[v3 PATCH] dt-binding: usb: add usb-role-switch property

[Chunfeng Yun]

Add a property usb-role-switch to tell the driver that use
USB Role Switch framework to handle the role switch,
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>
---
v3:
    add property type, modify description suggested by Heikki

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 | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/usb/generic.txt b/Documentation/devicetree/bindings/usb/generic.txt
index 0a74ab8dfdc2..cf5a1ad456e6 100644
--- a/Documentation/devicetree/bindings/usb/generic.txt
+++ b/Documentation/devicetree/bindings/usb/generic.txt
@@ -30,6 +30,10 @@ 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: boolean, indicates that the device is capable of assigning
+			the USB data role (USB host or USB device) for a given
+			USB connector, such as Type-C, Type-B(micro).
+			see connector/usb-connector.txt.
 
 This is an attribute to a USB controller such as:
 
-- 
2.21.0