Re: [PATCH v5 4/8] dt-bindings: media: add bindings for TI DS90UB953

[Tomi Valkeinen]

On 11/12/2022 19:34, Laurent Pinchart wrote:
> Hi Tomi,
>
> Thank you for the patch.
>
> On Thu, Dec 08, 2022 at 12:40:02PM +0200, Tomi Valkeinen wrote:
> > Add DT bindings for TI DS90UB953 FPDLink-3 Serializer.
> >
> > Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
> > ---
> >   .../bindings/media/i2c/ti,ds90ub953.yaml      | 112 ++++++++++++++++++
> >   1 file changed, 112 insertions(+)
> >   create mode 100644 Documentation/devicetree/bindings/media/i2c/ti,ds90ub953.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/media/i2c/ti,ds90ub953.yaml b/Documentation/devicetree/bindings/media/i2c/ti,ds90ub953.yaml
> > new file mode 100644
> > index 000000000000..fd7d25d93e2c
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/media/i2c/ti,ds90ub953.yaml
> > @@ -0,0 +1,112 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/media/i2c/ti,ds90ub953.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Texas Instruments DS90UB953 FPD-Link 3 Serializer
> > +
> > +maintainers:
> > +  - Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
> > +
> > +description:
> > +  The TI DS90UB953 is an FPD-Link 3 video serializer for MIPI CSI-2.
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - ti,ds90ub953-q1
> > +      - ti,ds90ub971-q1
> > +
> > +  '#gpio-cells':
> > +    const: 2
>
> I would add a description here, to tell what the cells correspond to. In
> particular, the first cell selects the GPIO_* pin number, it would be
> nice to document that its value should be in the range [0, 3].
>
> Same comment for patch 3/8 (DS90UB913 bindings). There you could also
> mention that GPO2 and the output clock are mutually exclusive.

Yep. I have added this for ub913:
      First cell is the GPO pin number, second cell is the flags. The 
GPO pin
      number must be in range of [0, 3]. Note that GPOs 2 and 3 are not
      available in external oscillator mode.

and this for ub953:
      First cell is the GPIO pin number, second cell is the flags. The 
GPIO pin
      number must be in range of [0, 3].

> > +
> > +  gpio-controller: true
> > +
>
> No need for clocks and clock-names for the reference input clock ? Or is
> this because you support sync mode only for now ?

Right, I don't have the clock on my hw, but it's probably better to add 
it to the binding already.

> > +  '#clock-cells':
> > +    const: 0
> > +
> > +  ports:
> > +    $ref: /schemas/graph.yaml#/properties/ports
> > +
> > +    properties:
> > +      port@0:
> > +        $ref: /schemas/graph.yaml#/$defs/port-base
> > +        unevaluatedProperties: false
> > +        description: CSI-2 input port
> > +
> > +        properties:
> > +          endpoint:
> > +            $ref: /schemas/media/video-interfaces.yaml#
> > +            unevaluatedProperties: false
>
> Should the data-lanes property be required for the CSI-2 input ?

Yes.

> > +
> > +      port@1:
> > +        $ref: /schemas/graph.yaml#/properties/port
> > +        unevaluatedProperties: false
> > +        description: FPD-Link 3 output port
> > +
> > +  i2c:
> > +    $ref: /schemas/i2c/i2c-controller.yaml#
> > +    unevaluatedProperties: false
> > +
> > +required:
> > +  - compatible
> > +  - '#gpio-cells'
> > +  - gpio-controller
> > +  - '#clock-cells'
> > +  - ports
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    #include <dt-bindings/gpio/gpio.h>
> > +
> > +    serializer {
> > +      compatible = "ti,ds90ub953-q1";
> > +
> > +      gpio-controller;
> > +      #gpio-cells = <2>;
> > +
> > +      #clock-cells = <0>;
> > +
> > +      ports {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        port@0 {
> > +          reg = <0>;
> > +          ub953_in: endpoint {
> > +            clock-lanes = <0>;
> > +            data-lanes = <1 2 3 4>;
> > +            remote-endpoint = <&sensor_out>;
> > +          };
> > +        };
> > +
> > +        port@1 {
> > +          reg = <1>;
> > +          endpoint {
> > +            remote-endpoint = <&deser_fpd_in>;
> > +          };
> > +        };
> > +      };
> > +
> > +      i2c {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        sensor@1a {
> > +          compatible = "sony,imx274";
> > +          reg = <0x1a>;
> > +
> > +          reset-gpios = <&serializer 0 GPIO_ACTIVE_LOW>;
>
> Maybe add
>
>            clocks = <&serializer>;
> 	  clock-names = "inck";
>
> to showcase the clock connection ?

Yes, that's a good idea.

 Tomi