patch "iio: inkern: apply consumer scale when no channel scale is available" added to char-misc-next

patch "iio: inkern: apply consumer scale when no channel scale is available" added to char-misc-next

[gregkh]

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

    iio: inkern: apply consumer scale when no channel scale is available

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-next 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 also be merged in the next major kernel release
during the merge window.

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


From 14b457fdde38de594a4bc4bd9075019319d978da Mon Sep 17 00:00:00 2001
From: Liam Beguin <liambeguin@gmail.com>
Date: Sat, 8 Jan 2022 15:53:05 -0500
Subject: iio: inkern: apply consumer scale when no channel scale is available

When a consumer calls iio_read_channel_processed() and no channel scale
is available, it's assumed that the scale is one and the raw value is
returned as expected.

On the other hand, if the consumer calls iio_convert_raw_to_processed()
the scaling factor requested by the consumer is not applied.

This for example causes the consumer to process mV when expecting uV.
Make sure to always apply the scaling factor requested by the consumer.

Fixes: adc8ec5ff183 ("iio: inkern: pass through raw values if no scaling")
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/20220108205319.2046348-3-liambeguin@gmail.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/iio/inkern.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index 021e1397ffc5..dbe13fad3cbb 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -607,10 +607,10 @@ static int iio_convert_raw_to_processed_unlocked(struct iio_channel *chan,
 					IIO_CHAN_INFO_SCALE);
 	if (scale_type < 0) {
 		/*
-		 * Just pass raw values as processed if no scaling is
-		 * available.
+		 * If no channel scaling is available apply consumer scale to
+		 * raw value and return.
 		 */
-		*processed = raw;
+		*processed = raw * scale;
 		return 0;
 	}
 
-- 
2.35.1