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package beaglebone
import (
"errors"
"fmt"
"os"
"path/filepath"
"strconv"
"strings"
"sync"
multierror "github.com/hashicorp/go-multierror"
"gobot.io/x/gobot"
"gobot.io/x/gobot/drivers/i2c"
"gobot.io/x/gobot/drivers/spi"
"gobot.io/x/gobot/sysfs"
)
type pwmPinData struct {
channel int
path string
}
const pwmDefaultPeriod = 500000
// Adaptor is the gobot.Adaptor representation for the Beaglebone Black/Green
type Adaptor struct {
name string
digitalPins []*sysfs.DigitalPin
pwmPins map[string]*sysfs.PWMPin
i2cBuses map[int]i2c.I2cDevice
usrLed string
analogPath string
pinMap map[string]int
pwmPinMap map[string]pwmPinData
analogPinMap map[string]string
mutex *sync.Mutex
findPin func(pinPath string) (string, error)
spiDefaultBus int
spiDefaultChip int
spiBuses [2]spi.Connection
spiDefaultMode int
spiDefaultMaxSpeed int64
}
// NewAdaptor returns a new Beaglebone Black/Green Adaptor
func NewAdaptor() *Adaptor {
b := &Adaptor{
name: gobot.DefaultName("BeagleboneBlack"),
digitalPins: make([]*sysfs.DigitalPin, 120),
pwmPins: make(map[string]*sysfs.PWMPin),
i2cBuses: make(map[int]i2c.I2cDevice),
mutex: &sync.Mutex{},
pinMap: bbbPinMap,
pwmPinMap: bbbPwmPinMap,
analogPinMap: bbbAnalogPinMap,
findPin: func(pinPath string) (string, error) {
files, err := filepath.Glob(pinPath)
return files[0], err
},
}
b.setPaths()
return b
}
func (b *Adaptor) setPaths() {
b.usrLed = "/sys/class/leds/beaglebone:green:"
b.analogPath = "/sys/bus/iio/devices/iio:device0"
b.spiDefaultBus = 0
b.spiDefaultMode = 0
b.spiDefaultMaxSpeed = 500000
}
// Name returns the Adaptor name
func (b *Adaptor) Name() string { return b.name }
// SetName sets the Adaptor name
func (b *Adaptor) SetName(n string) { b.name = n }
// Connect initializes the pwm and analog dts.
func (b *Adaptor) Connect() error {
return nil
}
// Finalize releases all i2c devices and exported analog, digital, pwm pins.
func (b *Adaptor) Finalize() (err error) {
b.mutex.Lock()
defer b.mutex.Unlock()
for _, pin := range b.digitalPins {
if pin != nil {
if e := pin.Unexport(); e != nil {
err = multierror.Append(err, e)
}
}
}
for _, pin := range b.pwmPins {
if pin != nil {
if e := pin.Unexport(); e != nil {
err = multierror.Append(err, e)
}
}
}
for _, bus := range b.i2cBuses {
if bus != nil {
if e := bus.Close(); e != nil {
err = multierror.Append(err, e)
}
}
}
for _, bus := range b.spiBuses {
if bus != nil {
if e := bus.Close(); e != nil {
err = multierror.Append(err, e)
}
}
}
return
}
// PwmWrite writes the 0-254 value to the specified pin
func (b *Adaptor) PwmWrite(pin string, val byte) (err error) {
pwmPin, err := b.PWMPin(pin)
if err != nil {
return
}
period, err := pwmPin.Period()
if err != nil {
return err
}
duty := gobot.FromScale(float64(val), 0, 255.0)
return pwmPin.SetDutyCycle(uint32(float64(period) * duty))
}
// ServoWrite writes a servo signal to the specified pin
func (b *Adaptor) ServoWrite(pin string, angle byte) (err error) {
pwmPin, err := b.PWMPin(pin)
if err != nil {
return
}
// TODO: take into account the actual period setting, not just assume default
const minDuty = 100 * 0.0005 * pwmDefaultPeriod
const maxDuty = 100 * 0.0020 * pwmDefaultPeriod
duty := uint32(gobot.ToScale(gobot.FromScale(float64(angle), 0, 180), minDuty, maxDuty))
return pwmPin.SetDutyCycle(duty)
}
// DigitalRead returns a digital value from specified pin
func (b *Adaptor) DigitalRead(pin string) (val int, err error) {
sysfsPin, err := b.DigitalPin(pin, sysfs.IN)
if err != nil {
return
}
return sysfsPin.Read()
}
// DigitalWrite writes a digital value to specified pin.
// valid usr pin values are usr0, usr1, usr2 and usr3
func (b *Adaptor) DigitalWrite(pin string, val byte) (err error) {
if strings.Contains(pin, "usr") {
fi, e := sysfs.OpenFile(b.usrLed+pin+"/brightness", os.O_WRONLY|os.O_APPEND, 0666)
defer fi.Close()
if e != nil {
return e
}
_, err = fi.WriteString(strconv.Itoa(int(val)))
return err
}
sysfsPin, err := b.DigitalPin(pin, sysfs.OUT)
if err != nil {
return err
}
return sysfsPin.Write(int(val))
}
// DigitalPin retrieves digital pin value by name
func (b *Adaptor) DigitalPin(pin string, dir string) (sysfsPin sysfs.DigitalPinner, err error) {
b.mutex.Lock()
defer b.mutex.Unlock()
i, err := b.translatePin(pin)
if err != nil {
return
}
if b.digitalPins[i] == nil {
b.digitalPins[i] = sysfs.NewDigitalPin(i)
if err = muxPin(pin, "gpio"); err != nil {
return
}
err := b.digitalPins[i].Export()
if err != nil {
return nil, err
}
}
if err = b.digitalPins[i].Direction(dir); err != nil {
return
}
return b.digitalPins[i], nil
}
// PWMPin returns matched pwmPin for specified pin number
func (b *Adaptor) PWMPin(pin string) (sysfsPin sysfs.PWMPinner, err error) {
b.mutex.Lock()
defer b.mutex.Unlock()
pinInfo, err := b.translatePwmPin(pin)
if err != nil {
return nil, err
}
if b.pwmPins[pin] == nil {
newPin := sysfs.NewPWMPin(pinInfo.channel)
if err = muxPin(pin, "pwm"); err != nil {
return
}
if newPin.Path, err = b.findPin(pinInfo.path); err != nil {
return
}
if err = newPin.Export(); err != nil {
return
}
if err = newPin.SetPeriod(pwmDefaultPeriod); err != nil {
return
}
if err = newPin.Enable(true); err != nil {
return
}
b.pwmPins[pin] = newPin
}
sysfsPin = b.pwmPins[pin]
return
}
// AnalogRead returns an analog value from specified pin
func (b *Adaptor) AnalogRead(pin string) (val int, err error) {
analogPin, err := b.translateAnalogPin(pin)
if err != nil {
return
}
fi, err := sysfs.OpenFile(fmt.Sprintf("%v/%v", b.analogPath, analogPin), os.O_RDONLY, 0644)
defer fi.Close()
if err != nil {
return
}
var buf = make([]byte, 1024)
_, err = fi.Read(buf)
if err != nil {
return
}
val, _ = strconv.Atoi(strings.Split(string(buf), "\n")[0])
return
}
// GetConnection returns a connection to a device on a specified bus.
// Valid bus number is either 0 or 2 which corresponds to /dev/i2c-0 or /dev/i2c-2.
func (b *Adaptor) GetConnection(address int, bus int) (connection i2c.Connection, err error) {
b.mutex.Lock()
defer b.mutex.Unlock()
if (bus != 0) && (bus != 2) {
return nil, fmt.Errorf("Bus number %d out of range", bus)
}
if b.i2cBuses[bus] == nil {
b.i2cBuses[bus], err = sysfs.NewI2cDevice(fmt.Sprintf("/dev/i2c-%d", bus))
}
return i2c.NewConnection(b.i2cBuses[bus], address), err
}
// GetDefaultBus returns the default i2c bus for this platform
func (b *Adaptor) GetDefaultBus() int {
return 2
}
// GetSpiConnection returns an spi connection to a device on a specified bus.
// Valid bus number is [0..1] which corresponds to /dev/spidev0.0 through /dev/spidev0.1.
func (b *Adaptor) GetSpiConnection(busNum, chipNum, mode, bits int, maxSpeed int64) (connection spi.Connection, err error) {
b.mutex.Lock()
defer b.mutex.Unlock()
if (busNum < 0) || (busNum > 1) {
return nil, fmt.Errorf("Bus number %d out of range", busNum)
}
if b.spiBuses[busNum] == nil {
b.spiBuses[busNum], err = spi.GetSpiConnection(busNum, chipNum, mode, bits, maxSpeed)
}
return b.spiBuses[busNum], err
}
// GetSpiDefaultBus returns the default spi bus for this platform.
func (b *Adaptor) GetSpiDefaultBus() int {
return b.spiDefaultBus
}
// GetSpiDefaultChip returns the default spi chip for this platform.
func (b *Adaptor) GetSpiDefaultChip() int {
return b.spiDefaultChip
}
// GetSpiDefaultMode returns the default spi mode for this platform.
func (b *Adaptor) GetSpiDefaultMode() int {
return b.spiDefaultMode
}
// GetSpiDefaultBits returns the default spi number of bits for this platform.
func (b *Adaptor) GetSpiDefaultBits() int {
return 8
}
// GetSpiDefaultMaxSpeed returns the default spi bus for this platform.
func (b *Adaptor) GetSpiDefaultMaxSpeed() int64 {
return b.spiDefaultMaxSpeed
}
// translatePin converts digital pin name to pin position
func (b *Adaptor) translatePin(pin string) (value int, err error) {
if val, ok := b.pinMap[pin]; ok {
value = val
} else {
err = errors.New("Not a valid pin")
}
return
}
func (b *Adaptor) translatePwmPin(pin string) (p pwmPinData, err error) {
if val, ok := b.pwmPinMap[pin]; ok {
p = val
} else {
err = errors.New("Not a valid PWM pin")
}
return
}
// translateAnalogPin converts analog pin name to pin position
func (b *Adaptor) translateAnalogPin(pin string) (value string, err error) {
if val, ok := b.analogPinMap[pin]; ok {
value = val
} else {
err = errors.New("Not a valid analog pin")
}
return
}
func muxPin(pin, cmd string) error {
path := fmt.Sprintf("/sys/devices/platform/ocp/ocp:%s_pinmux/state", pin)
fi, e := sysfs.OpenFile(path, os.O_WRONLY, 0666)
defer fi.Close()
if e != nil {
return e
}
_, e = fi.WriteString(cmd)
return e
}
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