- Do not set input flag when reading value from GPIO pin, it is not
required and for gpioc2(S5 bank) setting both input and output flags
leads to some kind of electric interference (curren drop?) that
causes USB devices to disconnect
- Check pad configuration when attaching device and provide IN/OUT
capabilities only for pads that are configured as GPIO. Do not let
user code to configure or change value of non-GPIO pads. There is
no information for NC bank in intel's datasheet so for now function
check is ignored for pins in it
Reported by: Frank H.
MFC after: 3 days
Bay Trail has three banks of GPIOs exposed to userland as /dev/gpiocN,
where N is 1, 2, and 3. Pins in each bank are pre-named to match names
on boards schematics: GPIO_S0_SCnn, GPIO_S0_NCnn, and GPIO_S5_nn.
Controller supports edge-triggered and level-triggered interrupts but
current version of the driver does not have interrupts support
