5.4-stable review patch. If anyone has any objections, please let me know.
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From: Sergiu Cuciurean sergiu.cuciurean@analog.com
[ 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: a5f8c7da3dbe ("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... Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 9b9956c0b076f..c1adb95f2a464 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, @@ -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;