65 lines
1.9 KiB
Go
65 lines
1.9 KiB
Go
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package system
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import (
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"fmt"
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"periph.io/x/conn/v3/physic"
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xspi "periph.io/x/conn/v3/spi"
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xsysfs "periph.io/x/host/v3/sysfs"
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)
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// spiConnectionPeriphIo is the implementation of the SPI interface using the periph.io sysfs implementation for Linux.
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type spiConnectionPeriphIo struct {
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port xspi.PortCloser
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dev xspi.Conn
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}
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// newSpiConnectionPeriphIo creates and returns a new connection to a specific SPI device on a bus/chip
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// using the periph.io interface.
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func newSpiConnectionPeriphIo(busNum, chipNum, mode, bits int, maxSpeed int64) (*spiConnectionPeriphIo, error) {
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p, err := xsysfs.NewSPI(busNum, chipNum)
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if err != nil {
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return nil, err
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}
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c, err := p.Connect(physic.Frequency(maxSpeed)*physic.Hertz, xspi.Mode(mode), bits)
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if err != nil {
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return nil, err
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}
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return &spiConnectionPeriphIo{port: p, dev: c}, nil
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}
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// Close the SPI connection. Implements gobot.BusOperations.
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func (c *spiConnectionPeriphIo) Close() error {
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return c.port.Close()
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}
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// ReadCommandData uses the SPI device TX to send/receive data.
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func (c *spiConnectionPeriphIo) ReadCommandData(command []byte, data []byte) error {
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dataLen := len(data)
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if err := c.dev.Tx(command, data); err != nil {
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return err
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}
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if len(data) != dataLen {
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return fmt.Errorf("Read length (%d) differ to expected (%d)", len(data), dataLen)
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}
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return nil
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}
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// WriteByte uses the SPI device TX to send a byte value. Implements gobot.BusOperations.
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func (c *spiConnectionPeriphIo) WriteByte(val byte) error {
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return c.WriteBytes([]byte{val})
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}
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// WriteBlockData uses the SPI device TX to send data. Implements gobot.BusOperations.
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func (c *spiConnectionPeriphIo) WriteBlockData(reg byte, data []byte) error {
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buf := make([]byte, len(data)+1)
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copy(buf[1:], data)
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buf[0] = reg
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return c.WriteBytes(data)
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}
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// WriteBytes uses the SPI device TX to send the given data.
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func (c *spiConnectionPeriphIo) WriteBytes(data []byte) error {
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return c.dev.Tx(data, nil)
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}
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