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linux/drivers/usb/misc/usb3503.c
Julius Werner 06a962fa7f usb: misc: usb3503: Remove 100ms sleep on reset, conform to data sheet 
The usb3503 driver sleeps a flat 100ms when resetting the chip, with a
comment about waiting for the reference clock. This seems to be a
board-specific detail that should not hold up boot across all platforms.
This patch reduces the sleep to the 4ms initialization delay that the
chip itself actually requires (as per its data sheet). If certain boards
require more time to set up the reference clock, they should change this
through local patches or add a proper, configurable synchronization
mechanism.

Signed-off-by: Julius Werner <jwerner@chromium.org>
Signed-off-by: Dongjin Kim <tobetter@gmail.com>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-06-03 11:01:09 -07:00

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/*
* Driver for SMSC USB3503 USB 2.0 hub controller driver
*
* Copyright (c) 2012-2013 Dongjin Kim (tobetter@gmail.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/i2c.h>
#include <linux/gpio.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/of_gpio.h>
#include <linux/platform_device.h>
#include <linux/platform_data/usb3503.h>
#define USB3503_VIDL 0x00
#define USB3503_VIDM 0x01
#define USB3503_PIDL 0x02
#define USB3503_PIDM 0x03
#define USB3503_DIDL 0x04
#define USB3503_DIDM 0x05
#define USB3503_CFG1 0x06
#define USB3503_SELF_BUS_PWR (1 << 7)
#define USB3503_CFG2 0x07
#define USB3503_CFG3 0x08
#define USB3503_NRD 0x09
#define USB3503_PDS 0x0a
#define USB3503_SP_ILOCK 0xe7
#define USB3503_SPILOCK_CONNECT (1 << 1)
#define USB3503_SPILOCK_CONFIG (1 << 0)
#define USB3503_CFGP 0xee
#define USB3503_CLKSUSP (1 << 7)
struct usb3503 {
enum usb3503_mode mode;
struct i2c_client *client;
u8 port_off_mask;
int gpio_intn;
int gpio_reset;
int gpio_connect;
};
static int usb3503_write_register(struct i2c_client *client,
char reg, char data)
{
return i2c_smbus_write_byte_data(client, reg, data);
}
static int usb3503_read_register(struct i2c_client *client, char reg)
{
return i2c_smbus_read_byte_data(client, reg);
}
static int usb3503_set_bits(struct i2c_client *client, char reg, char req)
{
int err;
err = usb3503_read_register(client, reg);
if (err < 0)
return err;
err = usb3503_write_register(client, reg, err | req);
if (err < 0)
return err;
return 0;
}
static int usb3503_clear_bits(struct i2c_client *client, char reg, char req)
{
int err;
err = usb3503_read_register(client, reg);
if (err < 0)
return err;
err = usb3503_write_register(client, reg, err & ~req);
if (err < 0)
return err;
return 0;
}
static int usb3503_reset(int gpio_reset, int state)
{
if (gpio_is_valid(gpio_reset))
gpio_set_value(gpio_reset, state);
/* Wait T_HUBINIT == 4ms for hub logic to stabilize */
if (state)
usleep_range(4000, 10000);
return 0;
}
static int usb3503_switch_mode(struct usb3503 *hub, enum usb3503_mode mode)
{
struct i2c_client *i2c = hub->client;
int err = 0;
switch (mode) {
case USB3503_MODE_HUB:
usb3503_reset(hub->gpio_reset, 1);
/* SP_ILOCK: set connect_n, config_n for config */
err = usb3503_write_register(i2c, USB3503_SP_ILOCK,
(USB3503_SPILOCK_CONNECT
| USB3503_SPILOCK_CONFIG));
if (err < 0) {
dev_err(&i2c->dev, "SP_ILOCK failed (%d)\n", err);
goto err_hubmode;
}
/* PDS : Disable For Self Powered Operation */
if (hub->port_off_mask) {
err = usb3503_set_bits(i2c, USB3503_PDS,
hub->port_off_mask);
if (err < 0) {
dev_err(&i2c->dev, "PDS failed (%d)\n", err);
goto err_hubmode;
}
}
/* CFG1 : SELF_BUS_PWR -> Self-Powerd operation */
err = usb3503_set_bits(i2c, USB3503_CFG1, USB3503_SELF_BUS_PWR);
if (err < 0) {
dev_err(&i2c->dev, "CFG1 failed (%d)\n", err);
goto err_hubmode;
}
/* SP_LOCK: clear connect_n, config_n for hub connect */
err = usb3503_clear_bits(i2c, USB3503_SP_ILOCK,
(USB3503_SPILOCK_CONNECT
| USB3503_SPILOCK_CONFIG));
if (err < 0) {
dev_err(&i2c->dev, "SP_ILOCK failed (%d)\n", err);
goto err_hubmode;
}
hub->mode = mode;
dev_info(&i2c->dev, "switched to HUB mode\n");
break;
case USB3503_MODE_STANDBY:
usb3503_reset(hub->gpio_reset, 0);
hub->mode = mode;
dev_info(&i2c->dev, "switched to STANDBY mode\n");
break;
default:
dev_err(&i2c->dev, "unknown mode is request\n");
err = -EINVAL;
break;
}
err_hubmode:
return err;
}
static int usb3503_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
{
struct usb3503_platform_data *pdata = i2c->dev.platform_data;
struct device_node *np = i2c->dev.of_node;
struct usb3503 *hub;
int err = -ENOMEM;
u32 mode = USB3503_MODE_UNKNOWN;
const u32 *property;
int len;
hub = kzalloc(sizeof(struct usb3503), GFP_KERNEL);
if (!hub) {
dev_err(&i2c->dev, "private data alloc fail\n");
return err;
}
i2c_set_clientdata(i2c, hub);
hub->client = i2c;
if (pdata) {
hub->port_off_mask = pdata->port_off_mask;
hub->gpio_intn = pdata->gpio_intn;
hub->gpio_connect = pdata->gpio_connect;
hub->gpio_reset = pdata->gpio_reset;
hub->mode = pdata->initial_mode;
} else if (np) {
hub->port_off_mask = 0;
property = of_get_property(np, "disabled-ports", &len);
if (property && (len / sizeof(u32)) > 0) {
int i;
for (i = 0; i < len / sizeof(u32); i++) {
u32 port = be32_to_cpu(property[i]);
if ((1 <= port) && (port <= 3))
hub->port_off_mask |= (1 << port);
}
}
hub->gpio_intn = of_get_named_gpio(np, "connect-gpios", 0);
if (hub->gpio_intn == -EPROBE_DEFER)
return -EPROBE_DEFER;
hub->gpio_connect = of_get_named_gpio(np, "intn-gpios", 0);
if (hub->gpio_connect == -EPROBE_DEFER)
return -EPROBE_DEFER;
hub->gpio_reset = of_get_named_gpio(np, "reset-gpios", 0);
if (hub->gpio_reset == -EPROBE_DEFER)
return -EPROBE_DEFER;
of_property_read_u32(np, "initial-mode", &mode);
hub->mode = mode;
}
if (gpio_is_valid(hub->gpio_intn)) {
err = gpio_request_one(hub->gpio_intn,
GPIOF_OUT_INIT_HIGH, "usb3503 intn");
if (err) {
dev_err(&i2c->dev,
"unable to request GPIO %d as connect pin (%d)\n",
hub->gpio_intn, err);
goto err_out;
}
}
if (gpio_is_valid(hub->gpio_connect)) {
err = gpio_request_one(hub->gpio_connect,
GPIOF_OUT_INIT_HIGH, "usb3503 connect");
if (err) {
dev_err(&i2c->dev,
"unable to request GPIO %d as connect pin (%d)\n",
hub->gpio_connect, err);
goto err_gpio_connect;
}
}
if (gpio_is_valid(hub->gpio_reset)) {
err = gpio_request_one(hub->gpio_reset,
GPIOF_OUT_INIT_LOW, "usb3503 reset");
if (err) {
dev_err(&i2c->dev,
"unable to request GPIO %d as reset pin (%d)\n",
hub->gpio_reset, err);
goto err_gpio_reset;
}
}
usb3503_switch_mode(hub, hub->mode);
dev_info(&i2c->dev, "%s: probed on %s mode\n", __func__,
(hub->mode == USB3503_MODE_HUB) ? "hub" : "standby");
return 0;
err_gpio_reset:
if (gpio_is_valid(hub->gpio_connect))
gpio_free(hub->gpio_connect);
err_gpio_connect:
if (gpio_is_valid(hub->gpio_intn))
gpio_free(hub->gpio_intn);
err_out:
kfree(hub);
return err;
}
static int usb3503_remove(struct i2c_client *i2c)
{
struct usb3503 *hub = i2c_get_clientdata(i2c);
if (gpio_is_valid(hub->gpio_intn))
gpio_free(hub->gpio_intn);
if (gpio_is_valid(hub->gpio_connect))
gpio_free(hub->gpio_connect);
if (gpio_is_valid(hub->gpio_reset))
gpio_free(hub->gpio_reset);
kfree(hub);
return 0;
}
static const struct i2c_device_id usb3503_id[] = {
{ USB3503_I2C_NAME, 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, usb3503_id);
#ifdef CONFIG_OF
static const struct of_device_id usb3503_of_match[] = {
{ .compatible = "smsc,usb3503", },
{},
};
MODULE_DEVICE_TABLE(of, usb3503_of_match);
#endif
static struct i2c_driver usb3503_driver = {
.driver = {
.name = USB3503_I2C_NAME,
.of_match_table = of_match_ptr(usb3503_of_match),
},
.probe = usb3503_probe,
.remove = usb3503_remove,
.id_table = usb3503_id,
};
module_i2c_driver(usb3503_driver);
MODULE_AUTHOR("Dongjin Kim <tobetter@gmail.com>");
MODULE_DESCRIPTION("USB3503 USB HUB driver");
MODULE_LICENSE("GPL");
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