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The HiKey960 has a fairly complex USB configuration due to it needing to support a USB-C port for host/device mode and multiple USB-A ports in host mode using a single USB controller. See schematics here: https://github.com/96boards/documentation/raw/master/consumer/hikey/hikey960/hardware-docs/HiKey960_Schematics.pdf This driver acts as a usb-role-switch intermediary, intercepting the role switch notifications from the tcpm code, and passing them on to the dwc3 core. In doing so, it also controls the onboard hub and power gpios in order to properly route the data lines between the USB-C port and the onboard hub to the USB-A ports. NOTE: It was noted that controlling the TYPEC_VBUS_POWER_OFF and TYPEC_VBUS_POWER_ON values here is not reccomended. I'm looking for a way to remove that bit from the logic here, but wanted to still get feedback on this approach. 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/20191212014233.32799-9-john.stultz@linaro.org/ Signed-off-by: Yu Chen <chenyu56@huawei.com> [jstultz: Major rework to make the driver a usb-role-switch intermediary] Signed-off-by: John Stultz <john.stultz@linaro.org> Change-Id: Icf381520abd46d083750d01f91e478321560fbf9