driver/ioexpander: Add gpio_pin_unregister function to GPIO driver
driver/ioexpander: Add pinset struct to GPIO driver for interrupt pins larger than 64
driver/ioexpander: Initialize pintype/inttype when registering ioexpander device
driver/ioexpander: Add SETPINTYPE ioctl command to the GPIO driver
PCA9555 Driver: Replace the signalling logic with a simple callback using the new definitons of ioexpander.h. This repartitioning of functionality is necessary because (1) the I/O expander driver is the lower-lower part of any driver that uses GPIOs (include the GPIO driver itself) and should not be interacting directly with the much higher level application layer. And (2) in order to be compatible with the GPIO driver (and any arbitrary upper half driver), the PCA9555 should not directly signal, but should call back into the upper half. The upper half driver that interacts directly with the application is the appropriate place to be generating signal.
-headers in nuttx/ioexpander to define the "generic" ioexpander framework
-files in drivers/ioexpander for the implementation of the NXP PCA9555 framework
-bindings in drivers/Kconfig and drivers/Makefile
From Sebastien Lorquet
