linux-kernel - [PATCH 2/2] leds: led-class: Add devicetree support to led

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Message-ID: <010201990a1f6559-9e836a40-f534-4535-bd59-5e967d80559a-000000@eu-west-1.amazonses.com>
Date: Tue, 2 Sep 2025 11:10:53 +0000
From: Aleksandrs Vinarskis <alex@...arskis.com>
To: Hans de Goede <hansg@...nel.org>, Lee Jones <lee@...nel.org>, 
	Pavel Machek <pavel@...nel.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, 
	Conor Dooley <conor+dt@...nel.org>, 
	Bryan O'Donoghue <bryan.odonoghue@...aro.org>
Cc: linux-leds@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, 
	Aleksandrs Vinarskis <alex@...arskis.com>, 
	Andy Shevchenko <andy.shevchenko@...il.com>, 
	Linus Walleij <linus.walleij@...aro.org>, 
	Hans de Goede <hansg@...nel.org>
Subject: [PATCH 2/2] leds: led-class: Add devicetree support to led_get()

From: Hans de Goede <hansg@...nel.org>

Turn of_led_get() into a more generic __of_led_get() helper function,
which can lookup LEDs in devicetree by either name or index.

And use this new helper to add devicetree support to the generic
(non devicetree specific) [devm_]led_get() function.

This uses the standard devicetree pattern of adding a -names string array
to map names to the indexes for an array of resources.

Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
Reviewed-by: Lee Jones <lee@...nel.org>
Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Hans de Goede <hdegoede@...hat.com>
Tested-by: Aleksandrs Vinarskis <alex@...arskis.com>
---
 drivers/leds/led-class.c | 38 +++++++++++++++++++++++++++++---------
 1 file changed, 29 insertions(+), 9 deletions(-)

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 15633fbf3c166aa4f521774d245f6399a642bced..6f2ef4fa556b44ed3bf69dff556ae16fd2b7652b 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -248,19 +248,18 @@ static const struct class leds_class = {
 	.pm = &leds_class_dev_pm_ops,
 };
 
-/**
- * of_led_get() - request a LED device via the LED framework
- * @np: device node to get the LED device from
- * @index: the index of the LED
- *
- * Returns the LED device parsed from the phandle specified in the "leds"
- * property of a device tree node or a negative error-code on failure.
- */
-static struct led_classdev *of_led_get(struct device_node *np, int index)
+static struct led_classdev *__of_led_get(struct device_node *np, int index,
+					 const char *name)
 {
 	struct device *led_dev;
 	struct device_node *led_node;
 
+	/*
+	 * For named LEDs, first look up the name in the "led-names" property.
+	 * If it cannot be found, then of_parse_phandle() will propagate the error.
+	 */
+	if (name)
+		index = of_property_match_string(np, "led-names", name);
 	led_node = of_parse_phandle(np, "leds", index);
 	if (!led_node)
 		return ERR_PTR(-ENOENT);
@@ -271,6 +270,20 @@ static struct led_classdev *of_led_get(struct device_node *np, int index)
 	return led_module_get(led_dev);
 }
 
+/**
+ * of_led_get() - request a LED device via the LED framework
+ * @np: device node to get the LED device from
+ * @index: the index of the LED
+ *
+ * Returns the LED device parsed from the phandle specified in the "leds"
+ * property of a device tree node or a negative error-code on failure.
+ */
+struct led_classdev *of_led_get(struct device_node *np, int index)
+{
+	return __of_led_get(np, index, NULL);
+}
+EXPORT_SYMBOL_GPL(of_led_get);
+
 /**
  * led_put() - release a LED device
  * @led_cdev: LED device
@@ -342,9 +355,16 @@ EXPORT_SYMBOL_GPL(devm_of_led_get);
 struct led_classdev *led_get(struct device *dev, char *con_id)
 {
 	struct led_lookup_data *lookup;
+	struct led_classdev *led_cdev;
 	const char *provider = NULL;
 	struct device *led_dev;
 
+	if (dev->of_node) {
+		led_cdev = __of_led_get(dev->of_node, -1, con_id);
+		if (!IS_ERR(led_cdev) || PTR_ERR(led_cdev) != -ENOENT)
+			return led_cdev;
+	}
+
 	mutex_lock(&leds_lookup_lock);
 	list_for_each_entry(lookup, &leds_lookup_list, list) {
 		if (!strcmp(lookup->dev_id, dev_name(dev)) &&

-- 
2.48.1