On Fri, 10 Mar 2023 19:22:48 -0500
William Breathitt Gray <william.gray@xxxxxxxxxx> wrote:
> The CIO-DAC series of devices only supports DAC values up to 12-bit
> rather than 16-bit. Trying to write a 16-bit value results in only the
> lower 12 bits affecting the DAC output which is not what the user
> expects. Instead, adjust the DAC write value check to reject values
> larger than 12-bit so that they fail explicitly as invalid for the user.
>
> Fixes: 3b8df5fd526e ("iio: Add IIO support for the Measurement Computing CIO-DAC family")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: William Breathitt Gray <william.gray@xxxxxxxxxx>
Applied to the fixes-togreg branch of iio.git.
Thanks,
Jonathan
> ---
> drivers/iio/dac/cio-dac.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/dac/cio-dac.c b/drivers/iio/dac/cio-dac.c
> index 791dd999cf29..18a64f72fc18 100644
> --- a/drivers/iio/dac/cio-dac.c
> +++ b/drivers/iio/dac/cio-dac.c
> @@ -66,8 +66,8 @@ static int cio_dac_write_raw(struct iio_dev *indio_dev,
> if (mask != IIO_CHAN_INFO_RAW)
> return -EINVAL;
>
> - /* DAC can only accept up to a 16-bit value */
> - if ((unsigned int)val > 65535)
> + /* DAC can only accept up to a 12-bit value */
> + if ((unsigned int)val > 4095)
> return -EINVAL;
>
> priv->chan_out_states[chan->channel] = val;
>
> base-commit: fe15c26ee26efa11741a7b632e9f23b01aca4cc6
