iio: adc: ad7768-1: Fix conversion result sign

[ Upstream commit 8236644f5ecb180e80ad92d691c22bc509b747bb ]

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: a5f8c7da3d ("iio: adc: Add AD7768-1 ADC basic support")
Reviewed-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
Cc: <Stable@vger.kernel.org>
Link: https://patch.msgid.link/505994d3b71c2aa38ba714d909a68e021f12124c.1741268122.git.Jonathan.Santos@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Sergiu Cuciurean
2025-03-06 18:00:29 -03:00
committed by Greg Kroah-Hartman
parent 28aadcb759
commit 6f21dfc4fa

View File

@@ -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,
@@ -374,7 +374,7 @@ static int ad7768_read_raw(struct iio_dev *indio_dev,
iio_device_release_direct_mode(indio_dev);
if (ret < 0)
return ret;
*val = ret;
*val = sign_extend32(ret, chan->scan_type.realbits - 1);
return IIO_VAL_INT;