core: some WIP on using digitalread and analogread event subscriptions for all gpio drivers

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

drivers/gpio/analog_sensor_driver.go

@@ -12,7 +12,7 @@ type AnalogSensorDriver struct {
 	pin        string
 	halt       chan bool
 	interval   time.Duration
-	connection AnalogReader
+	connection AnalogReadEventer
 	gobot.Eventer
 	gobot.Commander
 }
@@ -25,7 +25,7 @@ type AnalogSensorDriver struct {
 //
 // Adds the following API Commands:
 // 	"Read" - See AnalogSensor.Read
-func NewAnalogSensorDriver(a AnalogReader, pin string, v ...time.Duration) *AnalogSensorDriver {
+func NewAnalogSensorDriver(a AnalogReadEventer, pin string, v ...time.Duration) *AnalogSensorDriver {
 	d := &AnalogSensorDriver{
 		name:       "AnalogSensor",
 		connection: a,
@@ -56,25 +56,18 @@ func NewAnalogSensorDriver(a AnalogReader, pin string, v ...time.Duration) *Anal
 //	Data int - Event is emitted on change and represents the current reading from the sensor.
 //	Error error - Event is emitted on error reading from the sensor.
 func (a *AnalogSensorDriver) Start() (err error) {
-	value := 0
-	go func() {
-		timer := time.NewTimer(a.interval)
-		timer.Stop()
-		for {
-			newValue, err := a.Read()
-			if err != nil {
-				a.Publish(a.Event(Error), err)
-			} else if newValue != value && newValue != -1 {
-				value = newValue
-				a.Publish(a.Event(Data), value)
-			}
+	evts := a.connection.SubscribeAnalogRead(a.Pin())
 
-			timer.Reset(a.interval)
+	go func() {
+		analogread := "analogread-" + a.Pin()
+		for {
 			select {
-			case <-timer.C:
 			case <-a.halt:
-				timer.Stop()
 				return
+			case evt := <-evts:
+				if evt.Name == analogread {
+					a.Publish(Data, evt.Data)
+				}
 			}
 		}
 	}()

drivers/gpio/gpio.go

@@ -73,3 +73,17 @@ type DigitalReader interface {
 	gobot.Adaptor
 	DigitalRead(string) (val int, err error)
 }
+
+// DigitalReadEventer interface represents an Adaptor which has SubscribeDigitalRead capabilities
+type DigitalReadEventer interface {
+	gobot.Eventer
+	DigitalReader
+	SubscribeDigitalRead(string) (gobot.EventChannel)
+}
+
+// AnalogReadEventer interface represents an Adaptor which has SubscribeAnalogRead capabilities
+type AnalogReadEventer interface {
+	gobot.Eventer
+	AnalogReader
+	SubscribeAnalogRead(string) (gobot.EventChannel)
+}

drivers/gpio/grove_drivers.go

@@ -34,7 +34,7 @@ type GroveRotaryDriver struct {
 //
 // Adds the following API Commands:
 // 	"Read" - See AnalogSensor.Read
-func NewGroveRotaryDriver(a AnalogReader, pin string, v ...time.Duration) *GroveRotaryDriver {
+func NewGroveRotaryDriver(a AnalogReadEventer, pin string, v ...time.Duration) *GroveRotaryDriver {
 	return &GroveRotaryDriver{
 		AnalogSensorDriver: NewAnalogSensorDriver(a, pin, v...),
 	}
@@ -72,7 +72,7 @@ type GroveLightSensorDriver struct {
 //
 // Adds the following API Commands:
 // 	"Read" - See AnalogSensor.Read
-func NewGroveLightSensorDriver(a AnalogReader, pin string, v ...time.Duration) *GroveLightSensorDriver {
+func NewGroveLightSensorDriver(a AnalogReadEventer, pin string, v ...time.Duration) *GroveLightSensorDriver {
 	return &GroveLightSensorDriver{
 		AnalogSensorDriver: NewAnalogSensorDriver(a, pin, v...),
 	}
@@ -92,7 +92,7 @@ type GrovePiezoVibrationSensorDriver struct {
 //
 // Adds the following API Commands:
 // 	"Read" - See AnalogSensor.Read
-func NewGrovePiezoVibrationSensorDriver(a AnalogReader, pin string, v ...time.Duration) *GrovePiezoVibrationSensorDriver {
+func NewGrovePiezoVibrationSensorDriver(a AnalogReadEventer, pin string, v ...time.Duration) *GrovePiezoVibrationSensorDriver {
 	sensor := &GrovePiezoVibrationSensorDriver{
 		AnalogSensorDriver: NewAnalogSensorDriver(a, pin, v...),
 	}
@@ -152,7 +152,7 @@ type GroveSoundSensorDriver struct {
 //
 // Adds the following API Commands:
 // 	"Read" - See AnalogSensor.Read
-func NewGroveSoundSensorDriver(a AnalogReader, pin string, v ...time.Duration) *GroveSoundSensorDriver {
+func NewGroveSoundSensorDriver(a AnalogReadEventer, pin string, v ...time.Duration) *GroveSoundSensorDriver {
 	return &GroveSoundSensorDriver{
 		AnalogSensorDriver: NewAnalogSensorDriver(a, pin, v...),
 	}

eventer.go

@@ -2,17 +2,17 @@ package gobot
 
 import "sync"
 
-type eventChannel chan *Event
+type EventChannel chan *Event
 
 type eventer struct {
 	// map of valid Event names
 	eventnames map[string]string
 
 	// new events get put in to the event channel
-	in eventChannel
+	in EventChannel
 
 	// map of out channels used by subscribers
-	outs map[eventChannel]eventChannel
+	outs map[EventChannel]EventChannel
 
 	// mutex to protect the eventChannel map
 	eventsMutex sync.Mutex
@@ -38,10 +38,10 @@ type Eventer interface {
 	Publish(name string, data interface{})
 
 	// Subscribe to events
-	Subscribe() (events eventChannel)
+	Subscribe() (events EventChannel)
 
 	// Unsubscribe from an event channel
-	Unsubscribe(events eventChannel)
+	Unsubscribe(events EventChannel)
 
 	// Event handler
 	On(name string, f func(s interface{})) (err error)
@@ -54,8 +54,8 @@ type Eventer interface {
 func NewEventer() Eventer {
 	evtr := &eventer{
 		eventnames: make(map[string]string),
-		in:         make(eventChannel, 1),
-		outs:       make(map[eventChannel]eventChannel),
+		in:         make(EventChannel, 1),
+		outs:       make(map[EventChannel]EventChannel),
 	}
 
 	// goroutine to cascade "in" events to all "out" event channels
@@ -103,16 +103,16 @@ func (e *eventer) Publish(name string, data interface{}) {
 }
 
 // Subscribe to any events from this eventer
-func (e *eventer) Subscribe() eventChannel {
+func (e *eventer) Subscribe() EventChannel {
 	e.eventsMutex.Lock()
 	defer e.eventsMutex.Unlock()
-	out := make(eventChannel)
+	out := make(EventChannel)
 	e.outs[out] = out
 	return out
 }
 
 // Unsubscribe from the event channel
-func (e *eventer) Unsubscribe(events eventChannel) {
+func (e *eventer) Unsubscribe(events EventChannel) {
 	e.eventsMutex.Lock()
 	defer e.eventsMutex.Unlock()
 	delete(e.outs, events)

examples/beaglebone_analog.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"fmt"
+
+	"gobot.io/x/gobot"
+	"gobot.io/x/gobot/drivers/gpio"
+	"gobot.io/x/gobot/platforms/beaglebone"
+)
+
+func main() {
+	a := beaglebone.NewAdaptor()
+	sensor := gpio.NewAnalogSensorDriver(a, "P9_39")
+
+	work := func() {
+		sensor.On(gpio.Data, func(data interface{}) {
+			voltage := (float64(data.(int)) * 1.8) / 1024 // BBB uses 1.8V
+			tempC := (voltage - 0.5) * 100
+			tempF := (tempC * 9 / 5) + 32
+
+			fmt.Printf("%.2f°C\n", tempC)
+			fmt.Printf("%.2f°F\n", tempF)
+		})
+	}
+
+	robot := gobot.NewRobot("sensorBot",
+		[]gobot.Connection{a},
+		[]gobot.Device{sensor},
+		work,
+	)
+
+	robot.Start()
+}

platforms/beaglebone/beaglebone_adaptor.go

@@ -9,10 +9,12 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"time"
 
 	multierror "github.com/hashicorp/go-multierror"
 	"gobot.io/x/gobot"
 	"gobot.io/x/gobot/sysfs"
+	"gobot.io/x/gobot/drivers/gpio"
 )
 
 var glob = func(pattern string) (matches []string, err error) {
@@ -31,6 +33,9 @@ type Adaptor struct {
 	analogPath   string
 	analogPinMap map[string]string
 	slots        string
+	interval   time.Duration
+	halt       chan bool
+	gobot.Eventer
 }
 
 // NewAdaptor returns a new Beaglebone Adaptor
@@ -39,6 +44,8 @@ func NewAdaptor() *Adaptor {
 		name:        "Beaglebone",
 		digitalPins: make([]sysfs.DigitalPin, 120),
 		pwmPins:     make(map[string]*pwmPin),
+		interval:   10 * time.Millisecond,
+		halt:       make(chan bool),
 	}
 
 	b.setSlots()
@@ -195,6 +202,68 @@ func (b *Adaptor) AnalogRead(pin string) (val int, err error) {
 	return
 }
 
+// SubscribeDigitalRead starts reading from the specified pin,
+// and publishes events on the returned event channel when changes occur
+func (b *Adaptor) SubscribeDigitalRead(pin string) (gobot.EventChannel) {
+	// TODO: replace with epoll based implementation
+	b.AddEvent("digitalread-" + pin)
+	value := 0
+	go func() {
+		timer := time.NewTimer(b.interval)
+		timer.Stop()
+		for {
+			newValue, err := b.DigitalRead(pin)
+			if err != nil {
+				b.Publish(b.Event(gpio.Error), err)
+			} else if newValue != value && newValue != -1 {
+				value = newValue
+				b.Publish(b.Event("digitalread-" + pin), value)
+			}
+
+			timer.Reset(b.interval)
+			select {
+			case <-timer.C:
+			case <-b.halt:
+				timer.Stop()
+				return
+			}
+		}
+	}()
+
+	return b.Subscribe()
+}
+
+// SubscribeAnalogRead starts reading from the specified pin,
+// and publishes events on the returned event channel when changes occur
+func (b *Adaptor) SubscribeAnalogRead(pin string) (gobot.EventChannel) {
+	// TODO: replace with epoll based implementation
+	b.AddEvent("analogread-" + pin)
+	value := 0
+	go func() {
+		timer := time.NewTimer(b.interval)
+		timer.Stop()
+		for {
+			newValue, err := b.AnalogRead(pin)
+			if err != nil {
+				b.Publish(b.Event(gpio.Error), err)
+			} else if newValue != value && newValue != -1 {
+				value = newValue
+				b.Publish(b.Event("analogread-" + pin), value)
+			}
+
+			timer.Reset(b.interval)
+			select {
+			case <-timer.C:
+			case <-b.halt:
+				timer.Stop()
+				return
+			}
+		}
+	}()
+
+	return b.Subscribe()
+}
+
 // I2cStart starts a i2c device in specified address on i2c bus /dev/i2c-1
 func (b *Adaptor) I2cStart(address int) (err error) {
 	if b.i2cDevice == nil {