Re: [PATCH 05/12] iio: dac: rohm-bd79703: Do not allow writing SCALE

On Mon, 10 Aug 2026 10:51:38 +0300
Matti Vaittinen <[email protected]> wrote:

> From: Matti Vaittinen <[email protected]>
> 
> The BD79703 has adds IIO_CHAN_INFO_SCALE in the info_mask_shared_by_type
> so users can read the scale, which depends on the used reference
> voltage. This, however, enables users to try writing the scale as well.
> This isn't really supported but the bd79703_write_raw() does not check
> the mask, and if written scale values pass the validation, the driver
> will proceed writing the DAC value when users writes the scale.
> 
> Prevent the unsupported scale setting and return an error.
> 
> Signed-off-by: Matti Vaittinen <[email protected]>
> Fixes: af6aca656a85 ("iio: dac: Support ROHM BD79703 DAC")

Applied.  

BTW convention is Fixes goes before SoB.
I did wonder if is documented anywhere and claude sent me
to the tip docs.
https://www.kernel.org/doc/Documentation/process/maintainer-tip.rst

IIO can follow that.

Anyhow, I'll swap them around whilst applying.

> ---
>  drivers/iio/dac/rohm-bd79703.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/iio/dac/rohm-bd79703.c b/drivers/iio/dac/rohm-bd79703.c
> index e91090e4a66d..68e66e7286d8 100644
> --- a/drivers/iio/dac/rohm-bd79703.c
> +++ b/drivers/iio/dac/rohm-bd79703.c
> @@ -73,6 +73,9 @@ static int bd79703_write_raw(struct iio_dev *idev,
>  {
>  	struct bd79703_data *data = iio_priv(idev);
>  
> +	if (mask != IIO_CHAN_INFO_RAW)
> +		return -EINVAL;
> +
>  	if (val < 0 || val >= 1 << BD79703_DAC_BITS)
>  		return -EINVAL;
>