Function wiringPiSetup

wiringPi/wiringPi.c:3447–3645

 */

int wiringPiSetup (void)
{
  int   fd ;
  int   model, rev, mem, maker, overVolted ;

  if (wiringPiSetuped)
    return 0 ;

  wiringPiSetuped = true ;

  if (getenv (ENV_DEBUG) != NULL)
    wiringPiDebug = true ;

  if (getenv (ENV_CODES) != NULL)
    wiringPiReturnCodes = true ;

  if (wiringPiDebug)
    printf ("wiringPi: wiringPiSetup called\n") ;

// Get the board ID information. We're not really using the information here,
//	but it will give us information like the GPIO layout scheme (2 variants
//	on the older 26-pin Pi's) and the GPIO peripheral base address.
//	and if we're running on a compute module, then wiringPi pin numbers
//	don't really mean anything, so force native BCM mode anyway.

  piBoardId (&model, &rev, &mem, &maker, &overVolted) ;

  if ((model == PI_MODEL_CM) ||
      (model == PI_MODEL_CM3) ||
      (model == PI_MODEL_CM3P))
    wiringPiMode = WPI_MODE_GPIO ;
  else
    wiringPiMode = WPI_MODE_PINS ;

  if (piGpioLayout () == GPIO_LAYOUT_PI1_REV1)	// A, B, Rev 1, 1.1
  {
    pinToGpio =  pinToGpioR1 ;
    physToGpio = physToGpioR1 ;
  }
  else 					// A2, B2, A+, B+, CM, Pi2, Pi3, Zero, Zero W, Zero 2 W
  {
    pinToGpio =  pinToGpioR2 ;
    physToGpio = physToGpioR2 ;
  }

// Open the master /dev/ memory control device
// Device strategy: December 2016:
//	Try /dev/mem. If that fails, then
//	try /dev/gpiomem. If that fails then game over.

  const char* gpiomemGlobal = gpiomem_global;
  const char* gpiomemModule = gpiomem_BCM;

  if (piRP1Model()) {
    GetRP1Memory();
    gpiomemGlobal = pciemem_RP1;
    gpiomemModule = gpiomem_RP1;