Re: [PATCH v2] leds: gpio: Set max brightness to 1

From: Pavel Machek
Date: Tue Dec 29 2020 - 11:05:50 EST


Hi!

> GPIO LEDs only know 2 states: ON or OFF and do not have PWM capabilities.
> However, the max brightness is reported as 255.
>
> This patch sets the max brightness value of a GPIO controlled LED to 1.
>
> Tested on my PinePhone 1.2.
>
> Signed-off-by: Dylan Van Assche <me@xxxxxxxxxxxxxxxxx>
> ---
> v2 drops an obsolete change in include/linux/leds.h

I thought that one looked odd.

> +++ b/drivers/leds/leds-gpio.c
> @@ -96,7 +96,8 @@ static int create_gpio_led(const struct gpio_led *template,
> } else {
> state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
> }
> - led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
> + led_dat->cdev.brightness = state ? LED_ON : LED_OFF;
> + led_dat->cdev.max_brightness = LED_ON;

Would simpler version work:

> + led_dat->cdev.brightness = state;
> + led_dat->cdev.max_brightness = 1;

? Easier to understand... I'd prefer that version unless it causes
warnings or something.

Pavel
--
http://www.livejournal.com/~pavelmachek

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