Registering port

 /* Registering port */
  port = check_region(0x378, 1);      //0x378 是 parlel port 的記憶體位置
  if (port) {
    printk("parlelport: cannot reserve 0x378\n");
    result = port;
    goto fail;
  }
  request_region(0x378, 1, "parlelport");