Re: [PATCH 13/22] iio: dac: ad5686: fix input raw value check

[Jonathan Cameron <jic23@kernel.org>]

On Wed, 22 Apr 2026 15:45:47 +0100
Rodrigo Alencar via B4 Relay <devnull+rodrigo.alencar.analog.com@kernel.org> wrote:

> From: Rodrigo Alencar <rodrigo.alencar@analog.com>
> 
> Use in_range() to fix range check for input raw value, which is off by
> one, i.e., for a 10-bit DAC the max valid value is 1023, but 1 << 10
> equals 1024, which passes the previous check, allowing an out-of-range
> write.
> 
> Signed-off-by: Rodrigo Alencar <rodrigo.alencar@analog.com>
> ---
>  drivers/iio/dac/ad5686.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/dac/ad5686.c b/drivers/iio/dac/ad5686.c
> index 19d791c655b7..07a944311f0e 100644
> --- a/drivers/iio/dac/ad5686.c
> +++ b/drivers/iio/dac/ad5686.c
> @@ -185,7 +185,7 @@ static int ad5686_write_raw(struct iio_dev *indio_dev,
>  
>  	switch (mask) {
>  	case IIO_CHAN_INFO_RAW:
> -		if (val > (1 << chan->scan_type.realbits) || val < 0)
> +		if (!in_range(val, 0, 1 << chan->scan_type.realbits))

Might just be me, but I do find in range a bit weird when the offset is 0.

I'd be tempted to just make the check >=
 
>  			return -EINVAL;
>  
>  		mutex_lock(&st->lock);
>