Re: Combining multiple PWM LEDs into RGB LED?

[Jacek Anaszewski <jacek.anaszewski@gmail.com>]

Hi Sven,

On 1/20/22 3:07 PM, Sven Schwermer wrote:
> Hi,
> 
> I'm wondering about the correct device tree syntax for organizing 
> multiple PWM LEDs into a multi-color (RGB) LED. This is my device tree:
> 
> / {
>    rgb-led {
>      pinctrl-names = "default";Hi Sven,
>      pinctrl-0 = <&pinctrl_leds>;
>      compatible = "pwm-leds";
>      multi-led@0 {
>        color = <LED_COLOR_ID_RGB>;
>        led-red {
>          pwms = <&pwm1 0 1000000>;
>          color = <LED_COLOR_ID_RED>;
>          max-brightness = <65535>;
>        };
>        led-green {
>          pwms = <&pwm2 0 1000000>;
>          color = <LED_COLOR_ID_GREEN>;
>          max-brightness = <65535>;
>        };
>        led-blue {
>          pwms = <&pwm3 0 1000000>;
>          color = <LED_COLOR_ID_BLUE>;
>          max-brightness = <65535>;
>        };
>      };
>    };
>    /* ... */
> };
> 
> My kernel complains as follows:
> 
> of_pwm_get(): can't parse "pwms" property
> leds_pwm rgb-led: unable to request PWM for multi-led: -2
> leds_pwm: probe of rgb-led failed with error -2
> 
> Is my syntax incorrect or is this not a use case that is currently 
> supported? I should also note that I back-ported the multi-LED feature 
> to 5.4.158 so I may have missed some relevant patches.
> 
> Any insight is appreciated.

leds-pwm driver doesn't have support for multicolor LEDs. You'd have to
write a new driver, say leds-pwm-multicolor.

-- 
Best regards,
Jacek Anaszewski