dt-bindings: display/bridge: add binding for TH1520 HDMI controller

T-Head TH1520 SoC contains a Synopsys DesignWare HDMI controller paired
with DesignWare HDMI PHY, with an extra clock gate for HDMI pixel clock
and two reset controls.

Add a device tree binding to it.

Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Signed-off-by: Icenowy Zheng <zhengxingda@iscas.ac.cn>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patch.msgid.link/20260129023922.1527729-5-zhengxingda@iscas.ac.cn

Documentation/devicetree/bindings/display/bridge/thead,th1520-dw-hdmi.yaml

@@ -0,0 +1,120 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/bridge/thead,th1520-dw-hdmi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: T-Head TH1520 DesignWare HDMI TX Encoder
+
+maintainers:
+  - Icenowy Zheng <uwu@icenowy.me>
+
+description:
+  The HDMI transmitter is a Synopsys DesignWare HDMI TX controller
+  paired with a DesignWare HDMI Gen2 TX PHY.
+
+allOf:
+  - $ref: /schemas/display/bridge/synopsys,dw-hdmi.yaml#
+
+properties:
+  compatible:
+    enum:
+      - thead,th1520-dw-hdmi
+
+  reg-io-width:
+    const: 4
+
+  clocks:
+    maxItems: 4
+
+  clock-names:
+    items:
+      - const: iahb
+      - const: isfr
+      - const: cec
+      - const: pix
+
+  resets:
+    items:
+      - description: Main reset
+      - description: Configuration APB reset
+
+  reset-names:
+    items:
+      - const: main
+      - const: apb
+
+  ports:
+    $ref: /schemas/graph.yaml#/properties/ports
+
+    properties:
+      port@0:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: Input port connected to DC8200 DPU "DP" output
+
+      port@1:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: HDMI output port
+
+    required:
+      - port@0
+      - port@1
+
+required:
+  - compatible
+  - reg
+  - reg-io-width
+  - clocks
+  - clock-names
+  - resets
+  - reset-names
+  - interrupts
+  - ports
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/clock/thead,th1520-clk-ap.h>
+    #include <dt-bindings/reset/thead,th1520-reset.h>
+
+    soc {
+      #address-cells = <2>;
+      #size-cells = <2>;
+
+      hdmi@ffef540000 {
+        compatible = "thead,th1520-dw-hdmi";
+        reg = <0xff 0xef540000 0x0 0x40000>;
+        reg-io-width = <4>;
+        interrupts = <111 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&clk_vo CLK_HDMI_PCLK>,
+                 <&clk_vo CLK_HDMI_SFR>,
+                 <&clk_vo CLK_HDMI_CEC>,
+                 <&clk_vo CLK_HDMI_PIXCLK>;
+        clock-names = "iahb", "isfr", "cec", "pix";
+        resets = <&rst_vo TH1520_RESET_ID_HDMI>,
+                 <&rst_vo TH1520_RESET_ID_HDMI_APB>;
+        reset-names = "main", "apb";
+
+        ports {
+          #address-cells = <1>;
+          #size-cells = <0>;
+          port@0 {
+            reg = <0>;
+
+            hdmi_in: endpoint {
+              remote-endpoint = <&dpu_out_dp1>;
+            };
+          };
+
+          port@1 {
+            reg = <1>;
+
+            hdmi_out_conn: endpoint {
+              remote-endpoint = <&hdmi_conn_in>;
+            };
+          };
+        };
+      };
+    };