func NewMMappedGPIO(number uint, direction int) (gpio *MMappedGPIO) {
	NewSysfsGPIOOrPanic(number, direction).Close()
	gpio = new(MMappedGPIO)
	gpio.chipid, gpio.gpioid = calcGPIOAddrFromLinuxGPIONum(number)
	return gpio
}
/ Fast MemoryMapped GPIO Stuff -----------------------------------------
Instantinate a new and fast GPIO controlled using direct access to AM335x registers.
Takes GPIO numer (same as in sysfs) and direction bbhw.IN or bbhw.OUT
Only works on AM335x and address compatible SoCs

See http://kilobaser.com/blog/2014-07-15-beaglebone-black-gpios#1gpiopin regarding the numbering of GPIO pins.
package bbhw
import "fmt"
type MMappedGPIO struct {
	chipid    int
	gpioid    uint
	activelow bool
}