spi: switch to using periph.io for SPI interfaces

Signed-off-by: Ron Evans <[email protected]>

Gopkg.toml

@@ -79,7 +79,7 @@
 
 [[constraint]]
   branch = "master"
-  name = "golang.org/x/exp"
+  name = "periph.io/x/periph"
 
 [[constraint]]
   branch = "master"

drivers/spi/apa102.go

@@ -42,9 +42,11 @@ func (d *APA102Driver) Connection() gobot.Connection { return d.connection.(gobo
 // Start initializes the driver.
 func (d *APA102Driver) Start() (err error) {
 	bus := d.connector.GetSpiDefaultBus()
+	chip := d.connector.GetSpiDefaultChip()
 	mode := d.connector.GetSpiDefaultMode()
+	bits := d.connector.GetSpiDefaultBits()
 	maxSpeed := d.connector.GetSpiDefaultMaxSpeed()
-	d.connection, err = d.connector.GetSpiConnection(bus, mode, maxSpeed)
+	d.connection, err = d.connector.GetSpiConnection(bus, chip, mode, bits, maxSpeed)
 	if err != nil {
 		return err
 	}

drivers/spi/doc.go

@@ -1,6 +1,6 @@
 /*
 Package spi provides Gobot drivers for spi devices.
-Uses "golang.org/x/exp/io/spi" for spi
+Uses periph.io for spi
 Installing:
 	go get -d -u gobot.io/x/gobot
 For further information refer to spi README:

drivers/spi/mcp3002.go

@@ -42,9 +42,11 @@ func (d *MCP3002Driver) Connection() gobot.Connection { return d.connection.(gob
 // Start initializes the driver.
 func (d *MCP3002Driver) Start() (err error) {
 	bus := d.connector.GetSpiDefaultBus()
+	chip := d.connector.GetSpiDefaultChip()
 	mode := d.connector.GetSpiDefaultMode()
+	bits := d.connector.GetSpiDefaultBits()
 	maxSpeed := d.connector.GetSpiDefaultMaxSpeed()
-	d.connection, err = d.connector.GetSpiConnection(bus, mode, maxSpeed)
+	d.connection, err = d.connector.GetSpiConnection(bus, chip, mode, bits, maxSpeed)
 	if err != nil {
 		return err
 	}

drivers/spi/mcp3004.go

@@ -42,9 +42,11 @@ func (d *MCP3004Driver) Connection() gobot.Connection { return d.connection.(gob
 // Start initializes the driver.
 func (d *MCP3004Driver) Start() (err error) {
 	bus := d.connector.GetSpiDefaultBus()
+	chip := d.connector.GetSpiDefaultChip()
 	mode := d.connector.GetSpiDefaultMode()
+	bits := d.connector.GetSpiDefaultBits()
 	maxSpeed := d.connector.GetSpiDefaultMaxSpeed()
-	d.connection, err = d.connector.GetSpiConnection(bus, mode, maxSpeed)
+	d.connection, err = d.connector.GetSpiConnection(bus, chip, mode, bits, maxSpeed)
 	if err != nil {
 		return err
 	}

drivers/spi/mcp3008.go

@@ -42,9 +42,11 @@ func (d *MCP3008Driver) Connection() gobot.Connection { return d.connection.(gob
 // Start initializes the driver.
 func (d *MCP3008Driver) Start() (err error) {
 	bus := d.connector.GetSpiDefaultBus()
+	chip := d.connector.GetSpiDefaultChip()
 	mode := d.connector.GetSpiDefaultMode()
+	bits := d.connector.GetSpiDefaultBits()
 	maxSpeed := d.connector.GetSpiDefaultMaxSpeed()
-	d.connection, err = d.connector.GetSpiConnection(bus, mode, maxSpeed)
+	d.connection, err = d.connector.GetSpiConnection(bus, chip, mode, bits, maxSpeed)
 	if err != nil {
 		return err
 	}
@@ -72,7 +74,7 @@ func (d *MCP3008Driver) Read(channel int) (result int, err error) {
 
 	err = d.connection.Tx(tx, rx)
 	if err == nil && len(rx) == 3 {
-		result = int(((rx[1] & 0x3) << 8) + rx[2])
+		result = int((rx[1]&0x3))<<8 + int(rx[2])
 	}
 
 	return result, err

drivers/spi/mcp3202.go

@@ -42,9 +42,11 @@ func (d *MCP3202Driver) Connection() gobot.Connection { return d.connection.(gob
 // Start initializes the driver.
 func (d *MCP3202Driver) Start() (err error) {
 	bus := d.connector.GetSpiDefaultBus()
+	chip := d.connector.GetSpiDefaultChip()
 	mode := d.connector.GetSpiDefaultMode()
+	bits := d.connector.GetSpiDefaultBits()
 	maxSpeed := d.connector.GetSpiDefaultMaxSpeed()
-	d.connection, err = d.connector.GetSpiConnection(bus, mode, maxSpeed)
+	d.connection, err = d.connector.GetSpiConnection(bus, chip, mode, bits, maxSpeed)
 	if err != nil {
 		return err
 	}

drivers/spi/mcp3204.go

@@ -42,9 +42,11 @@ func (d *MCP3204Driver) Connection() gobot.Connection { return d.connection.(gob
 // Start initializes the driver.
 func (d *MCP3204Driver) Start() (err error) {
 	bus := d.connector.GetSpiDefaultBus()
+	chip := d.connector.GetSpiDefaultChip()
 	mode := d.connector.GetSpiDefaultMode()
+	bits := d.connector.GetSpiDefaultBits()
 	maxSpeed := d.connector.GetSpiDefaultMaxSpeed()
-	d.connection, err = d.connector.GetSpiConnection(bus, mode, maxSpeed)
+	d.connection, err = d.connector.GetSpiConnection(bus, chip, mode, bits, maxSpeed)
 	if err != nil {
 		return err
 	}

drivers/spi/mcp3208.go

@@ -42,9 +42,11 @@ func (d *MCP3208Driver) Connection() gobot.Connection { return d.connection.(gob
 // Start initializes the driver.
 func (d *MCP3208Driver) Start() (err error) {
 	bus := d.connector.GetSpiDefaultBus()
+	chip := d.connector.GetSpiDefaultChip()
 	mode := d.connector.GetSpiDefaultMode()
+	bits := d.connector.GetSpiDefaultBits()
 	maxSpeed := d.connector.GetSpiDefaultMaxSpeed()
-	d.connection, err = d.connector.GetSpiConnection(bus, mode, maxSpeed)
+	d.connection, err = d.connector.GetSpiConnection(bus, chip, mode, bits, maxSpeed)
 	if err != nil {
 		return err
 	}

drivers/spi/mcp3304.go

@@ -42,9 +42,11 @@ func (d *MCP3304Driver) Connection() gobot.Connection { return d.connection.(gob
 // Start initializes the driver.
 func (d *MCP3304Driver) Start() (err error) {
 	bus := d.connector.GetSpiDefaultBus()
+	chip := d.connector.GetSpiDefaultChip()
 	mode := d.connector.GetSpiDefaultMode()
+	bits := d.connector.GetSpiDefaultBits()
 	maxSpeed := d.connector.GetSpiDefaultMaxSpeed()
-	d.connection, err = d.connector.GetSpiConnection(bus, mode, maxSpeed)
+	d.connection, err = d.connector.GetSpiConnection(bus, chip, mode, bits, maxSpeed)
 	if err != nil {
 		return err
 	}

drivers/spi/spi.go

@@ -2,103 +2,93 @@ package spi
 
 import (
 	"fmt"
-	"time"
+	"log"
 
-	xspi "golang.org/x/exp/io/spi"
+	xspi "periph.io/x/periph/conn/spi"
+	"periph.io/x/periph/conn/spi/spireg"
+	"periph.io/x/periph/host"
 )
 
 const (
 	// BusNotInitialized is the initial value for a bus
 	BusNotInitialized = -1
 )
 
-type SPIOperations interface {
+// Operations are the wrappers around the actual functions used by the SPI Device interface
+type Operations interface {
 	Close() error
-	SetBitOrder(o xspi.Order) error
-	SetBitsPerWord(bits int) error
-	SetCSChange(leaveEnabled bool) error
-	SetDelay(t time.Duration) error
-	SetMaxSpeed(speed int) error
-	SetMode(mode xspi.Mode) error
 	Tx(w, r []byte) error
 }
 
-// SPIDevice is the interface to a specific spi bus
-type SPIDevice interface {
-	SPIOperations
+// Device is the interface to a specific spi bus/chip
+type Device interface {
+	Operations
 }
 
 // Connector lets Adaptors provide the interface for Drivers
 // to get access to the SPI buses on platforms that support SPI.
 type Connector interface {
-	// GetConnection returns a connection to device at the specified bus.
+	// GetSpiConnection returns a connection to a SPI device at the specified bus and chip.
 	// Bus numbering starts at index 0, the range of valid buses is
-	// platform specific.
-	GetSpiConnection(busNum, mode int, maxSpeed int64) (device Connection, err error)
+	// platform specific. Same with chip numbering.
+	GetSpiConnection(busNum, chip, mode, bits int, maxSpeed int64) (device Device, err error)
 
-	// GetDefaultBus returns the default SPI bus index
+	// GetSpiDefaultBus returns the default SPI bus index
 	GetSpiDefaultBus() int
 
+	// GetSpiDefaultChip returns the default SPI chip index
+	GetSpiDefaultChip() int
+
 	// GetDefaultMode returns the default SPI mode (0/1/2/3)
 	GetSpiDefaultMode() int
 
+	// GetDefaultMode returns the default SPI number of bits (8)
+	GetSpiDefaultBits() int
+
 	// GetSpiDefaultMaxSpeed returns the max SPI speed
 	GetSpiDefaultMaxSpeed() int64
 }
 
-// Connection is a connection to an SPI device with a specified address
-// on a specific bus. Used as an alternative to the SPI interface.
+// Connection is a connection to an SPI device with a specified bus
+// on a specific chip.
 // Implements SPIOperations to talk to the device, wrapping the
 // calls in SetAddress to always target the specified device.
 // Provided by an Adaptor by implementing the SPIConnector interface.
-type Connection SPIOperations
+type Connection Operations
 
 type SpiConnection struct {
-	bus      SPIDevice
+	Connection
+	port     xspi.PortCloser
+	dev      xspi.Conn
+	bus      int
+	chip     int
+	bits     int
 	mode     int
 	maxSpeed int64
 }
 
 // NewConnection creates and returns a new connection to a specific
-// spi device on a bus and address
-func NewConnection(bus SPIDevice) (connection *SpiConnection) {
-	return &SpiConnection{bus: bus}
+// spi device on a bus/chip using the periph.io interface
+func NewConnection(port xspi.PortCloser, conn xspi.Conn) (connection *SpiConnection) {
+	return &SpiConnection{port: port, dev: conn}
 }
 
+// Close the SPI connection
 func (c *SpiConnection) Close() error {
-	return c.bus.Close()
-}
-
-func (c *SpiConnection) SetBitOrder(o xspi.Order) error {
-	return c.bus.SetBitOrder(o)
-}
-
-func (c *SpiConnection) SetBitsPerWord(bits int) error {
-	return c.bus.SetBitsPerWord(bits)
-}
-
-func (c *SpiConnection) SetCSChange(leaveEnabled bool) error {
-	return c.bus.SetCSChange(leaveEnabled)
-}
-
-func (c *SpiConnection) SetDelay(t time.Duration) error {
-	return c.bus.SetDelay(t)
-}
-
-func (c *SpiConnection) SetMaxSpeed(speed int) error {
-	return c.bus.SetMaxSpeed(speed)
-}
-
-func (c *SpiConnection) SetMode(mode xspi.Mode) error {
-	return c.bus.SetMode(mode)
+	return c.port.Close()
 }
 
+// Tx uses the SPI device to send/receive data.
 func (c *SpiConnection) Tx(w, r []byte) error {
-	return c.bus.Tx(w, r)
+	return c.dev.Tx(w, r)
 }
 
-// GetSPIBus is a helper to return a SPI bus
-func GetSpiBus(busNum, mode int, maxSpeed int64) (spiDevice SPIDevice, err error) {
+// GetSpiConnection is a helper to return a SPI device
+func GetSpiConnection(busNum, chipNum, mode, bits int, maxSpeed int64) (spiDevice Device, err error) {
+	if _, err := host.Init(); err != nil {
+		log.Fatal(err)
+	}
+
 	var spiMode xspi.Mode
 	switch mode {
 	case 0:
@@ -112,17 +102,17 @@ func GetSpiBus(busNum, mode int, maxSpeed int64) (spiDevice SPIDevice, err error
 	default:
 		spiMode = xspi.Mode0
 	}
-	dev := fmt.Sprintf("/dev/spidev0.%d", busNum)
-	devfs := &xspi.Devfs{
-		Dev:      dev,
-		Mode:     spiMode,
-		MaxSpeed: maxSpeed,
+	devName := fmt.Sprintf("/dev/spidev%d.%d", busNum, chipNum)
+	p, err := spireg.Open(devName)
+	if err != nil {
+		return nil, err
 	}
-	bus, err := xspi.Open(devfs)
+
+	c, err := p.Connect(maxSpeed, spiMode, bits)
 	if err != nil {
 		return nil, err
 	}
-	spiDevice = NewConnection(bus)
+	spiDevice = NewConnection(p, c)
 
 	return
 }