gpio_vbus provides simple GPIO VBUS sensing for peripheral
controllers with an internal transceiver.
Optionally, a second GPIO can be used to control D+ pullup.

It also interfaces with the regulator framework to limit charging
currents when powered via USB. gpio_vbus requests the regulator
supplying "vbus_draw" and can enable/disable it or limit its
current depending on USB state.

[dbrownell@users.sourceforge.net: use drivers/otg, cleanups ]
Signed-off-by: NPhilipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>