iic_smbus_send_byte
if (iic_smbus_send_byte(dc->dc_tag, dc->dc_addr, reg, 0) != 0)
int iic_smbus_send_byte(i2c_tag_t, i2c_addr_t, uint8_t, int);
if (iic_smbus_send_byte(sc->sc_tag, sc->sc_addr, buf[i], 0))
iic_smbus_send_byte(sc->sc_iicmux.sc_i2c_parent, sc->sc_addr, val,