[PATCH v2] gpiolib: normalize the return value of gc->get() on behalf of buggy drivers

[Bartosz Golaszewski]

Commit 86ef402d805d ("gpiolib: sanitize the return value of
gpio_chip::get()") started checking the return value of the .get()
callback in struct gpio_chip. Now - almost a year later - it turns out
that there are quite a few drivers in tree that can break with this
change. Partially revert it: normalize the return value in GPIO core but
also emit a warning.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 86ef402d805d ("gpiolib: sanitize the return value of gpio_chip::get()")
Reported-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Closes: https://lore.kernel.org/all/aZSkqGTqMp_57qC7@xxxxxxxxxx/
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
---
Changes in v2:
- it's gpio_chip::get() that needs normalizing, not gpio_chip::set()
- Link to v1: https://patch.msgid.link/20260219-gpiolib-set-normalize-v1-1-f0d53a009db4@xxxxxxxxxxxxxxxx
---
 drivers/gpio/gpiolib.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index c52200eaaaff82b12f22dd1ee8459bdd8ec10d81..c9cd751e7de2307fc5994eb682c53f2b3ce39233 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -3268,8 +3268,12 @@ static int gpiochip_get(struct gpio_chip *gc, unsigned int offset)
 
 	/* Make sure this is called after checking for gc->get(). */
 	ret = gc->get(gc, offset);
-	if (ret > 1)
-		ret = -EBADE;
+	if (ret > 1) {
+		gpiochip_warn(gc,
+			"invalid return value from gc->get(): %d, consider fixing the driver\n",
+			ret);
+		ret = !!ret;
+	}
 
 	return ret;
 }

---
base-commit: 50f68cc7be0a2cbf54d8f6aaf17df32fb01acc3f
change-id: 20260219-gpiolib-set-normalize-1080e2eda113

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>