endpoint_byreg
ep = endpoint_byreg(dp, -1, -1);
ep = endpoint_byreg(&sc->sc_ports, ANXDP_PORT_OUTPUT, 0);
ep = endpoint_byreg(&sc->sc_ports, 0, -1);
ep = endpoint_byreg(&sc->sc_ports, 0, -1);
struct endpoint *endpoint_byreg(struct device_ports *, uint32_t, uint32_t);