Subject: patch "iio: afe: rescale: use s64 for temporary scale calculations" added to char-misc-testing
To:     liambeguin@gmail.com, Jonathan.Cameron@huawei.com,
        Stable@vger.kernel.org, andy.shevchenko@gmail.com, peda@axentia.se
From:   <gregkh@linuxfoundation.org>
Date:   Fri, 18 Mar 2022 12:42:33 +0100
Message-ID: <164760375375146@kroah.com>
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This is a note to let you know that I've just added the patch titled

    iio: afe: rescale: use s64 for temporary scale calculations

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-testing branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will be merged to the char-misc-next branch sometime soon,
after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.


From 51593106b608ae4247cc8da928813347da16d025 Mon Sep 17 00:00:00 2001
From: Liam Beguin <liambeguin@gmail.com>
Date: Sat, 8 Jan 2022 15:53:07 -0500
Subject: iio: afe: rescale: use s64 for temporary scale calculations

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.

Fixes: 8b74816b5a9a ("iio: afe: rescale: new driver")
Signed-off-by: Liam Beguin <liambeguin@gmail.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220108205319.2046348-5-liambeguin@gmail.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.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 774eb3044edd..271d73e420c4 100644
--- a/drivers/iio/afe/iio-rescale.c
+++ b/drivers/iio/afe/iio-rescale.c
@@ -39,7 +39,7 @@ static int rescale_read_raw(struct iio_dev *indio_dev,
 			    int *val, int *val2, long mask)
 {
 	struct rescale *rescale = iio_priv(indio_dev);
-	unsigned long long tmp;
+	s64 tmp;
 	int ret;
 
 	switch (mask) {
@@ -77,10 +77,10 @@ static int rescale_read_raw(struct iio_dev *indio_dev,
 			*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 ret;
 		default:
-- 
2.35.1