M48T86_SEC
m48t86_writeb(dev, tm->tm_sec, M48T86_SEC);
m48t86_writeb(dev, bin2bcd(tm->tm_sec), M48T86_SEC);
tm->tm_sec = m48t86_readb(dev, M48T86_SEC);
tm->tm_sec = bcd2bin(m48t86_readb(dev, M48T86_SEC));