[RFC,3/4] dt-bindings: panel: Introduce dual-link LVDS panel

  Dual-link LVDS interfaces have 2 links, with even pixels traveling on
one link, and odd pixels on the other. These panels are also generic in
nature, with no documented constraints, much like their single-link
counterparts, "panel-lvds".

Add a new compatible, "panel-dual-lvds", and a dt-binding document for
these panels.

Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
---
 .../display/panel/panel-dual-lvds.yaml        | 157 ++++++++++++++++++
 MAINTAINERS                                   |   1 +
 2 files changed, 158 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
  

On 03/01/2023 07:46, Aradhya Bhatia wrote:
> Dual-link LVDS interfaces have 2 links, with even pixels traveling on
> one link, and odd pixels on the other. These panels are also generic in
> nature, with no documented constraints, much like their single-link
> counterparts, "panel-lvds".
> 
> Add a new compatible, "panel-dual-lvds", and a dt-binding document for
> these panels.
> 
> Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
> ---
>  .../display/panel/panel-dual-lvds.yaml        | 157 ++++++++++++++++++
>  MAINTAINERS                                   |   1 +
>  2 files changed, 158 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
> 
> diff --git a/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
> new file mode 100644
> index 000000000000..88a7aa2410be
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
> @@ -0,0 +1,157 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/panel/panel-dual-lvds.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Generic Dual-Link LVDS Display Panel
> +
> +maintainers:
> +  - Aradhya Bhatia <a-bhatia1@ti.com>
> +  - Thierry Reding <thierry.reding@gmail.com>
> +
> +description: |
> +  A dual-LVDS interface is a dual-link connection with the even pixels
> +  traveling on one link, and the odd pixels traveling on the other.
> +
> +allOf:
> +  - $ref: panel-common.yaml#
> +  - $ref: /schemas/display/lvds.yaml/#

Drop trailing /

> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - items:
> +          - enum:
> +              - lincolntech,lcd185-101ct
> +              - microtips,13-101hieb0hf0-s
> +          - const: panel-dual-lvds
> +      - const: panel-dual-lvds

You cannot have this compatible alone.

> +
> +  ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +
> +    properties:
> +      port@0:
> +        $ref: /schemas/graph.yaml#/$defs/port-base
> +        unevaluatedProperties: false
> +        description: The sink for first set of LVDS pixels.
> +
> +        properties:
> +          dual-lvds-odd-pixels:
> +            type: boolean
> +
> +          dual-lvds-even-pixels:
> +            type: boolean
> +
> +        oneOf:
> +          - required: [dual-lvds-odd-pixels]
> +          - required: [dual-lvds-even-pixels]
> +
> +      port@1:
> +        $ref: /schemas/graph.yaml#/$defs/port-base
> +        unevaluatedProperties: false
> +        description: The sink for second set of LVDS pixels.
> +
> +        properties:
> +          dual-lvds-even-pixels:
> +            type: boolean
> +
> +          dual-lvds-odd-pixels:
> +            type: boolean
> +
> +        oneOf:
> +          - required: [dual-lvds-even-pixels]
> +          - required: [dual-lvds-odd-pixels]
> +
> +    allOf:
> +      - if:
> +          properties:
> +            port@0:
> +              properties:
> +                dual-lvds-odd-pixels: true

That's not correct clause. It has no effect.

> +              required:
> +                - dual-lvds-odd-pixels
> +        then:
> +          properties:
> +            port@1:
> +              properties:
> +                dual-lvds-even-pixels: true
> +                dual-lvds-odd-pixels: false

Why do you need this? Your oneOf before already solves it.

> +
> +      - if:
> +          properties:
> +            port@0:
> +              properties:
> +                dual-lvds-even-pixels: true
> +              required:
> +                - dual-lvds-even-pixels
> +        then:
> +          properties:
> +            port@1:
> +              properties:
> +                dual-lvds-odd-pixels: true
> +                dual-lvds-even-pixels: false
> +
> +    required:
> +      - port@0
> +      - port@1
> +
> +  port: false
> +
> +unevaluatedProperties: false
> +
> +required:
> +  - compatible
> +  - width-mm
> +  - height-mm
> +  - data-mapping
> +  - panel-timing
> +  - ports
> +
> +examples:
> +  - |+

Drop +

> +    panel-dual-lvds {

Just "panel". Node names should be generic.

> +      compatible = "microtips,13-101hieb0hf0-s", "panel-dual-lvds";
> +
> +      width-mm = <217>;
> +      height-mm = <136>;
> +

Best regards,
Krzysztof
  

Hi Krzysztof,

Thank you for reviewing the patches!

On 03-Jan-23 14:02, Krzysztof Kozlowski wrote:
> On 03/01/2023 07:46, Aradhya Bhatia wrote:
>> Dual-link LVDS interfaces have 2 links, with even pixels traveling on
>> one link, and odd pixels on the other. These panels are also generic in
>> nature, with no documented constraints, much like their single-link
>> counterparts, "panel-lvds".
>>
>> Add a new compatible, "panel-dual-lvds", and a dt-binding document for
>> these panels.
>>
>> Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
>> ---
>>   .../display/panel/panel-dual-lvds.yaml        | 157 ++++++++++++++++++
>>   MAINTAINERS                                   |   1 +
>>   2 files changed, 158 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>> new file mode 100644
>> index 000000000000..88a7aa2410be
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>> @@ -0,0 +1,157 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/display/panel/panel-dual-lvds.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Generic Dual-Link LVDS Display Panel
>> +
>> +maintainers:
>> +  - Aradhya Bhatia <a-bhatia1@ti.com>
>> +  - Thierry Reding <thierry.reding@gmail.com>
>> +
>> +description: |
>> +  A dual-LVDS interface is a dual-link connection with the even pixels
>> +  traveling on one link, and the odd pixels traveling on the other.
>> +
>> +allOf:
>> +  - $ref: panel-common.yaml#
>> +  - $ref: /schemas/display/lvds.yaml/#
> 
> Drop trailing /

Okay, will do!

> 
>> +
>> +properties:
>> +  compatible:
>> +    oneOf:
>> +      - items:
>> +          - enum:
>> +              - lincolntech,lcd185-101ct
>> +              - microtips,13-101hieb0hf0-s
>> +          - const: panel-dual-lvds
>> +      - const: panel-dual-lvds
> 
> You cannot have this compatible alone
Okay, will make the change!

> 
>> +
>> +  ports:
>> +    $ref: /schemas/graph.yaml#/properties/ports
>> +
>> +    properties:
>> +      port@0:
>> +        $ref: /schemas/graph.yaml#/$defs/port-base
>> +        unevaluatedProperties: false
>> +        description: The sink for first set of LVDS pixels.
>> +
>> +        properties:
>> +          dual-lvds-odd-pixels:
>> +            type: boolean
>> +
>> +          dual-lvds-even-pixels:
>> +            type: boolean
>> +
>> +        oneOf:
>> +          - required: [dual-lvds-odd-pixels]
>> +          - required: [dual-lvds-even-pixels]
>> +
>> +      port@1:
>> +        $ref: /schemas/graph.yaml#/$defs/port-base
>> +        unevaluatedProperties: false
>> +        description: The sink for second set of LVDS pixels.
>> +
>> +        properties:
>> +          dual-lvds-even-pixels:
>> +            type: boolean
>> +
>> +          dual-lvds-odd-pixels:
>> +            type: boolean
>> +
>> +        oneOf:
>> +          - required: [dual-lvds-even-pixels]
>> +          - required: [dual-lvds-odd-pixels]
>> +
>> +    allOf:
>> +      - if:
>> +          properties:
>> +            port@0:
>> +              properties:
>> +                dual-lvds-odd-pixels: true
> 
> That's not correct clause. It has no effect.

The idea behind this is to check the presence of the boolean property.

if (dual-lvds-odd-pixels is present)
then
[..]


I tried implementing this:

	[..]
	  dual-lvds-odd-pixels:
	    - const: true
	[..]

But this is throwing an error. I am confused what else could be done.
Can you please suggest what might be a more accurate check here?

> 
>> +              required:
>> +                - dual-lvds-odd-pixels
>> +        then:
>> +          properties:
>> +            port@1:
>> +              properties:
>> +                dual-lvds-even-pixels: true
>> +                dual-lvds-odd-pixels: false
> 
> Why do you need this? Your oneOf before already solves it.

I agree with your comment here. It makes sense to only have

	dual-lvds-even-pixels: true

and have the oneOf condition take care of the other. But, I just tested
this and it was unable to pick-up this intentionally-added error.

I added 'dual-lvds-odd-pixels' property to both the nodes, and
dt_binding_check passes successfully (which it should have not.)

Instead, if I only keep this,

	dual-lvds-odd-pixels: false

then the dt_binding_check detects the error as it should.

Regardless, I am curious why the first method doesn't work. Will try to
explore more on that.

> 
>> +
>> +      - if:
>> +          properties:
>> +            port@0:
>> +              properties:
>> +                dual-lvds-even-pixels: true
>> +              required:
>> +                - dual-lvds-even-pixels
>> +        then:
>> +          properties:
>> +            port@1:
>> +              properties:
>> +                dual-lvds-odd-pixels: true
>> +                dual-lvds-even-pixels: false
>> +
>> +    required:
>> +      - port@0
>> +      - port@1
>> +
>> +  port: false
>> +
>> +unevaluatedProperties: false
>> +
>> +required:
>> +  - compatible
>> +  - width-mm
>> +  - height-mm
>> +  - data-mapping
>> +  - panel-timing
>> +  - ports
>> +
>> +examples:
>> +  - |+
> 
> Drop +

Okay!

> 
>> +    panel-dual-lvds {
> 
> Just "panel". Node names should be generic.

Alright. Will make the change!

> 
>> +      compatible = "microtips,13-101hieb0hf0-s", "panel-dual-lvds";
>> +
>> +      width-mm = <217>;
>> +      height-mm = <136>;
>> +
> 
Regards
Aradhya
  

On 03/01/2023 12:02, Aradhya Bhatia wrote:
> But this is throwing an error. I am confused what else could be done.
> Can you please suggest what might be a more accurate check here?
> 
>>
>>> +              required:
>>> +                - dual-lvds-odd-pixels
>>> +        then:
>>> +          properties:
>>> +            port@1:
>>> +              properties:
>>> +                dual-lvds-even-pixels: true
>>> +                dual-lvds-odd-pixels: false
>>
>> Why do you need this? Your oneOf before already solves it.
> 
> I agree with your comment here. It makes sense to only have
> 
> 	dual-lvds-even-pixels: true
> 
> and have the oneOf condition take care of the other. But, I just tested
> this and it was unable to pick-up this intentionally-added error.
> 
> I added 'dual-lvds-odd-pixels' property to both the nodes, and
> dt_binding_check passes successfully (which it should have not.)
> 
> Instead, if I only keep this,
> 
> 	dual-lvds-odd-pixels: false
> 
> then the dt_binding_check detects the error as it should.
> 
> Regardless, I am curious why the first method doesn't work. Will try to
> explore more on that.

The check for presence of properties is only against required:, but you
added there properties. Like this:

https://elixir.bootlin.com/linux/v5.17-rc2/source/Documentation/devicetree/bindings/mfd/samsung,s5m8767.yaml#L155


Other way is to drop your both oneOf and entire allOf from ports and use:

oneOf:
  - properties:
      ports:
        $ref: /schemas/graph.yaml#/properties/ports
        properties:
          port@0:
            required:
              - dual-lvds-odd-pixels
          port@1:
            required:
              - dual-lvds-even-pixels
  - properties:
      ports:
        $ref: /schemas/graph.yaml#/properties/ports
        properties:
          port@1:
            required:
              - dual-lvds-odd-pixels
          port@0:
            required:
              - dual-lvds-even-pixels


Best regards,
Krzysztof
  

Il 03/01/23 07:46, Aradhya Bhatia ha scritto:
> Dual-link LVDS interfaces have 2 links, with even pixels traveling on
> one link, and odd pixels on the other. These panels are also generic in
> nature, with no documented constraints, much like their single-link
> counterparts, "panel-lvds".
> 
> Add a new compatible, "panel-dual-lvds", and a dt-binding document for
> these panels.
> 
> Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
> ---
>   .../display/panel/panel-dual-lvds.yaml        | 157 ++++++++++++++++++
>   MAINTAINERS                                   |   1 +
>   2 files changed, 158 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
> 
> diff --git a/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
> new file mode 100644
> index 000000000000..88a7aa2410be
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
> @@ -0,0 +1,157 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/panel/panel-dual-lvds.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Generic Dual-Link LVDS Display Panel
> +
> +maintainers:
> +  - Aradhya Bhatia <a-bhatia1@ti.com>
> +  - Thierry Reding <thierry.reding@gmail.com>
> +
> +description: |
> +  A dual-LVDS interface is a dual-link connection with the even pixels
> +  traveling on one link, and the odd pixels traveling on the other.
> +
> +allOf:
> +  - $ref: panel-common.yaml#
> +  - $ref: /schemas/display/lvds.yaml/#
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - items:
> +          - enum:
> +              - lincolntech,lcd185-101ct
> +              - microtips,13-101hieb0hf0-s
> +          - const: panel-dual-lvds
> +      - const: panel-dual-lvds
> +
> +  ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +
> +    properties:
> +      port@0:
> +        $ref: /schemas/graph.yaml#/$defs/port-base
> +        unevaluatedProperties: false
> +        description: The sink for first set of LVDS pixels.
> +
> +        properties:
> +          dual-lvds-odd-pixels:
> +            type: boolean
> +
> +          dual-lvds-even-pixels:
> +            type: boolean
> +
> +        oneOf:
> +          - required: [dual-lvds-odd-pixels]

One question: why do we need a "panel-dual-lvds" compatible?
A Dual-LVDS panel is a LVDS panel using two ports, hence still a panel-lvds.

If you're doing this to clearly distinguish, for human readability purposes,
single-link vs dual-link panels, I think that this would still be clear even
if we use panel-lvds alone because dual-link panels, as you wrote in this
binding, does *require* two ports, with "dual-lvds-{odd,even}-pixels" properties.

So... the devicetree node would look like this:

panel {
	compatible = "vendor,panel", "panel-lvds";
	....
	ports {
		port@0 {
			.....
			-> dual-lvds-odd-pixels <-
		}

		port@1 {
			.....
			-> dual-lvds-even-pixels <-
		};
	};
};

> +          - required: [dual-lvds-even-pixels]

...Though, if you expect dual-lvds panels to get other quirks in the future,
that's a whole different story and you may actually need the panel-dual-lvds
compatible.

Regards,
Angelo
  

Hi Aradhya,

Thank you for the patch.

On Tue, Jan 03, 2023 at 12:16:14PM +0530, Aradhya Bhatia wrote:
> Dual-link LVDS interfaces have 2 links, with even pixels traveling on
> one link, and odd pixels on the other. These panels are also generic in
> nature, with no documented constraints, much like their single-link
> counterparts, "panel-lvds".
> 
> Add a new compatible, "panel-dual-lvds", and a dt-binding document for
> these panels.
> 
> Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
> ---
>  .../display/panel/panel-dual-lvds.yaml        | 157 ++++++++++++++++++
>  MAINTAINERS                                   |   1 +
>  2 files changed, 158 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
> 
> diff --git a/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
> new file mode 100644
> index 000000000000..88a7aa2410be
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
> @@ -0,0 +1,157 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/panel/panel-dual-lvds.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Generic Dual-Link LVDS Display Panel
> +
> +maintainers:
> +  - Aradhya Bhatia <a-bhatia1@ti.com>
> +  - Thierry Reding <thierry.reding@gmail.com>
> +
> +description: |
> +  A dual-LVDS interface is a dual-link connection with the even pixels
> +  traveling on one link, and the odd pixels traveling on the other.
> +
> +allOf:
> +  - $ref: panel-common.yaml#
> +  - $ref: /schemas/display/lvds.yaml/#
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - items:
> +          - enum:
> +              - lincolntech,lcd185-101ct
> +              - microtips,13-101hieb0hf0-s
> +          - const: panel-dual-lvds
> +      - const: panel-dual-lvds

A device-specific compatible string should be required,
"panel-dual-lvds" alone shouldn't be allowed. Otherwise it won't be
possible to tell different models apart later should this be required.

> +
> +  ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +
> +    properties:
> +      port@0:
> +        $ref: /schemas/graph.yaml#/$defs/port-base
> +        unevaluatedProperties: false
> +        description: The sink for first set of LVDS pixels.
> +
> +        properties:
> +          dual-lvds-odd-pixels:
> +            type: boolean
> +
> +          dual-lvds-even-pixels:
> +            type: boolean
> +
> +        oneOf:
> +          - required: [dual-lvds-odd-pixels]
> +          - required: [dual-lvds-even-pixels]
> +
> +      port@1:
> +        $ref: /schemas/graph.yaml#/$defs/port-base
> +        unevaluatedProperties: false
> +        description: The sink for second set of LVDS pixels.
> +
> +        properties:
> +          dual-lvds-even-pixels:
> +            type: boolean
> +
> +          dual-lvds-odd-pixels:
> +            type: boolean
> +
> +        oneOf:
> +          - required: [dual-lvds-even-pixels]
> +          - required: [dual-lvds-odd-pixels]
> +
> +    allOf:
> +      - if:
> +          properties:
> +            port@0:
> +              properties:
> +                dual-lvds-odd-pixels: true
> +              required:
> +                - dual-lvds-odd-pixels
> +        then:
> +          properties:
> +            port@1:
> +              properties:
> +                dual-lvds-even-pixels: true
> +                dual-lvds-odd-pixels: false
> +
> +      - if:
> +          properties:
> +            port@0:
> +              properties:
> +                dual-lvds-even-pixels: true
> +              required:
> +                - dual-lvds-even-pixels
> +        then:
> +          properties:
> +            port@1:
> +              properties:
> +                dual-lvds-odd-pixels: true
> +                dual-lvds-even-pixels: false
> +
> +    required:
> +      - port@0
> +      - port@1
> +
> +  port: false
> +
> +unevaluatedProperties: false
> +
> +required:
> +  - compatible
> +  - width-mm
> +  - height-mm
> +  - data-mapping
> +  - panel-timing
> +  - ports
> +
> +examples:
> +  - |+
> +    panel-dual-lvds {
> +      compatible = "microtips,13-101hieb0hf0-s", "panel-dual-lvds";
> +
> +      width-mm = <217>;
> +      height-mm = <136>;
> +
> +      data-mapping = "vesa-24";
> +
> +      panel-timing {
> +        clock-frequency = <150275000>;
> +        hactive = <1920>;
> +        vactive = <1200>;
> +        hfront-porch = <32>;
> +        hsync-len = <52>;
> +        hback-porch = <24>;
> +        vfront-porch = <24>;
> +        vsync-len = <8>;
> +        vback-porch = <3>;
> +        de-active = <1>;
> +      };
> +
> +      ports {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        port@0 {
> +          reg = <0>;
> +          dual-lvds-odd-pixels;
> +          lcd_in0: endpoint {
> +            remote-endpoint = <&oldi_out0>;
> +          };
> +        };
> +
> +        port@1 {
> +          reg = <1>;
> +          dual-lvds-even-pixels;
> +          lcd_in1: endpoint {
> +            remote-endpoint = <&oldi_out1>;
> +          };
> +        };
> +      };
> +    };
> +
> +...
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 7f86d02cb427..c13f24293ab1 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6595,6 +6595,7 @@ T:	git git://anongit.freedesktop.org/drm/drm-misc
>  S:	Maintained
>  F:	drivers/gpu/drm/panel/panel-lvds.c
>  F:	Documentation/devicetree/bindings/display/lvds.yaml
> +F:	Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>  F:	Documentation/devicetree/bindings/display/panel/panel-lvds.yaml
>  
>  DRM DRIVER FOR MANTIX MLAF057WE51 PANELS
  

Hi Krzysztof,

On 03-Jan-23 16:58, Krzysztof Kozlowski wrote:
> On 03/01/2023 12:02, Aradhya Bhatia wrote:
>> But this is throwing an error. I am confused what else could be done.
>> Can you please suggest what might be a more accurate check here?
>>
>>>
>>>> +              required:
>>>> +                - dual-lvds-odd-pixels
>>>> +        then:
>>>> +          properties:
>>>> +            port@1:
>>>> +              properties:
>>>> +                dual-lvds-even-pixels: true
>>>> +                dual-lvds-odd-pixels: false
>>>
>>> Why do you need this? Your oneOf before already solves it.
>>
>> I agree with your comment here. It makes sense to only have
>>
>> 	dual-lvds-even-pixels: true
>>
>> and have the oneOf condition take care of the other. But, I just tested
>> this and it was unable to pick-up this intentionally-added error.
>>
>> I added 'dual-lvds-odd-pixels' property to both the nodes, and
>> dt_binding_check passes successfully (which it should have not.)
>>
>> Instead, if I only keep this,
>>
>> 	dual-lvds-odd-pixels: false
>>
>> then the dt_binding_check detects the error as it should.
>>
>> Regardless, I am curious why the first method doesn't work. Will try to
>> explore more on that.
> 
> The check for presence of properties is only against required:, but you
> added there properties. Like this:
> 
> https://elixir.bootlin.com/linux/v5.17-rc2/source/Documentation/devicetree/bindings/mfd/samsung,s5m8767.yaml#L155
> 
> 
> Other way is to drop your both oneOf and entire allOf from ports and use:
> 
> oneOf:
>    - properties:
>        ports:
>          $ref: /schemas/graph.yaml#/properties/ports
>          properties:
>            port@0:
>              required:
>                - dual-lvds-odd-pixels
>            port@1:
>              required:
>                - dual-lvds-even-pixels
>    - properties:
>        ports:
>          $ref: /schemas/graph.yaml#/properties/ports
>          properties:
>            port@1:
>              required:
>                - dual-lvds-odd-pixels
>            port@0:
>              required:
>                - dual-lvds-even-pixels
> 

Thank you for the suggestions.
I tested the both of them, and they seem to be working as expected.

V2 will reflect all the required fixes.


Regards
Aradhya
  

Hi Angelo,

Thanks for taking a look at the patches!

On 03-Jan-23 17:21, AngeloGioacchino Del Regno wrote:
> Il 03/01/23 07:46, Aradhya Bhatia ha scritto:
>> Dual-link LVDS interfaces have 2 links, with even pixels traveling on
>> one link, and odd pixels on the other. These panels are also generic in
>> nature, with no documented constraints, much like their single-link
>> counterparts, "panel-lvds".
>>
>> Add a new compatible, "panel-dual-lvds", and a dt-binding document for
>> these panels.
>>
>> Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
>> ---
>>   .../display/panel/panel-dual-lvds.yaml        | 157 ++++++++++++++++++
>>   MAINTAINERS                                   |   1 +
>>   2 files changed, 158 insertions(+)
>>   create mode 100644 
>> Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>>
>> diff --git 
>> a/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml 
>> b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>> new file mode 100644
>> index 000000000000..88a7aa2410be
>> --- /dev/null
>> +++ 
>> b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>> @@ -0,0 +1,157 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/display/panel/panel-dual-lvds.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Generic Dual-Link LVDS Display Panel
>> +
>> +maintainers:
>> +  - Aradhya Bhatia <a-bhatia1@ti.com>
>> +  - Thierry Reding <thierry.reding@gmail.com>
>> +
>> +description: |
>> +  A dual-LVDS interface is a dual-link connection with the even pixels
>> +  traveling on one link, and the odd pixels traveling on the other.
>> +
>> +allOf:
>> +  - $ref: panel-common.yaml#
>> +  - $ref: /schemas/display/lvds.yaml/#
>> +
>> +properties:
>> +  compatible:
>> +    oneOf:
>> +      - items:
>> +          - enum:
>> +              - lincolntech,lcd185-101ct
>> +              - microtips,13-101hieb0hf0-s
>> +          - const: panel-dual-lvds
>> +      - const: panel-dual-lvds
>> +
>> +  ports:
>> +    $ref: /schemas/graph.yaml#/properties/ports
>> +
>> +    properties:
>> +      port@0:
>> +        $ref: /schemas/graph.yaml#/$defs/port-base
>> +        unevaluatedProperties: false
>> +        description: The sink for first set of LVDS pixels.
>> +
>> +        properties:
>> +          dual-lvds-odd-pixels:
>> +            type: boolean
>> +
>> +          dual-lvds-even-pixels:
>> +            type: boolean
>> +
>> +        oneOf:
>> +          - required: [dual-lvds-odd-pixels]
> 
> One question: why do we need a "panel-dual-lvds" compatible?
> A Dual-LVDS panel is a LVDS panel using two ports, hence still a panel-lvds.
> 
> If you're doing this to clearly distinguish, for human readability purposes,
> single-link vs dual-link panels, I think that this would still be clear even
> if we use panel-lvds alone because dual-link panels, as you wrote in this
> binding, does *require* two ports, with "dual-lvds-{odd,even}-pixels" properties.

Yes, while they are both LVDS based panels the extra LVDS sink in these
panels, and the capability to decode and display the 2 sets of signals
are enough hardware differences that warrant for an addition of a new
compatible.

> 
> So... the devicetree node would look like this:
> 
> panel {
>      compatible = "vendor,panel", "panel-lvds";
>      ....
>      ports {
>          port@0 {
>              .....
>              -> dual-lvds-odd-pixels <-
>          }
> 
>          port@1 {
>              .....
>              -> dual-lvds-even-pixels <-
>          };
>      };
> };
> 
>> +          - required: [dual-lvds-even-pixels]
> 
> ...Though, if you expect dual-lvds panels to get other quirks in the future,
> that's a whole different story and you may actually need the panel-dual-lvds
> compatible.

Yes, exactly. Even while being non-smart, there are going to be more
quirks in future. And it would be better if they have their own
compatible/binding, and are not getting appended in an ever-growing
if-else ladder. :)


Regards
Aradhya
  

Hi Laurent,

Thank you for reviewing the patches!

On 08-Jan-23 12:26, Laurent Pinchart wrote:
> Hi Aradhya,
> 
> Thank you for the patch.
> 
> On Tue, Jan 03, 2023 at 12:16:14PM +0530, Aradhya Bhatia wrote:
>> Dual-link LVDS interfaces have 2 links, with even pixels traveling on
>> one link, and odd pixels on the other. These panels are also generic in
>> nature, with no documented constraints, much like their single-link
>> counterparts, "panel-lvds".
>>
>> Add a new compatible, "panel-dual-lvds", and a dt-binding document for
>> these panels.
>>
>> Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
>> ---
>>   .../display/panel/panel-dual-lvds.yaml        | 157 ++++++++++++++++++
>>   MAINTAINERS                                   |   1 +
>>   2 files changed, 158 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>> new file mode 100644
>> index 000000000000..88a7aa2410be
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>> @@ -0,0 +1,157 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/display/panel/panel-dual-lvds.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Generic Dual-Link LVDS Display Panel
>> +
>> +maintainers:
>> +  - Aradhya Bhatia <a-bhatia1@ti.com>
>> +  - Thierry Reding <thierry.reding@gmail.com>
>> +
>> +description: |
>> +  A dual-LVDS interface is a dual-link connection with the even pixels
>> +  traveling on one link, and the odd pixels traveling on the other.
>> +
>> +allOf:
>> +  - $ref: panel-common.yaml#
>> +  - $ref: /schemas/display/lvds.yaml/#
>> +
>> +properties:
>> +  compatible:
>> +    oneOf:
>> +      - items:
>> +          - enum:
>> +              - lincolntech,lcd185-101ct
>> +              - microtips,13-101hieb0hf0-s
>> +          - const: panel-dual-lvds
>> +      - const: panel-dual-lvds
> 
> A device-specific compatible string should be required,
> "panel-dual-lvds" alone shouldn't be allowed. Otherwise it won't be
> possible to tell different models apart later should this be required.
> 

Understood! Will make the fix in the next revision.

>> +
>> +  ports:
>> +    $ref: /schemas/graph.yaml#/properties/ports
>> +
>> +    properties:
>> +      port@0:
>> +        $ref: /schemas/graph.yaml#/$defs/port-base
>> +        unevaluatedProperties: false
>> +        description: The sink for first set of LVDS pixels.
>> +
>> +        properties:
>> +          dual-lvds-odd-pixels:
>> +            type: boolean
>> +
>> +          dual-lvds-even-pixels:
>> +            type: boolean
>> +
>> +        oneOf:
>> +          - required: [dual-lvds-odd-pixels]
>> +          - required: [dual-lvds-even-pixels]
>> +
>> +      port@1:
>> +        $ref: /schemas/graph.yaml#/$defs/port-base
>> +        unevaluatedProperties: false
>> +        description: The sink for second set of LVDS pixels.
>> +
>> +        properties:
>> +          dual-lvds-even-pixels:
>> +            type: boolean
>> +
>> +          dual-lvds-odd-pixels:
>> +            type: boolean
>> +
>> +        oneOf:
>> +          - required: [dual-lvds-even-pixels]
>> +          - required: [dual-lvds-odd-pixels]
>> +
>> +    allOf:
>> +      - if:
>> +          properties:
>> +            port@0:
>> +              properties:
>> +                dual-lvds-odd-pixels: true
>> +              required:
>> +                - dual-lvds-odd-pixels
>> +        then:
>> +          properties:
>> +            port@1:
>> +              properties:
>> +                dual-lvds-even-pixels: true
>> +                dual-lvds-odd-pixels: false
>> +
>> +      - if:
>> +          properties:
>> +            port@0:
>> +              properties:
>> +                dual-lvds-even-pixels: true
>> +              required:
>> +                - dual-lvds-even-pixels
>> +        then:
>> +          properties:
>> +            port@1:
>> +              properties:
>> +                dual-lvds-odd-pixels: true
>> +                dual-lvds-even-pixels: false
>> +
>> +    required:
>> +      - port@0
>> +      - port@1
>> +
>> +  port: false
>> +
>> +unevaluatedProperties: false
>> +
>> +required:
>> +  - compatible
>> +  - width-mm
>> +  - height-mm
>> +  - data-mapping
>> +  - panel-timing
>> +  - ports
>> +
>> +examples:
>> +  - |+
>> +    panel-dual-lvds {
>> +      compatible = "microtips,13-101hieb0hf0-s", "panel-dual-lvds";
>> +
>> +      width-mm = <217>;
>> +      height-mm = <136>;
>> +
>> +      data-mapping = "vesa-24";
>> +
>> +      panel-timing {
>> +        clock-frequency = <150275000>;
>> +        hactive = <1920>;
>> +        vactive = <1200>;
>> +        hfront-porch = <32>;
>> +        hsync-len = <52>;
>> +        hback-porch = <24>;
>> +        vfront-porch = <24>;
>> +        vsync-len = <8>;
>> +        vback-porch = <3>;
>> +        de-active = <1>;
>> +      };
>> +
>> +      ports {
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
>> +
>> +        port@0 {
>> +          reg = <0>;
>> +          dual-lvds-odd-pixels;
>> +          lcd_in0: endpoint {
>> +            remote-endpoint = <&oldi_out0>;
>> +          };
>> +        };
>> +
>> +        port@1 {
>> +          reg = <1>;
>> +          dual-lvds-even-pixels;
>> +          lcd_in1: endpoint {
>> +            remote-endpoint = <&oldi_out1>;
>> +          };
>> +        };
>> +      };
>> +    };
>> +
>> +...
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 7f86d02cb427..c13f24293ab1 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -6595,6 +6595,7 @@ T:	git git://anongit.freedesktop.org/drm/drm-misc
>>   S:	Maintained
>>   F:	drivers/gpu/drm/panel/panel-lvds.c
>>   F:	Documentation/devicetree/bindings/display/lvds.yaml
>> +F:	Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>>   F:	Documentation/devicetree/bindings/display/panel/panel-lvds.yaml
>>   
>>   DRM DRIVER FOR MANTIX MLAF057WE51 PANELS
> 

Regards
Aradhya
  

On 09/01/2023 18:21, Aradhya Bhatia wrote:
> Hi Angelo,
> 
> Thanks for taking a look at the patches!
> 
> On 03-Jan-23 17:21, AngeloGioacchino Del Regno wrote:
>> Il 03/01/23 07:46, Aradhya Bhatia ha scritto:
>>> Dual-link LVDS interfaces have 2 links, with even pixels traveling on
>>> one link, and odd pixels on the other. These panels are also generic in
>>> nature, with no documented constraints, much like their single-link
>>> counterparts, "panel-lvds".
>>>
>>> Add a new compatible, "panel-dual-lvds", and a dt-binding document for
>>> these panels.
>>>
>>> Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
>>> ---
>>>   .../display/panel/panel-dual-lvds.yaml        | 157 ++++++++++++++++++
>>>   MAINTAINERS                                   |   1 +
>>>   2 files changed, 158 insertions(+)
>>>   create mode 100644 
>>> Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>>>
>>> diff --git 
>>> a/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>>> new file mode 100644
>>> index 000000000000..88a7aa2410be
>>> --- /dev/null
>>> +++ 
>>> b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>>> @@ -0,0 +1,157 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/display/panel/panel-dual-lvds.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: Generic Dual-Link LVDS Display Panel
>>> +
>>> +maintainers:
>>> +  - Aradhya Bhatia <a-bhatia1@ti.com>
>>> +  - Thierry Reding <thierry.reding@gmail.com>
>>> +
>>> +description: |
>>> +  A dual-LVDS interface is a dual-link connection with the even pixels
>>> +  traveling on one link, and the odd pixels traveling on the other.
>>> +
>>> +allOf:
>>> +  - $ref: panel-common.yaml#
>>> +  - $ref: /schemas/display/lvds.yaml/#
>>> +
>>> +properties:
>>> +  compatible:
>>> +    oneOf:
>>> +      - items:
>>> +          - enum:
>>> +              - lincolntech,lcd185-101ct
>>> +              - microtips,13-101hieb0hf0-s
>>> +          - const: panel-dual-lvds
>>> +      - const: panel-dual-lvds
>>> +
>>> +  ports:
>>> +    $ref: /schemas/graph.yaml#/properties/ports
>>> +
>>> +    properties:
>>> +      port@0:
>>> +        $ref: /schemas/graph.yaml#/$defs/port-base
>>> +        unevaluatedProperties: false
>>> +        description: The sink for first set of LVDS pixels.
>>> +
>>> +        properties:
>>> +          dual-lvds-odd-pixels:
>>> +            type: boolean
>>> +
>>> +          dual-lvds-even-pixels:
>>> +            type: boolean
>>> +
>>> +        oneOf:
>>> +          - required: [dual-lvds-odd-pixels]
>>
>> One question: why do we need a "panel-dual-lvds" compatible?
>> A Dual-LVDS panel is a LVDS panel using two ports, hence still a 
>> panel-lvds.
>>
>> If you're doing this to clearly distinguish, for human readability 
>> purposes,
>> single-link vs dual-link panels, I think that this would still be 
>> clear even
>> if we use panel-lvds alone because dual-link panels, as you wrote in this
>> binding, does *require* two ports, with "dual-lvds-{odd,even}-pixels" 
>> properties.
> 
> Yes, while they are both LVDS based panels the extra LVDS sink in these
> panels, and the capability to decode and display the 2 sets of signals
> are enough hardware differences that warrant for an addition of a new
> compatible.
> 
>>
>> So... the devicetree node would look like this:
>>
>> panel {
>>      compatible = "vendor,panel", "panel-lvds";
>>      ....
>>      ports {
>>          port@0 {
>>              .....
>>              -> dual-lvds-odd-pixels <-
>>          }
>>
>>          port@1 {
>>              .....
>>              -> dual-lvds-even-pixels <-
>>          };
>>      };
>> };
>>
>>> +          - required: [dual-lvds-even-pixels]
>>
>> ...Though, if you expect dual-lvds panels to get other quirks in the 
>> future,
>> that's a whole different story and you may actually need the 
>> panel-dual-lvds
>> compatible.
> 
> Yes, exactly. Even while being non-smart, there are going to be more
> quirks in future. And it would be better if they have their own
> compatible/binding, and are not getting appended in an ever-growing
> if-else ladder. :)

I can imagine a panel which you can use with a single LVDS link if the 
clock is high enough, or two LVDS links if the clock has to be lower. Is 
that a dual-lvds panel? =)

But probably that situation is no different than a panel that can work 
with DSI or DPI input.

Still, I'm agree with Angelo in that a new compatible string for dual 
link lvds feels a bit odd. That said, it's possible the panel-lvds 
bindings might get rather confusing. So I don't have a strong feeling here.

  Tomi
  

Hi Tomi,

Thank you for taking a look at the patches!

On 17-Jan-23 18:08, Tomi Valkeinen wrote:
> On 09/01/2023 18:21, Aradhya Bhatia wrote:
>> Hi Angelo,
>>
>> Thanks for taking a look at the patches!
>>
>> On 03-Jan-23 17:21, AngeloGioacchino Del Regno wrote:
>>> Il 03/01/23 07:46, Aradhya Bhatia ha scritto:
>>>> Dual-link LVDS interfaces have 2 links, with even pixels traveling on
>>>> one link, and odd pixels on the other. These panels are also generic in
>>>> nature, with no documented constraints, much like their single-link
>>>> counterparts, "panel-lvds".
>>>>
>>>> Add a new compatible, "panel-dual-lvds", and a dt-binding document for
>>>> these panels.
>>>>
>>>> Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
>>>> ---
>>>>   .../display/panel/panel-dual-lvds.yaml        | 157 
>>>> ++++++++++++++++++
>>>>   MAINTAINERS                                   |   1 +
>>>>   2 files changed, 158 insertions(+)
>>>>   create mode 100644 
>>>> Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>>>>
>>>> diff --git 
>>>> a/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>>>> new file mode 100644
>>>> index 000000000000..88a7aa2410be
>>>> --- /dev/null
>>>> +++ 
>>>> b/Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml
>>>> @@ -0,0 +1,157 @@
>>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>>> +%YAML 1.2
>>>> +---
>>>> +$id: http://devicetree.org/schemas/display/panel/panel-dual-lvds.yaml#
>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>> +
>>>> +title: Generic Dual-Link LVDS Display Panel
>>>> +
>>>> +maintainers:
>>>> +  - Aradhya Bhatia <a-bhatia1@ti.com>
>>>> +  - Thierry Reding <thierry.reding@gmail.com>
>>>> +
>>>> +description: |
>>>> +  A dual-LVDS interface is a dual-link connection with the even pixels
>>>> +  traveling on one link, and the odd pixels traveling on the other.
>>>> +
>>>> +allOf:
>>>> +  - $ref: panel-common.yaml#
>>>> +  - $ref: /schemas/display/lvds.yaml/#
>>>> +
>>>> +properties:
>>>> +  compatible:
>>>> +    oneOf:
>>>> +      - items:
>>>> +          - enum:
>>>> +              - lincolntech,lcd185-101ct
>>>> +              - microtips,13-101hieb0hf0-s
>>>> +          - const: panel-dual-lvds
>>>> +      - const: panel-dual-lvds
>>>> +
>>>> +  ports:
>>>> +    $ref: /schemas/graph.yaml#/properties/ports
>>>> +
>>>> +    properties:
>>>> +      port@0:
>>>> +        $ref: /schemas/graph.yaml#/$defs/port-base
>>>> +        unevaluatedProperties: false
>>>> +        description: The sink for first set of LVDS pixels.
>>>> +
>>>> +        properties:
>>>> +          dual-lvds-odd-pixels:
>>>> +            type: boolean
>>>> +
>>>> +          dual-lvds-even-pixels:
>>>> +            type: boolean
>>>> +
>>>> +        oneOf:
>>>> +          - required: [dual-lvds-odd-pixels]
>>>
>>> One question: why do we need a "panel-dual-lvds" compatible?
>>> A Dual-LVDS panel is a LVDS panel using two ports, hence still a 
>>> panel-lvds.
>>>
>>> If you're doing this to clearly distinguish, for human readability purposes,
>>> single-link vs dual-link panels, I think that this would still be clear even
>>> if we use panel-lvds alone because dual-link panels, as you wrote in this
>>> binding, does *require* two ports, with "dual-lvds-{odd,even}-pixels" properties.
>>
>> Yes, while they are both LVDS based panels the extra LVDS sink in these
>> panels, and the capability to decode and display the 2 sets of signals
>> are enough hardware differences that warrant for an addition of a new
>> compatible.
>>
>>>
>>> So... the devicetree node would look like this:
>>>
>>> panel {
>>>      compatible = "vendor,panel", "panel-lvds";
>>>      ....
>>>      ports {
>>>          port@0 {
>>>              .....
>>>              -> dual-lvds-odd-pixels <-
>>>          }
>>>
>>>          port@1 {
>>>              .....
>>>              -> dual-lvds-even-pixels <-
>>>          };
>>>      };
>>> };
>>>
>>>> +          - required: [dual-lvds-even-pixels]
>>>
>>> ...Though, if you expect dual-lvds panels to get other quirks in the future,
>>> that's a whole different story and you may actually need the panel-dual-lvds
>>> compatible.
>>
>> Yes, exactly. Even while being non-smart, there are going to be more
>> quirks in future. And it would be better if they have their own
>> compatible/binding, and are not getting appended in an ever-growing
>> if-else ladder. :)
> 
> I can imagine a panel which you can use with a single LVDS link if the 
> clock is high enough, or two LVDS links if the clock has to be lower. Is 
> that a dual-lvds panel? =)

Hmm, I can see what you are saying here.

If one wants to run a dual-link panel, with 1 link (given enough clock
frequency), then the bindings here will *not* allow for a single port
with the odd/even properties absent.

In such a case, the compatible will indeed need to be changed to
"panel-lvds".

While it does feel a tad bit odd, I believe it is still worth
maintaining the clarity and HW differences between the single and dual
link panels. :)

> 
> But probably that situation is no different than a panel that can work 
> with DSI or DPI input.
> 
> Still, I'm agree with Angelo in that a new compatible string for dual 
> link lvds feels a bit odd. That said, it's possible the panel-lvds  > bindings might get rather confusing. So I don't have a strong feeling 
here.

Regards
Aradhya