Re: [PATCH v9 4/5] dt-bindings: backlight: Add led-backlight binding

[Jean-Jacques Hiblot]

Rob,

On 08/10/2019 14:51, Jean-Jacques Hiblot wrote:
> Hi Rob,
>
> On 07/10/2019 18:15, Rob Herring wrote:
> > Please send DT bindings to DT list or it's never in my queue. IOW,
> > send patches to the lists that get_maintainers.pl tells you to.
> >
> > On Mon, Oct 7, 2019 at 7:45 AM Jean-Jacques Hiblot <jjhiblot@xxxxxx> 
> > wrote:
> > > Add DT binding for led-backlight.
> > >
> > > Signed-off-by: Jean-Jacques Hiblot <jjhiblot@xxxxxx>
> > > Reviewed-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
> > > Reviewed-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
> > > ---
> > > Â .../bindings/leds/backlight/led-backlight.txt | 28 
> > > +++++++++++++++++++
> > > Â 1 file changed, 28 insertions(+)
> > > Â create mode 100644 
> > > Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
> > Please make this a DT schema.
>
> OK.
>
> BTW I used "make dt_binding_check" but had to fix a couple of YAMLs 
> file to get it to work. Do you have a kernel tree with already all the 
> YAML files in good shape ? Or do you want me to post the changes to 
> devicetree@xxxxxxxxxxxxxxx ?
>
>
> > > diff --git 
> > > a/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt 
> > > b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
> > > new file mode 100644
> > > index 000000000000..4c7dfbe7f67a
> > > --- /dev/null
> > > +++ 
> > > b/Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
> > > @@ -0,0 +1,28 @@
> > > +led-backlight bindings
> > > +
> > > +This binding is used to describe a basic backlight device made of 
> > > LEDs.
> > > +It can also be used to describe a backlight device controlled by 
> > > the output of
> > > +a LED driver.
> > > +
> > > +Required properties:
> > > +Â - compatible: "led-backlight"
> > > +Â - leds: a list of LEDs
> > 'leds' is already used as a node name and mixing is not ideal.
> >
> > We already have 'flash-leds' in use and with the same definition, so
> > lets continue that and use 'backlight-leds'.
> OK

I am taking that back. I have added of_get_led() and devm_of_get_led() 
to the LED core to make it easier to get a LED from the DT. I modeled 
the interface like it is done for PWM, PHYs or clocks. The property 
containing list/array of phandle is always named the same. To get one 
particular PWM/PHY/clock, a identifier (name or integer) must be provided.

So unless there is a strong incentive to do otherwise I's rather keep 
this name here.


JJ


> > > +
> > > +Optional properties:
> > > +Â - brightness-levels: Array of distinct brightness levels. The 
> > > levels must be
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ in the range accepted by the underlying LED 
> > > devices.
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ This is used to translate a backlight 
> > > brightness level
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ into a LED brightness level. If it is not 
> > > provided, the
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ identity mapping is used.
> > > +
> > > +Â - default-brightness-level: The default brightness level.
> > You can just assume these 2 get a common schema at some point. So just
> > need to define any additional constraints if possible.
>
> Maybe we should keep them until such a common schema is written ?
>
> JJ
>
> > Rob