linux-kernel - Re: [PATCH 3/5] dt-bindings: i2c: maxim,max96717: add new properties

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Message-ID: <094bfb612d8895d2316d01704d37c853f8f86ae6.camel@collabora.com>
Date: Tue, 18 Feb 2025 14:54:07 +0100
From: Julien Massot <julien.massot@...labora.com>
To: Laurentiu Palcu <laurentiu.palcu@....nxp.com>, Mauro Carvalho Chehab
	 <mchehab@...nel.org>, Rob Herring <robh@...nel.org>, Krzysztof Kozlowski
	 <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>
Cc: devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-media@...r.kernel.org
Subject: Re: [PATCH 3/5] dt-bindings: i2c: maxim,max96717: add new properties

Hi Laurentiu,

Thanks for your patch

On Fri, 2025-02-07 at 13:29 +0200, Laurentiu Palcu wrote:
> Add 'maxim,override-mode' property to allow the user to toggle the pin
> configured chip operation mode and 'maxim,fsync-config' to configure the
> chip for relaying a frame synchronization signal, received from
> deserializer, to the attached sensor. The latter is needed for
> synchronizing the images in multi-sensor setups.
> 
> Signed-off-by: Laurentiu Palcu <laurentiu.palcu@....nxp.com>
> ---
>  .../bindings/media/i2c/maxim,max96717.yaml    | 28 +++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/media/i2c/maxim,max96717.yaml
> b/Documentation/devicetree/bindings/media/i2c/maxim,max96717.yaml
> index d1e8ba6e368ec..fae578d55fd4d 100644
> --- a/Documentation/devicetree/bindings/media/i2c/maxim,max96717.yaml
> +++ b/Documentation/devicetree/bindings/media/i2c/maxim,max96717.yaml
> @@ -42,10 +42,35 @@ properties:
>        number must be in range of [0, 10].
>  
>    gpio-controller: true
> +  gpio-reserved-ranges: true
>  
>    '#clock-cells':
>      const: 0
>  
> +  maxim,override-mode:
> +    description: Toggle the operation mode from the pin configured one.
> +    type: boolean
I understand that this property is intended to flip the GMSL link mode between
pixel and tunnel mode.
What about adding a property 'maxim,tunnel-mode' to the GMSL 'port@1'.
Here the MAX96717 only have one GMSL port but other devices, such as MAX96724 can
have 2 GMSL link and may have each link in different mode.

> 
> +
> +  maxim,fsync-config:
> +    description:
> +      Frame synchronization (FSYNC) is used to align images sent from multiple
> +      sources in surround-view applications and is required for concatenation.
> +      In FSYNC mode, the deserializer sends a sync signal to each serializer;
> +      the serializers then send the signal to the connected sensor.
> +    $ref: /schemas/types.yaml#/definitions/uint32-array
> +    items:
> +      - description: FSYNC RX ID, needs to match the TX ID configured in the deserializer.
> +        minimum: 0
> +        maximum: 31
> +        default: 0
> +      - description:
> +          Output GPIO pin used for sending the FSYNC to the sensor. The pin, however, needs
> +          to be excluded from the gpiochip using the gpio-reserved-ranges property since
> +          it will be used exclusively for FSYNC generation.
> +        minimum: 0
> +        maximum: 10
> +        default: 0
> +

MAX96717 do not have any knowledge of the frame synchronisation, but this device can forward some
GPIO to/from the deserializer.

GPIO forwarding need some information 
- The local GPIO number
- The forwarding direction Rx, Tx, Bi-directionnal
- The GPIO ID on the GMSL link (RX_ID/TX_ID)

Can we add a maxim,forward-gpio property reflecting that instead ?

>    reg:
>      maxItems: 1
>  
> @@ -113,6 +138,9 @@ examples:
>              #gpio-cells = <2>;
>              #clock-cells = <0>;
>  
> +            gpio-reserved-ranges = <0 1>;
> +            maxim,fsync-config = <0 0>;
> +
>              ports {
>                  #address-cells = <1>;
>                  #size-cells = <0>;

Regards,
-- 
Julien