[PATCH 2/5] iio: dac: ad5758: Reject out-of-range raw values

[Arka Mondal <arka@arkamondal.net>]

ad5758_write_raw() passes the value from userspace straight to
ad5758_spi_reg_write(), which keeps only the low 16 bits. Writing -1
to the raw attribute gives full-scale output, and 65536 gives code 0.

Return -EINVAL for values outside 0 to U16_MAX, as ad5755 does.

Fixes: 28d1a7ac2a0d ("iio: dac: Add AD5758 support")
Signed-off-by: Arka Mondal <arka@arkamondal.net>
---

Notes:
    Compile tested only; no relevant hardware available.

 drivers/iio/dac/ad5758.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iio/dac/ad5758.c b/drivers/iio/dac/ad5758.c
index ba381bd252d1..2a9e907b5eb8 100644
--- a/drivers/iio/dac/ad5758.c
+++ b/drivers/iio/dac/ad5758.c
@@ -556,6 +556,9 @@ static int ad5758_write_raw(struct iio_dev *indio_dev,
 
 	switch (info) {
 	case IIO_CHAN_INFO_RAW:
+		if (val < 0 || val > U16_MAX)
+			return -EINVAL;
+
 		mutex_lock(&st->lock);
 		ret = ad5758_spi_reg_write(st, AD5758_DAC_INPUT, val);
 		mutex_unlock(&st->lock);
-- 
2.55.0