i2c: ensure all current i2c drivers (except for wiichuck) use a standard i2c style request/response interaction pattern

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

drivers/i2c/mpl115a2_driver.go

@@ -29,7 +29,6 @@ type MPL115A2Driver struct {
 	connector  Connector
 	connection Connection
 	Config
-	interval time.Duration
 	gobot.Eventer
 	A0          float32
 	B1          float32
@@ -39,7 +38,9 @@ type MPL115A2Driver struct {
 	Temperature float32
 }
 
-// NewMPL115A2Driver creates a new driver with specified i2c interface
+// NewMPL115A2Driver creates a new Gobot Driver for an MPL115A2
+// I2C Pressure/Temperature sensor.
+//
 // Params:
 //		conn Connector - the Adaptor to use with this Driver
 //
@@ -53,7 +54,6 @@ func NewMPL115A2Driver(a Connector, options ...func(Config)) *MPL115A2Driver {
 		connector: a,
 		Config:    NewConfig(),
 		Eventer:   gobot.NewEventer(),
-		interval:  10 * time.Millisecond,
 	}
 
 	for _, option := range options {
@@ -78,55 +78,53 @@ func (h *MPL115A2Driver) Connection() gobot.Connection { return h.connector.(gob
 // Start writes initialization bytes and reads from adaptor
 // using specified interval to accelerometer andtemperature data
 func (h *MPL115A2Driver) Start() (err error) {
-	var temperature uint16
-	var pressure uint16
-	var pressureComp float32
-
 	if err := h.initialization(); err != nil {
 		return err
 	}
 
-	go func() {
-		for {
-			if _, err := h.connection.Write([]byte{MPL115A2_REGISTER_STARTCONVERSION, 0}); err != nil {
-				h.Publish(h.Event(Error), err)
-				continue
-
-			}
-			time.Sleep(5 * time.Millisecond)
-
-			if _, err := h.connection.Write([]byte{MPL115A2_REGISTER_PRESSURE_MSB}); err != nil {
-				h.Publish(h.Event(Error), err)
-				continue
-			}
-
-			data := []byte{0, 0, 0, 0}
-			bytesRead, err := h.connection.Read(data)
-			if err != nil {
-				h.Publish(h.Event(Error), err)
-				continue
-			}
-			if bytesRead == 4 {
-				buf := bytes.NewBuffer(data)
-				binary.Read(buf, binary.BigEndian, &pressure)
-				binary.Read(buf, binary.BigEndian, &temperature)
-
-				temperature = temperature >> 6
-				pressure = pressure >> 6
-
-				pressureComp = float32(h.A0) + (float32(h.B1)+float32(h.C12)*float32(temperature))*float32(pressure) + float32(h.B2)*float32(temperature)
-				h.Pressure = (65.0/1023.0)*pressureComp + 50.0
-				h.Temperature = ((float32(temperature) - 498.0) / -5.35) + 25.0
-			}
-			time.Sleep(h.interval)
-		}
-	}()
 	return
 }
 
 // Halt returns true if devices is halted successfully
 func (h *MPL115A2Driver) Halt() (err error) { return }
 
+// GetData fetches the latest data from the MPL115A2
+func (h *MPL115A2Driver) GetData() error {
+	var temperature uint16
+	var pressure uint16
+	var pressureComp float32
+
+	if _, err := h.connection.Write([]byte{MPL115A2_REGISTER_STARTCONVERSION, 0}); err != nil {
+		return err
+	}
+	time.Sleep(5 * time.Millisecond)
+
+	if _, err := h.connection.Write([]byte{MPL115A2_REGISTER_PRESSURE_MSB}); err != nil {
+		return err
+	}
+
+	data := []byte{0, 0, 0, 0}
+	bytesRead, err := h.connection.Read(data)
+	if err != nil {
+		return err
+	}
+
+	if bytesRead == 4 {
+		buf := bytes.NewBuffer(data)
+		binary.Read(buf, binary.BigEndian, &pressure)
+		binary.Read(buf, binary.BigEndian, &temperature)
+
+		temperature = temperature >> 6
+		pressure = pressure >> 6
+
+		pressureComp = float32(h.A0) + (float32(h.B1)+float32(h.C12)*float32(temperature))*float32(pressure) + float32(h.B2)*float32(temperature)
+		h.Pressure = (65.0/1023.0)*pressureComp + 50.0
+		h.Temperature = ((float32(temperature) - 498.0) / -5.35) + 25.0
+	}
+
+	return nil
+}
+
 func (h *MPL115A2Driver) initialization() (err error) {
 	var coA0 int16
 	var coB1 int16

drivers/i2c/mpl115a2_driver_test.go

@@ -3,7 +3,6 @@ package i2c
 import (
 	"strings"
 	"testing"
-	"time"
 
 	"gobot.io/x/gobot"
 	"gobot.io/x/gobot/gobottest"
@@ -42,14 +41,20 @@ func TestMPL115A2Driver(t *testing.T) {
 }
 
 func TestMPL115A2DriverStart(t *testing.T) {
+	mpl, _ := initTestMPL115A2DriverWithStubbedAdaptor()
+
+	gobottest.Assert(t, mpl.Start(), nil)
+}
+
+func TestMPL115A2DriverReadData(t *testing.T) {
 	mpl, adaptor := initTestMPL115A2DriverWithStubbedAdaptor()
 
 	adaptor.i2cReadImpl = func(b []byte) (int, error) {
 		copy(b, []byte{0x00, 0x01, 0x02, 0x04})
 		return 4, nil
 	}
-	gobottest.Assert(t, mpl.Start(), nil)
+	mpl.Start()
-	time.Sleep(100 * time.Millisecond)
+	mpl.GetData()
 	gobottest.Assert(t, mpl.Pressure, float32(50.007942))
 	gobottest.Assert(t, mpl.Temperature, float32(116.58878))
 }

drivers/i2c/mpu6050_driver.go

@@ -44,7 +44,8 @@ type MPU6050Driver struct {
 	gobot.Eventer
 }
 
-// NewMPU6050Driver creates a new driver with specified i2c interface
+// NewMPU6050Driver creates a new Gobot Driver for an MPU6050 I2C Accelerometer/Gyroscope.
+//
 // Params:
 //		conn Connector - the Adaptor to use with this Driver
 //
@@ -57,7 +58,6 @@ func NewMPU6050Driver(a Connector, options ...func(Config)) *MPU6050Driver {
 		name:      gobot.DefaultName("MPU6050"),
 		connector: a,
 		Config:    NewConfig(),
-		interval:  10 * time.Millisecond,
 		Eventer:   gobot.NewEventer(),
 	}
 
@@ -66,8 +66,6 @@ func NewMPU6050Driver(a Connector, options ...func(Config)) *MPU6050Driver {
 	}
 
 	// TODO: add commands to API
-
-	m.AddEvent(Error)
 	return m
 }
 
@@ -80,40 +78,38 @@ func (h *MPU6050Driver) SetName(n string) { h.name = n }
 // Connection returns the connection for the device.
 func (h *MPU6050Driver) Connection() gobot.Connection { return h.connector.(gobot.Connection) }
 
-// Start writes initialization bytes and reads from adaptor
+// Start writes initialization bytes to sensor
-// using specified interval to accelerometer andtemperature data
 func (h *MPU6050Driver) Start() (err error) {
 	if err := h.initialize(); err != nil {
 		return err
 	}
 
-	go func() {
-		for {
-			if _, err := h.connection.Write([]byte{MPU6050_RA_ACCEL_XOUT_H}); err != nil {
-				h.Publish(h.Event(Error), err)
-				continue
-			}
-
-			data := make([]byte, 14)
-			_, err := h.connection.Read(data)
-			if err != nil {
-				h.Publish(h.Event(Error), err)
-				continue
-			}
-			buf := bytes.NewBuffer(data)
-			binary.Read(buf, binary.BigEndian, &h.Accelerometer)
-			binary.Read(buf, binary.BigEndian, &h.Temperature)
-			binary.Read(buf, binary.BigEndian, &h.Gyroscope)
-			h.convertToCelsius()
-			time.Sleep(h.interval)
-		}
-	}()
 	return
 }
 
 // Halt returns true if devices is halted successfully
 func (h *MPU6050Driver) Halt() (err error) { return }
 
+// GetData fetches the latest data from the MPU6050
+func (h *MPU6050Driver) GetData() (err error) {
+	if _, err = h.connection.Write([]byte{MPU6050_RA_ACCEL_XOUT_H}); err != nil {
+		return
+	}
+
+	data := make([]byte, 14)
+	_, err = h.connection.Read(data)
+	if err != nil {
+		return
+	}
+
+	buf := bytes.NewBuffer(data)
+	binary.Read(buf, binary.BigEndian, &h.Accelerometer)
+	binary.Read(buf, binary.BigEndian, &h.Temperature)
+	binary.Read(buf, binary.BigEndian, &h.Gyroscope)
+	h.convertToCelsius()
+	return
+}
+
 func (h *MPU6050Driver) initialize() (err error) {
 	bus := h.GetBusOrDefault(h.connector.GetDefaultBus())
 	address := h.GetAddressOrDefault(mpu6050Address)

drivers/i2c/mpu6050_driver_test.go

@@ -3,7 +3,6 @@ package i2c
 import (
 	"strings"
 	"testing"
-	"time"
 
 	"gobot.io/x/gobot"
 	"gobot.io/x/gobot/gobottest"
@@ -36,7 +35,6 @@ func TestNewMPU6050Driver(t *testing.T) {
 func TestMPU6050Driver(t *testing.T) {
 	mpu := initTestMPU6050Driver()
 	gobottest.Refute(t, mpu.Connection(), nil)
-	gobottest.Assert(t, mpu.interval, 10*time.Millisecond)
 
 	mpu = NewMPU6050Driver(newI2cTestAdaptor(), WithBus(2))
 	gobottest.Assert(t, mpu.GetBusOrDefault(1), 2)
@@ -57,3 +55,15 @@ func TestMPU6050DriverHalt(t *testing.T) {
 
 	gobottest.Assert(t, mpu.Halt(), nil)
 }
+
+func TestMPU6050DriverReadData(t *testing.T) {
+	mpu, adaptor := initTestMPU6050DriverWithStubbedAdaptor()
+
+	adaptor.i2cReadImpl = func(b []byte) (int, error) {
+		copy(b, []byte{0x00, 0x01, 0x02, 0x04})
+		return 4, nil
+	}
+	mpu.Start()
+	mpu.GetData()
+	gobottest.Assert(t, mpu.Temperature, int16(36))
+}

examples/chip_mpu6050.go

@@ -15,6 +15,8 @@ func main() {
 
 	work := func() {
 		gobot.Every(100*time.Millisecond, func() {
+			mpu6050.GetData()
+
 			fmt.Println("Accelerometer", mpu6050.Accelerometer)
 			fmt.Println("Gyroscope", mpu6050.Gyroscope)
 			fmt.Println("Temperature", mpu6050.Temperature)

examples/firmata_mpl115a2.go

@@ -15,6 +15,8 @@ func main() {
 
 	work := func() {
 		gobot.Every(1*time.Second, func() {
+			mpl115a2.GetData()
+
 			fmt.Println("Pressure", mpl115a2.Pressure)
 			fmt.Println("Temperature", mpl115a2.Temperature)
 		})

examples/firmata_mpu6050.go

@@ -15,6 +15,8 @@ func main() {
 
 	work := func() {
 		gobot.Every(100*time.Millisecond, func() {
+			mpu6050.GetData()
+
 			fmt.Println("Accelerometer", mpu6050.Accelerometer)
 			fmt.Println("Gyroscope", mpu6050.Gyroscope)
 			fmt.Println("Temperature", mpu6050.Temperature)