cs4398_write_cached
cs4398_write_cached(chip, 2, cs4398_fm);
cs4398_write_cached(chip, 5, (127 - chip->dac_volume[0]) * 2);
cs4398_write_cached(chip, 6, (127 - chip->dac_volume[1]) * 2);
cs4398_write_cached(chip, 4, reg);