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Date:   Tue, 16 Mar 2021 00:15:16 +0200
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Jacopo Mondi <jacopo+renesas@jmondi.org>
Cc:     Geert Uytterhoeven <geert+renesas@glider.be>,
        Magnus Damm <magnus.damm@gmail.com>,
        Kieran Bingham <kieran.bingham@ideasonboard.com>,
        Rob Herring <robh+dt@kernel.org>,
        linux-renesas-soc@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/4] dt-bindings: media: max9286: Describe gpio-hog
Message-ID: <YE/cdBtSx3cDIqCY@pendragon.ideasonboard.com>
References: <20210315163028.173148-1-jacopo+renesas@jmondi.org>
 <20210315163028.173148-2-jacopo+renesas@jmondi.org>
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In-Reply-To: <20210315163028.173148-2-jacopo+renesas@jmondi.org>
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Hi Jacopo,

Thank you for the patch.

On Mon, Mar 15, 2021 at 05:30:25PM +0100, Jacopo Mondi wrote:
> The MAX9286 GMSL deserializer features gpio controller capabilities,
> as it provides 2 GPIO lines.
> 
> As establishing a regulator that uses one of the GPIO lines and
> enabling/disabling it at run-time in the max9286 won't work due to
> a circular dependency on the gpio-controller/regulator creation, allow
> the usage of a gpio-hog for that purpose.
> 
> The usage of the gpio-hog is required in designs where the MAX9286
> GPIO lines control the remote cameras power.
> 
> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>

That's really a workaround until we can find a good solution, do we have
to officially support it in the DT bindings ?

> ---
>  .../bindings/media/i2c/maxim,max9286.yaml        | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml b/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml
> index ee16102fdfe7..9038300e373c 100644
> --- a/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml
> +++ b/Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml
> @@ -177,6 +177,22 @@ properties:
>  
>      additionalProperties: false
>  
> +patternProperties:
> +  "^(hog-[0-9]+|.+-hog(-[0-9]+)?)$":
> +    type: object
> +    properties:
> +      gpio-hog: true
> +      gpios: true
> +      output-low: true
> +      line-name: true
> +
> +    required:
> +      - gpio-hog
> +      - gpios
> +      - output-low
> +
> +    additionalProperties: false
> +
>  required:
>    - compatible
>    - reg

-- 
Regards,

Laurent Pinchart