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

Greg Kroah-Hartman
2015-03-16T15:44:51Z

From: Rasmus Villemoes <linux@rasmusvillemoes.dk>

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@rasmusvillemoes.dk>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
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;