Function wiringPiGpioDeviceGetFd

wiringPi/wiringPi.c:1772–1786

}

int wiringPiGpioDeviceGetFd() {
  if (chipFd<0) {
    piBoard();
    if (piRP1Model()) {
      chipFd = OpenAndCheckGpioChip(0, "rp1", 54);   // /dev/gpiochip0 @ Pi5 since Kernel 6.6.47
      if (chipFd<0) {
        chipFd = OpenAndCheckGpioChip(4, "rp1", 54);  // /dev/gpiochip4 @ Pi5 with older kernel
      }
    } else {
      // not all Pis have same number of lines: Pi0, Pi1, Pi3, 54 lines, Pi4, 58 lines (CM ?), see #280, so this check is disabled
      chipFd = OpenAndCheckGpioChip(0, "bcm", 0);
    }
  }
  return chipFd;
}

void releaseLine(int pin) {