beaglebone: add SPI support and remove last vestiges of slots

Signed-off-by: deadprogram <ron@hybridgroup.com>

platforms/beaglebone/beaglebone_adaptor.go

@@ -1,7 +1,6 @@
 package beaglebone
 
 import (
-	"bufio"
 	"errors"
 	"fmt"
 	"os"
@@ -13,6 +12,7 @@ import (
 	multierror "github.com/hashicorp/go-multierror"
 	"gobot.io/x/gobot"
 	"gobot.io/x/gobot/drivers/i2c"
+	"gobot.io/x/gobot/drivers/spi"
 	"gobot.io/x/gobot/sysfs"
 )
 
@@ -31,12 +31,15 @@ type Adaptor struct {
 	i2cBuses           map[int]i2c.I2cDevice
 	usrLed             string
 	analogPath         string
-	slots        string
 	pinMap             map[string]int
 	pwmPinMap          map[string]pwmPinData
 	analogPinMap       map[string]string
 	mutex              *sync.Mutex
 	findPin            func(pinPath string) (string, error)
+	spiDefaultBus      int
+	spiBuses           [2]spi.SPIDevice
+	spiDefaultMode     int
+	spiDefaultMaxSpeed int64
 }
 
 // NewAdaptor returns a new Beaglebone Black/Green Adaptor
@@ -61,9 +64,12 @@ func NewAdaptor() *Adaptor {
 }
 
 func (b *Adaptor) setPaths() {
-	b.slots = "/sys/devices/platform/bone_capemgr/slots"
 	b.usrLed = "/sys/class/leds/beaglebone:green:"
 	b.analogPath = "/sys/bus/iio/devices/iio:device0"
+
+	b.spiDefaultBus = 0
+	b.spiDefaultMode = 0
+	b.spiDefaultMaxSpeed = 500000
 }
 
 // Name returns the Adaptor name
@@ -103,6 +109,13 @@ func (b *Adaptor) Finalize() (err error) {
 			}
 		}
 	}
+	for _, bus := range b.spiBuses {
+		if bus != nil {
+			if e := bus.Close(); e != nil {
+				err = multierror.Append(err, e)
+			}
+		}
+	}
 	return
 }
 
@@ -267,6 +280,38 @@ func (b *Adaptor) GetDefaultBus() int {
 	return 2
 }
 
+// GetSpiConnection returns an spi connection to a device on a specified bus.
+// Valid bus number is [0..1] which corresponds to /dev/spidev0.0 through /dev/spidev0.1.
+func (b *Adaptor) GetSpiConnection(busNum, mode int, maxSpeed int64) (connection spi.Connection, err error) {
+	b.mutex.Lock()
+	defer b.mutex.Unlock()
+
+	if (busNum < 0) || (busNum > 1) {
+		return nil, fmt.Errorf("Bus number %d out of range", busNum)
+	}
+
+	if b.spiBuses[busNum] == nil {
+		b.spiBuses[busNum], err = spi.GetSpiBus(busNum, mode, maxSpeed)
+	}
+
+	return spi.NewConnection(b.spiBuses[busNum]), err
+}
+
+// GetSpiDefaultBus returns the default spi bus for this platform.
+func (b *Adaptor) GetSpiDefaultBus() int {
+	return b.spiDefaultBus
+}
+
+// GetSpiDefaultMode returns the default spi mode for this platform.
+func (b *Adaptor) GetSpiDefaultMode() int {
+	return b.spiDefaultMode
+}
+
+// GetSpiDefaultMaxSpeed returns the default spi bus for this platform.
+func (b *Adaptor) GetSpiDefaultMaxSpeed() int64 {
+	return b.spiDefaultMaxSpeed
+}
+
 // translatePin converts digital pin name to pin position
 func (b *Adaptor) translatePin(pin string) (value int, err error) {
 	if val, ok := b.pinMap[pin]; ok {
@@ -296,39 +341,6 @@ func (b *Adaptor) translateAnalogPin(pin string) (value string, err error) {
 	return
 }
 
-func ensureSlot(slots, item string) (err error) {
-	fi, err := sysfs.OpenFile(slots, os.O_RDWR|os.O_APPEND, 0666)
-	defer fi.Close()
-	if err != nil {
-		return
-	}
-
-	// ensure the slot is not already written into the capemanager
-	// (from: https://github.com/mrmorphic/hwio/blob/master/module_bb_pwm.go#L190)
-	scanner := bufio.NewScanner(fi)
-	for scanner.Scan() {
-		line := scanner.Text()
-		if strings.Index(line, item) > 0 {
-			return
-		}
-	}
-
-	_, err = fi.WriteString(item)
-	if err != nil {
-		return err
-	}
-	fi.Sync()
-
-	scanner = bufio.NewScanner(fi)
-	for scanner.Scan() {
-		line := scanner.Text()
-		if strings.Index(line, item) > 0 {
-			return
-		}
-	}
-	return
-}
-
 func muxPin(pin, cmd string) error {
 	path := fmt.Sprintf("/sys/devices/platform/ocp/ocp:%s_pinmux/state", pin)
 	fi, e := sysfs.OpenFile(path, os.O_WRONLY, 0666)

platforms/beaglebone/beaglebone_adaptor_test.go

@@ -9,6 +9,7 @@ import (
 	"gobot.io/x/gobot/drivers/aio"
 	"gobot.io/x/gobot/drivers/gpio"
 	"gobot.io/x/gobot/drivers/i2c"
+	"gobot.io/x/gobot/drivers/spi"
 	"gobot.io/x/gobot/gobottest"
 	"gobot.io/x/gobot/sysfs"
 )
@@ -23,6 +24,7 @@ var _ gpio.ServoWriter = (*Adaptor)(nil)
 var _ sysfs.DigitalPinnerProvider = (*Adaptor)(nil)
 var _ sysfs.PWMPinnerProvider = (*Adaptor)(nil)
 var _ i2c.Connector = (*Adaptor)(nil)
+var _ spi.Connector = (*Adaptor)(nil)
 
 func initBBBTestAdaptor() (*Adaptor, error) {
 	a := NewAdaptor()
@@ -50,7 +52,6 @@ func TestBeagleboneAdaptor(t *testing.T) {
 	fs := sysfs.NewMockFilesystem([]string{
 		"/dev/i2c-2",
 		"/sys/devices/platform/bone_capemgr",
-		"/sys/devices/platform/bone_capemgr/slots",
 		"/sys/devices/platform/ocp/ocp:P8_7_pinmux/state",
 		"/sys/devices/platform/ocp/ocp:P9_11_pinmux/state",
 		"/sys/devices/platform/ocp/ocp:P9_12_pinmux/state",
@@ -199,19 +200,9 @@ func TestBeagleboneGetConnectionInvalidBus(t *testing.T) {
 	gobottest.Assert(t, err, errors.New("Bus number 99 out of range"))
 }
 
-func TestBeagleboneConnectNoSlot(t *testing.T) {
-	fs := sysfs.NewMockFilesystem([]string{
-		"/dev/i2c-2",
-	})
-	sysfs.SetFilesystem(fs)
-
-	_, err := initBBBTestAdaptor()
-	gobottest.Assert(t, strings.Contains(err.Error(), "/sys/devices/platform/bone_capemgr/slots: No such file."), true)
-}
-
 func TestBeagleboneAnalogReadFileError(t *testing.T) {
 	fs := sysfs.NewMockFilesystem([]string{
-		"/sys/devices/platform/bone_capemgr/slots",
+		"/sys/devices/platform/whatever",
 	})
 	sysfs.SetFilesystem(fs)