[v2 PATCH] dt-binding: usb: add usb-role-switch property

[Chunfeng Yun]

Add a property usb-role-switch to tell Dual-Role controller driver
that use USB Role Switch framework to handle the role switch between
host mode and device mode, it's useful when the driver has already
supported other ways, such as extcon framework etc.

Cc: Biju Das <biju.das@xxxxxxxxxxxxxx>
Cc: Yu Chen <chenyu56@xxxxxxxxxx>
Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
---
v2:
    describe it in terms of h/w functionality suggested by Rob

v1:
    the property is discussed in:
    [v2,2/7] dt-bindings: usb: renesas_usb3: add usb-role-switch property
    https://patchwork.kernel.org/patch/10852497/

    Mediatek and Hisilicon also try to use it:
    [v4,3/6] dt-bindings: usb: mtu3: add properties about USB Role Switch
    https://patchwork.kernel.org/patch/10918385/
    [v4,6/6] usb: mtu3: register a USB Role Switch for dual role mode
    https://patchwork.kernel.org/patch/10918367/

    [v6,10/13] usb: dwc3: Registering a role switch in the DRD code
    https://patchwork.kernel.org/patch/10909981/
---
 Documentation/devicetree/bindings/usb/generic.txt | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/usb/generic.txt b/Documentation/devicetree/bindings/usb/generic.txt
index 0a74ab8dfdc2..f5a6ad053ecc 100644
--- a/Documentation/devicetree/bindings/usb/generic.txt
+++ b/Documentation/devicetree/bindings/usb/generic.txt
@@ -30,6 +30,11 @@ Optional properties:
 			optional for OTG device.
  - adp-disable: tells OTG controllers we want to disable OTG ADP, ADP is
 			optional for OTG device.
+ - usb-role-switch: tells Dual-Role USB controllers we want to handle the role
+			switch between host and device according to the state
+			detected by the USB connector, typically for Type-C,
+			Type-B(micro).
+			see connector/usb-connector.txt.
 
 This is an attribute to a USB controller such as:
 
-- 
2.21.0