linux-kernel - Re: [PATCH v2 07/66] dt-bindings: media: sun6i-a31-csi: Add MIPI CSI-2 input port

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Message-ID: <YgFCuaf007wd8sJy@pendragon.ideasonboard.com>
Date:   Mon, 7 Feb 2022 18:03:05 +0200
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Paul Kocialkowski <paul.kocialkowski@...tlin.com>
Cc:     linux-media@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
        linux-kernel@...r.kernel.org, linux-phy@...ts.infradead.org,
        linux-clk@...r.kernel.org, linux-staging@...ts.linux.dev,
        Yong Deng <yong.deng@...ewell.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Maxime Ripard <mripard@...nel.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Hans Verkuil <hans.verkuil@...co.com>,
        Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Helen Koike <helen.koike@...labora.com>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Rob Herring <robh@...nel.org>
Subject: Re: [PATCH v2 07/66] dt-bindings: media: sun6i-a31-csi: Add MIPI
 CSI-2 input port

Hi Paul,

Thank you for the patch.

On Sat, Feb 05, 2022 at 07:53:30PM +0100, Paul Kocialkowski wrote:
> The A31 CSI controller supports two distinct input interfaces:
> parallel and an external MIPI CSI-2 bridge. The parallel interface
> is often connected to a set of hardware pins while the MIPI CSI-2
> bridge is an internal FIFO-ish link. As a result, these two inputs
> are distinguished as two different ports.
> 
> Note that only one of the two may be present on a controller instance.
> For example, the V3s has one controller dedicated to MIPI-CSI2 and one
> dedicated to parallel.

Is it that only one of the two is present, or only one of the two is
connected ? In the latter case I'd make both ports required, but with
only one of them connected.

> Update the binding with an explicit ports node that holds two distinct
> port nodes: one for parallel input and one for MIPI CSI-2.
> 
> This is backward-compatible with the single-port approach that was
> previously taken for representing the parallel interface port, which
> stays enumerated as fwnode port 0.
> 
> Note that additional ports may be added in the future, especially to
> support feeding the CSI controller's output to the ISP.
> 
> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@...tlin.com>
> Reviewed-by: Rob Herring <robh@...nel.org>
> Acked-by: Maxime Ripard <mripard@...nel.org>
> ---
>  .../media/allwinner,sun6i-a31-csi.yaml        | 60 +++++++++++++++----
>  1 file changed, 47 insertions(+), 13 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/media/allwinner,sun6i-a31-csi.yaml b/Documentation/devicetree/bindings/media/allwinner,sun6i-a31-csi.yaml
> index 8b568072a069..3cc61866ea89 100644
> --- a/Documentation/devicetree/bindings/media/allwinner,sun6i-a31-csi.yaml
> +++ b/Documentation/devicetree/bindings/media/allwinner,sun6i-a31-csi.yaml
> @@ -61,6 +61,34 @@ properties:
>  
>      additionalProperties: false
>  
> +  ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +
> +    properties:
> +      port@0:
> +        $ref: "#/properties/port"
> +        unevaluatedProperties: false
> +
> +      port@1:
> +        $ref: /schemas/graph.yaml#/$defs/port-base
> +        description: MIPI CSI-2 bridge input port
> +
> +        properties:
> +          reg:
> +            const: 1
> +
> +          endpoint:
> +            $ref: video-interfaces.yaml#
> +            unevaluatedProperties: false
> +
> +        additionalProperties: false
> +
> +    anyOf:
> +      - required:
> +        - port@0
> +      - required:
> +        - port@1
> +
>  required:
>    - compatible
>    - reg

Shouldn't you specify that either port or ports is required, but not
both ? I'd also add a comment in the port node to tell it's deprecated,
and that ports should be used instead.

> @@ -89,19 +117,25 @@ examples:
>                        "ram";
>          resets = <&ccu RST_BUS_CSI>;
>  
> -        port {
> -            /* Parallel bus endpoint */
> -            csi1_ep: endpoint {
> -                remote-endpoint = <&adv7611_ep>;
> -                bus-width = <16>;
> -
> -                /*
> -                 * If hsync-active/vsync-active are missing,
> -                 * embedded BT.656 sync is used.
> -                 */
> -                 hsync-active = <0>; /* Active low */
> -                 vsync-active = <0>; /* Active low */
> -                 pclk-sample = <1>;  /* Rising */
> +        ports {
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +
> +            port@0 {
> +                reg = <0>;
> +                /* Parallel bus endpoint */
> +                csi1_ep: endpoint {
> +                    remote-endpoint = <&adv7611_ep>;
> +                    bus-width = <16>;
> +
> +                    /*
> +                     * If hsync-active/vsync-active are missing,
> +                     * embedded BT.656 sync is used.
> +                     */
> +                     hsync-active = <0>; /* Active low */
> +                     vsync-active = <0>; /* Active low */
> +                     pclk-sample = <1>;  /* Rising */

Wrong indentation.

> +                };
>              };
>          };
>      };

-- 
Regards,

Laurent Pinchart