Re: [PATCH v2] iio: accel: sca3000: Use sign_extend32() instead of opencoding sign extension.

[Lars-Peter Clausen <lars@metafoo.de>]

On 10/17/21 6:03 PM, Jonathan Cameron wrote:
> From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>
> Whilst nice to get rid of this non obvious code, this also clears a
> static checker warning:
>
> drivers/iio/accel/sca3000.c:734 sca3000_read_raw()
> warn: no-op. '((*val) << 19) >> 19'
>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Reviewed-by: Lars-Peter Clausen <lars@metafoo.de

> ---
> v2:
> Use the right sign bit (thanks Lars!)
> Should be bit 12 for a 13 bit value.
>
>   drivers/iio/accel/sca3000.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/iio/accel/sca3000.c b/drivers/iio/accel/sca3000.c
> index cb753a43533c..c6b75308148a 100644
> --- a/drivers/iio/accel/sca3000.c
> +++ b/drivers/iio/accel/sca3000.c
> @@ -731,8 +731,7 @@ static int sca3000_read_raw(struct iio_dev *indio_dev,
>   				return ret;
>   			}
>   			*val = (be16_to_cpup((__be16 *)st->rx) >> 3) & 0x1FFF;
> -			*val = ((*val) << (sizeof(*val) * 8 - 13)) >>
> -				(sizeof(*val) * 8 - 13);
> +			*val = sign_extend32(*val, 12);
>   		} else {
>   			/* get the temperature when available */
>   			ret = sca3000_read_data_short(st,