dt-bindings: usb: usb251xb: add documentation for data lane swapping

Add optional binding to allow USB differential-pair (D+/D-) data lane
swapping. The swapping can be specified for each port separately,
default is no swapping.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Reviewed-by: Richard Leitner <richard.leitner@skidata.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/devicetree/bindings/usb/usb251xb.txt b/Documentation/devicetree/bindings/usb/usb251xb.txt
index 168ff81..17915f6 100644 (file)
--- a/Documentation/devicetree/bindings/usb/usb251xb.txt
+++ b/Documentation/devicetree/bindings/usb/usb251xb.txt
@@ -64,6 +64,8 @@ Optional properties :
  - power-on-time-ms : Specifies the time it takes from the time the host
        initiates the power-on sequence to a port until the port has adequate
        power. The value is given in ms in a 0 - 510 range (default is 100ms).
+ - swap-dx-lanes : Specifies the ports which will swap the differential-pair
+       (D+/D-), default is not-swapped.
 
 Examples:
        usb2512b@2c {
@@ -81,4 +83,6 @@ Examples:
                manufacturer = "Foo";
                product = "Foo-Bar";
                serial = "1234567890A";
+               /* correct misplaced usb connectors on port 1,2 */
+               swap-dx-lanes = <1 2>;
        };