diff options
| author | David Lechner <dlechner@baylibre.com> | 2025-05-05 13:28:40 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-06-27 11:11:26 +0100 |
| commit | aaa25db0b8a3571ee8eb0829a32fa16cf6efa15e (patch) | |
| tree | 3327226e9647b389e9ef0aedc5d483c2ac5bf7fd | |
| parent | ea66a9effa4850b889f34ffebb7d735cc16d34a5 (diff) | |
iio: adc: ad7944: mask high bits on direct read
commit 7cdfbc0113d087348b8e65dd79276d0f57b89a10 upstream.
Apply a mask to the raw value received over the SPI bus for unsigned
direct reads. As we found recently, SPI controllers may not set unused
bits to 0 when reading with bits_per_word != {8,16,32}. The ad7944 uses
bits_per_word of 14 and 18, so we need to mask the value to be sure we
returning the correct value to userspace during a direct read.
Fixes: d1efcf8871db ("iio: adc: ad7944: add driver for AD7944/AD7985/AD7986")
Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://patch.msgid.link/20250505-iio-adc-ad7944-max-high-bits-on-direct-read-v1-1-b173facceefe@baylibre.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/iio/adc/ad7944.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/iio/adc/ad7944.c b/drivers/iio/adc/ad7944.c index 58a25792cec37..1e2cf512c2f5f 100644 --- a/drivers/iio/adc/ad7944.c +++ b/drivers/iio/adc/ad7944.c @@ -290,6 +290,8 @@ static int ad7944_single_conversion(struct ad7944_adc *adc, if (chan->scan_type.sign == 's') *val = sign_extend32(*val, chan->scan_type.realbits - 1); + else + *val &= GENMASK(chan->scan_type.realbits - 1, 0); return IIO_VAL_INT; } |