iio: imu: adis16400: Fix sign extension

The intention is obviously to sign-extend a 12 bit quantity. But
because of C's promotion rules, the assignment is equivalent to "val16
&= 0xfff;". Use the proper API for this.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/imu/adis16400_core.c b/drivers/iio/imu/adis16400_core.c
index b70873de04ea50a7cb73f34835f15c43ceff9eb1..fa795dcd5f75ec0a1e8de143bc0122ef36bf9409 100644 (file)
--- a/drivers/iio/imu/adis16400_core.c
+++ b/drivers/iio/imu/adis16400_core.c
@@ -26,6 +26,7 @@
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/debugfs.h>
+#include <linux/bitops.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
@@ -414,7 +415,7 @@ static int adis16400_read_raw(struct iio_dev *indio_dev,
                mutex_unlock(&indio_dev->mlock);
                if (ret)
                        return ret;
-               val16 = ((val16 & 0xFFF) << 4) >> 4;
+               val16 = sign_extend32(val16, 11);
                *val = val16;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_OFFSET: