153 lines
4.0 KiB
Go
153 lines
4.0 KiB
Go
package spi
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import (
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"log"
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"sync"
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"gobot.io/x/gobot/v2"
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)
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const (
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// NotInitialized is the initial value for a bus/chip
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NotInitialized = -1
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)
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// Connector lets adaptors provide the interface for Drivers
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// to get access to the SPI buses on platforms that support SPI.
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type Connector interface {
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// GetSpiConnection returns a connection to a SPI device at the specified bus and chip.
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// Bus numbering starts at index 0, the range of valid buses is
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// platform specific. Same with chip numbering.
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GetSpiConnection(busNum, chip, mode, bits int, maxSpeed int64) (device Connection, err error)
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// SpiDefaultBusNumber returns the default SPI bus index
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SpiDefaultBusNumber() int
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// SpiDefaultChipNumber returns the default SPI chip index
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SpiDefaultChipNumber() int
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// DefaultMode returns the default SPI mode (0/1/2/3)
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SpiDefaultMode() int
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// SpiDefaultBitCount returns the default SPI number of bits (8)
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SpiDefaultBitCount() int
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// SpiDefaultMaxSpeed returns the max SPI speed
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SpiDefaultMaxSpeed() int64
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}
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// Connection is a connection to a SPI device with a specific bus/chip.
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// Provided by an Adaptor, usually just by calling the spi package's GetSpiConnection() function.
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type Connection gobot.SpiOperations
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// Config is the interface which describes how a Driver can specify
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// optional SPI params such as which SPI bus it wants to use.
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type Config interface {
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// SetBusNumber sets which bus to use
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SetBusNumber(bus int)
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// GetBusNumberOrDefault gets which bus to use
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GetBusNumberOrDefault(def int) int
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// SetChipNumber sets which chip to use
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SetChipNumber(chip int)
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// GetChipNumberOrDefault gets which chip to use
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GetChipNumberOrDefault(def int) int
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// SetMode sets which mode to use
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SetMode(mode int)
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// GetModeOrDefault gets which mode to use
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GetModeOrDefault(def int) int
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// SetUsedBits sets how many bits to use
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SetBitCount(count int)
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// GetBitCountOrDefault gets how many bits to use
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GetBitCountOrDefault(def int) int
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// SetSpeed sets which speed to use (in Hz)
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SetSpeed(speed int64)
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// GetSpeedOrDefault gets which speed to use (in Hz)
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GetSpeedOrDefault(def int64) int64
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}
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// Driver implements the interface gobot.Driver for SPI devices.
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type Driver struct {
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name string
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connector Connector
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connection Connection
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afterStart func() error
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beforeHalt func() error
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Config
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gobot.Commander
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mutex sync.Mutex
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}
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// NewDriver creates a new generic and basic SPI gobot driver.
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func NewDriver(a Connector, name string, options ...func(Config)) *Driver {
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d := &Driver{
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name: gobot.DefaultName(name),
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connector: a,
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afterStart: func() error { return nil },
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beforeHalt: func() error { return nil },
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Config: NewConfig(),
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Commander: gobot.NewCommander(),
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}
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for _, option := range options {
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option(d)
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}
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return d
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}
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// Name returns the name of the device.
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func (d *Driver) Name() string { return d.name }
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// SetName sets the name of the device.
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func (d *Driver) SetName(n string) { d.name = n }
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// Connection returns the Connection of the device.
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func (d *Driver) Connection() gobot.Connection {
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if conn, ok := d.connector.(gobot.Connection); ok {
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return conn
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}
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log.Printf("%s has no gobot connection\n", d.name)
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return nil
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}
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// Start initializes the driver.
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func (d *Driver) Start() error {
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d.mutex.Lock()
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defer d.mutex.Unlock()
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bus := d.GetBusNumberOrDefault(d.connector.SpiDefaultBusNumber())
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chip := d.GetChipNumberOrDefault(d.connector.SpiDefaultChipNumber())
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mode := d.GetModeOrDefault(d.connector.SpiDefaultMode())
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bits := d.GetBitCountOrDefault(d.connector.SpiDefaultBitCount())
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maxSpeed := d.GetSpeedOrDefault(d.connector.SpiDefaultMaxSpeed())
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var err error
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d.connection, err = d.connector.GetSpiConnection(bus, chip, mode, bits, maxSpeed)
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if err != nil {
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return err
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}
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return d.afterStart()
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}
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// Halt stops the driver.
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func (d *Driver) Halt() error {
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d.mutex.Lock()
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defer d.mutex.Unlock()
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if err := d.beforeHalt(); err != nil {
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return err
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}
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// currently there is nothing to do here for the driver, the connection is cached on adaptor side
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// and will be closed on adaptor Finalize()
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return nil
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}
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