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References: <20221019093215.8204-1-allen.chen@ite.com.tw> <20221019093215.8204-2-allen.chen@ite.com.tw>
 <20221024163748.GA1874793-robh@kernel.org>
In-Reply-To: <20221024163748.GA1874793-robh@kernel.org>
From:   Pin-yen Lin <treapking@chromium.org>
Date:   Wed, 26 Oct 2022 12:03:02 +0800
Message-ID: <CAEXTbpfpmAAaXOEkirMtuSJLopv-Us6w-46oE+GSxXiMGU-ZfQ@mail.gmail.com>
Subject: Re: [PATCH v5 1/2] dt-bindings: it6505: add properties to restrict
 output bandwidth
To:     allen <allen.chen@ite.com.tw>
Cc:     Jau-Chih Tseng <Jau-Chih.Tseng@ite.com.tw>,
        Hermes Wu <Hermes.Wu@ite.com.tw>,
        Kenneth Hung <Kenneth.Hung@ite.com.tw>,
        Andrzej Hajda <andrzej.hajda@intel.com>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Robert Foss <robert.foss@linaro.org>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        "open list:DRM DRIVERS" <dri-devel@lists.freedesktop.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>,
        Rob Herring <robh@kernel.org>
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Hi Allen,

On Tue, Oct 25, 2022 at 12:37 AM Rob Herring <robh@kernel.org> wrote:
>
> On Wed, Oct 19, 2022 at 05:32:13PM +0800, allen wrote:
> > From: allen chen <allen.chen@ite.com.tw>
> >
> > Add properties to restrict dp output data-lanes and clock.
> >
> > Signed-off-by: Pin-Yen Lin <treapking@chromium.org>
> > Signed-off-by: Allen Chen <allen.chen@ite.com.tw>
> > ---
> >  .../bindings/display/bridge/ite,it6505.yaml   | 89 +++++++++++++++++--
> >  1 file changed, 83 insertions(+), 6 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml b/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
> > index 833d11b2303a7..8e607b6929fc9 100644
> > --- a/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
> > +++ b/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
> > @@ -52,9 +52,70 @@ properties:
> >      maxItems: 1
> >      description: extcon specifier for the Power Delivery
> >
> > -  port:
> > -    $ref: /schemas/graph.yaml#/properties/port
> > -    description: A port node pointing to DPI host port node
>
> No existing users you are breaking? The commit msg should explain.
>
> > +  ports:
> > +    $ref: /schemas/graph.yaml#/properties/ports
> > +
> > +    properties:
> > +      port@0:
> > +        $ref: /schemas/graph.yaml#/$defs/port-base
> > +        unevaluatedProperties: false
> > +        description: A port node pointing to DPI host port node
> > +
> > +        properties:
> > +          endpoint:
> > +            $ref: /schemas/graph.yaml#/$defs/endpoint-base
> > +            unevaluatedProperties: false
> > +
> > +            properties:
> > +              link-frequencies:
> > +                minItems: 1
> > +                maxItems: 1
> > +                description: Allowed max link frequencies in Hz
> > +
> > +      port@1:
> > +        $ref: /schemas/graph.yaml#/$defs/port-base
> > +        unevaluatedProperties: false
> > +        description: Video port for DP output
> > +
> > +        properties:
> > +          endpoint:
> > +            $ref: /schemas/graph.yaml#/$defs/endpoint-base
> > +            unevaluatedProperties: false
> > +
> > +            properties:
> > +              data-lanes:
> > +                oneOf:
> > +                  - minItems: 1
> > +                    maxItems: 1
> > +                    uniqueItems: true
> > +                    items:
> > +                      enum:
> > +                        - 0
> > +                        - 1
> > +                    description: For one lane operation.
> > +
> > +                  - minItems: 2
> > +                    maxItems: 2
> > +                    uniqueItems: true
> > +                    items:
> > +                      enum:
> > +                        - 0
> > +                        - 1
> > +                    description: For two lanes operation.
> > +
> > +                  - minItems: 4
> > +                    maxItems: 4
> > +                    uniqueItems: true
> > +                    items:
> > +                      enum:
> > +                        - 0
> > +                        - 1
> > +                        - 2
> > +                        - 3
> > +                    description: For four lanes operation.
>
> I would do just:
>
> data-lanes:
>   minItems: 1
>   items:
>     - enum: [ 0, 1 ]
>     - const: 1
>     - const: 2
>     - const: 3

I believe we also want a `uniqueItems: true` to prevent duplicate
items like `<1 1>`.

Regards,
Pin-yen

>
> It does allow 3 lanes, but I don't think that's a big deal. What it does
> doesn't allow is any order and yours does.
>
> Rob