Hardware GPIO

From OpenTom

GPIO means General Purpose Input/Output. It makes use of some of the microcontrollers pins to communicate with the outside world and consists of applying high or low power states on these pins. Depending on what is wired to such a pin anything can happen.

Applications can access the GPIO driver using "/dev/hwstatus" interface. Application will be informed by 1synchronous notification when GPIO hardware status changes. Application may register a signal handler with SIGIO as signal number to receive this signal. On receiving the signal it has to call the ‘ioctl’ system call (with command IOR_HWSTATUS) to get the hardwareStatus structure. Application can also get and set the status of the GPIO output pins using the ioctl's IOR_OUT_PIN_STATUS and IOW_OUT_PIN_STAT

see source code trunk: ..../drivers/Barcelona/GPIO/