diff options
| author | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2018-03-01 12:54:06 -0500 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2018-03-06 04:50:41 -0500 |
| commit | cf68c22f106369f6124342c58c4a50f07edd2174 (patch) | |
| tree | 33c4836505f94a9c3f1e309e6b6471497505773a /drivers/media/usb/em28xx/em28xx-i2c.c | |
| parent | 0108ae7fd2972707cde3fafa6fec555c50c64e28 (diff) | |
media: em28xx: adjust I2C timeout according with I2C speed
If the I2C speed is too slow, it should wait more for an
answer.
While here, change disconnected type from char to unsigned
int, just like all other bitmask fields there at em28xx
struct.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'drivers/media/usb/em28xx/em28xx-i2c.c')
| -rw-r--r-- | drivers/media/usb/em28xx/em28xx-i2c.c | 36 |
1 files changed, 33 insertions, 3 deletions
diff --git a/drivers/media/usb/em28xx/em28xx-i2c.c b/drivers/media/usb/em28xx/em28xx-i2c.c index 9ad958004990..fc90f5a32255 100644 --- a/drivers/media/usb/em28xx/em28xx-i2c.c +++ b/drivers/media/usb/em28xx/em28xx-i2c.c @@ -52,12 +52,42 @@ MODULE_PARM_DESC(i2c_debug, "i2c debug message level (1: normal debug, 2: show I /* + * Time in msecs to wait for i2c xfers to finish. + * 35ms is the maximum time a SMBUS device could wait when + * clock stretching is used. As the transfer itself will take + * some time to happen, set it to 35 ms. + * + * Ok, I2C doesn't specify any limit. So, eventually, we may need + * to increase this timeout. + */ +#define EM28XX_I2C_XFER_TIMEOUT 35 /* ms */ + +static int em28xx_i2c_timeout(struct em28xx *dev) +{ + int time = EM28XX_I2C_XFER_TIMEOUT; + + switch (dev->i2c_speed & 0x03) { + case EM28XX_I2C_FREQ_25_KHZ: + time += 4; /* Assume 4 ms for transfers */ + break; + case EM28XX_I2C_FREQ_100_KHZ: + case EM28XX_I2C_FREQ_400_KHZ: + time += 1; /* Assume 1 ms for transfers */ + break; + default: /* EM28XX_I2C_FREQ_1_5_MHZ */ + break; + } + + return msecs_to_jiffies(time); +} + +/* * 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) { - unsigned long timeout = jiffies + msecs_to_jiffies(EM28XX_I2C_XFER_TIMEOUT); + unsigned long timeout = jiffies + em28xx_i2c_timeout(dev); int ret; u8 b2[6]; @@ -110,7 +140,7 @@ static int em2800_i2c_send_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len) */ static int em2800_i2c_recv_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len) { - unsigned long timeout = jiffies + msecs_to_jiffies(EM28XX_I2C_XFER_TIMEOUT); + unsigned long timeout = jiffies + em28xx_i2c_timeout(dev); u8 buf2[4]; int ret; int i; @@ -186,7 +216,7 @@ static int em2800_i2c_check_for_device(struct em28xx *dev, u8 addr) static int em28xx_i2c_send_bytes(struct em28xx *dev, u16 addr, u8 *buf, u16 len, int stop) { - unsigned long timeout = jiffies + msecs_to_jiffies(EM28XX_I2C_XFER_TIMEOUT); + unsigned long timeout = jiffies + em28xx_i2c_timeout(dev); int ret; if (len < 1 || len > 64) |