Re: [PATCH v8 2/7] dt-bindings: media: max9286: Define 'maxim,gpio-poc'

[Kieran Bingham <kieran.bingham@ideasonboard.com>]

Hi Jacopo,

Quoting Jacopo Mondi (2021-12-16 16:34:34)
> Define a new vendor property in the maxim,max9286 binding schema.
> 
> The new property allows to declare that the remote camera
> power-over-coax is controlled by one of the MAX9286 gpio lines.
> 
> As it is currently not possible to establish a regulator as consumer
> of the MAX9286 gpio controller for this purpose, the property allows to
> declare that the camera power is controlled by the MAX9286 directly.
> 
> The property accepts a gpio-index (0 or 1) and one line polarity
> flag as defined by dt-bindings/gpio/gpio.h.
> 
> Reviewed-by: Rob Herring <robh@kernel.org>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> ---
>  .../bindings/media/i2c/maxim,max9286.yaml     | 67 ++++++++++++++++++-
>  1 file changed, 66 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml b/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml
> index ab4e7a620362..90315e217003 100644
> --- a/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml
> +++ b/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml
> @@ -70,6 +70,28 @@ properties:
>        a remote serializer whose high-threshold noise immunity is not enabled
>        is 100000 micro volts
>  
> +  maxim,gpio-poc:
> +    $ref: '/schemas/types.yaml#/definitions/uint32-array'
> +    minItems: 2
> +    maxItems: 2
> +    description: |
> +      Index of the MAX9286 gpio output line (0 or 1) that controls Power over
> +      Coax to the cameras and its associated polarity flag.
> +
> +      The property accepts an array of two unsigned integers, the first being
> +      the gpio line index (0 or 1) and the second being the gpio line polarity
> +      flag (GPIO_ACTIVE_HIGH or GPIO_ACTIVE_LOW) as defined in
> +      <include/dt-bindings/gpio/gpio.h>.
> +
> +      When the remote cameras power is controlled by one of the MAX9286 gpio
> +      lines, this property has to be used to specify which line among the two
> +      available ones controls the remote camera power enablement.
> +
> +      When this property is used it is not possible to register a gpio
> +      controller as the gpio lines are controlled directly by the MAX9286 and
> +      not available for consumers, nor the 'poc-supply' property should be
> +      specified.
> +
>    ports:
>      $ref: /schemas/graph.yaml#/properties/ports
>  
> @@ -165,7 +187,16 @@ required:
>    - reg
>    - ports
>    - i2c-mux
> -  - gpio-controller
> +
> +# If 'maxim,gpio-poc' is present, then 'poc-supply' and 'gpio-controller'
> +# are not allowed.
> +if:
> +  required:
> +    - maxim,gpio-poc
> +then:
> +  properties:
> +    poc-supply: false
> +    gpio-controller: false
>  
>  additionalProperties: false
>  
> @@ -310,4 +341,38 @@ examples:
>                  };
>              };
>          };
> +
> +        /*
> +        * Example of a deserializer that controls the camera Power over Coax

Indentation seems broken...

> +        * through one of its gpio lines.
> +        */
> +        gmsl-deserializer@6c {
> +            compatible = "maxim,max9286";
> +            reg = <0x6c>;
> +            enable-gpios = <&gpio 14 GPIO_ACTIVE_HIGH>;
> +
> +            /*
> +            * The remote camera power is controlled by MAX9286 GPIO line #0.
> +            * No 'poc-supply' nor 'gpio-controller' are specified.
> +            */
> +            maxim,gpio-poc = <0 GPIO_ACTIVE_LOW>;
> +
> +            /*
> +            * Do not describe connections as they're the same as in the previous

Here too,

This seems like a simple way to describe this without hitting the
circular dependency loops I was facing when I looked at this. I'm sorry
it took me until v8 to find this out ;-)

Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>

> +            * example.
> +            */
> +            ports {
> +                #address-cells = <1>;
> +                #size-cells = <0>;
> +
> +                port@4 {
> +                    reg = <4>;
> +                };
> +            };
> +
> +            i2c-mux {
> +                #address-cells = <1>;
> +                #size-cells = <0>;
> +            };
> +        };
>      };
> -- 
> 2.33.1
>