cd->set_state_periodic = constant_set_state_periodic;
cd->set_state_shutdown = constant_set_state_shutdown;
cd->set_next_event = constant_timer_next_event;
cd->set_state_periodic = constant_set_state_periodic;
cd->set_state_shutdown = constant_set_state_shutdown;
cd->set_next_event = constant_timer_next_event;