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>
Signed-off-by: Jonathan Santos <Jonathan.Santos@xxxxxxxxxx>
Cc: <Stable@xxxxxxxxxxxxxxx>
Link: https://patch.msgid.link/505994d3b71c2aa38ba714d909a68e021f12124c.1741268122.git.Jonathan.Santos@xxxxxxxxxx
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
---
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 ea829c51e80b..09e7cccfd51c 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(indio_dev);
if (ret < 0)
return ret;
- *val = ret;
+ *val = sign_extend32(ret, chan->scan_type.realbits - 1);
return IIO_VAL_INT;
--
2.48.1
