Re: [PATCH 1/5] iio: adc: ad4030: check scan_type for error

[Nuno Sá]

On Mon, 2025-03-10 at 15:43 -0500, David Lechner wrote:
> Check scan_type for error ad4030_get_chan_scale(). Currently, this
> should never fail, but it is good practice to always check for errors
> in case of future changes.
> 
> Calling iio_get_current_scan_type() is moved out of the if statement
> also to avoid potential issues with future changes instead of assuming
> that the non-differential case does not use extended scan_type.
> 
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Closes: https://lore.kernel.org/r/202503040954.n6MhjSsV-lkp@xxxxxxxxx/
> Signed-off-by: David Lechner <dlechner@xxxxxxxxxxxx>
> ---

Reviewed-by: Nuno Sá <nuno.sa@xxxxxxxxxx>

>  drivers/iio/adc/ad4030.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/adc/ad4030.c b/drivers/iio/adc/ad4030.c
> index
> 9a020680885d93f4da8922e5cfeecc0c7ce23f4d..af7a817e8273496e8856a5ba1a9c2e66a11f
> 0a84 100644
> --- a/drivers/iio/adc/ad4030.c
> +++ b/drivers/iio/adc/ad4030.c
> @@ -390,16 +390,18 @@ static int ad4030_get_chan_scale(struct iio_dev
> *indio_dev,
>  	struct ad4030_state *st = iio_priv(indio_dev);
>  	const struct iio_scan_type *scan_type;
>  
> +	scan_type = iio_get_current_scan_type(indio_dev, st->chip->channels);
> +	if (IS_ERR(scan_type))
> +		return PTR_ERR(scan_type);
> +
>  	if (chan->differential) {
> -		scan_type = iio_get_current_scan_type(indio_dev,
> -						      st->chip->channels);
>  		*val = (st->vref_uv * 2) / MILLI;
>  		*val2 = scan_type->realbits;
>  		return IIO_VAL_FRACTIONAL_LOG2;
>  	}
>  
>  	*val = st->vref_uv / MILLI;
> -	*val2 = chan->scan_type.realbits;
> +	*val2 = scan_type->realbits;
>  	return IIO_VAL_FRACTIONAL_LOG2;
>  }
>  
>