[PATCH] media: af9035 I2C combined write + read transaction fix

[PATCH] media: af9035 I2C combined write + read transaction fix

[Alessandro Radicati]

This patch will modify the af9035 driver to use the register address
fields of the I2C read command for the combined write/read transaction
case.  Without this change, the firmware issues just a I2C read transaction
without the preceding write transaction to select the register.

Signed-off-by: Alessandro Radicati <alessandro@radicati.net>
---
 drivers/media/usb/dvb-usb-v2/af9035.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/media/usb/dvb-usb-v2/af9035.c b/drivers/media/usb/dvb-usb-v2/af9035.c
index 2638e32..09a549b 100644
--- a/drivers/media/usb/dvb-usb-v2/af9035.c
+++ b/drivers/media/usb/dvb-usb-v2/af9035.c
@@ -367,10 +367,25 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
 				memcpy(&buf[3], msg[0].buf, msg[0].len);
 			} else {
 				buf[1] = msg[0].addr << 1;
-				buf[2] = 0x00; /* reg addr len */
 				buf[3] = 0x00; /* reg addr MSB */
 				buf[4] = 0x00; /* reg addr LSB */
-				memcpy(&buf[5], msg[0].buf, msg[0].len);
+
+				/* Keep prev behavior for write req len > 2*/
+				if (msg[0].len > 2) {
+					buf[2] = 0x00; /* reg addr len */
+					memcpy(&buf[5], msg[0].buf, msg[0].len);
+
+				/* Use reg addr fields if write req len <= 2 */
+				} else {
+					req.wlen = 5;
+					buf[2] = msg[0].len;
+					if (msg[0].len == 2) {
+						buf[3] = msg[0].buf[0];
+						buf[4] = msg[0].buf[1];
+					} else if (msg[0].len == 1) {
+						buf[4] = msg[0].buf[0];
+					}
+				}
 			}
 			ret = af9035_ctrl_msg(d, &req);
 		}
-- 
2.5.0

Re: [PATCH] media: af9035 I2C combined write + read transaction fix

[Antti Palosaari]

Applied for 4.8, thanks!

Antti

On 04/06/2016 01:23 AM, Alessandro Radicati wrote:
> This patch will modify the af9035 driver to use the register address
> fields of the I2C read command for the combined write/read transaction
> case.  Without this change, the firmware issues just a I2C read transaction
> without the preceding write transaction to select the register.
>
> Signed-off-by: Alessandro Radicati <alessandro@radicati.net>
> ---
>  drivers/media/usb/dvb-usb-v2/af9035.c | 19 +++++++++++++++++--
>  1 file changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/usb/dvb-usb-v2/af9035.c b/drivers/media/usb/dvb-usb-v2/af9035.c
> index 2638e32..09a549b 100644
> --- a/drivers/media/usb/dvb-usb-v2/af9035.c
> +++ b/drivers/media/usb/dvb-usb-v2/af9035.c
> @@ -367,10 +367,25 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
>  				memcpy(&buf[3], msg[0].buf, msg[0].len);
>  			} else {
>  				buf[1] = msg[0].addr << 1;
> -				buf[2] = 0x00; /* reg addr len */
>  				buf[3] = 0x00; /* reg addr MSB */
>  				buf[4] = 0x00; /* reg addr LSB */
> -				memcpy(&buf[5], msg[0].buf, msg[0].len);
> +
> +				/* Keep prev behavior for write req len > 2*/
> +				if (msg[0].len > 2) {
> +					buf[2] = 0x00; /* reg addr len */
> +					memcpy(&buf[5], msg[0].buf, msg[0].len);
> +
> +				/* Use reg addr fields if write req len <= 2 */
> +				} else {
> +					req.wlen = 5;
> +					buf[2] = msg[0].len;
> +					if (msg[0].len == 2) {
> +						buf[3] = msg[0].buf[0];
> +						buf[4] = msg[0].buf[1];
> +					} else if (msg[0].len == 1) {
> +						buf[4] = msg[0].buf[0];
> +					}
> +				}
>  			}
>  			ret = af9035_ctrl_msg(d, &req);
>  		}
>

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