From: Wilfried Wessner <wilfried.wessner@gmail.com>
To: Lars-Peter Clausen <lars@metafoo.de>,
Michael Hennerich <Michael.Hennerich@analog.com>,
Jonathan Cameron <jic23@kernel.org>,
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Cc: linux-iio@vger.kernel.org, gregkh@linuxfoundation.org
Subject: [PATCH] drivers: fixes wrong ADC result due to incorrect bit mask of ad7949 driver
Date: Sat, 6 Feb 2021 09:06:10 +0100 [thread overview]
Message-ID: <20210206080610.GA596506@ubuntu> (raw)
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].
Signed-off-by: Wilfried Wessner <wilfried.wessner@gmail.com>
---
drivers/iio/adc/ad7949.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iio/adc/ad7949.c b/drivers/iio/adc/ad7949.c
index 5d597e5050f6..a5b4858cb6dc 100644
--- a/drivers/iio/adc/ad7949.c
+++ b/drivers/iio/adc/ad7949.c
@@ -91,7 +91,7 @@ static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val,
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[] = {
{
--
2.25.1
reply other threads:[~2021-02-06 8:07 UTC|newest]
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