lps25h.cpp

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 * modification, are permitted provided that the following conditions
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 *
 * 1. Redistributions of source code must retain the above copyright
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 *    used to endorse or promote products derived from this software
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/**
 * @file lps25h.cpp
 *
 * Driver for the LPS25H barometer connected via I2C or SPI.
 */

#include "lps25h.h"

/*
 * LPS25H internal constants and data structures.
 */

/* Max measurement rate is 25Hz */
#define LPS25H_CONVERSION_INTERVAL  (1000000 / 25)  /* microseconds */

#define ADDR_REF_P_XL       0x08
#define ADDR_REF_P_L        0x09
#define ADDR_REF_P_H        0x0A
#define ADDR_WHO_AM_I       0x0F
#define ADDR_RES_CONF       0x10
#define ADDR_CTRL_REG1      0x20
#define ADDR_CTRL_REG2      0x21
#define ADDR_CTRL_REG3      0x22
#define ADDR_CTRL_REG4      0x23
#define ADDR_INT_CFG        0x24
#define ADDR_INT_SOURCE     0x25

#define ADDR_STATUS_REG     0x27
#define ADDR_P_OUT_XL       0x28
#define ADDR_P_OUT_L        0x29
#define ADDR_P_OUT_H        0x2A
#define ADDR_TEMP_OUT_L     0x2B
#define ADDR_TEMP_OUT_H     0x2C

#define ADDR_FIFO_CTRL      0x2E
#define ADDR_FIFO_STATUS    0x2F
#define ADDR_THS_P_L        0x30
#define ADDR_THS_P_H        0x31

#define ADDR_RPDS_L     0x39
#define ADDR_RPDS_H     0x3A

/* Data sheet is ambigious if AVGT or AVGP is first */
#define RES_CONF_AVGT_8     0x00
#define RES_CONF_AVGT_32    0x01
#define RES_CONF_AVGT_128   0x02
#define RES_CONF_AVGT_512   0x03
#define RES_CONF_AVGP_8     0x00
#define RES_CONF_AVGP_32    0x04
#define RES_CONF_AVGP_128   0x08
#define RES_CONF_AVGP_512   0x0C

#define CTRL_REG1_SIM       (1 << 0)
#define CTRL_REG1_RESET_AZ  (1 << 1)
#define CTRL_REG1_BDU       (1 << 2)
#define CTRL_REG1_DIFF_EN   (1 << 3)
#define CTRL_REG1_PD        (1 << 7)
#define CTRL_REG1_ODR_SINGLE    (0 << 4)
#define CTRL_REG1_ODR_1HZ   (1 << 4)
#define CTRL_REG1_ODR_7HZ   (2 << 4)
#define CTRL_REG1_ODR_12HZ5 (3 << 4)
#define CTRL_REG1_ODR_25HZ  (4 << 4)

#define CTRL_REG2_ONE_SHOT  (1 << 0)
#define CTRL_REG2_AUTO_ZERO (1 << 1)
#define CTRL_REG2_SWRESET   (1 << 2)
#define CTRL_REG2_FIFO_MEAN_DEC (1 << 4)
#define CTRL_REG2_WTM_EN    (1 << 5)
#define CTRL_REG2_FIFO_EN   (1 << 6)
#define CTRL_REG2_BOOT      (1 << 7)

#define CTRL_REG3_INT1_S_DATA   0x0
#define CTRL_REG3_INT1_S_P_HIGH 0x1
#define CTRL_REG3_INT1_S_P_LOW  0x2
#define CTRL_REG3_INT1_S_P_LIM  0x3
#define CTRL_REG3_PP_OD     (1 << 6)
#define CTRL_REG3_INT_H_L   (1 << 7)

#define CTRL_REG4_P1_DRDY   (1 << 0)
#define CTRL_REG4_P1_OVERRUN    (1 << 1)
#define CTRL_REG4_P1_WTM    (1 << 2)
#define CTRL_REG4_P1_EMPTY  (1 << 3)

#define INTERRUPT_CFG_PH_E  (1 << 0)
#define INTERRUPT_CFG_PL_E  (1 << 1)
#define INTERRUPT_CFG_LIR   (1 << 2)

#define INT_SOURCE_PH       (1 << 0)
#define INT_SOURCE_PL       (1 << 1)
#define INT_SOURCE_IA       (1 << 2)

#define STATUS_REG_T_DA     (1 << 0)
#define STATUS_REG_P_DA     (1 << 1)
#define STATUS_REG_T_OR     (1 << 4)
#define STATUS_REG_P_OR     (1 << 5)

#define FIFO_CTRL_WTM_FMEAN_2   0x01
#define FIFO_CTRL_WTM_FMEAN_4   0x03
#define FIFO_CTRL_WTM_FMEAN_8   0x07
#define FIFO_CTRL_WTM_FMEAN_16  0x0F
#define FIFO_CTRL_WTM_FMEAN_32  0x1F
#define FIFO_CTRL_F_MODE_BYPASS (0x0 << 5)
#define FIFO_CTRL_F_MODE_FIFO   (0x1 << 5)
#define FIFO_CTRL_F_MODE_STREAM (0x2 << 5)
#define FIFO_CTRL_F_MODE_SFIFO  (0x3 << 5)
#define FIFO_CTRL_F_MODE_BSTRM  (0x4 << 5)
#define FIFO_CTRL_F_MODE_FMEAN  (0x6 << 5)
#define FIFO_CTRL_F_MODE_BFIFO  (0x7 << 5)

#define FIFO_STATUS_EMPTY   (1 << 5)
#define FIFO_STATUS_FULL    (1 << 6)
#define FIFO_STATUS_WTM     (1 << 7)

enum LPS25H_BUS {
    LPS25H_BUS_ALL = 0,
    LPS25H_BUS_I2C_INTERNAL,
    LPS25H_BUS_I2C_EXTERNAL,
    LPS25H_BUS_SPI
};

class LPS25H : public cdev::CDev, public px4::ScheduledWorkItem
{
public:
    LPS25H(device::Device *interface, const char *path);
    virtual ~LPS25H();

    virtual int     init();

    virtual ssize_t     read(struct file *filp, char *buffer, size_t buflen);
    virtual int     ioctl(struct file *filp, int cmd, unsigned long arg);

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

protected:
    device::Device          *_interface;

private:
    unsigned        _measure_interval{0};

    ringbuffer::RingBuffer  *_reports{nullptr};
    bool            _collect_phase{false};

    orb_advert_t        _baro_topic{nullptr};
    int         _orb_class_instance{-1};
    int         _class_instance{-1};

    perf_counter_t      _sample_perf;
    perf_counter_t      _comms_errors;

    sensor_baro_s   _last_report{};           /**< used for info() */

    /**
     * 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();

    /**
     * Reset the device
     */
    int         reset();

    /**
     * Perform a poll cycle; collect from the previous measurement
     * and start a new one.
     *
     * This is the heart of the measurement state machine.  This function
     * alternately starts a measurement, or collects the data from the
     * previous measurement.
     *
     * When the interval between measurements is greater than the minimum
     * measurement interval, a gap is inserted between collection
     * and measurement to provide the most recent measurement possible
     * at the next interval.
     */
    void            Run() override;

    /**
     * Write a register.
     *
     * @param reg       The register to write.
     * @param val       The value to write.
     * @return      OK on write success.
     */
    int         write_reg(uint8_t reg, uint8_t val);

    /**
     * Read a register.
     *
     * @param reg       The register to read.
     * @param val       The value read.
     * @return      OK on read success.
     */
    int         read_reg(uint8_t reg, uint8_t &val);

    /**
     * Issue a measurement command.
     *
     * @return      OK if the measurement command was successful.
     */
    int         measure();

    /**
     * Collect the result of the most recent measurement.
     */
    int         collect();

    /* this class has pointer data members, do not allow copying it */
    LPS25H(const LPS25H &);
    LPS25H operator=(const LPS25H &);
};

/*
 * Driver 'main' command.
 */
extern "C" __EXPORT int lps25h_main(int argc, char *argv[]);


LPS25H::LPS25H(device::Device *interface, const char *path) :
    CDev(path),
    ScheduledWorkItem(MODULE_NAME, px4::device_bus_to_wq(interface->get_device_id())),
    _interface(interface),
    _sample_perf(perf_alloc(PC_ELAPSED, "lps25h_read")),
    _comms_errors(perf_alloc(PC_COUNT, "lps25h_comms_errors"))
{
    _interface->set_device_type(DRV_BARO_DEVTYPE_LPS25H);
}

LPS25H::~LPS25H()
{
    /* make sure we are truly inactive */
    stop();

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

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

    // free perf counters
    perf_free(_sample_perf);
    perf_free(_comms_errors);

    delete _interface;
}

int
LPS25H::init()
{
    int ret;

    ret = CDev::init();

    if (ret != OK) {
        PX4_DEBUG("CDev init failed");
        goto out;
    }

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

    if (_reports == nullptr) {
        PX4_DEBUG("can't get memory for reports");
        ret = -ENOMEM;
        goto out;
    }

    if (reset() != OK) {
        goto out;
    }

    /* register alternate interfaces if we have to */
    _class_instance = register_class_devname(BARO_BASE_DEVICE_PATH);

    ret = OK;

out:
    return ret;
}

ssize_t
LPS25H::read(struct file *filp, char *buffer, size_t buflen)
{
    unsigned count = buflen / sizeof(sensor_baro_s);
    sensor_baro_s *brp = reinterpret_cast<sensor_baro_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(brp)) {
                ret += sizeof(*brp);
                brp++;
            }
        }

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

    /* manual measurement - run one conversion */
    /* XXX really it'd be nice to lock against other readers here */
    do {
        _reports->flush();

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

        /* wait for it to complete */
        usleep(LPS25H_CONVERSION_INTERVAL);

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

        if (_reports->get(brp)) {
            ret = sizeof(sensor_baro_s);
        }
    } while (0);

    return ret;
}

int
LPS25H::ioctl(struct file *filp, int cmd, unsigned long arg)
{
    unsigned dummy = 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 = (LPS25H_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 */
                    unsigned interval = (1000000 / arg);

                    /* check against maximum rate */
                    if (interval < (LPS25H_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;
                }
            }
        }

    case SENSORIOCRESET:
        return reset();

    case DEVIOCGDEVICEID:
        return _interface->ioctl(cmd, dummy);

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

void
LPS25H::start()
{
    /* reset the report ring and state machine */
    _collect_phase = false;
    _reports->flush();

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

void
LPS25H::stop()
{
    ScheduleClear();
}

int
LPS25H::reset()
{
    int ret = 0;

    // Power on
    ret = write_reg(ADDR_CTRL_REG1, CTRL_REG1_PD);

    usleep(1000);

    // Reset
    ret = write_reg(ADDR_CTRL_REG2, CTRL_REG2_BOOT | CTRL_REG2_SWRESET);

    usleep(5000);

    // Power on
    ret = write_reg(ADDR_CTRL_REG1, CTRL_REG1_PD);

    usleep(1000);

    return ret;
}

void
LPS25H::Run()
{
    /* collection phase? */
    if (_collect_phase) {

        /* perform collection */
        if (OK != collect()) {
            PX4_DEBUG("collection error");
            /* restart the measurement state machine */
            start();
            return;
        }

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

        /*
         * Is there a collect->measure gap?
         */
        if (_measure_interval > (LPS25H_CONVERSION_INTERVAL)) {

            /* schedule a fresh cycle call when we are ready to measure again */
            ScheduleDelayed(_measure_interval - LPS25H_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(LPS25H_CONVERSION_INTERVAL);
}

int
LPS25H::measure()
{
    int ret;

    /*
     * Send the command to begin a 16-bit measurement.
     */
    ret = write_reg(ADDR_CTRL_REG2, CTRL_REG2_ONE_SHOT);

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

    return ret;
}

int
LPS25H::collect()
{
#pragma pack(push, 1)
    struct {
        uint8_t     status;
        uint8_t     p_xl, p_l, p_h;
        int16_t     t;
    } report;
#pragma pack(pop)

    int ret;

    perf_begin(_sample_perf);
    sensor_baro_s new_report;
    bool sensor_is_onboard = false;

    /* this should be fairly close to the end of the measurement, so the best approximation of the time */
    new_report.timestamp = hrt_absolute_time();
    new_report.error_count = perf_event_count(_comms_errors);

    /*
     * @note  We could read the status register 1 here, which could tell us that
     *        we were too early and that the output registers are still being
     *        written.  In the common case that would just slow us down, and
     *        we're better off just never being early.
     */

    /* get measurements from the device : MSB enables register address auto-increment */
    ret = _interface->read(ADDR_STATUS_REG | (1 << 7), (uint8_t *)&report, sizeof(report));

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

    /* get measurements from the device */
    new_report.temperature = 42.5f + (report.t / 480);

    /* raw pressure */
    uint32_t raw = report.p_xl + (report.p_l << 8) + (report.p_h << 16);

    /* Pressure and MSL in mBar */
    float p = raw / 4096.0f;

    new_report.pressure = p;

    /* get device ID */
    new_report.device_id = _interface->get_device_id();

    if (_baro_topic != nullptr) {
        /* publish it */
        orb_publish(ORB_ID(sensor_baro), _baro_topic, &new_report);

    } else {
        _baro_topic = orb_advertise_multi(ORB_ID(sensor_baro), &new_report,
                          &_orb_class_instance, (sensor_is_onboard) ? ORB_PRIO_HIGH : ORB_PRIO_MAX);

        if (_baro_topic == nullptr) {
            PX4_DEBUG("ADVERT FAIL");
        }
    }

    _last_report = new_report;

    /* post a report to the ring */
    _reports->force(&new_report);

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


    ret = OK;

    perf_end(_sample_perf);
    return ret;
}

int
LPS25H::write_reg(uint8_t reg, uint8_t val)
{
    uint8_t buf = val;
    return _interface->write(reg, &buf, 1);
}

int
LPS25H::read_reg(uint8_t reg, uint8_t &val)
{
    uint8_t buf = val;
    int ret = _interface->read(reg, &buf, 1);
    val = buf;
    return ret;
}

void
LPS25H::print_info()
{
    perf_print_counter(_sample_perf);
    perf_print_counter(_comms_errors);
    printf("poll interval:  %u \n", _measure_interval);
    print_message(_last_report);

    _reports->print_info("report queue");
}

/**
 * Local functions in support of the shell command.
 */
namespace lps25h
{

/*
  list of supported bus configurations
 */
struct lps25h_bus_option {
    enum LPS25H_BUS busid;
    const char *devpath;
    LPS25H_constructor interface_constructor;
    uint8_t busnum;
    LPS25H  *dev;
} bus_options[] = {
    { LPS25H_BUS_I2C_EXTERNAL, "/dev/lps25h_ext", &LPS25H_I2C_interface, PX4_I2C_BUS_EXPANSION, NULL },
#ifdef PX4_I2C_BUS_EXPANSION1
    { LPS25H_BUS_I2C_EXTERNAL, "/dev/lps25h_ext1", &LPS25H_I2C_interface, PX4_I2C_BUS_EXPANSION1, NULL },
#endif
#ifdef PX4_I2C_BUS_EXPANSION2
    { LPS25H_BUS_I2C_EXTERNAL, "/dev/lps25h_ext2", &LPS25H_I2C_interface, PX4_I2C_BUS_EXPANSION2, NULL },
#endif
#ifdef PX4_I2C_BUS_ONBOARD
    { LPS25H_BUS_I2C_INTERNAL, "/dev/lps25h_int", &LPS25H_I2C_interface, PX4_I2C_BUS_ONBOARD, NULL },
#endif
#ifdef PX4_SPIDEV_HMC
    { LPS25H_BUS_SPI, "/dev/lps25h_spi", &LPS25H_SPI_interface, PX4_SPI_BUS_SENSORS, NULL },
#endif
};
#define NUM_BUS_OPTIONS (sizeof(bus_options)/sizeof(bus_options[0]))

void    start(enum LPS25H_BUS busid);
bool    start_bus(struct lps25h_bus_option &bus);
struct lps25h_bus_option &find_bus(enum LPS25H_BUS busid);
void    test(enum LPS25H_BUS busid);
void    reset(enum LPS25H_BUS busid);
void    info();
void    usage();

/**
 * start driver for a specific bus option
 */
bool
start_bus(struct lps25h_bus_option &bus)
{
    if (bus.dev != nullptr) {
        errx(1, "bus option already started");
    }

    device::Device *interface = bus.interface_constructor(bus.busnum);

    if (interface->init() != OK) {
        delete interface;
        warnx("no device on bus %u", (unsigned)bus.busid);
        return false;
    }

    bus.dev = new LPS25H(interface, bus.devpath);

    if (bus.dev != nullptr && OK != bus.dev->init()) {
        delete bus.dev;
        bus.dev = NULL;
        return false;
    }

    int fd = open(bus.devpath, O_RDONLY);

    /* set the poll rate to default, starts automatic data collection */
    if (fd == -1) {
        errx(1, "can't open baro device");
    }

    if (ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT) < 0) {
        close(fd);
        errx(1, "failed setting default poll rate");
    }

    close(fd);

    return true;
}


/**
 * Start the driver.
 *
 * This function call only returns once the driver
 * is either successfully up and running or failed to start.
 */
void
start(enum LPS25H_BUS busid)
{
    bool started = false;

    for (unsigned i = 0; i < NUM_BUS_OPTIONS; i++) {
        if (busid == LPS25H_BUS_ALL && bus_options[i].dev != NULL) {
            // this device is already started
            continue;
        }

        if (busid != LPS25H_BUS_ALL && bus_options[i].busid != busid) {
            // not the one that is asked for
            continue;
        }

        started |= start_bus(bus_options[i]);
    }

    if (!started) {
        exit(1);
    }
}

/**
 * find a bus structure for a busid
 */
struct lps25h_bus_option &find_bus(enum LPS25H_BUS busid)
{
    for (unsigned i = 0; i < NUM_BUS_OPTIONS; i++) {
        if ((busid == LPS25H_BUS_ALL ||
             busid == bus_options[i].busid) && bus_options[i].dev != NULL) {
            return bus_options[i];
        }
    }

    errx(1, "bus %u not started", (unsigned)busid);
}


/**
 * Perform some basic functional tests on the driver;
 * make sure we can collect data from the sensor in polled
 * and automatic modes.
 */
void
test(enum LPS25H_BUS busid)
{
    struct lps25h_bus_option &bus = find_bus(busid);
    sensor_baro_s report;
    ssize_t sz;
    int ret;

    int fd;

    fd = open(bus.devpath, O_RDONLY);

    if (fd < 0) {
        err(1, "open failed (try 'lps25h start' if the driver is not running)");
    }

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

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

    print_message(report);

    /* 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");
        }

        print_message(report);
    }

    close(fd);
    errx(0, "PASS");
}

/**
 * Reset the driver.
 */
void
reset(enum LPS25H_BUS busid)
{
    struct lps25h_bus_option &bus = find_bus(busid);
    const char *path = bus.devpath;

    int fd = open(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()
{
    for (uint8_t i = 0; i < NUM_BUS_OPTIONS; i++) {
        struct lps25h_bus_option &bus = bus_options[i];

        if (bus.dev != nullptr) {
            warnx("%s", bus.devpath);
            bus.dev->print_info();
        }
    }

    exit(0);
}

void
usage()
{
    warnx("missing command: try 'start', 'info', 'test', 'reset'");
    warnx("options:");
    warnx("    -X    (external I2C bus)");
    warnx("    -I    (internal I2C bus)");
    warnx("    -S    (external SPI bus)");
    warnx("    -s    (internal SPI bus)");
}

} // namespace

int
lps25h_main(int argc, char *argv[])
{
    enum LPS25H_BUS busid = LPS25H_BUS_ALL;

    int myoptind = 1;
    int ch;
    const char *myoptarg = nullptr;

    while ((ch = px4_getopt(argc, argv, "XIS:", &myoptind, &myoptarg)) != EOF) {
        switch (ch) {
#if (PX4_I2C_BUS_ONBOARD || PX4_SPIDEV_HMC)

        case 'I':
            busid = LPS25H_BUS_I2C_INTERNAL;
            break;
#endif

        case 'X':
            busid = LPS25H_BUS_I2C_EXTERNAL;
            break;

        case 'S':
            busid = LPS25H_BUS_SPI;
            break;

        default:
            lps25h::usage();
            exit(0);
        }
    }

    if (myoptind >= argc) {
        lps25h::usage();
        exit(0);
    }

    const char *verb = argv[myoptind];

    /*
     * Start/load the driver.
     */
    if (!strcmp(verb, "start")) {
        lps25h::start(busid);
    }

    /*
     * Test the driver/device.
     */
    if (!strcmp(verb, "test")) {
        lps25h::test(busid);
    }

    /*
     * Reset the driver.
     */
    if (!strcmp(verb, "reset")) {
        lps25h::reset(busid);
    }

    /*
     * Print driver information.
     */
    if (!strcmp(verb, "info")) {
        lps25h::info();
    }

    errx(1, "unrecognised command, try 'start', 'test', 'reset' or 'info'");
}