i2c(PCA9685, adafruit): clean up architecture and fix init

.golangci.yml

@@ -88,7 +88,6 @@ linters:
     - exhaustruct # useful with some exclusions for existing code (e.g. mavlink/common/common.go)
     - funlen # useful with some tweeks (reduce bugs, simplify code, better understandable code)
     - gci # useful (improve readability)
-    - gochecknoinits # useful (reduce bugs, simplify bug catching)
     - gocognit # useful with some tweeks (better understandable code)
     - goconst # useful (reduce bugs)
     - gocritic # useful with some exclusions for existing code (e.g. mavlink/common/common.go)

README.md

@@ -309,8 +309,9 @@ 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
+  - Adafruit 1109 2x16 RGB-LCD with 5 keys
+  - Adafruit 2327 16-Channel PWM/Servo HAT Hat
+  - Adafruit 2348 DC and Stepper Motor Hat
   - ADS1015 Analog to Digital Converter
   - ADS1115 Analog to Digital Converter
   - ADXL345 Digital Accelerometer

drivers/i2c/README.md

@@ -12,8 +12,9 @@ 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 i2c devices are currently supported:
 
-- Adafruit 2x16 RGB-LCD with 5 keys
-- Adafruit Motor Hat
+- Adafruit 1109 2x16 RGB-LCD with 5 keys
+- Adafruit 2327 16-Channel PWM/Servo HAT Hat
+- Adafruit 2348 DC and Stepper Motor Hat
 - ADS1015 Analog to Digital Converter
 - ADS1115 Analog to Digital Converter
 - ADXL345 Digital Accelerometer

drivers/i2c/adafruit2327_driver.go

@@ -0,0 +1,45 @@
+package i2c
+
+import (
+	"gobot.io/x/gobot/v2"
+)
+
+// Adafruit2327Driver is a driver for Adafruit 16-Channel PWM/Servo HAT & Bonnet - a Raspberry Pi add-on, based on
+// PCA9685. This driver just wraps the PCA9685Driver.
+// Stacking 62 of them is possible (addresses 0x40..0x7E), for controlling up to 992 servos.
+// datasheet:
+// https://cdn-learn.adafruit.com/downloads/pdf/adafruit-16-channel-pwm-servo-hat-for-raspberry-pi.pdf
+type Adafruit2327Driver struct {
+	*PCA9685Driver
+}
+
+// NewAdafruit2327Driver initializes a new driver for PWM servos.
+// Params:
+//
+//	c Connector - the Adaptor to use with this Driver
+//
+// Optional params:
+//
+//	i2c.WithBus(int):	    bus to use with this driver
+//	i2c.WithAddress(int):	address to use with this driver
+func NewAdafruit2327Driver(c Connector, options ...func(Config)) *Adafruit2327Driver {
+	pca := NewPCA9685Driver(c, options...) // the default address of the driver is already 0x40
+	pca.SetName(gobot.DefaultName("Adafruit2327ServoHat"))
+	d := &Adafruit2327Driver{
+		PCA9685Driver: pca,
+	}
+
+	// TODO: add API funcs
+	return d
+}
+
+// SetServoMotorFreq sets the frequency for the currently addressed PWM Servo HAT.
+func (a *Adafruit2327Driver) SetServoMotorFreq(freq float64) error {
+	return a.SetPWMFreq(float32(freq))
+}
+
+// SetServoMotorPulse is a convenience function to specify the 'tick' value,
+// between 0-4095, when the signal will turn on, and when it will turn off.
+func (a *Adafruit2327Driver) SetServoMotorPulse(channel byte, on, off int32) error {
+	return a.SetPWM(int(channel), uint16(on), uint16(off))
+}

drivers/i2c/adafruit2327_driver_test.go

@@ -0,0 +1,94 @@
+package i2c
+
+import (
+	"errors"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"gobot.io/x/gobot/v2"
+)
+
+// this ensures that the implementation implements the gobot.Driver interface
+var _ gobot.Driver = (*Adafruit2327Driver)(nil)
+
+func initTestAdafruit2327WithStubbedAdaptor() (*Adafruit2327Driver, *i2cTestAdaptor) {
+	a := newI2cTestAdaptor()
+	d := NewAdafruit2327Driver(a)
+	if err := d.Start(); err != nil {
+		panic(err)
+	}
+	return d, a
+}
+
+func TestNewAdafruit2327Driver(t *testing.T) {
+	// arrange & act
+	d := NewAdafruit2327Driver(newI2cTestAdaptor())
+	// assert
+	assert.IsType(t, &Adafruit2327Driver{}, d)
+	assert.True(t, strings.HasPrefix(d.Name(), "Adafruit2327ServoHat"))
+	assert.Equal(t, 0x40, d.defaultAddress)
+}
+
+func TestAdafruit2327Options(t *testing.T) {
+	// This is a general test, that options are applied in constructor by using the common WithBus() option and
+	// least one of this driver. Further tests for options can also be done by call of "WithOption(val)(d)".
+	// arrange & act
+	d := NewAdafruit2327Driver(newI2cTestAdaptor(), WithBus(2))
+	// assert
+	assert.Equal(t, 2, d.GetBusOrDefault(1))
+}
+
+func TestAdafruit2327SetServoMotorFreq(t *testing.T) {
+	// arrange
+	d, a := initTestAdafruit2327WithStubbedAdaptor()
+	a.written = []byte{} // reset writes of former test
+	const freq = 60.0
+	// act
+	err := d.SetServoMotorFreq(freq)
+	// assert
+	assert.NoError(t, err)
+	assert.Equal(t, 9, len(a.written)) // detailed test, see "TestPCA9685SetPWMFreq"
+}
+
+func TestAdafruit2327SetServoMotorFreqError(t *testing.T) {
+	// arrange
+	d, a := initTestAdafruit2327WithStubbedAdaptor()
+	a.i2cWriteImpl = func([]byte) (int, error) {
+		return 0, errors.New("write error")
+	}
+	const freq = 60.0
+	// act & assert
+	assert.ErrorContains(t, d.SetServoMotorFreq(freq), "write error")
+}
+
+func TestAdafruit2327SetServoMotorPulse(t *testing.T) {
+	// arrange
+	d, a := initTestAdafruit2327WithStubbedAdaptor()
+	a.written = []byte{} // reset writes of former test
+	const (
+		channel byte  = 7
+		on      int32 = 1234
+		off     int32 = 4321
+	)
+	// act
+	err := d.SetServoMotorPulse(channel, on, off)
+	// assert
+	assert.NoError(t, err)
+	assert.Equal(t, 8, len(a.written)) // detailed test, see "TestPCA9685SetPWM"
+}
+
+func TestAdafruit2327SetServoMotorPulseError(t *testing.T) {
+	// arrange
+	d, a := initTestAdafruit2327WithStubbedAdaptor()
+	a.i2cWriteImpl = func([]byte) (int, error) {
+		return 0, errors.New("write error")
+	}
+	const (
+		channel byte  = 7
+		on      int32 = 1234
+		off     int32 = 4321
+	)
+	// act & assert
+	assert.ErrorContains(t, d.SetServoMotorPulse(channel, on, off), "write error")
+}