dt-bindings: platform: Add Huawei Matebook E Go EC

Add binding for the EC found in the Huawei Matebook E Go and
Huawei Matebook E Go LTE 2-in-1 tablets, the former one is a QS sc8280xp
based tablet, the latter one is a QS sc8180x based tablet.

This series has a codename, gaokun. More information about gaokun, please
check https://bugzilla.kernel.org/show_bug.cgi?id=219645

Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250214180656.28599-2-mitltlatltl@gmail.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Documentation/devicetree/bindings/platform/huawei,gaokun-ec.yaml

@@ -0,0 +1,124 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/platform/huawei,gaokun-ec.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Huawei Matebook E Go Embedded Controller
+
+maintainers:
+  - Pengyu Luo <mitltlatltl@gmail.com>
+
+description:
+  Different from other Qualcomm Snapdragon sc8180x and sc8280xp-based
+  machines, the Huawei Matebook E Go tablets use embedded controllers
+  while others use a system called PMIC GLink which handles battery,
+  UCSI, USB Type-C DP Alt Mode. In addition, Huawei's implementation
+  also handles additional features, such as charging thresholds, FN
+  lock, smart charging, tablet lid status, thermal sensors, and more.
+
+properties:
+  compatible:
+    enum:
+      - huawei,gaokun3-ec
+
+  reg:
+    const: 0x38
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+  interrupts:
+    maxItems: 1
+
+patternProperties:
+  '^connector@[01]$':
+    $ref: /schemas/connector/usb-connector.yaml#
+
+    properties:
+      reg:
+        maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        embedded-controller@38 {
+            compatible = "huawei,gaokun3-ec";
+            reg = <0x38>;
+
+            interrupts-extended = <&tlmm 107 IRQ_TYPE_LEVEL_LOW>;
+
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            connector@0 {
+                compatible = "usb-c-connector";
+                reg = <0>;
+                power-role = "dual";
+                data-role = "dual";
+
+                ports {
+                    #address-cells = <1>;
+                    #size-cells = <0>;
+
+                    port@0 {
+                        reg = <0>;
+
+                        ucsi0_ss_in: endpoint {
+                            remote-endpoint = <&usb_0_qmpphy_out>;
+                        };
+                    };
+
+                    port@1 {
+                        reg = <1>;
+
+                        ucsi0_sbu: endpoint {
+                            remote-endpoint = <&usb0_sbu_mux>;
+                        };
+                    };
+                };
+            };
+
+            connector@1 {
+                compatible = "usb-c-connector";
+                reg = <1>;
+                power-role = "dual";
+                data-role = "dual";
+
+                ports {
+                    #address-cells = <1>;
+                    #size-cells = <0>;
+
+                    port@0 {
+                        reg = <0>;
+
+                        ucsi1_ss_in: endpoint {
+                            remote-endpoint = <&usb_1_qmpphy_out>;
+                        };
+                    };
+
+                    port@1 {
+                        reg = <1>;
+
+                        ucsi1_sbu: endpoint {
+                            remote-endpoint = <&usb1_sbu_mux>;
+                        };
+                    };
+                };
+            };
+        };
+    };