linux-kernel - Re: [v7 1/3] dt-bindings: i2c: Add Maxim MAX735x/MAX736x variants

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Message-ID: <YkxIOgTl876orHbf@pendragon.ideasonboard.com>
Date:   Tue, 5 Apr 2022 16:46:34 +0300
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Patrick Rudolph <patrick.rudolph@...ements.com>
Cc:     Peter Rosin <peda@...ntia.se>, Rob Herring <robh+dt@...nel.org>,
        linux-i2c@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [v7 1/3] dt-bindings: i2c: Add Maxim MAX735x/MAX736x variants

Hi Patrick,

Thank you for the patch.

On Tue, Apr 05, 2022 at 02:05:49PM +0200, Patrick Rudolph wrote:
> Update the pca954x bindings to add support for the Maxim MAX735x/MAX736x
> chips. The functionality will be provided by the exisintg pca954x driver.
> 
> While on it make the interrupts support conditionally as not all of the
> existing chips have interrupts.
> 
> For chips that are powered off by default add an optional regulator
> called vdd-supply.
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@...ements.com>
> ---
>  .../bindings/i2c/i2c-mux-pca954x.yaml         | 44 ++++++++++++++-----
>  1 file changed, 34 insertions(+), 10 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> index 9f1726d0356b..132c3e54e7ab 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml
> @@ -4,21 +4,48 @@
>  $id: http://devicetree.org/schemas/i2c/i2c-mux-pca954x.yaml#
>  $schema: http://devicetree.org/meta-schemas/core.yaml#
>  
> -title: NXP PCA954x I2C bus switch
> +title: NXP PCA954x I2C and compatible bus switches
>  
>  maintainers:
>    - Laurent Pinchart <laurent.pinchart@...asonboard.com>
>  
>  description:
> -  The binding supports NXP PCA954x and PCA984x I2C mux/switch devices.
> +  The binding supports NXP PCA954x and PCA984x I2C mux/switch devices,
> +  and the Maxim MAX735x and MAX736x I2C mux/switch devices.
>  
>  allOf:
>    - $ref: /schemas/i2c/i2c-mux.yaml#
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - maxim,max7367
> +              - maxim,max7369
> +              - nxp,pca9542
> +              - nxp,pca9543
> +              - nxp,pca9544
> +              - nxp,pca9545
> +    then:
> +      properties:
> +        interrupts:
> +          maxItems: 1
> +
> +        "#interrupt-cells":
> +          const: 2
> +
> +        interrupt-controller: true

It feels a bit out of place to have those properties listed before the
main "properties" property, but we can only have a sincel allOf. I
wonder if the i2c-mux schema could be selected automatically based on
node name, but that's out of scope for this patch.

I thought it was more customary to define properties in the main
"properties" property, and then have

if:
  not:
    properties:
      compatible:
        contains:
          enum:
            - maxim,max7367
            - maxim,max7369
            - nxp,pca9542
            - nxp,pca9543
            - nxp,pca9544
            - nxp,pca9545
  then:
    properties:
      interrupts: false
      "#interrupt-cells": false
      interrupt-controller: false

I don't mind much either way though, but if one option is preferred over
the other, we may want to be consistent.

Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>

>  properties:
>    compatible:
>      oneOf:
>        - enum:
> +          - maxim,max7356
> +          - maxim,max7357
> +          - maxim,max7358
> +          - maxim,max7367
> +          - maxim,max7368
> +          - maxim,max7369
>            - nxp,pca9540
>            - nxp,pca9542
>            - nxp,pca9543
> @@ -38,14 +65,6 @@ properties:
>    reg:
>      maxItems: 1
>  
> -  interrupts:
> -    maxItems: 1
> -
> -  "#interrupt-cells":
> -    const: 2
> -
> -  interrupt-controller: true
> -
>    reset-gpios:
>      maxItems: 1
>  
> @@ -59,6 +78,9 @@ properties:
>      description: if present, overrides i2c-mux-idle-disconnect
>      $ref: /schemas/mux/mux-controller.yaml#/properties/idle-state
>  
> +  vdd-supply:
> +    description: A voltage regulator supplying power to the chip.
> +
>  required:
>    - compatible
>    - reg
> @@ -79,6 +101,8 @@ examples:
>              #size-cells = <0>;
>              reg = <0x74>;
>  
> +            vdd-supply = <&p3v3>;
> +
>              interrupt-parent = <&ipic>;
>              interrupts = <17 IRQ_TYPE_LEVEL_LOW>;
>              interrupt-controller;

-- 
Regards,

Laurent Pinchart