gpiolib: make value setters have return values

Change the in-kernel consumer interface for GPIOs: make all variants of
value setters that don't have a return value, return a signed integer
instead. That will allow these routines to indicate failures to callers.

This doesn't change the implementation just yet, we'll do it in
subsequent commits.

We need to update the gpio-latch module as it passes the address of
value setters as a function pointer argument and thus cares about its
type.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20250220-gpio-set-retval-v2-2-bc4cfd38dae3@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

1 files changed, 30 insertions, 23 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e8678a6c82ea..f659437710c1 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -3497,13 +3497,13 @@ EXPORT_SYMBOL_GPL(gpiod_get_array_value);
  * @desc: gpio descriptor whose state need to be set.
  * @value: Non-zero for setting it HIGH otherwise it will set to LOW.
  */
-static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value)
+static int gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value)
 {
 	int ret = 0, offset = gpio_chip_hwgpio(desc);
 
 	CLASS(gpio_chip_guard, guard)(desc);
 	if (!guard.gc)
-		return;
+		return -ENODEV;
 
 	if (value) {
 		ret = gpiochip_direction_input(guard.gc, offset);
@@ -3517,6 +3517,8 @@ static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value)
 		gpiod_err(desc,
 			  "%s: Error in set_value for open drain err %d\n",
 			  __func__, ret);
+
+	return ret;
 }
 
 /*
@@ -3524,13 +3526,13 @@ static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value)
  * @desc: gpio descriptor whose state need to be set.
  * @value: Non-zero for setting it HIGH otherwise it will set to LOW.
  */
-static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value)
+static int gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value)
 {
 	int ret = 0, offset = gpio_chip_hwgpio(desc);
 
 	CLASS(gpio_chip_guard, guard)(desc);
 	if (!guard.gc)
-		return;
+		return -ENODEV;
 
 	if (value) {
 		ret = gpiochip_direction_output(guard.gc, offset, 1);
@@ -3544,16 +3546,20 @@ static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value
 		gpiod_err(desc,
 			  "%s: Error in set_value for open source err %d\n",
 			  __func__, ret);
+
+	return ret;
 }
 
-static void gpiod_set_raw_value_commit(struct gpio_desc *desc, bool value)
+static int gpiod_set_raw_value_commit(struct gpio_desc *desc, bool value)
 {
 	CLASS(gpio_chip_guard, guard)(desc);
 	if (!guard.gc)
-		return;
+		return -ENODEV;
 
 	trace_gpio_value(desc_to_gpio(desc), 0, value);
 	guard.gc->set(guard.gc, gpio_chip_hwgpio(desc), value);
+
+	return 0;
 }
 
 /*
@@ -3711,12 +3717,12 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep,
  * This function can be called from contexts where we cannot sleep, and will
  * complain if the GPIO chip functions potentially sleep.
  */
-void gpiod_set_raw_value(struct gpio_desc *desc, int value)
+int gpiod_set_raw_value(struct gpio_desc *desc, int value)
 {
-	VALIDATE_DESC_VOID(desc);
+	VALIDATE_DESC(desc);
 	/* Should be using gpiod_set_raw_value_cansleep() */
 	WARN_ON(desc->gdev->can_sleep);
-	gpiod_set_raw_value_commit(desc, value);
+	return gpiod_set_raw_value_commit(desc, value);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
 
@@ -3729,16 +3735,17 @@ EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
  * different semantic quirks like active low and open drain/source
  * handling.
  */
-static void gpiod_set_value_nocheck(struct gpio_desc *desc, int value)
+static int gpiod_set_value_nocheck(struct gpio_desc *desc, int value)
 {
 	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
 		value = !value;
+
 	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
-		gpio_set_open_drain_value_commit(desc, value);
+		return gpio_set_open_drain_value_commit(desc, value);
 	else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
-		gpio_set_open_source_value_commit(desc, value);
-	else
-		gpiod_set_raw_value_commit(desc, value);
+		return gpio_set_open_source_value_commit(desc, value);
+
+	return gpiod_set_raw_value_commit(desc, value);
 }
 
 /**
@@ -3752,12 +3759,12 @@ static void gpiod_set_value_nocheck(struct gpio_desc *desc, int value)
  * This function can be called from contexts where we cannot sleep, and will
  * complain if the GPIO chip functions potentially sleep.
  */
-void gpiod_set_value(struct gpio_desc *desc, int value)
+int gpiod_set_value(struct gpio_desc *desc, int value)
 {
-	VALIDATE_DESC_VOID(desc);
+	VALIDATE_DESC(desc);
 	/* Should be using gpiod_set_value_cansleep() */
 	WARN_ON(desc->gdev->can_sleep);
-	gpiod_set_value_nocheck(desc, value);
+	return gpiod_set_value_nocheck(desc, value);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_value);
 
@@ -4176,11 +4183,11 @@ EXPORT_SYMBOL_GPL(gpiod_get_array_value_cansleep);
  *
  * This function is to be called from contexts that can sleep.
  */
-void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)
+int gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)
 {
 	might_sleep();
-	VALIDATE_DESC_VOID(desc);
-	gpiod_set_raw_value_commit(desc, value);
+	VALIDATE_DESC(desc);
+	return gpiod_set_raw_value_commit(desc, value);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);
 
@@ -4194,11 +4201,11 @@ EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);
  *
  * This function is to be called from contexts that can sleep.
  */
-void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
+int gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
 {
 	might_sleep();
-	VALIDATE_DESC_VOID(desc);
-	gpiod_set_value_nocheck(desc, value);
+	VALIDATE_DESC(desc);
+	return gpiod_set_value_nocheck(desc, value);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep);