IWM_CSR_LED_REG
IWM_WRITE(sc, IWM_CSR_LED_REG, IWM_CSR_LED_REG_TURN_ON);
IWM_WRITE(sc, IWM_CSR_LED_REG, IWM_CSR_LED_REG_TURN_OFF);
return (IWM_READ(sc, IWM_CSR_LED_REG) == IWM_CSR_LED_REG_TURN_ON);