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From: Liam Beguin <liambeguin@gmail.com>
To: liambeguin@gmail.com, peda@axentia.se, jic23@kernel.org,
	andy.shevchenko@gmail.com, lars@metafoo.de
Cc: linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org,
	devicetree@vger.kernel.org, robh+dt@kernel.org
Subject: [PATCH v11 07/15] iio: afe: rescale: use s64 for temporary scale calculations
Date: Tue, 21 Dec 2021 22:46:38 -0500	[thread overview]
Message-ID: <20211222034646.222189-8-liambeguin@gmail.com> (raw)
In-Reply-To: <20211222034646.222189-1-liambeguin@gmail.com>

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(-)

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:
-- 
2.34.0


  parent reply	other threads:[~2021-12-22  3:47 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-22  3:46 [PATCH v11 00/15] iio: afe: add temperature rescaling support Liam Beguin
2021-12-22  3:46 ` [PATCH v11 01/15] iio: inkern: apply consumer scale on IIO_VAL_INT cases Liam Beguin
2021-12-22  3:46 ` [PATCH v11 02/15] iio: inkern: apply consumer scale when no channel scale is available Liam Beguin
2021-12-22  3:46 ` [PATCH v11 03/15] iio: inkern: make a best effort on offset calculation Liam Beguin
2021-12-22  3:46 ` [PATCH v11 04/15] iio: afe: rescale: expose scale processing function Liam Beguin
2021-12-22 10:21   ` Andy Shevchenko
2021-12-22 18:20     ` Liam Beguin
2021-12-22 18:52       ` Andy Shevchenko
2021-12-22 19:42         ` Liam Beguin
2021-12-22 19:50           ` Andy Shevchenko
2021-12-22 20:04             ` Liam Beguin
2021-12-22  3:46 ` [PATCH v11 05/15] iio: afe: rescale: add INT_PLUS_{MICRO,NANO} support Liam Beguin
2021-12-22  3:46 ` [PATCH v11 06/15] iio: afe: rescale: add offset support Liam Beguin
2021-12-22  3:46 ` Liam Beguin [this message]
2021-12-22 12:25   ` [PATCH v11 07/15] iio: afe: rescale: use s64 for temporary scale calculations Andy Shevchenko
2021-12-22 18:21     ` Liam Beguin
2021-12-22  3:46 ` [PATCH v11 08/15] iio: afe: rescale: fix accuracy for small fractional scales Liam Beguin
2021-12-22 12:27   ` Andy Shevchenko
2021-12-22  3:46 ` [PATCH v11 09/15] iio: afe: rescale: reduce risk of integer overflow Liam Beguin
2021-12-22 12:29   ` Andy Shevchenko
2021-12-22 18:38     ` Liam Beguin
2021-12-22 18:56       ` Andy Shevchenko
2021-12-22 19:58         ` Liam Beguin
2021-12-22 21:32           ` Andy Shevchenko
2022-01-08 16:34             ` Liam Beguin
2022-01-08 17:55               ` Andy Shevchenko
2021-12-22  3:46 ` [PATCH v11 10/15] iio: afe: rescale: make use of units.h Liam Beguin
2021-12-22 12:33   ` Andy Shevchenko
2021-12-22 18:50     ` Liam Beguin
2021-12-22 18:59       ` Andy Shevchenko
2021-12-22  3:46 ` [PATCH v11 11/15] iio: test: add basic tests for the iio-rescale driver Liam Beguin
2021-12-22 12:38   ` Andy Shevchenko
2021-12-22 19:13     ` Liam Beguin
2021-12-22  3:46 ` [PATCH v11 12/15] iio: afe: rescale: add RTD temperature sensor support Liam Beguin
2021-12-22  3:46 ` [PATCH v11 13/15] iio: afe: rescale: add temperature transducers Liam Beguin
2021-12-22 12:40   ` Andy Shevchenko
2021-12-22  3:46 ` [PATCH v11 14/15] dt-bindings: iio: afe: add bindings for temperature-sense-rtd Liam Beguin
2021-12-22  3:46 ` [PATCH v11 15/15] dt-bindings: iio: afe: add bindings for temperature transducers Liam Beguin

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