USB: gadget: atmel_usba_udc: PM driver improvements

Start clocks on rising edge of the Vbus signal, stop clocks on falling edge of the Vbus signal.

Add suspend/resume with wakeup support.

Changes since v6:
* Removed single IRQ edge support, which was used to wake up only on device connection. We don't have yet a clean solution to handle IRQ controller with (at91sam9x5) and without (at91rm9200) single edge support. Rework PATCH v6 4/5 removed, we don't need this one anymore.

Changes since v5:
* Some boards does not support configuring a GPIO interrupt on a specific edge (rising only or falling only). As suggested added a config boolean to distinguish between boards with and without support
* Added a missing mutex_lock()/unlock() in usba_udc_suspend(), we need to protect usba_stop() because usba_start() and usba_stop() can still be called by Vbus IRQ handler.
* Rebased the full series on linux-next
* Patch cleaning with the help of checkpatch.pl

Changes since v4:
* Now using IRQ_NOAUTOEN flag to remove the unused check for

    udc->driver is not NULL in the Vbus IRQ.

* Reworked the start/stop of clocks on Vbus edges to prepare for suspend/resume support, factorised start and stop procedures
* New patch, suspend/resume for USBA with wakeup support

Changes since v3:
* Added stable tag for the first patch
* As suggested, removed the unused check for udc->driver is NULL in

    Vbus IRQ by requesting IRQ after udc->driver is set and by releasing
    IRQ before udc->driver is cleared

* Rebased the core patch of this series against the just explained changes

Changes since v2:
* Use spin_lock_irqsave/unlock_irqrestore instead of spin_lock/unlock in threaded interrupt because we are not in irq context anymore
* Removed useless and probably harmful IRQF_NO_SUSPEND from devm_request_threaded_irq() flags

Changes since v1:
* Using a threaded irq and mutex instead of spinclock as suggested
* Moved a silently fixed bug in a separate patch (1/2)

Sylvain Rochet (4):
USB: gadget: atmel_usba_udc: Fixed vbus_prev initial state
USB: gadget: atmel_usba_udc: Request an auto disabled Vbus signal IRQ
instead of an auto enabled IRQ request followed by IRQ disable
USB: gadget: atmel_usba_udc: Start clocks on rising edge of the Vbus
signal, stop clocks on falling edge of the Vbus signal
USB: gadget: atmel_usba_udc: Add suspend/resume with wakeup support

 drivers/usb/gadget/udc/atmel_usba_udc.c | 208 ++++++++++++++++++++++++--------
 drivers/usb/gadget/udc/atmel_usba_udc.h |   4 +
 2 files changed, 159 insertions(+), 53 deletions(-)