path: root/src/drivers/meas_airspeed/meas_airspeed.cpp

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/**
 * @file meas_airspeed.cpp
 * @author Lorenz Meier
 * @author Sarthak Kaingade
 * @author Simon Wilks
 * @author Thomas Gubler
 *
 * Driver for the MEAS Spec series connected via I2C.
 *
 * Supported sensors:
 *
 *    - MS4525DO (http://www.meas-spec.com/downloads/MS4525DO.pdf)
 *    - untested: MS5525DSO (http://www.meas-spec.com/downloads/MS5525DSO.pdf)
 *
 * Interface application notes:
 *
 *    - Interfacing to MEAS Digital Pressure Modules (http://www.meas-spec.com/downloads/Interfacing_to_MEAS_Digital_Pressure_Modules.pdf)
 */


#include <nuttx/config.h>

#include <drivers/device/i2c.h>

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

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

#include <board_config.h>

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

#include <drivers/drv_airspeed.h>
#include <drivers/drv_hrt.h>

#include <uORB/uORB.h>
#include <uORB/topics/differential_pressure.h>
#include <uORB/topics/subsystem_info.h>

#include <drivers/airspeed/airspeed.h>

/* I2C bus address is 1010001x */
#define I2C_ADDRESS_MS4525DO	0x28	//0x51 /* 7-bit address. */
#define PATH_MS4525		"/dev/ms4525"
/* The MS5525DSO address is 111011Cx, where C is the complementary value of the pin CSB */
#define I2C_ADDRESS_MS5525DSO	0x77	//0x77/* 7-bit address, addr. pin pulled low */
#define PATH_MS5525		"/dev/ms5525"

/* Register address */
#define ADDR_READ_MR			0x00	/* write to this address to start conversion */

/* Measurement rate is 100Hz */
#define CONVERSION_INTERVAL	(1000000 / 100)	/* microseconds */

class MEASAirspeed : public Airspeed
{
public:
	MEASAirspeed(int bus, int address = I2C_ADDRESS_MS4525DO, const char *path = PATH_MS4525);

protected:

	/**
	* Perform a poll cycle; collect from the previous measurement
	* and start a new one.
	*/
	virtual void	cycle();
	virtual int	measure();
	virtual int	collect();

};

/*
 * Driver 'main' command.
 */
extern "C" __EXPORT int meas_airspeed_main(int argc, char *argv[]);

MEASAirspeed::MEASAirspeed(int bus, int address, const char *path) : Airspeed(bus, address,
			CONVERSION_INTERVAL, path)
{

}

int
MEASAirspeed::measure()
{
	int ret;

	/*
	 * Send the command to begin a measurement.
	 */
	uint8_t cmd = 0;
	ret = transfer(&cmd, 1, nullptr, 0);

	if (OK != ret) {
		perf_count(_comms_errors);
	}

	return ret;
}

int
MEASAirspeed::collect()
{
	int	ret = -EIO;

	/* read from the sensor */
	uint8_t val[4] = {0, 0, 0, 0};


	perf_begin(_sample_perf);

	ret = transfer(nullptr, 0, &val[0], 4);

	if (ret < 0) {
		perf_count(_comms_errors);
		perf_end(_sample_perf);
		return ret;
	}

	uint8_t status = (val[0] & 0xC0) >> 6;

	switch (status) {
	case 0:
		break;

	case 1:
		/* fallthrough */
	case 2:
		/* fallthrough */
	case 3:
		perf_count(_comms_errors);
		perf_end(_sample_perf);
		return -EAGAIN;
	}

	int16_t dp_raw = 0, dT_raw = 0;
	dp_raw = (val[0] << 8) + val[1];
	/* mask the used bits */
	dp_raw = 0x3FFF & dp_raw;
	dT_raw = (val[2] << 8) + val[3];
	dT_raw = (0xFFE0 & dT_raw) >> 5;
	float temperature = ((200 * dT_raw) / 2047) - 50;

	/* calculate differential pressure. As its centered around 8000
	 * and can go positive or negative, enforce absolute value
	*/
	const float P_min = -1.0f;
	const float P_max = 1.0f;
	float diff_press_pa = fabsf((((float)dp_raw - 0.1f * 16383.0f) * (P_max - P_min) / (0.8f * 16383.0f) + P_min) * 6894.8f) - _diff_pres_offset;

	if (diff_press_pa < 0.0f) {
		diff_press_pa = 0.0f;
	}

	struct differential_pressure_s report;

	/* track maximum differential pressure measured (so we can work out top speed). */
	if (diff_press_pa > _max_differential_pressure_pa) {
		_max_differential_pressure_pa = diff_press_pa;
	}

	report.timestamp = hrt_absolute_time();
	report.error_count = perf_event_count(_comms_errors);
	report.temperature = temperature;
	report.differential_pressure_pa = diff_press_pa;
	report.voltage = 0;
	report.max_differential_pressure_pa = _max_differential_pressure_pa;

	if (_airspeed_pub > 0 && !(_pub_blocked)) {
		/* publish it */
		orb_publish(ORB_ID(differential_pressure), _airspeed_pub, &report);
	}

	new_report(report);

	/* notify anyone waiting for data */
	poll_notify(POLLIN);

	ret = OK;

	perf_end(_sample_perf);

	return ret;
}

void
MEASAirspeed::cycle()
{
	/* collection phase? */
	if (_collect_phase) {

		/* perform collection */
		if (OK != collect()) {
			/* restart the measurement state machine */
			start();
			return;
		}

		/* next phase is measurement */
		_collect_phase = false;

		/*
		 * Is there a collect->measure gap?
		 */
		if (_measure_ticks > USEC2TICK(CONVERSION_INTERVAL)) {

			/* schedule a fresh cycle call when we are ready to measure again */
			work_queue(HPWORK,
				   &_work,
				   (worker_t)&Airspeed::cycle_trampoline,
				   this,
				   _measure_ticks - USEC2TICK(CONVERSION_INTERVAL));

			return;
		}
	}

	/* measurement phase */
	if (OK != measure()) {
		log("measure error");
	}

	/* next phase is collection */
	_collect_phase = true;

	/* schedule a fresh cycle call when the measurement is done */
	work_queue(HPWORK,
		   &_work,
		   (worker_t)&Airspeed::cycle_trampoline,
		   this,
		   USEC2TICK(CONVERSION_INTERVAL));
}

/**
 * Local functions in support of the shell command.
 */
namespace meas_airspeed
{

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

MEASAirspeed	*g_dev = nullptr;

void	start(int i2c_bus);
void	stop();
void	test();
void	reset();
void	info();

/**
 * Start the driver.
 */
void
start(int i2c_bus)
{
	int fd;

	if (g_dev != nullptr) {
		errx(1, "already started");
	}

	/* create the driver, try the MS4525DO first */
	g_dev = new MEASAirspeed(i2c_bus, I2C_ADDRESS_MS4525DO, PATH_MS4525);

	/* check if the MS4525DO was instantiated */
	if (g_dev == nullptr) {
		goto fail;
	}

	/* try the MS5525DSO next if init fails */
	if (OK != g_dev->Airspeed::init()) {
		delete g_dev;
		g_dev = new MEASAirspeed(i2c_bus, I2C_ADDRESS_MS5525DSO, PATH_MS5525);

		/* check if the MS5525DSO was instantiated */
		if (g_dev == nullptr) {
			goto fail;
		}

		/* both versions failed if the init for the MS5525DSO fails, give up */
		if (OK != g_dev->Airspeed::init()) {
			goto fail;
		}
	}

	/* set the poll rate to default, starts automatic data collection */
	fd = open(AIRSPEED_DEVICE_PATH, O_RDONLY);

	if (fd < 0) {
		goto fail;
	}

	if (ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT) < 0) {
		goto fail;
	}

	exit(0);

fail:

	if (g_dev != nullptr) {
		delete g_dev;
		g_dev = nullptr;
	}

	errx(1, "driver start failed");
}

/**
 * Stop the driver
 */
void
stop()
{
	if (g_dev != nullptr) {
		delete g_dev;
		g_dev = nullptr;

	} else {
		errx(1, "driver not running");
	}

	exit(0);
}

/**
 * Perform some basic functional tests on the driver;
 * make sure we can collect data from the sensor in polled
 * and automatic modes.
 */
void
test()
{
	struct differential_pressure_s report;
	ssize_t sz;
	int ret;

	int fd = open(AIRSPEED_DEVICE_PATH, O_RDONLY);

	if (fd < 0) {
		err(1, "%s open failed (try 'meas_airspeed start' if the driver is not running", AIRSPEED_DEVICE_PATH);
	}

	/* do a simple demand read */
	sz = read(fd, &report, sizeof(report));

	if (sz != sizeof(report)) {
		err(1, "immediate read failed");
	}

	warnx("single read");
	warnx("diff pressure: %8.4f pa", (double)report.differential_pressure_pa);

	/* start the sensor polling at 2Hz */
	if (OK != ioctl(fd, SENSORIOCSPOLLRATE, 2)) {
		errx(1, "failed to set 2Hz poll rate");
	}

	/* read the sensor 5x and report each value */
	for (unsigned i = 0; i < 5; i++) {
		struct pollfd fds;

		/* wait for data to be ready */
		fds.fd = fd;
		fds.events = POLLIN;
		ret = poll(&fds, 1, 2000);

		if (ret != 1) {
			errx(1, "timed out waiting for sensor data");
		}

		/* now go get it */
		sz = read(fd, &report, sizeof(report));

		if (sz != sizeof(report)) {
			err(1, "periodic read failed");
		}

		warnx("periodic read %u", i);
		warnx("diff pressure: %8.4f pa", (double)report.differential_pressure_pa);
		warnx("temperature: %d C (0x%02x)", (int)report.temperature, (unsigned) report.temperature);
	}

	/* reset the sensor polling to its default rate */
	if (OK != ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT)) {
		errx(1, "failed to set default rate");
	}

	errx(0, "PASS");
}

/**
 * Reset the driver.
 */
void
reset()
{
	int fd = open(AIRSPEED_DEVICE_PATH, O_RDONLY);

	if (fd < 0) {
		err(1, "failed ");
	}

	if (ioctl(fd, SENSORIOCRESET, 0) < 0) {
		err(1, "driver reset failed");
	}

	if (ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT) < 0) {
		err(1, "driver poll restart failed");
	}

	exit(0);
}

/**
 * Print a little info about the driver.
 */
void
info()
{
	if (g_dev == nullptr) {
		errx(1, "driver not running");
	}

	printf("state @ %p\n", g_dev);
	g_dev->print_info();

	exit(0);
}

} // namespace


static void
meas_airspeed_usage()
{
	warnx("usage: meas_airspeed command [options]");
	warnx("options:");
	warnx("\t-b --bus i2cbus (%d)", PX4_I2C_BUS_DEFAULT);
	warnx("command:");
	warnx("\tstart|stop|reset|test|info");
}

int
meas_airspeed_main(int argc, char *argv[])
{
	int i2c_bus = PX4_I2C_BUS_DEFAULT;

	int i;

	for (i = 1; i < argc; i++) {
		if (strcmp(argv[i], "-b") == 0 || strcmp(argv[i], "--bus") == 0) {
			if (argc > i + 1) {
				i2c_bus = atoi(argv[i + 1]);
			}
		}
	}

	/*
	 * Start/load the driver.
	 */
	if (!strcmp(argv[1], "start")) {
		meas_airspeed::start(i2c_bus);
	}

	/*
	 * Stop the driver
	 */
	if (!strcmp(argv[1], "stop")) {
		meas_airspeed::stop();
	}

	/*
	 * Test the driver/device.
	 */
	if (!strcmp(argv[1], "test")) {
		meas_airspeed::test();
	}

	/*
	 * Reset the driver.
	 */
	if (!strcmp(argv[1], "reset")) {
		meas_airspeed::reset();
	}

	/*
	 * Print driver information.
	 */
	if (!strcmp(argv[1], "info") || !strcmp(argv[1], "status")) {
		meas_airspeed::info();
	}

	meas_airspeed_usage();
	exit(0);
}