PX4-Autopilot/src/drivers/pca9685/pca9685.cpp

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/**
 * @file pca9685.cpp
 *
 * Driver for the PCA9685 I2C PWM module
 * The chip is used on the Adafruit I2C/PWM converter https://www.adafruit.com/product/815
 *
 * Parts of the code are adapted from the arduino library for the board
 * https://github.com/adafruit/Adafruit-PWM-Servo-Driver-Library
 * for the license of these parts see the
 * arduino_Adafruit_PWM_Servo_Driver_Library_license.txt file
 * see https://github.com/adafruit/Adafruit-PWM-Servo-Driver-Library for contributors
 *
 * @author Thomas Gubler <thomasgubler@gmail.com>
 */

#include <px4_config.h>

#include <drivers/device/i2c.h>

#include <sys/types.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <ctype.h>
#include <math.h>

#include <nuttx/wqueue.h>
#include <nuttx/clock.h>

#include <systemlib/perf_counter.h>
#include <systemlib/err.h>
#include <systemlib/systemlib.h>

#include <uORB/uORB.h>
#include <uORB/topics/actuator_controls.h>

#include <board_config.h>
#include <drivers/drv_io_expander.h>

#define PCA9685_SUBADR1 0x2
#define PCA9685_SUBADR2 0x3
#define PCA9685_SUBADR3 0x4

#define PCA9685_MODE1 0x0
#define PCA9685_PRESCALE 0xFE

#define LED0_ON_L 0x6
#define LED0_ON_H 0x7
#define LED0_OFF_L 0x8
#define LED0_OFF_H 0x9

#define ALLLED_ON_L 0xFA
#define ALLLED_ON_H 0xFB
#define ALLLED_OFF_L 0xFC
#define ALLLED_OF

#define ADDR 0x40	// I2C adress

#define PCA9685_DEVICE_PATH "/dev/pca9685"
#define PCA9685_BUS PX4_I2C_BUS_EXPANSION
#define PCA9685_PWMFREQ 60.0f
#define PCA9685_NCHANS 16 // total amount of pwm outputs

#define PCA9685_PWMMIN 150 // this is the 'minimum' pulse length count (out of 4096)
#define PCA9685_PWMMAX 600 // this is the 'maximum' pulse length count (out of 4096)_PWMFREQ 60.0f

#define PCA9685_PWMCENTER ((PCA9685_PWMMAX + PCA9685_PWMMIN)/2)
#define PCA9685_MAXSERVODEG 90.0f /* maximal servo deflection in degrees
				     PCA9685_PWMMIN <--> -PCA9685_MAXSERVODEG
				     PCA9685_PWMMAX <--> PCA9685_MAXSERVODEG
				     */
#define PCA9685_SCALE ((PCA9685_PWMMAX - PCA9685_PWMCENTER)/(M_DEG_TO_RAD_F * PCA9685_MAXSERVODEG)) // scales from rad to PWM

/* oddly, ERROR is not defined for c++ */
#ifdef ERROR
# undef ERROR
#endif
static const int ERROR = -1;

class PCA9685 : public device::I2C
{
public:
	PCA9685(int bus=PCA9685_BUS, uint8_t address=ADDR);
	virtual ~PCA9685();


	virtual int		init();
	virtual int		ioctl(struct file *filp, int cmd, unsigned long arg);
	virtual int		info();
	virtual int		reset();
	bool			is_running() { return _running; }

private:
	work_s			_work;


	enum IOX_MODE		_mode;
	bool			_running;
	int			_i2cpwm_interval;
	bool			_should_run;
	perf_counter_t		_comms_errors;

	uint8_t			_msg[6];

	int			_actuator_controls_sub;
	struct actuator_controls_s  _actuator_controls;
	uint16_t	    	_current_values[NUM_ACTUATOR_CONTROLS]; /**< stores the current pwm output
										  values as sent to the setPin() */

	bool _mode_on_initialized;  /** Set to true after the first call of i2cpwm in mode IOX_MODE_ON */

	static void		i2cpwm_trampoline(void *arg);
	void			i2cpwm();

	/**
	 * Helper function to set the pwm frequency
	 */
	int setPWMFreq(float freq);

	/**
	 * Helper function to set the demanded pwm value
	 * @param num pwm output number
	 */
	int setPWM(uint8_t num, uint16_t on, uint16_t off);

	/**
	 * Sets pin without having to deal with on/off tick placement and properly handles
	 * a zero value as completely off.  Optional invert parameter supports inverting
	 * the pulse for sinking to ground.
	 * @param num pwm output number
	 * @param val should be a value from 0 to 4095 inclusive.
	 */
	int setPin(uint8_t num, uint16_t val, bool invert = false);


	/* Wrapper to read a byte from addr */
	int read8(uint8_t addr, uint8_t &value);

	/* Wrapper to wite a byte to addr */
	int write8(uint8_t addr, uint8_t value);

};

/* for now, we only support one board */
namespace
{
PCA9685 *g_pca9685;
}

void pca9685_usage();

extern "C" __EXPORT int pca9685_main(int argc, char *argv[]);

PCA9685::PCA9685(int bus, uint8_t address) :
	I2C("pca9685", PCA9685_DEVICE_PATH, bus, address, 100000),
	_mode(IOX_MODE_OFF),
	_running(false),
	_i2cpwm_interval(SEC2TICK(1.0f/60.0f)),
	_should_run(false),
	_comms_errors(perf_alloc(PC_COUNT, "actuator_controls_2_comms_errors")),
	_actuator_controls_sub(-1),
	_actuator_controls(),
	_mode_on_initialized(false)
{
	memset(&_work, 0, sizeof(_work));
	memset(_msg, 0, sizeof(_msg));
	memset(_current_values, 0, sizeof(_current_values));
}

PCA9685::~PCA9685()
{
}

int
PCA9685::init()
{
	int ret;
	ret = I2C::init();
	if (ret != OK) {
		return ret;
	}

	ret = reset();
	if (ret != OK) {
		return ret;
	}

	ret = setPWMFreq(PCA9685_PWMFREQ);

	return ret;
}

int
PCA9685::ioctl(struct file *filp, int cmd, unsigned long arg)
{
	int ret = -EINVAL;
	switch (cmd) {

	case IOX_SET_MODE:

		if (_mode != (IOX_MODE)arg) {

			switch ((IOX_MODE)arg) {
			case IOX_MODE_OFF:
				warnx("shutting down");
				break;
			case IOX_MODE_ON:
				warnx("starting");
				break;
			case IOX_MODE_TEST_OUT:
				warnx("test starting");
				break;

			default:
				return -1;
			}

			_mode = (IOX_MODE)arg;
		}

		// if not active, kick it
		if (!_running) {
			_running = true;
			work_queue(LPWORK, &_work, (worker_t)&PCA9685::i2cpwm_trampoline, this, 1);
		}


		return OK;

	default:
		// see if the parent class can make any use of it
		ret = CDev::ioctl(filp, cmd, arg);
		break;
	}

	return ret;
}

int
PCA9685::info()
{
	int ret = OK;

	if (is_running()) {
		warnx("Driver is running, mode: %u", _mode);
	} else {
		warnx("Driver started but not running");
	}

	return ret;
}

void
PCA9685::i2cpwm_trampoline(void *arg)
{
	PCA9685 *i2cpwm = reinterpret_cast<PCA9685 *>(arg);

	i2cpwm->i2cpwm();
}

/**
 * Main loop function
 */
void
PCA9685::i2cpwm()
{
	if (_mode == IOX_MODE_TEST_OUT) {
		setPin(0, PCA9685_PWMCENTER);
		_should_run = true;
	} else if (_mode == IOX_MODE_OFF) {
		_should_run = false;
	} else {
		if (!_mode_on_initialized) {
			/* Subscribe to actuator control 2 (payload group for gimbal) */
			_actuator_controls_sub = orb_subscribe(ORB_ID(actuator_controls_2));
			/* set the uorb update interval lower than the driver pwm interval */
			orb_set_interval(_actuator_controls_sub, 1000.0f / PCA9685_PWMFREQ - 5);

			_mode_on_initialized = true;
		}

		/* Read the servo setpoints from the actuator control topics (gimbal) */
		bool updated;
		orb_check(_actuator_controls_sub, &updated);
		if (updated) {
			orb_copy(ORB_ID(actuator_controls_2), _actuator_controls_sub, &_actuator_controls);
			for (int i = 0; i < NUM_ACTUATOR_CONTROLS; i++) {
				/* Scale the controls to PWM, first multiply by pi to get rad,
				 * the control[i] values are on the range -1 ... 1 */
				uint16_t new_value = PCA9685_PWMCENTER +
					(_actuator_controls.control[i] * M_PI_F * PCA9685_SCALE);
				DEVICE_DEBUG("%d: current: %u, new %u, control %.2f", i, _current_values[i], new_value,
						(double)_actuator_controls.control[i]);
				if (new_value != _current_values[i] &&
						isfinite(new_value) &&
						new_value >= PCA9685_PWMMIN &&
						new_value <= PCA9685_PWMMAX) {
					/* This value was updated, send the command to adjust the PWM value */
					setPin(i, new_value);
					_current_values[i] = new_value;
				}
			}
		}
		_should_run = true;
	}

	// check if any activity remains, else stop
	if (!_should_run) {
		_running = false;
		return;
	}

	// re-queue ourselves to run again later
	_running = true;
	work_queue(LPWORK, &_work, (worker_t)&PCA9685::i2cpwm_trampoline, this, _i2cpwm_interval);
}

int
PCA9685::setPWM(uint8_t num, uint16_t on, uint16_t off)
{
	int ret;
	/* convert to correct message */
	_msg[0] = LED0_ON_L + 4 * num;
	_msg[1] = on;
	_msg[2] = on >> 8;
	_msg[3] = off;
	_msg[4] = off >> 8;

	/* try i2c transfer */
	ret = transfer(_msg, 5, nullptr, 0);

	if (OK != ret) {
		perf_count(_comms_errors);
		DEVICE_LOG("i2c::transfer returned %d", ret);
	}

	return ret;
}

int
PCA9685::setPin(uint8_t num, uint16_t val, bool invert)
{
	// Clamp value between 0 and 4095 inclusive.
	if (val > 4095) {
		val = 4095;
	}
	if (invert) {
		if (val == 0) {
			// Special value for signal fully on.
			return setPWM(num, 4096, 0);
		} else if (val == 4095) {
			// Special value for signal fully off.
			return setPWM(num, 0, 4096);
		} else {
			return setPWM(num, 0, 4095-val);
		}
	} else {
		if (val == 4095) {
			// Special value for signal fully on.
			return setPWM(num, 4096, 0);
		} else if (val == 0) {
			// Special value for signal fully off.
			return setPWM(num, 0, 4096);
		} else {
			return setPWM(num, 0, val);
		}
	}

	return ERROR;
}

int
PCA9685::setPWMFreq(float freq)
{
	int ret  = OK;
	freq *= 0.9f;  /* Correct for overshoot in the frequency setting (see issue
		https://github.com/adafruit/Adafruit-PWM-Servo-Driver-Library/issues/11). */
	float prescaleval = 25000000;
	prescaleval /= 4096;
	prescaleval /= freq;
	prescaleval -= 1;
	uint8_t prescale = uint8_t(prescaleval + 0.5f); //implicit floor()
	uint8_t oldmode;
	ret = read8(PCA9685_MODE1, oldmode);
	if (ret != OK) {
		return ret;
	}
	uint8_t newmode = (oldmode&0x7F) | 0x10; // sleep

	ret = write8(PCA9685_MODE1, newmode); // go to sleep
	if (ret != OK) {
		return ret;
	}
	ret = write8(PCA9685_PRESCALE, prescale); // set the prescaler
	if (ret != OK) {
		return ret;
	}
	ret = write8(PCA9685_MODE1, oldmode);
	if (ret != OK) {
		return ret;
	}

	usleep(5000); //5ms delay (from arduino driver)

	ret = write8(PCA9685_MODE1, oldmode | 0xa1);  //  This sets the MODE1 register to turn on auto increment.
	if (ret != OK) {
		return ret;
	}

	return ret;
}

/* Wrapper to read a byte from addr */
int
PCA9685::read8(uint8_t addr, uint8_t &value)
{
	int ret = OK;

	/* send addr */
	ret = transfer(&addr, sizeof(addr), nullptr, 0);
	if (ret != OK) {
		goto fail_read;
	}

	/* get value */
	ret = transfer(nullptr, 0, &value, 1);
	if (ret != OK) {
		goto fail_read;
	}

	return ret;

fail_read:
	perf_count(_comms_errors);
	DEVICE_LOG("i2c::transfer returned %d", ret);

	return ret;
}

int PCA9685::reset(void) {
	warnx("resetting");
	return write8(PCA9685_MODE1, 0x0);
}

/* Wrapper to wite a byte to addr */
int
PCA9685::write8(uint8_t addr, uint8_t value) {
	int ret = OK;
	_msg[0] = addr;
	_msg[1] = value;
	/* send addr and value */
	ret = transfer(_msg, 2, nullptr, 0);
	if (ret != OK) {
		perf_count(_comms_errors);
		DEVICE_LOG("i2c::transfer returned %d", ret);
	}
	return ret;
}

void
pca9685_usage()
{
	warnx("missing command: try 'start', 'test', 'stop', 'info'");
	warnx("options:");
	warnx("    -b i2cbus (%d)", PX4_I2C_BUS_EXPANSION);
	warnx("    -a addr (0x%x)", ADDR);
}

int
pca9685_main(int argc, char *argv[])
{
	int i2cdevice = -1;
	int i2caddr = ADDR; // 7bit

	int ch;

	// jump over start/off/etc and look at options first
	while ((ch = getopt(argc, argv, "a:b:")) != EOF) {
		switch (ch) {
		case 'a':
			i2caddr = strtol(optarg, NULL, 0);
			break;

		case 'b':
			i2cdevice = strtol(optarg, NULL, 0);
			break;

		default:
			pca9685_usage();
			exit(0);
		}
	}

	if (optind >= argc) {
		pca9685_usage();
		exit(1);
	}

	const char *verb = argv[optind];

	int fd;
	int ret;

	if (!strcmp(verb, "start")) {
		if (g_pca9685 != nullptr) {
			errx(1, "already started");
		}

		if (i2cdevice == -1) {
			// try the external bus first
			i2cdevice = PX4_I2C_BUS_EXPANSION;
			g_pca9685 = new PCA9685(PX4_I2C_BUS_EXPANSION, i2caddr);

			if (g_pca9685 != nullptr && OK != g_pca9685->init()) {
				delete g_pca9685;
				g_pca9685 = nullptr;
			}

			if (g_pca9685 == nullptr) {
				errx(1, "init failed");
			}
		}

		if (g_pca9685 == nullptr) {
			g_pca9685 = new PCA9685(i2cdevice, i2caddr);

			if (g_pca9685 == nullptr) {
				errx(1, "new failed");
			}

			if (OK != g_pca9685->init()) {
				delete g_pca9685;
				g_pca9685 = nullptr;
				errx(1, "init failed");
			}
		}
		fd = open(PCA9685_DEVICE_PATH, 0);
		if (fd == -1) {
			errx(1, "Unable to open " PCA9685_DEVICE_PATH);
		}
		ret = ioctl(fd, IOX_SET_MODE, (unsigned long)IOX_MODE_ON);
		close(fd);


		exit(0);
	}

	// need the driver past this point
	if (g_pca9685 == nullptr) {
		warnx("not started, run pca9685 start");
		exit(1);
	}

	if (!strcmp(verb, "info")) {
		g_pca9685->info();
		exit(0);
	}

	if (!strcmp(verb, "reset")) {
		g_pca9685->reset();
		exit(0);
	}


	if (!strcmp(verb, "test")) {
		fd = open(PCA9685_DEVICE_PATH, 0);

		if (fd == -1) {
			errx(1, "Unable to open " PCA9685_DEVICE_PATH);
		}

		ret = ioctl(fd, IOX_SET_MODE, (unsigned long)IOX_MODE_TEST_OUT);

		close(fd);
		exit(ret);
	}

	if (!strcmp(verb, "stop")) {
		fd = open(PCA9685_DEVICE_PATH, 0);

		if (fd == -1) {
			errx(1, "Unable to open " PCA9685_DEVICE_PATH);
		}

		ret = ioctl(fd, IOX_SET_MODE, (unsigned long)IOX_MODE_OFF);
		close(fd);

		// wait until we're not running any more
		for (unsigned i = 0; i < 15; i++) {
			if (!g_pca9685->is_running()) {
				break;
			}

			usleep(50000);
			printf(".");
			fflush(stdout);
		}
		printf("\n");
		fflush(stdout);

		if (!g_pca9685->is_running()) {
			delete g_pca9685;
			g_pca9685= nullptr;
			warnx("stopped, exiting");
			exit(0);
		} else {
			warnx("stop failed.");
			exit(1);
		}
	}

	pca9685_usage();
	exit(0);
}