This is a note to let you know that I've just added the patch titled
iio: adc: ad7768-1: Fix conversion result sign
to my char-misc git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git in the char-misc-next branch.
The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)
The patch will also be merged in the next major kernel release during the merge window.
If you have any questions about this process, please let me know.
From 8236644f5ecb180e80ad92d691c22bc509b747bb Mon Sep 17 00:00:00 2001 From: Sergiu Cuciurean sergiu.cuciurean@analog.com Date: Thu, 6 Mar 2025 18:00:29 -0300 Subject: iio: adc: ad7768-1: Fix conversion result sign
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 --- 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;