mma9551_read_config_byte
ret = mma9551_read_config_byte(data->client,
EXPORT_SYMBOL_NS(mma9551_read_config_byte, "IIO_MMA9551");
ret = mma9551_read_config_byte(client, app_id, reg, &orig);
int mma9551_read_config_byte(struct i2c_client *client, u8 app_id,