introduce generic i2c.Driver with example for digispark

fix missing/wrong entries in README
stabilize test

Makefile

@@ -8,9 +8,9 @@ EXAMPLES := $(shell grep -L 'joystick' $$(grep -L 'gocv' $(ALL_EXAMPLES)))
 # opencv platform currently skipped to prevent install of preconditions
 including_except := $(shell go list ./... | grep -v platforms/opencv)
 
-# Run tests on nearly all directories
+# Run tests on nearly all directories without test cache
 test:
-	go test -v $(including_except)
+	go test -count=1 -v $(including_except)
 
 # Run tests with race detection
 test_race:

README.md

@@ -260,6 +260,7 @@ Support for devices that use Inter-Integrated Circuit (I2C) have a shared set of
 drivers provided using the `gobot/drivers/i2c` package:
 
 - [I2C](https://en.wikipedia.org/wiki/I%C2%B2C) <=> [Drivers](https://github.com/hybridgroup/gobot/tree/master/drivers/i2c)
+	- Adafruit 2x16 RGB-LCD with 5 keys
 	- Adafruit Motor Hat
 	- ADS1015 Analog to Digital Converter
 	- ADS1115 Analog to Digital Converter
@@ -271,6 +272,7 @@ drivers provided using the `gobot/drivers/i2c` package:
 	- BMP280 Barometric Pressure/Temperature/Altitude Sensor
 	- BMP388 Barometric Pressure/Temperature/Altitude Sensor
 	- DRV2605L Haptic Controller
+	- Generic driver for read and write values to/from register address
 	- Grove Digital Accelerometer
 	- GrovePi Expansion Board
 	- Grove RGB LCD
@@ -285,11 +287,13 @@ drivers provided using the `gobot/drivers/i2c` package:
 	- MPL115A2 Barometer
 	- MPU6050 Accelerometer/Gyroscope
 	- PCA9685 16-channel 12-bit PWM/Servo Driver
+	- PCF8591 8-bit 4xA/D & 1xD/A converter
 	- SHT2x Temperature/Humidity
 	- SHT3x-D Temperature/Humidity
 	- SSD1306 OLED Display Controller
 	- TSL2561 Digital Luminosity/Lux/Light Sensor
 	- Wii Nunchuck Controller
+	- YL-40 Brightness/Temperature sensor, Potentiometer, analog input, analog output Driver
 
 Support for devices that use Serial Peripheral Interface (SPI) have
 a shared set of drivers provided using the `gobot/drivers/spi` package:

drivers/i2c/README.md

@@ -24,6 +24,7 @@ Gobot has a extensible system for connecting to hardware devices. The following
 - BMP280 Barometric Pressure/Temperature/Altitude Sensor
 - BMP388 Barometric Pressure/Temperature/Altitude Sensor
 - DRV2605L Haptic Controller
+- Generic driver for read and write values to/from register address
 - Grove Digital Accelerometer
 - GrovePi Expansion Board
 - Grove RGB LCD
@@ -44,7 +45,7 @@ Gobot has a extensible system for connecting to hardware devices. The following
 - SSD1306 OLED Display Controller
 - TSL2561 Digital Luminosity/Lux/Light Sensor
 - Wii Nunchuck Controller
-- Y-40 Brightness/Temperature sensor, Potentiometer, analog input, analog output Driver
+- YL-40 Brightness/Temperature sensor, Potentiometer, analog input, analog output Driver
 
 More drivers are coming soon...
 

drivers/i2c/helpers_test.go

@@ -22,6 +22,8 @@ var blue = castColor("blue")
 
 type i2cTestAdaptor struct {
 	name          string
+	bus           int
+	address       int
 	written       []byte
 	mtx           sync.Mutex
 	i2cConnectErr bool
@@ -153,10 +155,12 @@ func (t *i2cTestAdaptor) WriteBlockData(reg uint8, b []byte) error {
 	return t.writeBytes(buf)
 }
 
-func (t *i2cTestAdaptor) GetConnection( /* address */ int /* bus */, int) (connection Connection, err error) {
+func (t *i2cTestAdaptor) GetConnection(address int, bus int) (connection Connection, err error) {
 	if t.i2cConnectErr {
 		return nil, errors.New("Invalid i2c connection")
 	}
+	t.bus = bus
+	t.address = address
 	return t, nil
 }
 

drivers/i2c/i2c_config_test.go

@@ -0,0 +1,81 @@
+package i2c
+
+import (
+	"testing"
+
+	"gobot.io/x/gobot/gobottest"
+)
+
+func TestNewConfig(t *testing.T) {
+	// arrange, act
+	ci := NewConfig()
+	// assert
+	c, ok := ci.(*i2cConfig)
+	if !ok {
+		t.Errorf("NewConfig() should have returned a *i2cConfig")
+	}
+	gobottest.Assert(t, c.bus, BusNotInitialized)
+	gobottest.Assert(t, c.address, AddressNotInitialized)
+}
+
+func TestWithBus(t *testing.T) {
+	// arrange
+	c := NewConfig()
+	// act
+	c.WithBus(0x23)
+	// assert
+	gobottest.Assert(t, c.(*i2cConfig).bus, 0x23)
+}
+
+func TestWithAddress(t *testing.T) {
+	// arrange
+	c := NewConfig()
+	// act
+	c.WithAddress(0x24)
+	// assert
+	gobottest.Assert(t, c.(*i2cConfig).address, 0x24)
+}
+
+func TestGetBusOrDefaultWithBusOption(t *testing.T) {
+	var tests = map[string]struct {
+		init int
+		bus  int
+		want int
+	}{
+		"not_initialized": {init: -1, bus: 0x25, want: 0x25},
+		"initialized":     {init: 0x26, bus: 0x27, want: 0x26},
+	}
+	for name, tc := range tests {
+		t.Run(name, func(t *testing.T) {
+			// arrange
+			c := NewConfig()
+			// act
+			WithBus(tc.init)(c)
+			got := c.GetBusOrDefault(tc.bus)
+			// assert
+			gobottest.Assert(t, got, tc.want)
+		})
+	}
+}
+
+func TestGetAddressOrDefaultWithAddressOption(t *testing.T) {
+	var tests = map[string]struct {
+		init    int
+		address int
+		want    int
+	}{
+		"not_initialized": {init: -1, address: 0x28, want: 0x28},
+		"initialized":     {init: 0x29, address: 0x2A, want: 0x29},
+	}
+	for name, tc := range tests {
+		t.Run(name, func(t *testing.T) {
+			// arrange
+			c := NewConfig()
+			// act
+			WithAddress(tc.init)(c)
+			got := c.GetAddressOrDefault(tc.address)
+			// assert
+			gobottest.Assert(t, got, tc.want)
+		})
+	}
+}

drivers/i2c/i2c_driver.go

@@ -0,0 +1,130 @@
+package i2c
+
+import (
+	"fmt"
+	"strconv"
+	"sync"
+
+	"gobot.io/x/gobot"
+)
+
+// Driver implements the interface gobot.Driver.
+type Driver struct {
+	name           string
+	defaultAddress int
+	connector      Connector
+	connection     Connection
+	afterStart     func() error
+	beforeHalt     func() error
+	Config
+	gobot.Commander
+	mutex *sync.Mutex // mutex often needed to ensure that write-read sequences are not interrupted
+}
+
+// NewDriver creates a new generic and basic i2c gobot driver.
+func NewDriver(c Connector, name string, address int, options ...func(Config)) *Driver {
+	d := &Driver{
+		name:           gobot.DefaultName(name),
+		defaultAddress: address,
+		connector:      c,
+		afterStart:     func() error { return nil },
+		beforeHalt:     func() error { return nil },
+		Config:         NewConfig(),
+		Commander:      gobot.NewCommander(),
+		mutex:          &sync.Mutex{},
+	}
+
+	for _, option := range options {
+		option(d)
+	}
+
+	return d
+}
+
+// Name returns the name of the i2c device.
+func (d *Driver) Name() string {
+	return d.name
+}
+
+// SetName sets the name of the i2c device.
+func (d *Driver) SetName(name string) {
+	d.name = name
+}
+
+// Connection returns the connection of the i2c device.
+func (d *Driver) Connection() gobot.Connection {
+	return d.connector.(gobot.Connection)
+}
+
+// Start initializes the i2c device.
+func (d *Driver) Start() error {
+	d.mutex.Lock()
+	defer d.mutex.Unlock()
+
+	var err error
+	bus := d.GetBusOrDefault(d.connector.GetDefaultBus())
+	address := d.GetAddressOrDefault(int(d.defaultAddress))
+
+	if d.connection, err = d.connector.GetConnection(address, bus); err != nil {
+		return err
+	}
+
+	return d.afterStart()
+}
+
+// Halt halts the i2c device.
+func (d *Driver) Halt() error {
+	d.mutex.Lock()
+	defer d.mutex.Unlock()
+
+	if err := d.beforeHalt(); err != nil {
+		return err
+	}
+
+	// currently there is nothing to do here for the driver
+	return nil
+}
+
+// Write implements a simple write mechanism to the given register of an i2c device.
+func (d *Driver) Write(pin string, val int) error {
+	d.mutex.Lock()
+	defer d.mutex.Unlock()
+
+	register, err := driverParseRegister(pin)
+	if err != nil {
+		return err
+	}
+
+	// TODO: create buffer from size
+	// currently only one byte value is supported
+	b := []byte{uint8(val)}
+	return d.connection.WriteBlockData(uint8(register), b)
+}
+
+// Read implements a simple read mechanism from the given register of an i2c device.
+func (d *Driver) Read(pin string) (int, error) {
+	d.mutex.Lock()
+	defer d.mutex.Unlock()
+
+	register, err := driverParseRegister(pin)
+	if err != nil {
+		return 0, err
+	}
+
+	// TODO: create buffer from size
+	// currently only one byte value is supported
+	b := []byte{0}
+	if err := d.connection.ReadBlockData(register, b); err != nil {
+		return 0, err
+	}
+
+	return int(b[0]), nil
+}
+
+func driverParseRegister(pin string) (uint8, error) {
+	register, err := strconv.ParseUint(pin, 10, 8)
+	if err != nil {
+		return 0, fmt.Errorf("Could not parse the register from given pin '%s'", pin)
+	}
+	return uint8(register), nil
+}

drivers/i2c/i2c_driver_test.go

@@ -0,0 +1,139 @@
+package i2c
+
+import (
+	"errors"
+	"strings"
+	"testing"
+
+	"gobot.io/x/gobot"
+	"gobot.io/x/gobot/gobottest"
+)
+
+var _ gobot.Driver = (*Driver)(nil)
+
+func initDriverWithStubbedAdaptor() (*Driver, *i2cTestAdaptor) {
+	a := newI2cTestAdaptor()
+	d := NewDriver(a, "I2C_BASIC", 0x15)
+	return d, a
+}
+
+func initTestDriver() *Driver {
+	d, _ := initDriverWithStubbedAdaptor()
+	return d
+}
+
+func TestNewDriver(t *testing.T) {
+	// arrange
+	a := newI2cTestAdaptor()
+	// act
+	var di interface{} = NewDriver(a, "I2C_BASIC", 0x15)
+	// assert
+	d, ok := di.(*Driver)
+	if !ok {
+		t.Errorf("NewDriver() should have returned a *Driver")
+	}
+	gobottest.Assert(t, strings.Contains(d.name, "I2C_BASIC"), true)
+	gobottest.Assert(t, d.defaultAddress, 0x15)
+	gobottest.Assert(t, d.connector, a)
+	gobottest.Assert(t, d.connection, nil)
+	gobottest.Assert(t, d.afterStart(), nil)
+	gobottest.Assert(t, d.beforeHalt(), nil)
+	gobottest.Refute(t, d.Config, nil)
+	gobottest.Refute(t, d.Commander, nil)
+	gobottest.Refute(t, d.mutex, nil)
+}
+
+func TestSetName(t *testing.T) {
+	// arrange
+	d := initTestDriver()
+	// act
+	d.SetName("TESTME")
+	// assert
+	gobottest.Assert(t, d.Name(), "TESTME")
+}
+
+func TestConnection(t *testing.T) {
+	// arrange
+	d := initTestDriver()
+	// act, assert
+	gobottest.Refute(t, d.Connection(), nil)
+}
+
+func TestStart(t *testing.T) {
+	// arrange
+	d, a := initDriverWithStubbedAdaptor()
+	// act, assert
+	gobottest.Assert(t, d.Start(), nil)
+	gobottest.Assert(t, 0x15, a.address)
+}
+
+func TestStartConnectError(t *testing.T) {
+	// arrange
+	d, a := initDriverWithStubbedAdaptor()
+	a.Testi2cConnectErr(true)
+	// act, assert
+	gobottest.Assert(t, d.Start(), errors.New("Invalid i2c connection"))
+}
+
+func TestHalt(t *testing.T) {
+	// arrange
+	d := initTestDriver()
+	// act, assert
+	gobottest.Assert(t, d.Halt(), nil)
+}
+
+func TestWrite(t *testing.T) {
+	// arrange
+	const (
+		address     = "82"
+		wantAddress = uint8(0x52)
+		value       = 0x25
+	)
+	d, a := initDriverWithStubbedAdaptor()
+	d.Start()
+	// prepare all writes
+	numCallsWrite := 0
+	a.i2cWriteImpl = func([]byte) (int, error) {
+		numCallsWrite++
+		return 0, nil
+	}
+	// act
+	err := d.Write(address, value)
+	// assert
+	gobottest.Assert(t, err, nil)
+	gobottest.Assert(t, numCallsWrite, 1)
+	gobottest.Assert(t, a.written[0], wantAddress)
+	gobottest.Assert(t, a.written[1], uint8(value))
+}
+
+func TestRead(t *testing.T) {
+	// arrange
+	const (
+		address     = "83"
+		wantAddress = uint8(0x53)
+		want        = uint8(0x44)
+	)
+	d, a := initDriverWithStubbedAdaptor()
+	d.Start()
+	// prepare all writes
+	numCallsWrite := 0
+	a.i2cWriteImpl = func(b []byte) (int, error) {
+		numCallsWrite++
+		return 0, nil
+	}
+	// prepare all reads
+	numCallsRead := 0
+	a.i2cReadImpl = func(b []byte) (int, error) {
+		numCallsRead++
+		b[0] = want
+		return len(b), nil
+	}
+	// act
+	val, err := d.Read(address)
+	// assert
+	gobottest.Assert(t, err, nil)
+	gobottest.Assert(t, val, int(want))
+	gobottest.Assert(t, numCallsWrite, 1)
+	gobottest.Assert(t, a.written[0], wantAddress)
+	gobottest.Assert(t, numCallsRead, 1)
+}

examples/digispark_driver.go

@@ -0,0 +1,77 @@
+// +build example
+//
+// Do not build by default.
+
+package main
+
+import (
+	"fmt"
+	"strconv"
+	"time"
+
+	"gobot.io/x/gobot"
+	"gobot.io/x/gobot/drivers/i2c"
+	"gobot.io/x/gobot/platforms/digispark"
+)
+
+// This is an example for using the generic I2C driver to write and read values
+// to an i2c device. It is suitable for simple devices, e.g. EEPROM.
+// The example was tested with the EEPROM part of PCA9501.
+//
+// Procedure:
+// * write value to register (EEPROM address)
+// * read value back from register (EEPROM address) and check for differences
+func main() {
+	const (
+		defaultAddress = 0x7F
+		myAddress      = 0x44 // needs to be adjusted for your configuration
+	)
+	board := digispark.NewAdaptor()
+	drv := i2c.NewDriver(board, "PCA9501-EEPROM", defaultAddress, i2c.WithAddress(myAddress))
+	var eepromAddr uint8 = 0x00
+	var register string
+	var valWr uint8 = 0xFF
+	var valRd int
+	var err error
+
+	work := func() {
+		gobot.Every(50*time.Millisecond, func() {
+			// write a value 0-255 to EEPROM address 255-0
+			eepromAddr--
+			valWr++
+			register = strconv.Itoa(int(eepromAddr))
+			err = drv.Write(register, int(valWr))
+			if err != nil {
+				fmt.Println("err write:", err)
+			}
+
+			// write process needs some time, so wait at least 5ms before read a value
+			// when decreasing to much, the check below will fail
+			time.Sleep(5 * time.Millisecond)
+
+			// read value back and check for unexpected differences
+			valRd, err = drv.Read(register)
+			if err != nil {
+				fmt.Println("err read:", err)
+			}
+			if int(valWr) != valRd {
+				fmt.Printf("addr: %d wr: %d differ rd: %d\n", eepromAddr, valWr, valRd)
+			}
+
+			if eepromAddr%10 == 0 {
+				fmt.Printf("addr: %d, wr: %d rd: %d\n", eepromAddr, valWr, valRd)
+			}
+		})
+	}
+
+	robot := gobot.NewRobot("simpleDriverI2c",
+		[]gobot.Connection{board},
+		[]gobot.Device{drv},
+		work,
+	)
+
+	err = robot.Start()
+	if err != nil {
+		fmt.Println(err)
+	}
+}

robot_work_test.go

@@ -60,17 +60,18 @@ func TestRobotWorkRegistry(t *testing.T) {
 func TestRobotAutomationFunctions(t *testing.T) {
 	t.Run("Every with cancel", func(t *testing.T) {
 		robot := NewRobot("testbot")
+		counter := 0
 
-		rw := robot.Every(context.Background(), time.Millisecond*10, func() {
-			_ = 1 + 1 // perform mindless computation!
+		rw := robot.Every(context.Background(), time.Millisecond*100, func() {
+			counter++
 		})
 
-		time.Sleep(time.Millisecond * 25)
+		time.Sleep(time.Millisecond * 225)
 		rw.CallCancelFunc()
 
 		robot.WorkEveryWaitGroup.Wait()
 
-		assert.Equal(t, 2, rw.tickCount)
+		assert.Equal(t, 2, counter)
 		postDeleteKeys := collectStringKeysFromWorkRegistry(robot.workRegistry)
 		assert.NotContains(t, postDeleteKeys, rw.id.String())
 	})