345 lines
7.8 KiB
Go
345 lines
7.8 KiB
Go
package beaglebone
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import (
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"bufio"
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"errors"
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"fmt"
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"os"
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"os/exec"
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"path/filepath"
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"strconv"
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"strings"
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multierror "github.com/hashicorp/go-multierror"
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"gobot.io/x/gobot"
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"gobot.io/x/gobot/sysfs"
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)
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var glob = func(pattern string) (matches []string, err error) {
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return filepath.Glob(pattern)
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}
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// Adaptor is the gobot.Adaptor representation for the Beaglebone
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type Adaptor struct {
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name string
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kernel string
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digitalPins []sysfs.DigitalPin
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pwmPins map[string]*pwmPin
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i2cDevice sysfs.I2cDevice
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usrLed string
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ocp string
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analogPath string
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analogPinMap map[string]string
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slots string
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}
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// NewAdaptor returns a new Beaglebone Adaptor
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func NewAdaptor() *Adaptor {
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b := &Adaptor{
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name: gobot.DefaultName("Beaglebone"),
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digitalPins: make([]sysfs.DigitalPin, 120),
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pwmPins: make(map[string]*pwmPin),
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}
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b.setSlots()
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return b
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}
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func (b *Adaptor) setSlots() {
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ocp := "/sys/devices/ocp.*"
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slots := "/sys/devices/bone_capemgr.*"
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b.kernel = getKernel()
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if b.kernel[:1] == "4" {
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ocp = "/sys/devices/platform/ocp/ocp*"
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slots = "/sys/devices/platform/bone_capemgr"
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}
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b.usrLed = "/sys/class/leds/beaglebone:green:"
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g, _ := glob(ocp)
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b.ocp = g[0]
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g, _ = glob(slots)
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b.slots = fmt.Sprintf("%v/slots", g[0])
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}
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// Name returns the Adaptor name
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func (b *Adaptor) Name() string { return b.name }
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// SetName sets the Adaptor name
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func (b *Adaptor) SetName(n string) { b.name = n }
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// Kernel returns the Linux kernel version for the BeagleBone
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func (b *Adaptor) Kernel() string { return b.kernel }
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// Connect initializes the pwm and analog dts.
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func (b *Adaptor) Connect() error {
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// enable analog
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if b.kernel[:1] == "4" {
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if err := ensureSlot(b.slots, "BB-ADC"); err != nil {
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return err
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}
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b.analogPath = "/sys/bus/iio/devices/iio:device0"
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b.analogPinMap = analogPins44
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} else {
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if err := ensureSlot(b.slots, "cape-bone-iio"); err != nil {
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return err
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}
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g, err := glob(fmt.Sprintf("%v/helper.*", b.ocp))
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if err != nil {
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return err
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}
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b.analogPath = g[0]
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b.analogPinMap = analogPins3
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}
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// enable pwm
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if err := ensureSlot(b.slots, "am33xx_pwm"); err != nil {
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return err
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}
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return nil
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}
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// Finalize releases all i2c devices and exported analog, digital, pwm pins.
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func (b *Adaptor) Finalize() (err error) {
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for _, pin := range b.pwmPins {
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if pin != nil {
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if e := pin.release(); e != nil {
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err = multierror.Append(err, e)
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}
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}
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}
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for _, pin := range b.digitalPins {
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if pin != nil {
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if e := pin.Unexport(); e != nil {
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err = multierror.Append(err, e)
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}
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}
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}
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if b.i2cDevice != nil {
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if e := b.i2cDevice.Close(); e != nil {
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err = multierror.Append(err, e)
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}
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}
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return
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}
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// PwmWrite writes the 0-254 value to the specified pin
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func (b *Adaptor) PwmWrite(pin string, val byte) (err error) {
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return b.pwmWrite(pin, val)
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}
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// ServoWrite writes the 0-180 degree val to the specified pin.
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func (b *Adaptor) ServoWrite(pin string, val byte) (err error) {
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i, err := b.pwmPin(pin)
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if err != nil {
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return err
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}
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period := 16666666.0
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duty := (gobot.FromScale(float64(val), 0, 180.0) * 0.115) + 0.05
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return b.pwmPins[i].pwmWrite(strconv.Itoa(int(period)), strconv.Itoa(int(period*duty)))
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}
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// DigitalRead returns a digital value from specified pin
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func (b *Adaptor) DigitalRead(pin string) (val int, err error) {
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sysfsPin, err := b.digitalPin(pin, sysfs.IN)
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if err != nil {
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return
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}
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return sysfsPin.Read()
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}
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// DigitalWrite writes a digital value to specified pin.
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// valid usr pin values are usr0, usr1, usr2 and usr3
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func (b *Adaptor) DigitalWrite(pin string, val byte) (err error) {
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if strings.Contains(pin, "usr") {
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fi, err := sysfs.OpenFile(b.usrLed+pin+"/brightness", os.O_WRONLY|os.O_APPEND, 0666)
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defer fi.Close()
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if err != nil {
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return err
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}
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_, err = fi.WriteString(strconv.Itoa(int(val)))
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return err
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}
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sysfsPin, err := b.digitalPin(pin, sysfs.OUT)
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if err != nil {
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return err
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}
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return sysfsPin.Write(int(val))
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}
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// AnalogRead returns an analog value from specified pin
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func (b *Adaptor) AnalogRead(pin string) (val int, err error) {
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analogPin, err := b.translateAnalogPin(pin)
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if err != nil {
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return
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}
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fi, err := sysfs.OpenFile(fmt.Sprintf("%v/%v", b.analogPath, analogPin), os.O_RDONLY, 0644)
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defer fi.Close()
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if err != nil {
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return
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}
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var buf = make([]byte, 1024)
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_, err = fi.Read(buf)
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if err != nil {
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return
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}
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val, _ = strconv.Atoi(strings.Split(string(buf), "\n")[0])
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return
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}
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// I2cStart starts a i2c device in specified address on i2c bus /dev/i2c-1
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func (b *Adaptor) I2cStart(address int) (err error) {
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if b.i2cDevice == nil {
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b.i2cDevice, err = sysfs.NewI2cDevice("/dev/i2c-1", address)
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}
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return
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}
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// I2cWrite writes data to i2c device
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func (b *Adaptor) I2cWrite(address int, data []byte) (err error) {
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if err = b.i2cDevice.SetAddress(address); err != nil {
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return
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}
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_, err = b.i2cDevice.Write(data)
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return
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}
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// I2cRead returns size bytes from the i2c device
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func (b *Adaptor) I2cRead(address int, size int) (data []byte, err error) {
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if err = b.i2cDevice.SetAddress(address); err != nil {
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return
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}
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data = make([]byte, size)
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_, err = b.i2cDevice.Read(data)
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return
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}
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// translatePin converts digital pin name to pin position
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func (b *Adaptor) translatePin(pin string) (value int, err error) {
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for key, value := range pins {
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if key == pin {
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return value, nil
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}
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}
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err = errors.New("Not a valid pin")
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return
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}
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// translatePwmPin converts pwm pin name to pin position
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func (b *Adaptor) translatePwmPin(pin string) (value string, err error) {
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for key, value := range pwmPins {
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if key == pin {
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return value, nil
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}
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}
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err = errors.New("Not a valid pin")
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return
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}
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// translateAnalogPin converts analog pin name to pin position
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func (b *Adaptor) translateAnalogPin(pin string) (value string, err error) {
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for key, value := range b.analogPinMap {
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if key == pin {
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return value, nil
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}
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}
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err = errors.New("Not a valid pin")
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return
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}
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// digitalPin retrieves digital pin value by name
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func (b *Adaptor) digitalPin(pin string, dir string) (sysfsPin sysfs.DigitalPin, err error) {
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i, err := b.translatePin(pin)
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if err != nil {
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return
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}
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if b.digitalPins[i] == nil {
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b.digitalPins[i] = sysfs.NewDigitalPin(i)
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err := b.digitalPins[i].Export()
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if err != nil {
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return nil, err
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}
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}
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if err = b.digitalPins[i].Direction(dir); err != nil {
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return
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}
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return b.digitalPins[i], nil
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}
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// pwPin retrieves pwm pin value by name
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func (b *Adaptor) pwmPin(pin string) (i string, err error) {
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i, err = b.translatePwmPin(pin)
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if err != nil {
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return
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}
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if b.pwmPins[i] == nil {
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err = ensureSlot(b.slots, fmt.Sprintf("bone_pwm_%v", pin))
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if err != nil {
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return
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}
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b.pwmPins[i], err = newPwmPin(i, b.ocp)
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if err != nil {
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return
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}
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}
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return
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}
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// pwmWrite writes pwm value to specified pin
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func (b *Adaptor) pwmWrite(pin string, val byte) (err error) {
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i, err := b.pwmPin(pin)
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if err != nil {
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return
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}
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period := 500000.0
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duty := gobot.FromScale(float64(val), 0, 255.0)
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return b.pwmPins[i].pwmWrite(strconv.Itoa(int(period)), strconv.Itoa(int(period*duty)))
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}
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func ensureSlot(slots, item string) (err error) {
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fi, err := sysfs.OpenFile(slots, os.O_RDWR|os.O_APPEND, 0666)
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defer fi.Close()
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if err != nil {
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return
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}
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// ensure the slot is not already written into the capemanager
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// (from: https://github.com/mrmorphic/hwio/blob/master/module_bb_pwm.go#L190)
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scanner := bufio.NewScanner(fi)
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for scanner.Scan() {
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line := scanner.Text()
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if strings.Index(line, item) > 0 {
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return
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}
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}
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_, err = fi.WriteString(item)
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if err != nil {
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return err
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}
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fi.Sync()
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scanner = bufio.NewScanner(fi)
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for scanner.Scan() {
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line := scanner.Text()
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if strings.Index(line, item) > 0 {
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return
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}
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}
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return
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}
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func getKernel() string {
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result, _ := exec.Command("uname", "-r").Output()
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return strings.TrimSpace(string(result))
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}
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