linux-kernel - [PATCH v2] staging:iio:accel:adis16240: sign extend function avoiding code duplication

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Date:   Tue, 12 Jun 2018 18:21:53 +0200
From:   Karim Eshapa <karim.eshapa@...il.com>
To:     lars@...afoo.de
Cc:     Michael.Hennerich@...log.com, jic23@...nel.org, knaack.h@....de,
        pmeerw@...erw.net, gregkh@...uxfoundation.org,
        linux-iio@...r.kernel.org, devel@...verdev.osuosl.org,
        linux-kernel@...r.kernel.org, Karim Eshapa <karim.eshapa@...il.com>
Subject: [PATCH v2] staging:iio:accel:adis16240: sign extend function avoiding code duplication

Use sign_extend32 kernel function instead of code duplication,
Safe also for 16 bit. and remove declaration of bits variable not needed.

Signed-off-by: Karim Eshapa <karim.eshapa@...il.com>

>On Tue, 2018-06-12 at 01:38 +0200, Karim Eshapa wrote:
>> Use sign_extend32 kernel function instead of code duplication.
>> Safe also for 16 bit.
>
>Perhaps remove the bits declaration and assignments
>and just use 9 directly.
>
>> diff --git a/drivers/staging/iio/accel/adis16240.c b/drivers/staging/iio/accel/adis16240.c
>
>> @@ -292,9 +292,7 @@ static int adis16240_read_raw(struct iio_dev *indio_dev,
>>               ret = adis_read_reg_16(st, addr, &val16);
>>               if (ret)
>>                       return ret;
>> -             val16 &= (1 << bits) - 1;
>> -             val16 = (s16)(val16 << (16 - bits)) >> (16 - bits);
>> -             *val = val16;
>> +             *val = sign_extend32(val16, bits - 1);
>>               return IIO_VAL_INT;
>>       case IIO_CHAN_INFO_PEAK:
>>               bits = 10;
>> @@ -302,9 +300,7 @@ static int adis16240_read_raw(struct iio_dev *indio_dev,
>>               ret = adis_read_reg_16(st, addr, &val16);
>>               if (ret)
>>                       return ret;
>> -             val16 &= (1 << bits) - 1;
>> -             val16 = (s16)(val16 << (16 - bits)) >> (16 - bits);
>> -             *val = val16;
>> +             *val = sign_extend32(val16, bits - 1);
>>               return IIO_VAL_INT;
>>       }
>>       return -EINVAL;
---
 drivers/staging/iio/accel/adis16240.c | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/drivers/staging/iio/accel/adis16240.c b/drivers/staging/iio/accel/adis16240.c
index fff6d99089cc..24e525f1ef25 100644
--- a/drivers/staging/iio/accel/adis16240.c
+++ b/drivers/staging/iio/accel/adis16240.c
@@ -250,7 +250,6 @@ static int adis16240_read_raw(struct iio_dev *indio_dev,
 {
 	struct adis *st = iio_priv(indio_dev);
 	int ret;
-	int bits;
 	u8 addr;
 	s16 val16;
 
@@ -287,24 +286,18 @@ static int adis16240_read_raw(struct iio_dev *indio_dev,
 		*val = 25000 / 244 - 0x133; /* 25 C = 0x133 */
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_CALIBBIAS:
-		bits = 10;
 		addr = adis16240_addresses[chan->scan_index][0];
 		ret = adis_read_reg_16(st, addr, &val16);
 		if (ret)
 			return ret;
-		val16 &= (1 << bits) - 1;
-		val16 = (s16)(val16 << (16 - bits)) >> (16 - bits);
-		*val = val16;
+		*val = sign_extend32(val16, 9);
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_PEAK:
-		bits = 10;
 		addr = adis16240_addresses[chan->scan_index][1];
 		ret = adis_read_reg_16(st, addr, &val16);
 		if (ret)
 			return ret;
-		val16 &= (1 << bits) - 1;
-		val16 = (s16)(val16 << (16 - bits)) >> (16 - bits);
-		*val = val16;
+		*val = sign_extend32(val16, 9);
 		return IIO_VAL_INT;
 	}
 	return -EINVAL;
-- 
2.17.1