| Message ID | 20210603164729.3584702-1-jic23@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | iio: accel: sca3000: Use sign_extend32() instead of opencoding sign extension. | expand |
On Thu, 3 Jun 2021 17:47:29 +0100 Jonathan Cameron <jic23@kernel.org> 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> If someone could give this a quick sanity check that would be great. Thanks, Jonathan > --- > 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..0692ccb80293 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, 13); > } else { > /* get the temperature when available */ > ret = sca3000_read_data_short(st,
On Sun, 18 Jul 2021 16:16:12 +0100 Jonathan Cameron <jic23@kernel.org> wrote: > On Thu, 3 Jun 2021 17:47:29 +0100 > Jonathan Cameron <jic23@kernel.org> 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> > > If someone could give this a quick sanity check that would be great. > This one is still in the queue because I really don't like applying my own patches without anyone having sanity checked them... So if anyone has time to for a quick look that would be great. > Thanks, > > Jonathan > > > --- > > 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..0692ccb80293 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, 13); > > } else { > > /* get the temperature when available */ > > ret = sca3000_read_data_short(st, >
On 6/3/21 6:47 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> > --- > 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..0692ccb80293 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, 13); Should be 12 I think. The index is 0 based. > } else { > /* get the temperature when available */ > ret = sca3000_read_data_short(st,
On Sun, 3 Oct 2021 20:03:10 +0200 Lars-Peter Clausen <lars@metafoo.de> wrote: > On 6/3/21 6:47 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> > > --- > > 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..0692ccb80293 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, 13); > Should be 12 I think. The index is 0 based. Fine example of why everything needs a sanity check. Indeed, should be 12 to sign extend a 13bit value. Jonathan > > } else { > > /* get the temperature when available */ > > ret = sca3000_read_data_short(st, > >
diff --git a/drivers/iio/accel/sca3000.c b/drivers/iio/accel/sca3000.c index cb753a43533c..0692ccb80293 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, 13); } else { /* get the temperature when available */ ret = sca3000_read_data_short(st,