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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Lars-Peter Clausen <lars@metafoo.de>
Cc: Michael Hennerich <Michael.Hennerich@analog.com>,
	Jonathan Cameron <jic23@kernel.org>,
	Hartmut Knaack <knaack.h@gmx.de>,
	Peter Meerwald <pmeerw@pmeerw.net>,
	linux-iio@vger.kernel.org, kernel-janitors@vger.kernel.org,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>
Subject: [patch] iio: imu: adis16400: Fix sign extension
Date: Fri, 30 Jan 2015 08:30:59 +0000	[thread overview]
Message-ID: <20150130083058.GD21357@mwanda> (raw)

Because of C's type promotion rules, the code shifts in
"((val16 & 0xFFF) << 4) >> 4;" cancel each other out and they're a
no-op.

The intention here was to sign-extend then 11th bit so we can use the
sign_extend32() function.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Please review this carefully.  I'm pretty sure it's correct but this is
the first time I've ever used the sign_extend32() function.

diff --git a/drivers/iio/imu/adis16400_core.c b/drivers/iio/imu/adis16400_core.c
index b70873d..ed636c9 100644
--- a/drivers/iio/imu/adis16400_core.c
+++ b/drivers/iio/imu/adis16400_core.c
@@ -414,7 +414,7 @@ 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:

WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Lars-Peter Clausen <lars@metafoo.de>
Cc: Michael Hennerich <Michael.Hennerich@analog.com>,
	Jonathan Cameron <jic23@kernel.org>,
	Hartmut Knaack <knaack.h@gmx.de>,
	Peter Meerwald <pmeerw@pmeerw.net>,
	linux-iio@vger.kernel.org, kernel-janitors@vger.kernel.org,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>
Subject: [patch] iio: imu: adis16400: Fix sign extension
Date: Fri, 30 Jan 2015 11:30:59 +0300	[thread overview]
Message-ID: <20150130083058.GD21357@mwanda> (raw)

Because of C's type promotion rules, the code shifts in
"((val16 & 0xFFF) << 4) >> 4;" cancel each other out and they're a
no-op.

The intention here was to sign-extend then 11th bit so we can use the
sign_extend32() function.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Please review this carefully.  I'm pretty sure it's correct but this is
the first time I've ever used the sign_extend32() function.

diff --git a/drivers/iio/imu/adis16400_core.c b/drivers/iio/imu/adis16400_core.c
index b70873d..ed636c9 100644
--- a/drivers/iio/imu/adis16400_core.c
+++ b/drivers/iio/imu/adis16400_core.c
@@ -414,7 +414,7 @@ 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:

             reply	other threads:[~2015-01-30  8:30 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-30  8:30 Dan Carpenter [this message]
2015-01-30  8:30 ` [patch] iio: imu: adis16400: Fix sign extension Dan Carpenter
2015-01-30  8:34 ` Lars-Peter Clausen
2015-01-30  8:34   ` Lars-Peter Clausen
2015-01-30  9:22   ` Dan Carpenter
2015-01-30  9:22     ` Dan Carpenter
2015-01-30  9:31     ` Rasmus Villemoes
2015-01-30  9:31       ` Rasmus Villemoes
2015-01-30 10:23       ` Dan Carpenter
2015-01-30 10:23         ` Dan Carpenter
  -- strict thread matches above, loose matches on Subject: below --
2015-01-22 23:34 [PATCH] " Rasmus Villemoes
2015-01-23  8:56 ` Lars-Peter Clausen
2015-01-26 21:07   ` Jonathan Cameron

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