On Tue, Sep 28, 2021 at 10:57 PM Pekka Korpinen <pekka.korpinen@xxxxxx> wrote:
>
> On success i2c_master_send() returns the number of bytes written. The
> call from iio_write_channel_info(), however, expects the return value to
> be zero on success.
>
Requires a Fixes tag.
But other than that:
Reviewed-by: Alexandru Ardelean <ardeleanalex@xxxxxxxxx>
> Signed-off-by: Pekka Korpinen <pekka.korpinen@xxxxxx>
> ---
> This bug causes incorrect consumption of the sysfs buffer in
> iio_write_channel_info(). When writing more than two characters to
> out_voltage0_raw, the ad5446 write handler is called multiple times
> causing unexpected behavior.
>
> A similar fix was applied for ad5064.c in 2015 - commit 03fe472ef33b
> ("iio:ad5064: Make sure ad5064_i2c_write() returns 0 on success").
>
> drivers/iio/dac/ad5446.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/dac/ad5446.c b/drivers/iio/dac/ad5446.c
> index 488ec69967d6..dfd541bbde5b 100644
> --- a/drivers/iio/dac/ad5446.c
> +++ b/drivers/iio/dac/ad5446.c
> @@ -531,8 +531,13 @@ static int ad5622_write(struct ad5446_state *st, unsigned val)
> {
> struct i2c_client *client = to_i2c_client(st->dev);
> __be16 data = cpu_to_be16(val);
> + int ret;
> +
> + ret = i2c_master_send(client, (char *)&data, sizeof(data));
> + if (ret < 0)
> + return ret;
>
> - return i2c_master_send(client, (char *)&data, sizeof(data));
> + return 0;
> }
>
> /*
> --
> 2.33.0
>
