[PATCH 3.12 103/175] iio: imu: adis16400: Fix sign extension

[Jiri Slaby]

From: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 19e353f2b344ad86cea6ebbc0002e5f903480a90 upstream.

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@xxxxxxxxxxxxxxxxxx>
Acked-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Signed-off-by: Jonathan Cameron <jic23@xxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 drivers/iio/imu/adis16400_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/imu/adis16400_core.c b/drivers/iio/imu/adis16400_core.c
index 7c582f7ae34e..70753bf23a86 100644
--- 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>
@@ -447,7 +448,7 @@ 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:
-- 
2.3.0

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