Function requestLineV2

wiringPi/wiringPi.c:1799–1857

int requestLineV2(int pin, const unsigned int lineRequestFlags) {
   struct gpio_v2_line_request req;
   struct gpio_v2_line_config config;
   int ret;
   
   if (lineFds[pin]>=0) {
    if (lineRequestFlags == lineFlags[pin]) {
      //already requested
      return lineFds[pin];
    } else {
      //different request -> rerequest
      releaseLine(pin);
    }
  }

  //requested line
  if (wiringPiGpioDeviceGetFd()<0) {
    return -1;  // error
  }
  
  memset(&req, 0, sizeof(req));
  memset(&config, 0, sizeof(config));
  if (lineRequestFlags & WPI_FLAG_INPUT) {
    config.flags |= GPIO_V2_LINE_FLAG_INPUT;
  }
  if (lineRequestFlags & WPI_FLAG_OUTPUT) {
    config.flags |= GPIO_V2_LINE_FLAG_OUTPUT;
  }
  if (lineRequestFlags & WPI_FLAG_BIAS_OFF) {
    config.flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
  }
  if (lineRequestFlags & WPI_FLAG_BIAS_UP) {
    config.flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
  }
  if (lineRequestFlags & WPI_FLAG_BIAS_DOWN) {
    config.flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
  }
  if (wiringPiDebug) {
    printf ("requestLine flags v2: %llu\n", config.flags);
  }
  strcpy(req.consumer, "wiringpi_gpio_req");
  
  req.offsets[0] = pin;
  req.num_lines = 1;
  req.config = config;
  
  ret = ioctl(chipFd, GPIO_V2_GET_LINE_IOCTL, &req);
  
  if (ret || req.fd<0) {
    ReportDeviceError("get line handle v2", pin, "RequestLine", ret);
    return -1;  // error
  }

  lineFlags[pin] = lineRequestFlags;
  lineFds[pin] = req.fd;
  if (wiringPiDebug)
    printf ("requestLine succeeded: pin:%d, flags: 0x%u, fd :%d\n", pin, lineRequestFlags, lineFds[pin]) ;
  return lineFds[pin];