[PATCH v2] iio: accel: sca3000: Use sign_extend32() instead of opencoding sign extension.

[Jonathan Cameron <jic23@kernel.org>]

From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Whilst nice to get rid of this non obvious code, this also clears a
static checker warning:

drivers/iio/accel/sca3000.c:734 sca3000_read_raw()
warn: no-op. '((*val) << 19) >> 19'

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
v2: 
Use the right sign bit (thanks Lars!)
Should be bit 12 for a 13 bit value.

 drivers/iio/accel/sca3000.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/iio/accel/sca3000.c b/drivers/iio/accel/sca3000.c
index cb753a43533c..c6b75308148a 100644
--- a/drivers/iio/accel/sca3000.c
+++ b/drivers/iio/accel/sca3000.c
@@ -731,8 +731,7 @@ static int sca3000_read_raw(struct iio_dev *indio_dev,
 				return ret;
 			}
 			*val = (be16_to_cpup((__be16 *)st->rx) >> 3) & 0x1FFF;
-			*val = ((*val) << (sizeof(*val) * 8 - 13)) >>
-				(sizeof(*val) * 8 - 13);
+			*val = sign_extend32(*val, 12);
 		} else {
 			/* get the temperature when available */
 			ret = sca3000_read_data_short(st,
-- 
2.33.1