mb12xx.cpp

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/**
 * @file mb12xx.cpp
 * @author Greg Hulands
 * @author Jon Verbeke <jon.verbeke@kuleuven.be>
 *
 * Driver for the Maxbotix sonar range finders connected via I2C.
 */

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

#include <board_config.h>
#include <containers/Array.hpp>
#include <drivers/device/device.h>
#include <drivers/device/i2c.h>
#include <drivers/device/ringbuffer.h>
#include <drivers/drv_hrt.h>
#include <drivers/drv_range_finder.h>
#include <perf/perf_counter.h>
#include <px4_platform_common/px4_config.h>
#include <px4_platform_common/getopt.h>
#include <px4_platform_common/module_params.h>
#include <px4_platform_common/px4_work_queue/ScheduledWorkItem.hpp>
#include <uORB/uORB.h>
#include <uORB/topics/distance_sensor.h>

using namespace time_literals;

/* Configuration Constants */
#define MB12XX_BASE_ADDR                        0x70   // 7-bit address is 0x70 = 112. 8-bit address is 0xE0 = 224.
#define MB12XX_MIN_ADDR                         0x5A   // 7-bit address is 0x5A = 90.  8-bit address is 0xB4 = 180.
#define MB12XX_BUS_DEFAULT                      PX4_I2C_BUS_EXPANSION
#define MB12XX_BUS_SPEED                        100000 // 100kHz bus speed.
#define MB12XX_DEVICE_PATH                      "/dev/mb12xx"

/* MB12xx Registers addresses */
#define MB12XX_TAKE_RANGE_REG                   0x51 // Measure range Register.
#define MB12XX_SET_ADDRESS_1                    0xAA // Change address 1 Register.
#define MB12XX_SET_ADDRESS_2                    0xA5 // Change address 2 Register.

/* Device limits */
#define MB12XX_MIN_DISTANCE                     (0.20f)
#define MB12XX_MAX_DISTANCE                     (7.65f)

#define MB12XX_MEASURE_INTERVAL                 100_ms // 60ms minimum for one sonar.
#define MB12XX_INTERVAL_BETWEEN_SUCCESIVE_FIRES 100_ms // 30ms minimum between each sonar measurement (watch out for interference!).

class MB12XX : public device::I2C, public ModuleParams, public px4::ScheduledWorkItem
{
public:
    MB12XX(const int bus = MB12XX_BUS_DEFAULT);
    virtual ~MB12XX();

    virtual int init() override;

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

    /**
     * Sets a new device address.
     * @param address The new sensor address to be set: 200-224 even addresses only.
     * @return Returns PX4_OK iff successful, PX4_ERROR otherwise.
     */
    int set_address(const uint8_t address = MB12XX_BASE_ADDR);

    /**
     * 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();

protected:

private:

    /**
     * Collects the most recent sensor measurement data from the i2c bus.
     */
    int collect();

    /**
     * Gets the current sensor rotation value.
     */
    int get_sensor_rotation(const size_t index);

    /**
     * Sends an i2c measure command to start the next sonar ping.
     */
    int measure();

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

    px4::Array<uint8_t, RANGE_FINDER_MAX_SENSORS> _sensor_addresses {};
    px4::Array<uint8_t, RANGE_FINDER_MAX_SENSORS> _sensor_rotations {};

    int _measure_interval{MB12XX_MEASURE_INTERVAL}; // Initialize the measure interval for a single sensor.
    int _orb_class_instance{-1};

    size_t _sensor_index{0};    // Initialize counter for cycling i2c adresses to zero.

    size_t _sensor_count{0};

    orb_advert_t _distance_sensor_topic{nullptr};

    perf_counter_t _comms_error{perf_alloc(PC_ELAPSED, "mb12xx_comms_error")};
    perf_counter_t _sample_perf{perf_alloc(PC_COUNT, "mb12xx_sample_perf")};

    DEFINE_PARAMETERS(
        (ParamInt<px4::params::SENS_EN_MB12XX>)   _p_sensor_enabled,
        (ParamInt<px4::params::SENS_MB12_0_ROT>)  _p_sensor0_rot,
        (ParamInt<px4::params::SENS_MB12_1_ROT>)  _p_sensor1_rot,
        (ParamInt<px4::params::SENS_MB12_2_ROT>)  _p_sensor2_rot,
        (ParamInt<px4::params::SENS_MB12_3_ROT>)  _p_sensor3_rot,
        (ParamInt<px4::params::SENS_MB12_4_ROT>)  _p_sensor4_rot,
        (ParamInt<px4::params::SENS_MB12_5_ROT>)  _p_sensor5_rot,
        (ParamInt<px4::params::SENS_MB12_6_ROT>)  _p_sensor6_rot,
        (ParamInt<px4::params::SENS_MB12_7_ROT>)  _p_sensor7_rot,
        (ParamInt<px4::params::SENS_MB12_8_ROT>)  _p_sensor8_rot,
        (ParamInt<px4::params::SENS_MB12_9_ROT>)  _p_sensor9_rot,
        (ParamInt<px4::params::SENS_MB12_10_ROT>) _p_sensor10_rot,
        (ParamInt<px4::params::SENS_MB12_11_ROT>) _p_sensor11_rot
    );
};

MB12XX::MB12XX(const int bus) :
    I2C("MB12xx", MB12XX_DEVICE_PATH, bus, MB12XX_BASE_ADDR, MB12XX_BUS_SPEED),
    ModuleParams(nullptr),
    ScheduledWorkItem(MODULE_NAME, px4::device_bus_to_wq(get_device_id()))
{
}

MB12XX::~MB12XX()
{
    // Ensure we are truly inactive.
    stop();

    // Unadvertise the distance sensor topic.
    if (_distance_sensor_topic != nullptr) {
        orb_unadvertise(_distance_sensor_topic);
    }

    // Free perf counters.
    perf_free(_comms_error);
    perf_free(_sample_perf);
}

int
MB12XX::collect()
{
    perf_begin(_sample_perf);
    uint8_t val[2] = {};

    // Increment i2c adress to next sensor.
    _sensor_index++;
    _sensor_index %= _sensor_count;

    // Set the sensor i2c adress for the active cycle.
    set_device_address(_sensor_addresses[_sensor_index]);

    // Transfer data from the bus.
    int ret_val = transfer(nullptr, 0, &val[0], 2);

    if (ret_val < 0) {
        PX4_ERR("sensor %i read failed, address: 0x%02X", _sensor_index, get_device_address());
        perf_count(_comms_error);
        perf_end(_sample_perf);
        return ret_val;
    }

    uint16_t distance_cm = val[0] << 8 | val[1];
    float distance_m = static_cast<float>(distance_cm) * 1e-2f;

    distance_sensor_s report;
    report.current_distance = distance_m;
    report.id               = _sensor_addresses[_sensor_index];
    report.max_distance     = MB12XX_MAX_DISTANCE;
    report.min_distance     = MB12XX_MIN_DISTANCE;
    report.orientation      = _sensor_rotations[_sensor_index];
    report.signal_quality   = -1;
    report.timestamp        = hrt_absolute_time();
    report.type             = distance_sensor_s::MAV_DISTANCE_SENSOR_ULTRASOUND;
    report.variance         = 0.0f;

    int instance_id;
    orb_publish_auto(ORB_ID(distance_sensor), &_distance_sensor_topic, &report, &instance_id, ORB_PRIO_DEFAULT);

    // Begin the next measurement.
    if (measure() != PX4_OK) {
        PX4_INFO("sensor %i measurement error, address 0x%02X", _sensor_index, get_device_address());
        perf_count(_comms_error);
        perf_end(_sample_perf);
        return ret_val;
    }

    perf_end(_sample_perf);
    return PX4_OK;
}

int
MB12XX::get_sensor_rotation(const size_t index)
{
    switch (index) {
    case 0: return _p_sensor0_rot.get();

    case 1: return _p_sensor1_rot.get();

    case 2: return _p_sensor2_rot.get();

    case 3: return _p_sensor3_rot.get();

    case 4: return _p_sensor4_rot.get();

    case 5: return _p_sensor5_rot.get();

    case 6: return _p_sensor6_rot.get();

    case 7: return _p_sensor7_rot.get();

    case 8: return _p_sensor8_rot.get();

    case 9: return _p_sensor9_rot.get();

    case 10: return _p_sensor10_rot.get();

    case 11: return _p_sensor11_rot.get();

    default: return PX4_ERROR;
    }
}

int
MB12XX::init()
{
    if (_p_sensor_enabled.get() == 0) {
        PX4_WARN("disabled");
        return PX4_ERROR;
    }

    // Initialize the I2C device
    if (I2C::init() != OK) {
        return PX4_ERROR;
    }

    // Check for connected rangefinders on each i2c port by decrementing from the base address,
    // (MB12XX_BASE_ADDR = 112, MB12XX_MIN_ADDR = 90).
    for (uint8_t address = MB12XX_BASE_ADDR; address > MB12XX_MIN_ADDR ; address--) {
        set_device_address(address);

        if (measure() == PX4_OK) {
            // Store I2C address
            _sensor_addresses[_sensor_count] = address;
            _sensor_rotations[_sensor_count] = get_sensor_rotation(_sensor_count);
            _sensor_count++;

            PX4_INFO("sensor %i at address 0x%02X added", _sensor_count, get_device_address());

            if (_sensor_count >= RANGE_FINDER_MAX_SENSORS) {
                break;
            }

            px4_usleep(_measure_interval);
        }
    }

    // Return an error if no sensors were detected.
    if (_sensor_count == 0) {
        PX4_ERR("no sensors discovered");
        return PX4_ERROR;
    }

    // If more than one sonar is detected, adjust the meaure interval to avoid sensor interference.
    if (_sensor_count > 1) {
        _measure_interval = MB12XX_INTERVAL_BETWEEN_SUCCESIVE_FIRES;
    }

    PX4_INFO("Total sensors connected: %i", _sensor_count);
    return PX4_OK;
}

int
MB12XX::measure()
{
    // Send the command to take a measurement.
    uint8_t cmd = MB12XX_TAKE_RANGE_REG;
    int ret_val = transfer(&cmd, 1, nullptr, 0);

    return ret_val;
}

void
MB12XX::print_info()
{
    perf_print_counter(_sample_perf);
    perf_print_counter(_comms_error);
    PX4_INFO("poll interval:  %ums", _measure_interval / 1000);

    for (size_t i = 0; i < _sensor_count; i++) {
        PX4_INFO("sensor: %u, address %u", i, _sensor_addresses[i]);
    }
}

void
MB12XX::Run()
{
    // Collect the sensor data.
    if (collect() != PX4_OK) {
        PX4_INFO("collection error");
    }
}

int
MB12XX::set_address(const uint8_t address)
{
    if (_sensor_count > 1) {
        PX4_INFO("multiple sensors are connected");
        return PX4_ERROR;
    }

    if (address < 2    ||
        address == 80  ||
        address == 164 ||
        address == 170 ||
        address > 224) {
        PX4_ERR("incompatible address requested");
        return PX4_ERROR;
    }

    PX4_INFO("requested address: %u", address);

    uint8_t shifted_address = (address << 1);
    uint8_t cmd[3] = {MB12XX_SET_ADDRESS_1, MB12XX_SET_ADDRESS_2, shifted_address};

    if (transfer(cmd, sizeof(cmd), nullptr, 0) != PX4_OK) {
        PX4_INFO("could not set the address");
    }

    set_device_address(address);
    PX4_INFO("device address: %u", get_device_address());
    return PX4_OK;
}

void
MB12XX::start()
{
    // Fetch parameter values.
    ModuleParams::updateParams();

    // Schedule the driver cycle at regular intervals.
    ScheduleOnInterval(_measure_interval);
}

void
MB12XX::stop()
{
    ScheduleClear();
}

/**
 * Local functions in support of the shell command.
 */
namespace mb12xx
{

MB12XX  *g_dev;

int reset();
int set_address(const uint8_t address = MB12XX_BASE_ADDR);
int start();
int start_bus(const int i2c_bus = MB12XX_BUS_DEFAULT);
int status();
int stop();
int test();
int usage();

/**
 * Reset the driver.
 */
int
reset()
{
    PX4_INFO("driver resetting");
    stop();
    start();
    return PX4_OK;
}

int
set_address(const uint8_t address)
{
    if (g_dev != nullptr) {
        if (g_dev->set_address(address) != PX4_OK) {
            PX4_ERR("address not set");
            return PX4_ERROR;
        }
    }

    reset();
    return PX4_OK;
}

/**
 * Attempt to start driver on all available I2C busses.
 *
 * This function will return as soon as the first sensor
 * is detected on one of the available busses or if no
 * sensors are detected.
 */
int
start()
{
    if (g_dev != nullptr) {
        PX4_ERR("already started");
        return PX4_ERROR;
    }

    for (unsigned i = 0; i < NUM_I2C_BUS_OPTIONS; i++) {
        if (start_bus(i2c_bus_options[i]) == PX4_OK) {
            return PX4_OK;
        }
    }

    return PX4_ERROR;
}

/**
 * Start the driver on a specific bus.
 *
 * This function only returns if the sensor is up and running
 * or could not be detected successfully.
 */
int
start_bus(const int i2c_bus)
{
    if (g_dev != nullptr) {
        PX4_ERR("already started");
        return PX4_OK;
    }

    // Instantiate the driver.
    g_dev = new MB12XX(i2c_bus);

    if (g_dev == nullptr) {
        delete g_dev;
        return PX4_ERROR;
    }

    // Initialize the sensor.
    if (g_dev->init() != PX4_OK) {
        delete g_dev;
        g_dev = nullptr;
        return PX4_ERROR;
    }

    // Start the driver.
    g_dev->start();

    PX4_INFO("driver started");
    return PX4_OK;
}

/**
 * Print the driver status.
 */
int
status()
{
    if (g_dev == nullptr) {
        PX4_ERR("driver not running");
        return PX4_ERROR;
    }

    g_dev->print_info();

    return PX4_OK;
}

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

    PX4_INFO("driver stopped");
    return PX4_OK;
}

/**
 * Perform some basic functional tests on the driver;
 * make sure we can collect data from the sensor in polled
 * and automatic modes.
 */
int
test()
{
    int fd = px4_open(MB12XX_DEVICE_PATH, O_RDONLY);

    if (fd < 0) {
        PX4_ERR("%s open failed (try 'mb12xx start' if the driver is not running)", MB12XX_DEVICE_PATH);
        return PX4_ERROR;
    }

    // Perform a simple demand read.
    distance_sensor_s report {};
    ssize_t sz = read(fd, &report, sizeof(report));

    if (sz != sizeof(report)) {
        PX4_ERR("immediate read failed");
        return PX4_ERROR;
    }

    print_message(report);

    PX4_INFO("PASS");
    return PX4_OK;
}

/**
 * Print information about the driver usage.
 */
int
usage()
{
    PX4_INFO("usage: mb12xx <command> [options]");
    PX4_INFO("options:");
    PX4_INFO("\t-a --all available busses");
    PX4_INFO("\t-b --bus i2cbus (%d)", MB12XX_BUS_DEFAULT);
    PX4_INFO("\t-A --set device address (0-112, 0x00-0x70)");
    PX4_INFO("command:");
    PX4_INFO("\treset|set_address|start|status|stop|test|usage");
    return PX4_OK;
}

} // namespace mb12xx

/**
 * Driver 'main' command.
 */
extern "C" __EXPORT int mb12xx_main(int argc, char *argv[])
{
    const char *myoptarg = nullptr;

    int ch = 0;
    int i2c_bus = MB12XX_BUS_DEFAULT;
    int myoptind = 1;

    uint8_t address = MB12XX_BASE_ADDR;

    bool start_all = false;

    while ((ch = px4_getopt(argc, argv, "abs:", &myoptind, &myoptarg)) != EOF) {
        switch (ch) {
        case 'a':
            start_all = true;
            break;

        case 'b':
            i2c_bus = atoi(myoptarg);
            break;

        case 's':
            address = (uint8_t)atoi(myoptarg);
            break;

        default:
            PX4_WARN("Unknown option!");
            return mb12xx::usage();
        }
    }

    if (myoptind >= argc) {
        return mb12xx::usage();
    }

    // Reset the driver.
    if (!strcmp(argv[myoptind], "reset")) {
        return mb12xx::reset();
    }

    // Set the device I2C address.
    if (!strcmp(argv[myoptind], "set_address")) {
        return mb12xx::set_address(address);
    }

    // Start/load the driver.
    if (!strcmp(argv[myoptind], "start")) {
        if (start_all) {
            return mb12xx::start();

        } else {
            return mb12xx::start_bus(i2c_bus);
        }
    }

    // Print the driver status.
    if (!strcmp(argv[myoptind], "status")) {
        return mb12xx::status();
    }

    // Stop the driver.
    if (!strcmp(argv[myoptind], "stop")) {
        return mb12xx::stop();
    }

    // Test the driver/device.
    if (!strcmp(argv[myoptind], "test")) {
        return mb12xx::test();
    }

    // Print driver usage information.
    return mb12xx::usage();
}