PCF8563_REG_MO
tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
buf[PCF8563_REG_MO] |= PCF8563_MO_C;