diff mbox series

[v11,07/15] iio: afe: rescale: use s64 for temporary scale calculations

Message ID 20211222034646.222189-8-liambeguin@gmail.com (mailing list archive)
State Changes Requested
Headers show
Series iio: afe: add temperature rescaling support | expand

Commit Message

Liam Beguin Dec. 22, 2021, 3:46 a.m. UTC 
From: Liam Beguin <lvb@xiphos.com>

All four scaling coefficients can take signed values.
Make tmp a signed 64-bit integer and switch to div_s64() to preserve
signs during 64-bit divisions.

Signed-off-by: Liam Beguin <lvb@xiphos.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
---
 drivers/iio/afe/iio-rescale.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

Andy Shevchenko Dec. 22, 2021, 12:25 p.m. UTC | #1 
On Wed, Dec 22, 2021 at 5:47 AM Liam Beguin <liambeguin@gmail.com> wrote:
>
> From: Liam Beguin <lvb@xiphos.com>
>
> All four scaling coefficients can take signed values.
> Make tmp a signed 64-bit integer and switch to div_s64() to preserve
> signs during 64-bit divisions.

Sounds to me like a fix with all necessary stuff needed about it:
- Fixes tag
- moving to the beginning of the series, where other fixes are
Liam Beguin Dec. 22, 2021, 6:21 p.m. UTC | #2 
On Wed, Dec 22, 2021 at 02:25:31PM +0200, Andy Shevchenko wrote:
> On Wed, Dec 22, 2021 at 5:47 AM Liam Beguin <liambeguin@gmail.com> wrote:
> >
> > From: Liam Beguin <lvb@xiphos.com>
> >
> > All four scaling coefficients can take signed values.
> > Make tmp a signed 64-bit integer and switch to div_s64() to preserve
> > signs during 64-bit divisions.
> 
> Sounds to me like a fix with all necessary stuff needed about it:
> - Fixes tag
> - moving to the beginning of the series, where other fixes are

Will do

> -- 
> With Best Regards,
> Andy Shevchenko
diff mbox series

Patch

diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c
index 6a2d4ae80652..a7297b4ba17e 100644
--- a/drivers/iio/afe/iio-rescale.c
+++ b/drivers/iio/afe/iio-rescale.c
@@ -22,7 +22,7 @@ 
 int rescale_process_scale(struct rescale *rescale, int scale_type,
 			  int *val, int *val2)
 {
-	unsigned long long tmp;
+	s64 tmp;
 	s32 rem;
 	u32 mult;
 	u32 neg;
@@ -39,10 +39,10 @@  int rescale_process_scale(struct rescale *rescale, int scale_type,
 		*val2 = rescale->denominator;
 		return IIO_VAL_FRACTIONAL;
 	case IIO_VAL_FRACTIONAL_LOG2:
-		tmp = *val * 1000000000LL;
-		do_div(tmp, rescale->denominator);
+		tmp = (s64)*val * 1000000000LL;
+		tmp = div_s64(tmp, rescale->denominator);
 		tmp *= rescale->numerator;
-		do_div(tmp, 1000000000LL);
+		tmp = div_s64(tmp, 1000000000LL);
 		*val = tmp;
 		return scale_type;
 	case IIO_VAL_INT_PLUS_NANO: