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Commit f7067a5a authored by Rasmus Villemoes's avatar Rasmus Villemoes Committed by Jonathan Cameron
Browse files

staging: iio: ad2s1200: Fix sign extension 



The line above makes vel a 12-bit quantity (st->rx[] is u8). The
intention is to sign-extend vel using bit 11 as the sign bit. But
because of C's promotion rules "vel = (vel << 4) >> 4;" is actually a
no-op, since vel is promoted to int before the inner
shift. sign_extend32 works equally well for 8 and 16 bits types, so
use that.

Signed-off-by: default avatarRasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 89bb35e2

drivers/staging/iio/resolver/ad2s1200.c

+2 −1
Original line number Original line Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/delay.h>

#include <linux/delay.h>

#include <linux/gpio.h>

#include <linux/gpio.h>

#include <linux/module.h>

#include <linux/module.h>

#include <linux/bitops.h>





#include <linux/iio/iio.h>

#include <linux/iio/iio.h>

#include <linux/iio/sysfs.h>

#include <linux/iio/sysfs.h>
@@ -68,7 +69,7 @@ static int ad2s1200_read_raw(struct iio_dev *indio_dev, 
		break;

		break;

	case IIO_ANGL_VEL:

	case IIO_ANGL_VEL:

		vel = (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);

		vel = (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);

		vel = (vel << 4) >> 4;

		vel = sign_extend32(vel, 11);

		*val = vel;

		*val = vel;

		break;

		break;

	default:

	default: