I2C read operations can also take some time to happen.
Try again, if it fails with return code different than 0x10
until timeout.
Signed-off-by: Mauro Carvalho Chehab <m.che...@samsung.com>
---
drivers/media/usb/em28xx/em28xx-i2c.c | 62 +++++++++++++++++++----------------
1 file changed, 34 insertions(+), 28 deletions(-)
diff --git a/drivers/media/usb/em28xx/em28xx-i2c.c
b/drivers/media/usb/em28xx/em28xx-i2c.c
index e030e0b7d645..6cd3d909bb3a 100644
--- a/drivers/media/usb/em28xx/em28xx-i2c.c
+++ b/drivers/media/usb/em28xx/em28xx-i2c.c
@@ -237,6 +237,7 @@ static int em28xx_i2c_send_bytes(struct em28xx *dev, u16
addr, u8 *buf,
*/
static int em28xx_i2c_recv_bytes(struct em28xx *dev, u16 addr, u8 *buf, u16
len)
{
+ unsigned long timeout = jiffies +
msecs_to_jiffies(EM2800_I2C_XFER_TIMEOUT);
int ret;
if (len < 1 || len > 64)
@@ -246,39 +247,44 @@ static int em28xx_i2c_recv_bytes(struct em28xx *dev, u16
addr, u8 *buf, u16 len)
* 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 < 0) {
- em28xx_warn("reading from i2c device at 0x%x failed
(error=%i)\n",
- addr, ret);
- return ret;
- }
- /*
- * NOTE: some devices with two i2c busses have the bad habit to return 0
- * bytes if we are on bus B AND there was no write attempt to the
- * specified slave address before AND no device is present at the
- * requested slave address.
- * Anyway, the next check will fail with -EREMOTEIO in this case, so
avoid
- * spamming the system log on device probing and do nothing here.
- */
+ do {
+ /* Read data from i2c device */
+ ret = dev->em28xx_read_reg_req_len(dev, 2, addr, buf, len);
+ if (ret < 0) {
+ em28xx_warn("reading from i2c device at 0x%x failed
(error=%i)\n",
+ addr, ret);
+ return ret;
+ }
+ /*
+ * NOTE: some devices with two i2c busses have the bad habit to
return 0
+ * bytes if we are on bus B AND there was no write attempt to the
+ * specified slave address before AND no device is present at the
+ * requested slave address.
+ * Anyway, the next check will fail with -EREMOTEIO in this
case, so avoid
+ * spamming the system log on device probing and do nothing here.
+ */
+
+ /* Check success of the i2c operation */
+ ret = dev->em28xx_read_reg(dev, 0x05);
+ if (ret == 0) /* success */
+ return len;
+ if (ret < 0) {
+ em28xx_warn("failed to get i2c transfer status from
bridge register (error=%i)\n",
+ ret);
+ return ret;
+ }
+ if (ret != 0x10)
+ break;
+ msleep(5);
+ } while (time_is_after_jiffies(timeout));
- /* Check success of the i2c operation */
- ret = dev->em28xx_read_reg(dev, 0x05);
- if (ret == 0) /* success */
- return len;
- if (ret < 0) {
- em28xx_warn("failed to get i2c transfer status from bridge
register (error=%i)\n",
- ret);
- return ret;
- }
if (ret == 0x10) {
if (i2c_debug)
- em28xx_warn("I2C transfer timeout on writing to addr
0x%02x",
+ em28xx_warn("I2C transfer timeout on reading from addr
0x%02x",
addr);
- return -EREMOTEIO;
+ } else {
+ em28xx_warn("unknown i2c error (status=%i)\n", ret);
}
-
- em28xx_warn("unknown i2c error (status=%i)\n", ret);
return -EREMOTEIO;
}
--
1.8.3.1
--
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