[PATCH v6 02/12] iio: dac: ad5686: fix input raw value check

Rodrigo Alencar via B4 Relay
2026-05-05T12:35:09Z

Fix range check for input raw value, which is off by one, i.e., for a
10-bit DAC the max valid value is 1023, but 1 << 10 equals 1024, which
passes the previous check, allowing an out-of-range write. The issue
exists since the ad5686 driver was first introduced.

Fixes: c2f37c8dcadc ("iio: dac: New driver for AD5686R, AD5685R, AD5684R Digital to analog converters")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Rodrigo Alencar <rodrigo.alencar@analog.com>
---
drivers/iio/dac/ad5686.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/dac/ad5686.c b/drivers/iio/dac/ad5686.c
index 1fc54c38b629..076fe8b8bd85 100644
--- a/drivers/iio/dac/ad5686.c
+++ b/drivers/iio/dac/ad5686.c
@@ -154,7 +154,7 @@ static int ad5686_write_raw(struct iio_dev *indio_dev,

switch (mask) {
case IIO_CHAN_INFO_RAW:
- if (val > (1 << chan->scan_type.realbits) || val < 0)
+ if (val >= (1 << chan->scan_type.realbits) || val < 0)
return -EINVAL;

mutex_lock(&st->lock);

--
2.43.0