sf0x.cpp

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/**
 * @file sf0x.cpp
 * @author Lorenz Meier <lm@inf.ethz.ch>
 * @author Greg Hulands
 *
 * Driver for the Lightware SF0x laser rangefinder series
 */

#include <px4_platform_common/px4_config.h>
#include <px4_platform_common/getopt.h>
#include <px4_platform_common/px4_work_queue/ScheduledWorkItem.hpp>

#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 <termios.h>

#include <perf/perf_counter.h>

#include <drivers/drv_hrt.h>
#include <drivers/drv_range_finder.h>
#include <drivers/device/device.h>
#include <drivers/device/ringbuffer.h>
#include <lib/parameters/param.h>

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

#include "sf0x_parser.h"

/* Configuration Constants */

#define SF0X_TAKE_RANGE_REG     'd'

// designated SERIAL4/5 on Pixhawk
#define SF0X_DEFAULT_PORT       "/dev/ttyS6"

class SF0X : public cdev::CDev, public px4::ScheduledWorkItem
{
public:
    SF0X(const char *port = SF0X_DEFAULT_PORT, uint8_t rotation = distance_sensor_s::ROTATION_DOWNWARD_FACING);
    virtual ~SF0X();

    virtual int             init() override;

    virtual ssize_t         read(device::file_t *filp, char *buffer, size_t buflen) override;
    virtual int         ioctl(device::file_t *filp, int cmd, unsigned long arg) override;

    /**
    * Diagnostics - print some basic information about the driver.
    */
    void                print_info();

private:
    char                _port[20];
    uint8_t _rotation;
    float               _min_distance;
    float               _max_distance;
    int                         _conversion_interval;
    ringbuffer::RingBuffer      *_reports;
    int             _measure_interval;
    bool                _collect_phase;
    int             _fd;
    char                _linebuf[10];
    unsigned            _linebuf_index;
    enum SF0X_PARSE_STATE       _parse_state;
    hrt_abstime         _last_read;

    int             _class_instance;
    int             _orb_class_instance;

    orb_advert_t            _distance_sensor_topic;

    unsigned            _consecutive_fail_count;

    perf_counter_t          _sample_perf;
    perf_counter_t          _comms_errors;

    /**
    * Initialise the automatic measurement state machine and start it.
    *
    * @note This function is called at open and error time.  It might make sense
    *       to make it more aggressive about resetting the bus in case of errors.
    */
    void                start();

    /**
    * Stop the automatic measurement state machine.
    */
    void                stop();

    /**
    * Set the min and max distance thresholds if you want the end points of the sensors
    * range to be brought in at all, otherwise it will use the defaults SF0X_MIN_DISTANCE
    * and SF0X_MAX_DISTANCE
    */
    void                set_minimum_distance(float min);
    void                set_maximum_distance(float max);
    float               get_minimum_distance();
    float               get_maximum_distance();

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

};

/*
 * Driver 'main' command.
 */
extern "C" __EXPORT int sf0x_main(int argc, char *argv[]);

SF0X::SF0X(const char *port, uint8_t rotation) :
    CDev(RANGE_FINDER0_DEVICE_PATH),
    ScheduledWorkItem(MODULE_NAME, px4::serial_port_to_wq(port)),
    _rotation(rotation),
    _min_distance(0.30f),
    _max_distance(40.0f),
    _conversion_interval(83334),
    _reports(nullptr),
    _measure_interval(0),
    _collect_phase(false),
    _fd(-1),
    _linebuf_index(0),
    _parse_state(SF0X_PARSE_STATE0_UNSYNC),
    _last_read(0),
    _class_instance(-1),
    _orb_class_instance(-1),
    _distance_sensor_topic(nullptr),
    _consecutive_fail_count(0),
    _sample_perf(perf_alloc(PC_ELAPSED, "sf0x_read")),
    _comms_errors(perf_alloc(PC_COUNT, "sf0x_com_err"))
{
    /* store port name */
    strncpy(_port, port, sizeof(_port) - 1);

    /* enforce null termination */
    _port[sizeof(_port) - 1] = '\0';

}

SF0X::~SF0X()
{
    /* make sure we are truly inactive */
    stop();

    /* free any existing reports */
    if (_reports != nullptr) {
        delete _reports;
    }

    if (_class_instance != -1) {
        unregister_class_devname(RANGE_FINDER_BASE_DEVICE_PATH, _class_instance);
    }

    perf_free(_sample_perf);
    perf_free(_comms_errors);
}

int
SF0X::init()
{
    int hw_model;
    param_get(param_find("SENS_EN_SF0X"), &hw_model);

    switch (hw_model) {

    case 1: /* SF02 (40m, 12 Hz)*/
        _min_distance = 0.3f;
        _max_distance = 40.0f;
        _conversion_interval =  83334;
        break;

    case 2:  /* SF10/a (25m 32Hz) */
        _min_distance = 0.01f;
        _max_distance = 25.0f;
        _conversion_interval = 31250;
        break;

    case 3:  /* SF10/b (50m 32Hz) */
        _min_distance = 0.01f;
        _max_distance = 50.0f;
        _conversion_interval = 31250;
        break;

    case 4:  /* SF10/c (100m 16Hz) */
        _min_distance = 0.01f;
        _max_distance = 100.0f;
        _conversion_interval = 62500;
        break;

    case 5:
        /* SF11/c (120m 20Hz) */
        _min_distance = 0.01f;
        _max_distance = 120.0f;
        _conversion_interval = 50000;
        break;

    default:
        PX4_ERR("invalid HW model %d.", hw_model);
        return -1;
    }

    /* status */
    int ret = 0;

    do { /* create a scope to handle exit conditions using break */

        /* do regular cdev init */
        ret = CDev::init();

        if (ret != OK) { break; }

        /* allocate basic report buffers */
        _reports = new ringbuffer::RingBuffer(2, sizeof(distance_sensor_s));

        if (_reports == nullptr) {
            PX4_ERR("alloc failed");
            ret = -1;
            break;
        }

        _class_instance = register_class_devname(RANGE_FINDER_BASE_DEVICE_PATH);

        /* get a publish handle on the range finder topic */
        struct distance_sensor_s ds_report = {};

        _distance_sensor_topic = orb_advertise_multi(ORB_ID(distance_sensor), &ds_report,
                     &_orb_class_instance, ORB_PRIO_HIGH);

        if (_distance_sensor_topic == nullptr) {
            PX4_ERR("failed to create distance_sensor object");
        }

    } while (0);

    return ret;
}

void
SF0X::set_minimum_distance(float min)
{
    _min_distance = min;
}

void
SF0X::set_maximum_distance(float max)
{
    _max_distance = max;
}

float
SF0X::get_minimum_distance()
{
    return _min_distance;
}

float
SF0X::get_maximum_distance()
{
    return _max_distance;
}

int
SF0X::ioctl(device::file_t *filp, int cmd, unsigned long arg)
{
    switch (cmd) {

    case SENSORIOCSPOLLRATE: {
            switch (arg) {

            /* zero would be bad */
            case 0:
                return -EINVAL;

            /* set default polling rate */
            case SENSOR_POLLRATE_DEFAULT: {
                    /* do we need to start internal polling? */
                    bool want_start = (_measure_interval == 0);

                    /* set interval for next measurement to minimum legal value */
                    _measure_interval = (_conversion_interval);

                    /* if we need to start the poll state machine, do it */
                    if (want_start) {
                        start();
                    }

                    return OK;
                }

            /* adjust to a legal polling interval in Hz */
            default: {

                    /* do we need to start internal polling? */
                    bool want_start = (_measure_interval == 0);

                    /* convert hz to tick interval via microseconds */
                    int interval = (1000000 / arg);

                    /* check against maximum rate */
                    if (interval < (_conversion_interval)) {
                        return -EINVAL;
                    }

                    /* update interval for next measurement */
                    _measure_interval = interval;

                    /* if we need to start the poll state machine, do it */
                    if (want_start) {
                        start();
                    }

                    return OK;
                }
            }
        }

    default:
        /* give it to the superclass */
        return CDev::ioctl(filp, cmd, arg);
    }
}

ssize_t
SF0X::read(device::file_t *filp, char *buffer, size_t buflen)
{
    unsigned count = buflen / sizeof(struct distance_sensor_s);
    struct distance_sensor_s *rbuf = reinterpret_cast<struct distance_sensor_s *>(buffer);
    int ret = 0;

    /* buffer must be large enough */
    if (count < 1) {
        return -ENOSPC;
    }

    /* if automatic measurement is enabled */
    if (_measure_interval > 0) {

        /*
         * While there is space in the caller's buffer, and reports, copy them.
         * Note that we may be pre-empted by the workq thread while we are doing this;
         * we are careful to avoid racing with them.
         */
        while (count--) {
            if (_reports->get(rbuf)) {
                ret += sizeof(*rbuf);
                rbuf++;
            }
        }

        /* if there was no data, warn the caller */
        return ret ? ret : -EAGAIN;
    }

    /* manual measurement - run one conversion */
    do {
        _reports->flush();

        /* trigger a measurement */
        if (OK != measure()) {
            ret = -EIO;
            break;
        }

        /* wait for it to complete */
        px4_usleep(_conversion_interval);

        /* run the collection phase */
        if (OK != collect()) {
            ret = -EIO;
            break;
        }

        /* state machine will have generated a report, copy it out */
        if (_reports->get(rbuf)) {
            ret = sizeof(*rbuf);
        }

    } while (0);

    return ret;
}

int
SF0X::measure()
{
    int ret;

    /*
     * Send the command to begin a measurement.
     */
    char cmd = SF0X_TAKE_RANGE_REG;
    ret = ::write(_fd, &cmd, 1);

    if (ret != sizeof(cmd)) {
        perf_count(_comms_errors);
        PX4_DEBUG("write fail %d", ret);
        return ret;
    }

    ret = OK;

    return ret;
}

int
SF0X::collect()
{
    perf_begin(_sample_perf);

    /* clear buffer if last read was too long ago */
    int64_t read_elapsed = hrt_elapsed_time(&_last_read);

    /* the buffer for read chars is buflen minus null termination */
    char readbuf[sizeof(_linebuf)];
    unsigned readlen = sizeof(readbuf) - 1;

    /* read from the sensor (uart buffer) */
    int ret = ::read(_fd, &readbuf[0], readlen);

    if (ret < 0) {
        PX4_DEBUG("read err: %d", ret);
        perf_count(_comms_errors);
        perf_end(_sample_perf);

        /* only throw an error if we time out */
        if (read_elapsed > (_conversion_interval * 2)) {
            return ret;

        } else {
            return -EAGAIN;
        }

    } else if (ret == 0) {
        return -EAGAIN;
    }

    _last_read = hrt_absolute_time();

    float distance_m = -1.0f;
    bool valid = false;

    for (int i = 0; i < ret; i++) {
        if (OK == sf0x_parser(readbuf[i], _linebuf, &_linebuf_index, &_parse_state, &distance_m)) {
            valid = true;
        }
    }

    if (!valid) {
        return -EAGAIN;
    }

    PX4_DEBUG("val (float): %8.4f, raw: %s, valid: %s", (double)distance_m, _linebuf, ((valid) ? "OK" : "NO"));

    struct distance_sensor_s report;

    report.timestamp = hrt_absolute_time();
    report.type = distance_sensor_s::MAV_DISTANCE_SENSOR_LASER;
    report.orientation = _rotation;
    report.current_distance = distance_m;
    report.min_distance = get_minimum_distance();
    report.max_distance = get_maximum_distance();
    report.variance = 0.0f;
    report.signal_quality = -1;
    /* TODO: set proper ID */
    report.id = 0;

    /* publish it */
    orb_publish(ORB_ID(distance_sensor), _distance_sensor_topic, &report);

    _reports->force(&report);

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

    ret = OK;

    perf_end(_sample_perf);
    return ret;
}

void
SF0X::start()
{
    /* reset the report ring and state machine */
    _collect_phase = false;
    _reports->flush();

    /* schedule a cycle to start things */
    ScheduleNow();
}

void
SF0X::stop()
{
    ScheduleClear();
}

void
SF0X::Run()
{
    /* fds initialized? */
    if (_fd < 0) {
        /* open fd */
        _fd = ::open(_port, O_RDWR | O_NOCTTY | O_NONBLOCK);

        if (_fd < 0) {
            PX4_ERR("open failed (%i)", errno);
            return;
        }

        struct termios uart_config;

        int termios_state;

        /* fill the struct for the new configuration */
        tcgetattr(_fd, &uart_config);

        /* clear ONLCR flag (which appends a CR for every LF) */
        uart_config.c_oflag &= ~ONLCR;

        /* no parity, one stop bit */
        uart_config.c_cflag &= ~(CSTOPB | PARENB);

        /* if distance sensor model is SF11/C, then set baudrate 115200, else 9600 */
        int hw_model;

        param_get(param_find("SENS_EN_SF0X"), &hw_model);

        unsigned speed;

        if (hw_model == 5) {
            speed = B115200;

        } else {
            speed = B9600;
        }

        /* set baud rate */
        if ((termios_state = cfsetispeed(&uart_config, speed)) < 0) {
            PX4_ERR("CFG: %d ISPD", termios_state);
        }

        if ((termios_state = cfsetospeed(&uart_config, speed)) < 0) {
            PX4_ERR("CFG: %d OSPD", termios_state);
        }

        if ((termios_state = tcsetattr(_fd, TCSANOW, &uart_config)) < 0) {
            PX4_ERR("baud %d ATTR", termios_state);
        }
    }

    /* collection phase? */
    if (_collect_phase) {

        /* perform collection */
        int collect_ret = collect();

        if (collect_ret == -EAGAIN) {
            /* reschedule to grab the missing bits, time to transmit 8 bytes @ 9600 bps */
            ScheduleDelayed(1042 * 8);

            return;
        }

        if (OK != collect_ret) {

            /* we know the sensor needs about four seconds to initialize */
            if (hrt_absolute_time() > 5 * 1000 * 1000LL && _consecutive_fail_count < 5) {
                PX4_ERR("collection error #%u", _consecutive_fail_count);
            }

            _consecutive_fail_count++;

            /* restart the measurement state machine */
            start();
            return;

        } else {
            /* apparently success */
            _consecutive_fail_count = 0;
        }

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

        /*
         * Is there a collect->measure gap?
         */
        if (_measure_interval > (_conversion_interval)) {

            /* schedule a fresh cycle call when we are ready to measure again */
            ScheduleDelayed(_measure_interval - _conversion_interval);

            return;
        }
    }

    /* measurement phase */
    if (OK != measure()) {
        PX4_DEBUG("measure error");
    }

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

    /* schedule a fresh cycle call when the measurement is done */
    ScheduleDelayed(_conversion_interval);
}

void
SF0X::print_info()
{
    perf_print_counter(_sample_perf);
    perf_print_counter(_comms_errors);
    printf("poll interval:  %d\n", _measure_interval);
    _reports->print_info("report queue");
}

/**
 * Local functions in support of the shell command.
 */
namespace sf0x
{

SF0X    *g_dev;

int start(const char *port, uint8_t rotation);
int stop();
int test();
int reset();
int info();

/**
 * Start the driver.
 */
int
start(const char *port, uint8_t rotation)
{
    int fd;

    if (g_dev != nullptr) {
        PX4_WARN("already started");
        return -1;
    }

    /* create the driver */
    g_dev = new SF0X(port, rotation);

    if (g_dev == nullptr) {
        goto fail;
    }

    if (OK != g_dev->init()) {
        goto fail;
    }

    /* set the poll rate to default, starts automatic data collection */
    fd = open(RANGE_FINDER0_DEVICE_PATH, 0);

    if (fd < 0) {
        PX4_ERR("device open fail (%i)", errno);
        goto fail;
    }

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

    return 0;

fail:

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

    return -1;
}

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

    } else {
        return -1;
    }

    return 0;
}

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

    int fd = open(RANGE_FINDER0_DEVICE_PATH, O_RDONLY);

    if (fd < 0) {
        PX4_ERR("%s open failed (try 'sf0x start' if the driver is not running", RANGE_FINDER0_DEVICE_PATH);
        return -1;
    }

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

    if (sz != sizeof(report)) {
        PX4_ERR("immediate read failed");
        return -1;
    }

    print_message(report);

    /* start the sensor polling at 2 Hz rate */
    if (OK != ioctl(fd, SENSORIOCSPOLLRATE, 2)) {
        PX4_ERR("failed to set 2Hz poll rate");
        return -1;
    }

    /* 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;
        int ret = poll(&fds, 1, 2000);

        if (ret != 1) {
            PX4_ERR("timed out");
            break;
        }

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

        if (sz != sizeof(report)) {
            PX4_ERR("read failed: got %zi vs exp. %zu", sz, sizeof(report));
            break;
        }

        print_message(report);
    }

    /* reset the sensor polling to the default rate */
    if (OK != ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT)) {
        PX4_ERR("ioctl SENSORIOCSPOLLRATE failed");
        return -1;
    }

    return 0;
}

/**
 * Reset the driver.
 */
int
reset()
{
    int fd = open(RANGE_FINDER0_DEVICE_PATH, O_RDONLY);

    if (fd < 0) {
        PX4_ERR("open failed (%i)", errno);
        return -1;
    }

    if (ioctl(fd, SENSORIOCRESET, 0) < 0) {
        PX4_ERR("driver reset failed");
        return -1;
    }

    if (ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT) < 0) {
        PX4_ERR("driver poll restart failed");
        return -1;
    }

    return 0;
}

/**
 * Print a little info about the driver.
 */
int
info()
{
    if (g_dev == nullptr) {
        PX4_ERR("driver not running");
        return -1;
    }

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

    return 0;
}

} // namespace

int
sf0x_main(int argc, char *argv[])
{
    uint8_t rotation = distance_sensor_s::ROTATION_DOWNWARD_FACING;
    const char *device_path = SF0X_DEFAULT_PORT;
    int ch;
    int myoptind = 1;
    const char *myoptarg = nullptr;

    while ((ch = px4_getopt(argc, argv, "R:d:", &myoptind, &myoptarg)) != EOF) {
        switch (ch) {
        case 'R':
            rotation = (uint8_t)atoi(myoptarg);
            break;

        case 'd':
            device_path = myoptarg;
            break;

        default:
            PX4_WARN("Unknown option!");
            return -1;
        }
    }

    if (myoptind >= argc) {
        goto out_error;
    }

    /*
     * Start/load the driver.
     */
    if (!strcmp(argv[myoptind], "start")) {
        return sf0x::start(device_path, rotation);
    }

    /*
     * Stop the driver
     */
    if (!strcmp(argv[myoptind], "stop")) {
        return sf0x::stop();
    }

    /*
     * Test the driver/device.
     */
    if (!strcmp(argv[myoptind], "test")) {
        return sf0x::test();
    }

    /*
     * Reset the driver.
     */
    if (!strcmp(argv[myoptind], "reset")) {
        return sf0x::reset();
    }

    /*
     * Print driver information.
     */
    if (!strcmp(argv[myoptind], "info") || !strcmp(argv[myoptind], "status")) {
        return sf0x::info();
    }

out_error:
    PX4_ERR("unrecognized command, try 'start', 'test', 'reset' or 'info'");
    return -1;
}