code: func (c *i2cConnection) WriteByteData(reg uint8, val uint8) (err error) {
  	c.mutex.Lock()
  	defer c.mutex.Unlock()
  
  	if err := c.bus.SetAddress(c.address); err != nil {
  		return err
  	}
  	return c.bus.WriteByteData(reg, val)
  }
docs: // WriteByteData writes a byte value to a register on the i2c device.