Commit 546ce870 authored Mar 06, 2025 by Sergiu Cuciurean Committed by Greg Kroah-Hartman May 02, 2025

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: a5f8c7da ("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>

parent dcf1a808

drivers/iio/adc/ad7768-1.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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,
		@@ -373,7 +373,7 @@ 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;