dt-bindings: usb: typec: add bindings for stm32g0 controller

Add DT schema documentation for the STM32G0 Type-C PD (Power Delivery)
controller.
STM32G0 provides an integrated USB Type-C and power delivery interface.
It can be programmed with a firmware to handle UCSI protocol over I2C
interface. A GPIO is used as an interrupt line.
It may be used as a wakeup source, so use optional "wakeup-source" and
"power-domains" properties to support wakeup.
The firmware itself may be flashed or later updated (optional). Choice is
let to the application to allow firmware update. A default firmware could
be already programmed in production and be customized (to not allow it).
So the firmware-name is made optional to represent this option.

Reviewed-by: Rob Herring <[e-mail]>
Signed-off-by: Fabrice Gasnier <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/devicetree/bindings/usb/st,typec-stm32g0.yaml

···
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/usb/st,typec-stm32g0.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: STMicroelectronics STM32G0 USB Type-C PD controller
+
+description: |
+  The STM32G0 MCU can be programmed to control Type-C connector(s) through I2C
+  typically using the UCSI protocol over I2C, with a dedicated alert
+  (interrupt) pin.
+
+maintainers:
+  - Fabrice Gasnier <[e-mail]>
+
+properties:
+  compatible:
+    const: st,stm32g0-typec
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  connector:
+    type: object
+    $ref: /schemas/connector/usb-connector.yaml#
+    unevaluatedProperties: false
+
+  firmware-name:
+    description: |
+      Should contain the name of the default firmware image
+      file located on the firmware search path
+
+  wakeup-source: true
+
+  power-domains:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - connector
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      typec@53 {
+        compatible = "st,stm32g0-typec";
+        reg = <0x53>;
+        /* Alert pin on GPIO PE12 */
+        interrupts = <12 IRQ_TYPE_EDGE_FALLING>;
+        interrupt-parent = <&gpioe>;
+
+        /* Example with one type-C connector */
+        connector {
+          compatible = "usb-c-connector";
+          label = "USB-C";
+
+          ports {
+            #address-cells = <1>;
+            #size-cells = <0>;
+            port@0 {
+              reg = <0>;
+              con_usb_c_ep: endpoint {
+                remote-endpoint = <&usb_ep>;
+              };
+            };
+          };
+        };
+      };
+    };
+
+    usb {
+      usb-role-switch;
+      port {
+        usb_ep: endpoint {
+          remote-endpoint = <&con_usb_c_ep>;
+        };
+      };
+    };
+...