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

Add DT bindings for TI DS90UB953 FPDLink-3 Serializer.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 .../bindings/media/i2c/ti,ds90ub953.yaml      | 112 ++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/i2c/ti,ds90ub953.yaml

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@ideasonboard.com>
> ---
>  .../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@ideasonboard.com>
> +
> +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.

> +
> +  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 ?

> +  '#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 ?

> +
> +      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 ?

> +
> +          port {
> +            sensor_out: endpoint {
> +              remote-endpoint = <&ub953_in>;
> +            };
> +          };
> +        };
> +      };
> +    };
> +...

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@ideasonboard.com>
>> ---
>>   .../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@ideasonboard.com>
>> +
>> +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

Hi Rob,

On 09/12/2022 23:27, Rob Herring wrote:
> On Thu, Dec 08, 2022 at 12:40:02PM +0200, Tomi Valkeinen wrote:
>> Add DT bindings for TI DS90UB953 FPDLink-3 Serializer.
> 
> Seems like this and DS90UB913 binding could be combined. I couldn't spot
> a difference.

They are indeed quite similar, but there are a few diffs, especially 
after fixing Laurent's review comments.

E.g, as the UB913 is a parallel video serializer and the UB953 is a 
CSI-2 serializer, the input port on UB913 has 'pclk-sample' property but 
UB953 has 'data-lanes' property. The descriptions differ also a bit for 
the above mentioned difference.

The above points would still allow combining the bindings, though. But I 
feel the UB913 is somewhat a different class of serializer device 
compared to UB953 (and UB971 which the UB953's binding also supports), 
so my gut feeling says it's better to keep them separate. But I don't 
have much experience on maintaining such bindings, and, afaik, we could 
always split the bindings later if needed.

So... Do you have a preference on either way? Or maybe we can come back 
to this after I send the next version with the updates.

> In the subjects, drop 'binding for'. The prefix says this is a binding.
> Maybe add 'Serializer'.

Ok.

  Tomi