code: func GetSpiConnection(busNum, chipNum, mode, bits int, maxSpeed int64) (Connection, error) {
  	p, err := xsysfs.NewSPI(busNum, chipNum)
  	if err != nil {
  		return nil, err
  	}
  	c, err := p.Connect(physic.Frequency(maxSpeed)*physic.Hertz, xspi.Mode(mode), bits)
  	if err != nil {
  		return nil, err
  	}
  	return NewConnection(p, c), nil
  }
docs: // GetSpiConnection is a helper to return a SPI device.