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Date:   Thu, 28 May 2020 13:48:04 -0600
From:   Rob Herring <robh@kernel.org>
To:     Guido =?iso-8859-1?Q?G=FCnther?= <agx@sigxcpu.org>
Cc:     Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Shawn Guo <shawnguo@kernel.org>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Andrzej Hajda <a.hajda@samsung.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        Anson Huang <Anson.Huang@nxp.com>,
        Leonard Crestez <leonard.crestez@nxp.com>,
        Lucas Stach <l.stach@pengutronix.de>,
        Peng Fan <peng.fan@nxp.com>,
        Robert Chiras <robert.chiras@nxp.com>,
        dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH 1/6] dt-bindings: display/bridge: Add binding for
 input mux bridge
Message-ID: <20200528194804.GA541078@bogus>
References: <cover.1589548223.git.agx@sigxcpu.org>
 <14a44a664f40584ffa25c1764aab5ebf97809c71.1589548223.git.agx@sigxcpu.org>
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On Fri, May 15, 2020 at 03:12:10PM +0200, Guido G?nther wrote:
> The bridge allows to select the input source via a mux controller.
> 
> Signed-off-by: Guido G?nther <agx@sigxcpu.org>
> ---
>  .../display/bridge/mux-input-bridge.yaml      | 123 ++++++++++++++++++
>  1 file changed, 123 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/bridge/mux-input-bridge.yaml
> 
> diff --git a/Documentation/devicetree/bindings/display/bridge/mux-input-bridge.yaml b/Documentation/devicetree/bindings/display/bridge/mux-input-bridge.yaml
> new file mode 100644
> index 000000000000..4029cf63ee5c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/bridge/mux-input-bridge.yaml
> @@ -0,0 +1,123 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/bridge/mux-input-bridge.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: DRM input source selection via multiplexer

DRM is not a hardware thing.

The graph binding is already designed to support muxing. Generally, 
multiple endpoints on an input node is a mux. So either the device with 
the input ports knows how to select the input, or you just need a 
mux-control property for the port to have some other device implement 
the control.

You could do it like you have below. That would be appropriate if 
there's a separate h/w device controlling the muxing. Say for example 
some board level device controlled by i2c.

Rob