leds: Provide devm_of_led_get_optional()

Add an optional variant of devm_of_led_get(). It behaves the same as
devm_of_led_get() except where the LED doesn't exist. In this case,
instead of returning -ENOENT, the function returns NULL.
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20230728153731.3742339-2-jjhiblot@traphandler.comSigned-off-by: Lee Jones <lee@kernel.org>

drivers/leds/led-class.c

@@ -402,6 +402,31 @@ void led_remove_lookup(struct led_lookup_data *led_lookup)
 }
 EXPORT_SYMBOL_GPL(led_remove_lookup);
 
+/**
+ * devm_of_led_get_optional - Resource-managed request of an optional LED device
+ * @dev:	LED consumer
+ * @index:	index of the LED to obtain in the consumer
+ *
+ * The device node of the device is parsed to find the requested LED device.
+ * The LED device returned from this function is automatically released
+ * on driver detach.
+ *
+ * @return a pointer to a LED device, ERR_PTR(errno) on failure and NULL if the
+ * led was not found.
+ */
+struct led_classdev *__must_check devm_of_led_get_optional(struct device *dev,
+							int index)
+{
+	struct led_classdev *led;
+
+	led = devm_of_led_get(dev, index);
+	if (IS_ERR(led) && PTR_ERR(led) == -ENOENT)
+		return NULL;
+
+	return led;
+}
+EXPORT_SYMBOL_GPL(devm_of_led_get_optional);
+
 static int led_classdev_next_name(const char *init_name, char *name,
 				  size_t len)
 {

include/linux/leds.h

@@ -313,6 +313,8 @@ extern struct led_classdev *of_led_get(struct device_node *np, int index);
 extern void led_put(struct led_classdev *led_cdev);
 struct led_classdev *__must_check devm_of_led_get(struct device *dev,
 						  int index);
+struct led_classdev *__must_check devm_of_led_get_optional(struct device *dev,
+						  int index);
 
 /**
  * led_blink_set - set blinking with software fallback