) {
+			if (C_PARODD(tty))
+				bits |= XR21V141X_UART_PARITY_MARK <<
+					XR21V141X_UART_PARITY_SHIFT;
+			else
+				bits |= XR21V141X_UART_PARITY_SPACE <<
+					XR21V141X_UART_PARITY_SHIFT;
+		} else {
+			if (C_PARODD(tty))
+				bits |= XR21V141X_UART_PARITY_ODD <<
+					XR21V141X_UART_PARITY_SHIFT;
+			else
+				bits |= XR21V141X_UART_PARITY_EVEN <<
+					XR21V141X_UART_PARITY_SHIFT;
+		}
+	}
+
+	if (C_CSTOPB(tty))
+		bits |= XR21V141X_UART_STOP_2 << XR21V141X_UART_STOP_SHIFT;
+	else
+		bits |= XR21V141X_UART_STOP_1 << XR21V141X_UART_STOP_SHIFT;
+
+	ret = xr_set_reg_uart(port, XR21V141X_REG_FORMAT, bits);
+	if (ret)
+		return;
+
+	/* If baud rate is B0, clear DTR and RTS */
+	if (C_BAUD(tty) == B0)
+		xr_dtr_rts(port, 0);
+
+	xr_set_flow_mode(tty, port);
+}
+
+static int xr_open(struct tty_struct *tty, struct usb_serial_port *port)
+{
+	int ret;
+
+	ret = xr_uart_enable(port);
+	if (ret) {
+		dev_err(&port->dev, "Failed to enable UART\n");
+		return ret;
+	}
+
+	/* Setup termios */
+	if (tty)
+		xr_set_termios(tty, port, NULL);
+
+	ret = usb_serial_generic_open(tty, port);
+	if (ret) {
+		xr_uart_disable(port);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void xr_close(struct usb_serial_port *port)
+{
+	usb_serial_generic_close(port);
+
+	xr_uart_disable(port);
+}
+
+static int xr_probe(struct usb_serial *serial, const struct usb_device_id *id)
+{
+	struct usb_device *usb_dev = interface_to_usbdev(serial->interface);
+	struct usb_driver *driver = serial->type->usb_driver;
+	struct usb_interface *control_interface;
+	int ret;
+
+	/* Don't bind to control interface */
+	if (serial->interface->cur_altsetting->desc.bInterfaceNumber == 0)
+		return -ENODEV;
+
+	/* But claim the control interface during data interface probe */
+	control_interface = usb_ifnum_to_if(usb_dev, 0);
+	ret = usb_driver_claim_interface(driver, control_interface, NULL);
+	if (ret) {
+		dev_err(&serial->interface->dev, "Failed to claim control interface\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct usb_device_id id_table[] = {
+	{ USB_DEVICE(0x04e2, 0x1410) }, /* XR21V141X */
+	{ }
+};
+MODULE_DEVICE_TABLE(usb, id_table);
+
+static struct usb_serial_driver xr_device = {
+	.driver = {
+		.owner = THIS_MODULE,
+		.name =	"xr_serial",
+	},
+	.id_table		= id_table,
+	.num_ports		= 1,
+	.probe			= xr_probe,
+	.open			= xr_open,
+	.close			= xr_close,
+	.break_ctl		= xr_break_ctl,
+	.set_termios		= xr_set_termios,
+	.tiocmget		= xr_tiocmget,
+	.tiocmset		= xr_tiocmset,
+	.dtr_rts		= xr_dtr_rts
+};
+
+static struct usb_serial_driver * const serial_drivers[] = {
+	&xr_device, NULL
+};
+
+module_usb_serial_driver(serial_drivers, id_table);
+
+MODULE_AUTHOR("Manivannan Sadhasivam <mani@kernel.org>");
+MODULE_DESCRIPTION("MaxLinear/Exar USB to Serial driver");
+MODULE_LICENSE("GPL");

From 5f6225a7fb2c863ca40ca282478933c0afdb3512 Mon Sep 17 00:00:00 2001
From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Date: Sun, 22 Nov 2020 22:38:22 +0530
Subject: [PATCH 16/41] USB: cdc-acm: ignore Exar XR21V141X when serial driver
 is built

The Exar XR21V141X can be used in either ACM mode using the cdc-acm
driver or in "custom driver" mode in which further features such as
hardware and software flow control, GPIO control and in-band line-status
reporting are available.

In ACM mode the device always enables RTS/CTS flow control, something
which could prevent transmission in case the CTS input isn't wired up
correctly.

Ensure that cdc_acm will not bind to the device if the custom USB-serial
driver is enabled.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://lore.kernel.org/r/20201122170822.21715-4-mani@kernel.org
[ johan: rewrite commit message ]
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/class/cdc-acm.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 781905745812..37f824b59daa 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1901,6 +1901,12 @@ static const struct usb_device_id acm_ids[] = {
 	},
 #endif
 
+#if IS_ENABLED(CONFIG_USB_SERIAL_XR)
+	{ USB_DEVICE(0x04e2, 0x1410),   /* Ignore XR21V141X USB to Serial converter */
+	.driver_info = IGNORE_DEVICE,
+	},
+#endif
+
 	/*Samsung phone in firmware update mode */
 	{ USB_DEVICE(0x04e8, 0x685d),
 	.driver_info = IGNORE_DEVICE,

From a70aa7dc60099bbdcbd6faca42a915d80f31161e Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Tue, 26 Jan 2021 13:26:54 +0300
Subject: [PATCH 17/41] USB: serial: mos7840: fix error code in mos7840_write()

This should return -ENOMEM instead of 0 if the kmalloc() fails.

Fixes: 3f5429746d91 ("USB: Moschip 7840 USB-Serial Driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/mos7840.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 23f91d658cb4..30c25ef0dacd 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -883,8 +883,10 @@ static int mos7840_write(struct tty_struct *tty, struct usb_serial_port *port,
 	if (urb->transfer_buffer == NULL) {
 		urb->transfer_buffer = kmalloc(URB_TRANSFER_BUFFER_SIZE,
 					       GFP_ATOMIC);
-		if (!urb->transfer_buffer)
+		if (!urb->transfer_buffer) {
+			bytes_sent = -ENOMEM;
 			goto exit;
+		}
 	}
 	transfer_size = min(count, URB_TRANSFER_BUFFER_SIZE);
 

From a38d21488097f9823ebd297d56b24f431ee7acaa Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Thu, 21 Jan 2021 11:29:13 +0100
Subject: [PATCH 18/41] USB: serial: xr: fix NULL-deref at probe

Make sure that the probed device has an interface 0 to avoid
dereferencing a NULL pointer in case of a malicious device or during
USB-descriptor fuzzing.

Fixes: c2d405aa86b4 ("USB: serial: add MaxLinear/Exar USB to Serial driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/xr_serial.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c
index bdb2df27b50b..7be6da6a5cf3 100644
--- a/drivers/usb/serial/xr_serial.c
+++ b/drivers/usb/serial/xr_serial.c
@@ -552,6 +552,9 @@ static int xr_probe(struct usb_serial *serial, const struct usb_device_id *id)
 
 	/* But claim the control interface during data interface probe */
 	control_interface = usb_ifnum_to_if(usb_dev, 0);
+	if (!control_interface)
+		return -ENODEV;
+
 	ret = usb_driver_claim_interface(driver, control_interface, NULL);
 	if (ret) {
 		dev_err(&serial->interface->dev, "Failed to claim control interface\n");

From 54c98d9d7ba48c66d64f72e3d5a7586601705611 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Thu, 21 Jan 2021 11:29:14 +0100
Subject: [PATCH 19/41] USB: serial: xr: fix interface leak at disconnect

Make sure to release the control interface at disconnect so that the
driver can be unbound without leaking resources (and later rebound).

Fixes: c2d405aa86b4 ("USB: serial: add MaxLinear/Exar USB to Serial driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/xr_serial.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c
index 7be6da6a5cf3..5e110b0c8e71 100644
--- a/drivers/usb/serial/xr_serial.c
+++ b/drivers/usb/serial/xr_serial.c
@@ -564,6 +564,15 @@ static int xr_probe(struct usb_serial *serial, const struct usb_device_id *id)
 	return 0;
 }
 
+static void xr_disconnect(struct usb_serial *serial)
+{
+	struct usb_driver *driver = serial->type->usb_driver;
+	struct usb_interface *control_interface;
+
+	control_interface = usb_ifnum_to_if(serial->dev, 0);
+	usb_driver_release_interface(driver, control_interface);
+}
+
 static const struct usb_device_id id_table[] = {
 	{ USB_DEVICE(0x04e2, 0x1410) }, /* XR21V141X */
 	{ }
@@ -578,6 +587,7 @@ static struct usb_serial_driver xr_device = {
 	.id_table		= id_table,
 	.num_ports		= 1,
 	.probe			= xr_probe,
+	.disconnect		= xr_disconnect,
 	.open			= xr_open,
 	.close			= xr_close,
 	.break_ctl		= xr_break_ctl,

From 9ffa6ec51ce8595ffaa5a634bd5618e129d038c0 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Thu, 21 Jan 2021 11:29:15 +0100
Subject: [PATCH 20/41] USB: serial: xr: use subsystem usb_device at probe

Use the subsystem struct usb_device pointer at probe instead of
deriving it from the interface pointer.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/xr_serial.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c
index 5e110b0c8e71..8f81f866d681 100644
--- a/drivers/usb/serial/xr_serial.c
+++ b/drivers/usb/serial/xr_serial.c
@@ -541,7 +541,6 @@ static void xr_close(struct usb_serial_port *port)
 
 static int xr_probe(struct usb_serial *serial, const struct usb_device_id *id)
 {
-	struct usb_device *usb_dev = interface_to_usbdev(serial->interface);
 	struct usb_driver *driver = serial->type->usb_driver;
 	struct usb_interface *control_interface;
 	int ret;
@@ -551,7 +550,7 @@ static int xr_probe(struct usb_serial *serial, const struct usb_device_id *id)
 		return -ENODEV;
 
 	/* But claim the control interface during data interface probe */
-	control_interface = usb_ifnum_to_if(usb_dev, 0);
+	control_interface = usb_ifnum_to_if(serial->dev, 0);
 	if (!control_interface)
 		return -ENODEV;
 

From 5c5d9af683f61bf0984f06db0d1357e94b5e2655 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Thu, 21 Jan 2021 11:29:16 +0100
Subject: [PATCH 21/41] USB: serial: xr: use termios flag helpers

Use the termios flag helpers consistently, including for CRTSCTS.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/xr_serial.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c
index 8f81f866d681..52909dccb4dc 100644
--- a/drivers/usb/serial/xr_serial.c
+++ b/drivers/usb/serial/xr_serial.c
@@ -401,7 +401,6 @@ static int xr_set_baudrate(struct tty_struct *tty,
 static void xr_set_flow_mode(struct tty_struct *tty,
 			     struct usb_serial_port *port)
 {
-	unsigned int cflag = tty->termios.c_cflag;
 	u8 flow, gpio_mode;
 	int ret;
 
@@ -409,7 +408,7 @@ static void xr_set_flow_mode(struct tty_struct *tty,
 	if (ret)
 		return;
 
-	if (cflag & CRTSCTS) {
+	if (C_CRTSCTS(tty)) {
 		dev_dbg(&port->dev, "Enabling hardware flow ctrl\n");
 
 		/*

From 72fc7fc7f36501103a5ffa0d29c9672b2314ce29 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Thu, 21 Jan 2021 11:29:17 +0100
Subject: [PATCH 22/41] USB: serial: xr: document vendor-request recipient

Add the missing device-recipient define to the vendor control requests
for completeness.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/xr_serial.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c
index 52909dccb4dc..202263211ba9 100644
--- a/drivers/usb/serial/xr_serial.c
+++ b/drivers/usb/serial/xr_serial.c
@@ -116,8 +116,8 @@ static int xr_set_reg(struct usb_serial_port *port, u8 block, u8 reg, u8 val)
 	ret = usb_control_msg(serial->dev,
 			      usb_sndctrlpipe(serial->dev, 0),
 			      XR21V141X_SET_REQ,
-			      USB_DIR_OUT | USB_TYPE_VENDOR, val,
-			      reg | (block << 8), NULL, 0,
+			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			      val, reg | (block << 8), NULL, 0,
 			      USB_CTRL_SET_TIMEOUT);
 	if (ret < 0) {
 		dev_err(&port->dev, "Failed to set reg 0x%02x: %d\n", reg, ret);
@@ -140,8 +140,8 @@ static int xr_get_reg(struct usb_serial_port *port, u8 block, u8 reg, u8 *val)
 	ret = usb_control_msg(serial->dev,
 			      usb_rcvctrlpipe(serial->dev, 0),
 			      XR21V141X_GET_REQ,
-			      USB_DIR_IN | USB_TYPE_VENDOR, 0,
-			      reg | (block << 8), dmabuf, 1,
+			      USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			      0, reg | (block << 8), dmabuf, 1,
 			      USB_CTRL_GET_TIMEOUT);
 	if (ret == 1) {
 		*val = *dmabuf;

From 35567511595052a2c6fc020d4abab944fb4204b0 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Thu, 21 Jan 2021 11:29:18 +0100
Subject: [PATCH 23/41] USB: serial: xr: clean up line-settings handling

Shift the line-setting values when defining them rather than in
set_termios() for consistency and improved readability.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/xr_serial.c | 34 +++++++++++++++-------------------
 1 file changed, 15 insertions(+), 19 deletions(-)

diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c
index 202263211ba9..2000277bacc1 100644
--- a/drivers/usb/serial/xr_serial.c
+++ b/drivers/usb/serial/xr_serial.c
@@ -71,17 +71,17 @@ struct xr_txrx_clk_mask {
 #define XR21V141X_UART_DATA_8		0x8
 
 #define XR21V141X_UART_PARITY_MASK	GENMASK(6, 4)
-#define XR21V141X_UART_PARITY_SHIFT	0x4
-#define XR21V141X_UART_PARITY_NONE	0x0
-#define XR21V141X_UART_PARITY_ODD	0x1
-#define XR21V141X_UART_PARITY_EVEN	0x2
-#define XR21V141X_UART_PARITY_MARK	0x3
-#define XR21V141X_UART_PARITY_SPACE	0x4
+#define XR21V141X_UART_PARITY_SHIFT	4
+#define XR21V141X_UART_PARITY_NONE	(0x0 << XR21V141X_UART_PARITY_SHIFT)
+#define XR21V141X_UART_PARITY_ODD	(0x1 << XR21V141X_UART_PARITY_SHIFT)
+#define XR21V141X_UART_PARITY_EVEN	(0x2 << XR21V141X_UART_PARITY_SHIFT)
+#define XR21V141X_UART_PARITY_MARK	(0x3 << XR21V141X_UART_PARITY_SHIFT)
+#define XR21V141X_UART_PARITY_SPACE	(0x4 << XR21V141X_UART_PARITY_SHIFT)
 
 #define XR21V141X_UART_STOP_MASK	BIT(7)
-#define XR21V141X_UART_STOP_SHIFT	0x7
-#define XR21V141X_UART_STOP_1		0x0
-#define XR21V141X_UART_STOP_2		0x1
+#define XR21V141X_UART_STOP_SHIFT	7
+#define XR21V141X_UART_STOP_1		(0x0 << XR21V141X_UART_STOP_SHIFT)
+#define XR21V141X_UART_STOP_2		(0x1 << XR21V141X_UART_STOP_SHIFT)
 
 #define XR21V141X_UART_FLOW_MODE_NONE	0x0
 #define XR21V141X_UART_FLOW_MODE_HW	0x1
@@ -477,25 +477,21 @@ static void xr_set_termios(struct tty_struct *tty,
 	if (C_PARENB(tty)) {
 		if (C_CMSPAR(tty)) {
 			if (C_PARODD(tty))
-				bits |= XR21V141X_UART_PARITY_MARK <<
-					XR21V141X_UART_PARITY_SHIFT;
+				bits |= XR21V141X_UART_PARITY_MARK;
 			else
-				bits |= XR21V141X_UART_PARITY_SPACE <<
-					XR21V141X_UART_PARITY_SHIFT;
+				bits |= XR21V141X_UART_PARITY_SPACE;
 		} else {
 			if (C_PARODD(tty))
-				bits |= XR21V141X_UART_PARITY_ODD <<
-					XR21V141X_UART_PARITY_SHIFT;
+				bits |= XR21V141X_UART_PARITY_ODD;
 			else
-				bits |= XR21V141X_UART_PARITY_EVEN <<
-					XR21V141X_UART_PARITY_SHIFT;
+				bits |= XR21V141X_UART_PARITY_EVEN;
 		}
 	}
 
 	if (C_CSTOPB(tty))
-		bits |= XR21V141X_UART_STOP_2 << XR21V141X_UART_STOP_SHIFT;
+		bits |= XR21V141X_UART_STOP_2;
 	else
-		bits |= XR21V141X_UART_STOP_1 << XR21V141X_UART_STOP_SHIFT;
+		bits |= XR21V141X_UART_STOP_1;
 
 	ret = xr_set_reg_uart(port, XR21V141X_REG_FORMAT, bits);
 	if (ret)

From 736c09316c905622c548582a47eaa2c8c542b520 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Thu, 21 Jan 2021 11:29:19 +0100
Subject: [PATCH 24/41] USB: serial: xr: simplify line-speed logic

Simplify the changed-line-speed conditional expression.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/xr_serial.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c
index 2000277bacc1..fc727f4283f2 100644
--- a/drivers/usb/serial/xr_serial.c
+++ b/drivers/usb/serial/xr_serial.c
@@ -451,8 +451,7 @@ static void xr_set_termios(struct tty_struct *tty,
 	u8 bits = 0;
 	int ret;
 
-	if ((old_termios && tty->termios.c_ospeed != old_termios->c_ospeed) ||
-	    !old_termios)
+	if (!old_termios || (tty->termios.c_ospeed != old_termios->c_ospeed))
 		xr_set_baudrate(tty, port);
 
 	switch (C_CSIZE(tty)) {

From 465d3b3a0d311680d0e42258fd25454433667e9d Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Thu, 21 Jan 2021 11:29:20 +0100
Subject: [PATCH 25/41] USB: serial: xr: fix gpio-mode handling

Fix the gpio-mode handling so that all the pins are under driver control
(i.e. in gpio mode) when hardware flow control is disabled.

This is specifically needed to be able to control RTS.

Fixes: c2d405aa86b4 ("USB: serial: add MaxLinear/Exar USB to Serial driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/xr_serial.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c
index fc727f4283f2..183731cd2ef7 100644
--- a/drivers/usb/serial/xr_serial.c
+++ b/drivers/usb/serial/xr_serial.c
@@ -408,14 +408,11 @@ static void xr_set_flow_mode(struct tty_struct *tty,
 	if (ret)
 		return;
 
+	/* Set GPIO mode for controlling the pins manually by default. */
+	gpio_mode &= ~XR21V141X_UART_MODE_GPIO_MASK;
+
 	if (C_CRTSCTS(tty)) {
 		dev_dbg(&port->dev, "Enabling hardware flow ctrl\n");
-
-		/*
-		 * RTS/CTS is the default flow control mode, so set GPIO mode
-		 * for controlling the pins manually by default.
-		 */
-		gpio_mode &= ~XR21V141X_UART_MODE_GPIO_MASK;
 		gpio_mode |= XR21V141X_UART_MODE_RTS_CTS;
 		flow = XR21V141X_UART_FLOW_MODE_HW;
 	} else if (I_IXON(tty)) {

From 0d05d7d913892cd093acc5a0ac884ebab9fda67c Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Thu, 21 Jan 2021 11:29:21 +0100
Subject: [PATCH 26/41] USB: serial: xr: fix pin configuration

Make sure that the modem pins are set up correctly when opening the
port to avoid leaving, for example, DTR and RTS configured as inputs,
which is the device default.

This is specifically needed to be able to control DTR and RTS when
hardware flow control is disabled.

Fixes: c2d405aa86b4 ("USB: serial: add MaxLinear/Exar USB to Serial driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/xr_serial.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c
index 183731cd2ef7..f67e7dba9509 100644
--- a/drivers/usb/serial/xr_serial.c
+++ b/drivers/usb/serial/xr_serial.c
@@ -502,6 +502,7 @@ static void xr_set_termios(struct tty_struct *tty,
 
 static int xr_open(struct tty_struct *tty, struct usb_serial_port *port)
 {
+	u8 gpio_dir;
 	int ret;
 
 	ret = xr_uart_enable(port);
@@ -510,6 +511,13 @@ static int xr_open(struct tty_struct *tty, struct usb_serial_port *port)
 		return ret;
 	}
 
+	/*
+	 * Configure DTR and RTS as outputs and RI, CD, DSR and CTS as
+	 * inputs.
+	 */
+	gpio_dir = XR21V141X_UART_MODE_DTR | XR21V141X_UART_MODE_RTS;
+	xr_set_reg_uart(port, XR21V141X_REG_GPIO_DIR, gpio_dir);
+
 	/* Setup termios */
 	if (tty)
 		xr_set_termios(tty, port, NULL);

From 55317e22391ffc5aa297c3a617c8c3302fb184b6 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Thu, 21 Jan 2021 11:29:22 +0100
Subject: [PATCH 27/41] USB: serial: xr: fix B0 handling

Fix up B0 handling which should leave the baud rate unchanged and
specifically not report back a non-B0 rate when B0 is requested; must
temporarily disable hardware flow control so that RTS can be deasserted;
and should reassert DTR/RTS when moving from B0.

Fixes: c2d405aa86b4 ("USB: serial: add MaxLinear/Exar USB to Serial driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/xr_serial.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c
index f67e7dba9509..483d07dee19d 100644
--- a/drivers/usb/serial/xr_serial.c
+++ b/drivers/usb/serial/xr_serial.c
@@ -341,8 +341,11 @@ static int xr_set_baudrate(struct tty_struct *tty,
 	u16 tx_mask, rx_mask;
 	int ret;
 
-	baud = clamp(tty->termios.c_ospeed, XR21V141X_MIN_SPEED,
-		     XR21V141X_MAX_SPEED);
+	baud = tty->termios.c_ospeed;
+	if (!baud)
+		return 0;
+
+	baud = clamp(baud, XR21V141X_MIN_SPEED, XR21V141X_MAX_SPEED);
 	divisor = XR_INT_OSC_HZ / baud;
 	idx = ((32 * XR_INT_OSC_HZ) / baud) & 0x1f;
 	tx_mask = xr21v141x_txrx_clk_masks[idx].tx;
@@ -399,7 +402,8 @@ static int xr_set_baudrate(struct tty_struct *tty,
 }
 
 static void xr_set_flow_mode(struct tty_struct *tty,
-			     struct usb_serial_port *port)
+			     struct usb_serial_port *port,
+			     struct ktermios *old_termios)
 {
 	u8 flow, gpio_mode;
 	int ret;
@@ -411,7 +415,7 @@ static void xr_set_flow_mode(struct tty_struct *tty,
 	/* Set GPIO mode for controlling the pins manually by default. */
 	gpio_mode &= ~XR21V141X_UART_MODE_GPIO_MASK;
 
-	if (C_CRTSCTS(tty)) {
+	if (C_CRTSCTS(tty) && C_BAUD(tty) != B0) {
 		dev_dbg(&port->dev, "Enabling hardware flow ctrl\n");
 		gpio_mode |= XR21V141X_UART_MODE_RTS_CTS;
 		flow = XR21V141X_UART_FLOW_MODE_HW;
@@ -438,6 +442,11 @@ static void xr_set_flow_mode(struct tty_struct *tty,
 	xr_uart_enable(port);
 
 	xr_set_reg_uart(port, XR21V141X_REG_GPIO_MODE, gpio_mode);
+
+	if (C_BAUD(tty) == B0)
+		xr_dtr_rts(port, 0);
+	else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
+		xr_dtr_rts(port, 1);
 }
 
 static void xr_set_termios(struct tty_struct *tty,
@@ -493,11 +502,7 @@ static void xr_set_termios(struct tty_struct *tty,
 	if (ret)
 		return;
 
-	/* If baud rate is B0, clear DTR and RTS */
-	if (C_BAUD(tty) == B0)
-		xr_dtr_rts(port, 0);
-
-	xr_set_flow_mode(tty, port);
+	xr_set_flow_mode(tty, port, old_termios);
 }
 
 static int xr_open(struct tty_struct *tty, struct usb_serial_port *port)

From fea7372cbc40869876df0f045e367f6f97a1666c Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Thu, 28 Jan 2021 12:35:23 +0300
Subject: [PATCH 28/41] USB: serial: mos7720: fix error code in mos7720_write()

This code should return -ENOMEM if the kmalloc() fails but instead
it returns success.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 0f64478cbc7a ("USB: add USB serial mos7720 driver")
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/mos7720.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index ed347a6d50ba..aa55169796a3 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -1094,8 +1094,10 @@ static int mos7720_write(struct tty_struct *tty, struct usb_serial_port *port,
 	if (urb->transfer_buffer == NULL) {
 		urb->transfer_buffer = kmalloc(URB_TRANSFER_BUFFER_SIZE,
 					       GFP_ATOMIC);
-		if (!urb->transfer_buffer)
+		if (!urb->transfer_buffer) {
+			bytes_sent = -ENOMEM;
 			goto exit;
+		}
 	}
 	transfer_size = min(count, URB_TRANSFER_BUFFER_SIZE);
 

From 5951b8508855799fbb2d6a9553ab3b7af595ea94 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 25 Jan 2021 14:48:11 +0100
Subject: [PATCH 29/41] USB: serial: cp210x: suppress modem-control errors

The CP210X_SET_MHS request cannot be used to control RTS when hardware
flow control (auto-RTS) is enabled and instead returns an error which is
currently logged as:

	cp210x ttyUSB0: failed set request 0x7 status: -32

when opening and closing a port (and on TIOCMSET requests).

Add a crtscts flag to keep track of the hardware flow-control setting
and use it to suppress any request to change RTS when auto-RTS is
enabled.

Note that RTS is still deasserted when disabling the UART as part of
close.

Reported-by: Pho Tran <pho.tran@silabs.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/cp210x.c | 33 ++++++++++++++++++++++++++++++---
 1 file changed, 30 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index d813a052738f..7e4a09b42c99 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -21,6 +21,7 @@
 #include <linux/usb/serial.h>
 #include <linux/gpio/driver.h>
 #include <linux/bitops.h>
+#include <linux/mutex.h>
 
 #define DRIVER_DESC "Silicon Labs CP210x RS232 serial adaptor driver"
 
@@ -264,7 +265,10 @@ struct cp210x_port_private {
 	u8			bInterfaceNumber;
 	bool			event_mode;
 	enum cp210x_event_state event_state;
-	u8 lsr;
+	u8			lsr;
+
+	struct mutex		mutex;
+	bool			crtscts;
 };
 
 static struct usb_serial_driver cp210x_device = {
@@ -1117,6 +1121,7 @@ static bool cp210x_termios_change(const struct ktermios *a, const struct ktermio
 static void cp210x_set_flow_control(struct tty_struct *tty,
 		struct usb_serial_port *port, struct ktermios *old_termios)
 {
+	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
 	struct cp210x_special_chars chars;
 	struct cp210x_flow_ctl flow_ctl;
 	u32 flow_repl;
@@ -1143,10 +1148,12 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
 			return;
 	}
 
+	mutex_lock(&port_priv->mutex);
+
 	ret = cp210x_read_reg_block(port, CP210X_GET_FLOW, &flow_ctl,
 			sizeof(flow_ctl));
 	if (ret)
-		return;
+		goto out_unlock;
 
 	ctl_hs = le32_to_cpu(flow_ctl.ulControlHandshake);
 	flow_repl = le32_to_cpu(flow_ctl.ulFlowReplace);
@@ -1161,10 +1168,12 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
 		ctl_hs |= CP210X_SERIAL_CTS_HANDSHAKE;
 		flow_repl &= ~CP210X_SERIAL_RTS_MASK;
 		flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_FLOW_CTL);
+		port_priv->crtscts = true;
 	} else {
 		ctl_hs &= ~CP210X_SERIAL_CTS_HANDSHAKE;
 		flow_repl &= ~CP210X_SERIAL_RTS_MASK;
 		flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_ACTIVE);
+		port_priv->crtscts = false;
 	}
 
 	if (I_IXOFF(tty))
@@ -1188,6 +1197,8 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
 
 	cp210x_write_reg_block(port, CP210X_SET_FLOW, &flow_ctl,
 			sizeof(flow_ctl));
+out_unlock:
+	mutex_unlock(&port_priv->mutex);
 }
 
 static void cp210x_set_termios(struct tty_struct *tty,
@@ -1272,7 +1283,9 @@ static int cp210x_tiocmset(struct tty_struct *tty,
 static int cp210x_tiocmset_port(struct usb_serial_port *port,
 		unsigned int set, unsigned int clear)
 {
+	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
 	u16 control = 0;
+	int ret;
 
 	if (set & TIOCM_RTS) {
 		control |= CONTROL_RTS;
@@ -1291,9 +1304,22 @@ static int cp210x_tiocmset_port(struct usb_serial_port *port,
 		control |= CONTROL_WRITE_DTR;
 	}
 
+	mutex_lock(&port_priv->mutex);
+
+	/*
+	 * SET_MHS cannot be used to control RTS when auto-RTS is enabled.
+	 * Note that RTS is still deasserted when disabling the UART on close.
+	 */
+	if (port_priv->crtscts)
+		control &= ~CONTROL_WRITE_RTS;
+
 	dev_dbg(&port->dev, "%s - control = 0x%.4x\n", __func__, control);
 
-	return cp210x_write_u16_reg(port, CP210X_SET_MHS, control);
+	ret = cp210x_write_u16_reg(port, CP210X_SET_MHS, control);
+
+	mutex_unlock(&port_priv->mutex);
+
+	return ret;
 }
 
 static void cp210x_dtr_rts(struct usb_serial_port *port, int on)
@@ -1770,6 +1796,7 @@ static int cp210x_port_probe(struct usb_serial_port *port)
 		return -ENOMEM;
 
 	port_priv->bInterfaceNumber = cp210x_interface_num(serial);
+	mutex_init(&port_priv->mutex);
 
 	usb_set_serial_port_data(port, port_priv);
 

From 8cce3bbfb4cffce097c823c29ba487d5a7422d37 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 25 Jan 2021 14:48:12 +0100
Subject: [PATCH 30/41] USB: serial: cp210x: fix modem-control handling

The vendor request used to set the flow-control settings also sets the
state of the modem-control lines.

Add state variables to keep track of the modem-control lines to avoid
always asserting the lines whenever the flow-control settings are
updated.

This specifically also avoids asserting DTR/RTS when opening a port with
the line speed set to B0.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/cp210x.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 7e4a09b42c99..9378b4bba34b 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -269,6 +269,8 @@ struct cp210x_port_private {
 
 	struct mutex		mutex;
 	bool			crtscts;
+	bool			dtr;
+	bool			rts;
 };
 
 static struct usb_serial_driver cp210x_device = {
@@ -1162,7 +1164,10 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
 	ctl_hs &= ~CP210X_SERIAL_DCD_HANDSHAKE;
 	ctl_hs &= ~CP210X_SERIAL_DSR_SENSITIVITY;
 	ctl_hs &= ~CP210X_SERIAL_DTR_MASK;
-	ctl_hs |= CP210X_SERIAL_DTR_SHIFT(CP210X_SERIAL_DTR_ACTIVE);
+	if (port_priv->dtr)
+		ctl_hs |= CP210X_SERIAL_DTR_SHIFT(CP210X_SERIAL_DTR_ACTIVE);
+	else
+		ctl_hs |= CP210X_SERIAL_DTR_SHIFT(CP210X_SERIAL_DTR_INACTIVE);
 
 	if (C_CRTSCTS(tty)) {
 		ctl_hs |= CP210X_SERIAL_CTS_HANDSHAKE;
@@ -1172,7 +1177,10 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
 	} else {
 		ctl_hs &= ~CP210X_SERIAL_CTS_HANDSHAKE;
 		flow_repl &= ~CP210X_SERIAL_RTS_MASK;
-		flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_ACTIVE);
+		if (port_priv->rts)
+			flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_ACTIVE);
+		else
+			flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_INACTIVE);
 		port_priv->crtscts = false;
 	}
 
@@ -1287,25 +1295,29 @@ static int cp210x_tiocmset_port(struct usb_serial_port *port,
 	u16 control = 0;
 	int ret;
 
+	mutex_lock(&port_priv->mutex);
+
 	if (set & TIOCM_RTS) {
+		port_priv->rts = true;
 		control |= CONTROL_RTS;
 		control |= CONTROL_WRITE_RTS;
 	}
 	if (set & TIOCM_DTR) {
+		port_priv->dtr = true;
 		control |= CONTROL_DTR;
 		control |= CONTROL_WRITE_DTR;
 	}
 	if (clear & TIOCM_RTS) {
+		port_priv->rts = false;
 		control &= ~CONTROL_RTS;
 		control |= CONTROL_WRITE_RTS;
 	}
 	if (clear & TIOCM_DTR) {
+		port_priv->dtr = false;
 		control &= ~CONTROL_DTR;
 		control |= CONTROL_WRITE_DTR;
 	}
 
-	mutex_lock(&port_priv->mutex);
-
 	/*
 	 * SET_MHS cannot be used to control RTS when auto-RTS is enabled.
 	 * Note that RTS is still deasserted when disabling the UART on close.

From 568400b15a5145cb5d1479ece14e7b6d3a3cb554 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 25 Jan 2021 14:48:13 +0100
Subject: [PATCH 31/41] USB: serial: cp210x: drop shift macros

Drop the macros used to shift the flow-control settings to make the code
more readable for consistency with the other requests.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/cp210x.c | 28 +++++++++++-----------------
 1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 9378b4bba34b..aa874641374a 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -449,17 +449,14 @@ struct cp210x_flow_ctl {
 
 /* cp210x_flow_ctl::ulControlHandshake */
 #define CP210X_SERIAL_DTR_MASK		GENMASK(1, 0)
-#define CP210X_SERIAL_DTR_SHIFT(_mode)	(_mode)
+#define CP210X_SERIAL_DTR_INACTIVE	(0 << 0)
+#define CP210X_SERIAL_DTR_ACTIVE	(1 << 0)
+#define CP210X_SERIAL_DTR_FLOW_CTL	(2 << 0)
 #define CP210X_SERIAL_CTS_HANDSHAKE	BIT(3)
 #define CP210X_SERIAL_DSR_HANDSHAKE	BIT(4)
 #define CP210X_SERIAL_DCD_HANDSHAKE	BIT(5)
 #define CP210X_SERIAL_DSR_SENSITIVITY	BIT(6)
 
-/* values for cp210x_flow_ctl::ulControlHandshake::CP210X_SERIAL_DTR_MASK */
-#define CP210X_SERIAL_DTR_INACTIVE	0
-#define CP210X_SERIAL_DTR_ACTIVE	1
-#define CP210X_SERIAL_DTR_FLOW_CTL	2
-
 /* cp210x_flow_ctl::ulFlowReplace */
 #define CP210X_SERIAL_AUTO_TRANSMIT	BIT(0)
 #define CP210X_SERIAL_AUTO_RECEIVE	BIT(1)
@@ -467,14 +464,11 @@ struct cp210x_flow_ctl {
 #define CP210X_SERIAL_NULL_STRIPPING	BIT(3)
 #define CP210X_SERIAL_BREAK_CHAR	BIT(4)
 #define CP210X_SERIAL_RTS_MASK		GENMASK(7, 6)
-#define CP210X_SERIAL_RTS_SHIFT(_mode)	(_mode << 6)
+#define CP210X_SERIAL_RTS_INACTIVE	(0 << 6)
+#define CP210X_SERIAL_RTS_ACTIVE	(1 << 6)
+#define CP210X_SERIAL_RTS_FLOW_CTL	(2 << 6)
 #define CP210X_SERIAL_XOFF_CONTINUE	BIT(31)
 
-/* values for cp210x_flow_ctl::ulFlowReplace::CP210X_SERIAL_RTS_MASK */
-#define CP210X_SERIAL_RTS_INACTIVE	0
-#define CP210X_SERIAL_RTS_ACTIVE	1
-#define CP210X_SERIAL_RTS_FLOW_CTL	2
-
 /* CP210X_VENDOR_SPECIFIC, CP210X_GET_DEVICEMODE call reads these 0x2 bytes. */
 struct cp210x_pin_mode {
 	u8	eci;
@@ -1165,22 +1159,22 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
 	ctl_hs &= ~CP210X_SERIAL_DSR_SENSITIVITY;
 	ctl_hs &= ~CP210X_SERIAL_DTR_MASK;
 	if (port_priv->dtr)
-		ctl_hs |= CP210X_SERIAL_DTR_SHIFT(CP210X_SERIAL_DTR_ACTIVE);
+		ctl_hs |= CP210X_SERIAL_DTR_ACTIVE;
 	else
-		ctl_hs |= CP210X_SERIAL_DTR_SHIFT(CP210X_SERIAL_DTR_INACTIVE);
+		ctl_hs |= CP210X_SERIAL_DTR_INACTIVE;
 
 	if (C_CRTSCTS(tty)) {
 		ctl_hs |= CP210X_SERIAL_CTS_HANDSHAKE;
 		flow_repl &= ~CP210X_SERIAL_RTS_MASK;
-		flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_FLOW_CTL);
+		flow_repl |= CP210X_SERIAL_RTS_FLOW_CTL;
 		port_priv->crtscts = true;
 	} else {
 		ctl_hs &= ~CP210X_SERIAL_CTS_HANDSHAKE;
 		flow_repl &= ~CP210X_SERIAL_RTS_MASK;
 		if (port_priv->rts)
-			flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_ACTIVE);
+			flow_repl |= CP210X_SERIAL_RTS_ACTIVE;
 		else
-			flow_repl |= CP210X_SERIAL_RTS_SHIFT(CP210X_SERIAL_RTS_INACTIVE);
+			flow_repl |= CP210X_SERIAL_RTS_INACTIVE;
 		port_priv->crtscts = false;
 	}
 

From f191c63779a0debf2a7f85a5c8d0c09d35b50ddb Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 25 Jan 2021 14:48:14 +0100
Subject: [PATCH 32/41] USB: serial: cp210x: clean up flow-control debug
 message

Shorten the flow-control debug message by abbreviating the field names
and reducing the value width to two characters. The latter improves
readability since all but the least significant byte will almost always
be zero anyway.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/cp210x.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index aa874641374a..36ae44818c13 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -1191,8 +1191,8 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
 	flow_ctl.ulXonLimit = cpu_to_le32(128);
 	flow_ctl.ulXoffLimit = cpu_to_le32(128);
 
-	dev_dbg(&port->dev, "%s - ulControlHandshake=0x%08x, ulFlowReplace=0x%08x\n",
-			__func__, ctl_hs, flow_repl);
+	dev_dbg(&port->dev, "%s - ctrl = 0x%02x, flow = 0x%02x\n", __func__,
+			ctl_hs, flow_repl);
 
 	flow_ctl.ulControlHandshake = cpu_to_le32(ctl_hs);
 	flow_ctl.ulFlowReplace = cpu_to_le32(flow_repl);

From 6b667274f41a0269a8b493079fcacd4f55183f60 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 25 Jan 2021 14:48:15 +0100
Subject: [PATCH 33/41] USB: serial: cp210x: clean up printk zero padding

Use the 0-flag and a field width to specify zero-padding consistently in
printk messages.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/cp210x.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 36ae44818c13..4ba3fb096bf1 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -1319,7 +1319,7 @@ static int cp210x_tiocmset_port(struct usb_serial_port *port,
 	if (port_priv->crtscts)
 		control &= ~CONTROL_WRITE_RTS;
 
-	dev_dbg(&port->dev, "%s - control = 0x%.4x\n", __func__, control);
+	dev_dbg(&port->dev, "%s - control = 0x%04x\n", __func__, control);
 
 	ret = cp210x_write_u16_reg(port, CP210X_SET_MHS, control);
 
@@ -1353,7 +1353,7 @@ static int cp210x_tiocmget(struct tty_struct *tty)
 		|((control & CONTROL_RING)? TIOCM_RI  : 0)
 		|((control & CONTROL_DCD) ? TIOCM_CD  : 0);
 
-	dev_dbg(&port->dev, "%s - control = 0x%.2x\n", __func__, control);
+	dev_dbg(&port->dev, "%s - control = 0x%02x\n", __func__, control);
 
 	return result;
 }

From cf00ead0bde8e47ccd3aa8a4e51cfa59bbf5e055 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 25 Jan 2021 14:48:16 +0100
Subject: [PATCH 34/41] USB: serial: cp210x: fix RTS handling

Clearing TIOCM_RTS should always deassert RTS and setting the same bit
should enable auto-RTS if hardware flow control is enabled.

This allows user space to throttle input directly at the source also
when hardware-assisted flow control is enabled and makes dtr_rts()
always deassert both lines during close (when HUPCL is set).

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/cp210x.c | 47 +++++++++++++++++++++++++++++++------
 1 file changed, 40 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 4ba3fb096bf1..f00b736f3cd3 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -1166,7 +1166,10 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
 	if (C_CRTSCTS(tty)) {
 		ctl_hs |= CP210X_SERIAL_CTS_HANDSHAKE;
 		flow_repl &= ~CP210X_SERIAL_RTS_MASK;
-		flow_repl |= CP210X_SERIAL_RTS_FLOW_CTL;
+		if (port_priv->rts)
+			flow_repl |= CP210X_SERIAL_RTS_FLOW_CTL;
+		else
+			flow_repl |= CP210X_SERIAL_RTS_INACTIVE;
 		port_priv->crtscts = true;
 	} else {
 		ctl_hs &= ~CP210X_SERIAL_CTS_HANDSHAKE;
@@ -1286,6 +1289,8 @@ static int cp210x_tiocmset_port(struct usb_serial_port *port,
 		unsigned int set, unsigned int clear)
 {
 	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
+	struct cp210x_flow_ctl flow_ctl;
+	u32 ctl_hs, flow_repl;
 	u16 control = 0;
 	int ret;
 
@@ -1313,16 +1318,44 @@ static int cp210x_tiocmset_port(struct usb_serial_port *port,
 	}
 
 	/*
-	 * SET_MHS cannot be used to control RTS when auto-RTS is enabled.
-	 * Note that RTS is still deasserted when disabling the UART on close.
+	 * Use SET_FLOW to set DTR and enable/disable auto-RTS when hardware
+	 * flow control is enabled.
 	 */
-	if (port_priv->crtscts)
-		control &= ~CONTROL_WRITE_RTS;
+	if (port_priv->crtscts && control & CONTROL_WRITE_RTS) {
+		ret = cp210x_read_reg_block(port, CP210X_GET_FLOW, &flow_ctl,
+				sizeof(flow_ctl));
+		if (ret)
+			goto out_unlock;
 
-	dev_dbg(&port->dev, "%s - control = 0x%04x\n", __func__, control);
+		ctl_hs = le32_to_cpu(flow_ctl.ulControlHandshake);
+		flow_repl = le32_to_cpu(flow_ctl.ulFlowReplace);
 
-	ret = cp210x_write_u16_reg(port, CP210X_SET_MHS, control);
+		ctl_hs &= ~CP210X_SERIAL_DTR_MASK;
+		if (port_priv->dtr)
+			ctl_hs |= CP210X_SERIAL_DTR_ACTIVE;
+		else
+			ctl_hs |= CP210X_SERIAL_DTR_INACTIVE;
 
+		flow_repl &= ~CP210X_SERIAL_RTS_MASK;
+		if (port_priv->rts)
+			flow_repl |= CP210X_SERIAL_RTS_FLOW_CTL;
+		else
+			flow_repl |= CP210X_SERIAL_RTS_INACTIVE;
+
+		flow_ctl.ulControlHandshake = cpu_to_le32(ctl_hs);
+		flow_ctl.ulFlowReplace = cpu_to_le32(flow_repl);
+
+		dev_dbg(&port->dev, "%s - ctrl = 0x%02x, flow = 0x%02x\n",
+				__func__, ctl_hs, flow_repl);
+
+		ret = cp210x_write_reg_block(port, CP210X_SET_FLOW, &flow_ctl,
+				sizeof(flow_ctl));
+	} else {
+		dev_dbg(&port->dev, "%s - control = 0x%04x\n", __func__, control);
+
+		ret = cp210x_write_u16_reg(port, CP210X_SET_MHS, control);
+	}
+out_unlock:
 	mutex_unlock(&port_priv->mutex);
 
 	return ret;

From e2f2dea34cf16e67b347ea7e9805864f03d16dcc Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 25 Jan 2021 14:48:17 +0100
Subject: [PATCH 35/41] USB: serial: cp210x: clean up auto-RTS handling

Clear the RTS bits of the flow-control request before determining the
new value when updating the settings.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/cp210x.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index f00b736f3cd3..cc4f63a06f9e 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -1163,9 +1163,9 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
 	else
 		ctl_hs |= CP210X_SERIAL_DTR_INACTIVE;
 
+	flow_repl &= ~CP210X_SERIAL_RTS_MASK;
 	if (C_CRTSCTS(tty)) {
 		ctl_hs |= CP210X_SERIAL_CTS_HANDSHAKE;
-		flow_repl &= ~CP210X_SERIAL_RTS_MASK;
 		if (port_priv->rts)
 			flow_repl |= CP210X_SERIAL_RTS_FLOW_CTL;
 		else
@@ -1173,7 +1173,6 @@ static void cp210x_set_flow_control(struct tty_struct *tty,
 		port_priv->crtscts = true;
 	} else {
 		ctl_hs &= ~CP210X_SERIAL_CTS_HANDSHAKE;
-		flow_repl &= ~CP210X_SERIAL_RTS_MASK;
 		if (port_priv->rts)
 			flow_repl |= CP210X_SERIAL_RTS_ACTIVE;
 		else

From 528222d0c8ce93e435a95cd1e476b60409dd5381 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Tue, 26 Jan 2021 14:59:17 +0100
Subject: [PATCH 36/41] USB: serial: ftdi_sio: fix FTX sub-integer prescaler

The most-significant bit of the sub-integer-prescaler index is set in
the high byte of the baudrate request wIndex also for FTX devices.

This fixes rates like 1152000 which got mapped to 1.2 MBd.

Reported-by: Vladimir <svv75@mail.ru>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=210351
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/ftdi_sio.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 94398f89e600..4168801b9595 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -1386,8 +1386,9 @@ static int change_speed(struct tty_struct *tty, struct usb_serial_port *port)
 	index_value = get_ftdi_divisor(tty, port);
 	value = (u16)index_value;
 	index = (u16)(index_value >> 16);
-	if ((priv->chip_type == FT2232C) || (priv->chip_type == FT2232H) ||
-		(priv->chip_type == FT4232H) || (priv->chip_type == FT232H)) {
+	if (priv->chip_type == FT2232C || priv->chip_type == FT2232H ||
+			priv->chip_type == FT4232H || priv->chip_type == FT232H ||
+			priv->chip_type == FTX) {
 		/* Probably the BM type needs the MSB of the encoded fractional
 		 * divider also moved like for the chips above. Any infos? */
 		index = (u16)((index << 8) | priv->interface);

From 1ef268039b79945a9284dbc34eedcbad21415106 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Wed, 27 Jan 2021 12:00:28 +0100
Subject: [PATCH 37/41] USB: serial: ftdi_sio: restore divisor-encoding
 comments

Add back a few explanatory comments related to the divisor encoding
which got lost in a coding-style clean up many years ago.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/ftdi_sio.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 4168801b9595..d61703d858a1 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -1153,13 +1153,13 @@ static unsigned short int ftdi_232am_baud_base_to_divisor(int baud, int base)
 	divisor = divisor3 >> 3;
 	divisor3 &= 0x7;
 	if (divisor3 == 1)
-		divisor |= 0xc000;
+		divisor |= 0xc000;	/* +0.125 */
 	else if (divisor3 >= 4)
-		divisor |= 0x4000;
+		divisor |= 0x4000;	/* +0.5 */
 	else if (divisor3 != 0)
-		divisor |= 0x8000;
+		divisor |= 0x8000;	/* +0.25 */
 	else if (divisor == 1)
-		divisor = 0;	/* special case for maximum baud rate */
+		divisor = 0;		/* special case for maximum baud rate */
 	return divisor;
 }
 
@@ -1177,9 +1177,9 @@ static u32 ftdi_232bm_baud_base_to_divisor(int baud, int base)
 	divisor = divisor3 >> 3;
 	divisor |= (u32)divfrac[divisor3 & 0x7] << 14;
 	/* Deal with special cases for highest baud rates. */
-	if (divisor == 1)
+	if (divisor == 1)		/* 1.0 */
 		divisor = 0;
-	else if (divisor == 0x4001)
+	else if (divisor == 0x4001)	/* 1.5 */
 		divisor = 1;
 	return divisor;
 }
@@ -1201,9 +1201,9 @@ static u32 ftdi_2232h_baud_base_to_divisor(int baud, int base)
 	divisor = divisor3 >> 3;
 	divisor |= (u32)divfrac[divisor3 & 0x7] << 14;
 	/* Deal with special cases for highest baud rates. */
-	if (divisor == 1)
+	if (divisor == 1)		/* 1.0 */
 		divisor = 0;
-	else if (divisor == 0x4001)
+	else if (divisor == 0x4001)	/* 1.5 */
 		divisor = 1;
 	/*
 	 * Set this bit to turn off a divide by 2.5 on baud rate generator

From 6420a569504e212d618d4a4736e2c59ed80a8478 Mon Sep 17 00:00:00 2001
From: Lech Perczak <lech.perczak@gmail.com>
Date: Sun, 7 Feb 2021 01:54:43 +0100
Subject: [PATCH 38/41] USB: serial: option: update interface mapping for ZTE
 P685M
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This patch prepares for qmi_wwan driver support for the device.
Previously "option" driver mapped itself to interfaces 0 and 3 (matching
ff/ff/ff), while interface 3 is in fact a QMI port.
Interfaces 1 and 2 (matching ff/00/00) expose AT commands,
and weren't supported previously at all.
Without this patch, a possible conflict would exist if device ID was
added to qmi_wwan driver for interface 3.

Update and simplify device ID to match interfaces 0-2 directly,
to expose QCDM (0), PCUI (1), and modem (2) ports and avoid conflict
with QMI (3), and ADB (4).

The modem is used inside ZTE MF283+ router and carriers identify it as
such.
Interface mapping is:
0: QCDM, 1: AT (PCUI), 2: AT (Modem), 3: QMI, 4: ADB

T:  Bus=02 Lev=02 Prnt=02 Port=05 Cnt=01 Dev#=  3 Spd=480  MxCh= 0
D:  Ver= 2.01 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=19d2 ProdID=1275 Rev=f0.00
S:  Manufacturer=ZTE,Incorporated
S:  Product=ZTE Technologies MSM
S:  SerialNumber=P685M510ZTED0000CP&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&0
C:* #Ifs= 5 Cfg#= 1 Atr=a0 MxPwr=500mA
I:* If#= 0 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=option
E:  Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=01(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 1 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
E:  Ad=83(I) Atr=03(Int.) MxPS=  10 Ivl=32ms
E:  Ad=82(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 2 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=option
E:  Ad=85(I) Atr=03(Int.) MxPS=  10 Ivl=32ms
E:  Ad=84(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=03(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 3 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=qmi_wwan
E:  Ad=87(I) Atr=03(Int.) MxPS=   8 Ivl=32ms
E:  Ad=86(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=04(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I:* If#= 4 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=42 Prot=01 Driver=(none)
E:  Ad=88(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=05(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms

Cc: Johan Hovold <johan@kernel.org>
Cc: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Lech Perczak <lech.perczak@gmail.com>
Link: https://lore.kernel.org/r/20210207005443.12936-1-lech.perczak@gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/option.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/serial/option.c b/drivers/usb/serial/option.c
index 3fe959104311..6716dfcf2610 100644
--- a/drivers/usb/serial/option.c
+++ b/drivers/usb/serial/option.c
@@ -1567,7 +1567,8 @@ static const struct usb_device_id option_ids[] = {
 	{ USB_DEVICE_AND_INTERFACE_INFO(ZTE_VENDOR_ID, 0x1272, 0xff, 0xff, 0xff) },
 	{ USB_DEVICE_AND_INTERFACE_INFO(ZTE_VENDOR_ID, 0x1273, 0xff, 0xff, 0xff) },
 	{ USB_DEVICE_AND_INTERFACE_INFO(ZTE_VENDOR_ID, 0x1274, 0xff, 0xff, 0xff) },
-	{ USB_DEVICE_AND_INTERFACE_INFO(ZTE_VENDOR_ID, 0x1275, 0xff, 0xff, 0xff) },
+	{ USB_DEVICE(ZTE_VENDOR_ID, 0x1275),	/* ZTE P685M */
+	  .driver_info = RSVD(3) | RSVD(4) },
 	{ USB_DEVICE_AND_INTERFACE_INFO(ZTE_VENDOR_ID, 0x1276, 0xff, 0xff, 0xff) },
 	{ USB_DEVICE_AND_INTERFACE_INFO(ZTE_VENDOR_ID, 0x1277, 0xff, 0xff, 0xff) },
 	{ USB_DEVICE_AND_INTERFACE_INFO(ZTE_VENDOR_ID, 0x1278, 0xff, 0xff, 0xff) },

From a54af1b7d667927162d13083a8e2d470fb8722e2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <uwe@kleine-koenig.org>
Date: Mon, 8 Feb 2021 15:31:48 +0100
Subject: [PATCH 39/41] USB: serial: drop if with an always false condition
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

In a bus remove function the passed device is always valid, so there is
no need to check for it being NULL.

(Side note: The check for port being non-NULL is broken anyhow, because
to_usb_serial_port() is a wrapper around container_of() for a member that is
not the first one. So port can hardly become NULL.)

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Link: https://lore.kernel.org/r/20210208143149.963644-1-uwe@kleine-koenig.org
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/bus.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/usb/serial/bus.c b/drivers/usb/serial/bus.c
index eb0195cf37dd..58206ef0a780 100644
--- a/drivers/usb/serial/bus.c
+++ b/drivers/usb/serial/bus.c
@@ -86,16 +86,12 @@ err_autopm_put:
 
 static int usb_serial_device_remove(struct device *dev)
 {
+	struct usb_serial_port *port = to_usb_serial_port(dev);
 	struct usb_serial_driver *driver;
-	struct usb_serial_port *port;
 	int retval = 0;
 	int minor;
 	int autopm_err;
 
-	port = to_usb_serial_port(dev);
-	if (!port)
-		return -ENODEV;
-
 	/*
 	 * Make sure suspend/resume doesn't race against port_remove.
 	 *

From c5d1448fa353242635fa3e1fed6ab4558e0e7d9a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <uwe@kleine-koenig.org>
Date: Mon, 8 Feb 2021 15:31:49 +0100
Subject: [PATCH 40/41] USB: serial: make remove callback return void
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

All usb_serial drivers return 0 in their remove callbacks and driver
core ignores the value returned by usb_serial_device_remove(). So change
the remove callback to return void and return 0 unconditionally in
usb_serial_device_remove().

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Link: https://lore.kernel.org/r/20210208143149.963644-2-uwe@kleine-koenig.org
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/ark3116.c          | 4 +---
 drivers/usb/serial/belkin_sa.c        | 6 ++----
 drivers/usb/serial/bus.c              | 5 ++---
 drivers/usb/serial/ch341.c            | 4 +---
 drivers/usb/serial/cp210x.c           | 6 ++----
 drivers/usb/serial/cyberjack.c        | 6 ++----
 drivers/usb/serial/cypress_m8.c       | 6 ++----
 drivers/usb/serial/digi_acceleport.c  | 6 ++----
 drivers/usb/serial/f81534.c           | 3 +--
 drivers/usb/serial/ftdi_sio.c         | 6 ++----
 drivers/usb/serial/garmin_gps.c       | 3 +--
 drivers/usb/serial/io_edgeport.c      | 6 ++----
 drivers/usb/serial/io_ti.c            | 4 +---
 drivers/usb/serial/iuu_phoenix.c      | 4 +---
 drivers/usb/serial/keyspan.c          | 6 ++----
 drivers/usb/serial/keyspan_pda.c      | 4 +---
 drivers/usb/serial/kl5kusb105.c       | 6 ++----
 drivers/usb/serial/kobil_sct.c        | 6 ++----
 drivers/usb/serial/mct_u232.c         | 6 ++----
 drivers/usb/serial/metro-usb.c        | 4 +---
 drivers/usb/serial/mos7720.c          | 4 +---
 drivers/usb/serial/mos7840.c          | 4 +---
 drivers/usb/serial/omninet.c          | 6 ++----
 drivers/usb/serial/opticon.c          | 4 +---
 drivers/usb/serial/oti6858.c          | 6 ++----
 drivers/usb/serial/pl2303.c           | 4 +---
 drivers/usb/serial/quatech2.c         | 4 +---
 drivers/usb/serial/sierra.c           | 4 +---
 drivers/usb/serial/spcp8x5.c          | 4 +---
 drivers/usb/serial/ssu100.c           | 4 +---
 drivers/usb/serial/symbolserial.c     | 4 +---
 drivers/usb/serial/ti_usb_3410_5052.c | 6 ++----
 drivers/usb/serial/upd78f0730.c       | 4 +---
 drivers/usb/serial/usb-wwan.h         | 2 +-
 drivers/usb/serial/usb_wwan.c         | 4 +---
 drivers/usb/serial/whiteheat.c        | 6 ++----
 include/linux/usb/serial.h            | 2 +-
 37 files changed, 53 insertions(+), 120 deletions(-)

diff --git a/drivers/usb/serial/ark3116.c b/drivers/usb/serial/ark3116.c
index 71a9206ea1e2..f0ac7bb07ac1 100644
--- a/drivers/usb/serial/ark3116.c
+++ b/drivers/usb/serial/ark3116.c
@@ -178,15 +178,13 @@ static int ark3116_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int ark3116_port_remove(struct usb_serial_port *port)
+static void ark3116_port_remove(struct usb_serial_port *port)
 {
 	struct ark3116_private *priv = usb_get_serial_port_data(port);
 
 	/* device is closed, so URBs and DMA should be down */
 	mutex_destroy(&priv->hw_lock);
 	kfree(priv);
-
-	return 0;
 }
 
 static void ark3116_set_termios(struct tty_struct *tty,
diff --git a/drivers/usb/serial/belkin_sa.c b/drivers/usb/serial/belkin_sa.c
index 9bb123ab9bc9..ed9193f3bb1a 100644
--- a/drivers/usb/serial/belkin_sa.c
+++ b/drivers/usb/serial/belkin_sa.c
@@ -37,7 +37,7 @@
 
 /* function prototypes for a Belkin USB Serial Adapter F5U103 */
 static int belkin_sa_port_probe(struct usb_serial_port *port);
-static int belkin_sa_port_remove(struct usb_serial_port *port);
+static void belkin_sa_port_remove(struct usb_serial_port *port);
 static int  belkin_sa_open(struct tty_struct *tty,
 			struct usb_serial_port *port);
 static void belkin_sa_close(struct usb_serial_port *port);
@@ -134,14 +134,12 @@ static int belkin_sa_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int belkin_sa_port_remove(struct usb_serial_port *port)
+static void belkin_sa_port_remove(struct usb_serial_port *port)
 {
 	struct belkin_sa_private *priv;
 
 	priv = usb_get_serial_port_data(port);
 	kfree(priv);
-
-	return 0;
 }
 
 static int belkin_sa_open(struct tty_struct *tty,
diff --git a/drivers/usb/serial/bus.c b/drivers/usb/serial/bus.c
index 58206ef0a780..1a8c7821d00a 100644
--- a/drivers/usb/serial/bus.c
+++ b/drivers/usb/serial/bus.c
@@ -88,7 +88,6 @@ static int usb_serial_device_remove(struct device *dev)
 {
 	struct usb_serial_port *port = to_usb_serial_port(dev);
 	struct usb_serial_driver *driver;
-	int retval = 0;
 	int minor;
 	int autopm_err;
 
@@ -105,7 +104,7 @@ static int usb_serial_device_remove(struct device *dev)
 
 	driver = port->serial->type;
 	if (driver->port_remove)
-		retval = driver->port_remove(port);
+		driver->port_remove(port);
 
 	dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
 		 driver->description, minor);
@@ -113,7 +112,7 @@ static int usb_serial_device_remove(struct device *dev)
 	if (!autopm_err)
 		usb_autopm_put_interface(port->serial->interface);
 
-	return retval;
+	return 0;
 }
 
 static ssize_t new_id_store(struct device_driver *driver,
diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 28deaaec581f..8d997b71056f 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -419,14 +419,12 @@ error:	kfree(priv);
 	return r;
 }
 
-static int ch341_port_remove(struct usb_serial_port *port)
+static void ch341_port_remove(struct usb_serial_port *port)
 {
 	struct ch341_private *priv;
 
 	priv = usb_get_serial_port_data(port);
 	kfree(priv);
-
-	return 0;
 }
 
 static int ch341_carrier_raised(struct usb_serial_port *port)
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index cc4f63a06f9e..665798043d3c 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -44,7 +44,7 @@ static int cp210x_attach(struct usb_serial *);
 static void cp210x_disconnect(struct usb_serial *);
 static void cp210x_release(struct usb_serial *);
 static int cp210x_port_probe(struct usb_serial_port *);
-static int cp210x_port_remove(struct usb_serial_port *);
+static void cp210x_port_remove(struct usb_serial_port *);
 static void cp210x_dtr_rts(struct usb_serial_port *port, int on);
 static void cp210x_process_read_urb(struct urb *urb);
 static void cp210x_enable_event_mode(struct usb_serial_port *port);
@@ -1841,14 +1841,12 @@ static int cp210x_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int cp210x_port_remove(struct usb_serial_port *port)
+static void cp210x_port_remove(struct usb_serial_port *port)
 {
 	struct cp210x_port_private *port_priv;
 
 	port_priv = usb_get_serial_port_data(port);
 	kfree(port_priv);
-
-	return 0;
 }
 
 static void cp210x_init_max_speed(struct usb_serial *serial)
diff --git a/drivers/usb/serial/cyberjack.c b/drivers/usb/serial/cyberjack.c
index 2e40908963da..cf389224d528 100644
--- a/drivers/usb/serial/cyberjack.c
+++ b/drivers/usb/serial/cyberjack.c
@@ -47,7 +47,7 @@
 
 /* Function prototypes */
 static int cyberjack_port_probe(struct usb_serial_port *port);
-static int cyberjack_port_remove(struct usb_serial_port *port);
+static void cyberjack_port_remove(struct usb_serial_port *port);
 static int  cyberjack_open(struct tty_struct *tty,
 	struct usb_serial_port *port);
 static void cyberjack_close(struct usb_serial_port *port);
@@ -120,7 +120,7 @@ static int cyberjack_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int cyberjack_port_remove(struct usb_serial_port *port)
+static void cyberjack_port_remove(struct usb_serial_port *port)
 {
 	struct cyberjack_private *priv;
 
@@ -128,8 +128,6 @@ static int cyberjack_port_remove(struct usb_serial_port *port)
 
 	priv = usb_get_serial_port_data(port);
 	kfree(priv);
-
-	return 0;
 }
 
 static int  cyberjack_open(struct tty_struct *tty,
diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index cc028601c388..166ee2286fda 100644
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -115,7 +115,7 @@ struct cypress_private {
 static int  cypress_earthmate_port_probe(struct usb_serial_port *port);
 static int  cypress_hidcom_port_probe(struct usb_serial_port *port);
 static int  cypress_ca42v2_port_probe(struct usb_serial_port *port);
-static int  cypress_port_remove(struct usb_serial_port *port);
+static void cypress_port_remove(struct usb_serial_port *port);
 static int  cypress_open(struct tty_struct *tty, struct usb_serial_port *port);
 static void cypress_close(struct usb_serial_port *port);
 static void cypress_dtr_rts(struct usb_serial_port *port, int on);
@@ -564,7 +564,7 @@ static int cypress_ca42v2_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int cypress_port_remove(struct usb_serial_port *port)
+static void cypress_port_remove(struct usb_serial_port *port)
 {
 	struct cypress_private *priv;
 
@@ -572,8 +572,6 @@ static int cypress_port_remove(struct usb_serial_port *port)
 
 	kfifo_free(&priv->write_fifo);
 	kfree(priv);
-
-	return 0;
 }
 
 static int cypress_open(struct tty_struct *tty, struct usb_serial_port *port)
diff --git a/drivers/usb/serial/digi_acceleport.c b/drivers/usb/serial/digi_acceleport.c
index 0ecd5316d85f..8b2f06539f2c 100644
--- a/drivers/usb/serial/digi_acceleport.c
+++ b/drivers/usb/serial/digi_acceleport.c
@@ -233,7 +233,7 @@ static int digi_startup(struct usb_serial *serial);
 static void digi_disconnect(struct usb_serial *serial);
 static void digi_release(struct usb_serial *serial);
 static int digi_port_probe(struct usb_serial_port *port);
-static int digi_port_remove(struct usb_serial_port *port);
+static void digi_port_remove(struct usb_serial_port *port);
 static void digi_read_bulk_callback(struct urb *urb);
 static int digi_read_inb_callback(struct urb *urb);
 static int digi_read_oob_callback(struct urb *urb);
@@ -1281,14 +1281,12 @@ static int digi_port_probe(struct usb_serial_port *port)
 	return digi_port_init(port, port->port_number);
 }
 
-static int digi_port_remove(struct usb_serial_port *port)
+static void digi_port_remove(struct usb_serial_port *port)
 {
 	struct digi_port *priv;
 
 	priv = usb_get_serial_port_data(port);
 	kfree(priv);
-
-	return 0;
 }
 
 static void digi_read_bulk_callback(struct urb *urb)
diff --git a/drivers/usb/serial/f81534.c b/drivers/usb/serial/f81534.c
index dd7e55e822ef..a763b362f081 100644
--- a/drivers/usb/serial/f81534.c
+++ b/drivers/usb/serial/f81534.c
@@ -1430,12 +1430,11 @@ static int f81534_port_probe(struct usb_serial_port *port)
 	return f81534_set_port_output_pin(port);
 }
 
-static int f81534_port_remove(struct usb_serial_port *port)
+static void f81534_port_remove(struct usb_serial_port *port)
 {
 	struct f81534_port_private *port_priv = usb_get_serial_port_data(port);
 
 	flush_work(&port_priv->lsr_work);
-	return 0;
 }
 
 static int f81534_tiocmget(struct tty_struct *tty)
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index d61703d858a1..c867592477c9 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -1069,7 +1069,7 @@ static const char *ftdi_chip_name[] = {
 static int  ftdi_sio_probe(struct usb_serial *serial,
 					const struct usb_device_id *id);
 static int  ftdi_sio_port_probe(struct usb_serial_port *port);
-static int  ftdi_sio_port_remove(struct usb_serial_port *port);
+static void ftdi_sio_port_remove(struct usb_serial_port *port);
 static int  ftdi_open(struct tty_struct *tty, struct usb_serial_port *port);
 static void ftdi_dtr_rts(struct usb_serial_port *port, int on);
 static void ftdi_process_read_urb(struct urb *urb);
@@ -2400,7 +2400,7 @@ static int ftdi_stmclite_probe(struct usb_serial *serial)
 	return 0;
 }
 
-static int ftdi_sio_port_remove(struct usb_serial_port *port)
+static void ftdi_sio_port_remove(struct usb_serial_port *port)
 {
 	struct ftdi_private *priv = usb_get_serial_port_data(port);
 
@@ -2409,8 +2409,6 @@ static int ftdi_sio_port_remove(struct usb_serial_port *port)
 	remove_sysfs_attrs(port);
 
 	kfree(priv);
-
-	return 0;
 }
 
 static int ftdi_open(struct tty_struct *tty, struct usb_serial_port *port)
diff --git a/drivers/usb/serial/garmin_gps.c b/drivers/usb/serial/garmin_gps.c
index c02c19bb1183..50e8bdc77e71 100644
--- a/drivers/usb/serial/garmin_gps.c
+++ b/drivers/usb/serial/garmin_gps.c
@@ -1401,7 +1401,7 @@ err_free:
 }
 
 
-static int garmin_port_remove(struct usb_serial_port *port)
+static void garmin_port_remove(struct usb_serial_port *port)
 {
 	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
 
@@ -1409,7 +1409,6 @@ static int garmin_port_remove(struct usb_serial_port *port)
 	usb_kill_urb(port->interrupt_in_urb);
 	del_timer_sync(&garmin_data_p->timer);
 	kfree(garmin_data_p);
-	return 0;
 }
 
 
diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
index ba5d8df69518..a493670c06e6 100644
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -293,7 +293,7 @@ static int  edge_startup(struct usb_serial *serial);
 static void edge_disconnect(struct usb_serial *serial);
 static void edge_release(struct usb_serial *serial);
 static int edge_port_probe(struct usb_serial_port *port);
-static int edge_port_remove(struct usb_serial_port *port);
+static void edge_port_remove(struct usb_serial_port *port);
 
 /* function prototypes for all of our local functions */
 
@@ -3078,14 +3078,12 @@ static int edge_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int edge_port_remove(struct usb_serial_port *port)
+static void edge_port_remove(struct usb_serial_port *port)
 {
 	struct edgeport_port *edge_port;
 
 	edge_port = usb_get_serial_port_data(port);
 	kfree(edge_port);
-
-	return 0;
 }
 
 static struct usb_serial_driver edgeport_2port_device = {
diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index 0bbfa47e04b7..e800547be9e0 100644
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -2625,15 +2625,13 @@ err:
 	return ret;
 }
 
-static int edge_port_remove(struct usb_serial_port *port)
+static void edge_port_remove(struct usb_serial_port *port)
 {
 	struct edgeport_port *edge_port;
 
 	edge_port = usb_get_serial_port_data(port);
 	edge_remove_sysfs_attrs(port);
 	kfree(edge_port);
-
-	return 0;
 }
 
 /* Sysfs Attributes */
diff --git a/drivers/usb/serial/iuu_phoenix.c b/drivers/usb/serial/iuu_phoenix.c
index e8f06b41a503..093afd67a664 100644
--- a/drivers/usb/serial/iuu_phoenix.c
+++ b/drivers/usb/serial/iuu_phoenix.c
@@ -100,7 +100,7 @@ static int iuu_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int iuu_port_remove(struct usb_serial_port *port)
+static void iuu_port_remove(struct usb_serial_port *port)
 {
 	struct iuu_private *priv = usb_get_serial_port_data(port);
 
@@ -108,8 +108,6 @@ static int iuu_port_remove(struct usb_serial_port *port)
 	kfree(priv->writebuf);
 	kfree(priv->buf);
 	kfree(priv);
-
-	return 0;
 }
 
 static int iuu_tiocmset(struct tty_struct *tty,
diff --git a/drivers/usb/serial/keyspan.c b/drivers/usb/serial/keyspan.c
index aa3dbce22cfb..622077dcc344 100644
--- a/drivers/usb/serial/keyspan.c
+++ b/drivers/usb/serial/keyspan.c
@@ -49,7 +49,7 @@ static int keyspan_startup(struct usb_serial *serial);
 static void keyspan_disconnect(struct usb_serial *serial);
 static void keyspan_release(struct usb_serial *serial);
 static int keyspan_port_probe(struct usb_serial_port *port);
-static int keyspan_port_remove(struct usb_serial_port *port);
+static void keyspan_port_remove(struct usb_serial_port *port);
 static int keyspan_write_room(struct tty_struct *tty);
 static int keyspan_write(struct tty_struct *tty, struct usb_serial_port *port,
 			 const unsigned char *buf, int count);
@@ -2985,7 +2985,7 @@ err_in_buffer:
 	return -ENOMEM;
 }
 
-static int keyspan_port_remove(struct usb_serial_port *port)
+static void keyspan_port_remove(struct usb_serial_port *port)
 {
 	struct keyspan_port_private *p_priv;
 	int i;
@@ -3014,8 +3014,6 @@ static int keyspan_port_remove(struct usb_serial_port *port)
 		kfree(p_priv->in_buffer[i]);
 
 	kfree(p_priv);
-
-	return 0;
 }
 
 /* Structs for the devices, pre and post renumeration. */
diff --git a/drivers/usb/serial/keyspan_pda.c b/drivers/usb/serial/keyspan_pda.c
index e6f933e8d25f..39b0f5f344c2 100644
--- a/drivers/usb/serial/keyspan_pda.c
+++ b/drivers/usb/serial/keyspan_pda.c
@@ -672,14 +672,12 @@ static int keyspan_pda_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int keyspan_pda_port_remove(struct usb_serial_port *port)
+static void keyspan_pda_port_remove(struct usb_serial_port *port)
 {
 	struct keyspan_pda_private *priv;
 
 	priv = usb_get_serial_port_data(port);
 	kfree(priv);
-
-	return 0;
 }
 
 static struct usb_serial_driver keyspan_pda_fake_device = {
diff --git a/drivers/usb/serial/kl5kusb105.c b/drivers/usb/serial/kl5kusb105.c
index 5f6b82ebccc5..f1e9628a9907 100644
--- a/drivers/usb/serial/kl5kusb105.c
+++ b/drivers/usb/serial/kl5kusb105.c
@@ -52,7 +52,7 @@
  * Function prototypes
  */
 static int klsi_105_port_probe(struct usb_serial_port *port);
-static int klsi_105_port_remove(struct usb_serial_port *port);
+static void klsi_105_port_remove(struct usb_serial_port *port);
 static int  klsi_105_open(struct tty_struct *tty, struct usb_serial_port *port);
 static void klsi_105_close(struct usb_serial_port *port);
 static void klsi_105_set_termios(struct tty_struct *tty,
@@ -231,14 +231,12 @@ static int klsi_105_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int klsi_105_port_remove(struct usb_serial_port *port)
+static void klsi_105_port_remove(struct usb_serial_port *port)
 {
 	struct klsi_105_private *priv;
 
 	priv = usb_get_serial_port_data(port);
 	kfree(priv);
-
-	return 0;
 }
 
 static int  klsi_105_open(struct tty_struct *tty, struct usb_serial_port *port)
diff --git a/drivers/usb/serial/kobil_sct.c b/drivers/usb/serial/kobil_sct.c
index 49aacb0a327c..a9bc546626ab 100644
--- a/drivers/usb/serial/kobil_sct.c
+++ b/drivers/usb/serial/kobil_sct.c
@@ -48,7 +48,7 @@
 
 /* Function prototypes */
 static int kobil_port_probe(struct usb_serial_port *probe);
-static int kobil_port_remove(struct usb_serial_port *probe);
+static void kobil_port_remove(struct usb_serial_port *probe);
 static int  kobil_open(struct tty_struct *tty, struct usb_serial_port *port);
 static void kobil_close(struct usb_serial_port *port);
 static int  kobil_write(struct tty_struct *tty, struct usb_serial_port *port,
@@ -143,14 +143,12 @@ static int kobil_port_probe(struct usb_serial_port *port)
 }
 
 
-static int kobil_port_remove(struct usb_serial_port *port)
+static void kobil_port_remove(struct usb_serial_port *port)
 {
 	struct kobil_private *priv;
 
 	priv = usb_get_serial_port_data(port);
 	kfree(priv);
-
-	return 0;
 }
 
 static void kobil_init_termios(struct tty_struct *tty)
diff --git a/drivers/usb/serial/mct_u232.c b/drivers/usb/serial/mct_u232.c
index 7887c312d9a9..ecd5b921e374 100644
--- a/drivers/usb/serial/mct_u232.c
+++ b/drivers/usb/serial/mct_u232.c
@@ -39,7 +39,7 @@
  * Function prototypes
  */
 static int  mct_u232_port_probe(struct usb_serial_port *port);
-static int  mct_u232_port_remove(struct usb_serial_port *remove);
+static void mct_u232_port_remove(struct usb_serial_port *remove);
 static int  mct_u232_open(struct tty_struct *tty, struct usb_serial_port *port);
 static void mct_u232_close(struct usb_serial_port *port);
 static void mct_u232_dtr_rts(struct usb_serial_port *port, int on);
@@ -400,14 +400,12 @@ static int mct_u232_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int mct_u232_port_remove(struct usb_serial_port *port)
+static void mct_u232_port_remove(struct usb_serial_port *port)
 {
 	struct mct_u232_private *priv;
 
 	priv = usb_get_serial_port_data(port);
 	kfree(priv);
-
-	return 0;
 }
 
 static int  mct_u232_open(struct tty_struct *tty, struct usb_serial_port *port)
diff --git a/drivers/usb/serial/metro-usb.c b/drivers/usb/serial/metro-usb.c
index e63cea02cfd8..0bfe4459c37f 100644
--- a/drivers/usb/serial/metro-usb.c
+++ b/drivers/usb/serial/metro-usb.c
@@ -256,14 +256,12 @@ static int metrousb_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int metrousb_port_remove(struct usb_serial_port *port)
+static void metrousb_port_remove(struct usb_serial_port *port)
 {
 	struct metrousb_private *metro_priv;
 
 	metro_priv = usb_get_serial_port_data(port);
 	kfree(metro_priv);
-
-	return 0;
 }
 
 static void metrousb_throttle(struct tty_struct *tty)
diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index aa55169796a3..701dfb32b129 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -1760,14 +1760,12 @@ static int mos7720_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int mos7720_port_remove(struct usb_serial_port *port)
+static void mos7720_port_remove(struct usb_serial_port *port)
 {
 	struct moschip_port *mos7720_port;
 
 	mos7720_port = usb_get_serial_port_data(port);
 	kfree(mos7720_port);
-
-	return 0;
 }
 
 static struct usb_serial_driver moschip7720_2port_driver = {
diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 30c25ef0dacd..1bf0d066f55a 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -1745,7 +1745,7 @@ error:
 	return status;
 }
 
-static int mos7840_port_remove(struct usb_serial_port *port)
+static void mos7840_port_remove(struct usb_serial_port *port)
 {
 	struct moschip_port *mos7840_port = usb_get_serial_port_data(port);
 
@@ -1762,8 +1762,6 @@ static int mos7840_port_remove(struct usb_serial_port *port)
 	}
 
 	kfree(mos7840_port);
-
-	return 0;
 }
 
 static struct usb_serial_driver moschip7840_4port_device = {
diff --git a/drivers/usb/serial/omninet.c b/drivers/usb/serial/omninet.c
index 5b6e982a9376..83c62f920c50 100644
--- a/drivers/usb/serial/omninet.c
+++ b/drivers/usb/serial/omninet.c
@@ -36,7 +36,7 @@ static int omninet_prepare_write_buffer(struct usb_serial_port *port,
 static int omninet_calc_num_ports(struct usb_serial *serial,
 				struct usb_serial_endpoints *epds);
 static int omninet_port_probe(struct usb_serial_port *port);
-static int omninet_port_remove(struct usb_serial_port *port);
+static void omninet_port_remove(struct usb_serial_port *port);
 
 static const struct usb_device_id id_table[] = {
 	{ USB_DEVICE(ZYXEL_VENDOR_ID, ZYXEL_OMNINET_ID) },
@@ -121,14 +121,12 @@ static int omninet_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int omninet_port_remove(struct usb_serial_port *port)
+static void omninet_port_remove(struct usb_serial_port *port)
 {
 	struct omninet_data *od;
 
 	od = usb_get_serial_port_data(port);
 	kfree(od);
-
-	return 0;
 }
 
 #define OMNINET_HEADERLEN	4
diff --git a/drivers/usb/serial/opticon.c b/drivers/usb/serial/opticon.c
index 0af76800bd78..eecb72aef83e 100644
--- a/drivers/usb/serial/opticon.c
+++ b/drivers/usb/serial/opticon.c
@@ -385,13 +385,11 @@ static int opticon_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int opticon_port_remove(struct usb_serial_port *port)
+static void opticon_port_remove(struct usb_serial_port *port)
 {
 	struct opticon_private *priv = usb_get_serial_port_data(port);
 
 	kfree(priv);
-
-	return 0;
 }
 
 static struct usb_serial_driver opticon_device = {
diff --git a/drivers/usb/serial/oti6858.c b/drivers/usb/serial/oti6858.c
index 8151dd7a45e8..65cd0341fa78 100644
--- a/drivers/usb/serial/oti6858.c
+++ b/drivers/usb/serial/oti6858.c
@@ -132,7 +132,7 @@ static int oti6858_tiocmget(struct tty_struct *tty);
 static int oti6858_tiocmset(struct tty_struct *tty,
 				unsigned int set, unsigned int clear);
 static int oti6858_port_probe(struct usb_serial_port *port);
-static int oti6858_port_remove(struct usb_serial_port *port);
+static void oti6858_port_remove(struct usb_serial_port *port);
 
 /* device info */
 static struct usb_serial_driver oti6858_device = {
@@ -344,14 +344,12 @@ static int oti6858_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int oti6858_port_remove(struct usb_serial_port *port)
+static void oti6858_port_remove(struct usb_serial_port *port)
 {
 	struct oti6858_private *priv;
 
 	priv = usb_get_serial_port_data(port);
 	kfree(priv);
-
-	return 0;
 }
 
 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index 29dda60e3bcd..eed9acd1ae08 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -450,13 +450,11 @@ static int pl2303_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int pl2303_port_remove(struct usb_serial_port *port)
+static void pl2303_port_remove(struct usb_serial_port *port)
 {
 	struct pl2303_private *priv = usb_get_serial_port_data(port);
 
 	kfree(priv);
-
-	return 0;
 }
 
 static int pl2303_set_control_lines(struct usb_serial_port *port, u8 value)
diff --git a/drivers/usb/serial/quatech2.c b/drivers/usb/serial/quatech2.c
index 872d1bc86ab4..599dcb2e374d 100644
--- a/drivers/usb/serial/quatech2.c
+++ b/drivers/usb/serial/quatech2.c
@@ -727,7 +727,7 @@ err_buf:
 	return -ENOMEM;
 }
 
-static int qt2_port_remove(struct usb_serial_port *port)
+static void qt2_port_remove(struct usb_serial_port *port)
 {
 	struct qt2_port_private *port_priv;
 
@@ -735,8 +735,6 @@ static int qt2_port_remove(struct usb_serial_port *port)
 	usb_free_urb(port_priv->write_urb);
 	kfree(port_priv->write_buffer);
 	kfree(port_priv);
-
-	return 0;
 }
 
 static int qt2_tiocmget(struct tty_struct *tty)
diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index 57fc3c31712e..54e16ffc30a0 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -901,15 +901,13 @@ static int sierra_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int sierra_port_remove(struct usb_serial_port *port)
+static void sierra_port_remove(struct usb_serial_port *port)
 {
 	struct sierra_port_private *portdata;
 
 	portdata = usb_get_serial_port_data(port);
 	usb_set_serial_port_data(port, NULL);
 	kfree(portdata);
-
-	return 0;
 }
 
 #ifdef CONFIG_PM
diff --git a/drivers/usb/serial/spcp8x5.c b/drivers/usb/serial/spcp8x5.c
index 3bac55bd9bd9..7039dc918827 100644
--- a/drivers/usb/serial/spcp8x5.c
+++ b/drivers/usb/serial/spcp8x5.c
@@ -169,14 +169,12 @@ static int spcp8x5_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int spcp8x5_port_remove(struct usb_serial_port *port)
+static void spcp8x5_port_remove(struct usb_serial_port *port)
 {
 	struct spcp8x5_private *priv;
 
 	priv = usb_get_serial_port_data(port);
 	kfree(priv);
-
-	return 0;
 }
 
 static int spcp8x5_set_ctrl_line(struct usb_serial_port *port, u8 mcr)
diff --git a/drivers/usb/serial/ssu100.c b/drivers/usb/serial/ssu100.c
index 7d39d35e52a1..89fdc5c19285 100644
--- a/drivers/usb/serial/ssu100.c
+++ b/drivers/usb/serial/ssu100.c
@@ -366,14 +366,12 @@ static int ssu100_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int ssu100_port_remove(struct usb_serial_port *port)
+static void ssu100_port_remove(struct usb_serial_port *port)
 {
 	struct ssu100_port_private *priv;
 
 	priv = usb_get_serial_port_data(port);
 	kfree(priv);
-
-	return 0;
 }
 
 static int ssu100_tiocmget(struct tty_struct *tty)
diff --git a/drivers/usb/serial/symbolserial.c b/drivers/usb/serial/symbolserial.c
index 6ca24e86f686..d7f73ad6e778 100644
--- a/drivers/usb/serial/symbolserial.c
+++ b/drivers/usb/serial/symbolserial.c
@@ -160,13 +160,11 @@ static int symbol_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int symbol_port_remove(struct usb_serial_port *port)
+static void symbol_port_remove(struct usb_serial_port *port)
 {
 	struct symbol_private *priv = usb_get_serial_port_data(port);
 
 	kfree(priv);
-
-	return 0;
 }
 
 static struct usb_serial_driver symbol_device = {
diff --git a/drivers/usb/serial/ti_usb_3410_5052.c b/drivers/usb/serial/ti_usb_3410_5052.c
index 73075b9351c5..7252b0ce75a6 100644
--- a/drivers/usb/serial/ti_usb_3410_5052.c
+++ b/drivers/usb/serial/ti_usb_3410_5052.c
@@ -303,7 +303,7 @@ struct ti_device {
 static int ti_startup(struct usb_serial *serial);
 static void ti_release(struct usb_serial *serial);
 static int ti_port_probe(struct usb_serial_port *port);
-static int ti_port_remove(struct usb_serial_port *port);
+static void ti_port_remove(struct usb_serial_port *port);
 static int ti_open(struct tty_struct *tty, struct usb_serial_port *port);
 static void ti_close(struct usb_serial_port *port);
 static int ti_write(struct tty_struct *tty, struct usb_serial_port *port,
@@ -629,14 +629,12 @@ static int ti_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int ti_port_remove(struct usb_serial_port *port)
+static void ti_port_remove(struct usb_serial_port *port)
 {
 	struct ti_port *tport;
 
 	tport = usb_get_serial_port_data(port);
 	kfree(tport);
-
-	return 0;
 }
 
 static int ti_open(struct tty_struct *tty, struct usb_serial_port *port)
diff --git a/drivers/usb/serial/upd78f0730.c b/drivers/usb/serial/upd78f0730.c
index 1ca9c1881621..26d7b003b7e3 100644
--- a/drivers/usb/serial/upd78f0730.c
+++ b/drivers/usb/serial/upd78f0730.c
@@ -171,15 +171,13 @@ static int upd78f0730_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int upd78f0730_port_remove(struct usb_serial_port *port)
+static void upd78f0730_port_remove(struct usb_serial_port *port)
 {
 	struct upd78f0730_port_private *private;
 
 	private = usb_get_serial_port_data(port);
 	mutex_destroy(&private->lock);
 	kfree(private);
-
-	return 0;
 }
 
 static int upd78f0730_tiocmget(struct tty_struct *tty)
diff --git a/drivers/usb/serial/usb-wwan.h b/drivers/usb/serial/usb-wwan.h
index 934e9361cf6b..79dafd98e0a1 100644
--- a/drivers/usb/serial/usb-wwan.h
+++ b/drivers/usb/serial/usb-wwan.h
@@ -10,7 +10,7 @@ extern void usb_wwan_dtr_rts(struct usb_serial_port *port, int on);
 extern int usb_wwan_open(struct tty_struct *tty, struct usb_serial_port *port);
 extern void usb_wwan_close(struct usb_serial_port *port);
 extern int usb_wwan_port_probe(struct usb_serial_port *port);
-extern int usb_wwan_port_remove(struct usb_serial_port *port);
+extern void usb_wwan_port_remove(struct usb_serial_port *port);
 extern int usb_wwan_write_room(struct tty_struct *tty);
 extern int usb_wwan_tiocmget(struct tty_struct *tty);
 extern int usb_wwan_tiocmset(struct tty_struct *tty,
diff --git a/drivers/usb/serial/usb_wwan.c b/drivers/usb/serial/usb_wwan.c
index 4b9845807bee..46d46a4f99c9 100644
--- a/drivers/usb/serial/usb_wwan.c
+++ b/drivers/usb/serial/usb_wwan.c
@@ -544,7 +544,7 @@ bail_out_error:
 }
 EXPORT_SYMBOL_GPL(usb_wwan_port_probe);
 
-int usb_wwan_port_remove(struct usb_serial_port *port)
+void usb_wwan_port_remove(struct usb_serial_port *port)
 {
 	int i;
 	struct usb_wwan_port_private *portdata;
@@ -562,8 +562,6 @@ int usb_wwan_port_remove(struct usb_serial_port *port)
 	}
 
 	kfree(portdata);
-
-	return 0;
 }
 EXPORT_SYMBOL(usb_wwan_port_remove);
 
diff --git a/drivers/usb/serial/whiteheat.c b/drivers/usb/serial/whiteheat.c
index ca3bd58f2025..ccfd5ed652cd 100644
--- a/drivers/usb/serial/whiteheat.c
+++ b/drivers/usb/serial/whiteheat.c
@@ -79,7 +79,7 @@ static int  whiteheat_firmware_attach(struct usb_serial *serial);
 static int  whiteheat_attach(struct usb_serial *serial);
 static void whiteheat_release(struct usb_serial *serial);
 static int  whiteheat_port_probe(struct usb_serial_port *port);
-static int  whiteheat_port_remove(struct usb_serial_port *port);
+static void whiteheat_port_remove(struct usb_serial_port *port);
 static int  whiteheat_open(struct tty_struct *tty,
 			struct usb_serial_port *port);
 static void whiteheat_close(struct usb_serial_port *port);
@@ -345,14 +345,12 @@ static int whiteheat_port_probe(struct usb_serial_port *port)
 	return 0;
 }
 
-static int whiteheat_port_remove(struct usb_serial_port *port)
+static void whiteheat_port_remove(struct usb_serial_port *port)
 {
 	struct whiteheat_private *info;
 
 	info = usb_get_serial_port_data(port);
 	kfree(info);
-
-	return 0;
 }
 
 static int whiteheat_open(struct tty_struct *tty, struct usb_serial_port *port)
diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index 1c09b922f8b0..952272002e48 100644
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -260,7 +260,7 @@ struct usb_serial_driver {
 	void (*release)(struct usb_serial *serial);
 
 	int (*port_probe)(struct usb_serial_port *port);
-	int (*port_remove)(struct usb_serial_port *port);
+	void (*port_remove)(struct usb_serial_port *port);
 
 	int (*suspend)(struct usb_serial *serial, pm_message_t message);
 	int (*resume)(struct usb_serial *serial);

From 1542d1324be1191d970f69c55e885af5dd810b84 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@kernel.org>
Date: Mon, 8 Feb 2021 16:48:06 +0100
Subject: [PATCH 41/41] USB: serial: drop bogus to_usb_serial_port() checks
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The to_usb_serial_port() macro is implemented using container_of() so
there's no need to check for NULL.

Note that neither bus match() or probe() is ever called with a NULL
struct device pointer so the checks weren't just misplaced.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/bus.c | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/drivers/usb/serial/bus.c b/drivers/usb/serial/bus.c
index 1a8c7821d00a..7133818a58b9 100644
--- a/drivers/usb/serial/bus.c
+++ b/drivers/usb/serial/bus.c
@@ -16,19 +16,13 @@
 static int usb_serial_device_match(struct device *dev,
 						struct device_driver *drv)
 {
-	struct usb_serial_driver *driver;
-	const struct usb_serial_port *port;
+	const struct usb_serial_port *port = to_usb_serial_port(dev);
+	struct usb_serial_driver *driver = to_usb_serial_driver(drv);
 
 	/*
 	 * drivers are already assigned to ports in serial_probe so it's
 	 * a simple check here.
 	 */
-	port = to_usb_serial_port(dev);
-	if (!port)
-		return 0;
-
-	driver = to_usb_serial_driver(drv);
-
 	if (driver == port->serial->type)
 		return 1;
 
@@ -37,16 +31,12 @@ static int usb_serial_device_match(struct device *dev,
 
 static int usb_serial_device_probe(struct device *dev)
 {
+	struct usb_serial_port *port = to_usb_serial_port(dev);
 	struct usb_serial_driver *driver;
-	struct usb_serial_port *port;
 	struct device *tty_dev;
 	int retval = 0;
 	int minor;
 
-	port = to_usb_serial_port(dev);
-	if (!port)
-		return -ENODEV;
-
 	/* make sure suspend/resume doesn't race against port_probe */
 	retval = usb_autopm_get_interface(port->serial->interface);
 	if (retval)