[PATCH 08/10] iio: dac: ad5686: fix input raw value check

[Rodrigo Alencar via B4 Relay]

From: Rodrigo Alencar <rodrigo.alencar@xxxxxxxxxx>

Use in_range() to 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")
Signed-off-by: Rodrigo Alencar <rodrigo.alencar@xxxxxxxxxx>
---
 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 040a24c62c9a..ab498ec2ed5c 100644
--- a/drivers/iio/dac/ad5686.c
+++ b/drivers/iio/dac/ad5686.c
@@ -186,7 +186,7 @@ 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 (!in_range(val, 0, 1 << chan->scan_type.realbits))
 			return -EINVAL;
 
 		return st->write(st, AD5686_CMD_WRITE_INPUT_N_UPDATE_N,

-- 
2.43.0