Re: [PATCH 4/4] devicetree: Add led-backlight binding

[Jean-Jacques Hiblot]

Daniel,

On 02/07/2019 11:58, Daniel Thompson wrote:
> On Mon, Jul 01, 2019 at 05:14:23PM +0200, Jean-Jacques Hiblot wrote:
> > From: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> >
> > Add DT binding for led-backlight.
> I think the patchset is in the wrong order; the DT bindings
> documentation should appear *before* the binding is
> implemented (amoung other things this prevent transient checkpatch
> warnings as the patchset is applied).
ok
> > Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> > Signed-off-by: Jean-Jacques Hiblot <jjhiblot@xxxxxx>
> > Cc: devicetree@xxxxxxxxxxxxxxx
> > ---
> >   .../video/backlight/led-backlight.txt         | 39 +++++++++++++++++++
> >   1 file changed, 39 insertions(+)
> >   create mode 100644 Documentation/devicetree/bindings/video/backlight/led-backlight.txt
> >
> > diff --git a/Documentation/devicetree/bindings/video/backlight/led-backlight.txt b/Documentation/devicetree/bindings/video/backlight/led-backlight.txt
> > new file mode 100644
> > index 000000000000..216cd52d624a
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/video/backlight/led-backlight.txt
> > @@ -0,0 +1,39 @@
> > +led-backlight bindings
> > +
> > +The node of the backlight driver IS the node of the LED.
> > +
> > +Required properties:
> > +  - compatible: "led-backlight"
> > +  - brightness-levels: Array of distinct LED brightness levels. These
> > +      are in the range from 0 to 255, passed to the LED class driver.
> > +  - default-brightness-level: the default brightness level (index into the
> > +      array defined by the "brightness-levels" property)
> I think brightness-levels and default-brightness-level could be
> optional properties since a default 1:1 mapping seems reasonable given
> how constrained the LED brightness values are.

That is probably a good idea. Expect it in v2

Thanks,

JJ

> Daniel.
>
>
> > +
> > +Optional properties:
> > +  - power-supply: regulator for supply voltage
> > +  - enable-gpios: contains a single GPIO specifier for the GPIO which enables
> > +                  and disables the backlight (see GPIO binding[0])
> > +
> > +[0]: Documentation/devicetree/bindings/gpio/gpio.txt
> > +
> > +Example:
> > +
> > +led_ctrl {
> > +	red_led@1 {
> > +	        label = "red";
> > +		reg = <1>;
> > +	}
> > +
> > +	backlight_led@2 {
> > +		function = LED_FUNCTION_BACKLIGHT;
> > +		reg = <2>;
> > +
> > +		compatible = "led-backlight";
> > +
> > +		brightness-levels = <0 4 8 16 32 64 128 255>;
> > +		default-brightness-level = <6>;
> > +
> > +		power-supply = <&vdd_bl_reg>;
> > +		enable-gpios = <&gpio 58 0>;
> > +	};
> > +};
> > --
> > 2.17.1