linux-kernel - Re: [PATCH v5 3/4] leds: led-class: Add devicetree support to led

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Message-ID: <b875f811-6371-4ff4-9cc2-a0a2c82a569c@kernel.org>
Date: Thu, 11 Sep 2025 11:01:00 +0200
From: Hans de Goede <hansg@...nel.org>
To: Lee Jones <lee@...nel.org>, Aleksandrs Vinarskis <alex@...arskis.com>
Cc: 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>,
 Jingoo Han <jingoohan1@...il.com>, Mauro Carvalho Chehab
 <mchehab@...nel.org>, Jean-Jacques Hiblot <jjhiblot@...phandler.com>,
 Jacopo Mondi <jacopo@...ndi.org>, Sakari Ailus
 <sakari.ailus@...ux.intel.com>, Bjorn Andersson <andersson@...nel.org>,
 Konrad Dybcio <konradybcio@...nel.org>, Daniel Thompson
 <danielt@...nel.org>, linux-leds@...r.kernel.org,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 dri-devel@...ts.freedesktop.org, linux-media@...r.kernel.org,
 linux-arm-msm@...r.kernel.org, threeway@...il.com,
 Andy Shevchenko <andy.shevchenko@...il.com>,
 Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH v5 3/4] leds: led-class: Add devicetree support to
 led_get()

Hi Lee,

On 11-Sep-25 10:15 AM, Lee Jones wrote:
> On Wed, 10 Sep 2025, Aleksandrs Vinarskis wrote:
> 
>> From: Hans de Goede <hansg@...nel.org>
>>
>> Add 'name' argument to of_led_get() such that it can lookup LEDs in
>> devicetree by either name or index.
>>
>> And use this modified function 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>
> 
> Remind me why this can't go in through LED again?

I don't think anyone has discussed how to merge this yet.

I believe that the LED tree is the correct tree to merge this
entire series through, once the DT bits have been reviewed.

Regards,

Hans




>> Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
>> Signed-off-by: Hans de Goede <hansg@...nel.org>
>> Signed-off-by: Aleksandrs Vinarskis <alex@...arskis.com>
>> ---
>>  drivers/leds/led-class.c | 17 +++++++++++++++--
>>  1 file changed, 15 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
>> index 15633fbf3c166aa4f521774d245f6399a642bced..f3faf37f9a08ac762ed87b91cb3cab5faa8eacb0 100644
>> --- a/drivers/leds/led-class.c
>> +++ b/drivers/leds/led-class.c
>> @@ -252,15 +252,23 @@ static const struct class leds_class = {
>>   * 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
>> + * @name: the name of the LED used to map it to its function, if present
>>   *
>>   * 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);
>> @@ -324,7 +332,7 @@ struct led_classdev *__must_check devm_of_led_get(struct device *dev,
>>  	if (!dev)
>>  		return ERR_PTR(-EINVAL);
>>  
>> -	led = of_led_get(dev->of_node, index);
>> +	led = of_led_get(dev->of_node, index, NULL);
>>  	if (IS_ERR(led))
>>  		return led;
>>  
>> @@ -342,9 +350,14 @@ 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;
>>  
>> +	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
>>
>>
>