From: Wilfried Wessner wilfried.wessner@gmail.com
commit f890987fac8153227258121740a9609668c427f3 upstream.
Fixes a wrong bit mask used for the ADC's result, which was caused by an improper usage of the GENMASK() macro. The bits higher than ADC's resolution are undefined and if not masked out correctly, a wrong result can be given. The GENMASK() macro indexing is zero based, so the mask has to go from [resolution - 1 , 0].
Fixes: 7f40e0614317f ("iio:adc:ad7949: Add AD7949 ADC driver family") Signed-off-by: Wilfried Wessner wilfried.wessner@gmail.com Reviewed-by: Andy Shevchenko andy.shevchenko@gmail.com Reviewed-by: Charles-Antoine Couret charles-antoine.couret@essensium.com Cc: Stable@vger.kernel.org Link: https://lore.kernel.org/r/20210208142705.GA51260@ubuntu Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iio/adc/ad7949.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/iio/adc/ad7949.c +++ b/drivers/iio/adc/ad7949.c @@ -91,7 +91,7 @@ static int ad7949_spi_read_channel(struc int ret; int i; int bits_per_word = ad7949_adc->resolution; - int mask = GENMASK(ad7949_adc->resolution, 0); + int mask = GENMASK(ad7949_adc->resolution - 1, 0); struct spi_message msg; struct spi_transfer tx[] = { {