usb_ref_device
static usb_error_t usb_ref_device(struct usb_cdev_privdata *, struct usb_cdev_refdata *, int);
err = usb_ref_device(cpd, &refs, 0 /* no uref */ );
if (usb_ref_device(cpd, &refs, 1 /* need uref */)) {
err = usb_ref_device(cpd, &refs, 0 /* no uref */ );
err = usb_ref_device(cpd, &refs, 0 /* no uref */ );
err = usb_ref_device(cpd, &refs, 0 /* no uref */ );
err = usb_ref_device(cpd, &refs, 0 /* no uref */ );
err = usb_ref_device(cpd, &refs, 0 /* no uref */ );
err = usb_ref_device(cpd, &refs, 0 /* no uref */ );
return (usb_ref_device(cpd, crd, 1 /* need uref */));
err = usb_ref_device(cpd, &refs, 1);
err = usb_ref_device(cpd, &refs, 2);