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

Jean-Jacques Hiblot
2019-07-02T11:11:58Z

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@ti.com>
>>
>> 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@ti.com>
>> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
>> Cc: devicetree@vger.kernel.org
>> ---
>> .../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
>>