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Date:   Thu, 4 Jun 2020 10:29:52 +0300
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Vinod Koul <vkoul@kernel.org>
Cc:     Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@linux.ie>,
        Rob Clark <robdclark@gmail.com>, linux-arm-msm@vger.kernel.org,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Andrzej Hajda <a.hajda@samsung.com>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej Skrabec <jernej.skrabec@siol.net>,
        Rob Herring <robh+dt@kernel.org>, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 2/3] dt-bindings: display: bridge: Add documentation for
 LT9611
Message-ID: <20200604072952.GA5828@pendragon.ideasonboard.com>
References: <20200513100533.42996-1-vkoul@kernel.org>
 <20200513100533.42996-3-vkoul@kernel.org>
 <20200528014837.GD4670@pendragon.ideasonboard.com>
 <20200604071859.GD3521@vkoul-mobl>
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Hi Vinod,

On Thu, Jun 04, 2020 at 12:48:59PM +0530, Vinod Koul wrote:
> Hi Laurent,
> 
> Sorry for late reply, I was out last week.

No worries.

> On 28-05-20, 04:48, Laurent Pinchart wrote:
> > > +
> > > +  interrupts:
> > > +    maxItems: 1
> > > +    description: interrupt line for the chip
> > 
> > I think you could drop the descriptions for the reg and interrupt
> > properties, they don't add much.
> 
> Sure, will do
> 
> > > +  reset-gpios:
> > > +    maxItems: 1
> > > +    description: GPIO connected to active high RESET pin.
> > > +
> > > +  vdd-supply:
> > > +    description: Regulator for 1.8V MIPI phy power.
> > > +
> > > +  vcc-supply:
> > > +    description: Regulator for 3.3V IO power.
> > > +
> > > +  ports:
> > > +    type: object
> > > +
> > > +    properties:
> > > +      "#address-cells":
> > > +        const: 1
> > > +
> > > +      "#size-cells":
> > > +        const: 0
> > > +
> > > +      port@0:
> > > +        type: object
> > > +        additionalProperties: false
> > > +
> > > +        description: |
> > > +          HDMI port for HDMI output
> > 
> > The usual practice is to have the input ports first, followed by the
> > output ports. Is there a reason not to follow that rule ?
> 
> I was not aware of this rule, is it documented somewhere?
> Nevertheless will update..

I don't think it's documented, no. It's just a common practice.

> > > +
> > > +        properties:
> > > +          reg:
> > > +            const: 0
> > > +
> > > +        patternProperties:
> > > +          endpoint:
> > 
> > If you want to use patternProperties, this should be
> > 
> >           "^endpoint@[0-9]+$":
> > 
> > (including the quotes). Same below.
> 
> Ok
> 
> > > +            type: object
> > > +            additionalProperties: false
> > > +
> > > +            properties:
> > > +              remote-endpoint: true
> > 
> > How about
> > 
> >               remote-endpoint:
> >                 $ref: /schemas/types.yaml#/definitions/phandle
> > 
> > and the same below ?
> 
> Ok
> 
> > You also need a reg property if multiple endpoints are present.
> 
> Will update
>
> > > +
> > > +        required:
> > > +          - reg
> > > +
> > > +      port@1:
> > > +        type: object
> > > +        additionalProperties: false
> > > +
> > > +        description: |
> > > +          MIPI port-1 for MIPI input
> > > +
> > > +        properties:
> > > +          reg:
> > > +            const: 1
> > > +
> > > +        patternProperties:
> > > +          endpoint:
> > > +            type: object
> > > +            additionalProperties: false
> > > +
> > > +            properties:
> > > +              remote-endpoint: true
> > > +
> > > +        required:
> > > +          - reg
> > > +
> > > +      port@2:
> > > +        type: object
> > > +        additionalProperties: false
> > > +
> > > +        description: |
> > > +          MIPI port-2 for MIPI input
> > 
> > A description of how the two MIPI inputs differ would be useful. In
> > particular, are both mandatory, or is it valid to connect only one of
> > the two ? If using a single input is supported, can it be either, or
> > does it have to be the first one ? When using both inputs, what should
> > be connected to them ?
> 
> Sure I will add details. port-1 is mandatory and port-2 optional. port-2
> is used in combination with port-1 to drive displays for higher
> resolution like 4k
> 
> > > +
> > > +        properties:
> > > +          reg:
> > > +            const: 2
> > > +
> > > +        patternProperties:
> > > +          endpoint:
> > > +            type: object
> > > +            additionalProperties: false
> > > +
> > > +            properties:
> > > +              remote-endpoint: true
> > > +
> > > +        required:
> > > +          - reg
> > > +
> > > +    required:
> > > +      - "#address-cells"
> > > +      - "#size-cells"
> > > +      - port@0
> > > +      - port@1
> > > +
> > > +required:
> > > +  - compatible
> > > +  - reg
> > > +  - interrupts
> > > +  - vdd-supply
> > > +  - vcc-supply
> > > +  - ports
> > > +
> > > +additionalProperties: false
> > > +
> > > +examples:
> > > +  - |
> > > +    #include <dt-bindings/gpio/gpio.h>
> > > +    #include <dt-bindings/interrupt-controller/irq.h>
> > > +
> > > +    i2c10 {
> > > +      #address-cells = <1>;
> > > +      #size-cells = <0>;
> > > +
> > > +      lt9611_codec: hdmi-bridge@3b {
> > 
> > Please drop unused labels.
> 
> ok
> 
> > > +        compatible = "lontium,lt9611";
> > > +        reg = <0x3b>;
> > > +
> > > +        reset-gpios = <&tlmm 128 GPIO_ACTIVE_HIGH>;
> > > +        interrupts-extended = <&tlmm 84 IRQ_TYPE_EDGE_FALLING>;
> > > +
> > > +        vdd-supply = <&lt9611_1v8>;
> > > +        vcc-supply = <&lt9611_3v3>;
> > > +
> > > +        ports {
> > > +          #address-cells = <1>;
> > > +          #size-cells = <0>;
> > > +
> > > +          port@0 {
> > > +            reg = <0>;
> > > +            lt9611_out: endpoint {
> > > +              remote-endpoint = <&hdmi_con>;
> > > +            };
> > > +          };
> > > +
> > > +          port@1 {
> > > +            reg = <1>;
> > > +            lt9611_a: endpoint {
> > > +              remote-endpoint = <&dsi0_out>;
> > > +            };
> > > +          };
> > > +
> > > +          port@2 {
> > > +            reg = <2>;
> > > +            lt9611_b: endpoint {
> > > +              remote-endpoint = <&dsi1_out>;
> > > +            };
> > > +          };
> > > +        };
> > > +      };
> > > +    };
> > 
> > It's customary to end YAML schema files with ... on a separate line.
> 
> Will update
> 
> Thanks for the review

-- 
Regards,

Laurent Pinchart