_regmap_raw_read
ret = _regmap_raw_read(map, reg, work_val, map->format.val_bytes, false);
ret = _regmap_raw_read(map, reg, val, chunk_bytes, false);
ret = _regmap_raw_read(map, reg, val, val_len, false);
ret = _regmap_raw_read(map, reg, val, read_len, true);