patch "iio: pressure: bmp280: Fix BMP580 temperature reading" added to char-misc-linus

patch "iio: pressure: bmp280: Fix BMP580 temperature reading" added to char-misc-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    iio: pressure: bmp280: Fix BMP580 temperature reading

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-linus 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 hopefully also be merged in Linus's tree for the
next -rc kernel release.

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


From 0f0f6306617cb4b6231fc9d4ec68ab9a56dba7c0 Mon Sep 17 00:00:00 2001
From: Adam Rizkalla <ajarizzo@gmail.com>
Date: Thu, 25 Apr 2024 01:22:49 -0500
Subject: iio: pressure: bmp280: Fix BMP580 temperature reading

Fix overflow issue when storing BMP580 temperature reading and
properly preserve sign of 24-bit data.

Signed-off-by: Adam Rizkalla <ajarizzo@gmail.com>
Tested-By: Vasileios Amoiridis <vassilisamir@gmail.com>
Acked-by: Angel Iglesias <ang.iglesiasg@gmail.com>
Link: https://lore.kernel.org/r/Zin2udkXRD0+GrML@adam-asahi.lan
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/iio/pressure/bmp280-core.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
index 09f53d987c7d..221fa2c552ae 100644
--- a/drivers/iio/pressure/bmp280-core.c
+++ b/drivers/iio/pressure/bmp280-core.c
@@ -1394,12 +1394,12 @@ static int bmp580_read_temp(struct bmp280_data *data, int *val, int *val2)
 
 	/*
 	 * Temperature is returned in Celsius degrees in fractional
-	 * form down 2^16. We rescale by x1000 to return milli Celsius
-	 * to respect IIO ABI.
+	 * form down 2^16. We rescale by x1000 to return millidegrees
+	 * Celsius to respect IIO ABI.
 	 */
-	*val = raw_temp * 1000;
-	*val2 = 16;
-	return IIO_VAL_FRACTIONAL_LOG2;
+	raw_temp = sign_extend32(raw_temp, 23);
+	*val = ((s64)raw_temp * 1000) / (1 << 16);
+	return IIO_VAL_INT;
 }
 
 static int bmp580_read_press(struct bmp280_data *data, int *val, int *val2)
-- 
2.45.2