Re: [PATCH v2 1/2] dt-bindings: display: Add SSD133x OLED controllers

[Javier Martinez Canillas <javierm@redhat.com>]

Conor Dooley <conor@kernel.org> writes:

Hello Conor,

> On Mon, Dec 18, 2023 at 02:20:35PM +0100, Javier Martinez Canillas wrote:

[...]

>> +allOf:
>> +  - $ref: solomon,ssd-common.yaml#
>> +
>> +  - properties:
>> +      width:
>> +        default: 96
>> +      height:
>> +        default: 64
>
> diff --git a/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml b/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml
> index 8feee9eef0fd..ffc939c782eb 100644
> --- a/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml
> +++ b/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml
> @@ -9,24 +9,24 @@ title: Solomon SSD133x OLED Display Controllers
>  maintainers:
>    - Javier Martinez Canillas <javierm@redhat.com>
>  
> +allOf:
> +  - $ref: solomon,ssd-common.yaml#
> +

This part worked correctly...

>  properties:
>    compatible:
>      enum:
>        - solomon,ssd1331
>  
> +  width:
> +    default: 96
> +
> +  height:
> +    default: 64
> +

...but when trying move the default for the "solomon,width" and
"solomon,height" to the properties section, make dt_binding_check
complains as follows:

  LINT    Documentation/devicetree/bindings
  CHKDT   Documentation/devicetree/bindings/processed-schema.json
/home/javier/devel/linux/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml: properties:solomon,height: 'oneOf' conditional failed, one must be fixed:
        'type' is a required property
                hint: A vendor boolean property can use "type: boolean"
        'description' is a required property
                hint: A vendor boolean property can use "type: boolean"
        Additional properties are not allowed ('default' was unexpected)
                hint: A vendor boolean property can use "type: boolean"
        /home/javier/devel/linux/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml: properties:solomon,height: 'oneOf' conditional failed, one must be fixed:
                'enum' is a required property
                'const' is a required property
                hint: A vendor string property with exact values has an implicit type
                from schema $id: http://devicetree.org/meta-schemas/vendor-props.yaml#
        /home/javier/devel/linux/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml: properties:solomon,height: 'oneOf' conditional failed, one must be fixed:
                '$ref' is a required property
                'allOf' is a required property
                hint: A vendor property needs a $ref to types.yaml
                from schema $id: http://devicetree.org/meta-schemas/vendor-props.yaml#
        hint: Vendor specific properties must have a type and description unless they have a defined, common suffix.
        from schema $id: http://devicetree.org/meta-schemas/vendor-props.yaml#
/home/javier/devel/linux/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml: properties:solomon,width: 'oneOf' conditional failed, one must be fixed:
        'type' is a required property
                hint: A vendor boolean property can use "type: boolean"
        'description' is a required property
                hint: A vendor boolean property can use "type: boolean"
        Additional properties are not allowed ('default' was unexpected)
                hint: A vendor boolean property can use "type: boolean"
        /home/javier/devel/linux/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml: properties:solomon,width: 'oneOf' conditional failed, one must be fixed:
                'enum' is a required property
                'const' is a required property
                hint: A vendor string property with exact values has an implicit type
                from schema $id: http://devicetree.org/meta-schemas/vendor-props.yaml#
        /home/javier/devel/linux/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml: properties:solomon,width: 'oneOf' conditional failed, one must be fixed:
                '$ref' is a required property
                'allOf' is a required property
                hint: A vendor property needs a $ref to types.yaml
                from schema $id: http://devicetree.org/meta-schemas/vendor-props.yaml#
        hint: Vendor specific properties must have a type and description unless they have a defined, common suffix.
        from schema $id: http://devicetree.org/meta-schemas/vendor-props.yaml#
  SCHEMA  Documentation/devicetree/bindings/processed-schema.json
  DTEX    Documentation/devicetree/bindings/display/solomon,ssd133x.example.dts
/home/javier/.local/bin/dt-extract-example:75: SyntaxWarning: invalid escape sequence '\s'
  root_node = re.search('/\s*{', ex)
/home/javier/.local/bin/dt-extract-example:79: SyntaxWarning: invalid escape sequence '\s'
  int_val = re.search('\sinterrupts\s*=\s*<([0-9a-zA-Z |()_]+)>', ex).group(1)
  DTC_CHK Documentation/devicetree/bindings/display/solomon,ssd133x.example.dtb

The warning goes away if I follow the hints and add a type and description
to the properties, i.e:

diff --git a/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml b/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml
index 880c71fdec68..0f4d9ca7456b 100644
--- a/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml
+++ b/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml
@@ -17,6 +17,20 @@ properties:
     enum:
       - solomon,ssd1331
 
+  solomon,width:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Width in pixel of the screen driven by the controller.
+      The default value is controller-dependent.
+    default: 96
+
+  solomon,height:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Height in pixel of the screen driven by the controller.
+      The default value is controller-dependent.
+    default: 64
+
 required:
   - compatible
   - reg

But that would duplicate information that is already present in the
included solomon,ssd-common.yaml schema. Do you know what is the proper
way to do this?

Or maybe should I just drop the default values for the width and height
properties? I just think that is good information to have in the schema.

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat