[PATCH v12 03/15] dt-bindings: media: Add bindings for ARM mali-c55

[Lad, Prabhakar]

Hi Daniel,

Thank you for the patch.

On Thu, Oct 2, 2025 at 11:19 AM Daniel Scally
<dan.scally at ideasonboard.com> wrote:
>
> Add the yaml binding for ARM's Mali-C55 Image Signal Processor.
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski at linaro.org>
> 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 v12:
>
>         - _Actually_ dropped the arm,inline property mode, having forgotten to
>           do so in v11.
>
> Changes in v11:
>
>         - Dropped in arm,inline_mode property. This is now identical to the
>           reviewed version 8, so I have kept the tags on there.
>
> Changes in v10:
>
>         - None
>
> Changes in v9:
>
>         - Added the arm,inline_mode property to differentiate between inline and
>           memory input configurations
>
> 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
> ---
>  .../devicetree/bindings/media/arm,mali-c55.yaml    | 82 ++++++++++++++++++++++
>  1 file changed, 82 insertions(+)
>
> 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 0000000000000000000000000000000000000000..efc88fd2c447e98dd82a1fc1bae234147eb967a8
> --- /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
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  clocks:
> +    items:
> +      - description: ISP Video Clock
> +      - description: ISP AXI clock
> +      - description: ISP AHB-lite clock
As per RZ/V2H HW manual we have reg clock looking at the driver code
it does have readl. IVC has reg clock if IVC driver fails are you
still able to read/write regs from ISP driver? I think we do need to
pass reg clock too.

Also for IVC we do have a main clock (which is a system clock).  Can
you please educate me on what is the purpose of it. Just curious as we
pass to IVC and not ISP.

> +
> +  clock-names:
> +    items:
> +      - const: vclk
> +      - const: aclk
> +      - const: hclk
Not sure if we want to have the same names as IVC or vice versa.

> +
> +  resets:
> +    items:
> +      - description: vclk domain reset
> +      - description: aclk domain reset
> +      - description: hclk domain reset
Same query here, wrt register reset.

> +
> +  reset-names:
> +    items:
> +      - const: vresetn
> +      - const: aresetn
> +      - const: hresetn
ditto naming.

> +
> +  port:
> +    $ref: /schemas/graph.yaml#/properties/port
> +    description: Input parallel video bus
> +
> +    properties:
> +      endpoint:
> +        $ref: /schemas/graph.yaml#/properties/endpoint
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - clocks
> +  - clock-names
> +  - port
maybe also resets and rest-names should be part of required properties?

> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    mali_c55: isp at 400000 {
we could drop `mali_c55`

> +      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>;
I would have a non-zero val here.

Cheers,
Prabhakar

> +
> +      port {
> +        isp_in: endpoint {
> +            remote-endpoint = <&csi2_rx_out>;
> +        };
> +      };
> +    };
> +...
>
> --
> 2.43.0
>
>