i2c_ctrl_io_smbus
extern bool i2c_ctrl_io_smbus(i2c_txn_t *, i2c_ctrl_t *, i2c_port_t *,
ret = i2c_ctrl_io_smbus(txn, ctrl, client->icli_io_port,
bool ret = i2c_ctrl_io_smbus(txn, ctrl, port, smbus);
(void) i2c_ctrl_io_smbus(user->iu_txn, ctrl, nex->in_data.in_port,