[PATCH v2 0/2] drm/solomon: Add support for the SSD133x controller family

[PATCH v2 0/2] drm/solomon: Add support for the SSD133x controller family

[Javier Martinez Canillas]

Hello,

This patch-set adds support for the family of SSD133x Solomon controllers,
such as the SSD1331. These are used for RGB Dot Matrix OLED/PLED panels.

This is a v2 that addresses issues pointed out in v1:

https://lore.kernel.org/lkml/20231217100741.1943932-2-javierm@redhat.com/T/

The patches were tested on a Waveshare SSD1331 display using glmark2-drm,
fbcon, fbtests and the retroarch emulator.

Patch #1 adds a DT binding schema for the SSD133x controllers and patch #2
extends the ssd130x DRM driver to support the SSD133x controller family.

Best regards,
Javier

Changes in v2:
- Unconditionally set the width and height constraints (Conor Dooley).
- Fix indentation in the DTS examples (Krzysztof Kozlowski).

Javier Martinez Canillas (2):
  dt-bindings: display: Add SSD133x OLED controllers
  drm/ssd130x: Add support for the SSD133x OLED controller family

 .../bindings/display/solomon,ssd133x.yaml     |  57 +++
 drivers/gpu/drm/solomon/ssd130x-i2c.c         |   5 +
 drivers/gpu/drm/solomon/ssd130x-spi.c         |   7 +
 drivers/gpu/drm/solomon/ssd130x.c             | 370 ++++++++++++++++++
 drivers/gpu/drm/solomon/ssd130x.h             |   5 +-
 5 files changed, 443 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/display/solomon,ssd133x.yaml

-- 
2.43.0

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

[Javier Martinez Canillas]

Add a Device Tree binding schema for the OLED panels based on the
Solomon SSD133x family of controllers.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
---

Changes in v2:
- Unconditionally set the width and height constraints (Conor Dooley).
- Fix indentation in the DTS examples (Krzysztof Kozlowski).

 .../bindings/display/solomon,ssd133x.yaml     | 57 +++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/solomon,ssd133x.yaml

diff --git a/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml b/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml
new file mode 100644
index 000000000000..8feee9eef0fd
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml
@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/solomon,ssd133x.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Solomon SSD133x OLED Display Controllers
+
+maintainers:
+  - Javier Martinez Canillas <javierm@redhat.com>
+
+properties:
+  compatible:
+    enum:
+      - solomon,ssd1331
+
+required:
+  - compatible
+  - reg
+
+allOf:
+  - $ref: solomon,ssd-common.yaml#
+
+  - properties:
+      width:
+        default: 96
+      height:
+        default: 64
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        oled@3c {
+            compatible = "solomon,ssd1331";
+            reg = <0x3c>;
+            reset-gpios = <&gpio2 7>;
+        };
+
+    };
+  - |
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        oled@0 {
+            compatible = "solomon,ssd1331";
+            reg = <0x0>;
+            reset-gpios = <&gpio2 7>;
+            dc-gpios = <&gpio2 8>;
+            spi-max-frequency = <10000000>;
+        };
+    };
-- 
2.43.0

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

[Conor Dooley]

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On Mon, Dec 18, 2023 at 02:20:35PM +0100, Javier Martinez Canillas wrote:
> Add a Device Tree binding schema for the OLED panels based on the
> Solomon SSD133x family of controllers.
> 
> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
> ---
> 
> Changes in v2:
> - Unconditionally set the width and height constraints (Conor Dooley).
> - Fix indentation in the DTS examples (Krzysztof Kozlowski).
> 
>  .../bindings/display/solomon,ssd133x.yaml     | 57 +++++++++++++++++++
>  1 file changed, 57 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/solomon,ssd133x.yaml
> 
> diff --git a/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml b/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml
> new file mode 100644
> index 000000000000..8feee9eef0fd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/solomon,ssd133x.yaml
> @@ -0,0 +1,57 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/solomon,ssd133x.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Solomon SSD133x OLED Display Controllers
> +
> +maintainers:
> +  - Javier Martinez Canillas <javierm@redhat.com>
> +
> +properties:
> +  compatible:
> +    enum:
> +      - solomon,ssd1331
> +
> +required:
> +  - compatible
> +  - reg
> +
> +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#
+
 properties:
   compatible:
     enum:
       - solomon,ssd1331
 
+  width:
+    default: 96
+
+  height:
+    default: 64
+
 required:
   - compatible
   - reg
 
-allOf:
-  - $ref: solomon,ssd-common.yaml#
-
-  - properties:
-      width:
-        default: 96
-      height:
-        default: 64
-
 unevaluatedProperties: false
 
 examples:

The properties stuff doesn't need to be in the allOf. Although, I took
the opportunity to look at ssd-common.yaml. How do the height/width here
differ from the vendor prefixed versions in that file?

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

[Javier Martinez Canillas]

Conor Dooley <conor@kernel.org> writes:

Hello Conor,

Thanks a lot for your feedback.

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

[...]

>> +
>> +  - 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#
> +
>  properties:
>    compatible:
>      enum:
>        - solomon,ssd1331
>  
> +  width:
> +    default: 96
> +
> +  height:
> +    default: 64
> +
>  required:
>    - compatible
>    - reg
>  
> -allOf:
> -  - $ref: solomon,ssd-common.yaml#
> -
> -  - properties:
> -      width:
> -        default: 96
> -      height:
> -        default: 64
> -
>  unevaluatedProperties: false
>  
>  examples:
>
> The properties stuff doesn't need to be in the allOf. Although, I took

Ok.

> the opportunity to look at ssd-common.yaml. How do the height/width here
> differ from the vendor prefixed versions in that file?

Oh! That is an error in the schema that I introduced when adding the
binding for the SSD132x family in commit 2d23e7d6bacb ("dt-bindings:
display: Add SSD132x OLED controllers"), and I just copied it to this
binding as well making the same mistake...

I'll fix that with a preparatory patch to use "solomon,{width,height}"
everywhere in v3 and also include your suggested changes for this patch.

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat

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

[Javier Martinez Canillas]

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

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

[Krzysztof Kozlowski]

On 19/12/2023 12:20, Javier Martinez Canillas wrote:
> 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

Which also looks wrong on its own. Where is the definition of these
properties? IOW, where do they come from?

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

Worked for me.

...

>   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:

Hm, I wonder what's different in your case. I assume you run the latest
dtschema.

> 
> 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?

Works for me, so please paste somewhere proper diff so we can compare.

Best regards,
Krzysztof

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

[Javier Martinez Canillas]

Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> writes:

Hello Krzysztof,

> On 19/12/2023 12:20, Javier Martinez Canillas wrote:

[...]

>>>> +allOf:
>>>> +  - $ref: solomon,ssd-common.yaml#
>>>> +

[...]

>>>  
>>> +  width:
>>> +    default: 96
>>> +
>>> +  height:
>>> +    default: 64
>
> Which also looks wrong on its own. Where is the definition of these

Yes, I already discussed this with Conor and mentioned to him that is a
typo but already fixed it locally and I'm testing with the correct ones.

> properties? IOW, where do they come from?
>

The "solomon,width" and "solomon,height" properties are defined in the
solomon,ssd-common.yaml binding schema file that is referenced.

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

Oh, that's good to know. I wonder what's the difference...

> ...
>
>>   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:
>
> Hm, I wonder what's different in your case. I assume you run the latest
> dtschema.
>

Not the latest but had a recent one. I've updated it, so I do now :)

$ pip list | grep dtschema
dtschema                      2023.9

$ pip install --upgrade dtschema

$ pip list | grep dtschema
dtschema                      2023.11

[...]

>> 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?
>
> Works for me, so please paste somewhere proper diff so we can compare.
>

With the latest dtschema version it works indeed. Thanks for the pointer!

$ make W=1 dt_binding_check DT_SCHEMA_FILES=Documentation/devicetree/bindings/display/solomon,ssd133x.yaml 
  LINT    Documentation/devicetree/bindings
  CHKDT   Documentation/devicetree/bindings/processed-schema.json
  SCHEMA  Documentation/devicetree/bindings/processed-schema.json
  DTEX    Documentation/devicetree/bindings/display/solomon,ssd133x.example.dts
  DTC_CHK Documentation/devicetree/bindings/display/solomon,ssd133x.example.dtb

> Best regards,
> Krzysztof
>

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat