dt-bindings: Add ANX6345 DP/eDP transmitter binding

The anx6345 is an ultra-low power DisplayPort/eDP transmitter designed
for portable devices.

Add a binding document for it.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Torsten Duwe <duwe@suse.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>

Documentation/devicetree/bindings/display/bridge/anx6345.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/bridge/anx6345.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analogix ANX6345 eDP Transmitter Device Tree Bindings
+
+maintainers:
+  - Torsten Duwe <duwe@lst.de>
+
+description: |
+  The ANX6345 is an ultra-low power Full-HD eDP transmitter designed for
+  portable devices.
+
+properties:
+  compatible:
+    const: analogix,anx6345
+
+  reg:
+    maxItems: 1
+    description: base I2C address of the device
+
+  reset-gpios:
+    maxItems: 1
+    description: GPIO connected to active low reset
+
+  dvdd12-supply:
+    maxItems: 1
+    description: Regulator for 1.2V digital core power.
+
+  dvdd25-supply:
+    maxItems: 1
+    description: Regulator for 2.5V digital core power.
+
+  ports:
+    type: object
+
+    properties:
+      port@0:
+        type: object
+        description: |
+          Video port for LVTTL input
+
+      port@1:
+        type: object
+        description: |
+          Video port for eDP output (panel or connector).
+          May be omitted if EDID works reliably.
+
+    required:
+      - port@0
+
+required:
+  - compatible
+  - reg
+  - reset-gpios
+  - dvdd12-supply
+  - dvdd25-supply
+  - ports
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c0 {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      anx6345: anx6345@38 {
+        compatible = "analogix,anx6345";
+        reg = <0x38>;
+        reset-gpios = <&pio42 1 /* GPIO_ACTIVE_LOW */>;
+        dvdd25-supply = <&reg_dldo2>;
+        dvdd12-supply = <&reg_fldo1>;
+
+        ports {
+          #address-cells = <1>;
+          #size-cells = <0>;
+
+          anx6345_in: port@0 {
+            #address-cells = <1>;
+            #size-cells = <0>;
+            reg = <0>;
+            anx6345_in_tcon0: endpoint@0 {
+              reg = <0>;
+              remote-endpoint = <&tcon0_out_anx6345>;
+            };
+          };
+
+          anx6345_out: port@1 {
+            #address-cells = <1>;
+            #size-cells = <0>;
+            reg = <1>;
+            anx6345_out_panel: endpoint@0 {
+              reg = <0>;
+              remote-endpoint = <&panel_in_edp>;
+            };
+          };
+        };
+      };
+    };