[PATCH v8 05/17] dt-bindings: media: Add bindings for ARM mali-c55

[Laurent Pinchart]

Hi Dan,

Thank you for the patch.

On Wed, Nov 06, 2024 at 10:05:22AM +0000, Daniel Scally wrote:
> Add the yaml binding for ARM's Mali-C55 Image Signal Processor.
> 
> Acked-by: Nayden Kanchev <nayden.kanchev at arm.com>
> Co-developed-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
> Signed-off-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
> Signed-off-by: Daniel Scally <dan.scally at ideasonboard.com>
> ---
> Changes in v8:
> 
> 	- Added the video clock back in. Now that we have actual hardware it's
> 	  clear that it's necessary.
> 	- Added reset lines 
> 	- Dropped R-bs
> 
> Changes in v7:
> 
> 	- None
> 
> Changes in v6:
> 
> 	- None
> 
> Changes in v5:
> 
> 	- None
> 
> Changes in v4:
> 
> 	- Switched to port instead of ports
> 
> Changes in v3:
> 
> 	- Dropped the video clock as suggested by Laurent. I didn't retain it
> 	for the purposes of the refcount since this driver will call .s_stream()
> 	for the sensor driver which will refcount the clock anyway.
> 	- Clarified that the port is a parallel input port rather (Sakari)
> 
> Changes in v2:
> 
> 	- Added clocks information
> 	- Fixed the warnings raised by Rob
> 
>  .../bindings/media/arm,mali-c55.yaml          | 82 +++++++++++++++++++
>  1 file changed, 82 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/arm,mali-c55.yaml
> 
> diff --git a/Documentation/devicetree/bindings/media/arm,mali-c55.yaml b/Documentation/devicetree/bindings/media/arm,mali-c55.yaml
> new file mode 100644
> index 000000000000..efc88fd2c447
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/arm,mali-c55.yaml
> @@ -0,0 +1,82 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/media/arm,mali-c55.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: ARM Mali-C55 Image Signal Processor
> +
> +maintainers:
> +  - Daniel Scally <dan.scally at ideasonboard.com>
> +  - Jacopo Mondi <jacopo.mondi at ideasonboard.com>
> +
> +properties:
> +  compatible:
> +    const: arm,mali-c55

I have a feeling we may need to add an SoC-specific compatible string to
support platform-specific integration quirks. Let's see if we will have
a use for that in the RZ/V2H. It can also be addressed later if needed.

> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  clocks:
> +    items:
> +      - description: ISP Video Clock
> +      - description: ISP AXI clock
> +      - description: ISP AHB-lite clock
> +
> +  clock-names:
> +    items:
> +      - const: vclk
> +      - const: aclk
> +      - const: hclk
> +
> +  resets:
> +    items:
> +      - description: vclk domain reset
> +      - description: aclk domain reset
> +      - description: hclk domain reset
> +
> +  reset-names:
> +    items:
> +      - const: vresetn
> +      - const: aresetn
> +      - const: hresetn
> +
> +  port:
> +    $ref: /schemas/graph.yaml#/properties/port
> +    description: Input parallel video bus

Doesn't the ISP have two input ports, for two exposures ? Depending on
the SoC integration, could they be connected to two different devices,
with the two connections having to be modelled in DT ? Looking at the
changelog you've switched from 'ports' to 'port' in v4, but I think we
should either have two ports right away, or be ready for a second port
later if SoC integrations requires that. That could be a good enough
reason to use 'ports' right away, even with a single port.

> +
> +    properties:
> +      endpoint:
> +        $ref: /schemas/graph.yaml#/properties/endpoint
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - clocks
> +  - clock-names
> +  - port
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    mali_c55: isp at 400000 {
> +      compatible = "arm,mali-c55";
> +      reg = <0x400000 0x200000>;
> +      clocks = <&clk 0>, <&clk 1>, <&clk 2>;
> +      clock-names = "vclk", "aclk", "hclk";
> +      resets = <&resets 0>, <&resets 1>, <&resets 2>;
> +      reset-names = "vresetn", "aresetn", "hresetn";
> +      interrupts = <0>;
> +
> +      port {
> +        isp_in: endpoint {
> +            remote-endpoint = <&csi2_rx_out>;
> +        };
> +      };
> +    };
> +...

-- 
Regards,

Laurent Pinchart