Re: [PATCH] media: i2c: upd64031a: add error handling for I2C read

[Hans Verkuil <hverkuil+cisco@kernel.org>]

On 3/31/26 15:20, Wenyuan Li wrote:
> In upd64031a_read(), i2c_master_recv() is called without checking
> its return value. If the I2C read fails, the function proceeds to
> return invalid data from the buffer.
> 
> Add proper error checking:
> - Check if all 2 bytes were read successfully
> - Log the error with %pe format
> - Return 0xff (the same as invalid register) on error

I'm not picking this up: it's not worth the effort, and this read is
used for debugging only. Failures won't hurt anything.

Ditto for your upd64083 patch.

Regards,

	Hans

> 
> Signed-off-by: Wenyuan Li <2063309626@qq.com>
> ---
>  drivers/media/i2c/upd64031a.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/i2c/upd64031a.c b/drivers/media/i2c/upd64031a.c
> index a178af46e695..ec9179cf9b69 100644
> --- a/drivers/media/i2c/upd64031a.c
> +++ b/drivers/media/i2c/upd64031a.c
> @@ -73,10 +73,19 @@ static u8 upd64031a_read(struct v4l2_subdev *sd, u8 reg)
>  {
>  	struct i2c_client *client = v4l2_get_subdevdata(sd);
>  	u8 buf[2];
> +	int ret;
>  
>  	if (reg >= sizeof(buf))
>  		return 0xff;
> -	i2c_master_recv(client, buf, 2);
> +
> +	ret = i2c_master_recv(client, buf, 2);
> +	if (ret != sizeof(buf)) {
> +		int err = ret < 0 ? ret : -EIO;
> +
> +		v4l2_err(sd, "I2C read failed: %pe\n", ERR_PTR(err));
> +		return 0xff;
> +	}
> +
>  	return buf[reg];
>  }
>