linux-kernel - [PATCH v3 4/5] dt-bindings: display: bridge: Add GPIO display mux binding

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Message-Id: <20230218111712.2380225-5-treapking@chromium.org>
Date:   Sat, 18 Feb 2023 19:17:11 +0800
From:   Pin-yen Lin <treapking@...omium.org>
To:     Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Robert Foss <rfoss@...nel.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Benson Leung <bleung@...omium.org>
Cc:     Chun-Kuang Hu <chunkuang.hu@...nel.org>,
        devicetree@...r.kernel.org,
        Nicolas Boichat <drinkcat@...omium.org>,
        chrome-platform@...ts.linux.dev, linux-kernel@...r.kernel.org,
        Guenter Roeck <groeck@...omium.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        dri-devel@...ts.freedesktop.org,
        linux-mediatek@...ts.infradead.org,
        Philipp Zabel <p.zabel@...gutronix.de>,
        linux-arm-kernel@...ts.infradead.org,
        Pin-yen Lin <treapking@...omium.org>
Subject: [PATCH v3 4/5] dt-bindings: display: bridge: Add GPIO display mux binding

From: Nicolas Boichat <drinkcat@...omium.org>

Add bindings for Generic GPIO mux driver.

Signed-off-by: Nicolas Boichat <drinkcat@...omium.org>
Signed-off-by: Pin-yen Lin <treapking@...omium.org>
---
Rob mentioned that this series can probably use the common MUX bindings.
Those bindings are designed for MUX consumers that requests a certain
MUX configuration, while this driver is reading a GPIO pin controlled
by the other parts of the system (in our use case, it's the embedded
controller firmware).

Changes in v3:
- Removed ddc-i2c-bus in the bindings

Changes in v2:
- Referenced existing dt-binding schemas from graph.yaml
- Added ddc-i2c-bus into the bindings

 .../bindings/display/bridge/gpio-mux.yaml     | 90 +++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml

diff --git a/Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml b/Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml
new file mode 100644
index 000000000000..e6b82ea2f45c
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/bridge/gpio-mux.yaml
@@ -0,0 +1,90 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/bridge/gpio-mux.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Generic display mux (1 input, 2 outputs)
+
+maintainers:
+  - Nicolas Boichat <drinkcat@...omium.org>
+
+description: |
+  This bindings describes a simple display (e.g. HDMI) mux, that has 1
+  input, and 2 outputs. The mux status is controlled by hardware, and
+  its status is read back using a GPIO.
+
+properties:
+  compatible:
+    const: gpio-display-mux
+
+  detect-gpios:
+    maxItems: 1
+    description: GPIO that indicates the active output
+
+  ports:
+    $ref: /schemas/graph.yaml#/properties/ports
+
+    properties:
+      port@0:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: |
+          Video port for input.
+
+      port@1:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: |
+          2 video ports for output.
+          The reg value in the endpoints matches the GPIO status: when
+          GPIO is asserted, endpoint with reg value <1> is selected.
+
+    required:
+      - port@0
+      - port@1
+
+required:
+  - compatible
+  - detect-gpios
+  - ports
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    hdmi_mux: hdmi_mux {
+      compatible = "gpio-display-mux";
+      detect-gpios = <&pio 36 GPIO_ACTIVE_HIGH>;
+      pinctrl-names = "default";
+      pinctrl-0 = <&hdmi_mux_pins>;
+
+      ports {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        port@0 { /* input */
+          reg = <0>;
+
+          hdmi_mux_in: endpoint {
+            remote-endpoint = <&hdmi0_out>;
+          };
+        };
+
+        port@1 { /* output */
+          reg = <1>;
+
+          #address-cells = <1>;
+          #size-cells = <0>;
+
+          hdmi_mux_out_anx: endpoint@0 {
+            reg = <0>;
+            remote-endpoint = <&dp_bridge_in>;
+          };
+
+          hdmi_mux_out_hdmi: endpoint@1 {
+            reg = <1>;
+            remote-endpoint = <&hdmi_connector_in>;
+          };
+        };
+      };
+    };
-- 
2.39.2.637.g21b0678d19-goog