cdev_add
if (cdev_add(misc->cdev, misc->this_device->devt, 1))
ret = cdev_add(ldev, dev->devt, 1);
ret = cdev_add(cdev, makedev(major, i), 1);
if (cdev_add(&ucm_dev->cdev, base, 1))
if (cdev_add(&port->cdev, base, 1))
if (cdev_add(&port->sm_cdev, base, 1))