[PATCH 3.19 061/177] iio: imu: adis16400: Fix sign extension

[Greg Kroah-Hartman]

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

------------------

From: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>

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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/iio/imu/adis16400_core.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- 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
 		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:


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