firmware/src/platform/portduino/PiHal.h

#ifndef PI_HAL_H
#define PI_HAL_H

// include RadioLib
#include <RadioLib.h>

// include the library for Raspberry GPIO pins
#include "pigpio.h"

// create a new Raspberry Pi hardware abstraction layer
// using the pigpio library
// the HAL must inherit from the base RadioLibHal class
// and implement all of its virtual methods
class PiHal : public RadioLibHal
{
  public:
    // default constructor - initializes the base HAL and any needed private members
    PiHal(uint8_t spiChannel, uint32_t spiSpeed = 2000000)
        : RadioLibHal(PI_INPUT, PI_OUTPUT, PI_LOW, PI_HIGH, RISING_EDGE, FALLING_EDGE), _spiChannel(spiChannel),
          _spiSpeed(spiSpeed)
    {
    }

    void init() override
    {
        // first initialise pigpio library
        gpioInitialise();

        // now the SPI
        spiBegin();

        // Waveshare LoRaWAN Hat also needs pin 18 to be pulled high to enable the radio
        // gpioSetMode(18, PI_OUTPUT);
        // gpioWrite(18, PI_HIGH);
    }

    void term() override
    {
        // stop the SPI
        spiEnd();

        // pull the enable pin low
        // gpioSetMode(18, PI_OUTPUT);
        // gpioWrite(18, PI_LOW);

        // finally, stop the pigpio library
        gpioTerminate();
    }

    // GPIO-related methods (pinMode, digitalWrite etc.) should check
    // RADIOLIB_NC as an alias for non-connected pins
    void pinMode(uint32_t pin, uint32_t mode) override
    {
        if (pin == RADIOLIB_NC) {
            return;
        }

        gpioSetMode(pin, mode);
    }

    void digitalWrite(uint32_t pin, uint32_t value) override
    {
        if (pin == RADIOLIB_NC) {
            return;
        }

        gpioWrite(pin, value);
    }

    uint32_t digitalRead(uint32_t pin) override
    {
        if (pin == RADIOLIB_NC) {
            return (0);
        }

        return (gpioRead(pin));
    }

    void attachInterrupt(uint32_t interruptNum, void (*interruptCb)(void), uint32_t mode) override
    {
        if (interruptNum == RADIOLIB_NC) {
            return;
        }
        if (gpioRead(interruptNum) == 1) {
            interruptCb();
        } else {
            gpioSetAlertFunc(interruptNum, (gpioISRFunc_t)interruptCb);
        }
    }

    void detachInterrupt(uint32_t interruptNum) override
    {
        if (interruptNum == RADIOLIB_NC) {
            return;
        }

        gpioSetAlertFunc(interruptNum, NULL);
    }

    void delay(unsigned long ms) override { gpioDelay(ms * 1000); }

    void delayMicroseconds(unsigned long us) override { gpioDelay(us); }

    unsigned long millis() override { return (gpioTick() / 1000); }

    unsigned long micros() override { return (gpioTick()); }

    long pulseIn(uint32_t pin, uint32_t state, unsigned long timeout) override
    {
        if (pin == RADIOLIB_NC) {
            return (0);
        }

        this->pinMode(pin, PI_INPUT);
        uint32_t start = this->micros();
        uint32_t curtick = this->micros();

        while (this->digitalRead(pin) == state) {
            if ((this->micros() - curtick) > timeout) {
                return (0);
            }
        }

        return (this->micros() - start);
    }

    void spiBegin()
    {
        if (_spiHandle < 0) {
            _spiHandle = spiOpen(_spiChannel, _spiSpeed, 0);
        }
    }

    void spiBeginTransaction() {}

    void spiTransfer(uint8_t *out, size_t len, uint8_t *in) { spiXfer(_spiHandle, (char *)out, (char *)in, len); }

    void spiEndTransaction() {}

    void spiEnd()
    {
        if (_spiHandle >= 0) {
            spiClose(_spiHandle);
            _spiHandle = -1;
        }
    }

  private:
    // the HAL can contain any additional private members
    const unsigned int _spiSpeed;
    const uint8_t _spiChannel;
    int _spiHandle = -1;
};

#endif