hybridgroup.gobot/platforms/jetson/jetson_adaptor.go

package jetson

import (
	"errors"
	"fmt"
	"sync"

	multierror "github.com/hashicorp/go-multierror"
	"gobot.io/x/gobot/v2"
	"gobot.io/x/gobot/v2/platforms/adaptors"
	"gobot.io/x/gobot/v2/system"
)

const (
	pwmPeriodDefault = 3000000 // 3 ms = 333 Hz

	defaultI2cBusNumber = 1

	defaultSpiBusNumber  = 0
	defaultSpiChipNumber = 0
	defaultSpiMode       = 0
	defaultSpiBitsNumber = 8
	defaultSpiMaxSpeed   = 10000000
)

// Adaptor is the Gobot adaptor for the Jetson Nano
type Adaptor struct {
	name    string
	sys     *system.Accesser
	mutex   sync.Mutex
	pwmPins map[string]gobot.PWMPinner
	*adaptors.DigitalPinsAdaptor
	*adaptors.I2cBusAdaptor
	*adaptors.SpiBusAdaptor
}

// NewAdaptor creates a Jetson Nano adaptor
//
// Optional parameters:
//
//	adaptors.WithGpiodAccess():	use character device gpiod driver instead of sysfs
//	adaptors.WithSpiGpioAccess(sclk, nss, mosi, miso):	use GPIO's instead of /dev/spidev#.#
func NewAdaptor(opts ...func(adaptors.Optioner)) *Adaptor {
	sys := system.NewAccesser()
	c := &Adaptor{
		name: gobot.DefaultName("JetsonNano"),
		sys:  sys,
	}
	c.DigitalPinsAdaptor = adaptors.NewDigitalPinsAdaptor(sys, c.translateDigitalPin, opts...)
	c.I2cBusAdaptor = adaptors.NewI2cBusAdaptor(sys, c.validateI2cBusNumber, defaultI2cBusNumber)
	c.SpiBusAdaptor = adaptors.NewSpiBusAdaptor(sys, c.validateSpiBusNumber, defaultSpiBusNumber, defaultSpiChipNumber,
		defaultSpiMode, defaultSpiBitsNumber, defaultSpiMaxSpeed)
	return c
}

// Name returns the Adaptor's name
func (c *Adaptor) Name() string {
	c.mutex.Lock()
	defer c.mutex.Unlock()

	return c.name
}

// SetName sets the Adaptor's name
func (c *Adaptor) SetName(n string) {
	c.mutex.Lock()
	defer c.mutex.Unlock()

	c.name = n
}

// Connect create new connection to board and pins.
func (c *Adaptor) Connect() error {
	c.mutex.Lock()
	defer c.mutex.Unlock()

	if err := c.SpiBusAdaptor.Connect(); err != nil {
		return err
	}

	if err := c.I2cBusAdaptor.Connect(); err != nil {
		return err
	}

	c.pwmPins = make(map[string]gobot.PWMPinner)
	return c.DigitalPinsAdaptor.Connect()
}

// Finalize closes connection to board and pins
func (c *Adaptor) Finalize() error {
	c.mutex.Lock()
	defer c.mutex.Unlock()

	err := c.DigitalPinsAdaptor.Finalize()

	for _, pin := range c.pwmPins {
		if pin != nil {
			if perr := pin.Unexport(); err != nil {
				err = multierror.Append(err, perr)
			}
		}
	}
	c.pwmPins = nil

	if e := c.I2cBusAdaptor.Finalize(); e != nil {
		err = multierror.Append(err, e)
	}

	if e := c.SpiBusAdaptor.Finalize(); e != nil {
		err = multierror.Append(err, e)
	}
	return err
}

// PWMPin returns a Jetson Nano. PWMPin which provides the gobot.PWMPinner interface
func (c *Adaptor) PWMPin(pin string) (gobot.PWMPinner, error) {
	c.mutex.Lock()
	defer c.mutex.Unlock()

	return c.pwmPin(pin)
}

// PwmWrite writes a PWM signal to the specified pin
func (c *Adaptor) PwmWrite(pin string, val byte) (err error) {
	c.mutex.Lock()
	defer c.mutex.Unlock()

	sysPin, err := c.pwmPin(pin)
	if err != nil {
		return err
	}

	duty := uint32(gobot.FromScale(float64(val), 0, 255) * float64(pwmPeriodDefault))
	return sysPin.SetDutyCycle(duty)
}

// ServoWrite writes a servo signal to the specified pin
func (c *Adaptor) ServoWrite(pin string, angle byte) (err error) {
	c.mutex.Lock()
	defer c.mutex.Unlock()

	sysPin, err := c.pwmPin(pin)
	if err != nil {
		return err
	}

	duty := uint32(gobot.FromScale(float64(angle), 0, 180) * float64(pwmPeriodDefault))
	return sysPin.SetDutyCycle(duty)
}

func (c *Adaptor) pwmPin(pin string) (gobot.PWMPinner, error) {
	if c.pwmPins == nil {
		return nil, fmt.Errorf("not connected")
	}

	if c.pwmPins[pin] != nil {
		return c.pwmPins[pin], nil
	}

	fn, err := c.translatePwmPin(pin)
	if err != nil {
		return nil, err
	}

	c.pwmPins[pin] = NewPWMPin(c.sys, "/sys/class/pwm/pwmchip0", fn)
	if err := c.pwmPins[pin].Export(); err != nil {
		return nil, err
	}
	if err := c.pwmPins[pin].SetPeriod(pwmPeriodDefault); err != nil {
		return nil, err
	}
	if err := c.pwmPins[pin].SetEnabled(true); err != nil {
		return nil, err
	}

	return c.pwmPins[pin], nil
}

func (c *Adaptor) validateSpiBusNumber(busNr int) error {
	// Valid bus numbers are [0,1] which corresponds to /dev/spidev0.x through /dev/spidev1.x.
	// x is the chip number <255
	if (busNr < 0) || (busNr > 1) {
		return fmt.Errorf("Bus number %d out of range", busNr)
	}
	return nil
}

func (c *Adaptor) validateI2cBusNumber(busNr int) error {
	// Valid bus number is [0..1] which corresponds to /dev/i2c-0 through /dev/i2c-1.
	if (busNr < 0) || (busNr > 1) {
		return fmt.Errorf("Bus number %d out of range", busNr)
	}
	return nil
}

func (c *Adaptor) translateDigitalPin(id string) (string, int, error) {
	if line, ok := gpioPins[id]; ok {
		return "", line, nil
	}
	return "", -1, fmt.Errorf("'%s' is not a valid id for a digital pin", id)
}

func (c *Adaptor) translatePwmPin(pin string) (fn string, err error) {
	if fn, ok := pwmPins[pin]; ok {
		return fn, nil
	}
	return "", errors.New("Not a valid pin")
}