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Date:   Mon, 17 Jan 2022 09:11:10 +0100
From:   Jacopo Mondi <jacopo@jmondi.org>
To:     Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Cc:     Niklas =?utf-8?Q?S=C3=B6derlund?= <niklas.soderlund@ragnatech.se>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Prabhakar <prabhakar.csengg@gmail.com>,
        Biju Das <biju.das.jz@bp.renesas.com>,
        linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] media: dt-bindings: media: renesas,csi2: Update
 data-lanes property
Message-ID: <20220117081110.bkwr3ttoexgr2wjt@uno.localdomain>
References: <20220113103215.27080-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
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In-Reply-To: <20220113103215.27080-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
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Hello Prabhakar,

On Thu, Jan 13, 2022 at 10:32:14AM +0000, Lad Prabhakar wrote:
> CSI-2 (CSI4LNK0) on R-Car and RZ/G2 supports 4-lane mode which is already
> handled by rcar-csi2.c driver. This patch updates the data-lanes property
> to describe the same.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
>  .../devicetree/bindings/media/renesas,csi2.yaml          | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/media/renesas,csi2.yaml b/Documentation/devicetree/bindings/media/renesas,csi2.yaml
> index e6a036721082..064a0a4c5737 100644
> --- a/Documentation/devicetree/bindings/media/renesas,csi2.yaml
> +++ b/Documentation/devicetree/bindings/media/renesas,csi2.yaml
> @@ -67,7 +67,14 @@ properties:
>                  maxItems: 1
>
>                data-lanes:
> -                maxItems: 1
> +                items:
> +                  minItems: 1
> +                  maxItems: 4
> +                  items:
> +                    - const: 1
> +                    - const: 2
> +                    - const: 3
> +                    - const: 4

Seeing "maxItems: 1" there confuses me too, as the property is an
array of data-lanes, but I'm afraid your change does not what you
intend as it would allow you to specify the number of data lanes as an
integer rather than as an array.

I think it would probably be correct to set

                data-lanes: true

(maybe maxItems: 1 is correct already)

And restrict the number of valid combinations in the board DTS file
with a construct like:

    data-lanes:
      oneOf:
        - items:
            - const: 1
            - const: 2
            - const: 3
            - const: 4
        - items:
            - const: 1
            - const: 2

Thanks
   j

>
>              required:
>                - clock-lanes
> --
> 2.17.1
>