Subject: Re: [RFC 06/25] dt-bindings: leds: Add Titan Micro Electronics TM1628

From: Rob Herring <[email-masked]>
Date: Thu, 19 Dec 2019 17:04:20 -0600

On Thu, Dec 12, 2019 at 04:39:33AM +0100, Andreas Färber wrote:
> Add a YAML schema binding for TM1628 LED controller.
> 
> Cc: [email-masked]
> Signed-off-by: Andreas Färber <[email-masked]>
> ---
>  @Rob: How could we express constraints on two-cell reg value ranges here?

It's encoded as a matrix, so something like this:

reg:
  items:
    items:
      - # constraints on 1st cell value
      - # constraints on 2nd cell value

>        Should we also model constraints on reg range by #grids property?

So the value of #grid defines the max values in reg? Unfortunately, 
we can't yet for json-schema. There's been some proposals, but nothing 
final I think.

>  .../devicetree/bindings/leds/titanmec,tm1628.yaml  | 80 ++++++++++++++++++++++
>  1 file changed, 80 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/leds/titanmec,tm1628.yaml
> 
> diff --git a/Documentation/devicetree/bindings/leds/titanmec,tm1628.yaml b/Documentation/devicetree/bindings/leds/titanmec,tm1628.yaml
> new file mode 100644
> index 000000000000..024875656e79
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/titanmec,tm1628.yaml
> @@ -0,0 +1,80 @@
> +# SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/titanmec,tm1628.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Titan Micro Electronics TM1628 LED controller
> +
> +maintainers:
> +  - Andreas Färber <[email-masked]>
> +
> +properties:
> +  compatible:
> +    enum:
> +    - titanmec,tm1628
> +
> +  reg:
> +    maxItems: 1
> +
> +  "#grids":

I'd be more a fan of using '#' prefix if we'd been better at using it 
when appropriate, so I'd probably drop the '#'.

> +    description: |
> +      Number of GRID output lines to use.
> +      This limits the number of available SEG output lines.
> +    minimum: 4
> +    maximum: 7
> +
> +  "#address-cells":
> +    const: 2
> +
> +  "#size-cells":
> +    const: 0
> +
> +required:
> +  - compatible
> +  - reg
> +
> +patternProperties:
> +  "^.*@[1-7],([1-9]|1[02-4])$":
> +    type: object
> +    description: |
> +      Properties for a single LED.

Please describe the unit-address format. I assume it's <grid>,<segment>.

> +
> +    properties:
> +      reg:
> +        description: |
> +          1-based grid number, followed by 1-based segment number.
> +        maxItems: 1
> +
> +      linux,default-trigger: true
> +
> +    required:
> +      - reg
> +
> +examples:
> +  - |
> +    #include <dt-bindings/leds/common.h>
> +
> +    spi {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        led-controller@0 {
> +            compatible = "titanmec,tm1628";
> +            reg = <0>;
> +            spi-3-wire;
> +            spi-lsb-first;
> +            spi-max-frequency = <500000>;
> +            #grids = <7>;
> +            #address-cells = <2>;
> +            #size-cells = <0>;
> +
> +            colon@5,4 {
> +                reg = <5 4>;
> +                color = <LED_COLOR_ID_WHITE>;
> +                function = LED_FUNCTION_INDICATOR;
> +                linux,default-trigger = "heartbeat";
> +            };
> +        };
> +    };
> +...
> -- 
> 2.16.4
> 

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