RE: [PATCH v2 2/4] dt-bindings: display: bridge: Repurpose lvds-encoder

[Fabrizio Castro <fabrizio.castro@xxxxxxxxxxxxxx>]

Hello Rob,

Thank you for your feedback!

> From: Rob Herring <robh+dt@xxxxxxxxxx>
> Sent: 04 November 2019 21:23
> Subject: Re: [PATCH v2 2/4] dt-bindings: display: bridge: Repurpose lvds-encoder
> 
> On Mon, Nov 4, 2019 at 10:58 AM Fabrizio Castro
> <fabrizio.castro@xxxxxxxxxxxxxx> wrote:
> >
> > In an effort to repurpose lvds-encoder.c to also serve the
> > function of LVDS decoders, we ended up defining a new "generic"
> > compatible string, therefore adapt the dt-bindings to fit the
> > new purpose. Also, convert the dt-bindings from .txt to .yaml
> > while at it.
> 
> "Also, ... while at it." is a sign for split into 2 patches.

Will split into 2 patches

> 
> > Signed-off-by: Fabrizio Castro <fabrizio.castro@xxxxxxxxxxxxxx>
> >
> > ---
> > v1->v2:
> > * Converted to dt-schema as per Neil's comment
> > ---
> >  .../bindings/display/bridge/lvds-codec.yaml        | 117 +++++++++++++++++++++
> >  .../bindings/display/bridge/lvds-transmitter.txt   |  66 ------------
> >  2 files changed, 117 insertions(+), 66 deletions(-)
> >  create mode 100644 Documentation/devicetree/bindings/display/bridge/lvds-codec.yaml
> >  delete mode 100644 Documentation/devicetree/bindings/display/bridge/lvds-transmitter.txt
> >
> > diff --git a/Documentation/devicetree/bindings/display/bridge/lvds-codec.yaml
> b/Documentation/devicetree/bindings/display/bridge/lvds-codec.yaml
> > new file mode 100644
> > index 0000000..ff79bc2
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/display/bridge/lvds-codec.yaml
> > @@ -0,0 +1,117 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/display/bridge/lvds-codec.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Trasnparent LVDS encoders and LVDS decoders
> 
> Typo

Will fix

> 
> > +
> > +maintainers:
> > +  - Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
> > +
> > +description: |
> > +  This binding supports transparent LVDS encoders and LVDS decoders that don't
> > +  require any configuration.
> > +
> > +  LVDS is a physical layer specification defined in ANSI/TIA/EIA-644-A. Multiple
> > +  incompatible data link layers have been used over time to transmit image data
> > +  to LVDS panels. This binding targets devices compatible with the following
> > +  specifications only.
> > +
> > +  [JEIDA] "Digital Interface Standards for Monitor", JEIDA-59-1999, February
> > +  1999 (Version 1.0), Japan Electronic Industry Development Association (JEIDA)
> > +  [LDI] "Open LVDS Display Interface", May 1999 (Version 0.95), National
> > +  Semiconductor
> > +  [VESA] "VESA Notebook Panel Standard", October 2007 (Version 1.0), Video
> > +  Electronics Standards Association (VESA)
> > +
> > +  Those devices have been marketed under the FPD-Link and FlatLink brand names
> > +  among others.
> > +
> > +properties:
> > +  compatible:
> > +    description: |
> > +      Any encoder or decoder compatible with this generic binding, but with
> > +      additional properties not listed here, must define its own binding and
> > +      list a device specific compatible first followed by the generic compatible
> > +    items:
> > +      - enum:
> 
> You can drop 'items' when there's only 1.

Will drop

> 
> > +        - lvds-encoder # for LVDS encoders
> > +        - lvds-decoder # for LVDS decoders
> > +
> > +  ports:
> > +    type: object
> > +    description: |
> > +      This device has two video ports. Their connections are modeled using the
> > +      OF graph bindings specified in Documentation/devicetree/bindings/graph.txt
> > +    properties:
> > +      port@0:
> > +        type: object
> > +        description: |
> > +          With LVDS encoders port 0 is for parallel input
> > +          With LVDS decoders port 0 is for LVDS input
> > +
> > +      port@1:
> > +        type: object
> > +        description: |
> > +          With LVDS encoders port 1 is for LVDS output
> > +          With LVDS decoders port 1 is for parallel output
> 
> port@* are required, right?

Yes, port@0 and port@1 are both required, similarly to:
Documentation/devicetree/bindings/display/st,stm32-dsi.yaml
therefore I have put "ports" under "required", in a similar fashion.
What's the right way of specifying this?

Thanks,
Fab

> 
> > +
> > +required:
> > +  - compatible
> > +  - ports
> > +
> > +examples:
> > +  - |
> > +    lvds-encoder {
> > +      compatible = "lvds-encoder";
> > +
> > +      ports {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        port@0 {
> > +          reg = <0>;
> > +
> > +          lvds_enc_in: endpoint {
> > +            remote-endpoint = <&display_out_rgb>;
> > +          };
> > +        };
> > +
> > +        port@1 {
> > +          reg = <1>;
> > +
> > +          lvds_enc_out: endpoint {
> > +            remote-endpoint = <&lvds_panel_in>;
> > +          };
> > +        };
> > +      };
> > +    };
> > +
> > +  - |
> > +    lvds-decoder {
> > +      compatible = "lvds-decoder";
> > +
> > +      ports {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        port@0 {
> > +          reg = <0>;
> > +
> > +          lvds_dec_in: endpoint {
> > +            remote-endpoint = <&display_out_lvds>;
> > +          };
> > +        };
> > +
> > +        port@1 {
> > +          reg = <1>;
> > +
> > +          lvds_dec_out: endpoint {
> > +            remote-endpoint = <&rgb_panel_in>;
> > +          };
> > +        };
> > +      };
> > +    };
> > +
> > +...