Re: [PATCH v4] dt-bindings: leds: Add default-intensity property

[Stefan Wahren]

Hi Jonas,

Am 16.07.26 um 09:31 schrieb Jonas Rebmann:
> Hi Stefan,
>
> On 2026-07-15 18:55, Stefan Wahren wrote:
> > Am 14.07.26 um 09:35 schrieb Jonas Rebmann:
> > > +  default-intensity:
> > > +    description:
> > > +      The initial intensity of the LED color component. As the 
> > > intensity of
> > > +      each sub-LED is multiplied by the overall brightness, without 
> > > this
> > > +      property on a sub-LED, it may effectively be initialized at a 
> > > brightness
> > > +      of 0 regardless of its linux,default-trigger and 
> > > default-brightness
> > > +      properties.
> > I have some reservations about the wording. It isn't wrong, but in my
> > view, it isn't entirely clear that the initial value depends on the
> > implementation.
> >
> > Maybe something like this?
> >
> > without this property on a sub-LED, the initial intensity value depends
> > on the implementation regardless of its linux,default-trigger and
> > default-brightness properties.
>
> I wrote the sentence as a warning: You would rightfully expect that
> turning an LED on, at maximum brightness would in fact turn on the LED
> regardless of the driver. But beware: default-intensity may be needed to
> produce the expected behavior.
>
> To me, this is the important (surprising) piece of information.
I totally agree with this and this wasn't my point.
> How about:
>
> The initial intensity of the LED color component. As the intensity of
> each sub-LED is multiplied by the overall brightness, without this
> property on a sub-LED, it will be initialized at a brightness of 0
> regardless of its linux,default-trigger and default-brightness
> properties, for drivers with initial intensity values of 0.
IMO the mention of "0" suggests a driver behavior, which this generic DT 
binding can never guarantee and it confuses more than it helps.
I think in absence of default-intensity the user should consider the 
initial value as undefined. The value depend on the driver 
implementation. So I think we should avoid mention any specific values 
in this case.

Best regards
> > > +    $ref: /schemas/types.yaml#/definitions/uint32
> > > +
> > >      panic-indicator:
> > >        description:
> > >          This property specifies that the LED should be used, if at 
> > > all possible,
> > > diff --git 
> > > a/Documentation/devicetree/bindings/leds/leds-pwm-multicolor.yaml 
> > > b/Documentation/devicetree/bindings/leds/leds-pwm-multicolor.yaml
> > > index a31a202afe5c..08e28c5f08a8 100644
> > > --- a/Documentation/devicetree/bindings/leds/leds-pwm-multicolor.yaml
> > > +++ b/Documentation/devicetree/bindings/leds/leds-pwm-multicolor.yaml
> > > @@ -45,6 +45,9 @@ properties:
> > >                 color: true
> > >    +          default-intensity:
> > > +            default: 0
> > > +