dt-bindings: Add cros-ec Type C port driver

Some Chrome OS devices with Embedded Controllers (EC) can read and
modify Type C port state.

Add an entry in the DT Bindings documentation that lists out the logical
device and describes the relevant port information, to be used by the
corresponding driver.
Signed-off-by: Prashant Malani <pmalani@chromium.org>
Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/chrome/google,cros-ec-typec.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/chrome/google,cros-ec-typec.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Google Chrome OS EC(Embedded Controller) Type C port driver.
+
+maintainers:
+  - Benson Leung <bleung@chromium.org>
+  - Prashant Malani <pmalani@chromium.org>
+
+description:
+  Chrome OS devices have an Embedded Controller(EC) which has access to
+  Type C port state. This node is intended to allow the host to read and
+  control the Type C ports. The node for this device should be under a
+  cros-ec node like google,cros-ec-spi.
+
+properties:
+  compatible:
+    const: google,cros-ec-typec
+
+  connector:
+    $ref: /schemas/connector/usb-connector.yaml#
+
+required:
+  - compatible
+
+examples:
+  - |+
+    spi0 {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      cros_ec: ec@0 {
+        compatible = "google,cros-ec-spi";
+        reg = <0>;
+
+        typec {
+          compatible = "google,cros-ec-typec";
+
+          #address-cells = <1>;
+          #size-cells = <0>;
+
+          connector@0 {
+            compatible = "usb-c-connector";
+            reg = <0>;
+            power-role = "dual";
+            data-role = "dual";
+            try-power-role = "source";
+          };
+        };
+      };
+    };