It's used to support dual role switch via GPIO when use Type-B
receptacle, typically the USB ID pin is connected to an input
GPIO, and also used to enable/disable device when the USB Vbus
pin is connected to an input GPIO.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
---
v9~v10 no changes

v8 changes:
 1. rename the title
 2. change the compatible as "linux,usb-conn-gpio" instead of
    "linux,typeb-conn-gpio"

v7 changes:
 1. add description for device only mode

v6 changes:
 1. remove status and port nodes in example
 2. make vbus-supply as optional property

v5 changes:
 1. treat type-B connector as child device of USB controller's, but not
    as a separate virtual device, suggested by Rob
 2. put connector's port node under connector node, suggested by Rob

v4 no changes

v3 changes:
 1. treat type-B connector as a virtual device, but not child device of
    USB controller's

v2 changes:
  1. new patch to make binding clear suggested by Hans
---
 .../devicetree/bindings/usb/usb-conn-gpio.txt | 31 +++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/usb/usb-conn-gpio.txt

diff --git a/Documentation/devicetree/bindings/usb/usb-conn-gpio.txt b/Documentation/devicetree/bindings/usb/usb-conn-gpio.txt
new file mode 100644
index 000000000000..d4d107fedc22
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/usb-conn-gpio.txt

@@ -0,0 +1,31 @@
+USB GPIO Based Connection Detection
+
+This is typically used to switch dual role mode from the USB ID pin connected
+to an input GPIO, and also used to enable/disable device mode from the USB
+Vbus pin connected to an input GPIO.
+
+Required properties:
+- compatible : should include "linux,usb-conn-gpio" and "usb-b-connector".
+- id-gpios, vbus-gpios : input gpios, either one of them must be present,
+	and both can be present as well.
+	see connector/usb-connector.txt
+
+Optional properties:
+- vbus-supply : can be present if needed when supports dual role mode.
+	see connector/usb-connector.txt
+
+- Sub-nodes:
+	- port : can be present.
+		see graph.txt
+
+Example:
+
+&mtu3 {
+	connector {
+		compatible = "linux,usb-conn-gpio", "usb-b-connector";
+		label = "micro-USB";
+		type = "micro";
+		id-gpios = <&pio 12 GPIO_ACTIVE_HIGH>;
+		vbus-supply = <&usb_p0_vbus>;
+	};
+};

-- 
2.23.0