linux-kernel - Re: [PATCH v6 2/3] media: dt-bindings: media: i2c: Add bindings for TW9900

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Date:   Mon, 9 Oct 2023 05:18:38 +0300
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Mehdi Djait <mehdi.djait@...tlin.com>
Cc:     mchehab@...nel.org, heiko@...ech.de, hverkuil-cisco@...all.nl,
        krzysztof.kozlowski+dt@...aro.org, robh+dt@...nel.org,
        conor+dt@...nel.org, linux-media@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        thomas.petazzoni@...tlin.com, alexandre.belloni@...tlin.com,
        maxime.chevallier@...tlin.com, paul.kocialkowski@...tlin.com
Subject: Re: [PATCH v6 2/3] media: dt-bindings: media: i2c: Add bindings for
 TW9900

Hi Mehdi,

Thank you for the patch.

On Fri, Oct 06, 2023 at 06:25:29PM +0200, Mehdi Djait wrote:
> The Techwell TW9900 is a video decoder supporting multiple input
> standards, such as PAL and NTSC, and outputs a BT.656 video
> signal.
> 
> It's designed to be low-power, posesses some features such as a
> programmable comb-filter, and automatic input standard detection
> 
> Signed-off-by: Mehdi Djait <mehdi.djait@...tlin.com>
> ---
> V5->V6: 
> - This commit had a "Reviewed-by: Rob Herring <robh@...nel.org>" Tag but
>   decided not to collect it because the last Iteration was more than 2
>   years ago
> - removed SECAM from the mentioned standards
> - changed maintainer
> 
> V4->V5: 
> - renamed the file to match the compatible string, and referenced
>   the graph.yaml schema
> 
> V3->V4: 
> - add the missing reset-gpios node to the binding
> 
> V2->V3: 
> - fix the example not compiling due to a typo in the reset-gpios
>   node.
> 
>  .../bindings/media/i2c/techwell,tw9900.yaml   | 61 +++++++++++++++++++
>  1 file changed, 61 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/i2c/techwell,tw9900.yaml
> 
> diff --git a/Documentation/devicetree/bindings/media/i2c/techwell,tw9900.yaml b/Documentation/devicetree/bindings/media/i2c/techwell,tw9900.yaml
> new file mode 100644
> index 000000000000..24bbbff5cc01
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/i2c/techwell,tw9900.yaml
> @@ -0,0 +1,61 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/media/i2c/techwell,tw9900.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Techwell TW9900 NTSC/PAL video decoder
> +
> +maintainers:
> +  - Mehdi Djait <mehdi.djait@...tlin.com>
> +
> +description:
> +  The tw9900 is a multi-standard video decoder, supporting NTSC, PAL standards
> +  with auto-detection features.
> +
> +properties:
> +  compatible:
> +    const: techwell,tw9900
> +
> +  reg:
> +    maxItems: 1
> +
> +  vdd-supply:
> +    description: VDD power supply
> +
> +  reset-gpios:
> +    description: GPIO descriptor for the RESET input pin
> +    maxItems: 1

How about the power down GPIO ?

The chip requires a clock, which is provided by a crystal oscillator in
the block diagram I found. Does it also support an external clock ? If
so the bindings should support it, although this could be added later.

> +
> +  port:
> +    $ref: /schemas/graph.yaml#/properties/port
> +    description:
> +      Video port for the decoder output.

How about input ports, connected to nodes that model the connector(s) ?

> +
> +additionalProperties: false
> +
> +required:
> +  - compatible
> +  - reg
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +    i2c {
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +
> +            tw9900: tw9900@44 {
> +                    compatible = "techwell,tw9900";
> +                    reg = <0x44>;
> +
> +                    vdd-supply = <&tw9900_supply>;
> +                    reset-gpios = <&gpio2 5 GPIO_ACTIVE_LOW>;
> +
> +                    port {
> +                            tw9900_out: endpoint {
> +                                    remote-endpoint = <&vip_in>;
> +                            };
> +                    };
> +            };
> +    };

-- 
Regards,

Laurent Pinchart