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From: Liam Beguin <liambeguin@gmail.com>
To: liambeguin@gmail.com, peda@axentia.se, jic23@kernel.org, lars@metafoo.de
Cc: linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org,
	devicetree@vger.kernel.org, robh+dt@kernel.org
Subject: [PATCH v10 07/14] iio: afe: rescale: use s64 for temporary scale calculations
Date: Sun, 19 Dec 2021 17:39:46 -0500	[thread overview]
Message-ID: <20211219223953.16074-8-liambeguin@gmail.com> (raw)
In-Reply-To: <20211219223953.16074-1-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>
---
 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 e88b63747a46..e3680998565e 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:[~2021-12-19 22:40 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-19 22:39 [PATCH v10 00/14] iio: afe: add temperature rescaling support Liam Beguin
2021-12-19 22:39 ` [PATCH v10 01/14] iio: inkern: apply consumer scale on IIO_VAL_INT cases Liam Beguin
2021-12-19 22:39 ` [PATCH v10 02/14] iio: inkern: apply consumer scale when no channel scale is available Liam Beguin
2021-12-19 22:39 ` [PATCH v10 03/14] iio: inkern: make a best effort on offset calculation Liam Beguin
2021-12-21  5:42   ` Andy Shevchenko
2021-12-21 17:50     ` Liam Beguin
2021-12-19 22:39 ` [PATCH v10 04/14] iio: afe: rescale: expose scale processing function Liam Beguin
     [not found]   ` <CAHp75VdfPf6FMvkGqhhQg5e5XE1cgE-K8seobe5n0yGarnPGtQ@mail.gmail.com>
2021-12-21  5:43     ` Andy Shevchenko
2021-12-22  2:28       ` Liam Beguin
2021-12-19 22:39 ` [PATCH v10 05/14] iio: afe: rescale: add INT_PLUS_{MICRO,NANO} support Liam Beguin
2021-12-19 22:39 ` [PATCH v10 06/14] iio: afe: rescale: add offset support Liam Beguin
2021-12-19 22:39 ` Liam Beguin [this message]
2021-12-19 22:39 ` [PATCH v10 08/14] iio: afe: rescale: fix accuracy for small fractional scales Liam Beguin
2021-12-19 22:39 ` [PATCH v10 09/14] iio: afe: rescale: reduce risk of integer overflow Liam Beguin
2021-12-19 22:39 ` [PATCH v10 10/14] iio: test: add basic tests for the iio-rescale driver Liam Beguin
2021-12-21  7:09   ` kernel test robot
2021-12-21  8:03   ` kernel test robot
2021-12-19 22:39 ` [PATCH v10 11/14] iio: afe: rescale: add RTD temperature sensor support Liam Beguin
2021-12-19 22:39 ` [PATCH v10 12/14] iio: afe: rescale: add temperature transducers Liam Beguin
2021-12-19 22:39 ` [PATCH v10 13/14] dt-bindings: iio: afe: add bindings for temperature-sense-rtd Liam Beguin
2021-12-19 22:39 ` [PATCH v10 14/14] dt-bindings: iio: afe: add bindings for temperature transducers Liam Beguin
2021-12-20 21:37 ` [PATCH v10 00/14] iio: afe: add temperature rescaling support Peter Rosin
2021-12-22  3:29   ` Liam Beguin

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