Re: [RFC PATCH 2/5] dt: bindings: Add multicolor class dt bindings documention

From: Dan Murphy
Date: Tue Apr 02 2019 - 07:41:07 EST


Pavel

On 4/1/19 4:29 PM, Pavel Machek wrote:
> Hi!
>
>
>> .../bindings/leds/leds-class-multicolor.txt | 140 ++++++++++++++++++
>> 1 file changed, 140 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/leds/leds-class-multicolor.txt
>>
>> diff --git a/Documentation/devicetree/bindings/leds/leds-class-multicolor.txt b/Documentation/devicetree/bindings/leds/leds-class-multicolor.txt
>> new file mode 100644
>> index 000000000000..4b1a26104c79
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/leds/leds-class-multicolor.txt
>> @@ -0,0 +1,140 @@
>> +* Multicolor LED properties
>> +
>> +Multicolor LEDs can consist of a RGB, RGBW or a RGBA LED clusters. These devices
>> +can be grouped together and also provide a modeling mechanism so that the
>> +cluster LEDs can vary in hue and intensity to produce a wide range of colors.
>> +
>> +The nodes and properties defined in this document are unique to the multicolor
>> +LED class. Common LED nodes and properties are inherited from the common.txt
>> +within this documentation directory.
>> +
>> +Required LED Child properties:
>> + - color : This is the color ID of the LED. Definitions can be found
>> + in include/linux/leds/common.txt
>> +
>> +Optional LED Child properties:
>> + - available-brightness-models : This is the phandle to the brightness-model
>> + node(s) that this LED cluster can support.
>> +
>> +Required Brightness model properties
>> + - led-brightness-model : This flag alerts the device driver and class
>> + code that this node is a brightness model node
>> + and to process the properties differently.
>> +
>> +Required Brightness model child properties
>> + - model_name : This is the name of the model presented to the user. This
>> + should be a color that the LED cluster can produce for
>> + the device it is attached to.
>> + - layout : This is the LED layout for the levels. This layout will
>> + determine the color order of the levels. The layout and
>> + level-x properties array should be the same size.
>> + - level-x : These are the values for the LEDs to produce the color that
>> + is defined. These values are placed in the array according
>> + to the layout property.
>
>> +led-controller@30 {
>> + #address-cells = <1>;
>> + #size-cells = <0>;
>> + compatible = "ti,lp5024";
>> + reg = <0x29>;
>> +
>> + lp5024_model_yellow: brightness-models {
>> + led-brightness-model;
>> + model@0 {
>> + model_name = "yellow";
>> + layout = <LED_COLOR_ID_RED
>> + LED_COLOR_ID_GREEN
>> + LED_COLOR_ID_BLUE>;
>> + level-1 = <255 227 40>;
>> + level-2 = <255 240 136>;
>> + level-3 = <255 247 196>;
>> + };
>> + };
>
> I don't think this works. RGB LED can show millions of colors. Do you
> propose to have millions of entries in dts?
> Pavel
>

I have had off line conversations with Jacek about this brightness model node.

Your concern was actually one of my concerns as well. Not only millions of entries but also having a huge
DT binary.

We wanted to RFC this to get feedback. And this is why I have not added any support for this in the framework code.

Dan

--
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Dan Murphy