linux-kernel - Re: [PATCH 3/4] dt-bindings: leds: Add binding for a multicolor group of LEDs

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Message-ID: <c84d0513-b89b-0eea-eeaf-68dc634bd7b0@traphandler.com>
Date:   Fri, 1 Jul 2022 11:33:22 +0200
From:   Jean-Jacques Hiblot <jjhiblot@...phandler.com>
To:     Rob Herring <robh@...nel.org>
CC:     <pavel@....cz>, <sven.schwermer@...ruptive-technologies.com>,
        <krzysztof.kozlowski+dt@...aro.org>, <johan+linaro@...nel.org>,
        <marijn.suijten@...ainline.org>, <bjorn.andersson@...aro.org>,
        <andy.shevchenko@...il.com>, <linux-leds@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/4] dt-bindings: leds: Add binding for a multicolor group
 of LEDs


On 28/06/2022 00:12, Rob Herring wrote:
> On Wed, Jun 15, 2022 at 05:49:17PM +0200, Jean-Jacques Hiblot wrote:
>> This allows to group multiple monochromatic LEDs into a multicolor
>> LED, e.g. RGB LEDs.
>>
>> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@...phandler.com>
>> ---
>>   .../bindings/leds/leds-group-multicolor.yaml  | 94 +++++++++++++++++++
>>   1 file changed, 94 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/leds/leds-group-multicolor.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/leds/leds-group-multicolor.yaml b/Documentation/devicetree/bindings/leds/leds-group-multicolor.yaml
>> new file mode 100644
>> index 000000000000..30a67985ae33
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/leds/leds-group-multicolor.yaml
>> @@ -0,0 +1,94 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/leds/leds-group-multicolor.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Multi-color LED built with monochromatic LEDs
>> +
>> +maintainers:
>> +  - Jean-Jacques Hiblot <jjhiblot@...phandler.com>
>> +
>> +description: |
>> +  This driver combines several monochromatic LEDs into one multi-color
>> +  LED using the multicolor LED class.
>> +
>> +properties:
>> +  compatible:
>> +    const: leds-group-multicolor
>> +
>> +  multi-led:
>> +    type: object
>> +
>> +    patternProperties:
>> +      "^led-[0-9a-z]+$":
>> +        type: object
>> +        $ref: common.yaml#
>> +
>> +        additionalProperties: false
>> +
>> +        properties:
>> +          leds:
> Not a standard property. What is the type?
That would be a reference to the node of a LED
> Really, just do a GPIO multi-color LED binding similar to the PWM one
> rather than adding this layer. I suppose you could combine LEDs from all
> different controllers, but that seems somewhat unlikely to me.

I'm not using gpio leds, rather leds driven by two TLC5925.

I agree that combining from different model of controller is unlikely. 
However from 2 separate chips of the same model is not (ex: driving 5 
RGB LEDs with two 8-output chips)

In the case of the TLC5925, that is not really a problem because as long 
as the chips are on the same CS, they are considered as a single entity 
by the driver. But for I2C chips at least that would be a problem.


JJ

>
> Rob