This patch adds binding documentation to support usb hub and usb data role switch of Hisilicon HiKey960 Board. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Rob Herring <robh+dt@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> CC: ShuFan Lee <shufan_lee@richtek.com> Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Chunfeng Yun <chunfeng.yun@mediatek.com> Cc: Yu Chen <chenyu56@huawei.com> Cc: Felipe Balbi <balbi@kernel.org> Cc: Hans de Goede <hdegoede@redhat.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Jun Li <lijun.kernel@gmail.com> Cc: Valentin Schneider <valentin.schneider@arm.com> Cc: Jack Pham <jackp@codeaurora.org> Cc: linux-usb@vger.kernel.org Cc: devicetree@vger.kernel.org Bug: 146450171 Link: https://lore.kernel.org/lkml/20191212014233.32799-8-john.stultz@linaro.org/ Signed-off-by: Yu Chen <chenyu56@huawei.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Change-Id: I3f111b39b7a982b3489549076412a2f7c3c3d008