pidff_set
pidff_set(&pidff->set_effect[PID_GAIN], magnitude);
pidff_set(&pidff->set_periodic[PID_PHASE], effect->u.periodic.phase);
pidff_set(&pidff->set_condition[PID_POS_SATURATION],
pidff_set(&pidff->set_condition[PID_NEG_SATURATION],
pidff_set(&pidff->set_condition[PID_DEAD_BAND],
pidff_set(&pidff->device_gain[PID_DEVICE_GAIN_FIELD], gain);