gpio: Add ButtonDriver.DefaultState to allow for 'reverse' buttons (o…

…nes that go from HIGH to LOW)

Signed-off-by: deadprogram <[email protected]>

drivers/gpio/button_driver.go

@@ -8,12 +8,13 @@ import (
 
 // ButtonDriver Represents a digital Button
 type ButtonDriver struct {
-	Active     bool
-	pin        string
-	name       string
-	halt       chan bool
-	interval   time.Duration
-	connection DigitalReader
+	Active       bool
+	DefaultState int
+	pin          string
+	name         string
+	halt         chan bool
+	interval     time.Duration
+	connection   DigitalReader
 	gobot.Eventer
 }
 
@@ -24,13 +25,14 @@ type ButtonDriver struct {
 //  time.Duration: Interval at which the ButtonDriver is polled for new information
 func NewButtonDriver(a DigitalReader, pin string, v ...time.Duration) *ButtonDriver {
 	b := &ButtonDriver{
-		name:       gobot.DefaultName("Button"),
-		connection: a,
-		pin:        pin,
-		Active:     false,
-		Eventer:    gobot.NewEventer(),
-		interval:   10 * time.Millisecond,
-		halt:       make(chan bool),
+		name:         gobot.DefaultName("Button"),
+		connection:   a,
+		pin:          pin,
+		Active:       false,
+		DefaultState: 0,
+		Eventer:      gobot.NewEventer(),
+		interval:     10 * time.Millisecond,
+		halt:         make(chan bool),
 	}
 
 	if len(v) > 0 {
@@ -51,7 +53,7 @@ func NewButtonDriver(a DigitalReader, pin string, v ...time.Duration) *ButtonDri
 //	Release int - On button release
 //	Error error - On button error
 func (b *ButtonDriver) Start() (err error) {
-	state := 0
+	state := b.DefaultState
 	go func() {
 		for {
 			newValue, err := b.connection.DigitalRead(b.Pin())
@@ -90,7 +92,7 @@ func (b *ButtonDriver) Pin() string { return b.pin }
 func (b *ButtonDriver) Connection() gobot.Connection { return b.connection.(gobot.Connection) }
 
 func (b *ButtonDriver) update(newValue int) {
-	if newValue == 1 {
+	if newValue != b.DefaultState {
 		b.Active = true
 		b.Publish(ButtonPush, newValue)
 	} else {

drivers/gpio/button_driver_test.go

@@ -106,6 +106,47 @@ func TestButtonDriverStart(t *testing.T) {
 	}
 }
 
+func TestButtonDriverDefaultState(t *testing.T) {
+	sem := make(chan bool, 0)
+	a := newGpioTestAdaptor()
+	d := NewButtonDriver(a, "1")
+	d.DefaultState = 1
+
+	d.Once(ButtonPush, func(data interface{}) {
+		gobottest.Assert(t, d.Active, true)
+		sem <- true
+	})
+
+	a.TestAdaptorDigitalRead(func() (val int, err error) {
+		val = 0
+		return
+	})
+
+	gobottest.Assert(t, d.Start(), nil)
+
+	select {
+	case <-sem:
+	case <-time.After(buttonTestDelay * time.Millisecond):
+		t.Errorf("Button Event \"Push\" was not published")
+	}
+
+	d.Once(ButtonRelease, func(data interface{}) {
+		gobottest.Assert(t, d.Active, false)
+		sem <- true
+	})
+
+	a.TestAdaptorDigitalRead(func() (val int, err error) {
+		val = 1
+		return
+	})
+
+	select {
+	case <-sem:
+	case <-time.After(buttonTestDelay * time.Millisecond):
+		t.Errorf("Button Event \"Release\" was not published")
+	}
+}
+
 func TestButtonDriverDefaultName(t *testing.T) {
 	g := initTestButtonDriver()
 	gobottest.Assert(t, strings.HasPrefix(g.Name(), "Button"), true)