TX39_IOCTRL_REG
txreg_t reg = tx_conf_read(sc->sc_tc, TX39_IOCTRL_REG);
reg = tx_conf_read(tc, TX39_IOCTRL_REG);
tx_conf_write(tc, TX39_IOCTRL_REG, reg);
reg = tx_conf_read(tc, TX39_IOCTRL_REG);
reg = tx_conf_read(tc, TX39_IOCTRL_REG);