311 lines
7.2 KiB
Go
311 lines
7.2 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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"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/drivers/i2c"
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"gobot.io/x/gobot/sysfs"
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)
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const pwmDefaultPeriod = 500000
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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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digitalPins []*sysfs.DigitalPin
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pwmPins map[string]*sysfs.PWMPin
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i2cBuses map[int]sysfs.I2cDevice
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usrLed string
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analogPath 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]*sysfs.PWMPin),
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i2cBuses: make(map[int]sysfs.I2cDevice),
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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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b.slots = "/sys/devices/platform/bone_capemgr/slots"
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b.usrLed = "/sys/class/leds/beaglebone:green:"
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b.analogPath = "/sys/bus/iio/devices/iio:device0"
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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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// Connect initializes the pwm and analog dts.
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func (b *Adaptor) Connect() error {
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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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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.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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for _, pin := range b.pwmPins {
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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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for _, bus := range b.i2cBuses {
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if bus != nil {
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if e := bus.Close(); 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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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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pwmPin, 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, err := pwmPin.Period()
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if err != nil {
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return err
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}
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duty := gobot.FromScale(float64(val), 0, 255.0)
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return pwmPin.SetDutyCycle(uint32(float64(period) * duty))
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}
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// ServoWrite writes a servo signal to the specified pin
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func (b *Adaptor) ServoWrite(pin string, angle byte) (err error) {
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pwmPin, err := b.PWMPin(pin)
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if err != nil {
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return
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}
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// TODO: take into account the actual period setting, not just assume default
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const minDuty = 100 * 0.0005 * pwmDefaultPeriod
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const maxDuty = 100 * 0.0020 * pwmDefaultPeriod
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duty := uint32(gobot.ToScale(gobot.FromScale(float64(angle), 0, 180), minDuty, maxDuty))
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return pwmPin.SetDutyCycle(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, e := 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 e != nil {
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return e
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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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// DigitalPin retrieves digital pin value by name
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func (b *Adaptor) DigitalPin(pin string, dir string) (sysfsPin sysfs.DigitalPinner, 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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// PWMPin returns matched pwmPin for specified pin number
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func (b *Adaptor) PWMPin(pin string) (sysfsPin sysfs.PWMPinner, err error) {
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pinInfo, err := b.translatePwmPin(pin)
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if err != nil {
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return nil, err
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}
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if b.pwmPins[pin] == nil {
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newPin := sysfs.NewPWMPin(pinInfo.channel)
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newPin.Path = pinInfo.path
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if err = muxPWMPin(pin); err != nil {
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return
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}
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if err = newPin.Export(); err != nil {
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return
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}
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if err = newPin.SetPeriod(pwmDefaultPeriod); err != nil {
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return
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}
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// if err = newPin.InvertPolarity(false); err != nil {
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// return
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// }
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if err = newPin.Enable(true); err != nil {
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return
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}
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b.pwmPins[pin] = newPin
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}
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sysfsPin = b.pwmPins[pin]
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return
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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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// GetConnection returns a connection to a device on a specified bus.
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// Valid bus number is either 0 or 2 which corresponds to /dev/i2c-0 or /dev/i2c-2.
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func (b *Adaptor) GetConnection(address int, bus int) (connection i2c.Connection, err error) {
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if (bus != 0) && (bus != 2) {
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return nil, fmt.Errorf("Bus number %d out of range", bus)
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}
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if b.i2cBuses[bus] == nil {
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b.i2cBuses[bus], err = sysfs.NewI2cDevice(fmt.Sprintf("/dev/i2c-%d", bus))
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}
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return i2c.NewConnection(b.i2cBuses[bus], address), err
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}
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// GetDefaultBus returns the default i2c bus for this platform
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func (b *Adaptor) GetDefaultBus() int {
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return 2
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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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if val, ok := pins[pin]; ok {
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value = val
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} else {
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err = errors.New("Not a valid pin")
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}
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return
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}
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func (b *Adaptor) translatePwmPin(pin string) (p pwmPinData, err error) {
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if val, ok := pwmPins[pin]; ok {
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p = val
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} else {
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err = errors.New("Not a valid PWM pin")
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}
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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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if val, ok := analogPins[pin]; ok {
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value = val
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} else {
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err = errors.New("Not a valid analog pin")
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}
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return
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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 muxPWMPin(pin string) error {
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path := fmt.Sprintf("/sys/devices/platform/ocp/ocp:%s_pinmux/state", pin)
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fi, e := sysfs.OpenFile(path, os.O_WRONLY, 0666)
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defer fi.Close()
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if e != nil {
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return e
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}
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_, e = fi.WriteString("pwm")
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return e
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}
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