gpio(hcsr04): add driver for ultrasonic ranging module (#1012)

README.md

@@ -270,7 +270,7 @@ Support for many devices that use General Purpose Input/Output (GPIO) have
 a shared set of drivers provided using the `gobot/drivers/gpio` package:
 
 - [GPIO](https://en.wikipedia.org/wiki/General_Purpose_Input/Output) <=> [Drivers](https://github.com/hybridgroup/gobot/tree/master/drivers/gpio)
-  - AIP1640 LED
+  - AIP1640 LED Dot Matrix/7 Segment Controller
   - Button
   - Buzzer
   - Direct Pin
@@ -281,8 +281,11 @@ a shared set of drivers provided using the `gobot/drivers/gpio` package:
   - Grove Magnetic Switch
   - Grove Relay
   - Grove Touch Sensor
+  - HC-SR04 Ultrasonic Ranging Module
+  - HD44780 LCD controller
   - LED
   - Makey Button
+  - MAX7219 LED Dot Matrix
   - Motor
   - Proximity Infra Red (PIR) Motion Sensor
   - Relay

appveyor.yml

@@ -15,10 +15,9 @@ before_test:
 build_script:
   - go test -v -cpu=2 .
   - go test -v -cpu=2 ./drivers/aio/...
-  - go test -v -cpu=2 ./drivers/i2c/...
+  - go test -v -cpu=2 ./platforms/ble/...
   - go test -v -cpu=2 ./platforms/dji/...
   - go test -v -cpu=2 ./platforms/firmata/...
-  - go test -v -cpu=2 ./platforms/ble/...
   - go test -v -cpu=2 ./platforms/joystick/...
   - go test -v -cpu=2 ./platforms/parrot/...
   - go test -v -cpu=2 ./platforms/sphero/...

drivers/gpio/README.md

@@ -12,23 +12,26 @@ Please refer to the main [README.md](https://github.com/hybridgroup/gobot/blob/r
 
 Gobot has a extensible system for connecting to hardware devices. The following GPIO devices are currently supported:
 
+- AIP1640 LED Dot Matrix/7 Segment Controller
 - Button
 - Buzzer
 - Direct Pin
+- EasyDriver
 - Grove Button
 - Grove Buzzer
 - Grove LED
 - Grove Magnetic Switch
 - Grove Relay
 - Grove Touch Sensor
+- HC-SR04 Ultrasonic Ranging Module
+- HD44780 LCD controller
 - LED
 - Makey Button
+- MAX7219 LED Dot Matrix
 - Motor
 - Proximity Infra Red (PIR) Motion Sensor
 - Relay
 - RGB LED
 - Servo
 - Stepper Motor
 - TM1638 LED Controller
-
-More drivers are coming soon...

drivers/gpio/gpio.go → drivers/gpio/gpio_driver.go

@@ -2,6 +2,9 @@ package gpio
 
 import (
 	"errors"
+	"sync"
+
+	"gobot.io/x/gobot/v2"
 )
 
 var (
@@ -61,3 +64,62 @@ type DigitalWriter interface {
 type DigitalReader interface {
 	DigitalRead(string) (val int, err error)
 }
+
+// Driver implements the interface gobot.Driver.
+type Driver struct {
+	name       string
+	connection gobot.Adaptor
+	afterStart func() error
+	beforeHalt func() error
+	gobot.Commander
+	mutex *sync.Mutex // mutex often needed to ensure that write-read sequences are not interrupted
+}
+
+// NewDriver creates a new generic and basic gpio gobot driver.
+func NewDriver(a gobot.Adaptor, name string) *Driver {
+	d := &Driver{
+		name:       gobot.DefaultName(name),
+		connection: a,
+		afterStart: func() error { return nil },
+		beforeHalt: func() error { return nil },
+		Commander:  gobot.NewCommander(),
+		mutex:      &sync.Mutex{},
+	}
+
+	return d
+}
+
+// Name returns the name of the gpio device.
+func (d *Driver) Name() string {
+	return d.name
+}
+
+// SetName sets the name of the gpio device.
+func (d *Driver) SetName(name string) {
+	d.name = name
+}
+
+// Connection returns the connection of the gpio device.
+func (d *Driver) Connection() gobot.Connection {
+	return d.connection.(gobot.Connection)
+}
+
+// Start initializes the gpio device.
+func (d *Driver) Start() error {
+	d.mutex.Lock()
+	defer d.mutex.Unlock()
+
+	// currently there is nothing to do here for the driver
+
+	return d.afterStart()
+}
+
+// Halt halts the gpio device.
+func (d *Driver) Halt() error {
+	d.mutex.Lock()
+	defer d.mutex.Unlock()
+
+	// currently there is nothing to do after halt for the driver
+
+	return d.beforeHalt()
+}

drivers/gpio/gpio_driver_test.go

@@ -0,0 +1,78 @@
+package gpio
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"gobot.io/x/gobot/v2"
+)
+
+var _ gobot.Driver = (*Driver)(nil)
+
+func initTestDriverWithStubbedAdaptor() (*Driver, *gpioTestAdaptor) {
+	a := newGpioTestAdaptor()
+	d := NewDriver(a, "GPIO_BASIC")
+	return d, a
+}
+
+func initTestDriver() *Driver {
+	d, _ := initTestDriverWithStubbedAdaptor()
+	return d
+}
+
+func TestNewDriver(t *testing.T) {
+	// arrange
+	a := newGpioTestAdaptor()
+	// act
+	var di interface{} = NewDriver(a, "GPIO_BASIC")
+	// assert
+	d, ok := di.(*Driver)
+	if !ok {
+		t.Errorf("NewDriver() should have returned a *Driver")
+	}
+	assert.Contains(t, d.name, "GPIO_BASIC")
+	assert.Equal(t, a, d.connection)
+	assert.NoError(t, d.afterStart())
+	assert.NoError(t, d.beforeHalt())
+	assert.NotNil(t, d.Commander)
+	assert.NotNil(t, d.mutex)
+}
+
+func TestSetName(t *testing.T) {
+	// arrange
+	d := initTestDriver()
+	// act
+	d.SetName("TESTME")
+	// assert
+	assert.Equal(t, "TESTME", d.Name())
+}
+
+func TestConnection(t *testing.T) {
+	// arrange
+	d, a := initTestDriverWithStubbedAdaptor()
+	// act, assert
+	assert.Equal(t, a, d.Connection())
+}
+
+func TestStart(t *testing.T) {
+	// arrange
+	d := initTestDriver()
+	// act, assert
+	assert.NoError(t, d.Start())
+	// arrange after start function
+	d.afterStart = func() error { return fmt.Errorf("after start error") }
+	// act, assert
+	assert.ErrorContains(t, d.Start(), "after start error")
+}
+
+func TestHalt(t *testing.T) {
+	// arrange
+	d := initTestDriver()
+	// act, assert
+	assert.NoError(t, d.Halt())
+	// arrange after start function
+	d.beforeHalt = func() error { return fmt.Errorf("before halt error") }
+	// act, assert
+	assert.ErrorContains(t, d.Halt(), "before halt error")
+}