On Mon, 27 Jan 2025 12:11:01 -0300
Jonathan Santos <Jonathan.Santos@xxxxxxxxxx> wrote:
> From: Sergiu Cuciurean <sergiu.cuciurean@xxxxxxxxxx>
>
> The ad7768-1 ADC output code is two's complement, meaning that the voltage
> conversion result is a signed value.. Since the value is a 24 bit one,
> stored in a 32 bit variable, the sign should be extended in order to get
> the correct representation.
>
> Also the channel description has been updated to signed representation,
> to match the ADC specifications.
>
> Fixes: a5f8c7da3dbe ("iio: adc: Add AD7768-1 ADC basic support")
> Reviewed-by: David Lechner <dlechner@xxxxxxxxxxxx>
> Reviewed-by: Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx>
> Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@xxxxxxxxxx>
> ---
> v2 Changes:
> * Patch moved to the start of the patch series.
Applied to the fixes-togreg branch of iio.git.
Thanks,
Jonathan
> ---
> drivers/iio/adc/ad7768-1.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
> index 113703fb7245..c3cf04311c40 100644
> --- a/drivers/iio/adc/ad7768-1.c
> +++ b/drivers/iio/adc/ad7768-1.c
> @@ -142,7 +142,7 @@ static const struct iio_chan_spec ad7768_channels[] = {
> .channel = 0,
> .scan_index = 0,
> .scan_type = {
> - .sign = 'u',
> + .sign = 's',
> .realbits = 24,
> .storagebits = 32,
> .shift = 8,
> @@ -371,7 +371,7 @@ static int ad7768_read_raw(struct iio_dev *indio_dev,
>
> ret = ad7768_scan_direct(indio_dev);
> if (ret >= 0)
> - *val = ret;
> + *val = sign_extend32(ret, chan->scan_type.realbits - 1);
>
> iio_device_release_direct_mode(indio_dev);
> if (ret < 0)
