usb: roles: Add Intel xHCI USB role switch driver
authorHans de Goede <hdegoede@redhat.com>
Tue, 20 Mar 2018 12:57:10 +0000 (15:57 +0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 22 Mar 2018 12:49:27 +0000 (13:49 +0100)
commitf6fb9ec02be1c1718596622263a88ff5490d2e95
treeb81b1094f5218b7ed70069e985e6ee6e984b63a8
parentfa31b3cb2ae143aa6e26974fcbe75689da60bdbe
usb: roles: Add Intel xHCI USB role switch driver

Various Intel SoCs (Cherry Trail, Broxton and others) have an internal USB
role switch for swiching the OTG USB data lines between the xHCI host
controller and the dwc3 gadget controller.

Note on some Cherry Trail systems there is ACPI/AML code listening to
edge interrupts on the id-pin (through an _AIE ACPI method) and switching
the role between ROLE_HOST and ROLE_NONE based on the id-pin. Note it does
not set the role to ROLE_DEVICE, because device-mode is usually not used
under Windows.

The presence of AML code which modifies the cfg0 reg (on some systems)
means that our read/write/modify of cfg0 may race with the AML code
doing the same to avoid this we take the global ACPI lock while doing
the read/write/modify.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
MAINTAINERS
drivers/usb/Kconfig
drivers/usb/Makefile
drivers/usb/roles/Kconfig [new file with mode: 0644]
drivers/usb/roles/Makefile [new file with mode: 0644]
drivers/usb/roles/intel-xhci-usb-role-switch.c [new file with mode: 0644]