ST7_CONTROL
reg = stvii_readreg(sc, ST7_CONTROL);
stvii_writereg(sc, ST7_CONTROL, reg);
reg = stvii_readreg(sc, ST7_CONTROL);
stvii_writereg(sc, ST7_CONTROL, sc->sc_control);
ctl = stvii_readreg(sc, ST7_CONTROL);
stvii_writereg(sc, ST7_CONTROL, ctl & ~(STC_MAIN_POWER | STC_DDR_POWER));