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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Thu, 20 Feb 2020 11:30:43 +0100
Message-ID: <CAMuHMdWPgUKOHyspV3bL_4YKsxgXvEgQqdOzoo-8s8gi_g3rVw@mail.gmail.com>
Subject: Re: [PATCH 2/3] dt-bindings: leds: Shiji Lighting APA102C LED driver
To:     Nicolas Belin <nbelin@baylibre.com>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-leds@vger.kernel.org,
        Jacek Anaszewski <jacek.anaszewski@gmail.com>,
        Pavel Machek <pavel@ucw.cz>, Dan Murphy <dmurphy@ti.com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>, Lukas Wunner <lukas@wunner.de>
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Hi Nicolas,

CC devicetree, Lukas

On Tue, Feb 18, 2020 at 10:39 AM Nicolas Belin <nbelin@baylibre.com> wrote:
> Document Shiji Lighting APA102C LED driver device tree bindings.
>
> Signed-off-by: Nicolas Belin <nbelin@baylibre.com>
> ---
>  .../devicetree/bindings/leds/leds-apa102c.yaml     | 91 ++++++++++++++++++++++
>  1 file changed, 91 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/leds/leds-apa102c.yaml
>
> diff --git a/Documentation/devicetree/bindings/leds/leds-apa102c.yaml b/Documentation/devicetree/bindings/leds/leds-apa102c.yaml
> new file mode 100644
> index 000000000000..24bc2fc19fcb
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/leds-apa102c.yaml
> @@ -0,0 +1,91 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/leds-apa102c.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: LED driver for Shiji Lighting - APA102C
> +
> +maintainers:
> +  - Nicolas Belin <nbelin@baylibre.com>
> +
> +description:
> +  Each LED is represented as a sub-node of the leds-apa102c device.  Each LED
> +  is a three color RGB LED with 32 levels brightness adjustment that can be
> +  cascaded so that multiple LEDs can be set with a single command.
> +
> +properties:
> +  compatible:
> +    const: shiji,apa102c
> +
> +  reg:
> +    maxItems: 1
> +
> +  spi-max-frequency:
> +    maximum: 1000000
> +
> +  "#address-cells":
> +    const: 1
> +
> +  "#size-cells":
> +    const: 0
> +
> +required:
> +  - compatible
> +  - reg
> +  - spi-max-frequency
> +  - '#address-cells'
> +  - '#size-cells'
> +
> +patternProperties:
> +  "^led@[0-9]+$":
> +    type: object
> +    description: |
> +      Properties for an array of connected LEDs.
> +
> +    properties:
> +      reg:
> +        description: |
> +          This property corresponds to the led index. It has to be between 0
> +          and the number of managed leds minus 1
> +        maxItems: 1
> +
> +      label:
> +        description: |
> +          This property corresponds to the name of the led. If not set,
> +          the led index will be used to create the led name instead
> +        maxItems: 1
> +
> +      linux,default-trigger: true
> +
> +    required:
> +      - reg
> +
> +examples:
> +  - |
> +    spi {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        led-controller@0 {
> +            compatible = "shiji,apa102c";
> +            reg = <0>;
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +            spi-max-frequency = <1000000>;
> +            led@0 {
> +                reg = <0>;
> +                label = "led1";
> +            };
> +
> +            led@1 {
> +                reg = <1>;
> +                label = "led2";
> +            };
> +
> +            led@2 {
> +                reg = <2>;
> +                label = "led3";
> +            };
> +        };
> +    };

Perhaps this should use "#daisy-chained-devices" instead of listing all LEDs
explicitly?
Or would that cause problems w.r.t. LED labeling?

Documentation/devicetree/bindings/common-properties.txt

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds