linux/drivers/media/usb/em28xx/em28xx-i2c.c
Frank Schaefer 90271964c9 [media] em28xx: consider the message length limitation of the i2c adapter when reading the eeprom
EEPROMs are currently read in blocks of 16 bytes, but the em2800 is limited
to 4 bytes per read. All other chip variants support reading of max. 64 bytes
at once (according to the em258x datasheet; also verified with em2710, em2882,
and em28174).
Since em2800_i2c_recv_bytes() has been fixed to return with -EOPNOTSUPP when
more than 4 bytes are requested, EEPROM reading with this chip is broken.
It was actually broken before that change, too, it just didn't throw an error
because the i2c adapter silently returned trash data (for all reads >1 byte !).

Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2013-01-05 01:19:11 -02:00

629 lines
15 KiB
C

/*
em28xx-i2c.c - driver for Empia EM2800/EM2820/2840 USB video capture devices
Copyright (C) 2005 Ludovico Cavedon <cavedon@sssup.it>
Markus Rechberger <mrechberger@gmail.com>
Mauro Carvalho Chehab <mchehab@infradead.org>
Sascha Sommer <saschasommer@freenet.de>
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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/usb.h>
#include <linux/i2c.h>
#include "em28xx.h"
#include "tuner-xc2028.h"
#include <media/v4l2-common.h>
#include <media/tuner.h>
/* ----------------------------------------------------------- */
static unsigned int i2c_scan;
module_param(i2c_scan, int, 0444);
MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
static unsigned int i2c_debug;
module_param(i2c_debug, int, 0644);
MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
#define dprintk2(lvl, fmt, args...) \
do { \
if (i2c_debug >= lvl) { \
printk(KERN_DEBUG "%s at %s: " fmt, \
dev->name, __func__ , ##args); \
} \
} while (0)
/*
* em2800_i2c_send_bytes()
* send up to 4 bytes to the em2800 i2c device
*/
static int em2800_i2c_send_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len)
{
int ret;
int write_timeout;
u8 b2[6];
if (len < 1 || len > 4)
return -EOPNOTSUPP;
BUG_ON(len < 1 || len > 4);
b2[5] = 0x80 + len - 1;
b2[4] = addr;
b2[3] = buf[0];
if (len > 1)
b2[2] = buf[1];
if (len > 2)
b2[1] = buf[2];
if (len > 3)
b2[0] = buf[3];
/* trigger write */
ret = dev->em28xx_write_regs(dev, 4 - len, &b2[4 - len], 2 + len);
if (ret != 2 + len) {
em28xx_warn("failed to trigger write to i2c address 0x%x "
"(error=%i)\n", addr, ret);
return (ret < 0) ? ret : -EIO;
}
/* wait for completion */
for (write_timeout = EM2800_I2C_XFER_TIMEOUT; write_timeout > 0;
write_timeout -= 5) {
ret = dev->em28xx_read_reg(dev, 0x05);
if (ret == 0x80 + len - 1) {
return len;
} else if (ret == 0x94 + len - 1) {
return -ENODEV;
} else if (ret < 0) {
em28xx_warn("failed to get i2c transfer status from "
"bridge register (error=%i)\n", ret);
return ret;
}
msleep(5);
}
em28xx_warn("write to i2c device at 0x%x timed out\n", addr);
return -EIO;
}
/*
* em2800_i2c_recv_bytes()
* read up to 4 bytes from the em2800 i2c device
*/
static int em2800_i2c_recv_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len)
{
u8 buf2[4];
int ret;
int read_timeout;
int i;
if (len < 1 || len > 4)
return -EOPNOTSUPP;
/* trigger read */
buf2[1] = 0x84 + len - 1;
buf2[0] = addr;
ret = dev->em28xx_write_regs(dev, 0x04, buf2, 2);
if (ret != 2) {
em28xx_warn("failed to trigger read from i2c address 0x%x "
"(error=%i)\n", addr, ret);
return (ret < 0) ? ret : -EIO;
}
/* wait for completion */
for (read_timeout = EM2800_I2C_XFER_TIMEOUT; read_timeout > 0;
read_timeout -= 5) {
ret = dev->em28xx_read_reg(dev, 0x05);
if (ret == 0x84 + len - 1) {
break;
} else if (ret == 0x94 + len - 1) {
return -ENODEV;
} else if (ret < 0) {
em28xx_warn("failed to get i2c transfer status from "
"bridge register (error=%i)\n", ret);
return ret;
}
msleep(5);
}
if (ret != 0x84 + len - 1)
em28xx_warn("read from i2c device at 0x%x timed out\n", addr);
/* get the received message */
ret = dev->em28xx_read_reg_req_len(dev, 0x00, 4-len, buf2, len);
if (ret != len) {
em28xx_warn("reading from i2c device at 0x%x failed: "
"couldn't get the received message from the bridge "
"(error=%i)\n", addr, ret);
return (ret < 0) ? ret : -EIO;
}
for (i = 0; i < len; i++)
buf[i] = buf2[len - 1 - i];
return ret;
}
/*
* em2800_i2c_check_for_device()
* check if there is an i2c device at the supplied address
*/
static int em2800_i2c_check_for_device(struct em28xx *dev, u8 addr)
{
u8 buf;
int ret;
ret = em2800_i2c_recv_bytes(dev, addr, &buf, 1);
if (ret == 1)
return 0;
return (ret < 0) ? ret : -EIO;
}
/*
* em28xx_i2c_send_bytes()
*/
static int em28xx_i2c_send_bytes(struct em28xx *dev, u16 addr, u8 *buf,
u16 len, int stop)
{
int write_timeout, ret;
if (len < 1 || len > 64)
return -EOPNOTSUPP;
/* NOTE: limited by the USB ctrl message constraints
* Zero length reads always succeed, even if no device is connected */
/* Write to i2c device */
ret = dev->em28xx_write_regs_req(dev, stop ? 2 : 3, addr, buf, len);
if (ret != len) {
if (ret < 0) {
em28xx_warn("writing to i2c device at 0x%x failed "
"(error=%i)\n", addr, ret);
return ret;
} else {
em28xx_warn("%i bytes write to i2c device at 0x%x "
"requested, but %i bytes written\n",
len, addr, ret);
return -EIO;
}
}
/* Check success of the i2c operation */
for (write_timeout = EM2800_I2C_XFER_TIMEOUT; write_timeout > 0;
write_timeout -= 5) {
ret = dev->em28xx_read_reg(dev, 0x05);
if (ret == 0) { /* success */
return len;
} else if (ret == 0x10) {
return -ENODEV;
} else if (ret < 0) {
em28xx_warn("failed to read i2c transfer status from "
"bridge (error=%i)\n", ret);
return ret;
}
msleep(5);
/* NOTE: do we really have to wait for success ?
Never seen anything else than 0x00 or 0x10
(even with high payload) ... */
}
em28xx_warn("write to i2c device at 0x%x timed out\n", addr);
return -EIO;
}
/*
* em28xx_i2c_recv_bytes()
* read a byte from the i2c device
*/
static int em28xx_i2c_recv_bytes(struct em28xx *dev, u16 addr, u8 *buf, u16 len)
{
int ret;
if (len < 1 || len > 64)
return -EOPNOTSUPP;
/* NOTE: limited by the USB ctrl message constraints
* Zero length reads always succeed, even if no device is connected */
/* Read data from i2c device */
ret = dev->em28xx_read_reg_req_len(dev, 2, addr, buf, len);
if (ret != len) {
if (ret < 0) {
em28xx_warn("reading from i2c device at 0x%x failed "
"(error=%i)\n", addr, ret);
return ret;
} else {
em28xx_warn("%i bytes requested from i2c device at "
"0x%x, but %i bytes received\n",
len, addr, ret);
return -EIO;
}
}
/* Check success of the i2c operation */
ret = dev->em28xx_read_reg(dev, 0x05);
if (ret < 0) {
em28xx_warn("failed to read i2c transfer status from "
"bridge (error=%i)\n", ret);
return ret;
}
if (ret > 0) {
if (ret == 0x10) {
return -ENODEV;
} else {
em28xx_warn("unknown i2c error (status=%i)\n", ret);
return -EIO;
}
}
return len;
}
/*
* em28xx_i2c_check_for_device()
* check if there is a i2c_device at the supplied address
*/
static int em28xx_i2c_check_for_device(struct em28xx *dev, u16 addr)
{
int ret;
u8 buf;
ret = em28xx_i2c_recv_bytes(dev, addr, &buf, 1);
if (ret == 1)
return 0;
return (ret < 0) ? ret : -EIO;
}
/*
* em28xx_i2c_xfer()
* the main i2c transfer function
*/
static int em28xx_i2c_xfer(struct i2c_adapter *i2c_adap,
struct i2c_msg msgs[], int num)
{
struct em28xx *dev = i2c_adap->algo_data;
int addr, rc, i, byte;
if (num <= 0)
return 0;
for (i = 0; i < num; i++) {
addr = msgs[i].addr << 1;
dprintk2(2, "%s %s addr=%x len=%d:",
(msgs[i].flags & I2C_M_RD) ? "read" : "write",
i == num - 1 ? "stop" : "nonstop", addr, msgs[i].len);
if (!msgs[i].len) { /* no len: check only for device presence */
if (dev->board.is_em2800)
rc = em2800_i2c_check_for_device(dev, addr);
else
rc = em28xx_i2c_check_for_device(dev, addr);
if (rc == -ENODEV) {
if (i2c_debug >= 2)
printk(" no device\n");
return rc;
}
} else if (msgs[i].flags & I2C_M_RD) {
/* read bytes */
if (dev->board.is_em2800)
rc = em2800_i2c_recv_bytes(dev, addr,
msgs[i].buf,
msgs[i].len);
else
rc = em28xx_i2c_recv_bytes(dev, addr,
msgs[i].buf,
msgs[i].len);
if (i2c_debug >= 2) {
for (byte = 0; byte < msgs[i].len; byte++)
printk(" %02x", msgs[i].buf[byte]);
}
} else {
/* write bytes */
if (i2c_debug >= 2) {
for (byte = 0; byte < msgs[i].len; byte++)
printk(" %02x", msgs[i].buf[byte]);
}
if (dev->board.is_em2800)
rc = em2800_i2c_send_bytes(dev, addr,
msgs[i].buf,
msgs[i].len);
else
rc = em28xx_i2c_send_bytes(dev, addr,
msgs[i].buf,
msgs[i].len,
i == num - 1);
}
if (rc < 0) {
if (i2c_debug >= 2)
printk(" ERROR: %i\n", rc);
return rc;
}
if (i2c_debug >= 2)
printk("\n");
}
return num;
}
/* based on linux/sunrpc/svcauth.h and linux/hash.h
* The original hash function returns a different value, if arch is x86_64
* or i386.
*/
static inline unsigned long em28xx_hash_mem(char *buf, int length, int bits)
{
unsigned long hash = 0;
unsigned long l = 0;
int len = 0;
unsigned char c;
do {
if (len == length) {
c = (char)len;
len = -1;
} else
c = *buf++;
l = (l << 8) | c;
len++;
if ((len & (32 / 8 - 1)) == 0)
hash = ((hash^l) * 0x9e370001UL);
} while (len);
return (hash >> (32 - bits)) & 0xffffffffUL;
}
static int em28xx_i2c_eeprom(struct em28xx *dev, unsigned char *eedata, int len)
{
unsigned char buf, *p = eedata;
struct em28xx_eeprom *em_eeprom = (void *)eedata;
int i, err, size = len, block, block_max;
if (dev->chip_id == CHIP_ID_EM2874 ||
dev->chip_id == CHIP_ID_EM28174 ||
dev->chip_id == CHIP_ID_EM2884) {
/* Empia switched to a 16-bit addressable eeprom in newer
devices. While we could certainly write a routine to read
the eeprom, there is nothing of use in there that cannot be
accessed through registers, and there is the risk that we
could corrupt the eeprom (since a 16-bit read call is
interpreted as a write call by 8-bit eeproms).
*/
return 0;
}
dev->i2c_client.addr = 0xa0 >> 1;
/* Check if board has eeprom */
err = i2c_master_recv(&dev->i2c_client, &buf, 0);
if (err < 0) {
em28xx_errdev("board has no eeprom\n");
memset(eedata, 0, len);
return -ENODEV;
}
buf = 0;
err = i2c_master_send(&dev->i2c_client, &buf, 1);
if (err != 1) {
printk(KERN_INFO "%s: Huh, no eeprom present (err=%d)?\n",
dev->name, err);
return err;
}
if (dev->board.is_em2800)
block_max = 4;
else
block_max = 64;
while (size > 0) {
if (size > block_max)
block = block_max;
else
block = size;
if (block !=
(err = i2c_master_recv(&dev->i2c_client, p, block))) {
printk(KERN_WARNING
"%s: i2c eeprom read error (err=%d)\n",
dev->name, err);
return err;
}
size -= block;
p += block;
}
for (i = 0; i < len; i++) {
if (0 == (i % 16))
printk(KERN_INFO "%s: i2c eeprom %02x:", dev->name, i);
printk(" %02x", eedata[i]);
if (15 == (i % 16))
printk("\n");
}
if (em_eeprom->id == 0x9567eb1a)
dev->hash = em28xx_hash_mem(eedata, len, 32);
printk(KERN_INFO "%s: EEPROM ID= 0x%08x, EEPROM hash = 0x%08lx\n",
dev->name, em_eeprom->id, dev->hash);
printk(KERN_INFO "%s: EEPROM info:\n", dev->name);
switch (em_eeprom->chip_conf >> 4 & 0x3) {
case 0:
printk(KERN_INFO "%s:\tNo audio on board.\n", dev->name);
break;
case 1:
printk(KERN_INFO "%s:\tAC97 audio (5 sample rates)\n",
dev->name);
break;
case 2:
printk(KERN_INFO "%s:\tI2S audio, sample rate=32k\n",
dev->name);
break;
case 3:
printk(KERN_INFO "%s:\tI2S audio, 3 sample rates\n",
dev->name);
break;
}
if (em_eeprom->chip_conf & 1 << 3)
printk(KERN_INFO "%s:\tUSB Remote wakeup capable\n", dev->name);
if (em_eeprom->chip_conf & 1 << 2)
printk(KERN_INFO "%s:\tUSB Self power capable\n", dev->name);
switch (em_eeprom->chip_conf & 0x3) {
case 0:
printk(KERN_INFO "%s:\t500mA max power\n", dev->name);
break;
case 1:
printk(KERN_INFO "%s:\t400mA max power\n", dev->name);
break;
case 2:
printk(KERN_INFO "%s:\t300mA max power\n", dev->name);
break;
case 3:
printk(KERN_INFO "%s:\t200mA max power\n", dev->name);
break;
}
printk(KERN_INFO "%s:\tTable at 0x%02x, strings=0x%04x, 0x%04x, 0x%04x\n",
dev->name,
em_eeprom->string_idx_table,
em_eeprom->string1,
em_eeprom->string2,
em_eeprom->string3);
return 0;
}
/* ----------------------------------------------------------- */
/*
* functionality()
*/
static u32 functionality(struct i2c_adapter *adap)
{
struct em28xx *dev = adap->algo_data;
u32 func_flags = I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
if (dev->board.is_em2800)
func_flags &= ~I2C_FUNC_SMBUS_WRITE_BLOCK_DATA;
return func_flags;
}
static struct i2c_algorithm em28xx_algo = {
.master_xfer = em28xx_i2c_xfer,
.functionality = functionality,
};
static struct i2c_adapter em28xx_adap_template = {
.owner = THIS_MODULE,
.name = "em28xx",
.algo = &em28xx_algo,
};
static struct i2c_client em28xx_client_template = {
.name = "em28xx internal",
};
/* ----------------------------------------------------------- */
/*
* i2c_devs
* incomplete list of known devices
*/
static char *i2c_devs[128] = {
[0x4a >> 1] = "saa7113h",
[0x52 >> 1] = "drxk",
[0x60 >> 1] = "remote IR sensor",
[0x8e >> 1] = "remote IR sensor",
[0x86 >> 1] = "tda9887",
[0x80 >> 1] = "msp34xx",
[0x88 >> 1] = "msp34xx",
[0xa0 >> 1] = "eeprom",
[0xb0 >> 1] = "tda9874",
[0xb8 >> 1] = "tvp5150a",
[0xba >> 1] = "webcam sensor or tvp5150a",
[0xc0 >> 1] = "tuner (analog)",
[0xc2 >> 1] = "tuner (analog)",
[0xc4 >> 1] = "tuner (analog)",
[0xc6 >> 1] = "tuner (analog)",
};
/*
* do_i2c_scan()
* check i2c address range for devices
*/
void em28xx_do_i2c_scan(struct em28xx *dev)
{
u8 i2c_devicelist[128];
unsigned char buf;
int i, rc;
memset(i2c_devicelist, 0, ARRAY_SIZE(i2c_devicelist));
for (i = 0; i < ARRAY_SIZE(i2c_devs); i++) {
dev->i2c_client.addr = i;
rc = i2c_master_recv(&dev->i2c_client, &buf, 0);
if (rc < 0)
continue;
i2c_devicelist[i] = i;
printk(KERN_INFO "%s: found i2c device @ 0x%x [%s]\n",
dev->name, i << 1, i2c_devs[i] ? i2c_devs[i] : "???");
}
dev->i2c_hash = em28xx_hash_mem(i2c_devicelist,
ARRAY_SIZE(i2c_devicelist), 32);
}
/*
* em28xx_i2c_register()
* register i2c bus
*/
int em28xx_i2c_register(struct em28xx *dev)
{
int retval;
BUG_ON(!dev->em28xx_write_regs || !dev->em28xx_read_reg);
BUG_ON(!dev->em28xx_write_regs_req || !dev->em28xx_read_reg_req);
dev->i2c_adap = em28xx_adap_template;
dev->i2c_adap.dev.parent = &dev->udev->dev;
strcpy(dev->i2c_adap.name, dev->name);
dev->i2c_adap.algo_data = dev;
i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev);
retval = i2c_add_adapter(&dev->i2c_adap);
if (retval < 0) {
em28xx_errdev("%s: i2c_add_adapter failed! retval [%d]\n",
__func__, retval);
return retval;
}
dev->i2c_client = em28xx_client_template;
dev->i2c_client.adapter = &dev->i2c_adap;
retval = em28xx_i2c_eeprom(dev, dev->eedata, sizeof(dev->eedata));
if ((retval < 0) && (retval != -ENODEV)) {
em28xx_errdev("%s: em28xx_i2_eeprom failed! retval [%d]\n",
__func__, retval);
return retval;
}
if (i2c_scan)
em28xx_do_i2c_scan(dev);
return 0;
}
/*
* em28xx_i2c_unregister()
* unregister i2c_bus
*/
int em28xx_i2c_unregister(struct em28xx *dev)
{
i2c_del_adapter(&dev->i2c_adap);
return 0;
}