FAILED: patch "[PATCH] iio: adc: ad7768-1: Fix conversion result sign" failed to apply to 6.6-stable tree

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 8236644f5ecb180e80ad92d691c22bc509b747bb
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025041758-chastity-cannot-9c43@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 8236644f5ecb180e80ad92d691c22bc509b747bb Mon Sep 17 00:00:00 2001
From: Sergiu Cuciurean <[email protected]>
Date: Thu, 6 Mar 2025 18:00:29 -0300
Subject: [PATCH] iio: adc: ad7768-1: Fix conversion result sign

The ad7768-1 ADC output code is two's complement, meaning that the voltage conversion result is a signed value.. Since the value is a 24 bit one, stored in a 32 bit variable, the sign should be extended in order to get the correct representation.

Also the channel description has been updated to signed representation, to match the ADC specifications.

index ea829c51e80b..09e7cccfd51c 100644
@@ -142,7 +142,7 @@ static const struct iio_chan_spec ad7768_channels[] = {
 		.channel = 0,
 		.scan_index = 0,
 		.scan_type = {
-			.sign = 'u',
+			.sign = 's',
 			.realbits = 24,
 			.storagebits = 32,
 			.shift = 8,

@@ -373,7 +373,7 @@ static int ad7768_read_raw(struct iio_dev *indio_dev,
 		iio_device_release_direct(indio_dev);
 		if (ret < 0)
 			return ret;
-		*val = ret;
+		*val = sign_extend32(ret, chan->scan_type.realbits - 1);
 
 		return IIO_VAL_INT;