[PATCH AUTOSEL 4.14 004/103] iio: dac: mcp4922: fix error handling in mcp4922_write_raw

Sasha Levin
2019-11-08T11:43:28Z

From: Marcus Folkesson <marcus.folkesson@gmail.com>

[ Upstream commit 0833627fc3f757a0dca11e2a9c46c96335a900ee ]

Do not try to write negative values and make sure that the write goes well.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iio/dac/mcp4922.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/dac/mcp4922.c b/drivers/iio/dac/mcp4922.c
index 3854d201a5d6c..68dd0be1ac076 100644
--- a/drivers/iio/dac/mcp4922.c
+++ b/drivers/iio/dac/mcp4922.c
@@ -94,17 +94,22 @@ static int mcp4922_write_raw(struct iio_dev *indio_dev,
long mask)
{
struct mcp4922_state *state = iio_priv(indio_dev);
+ int ret;

if (val2 != 0)
return -EINVAL;

switch (mask) {
case IIO_CHAN_INFO_RAW:
- if (val > GENMASK(chan->scan_type.realbits-1, 0))
+ if (val < 0 || val > GENMASK(chan->scan_type.realbits - 1, 0))
return -EINVAL;
val <<= chan->scan_type.shift;
- state->value[chan->channel] = val;
- return mcp4922_spi_write(state, chan->channel, val);
+
+ ret = mcp4922_spi_write(state, chan->channel, val);
+ if (!ret)
+ state->value[chan->channel] = val;
+ return ret;
+
default:
return -EINVAL;
}
--
2.20.1