iio: adc: ad7124: fix division by zero in ad7124_set_channel_odr()

In the ad7124_write_raw() function, parameter val can potentially
be zero. This may lead to a division by zero when DIV_ROUND_CLOSEST()
is called within ad7124_set_channel_odr(). The ad7124_write_raw()
function is invoked through the sequence: iio_write_channel_raw() ->
iio_write_channel_attribute() -> iio_channel_write(), with no checks
in place to ensure val is non-zero.

Cc: [email protected]
Fixes: 7b8d045 ("iio: adc: ad7124: allow more than 8 channels")
Signed-off-by: Zicheng Qu <[email protected]>
Reviewed-by: Nuno Sa <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jonathan Cameron <[email protected]>

Author: Zicheng Qu

drivers/iio/adc/ad7124.c

@@ -637,7 +637,7 @@ static int ad7124_write_raw(struct iio_dev *indio_dev,
 
 	switch (info) {
 	case IIO_CHAN_INFO_SAMP_FREQ:
-		if (val2 != 0) {
+		if (val2 != 0 || val == 0) {
 			ret = -EINVAL;
 			break;
 		}