misc: microchip: pci1xxxx: Add GPIO Wakeup Support

The patch adds PIO asynchronous wakeup support while PIO PCIe Endpoint
function is in D3 state. When such a wakeup event occurs, the PIO
asserts a PIO_WAKE signal, which in turn triggers PCIe Wake signaling.
This wake request should trigger the PCIe Host to take the PIO PCIe
Endpoint function into the D0 device state.

The device supports up to 96 PIOs distributed across three GPIO banks.
During suspend and resume, the driver checks the status of each GPIO bank
to determine if any GPIOs with wake masking enabled have triggered an
event. Upon resume, PIOxx_STATUS register must be cleared by software
explicitly to enable the detection of the next transition.

Signed-off-by: Rengarajan S <rengarajan.s@microchip.com>
Link: https://lore.kernel.org/r/20250513091557.3660-3-rengarajan.s@microchip.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>