linux-kernel - Re: [PATCH 2/2] leds: pwm: Add optional DT property default-brightness

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Message-ID: <e37f23e6-f471-4061-b346-4b082f37060d@salutedevices.com>
Date: Fri, 1 Nov 2024 18:42:28 +0300
From: George Stark <gnstark@...utedevices.com>
To: Lee Jones <lee@...nel.org>
CC: <pavel@....cz>, <robh@...nel.org>, <krzk+dt@...nel.org>,
	<conor+dt@...nel.org>, <linux-leds@...r.kernel.org>,
	<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<kernel@...utedevices.com>
Subject: Re: [PATCH 2/2] leds: pwm: Add optional DT property
 default-brightness

Hello Lee

Thanks for the review!

On 10/31/24 17:32, Lee Jones wrote:
> On Tue, 15 Oct 2024, George Stark wrote:
> 
>> When probing if default LED state is on then default brightness will be
>> applied instead of max brightness.
>>
>> Signed-off-by: George Stark <gnstark@...utedevices.com>
>> ---
>>   drivers/leds/leds-pwm.c | 13 ++++++++++---
>>   1 file changed, 10 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c
>> index 7961dca0db2f..514fc8ca3e80 100644
>> --- a/drivers/leds/leds-pwm.c
>> +++ b/drivers/leds/leds-pwm.c
>> @@ -65,7 +65,8 @@ static int led_pwm_set(struct led_classdev *led_cdev,
>>   
>>   __attribute__((nonnull))
>>   static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
>> -		       struct led_pwm *led, struct fwnode_handle *fwnode)
>> +		       struct led_pwm *led, struct fwnode_handle *fwnode,
>> +		       unsigned int default_brightness)
>>   {
>>   	struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
>>   	struct led_init_data init_data = { .fwnode = fwnode };
>> @@ -104,7 +105,7 @@ static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
>>   	/* set brightness */
>>   	switch (led->default_state) {
>>   	case LEDS_DEFSTATE_ON:
>> -		led_data->cdev.brightness = led->max_brightness;
>> +		led_data->cdev.brightness = default_brightness;
>>   		break;
>>   	case LEDS_DEFSTATE_KEEP:
>>   		{
>> @@ -141,6 +142,7 @@ static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
>>   static int led_pwm_create_fwnode(struct device *dev, struct led_pwm_priv *priv)
>>   {
>>   	struct led_pwm led;
>> +	unsigned int default_brightness;
>>   	int ret;
>>   
>>   	device_for_each_child_node_scoped(dev, fwnode) {
>> @@ -160,7 +162,12 @@ static int led_pwm_create_fwnode(struct device *dev, struct led_pwm_priv *priv)
>>   
>>   		led.default_state = led_init_default_state_get(fwnode);
>>   
>> -		ret = led_pwm_add(dev, priv, &led, fwnode);
>> +		ret = fwnode_property_read_u32(fwnode, "default-brightness",
>> +					       &default_brightness);
>> +		if (ret < 0 || default_brightness > led.max_brightness)
>> +			default_brightness = led.max_brightness;
>> +
>> +		ret = led_pwm_add(dev, priv, &led, fwnode, default_brightness);
> 
> This creates a lot more hopping around than is necessary.
> 
> Since led_pwm_add() already has access to the fwnode, why not look up
> the property in there instead, thus massively simplifying things.

I looked up the new property here to be near to
led_init_default_state_get (both props are from the same group) and
led_pwm_add is big enough already. And you're absolutely right that the
patch can be optimized. Please take a look at the v2

> 
> 
>>   		if (ret)
>>   			return ret;
>>   	}
>> -- 
>> 2.25.1
>>
> 

-- 
Best regards
George