leddar_one.cpp

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 * modification, are permitted provided that the following conditions
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#include <stdlib.h>
#include <string.h>
#include <termios.h>

#include <arch/board/board.h>
#include <drivers/device/device.h>
#include <drivers/device/ringbuffer.h>
#include <drivers/drv_hrt.h>
#include <lib/drivers/rangefinder/PX4Rangefinder.hpp>
#include <perf/perf_counter.h>
#include <px4_platform_common/px4_config.h>
#include <px4_platform_common/defines.h>
#include <px4_platform_common/getopt.h>
#include <px4_platform_common/module.h>
#include <px4_platform_common/px4_work_queue/ScheduledWorkItem.hpp>
#include <uORB/topics/distance_sensor.h>

using namespace time_literals;

#define DEVICE_PATH                     "/dev/LeddarOne"
#define LEDDAR_ONE_DEFAULT_SERIAL_PORT  "/dev/ttyS3"

#define LEDDAR_ONE_FIELD_OF_VIEW        (0.105f) // 6 deg cone angle.

#define LEDDAR_ONE_MAX_DISTANCE         40.0f
#define LEDDAR_ONE_MIN_DISTANCE         0.01f

#define LEDDAR_ONE_MEASURE_INTERVAL     100_ms // 10Hz

#define MODBUS_SLAVE_ADDRESS            0x01
#define MODBUS_READING_FUNCTION         0x04
#define READING_START_ADDR              0x14
#define READING_LEN                     0xA

static const uint8_t request_reading_msg[] = {
    MODBUS_SLAVE_ADDRESS,
    MODBUS_READING_FUNCTION,
    0, /* starting addr high byte */
    READING_START_ADDR,
    0, /* number of bytes to read high byte */
    READING_LEN,
    0x30, /* CRC low */
    0x09 /* CRC high */
};

struct __attribute__((__packed__)) reading_msg {
    uint8_t slave_addr;
    uint8_t function;
    uint8_t len;
    uint8_t low_timestamp_high_byte;
    uint8_t low_timestamp_low_byte;
    uint8_t high_timestamp_high_byte;
    uint8_t high_timestamp_low_byte;
    uint8_t temp_high;
    uint8_t temp_low;
    uint8_t num_detections_high_byte;
    uint8_t num_detections_low_byte;
    uint8_t first_dist_high_byte;
    uint8_t first_dist_low_byte;
    uint8_t first_amplitude_high_byte;
    uint8_t first_amplitude_low_byte;
    uint8_t second_dist_high_byte;
    uint8_t second_dist_low_byte;
    uint8_t second_amplitude_high_byte;
    uint8_t second_amplitude_low_byte;
    uint8_t third_dist_high_byte;
    uint8_t third_dist_low_byte;
    uint8_t third_amplitude_high_byte;
    uint8_t third_amplitude_low_byte;
    uint16_t crc; /* little-endian */
};

class LeddarOne : public cdev::CDev, public px4::ScheduledWorkItem
{
public:
    LeddarOne(const char *device_path,
          const char *serial_port = LEDDAR_ONE_DEFAULT_SERIAL_PORT,
          const uint8_t device_orientation = distance_sensor_s::ROTATION_DOWNWARD_FACING);
    virtual ~LeddarOne();

    virtual int init() override;

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

    /**
     * Initialise the automatic measurement state machine and start it.
     */
    void start();

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

private:

    /**
     * Calculates the 16 byte crc value for the data frame.
     * @param data_frame The data frame to compute a checksum for.
     * @param crc16_length The length of the data frame.
     */
    uint16_t crc16_calc(const unsigned char *data_frame, const uint8_t crc16_length);

    /**
     * Reads the data measrurement from serial UART.
     */
    int collect();

    /**
     * Sends a data request message to the sensor.
     */
    int measure();

    /**
     * Opens and configures the UART serial communications port.
     * @param speed The baudrate (speed) to configure the serial UART port.
     */
    int open_serial_port(const speed_t speed = B115200);

    void Run() override;

    const char *_serial_port{nullptr};

    PX4Rangefinder _px4_rangefinder;

    int _file_descriptor{-1};
    int _orb_class_instance{-1};

    uint8_t _buffer[sizeof(reading_msg)];
    uint8_t _buffer_len{0};

    hrt_abstime _measurement_time{0};

    perf_counter_t _comms_error{perf_alloc(PC_COUNT, "leddar_one_comms_error")};
    perf_counter_t _sample_perf{perf_alloc(PC_ELAPSED, "leddar_one_sample")};
};

LeddarOne::LeddarOne(const char *device_path, const char *serial_port, uint8_t device_orientation):
    CDev(device_path),
    ScheduledWorkItem(MODULE_NAME, px4::serial_port_to_wq(serial_port)),
    _px4_rangefinder(0 /* device id not yet used */, ORB_PRIO_DEFAULT, device_orientation)
{
    _serial_port = strdup(serial_port);

    _px4_rangefinder.set_device_type(distance_sensor_s::MAV_DISTANCE_SENSOR_LASER);
    _px4_rangefinder.set_max_distance(LEDDAR_ONE_MAX_DISTANCE);
    _px4_rangefinder.set_min_distance(LEDDAR_ONE_MIN_DISTANCE);
    _px4_rangefinder.set_fov(LEDDAR_ONE_FIELD_OF_VIEW);
    _px4_rangefinder.set_orientation(device_orientation);
}

LeddarOne::~LeddarOne()
{
    stop();
    free((char *)_serial_port);
    perf_free(_comms_error);
    perf_free(_sample_perf);
}

uint16_t
LeddarOne::crc16_calc(const unsigned char *data_frame, const uint8_t crc16_length)
{
    uint16_t crc = 0xFFFF;

    for (uint8_t i = 0; i < crc16_length; i++) {
        crc ^= data_frame[i];

        for (uint8_t j = 0; j < 8; j++) {
            if (crc & 1) {
                crc = (crc >> 1) ^ 0xA001;

            } else {
                crc >>= 1;
            }
        }
    }

    return crc;
}

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

    const int buffer_size = sizeof(_buffer);
    const int message_size = sizeof(reading_msg);

    int bytes_read = ::read(_file_descriptor, _buffer + _buffer_len, buffer_size - _buffer_len);

    if (bytes_read < 1) {
        // Trigger a new measurement.
        return measure();
    }

    _buffer_len += bytes_read;

    if (_buffer_len < message_size) {
        // Return on next scheduled cycle to collect remaining data.
        return PX4_OK;
    }

    reading_msg *msg {nullptr};
    msg = (reading_msg *)_buffer;

    if (msg->slave_addr != MODBUS_SLAVE_ADDRESS ||
        msg->function != MODBUS_READING_FUNCTION) {
        PX4_ERR("slave address or function read error");
        perf_count(_comms_error);
        perf_end(_sample_perf);
        return measure();
    }

    const uint16_t crc16 = crc16_calc(_buffer, buffer_size - 2);

    if (crc16 != msg->crc) {
        PX4_ERR("crc error");
        perf_count(_comms_error);
        perf_end(_sample_perf);
        return measure();
    }

    // NOTE: little-endian support only.
    uint16_t distance_mm = (msg->first_dist_high_byte << 8 | msg->first_dist_low_byte);
    float distance_m = static_cast<float>(distance_mm) / 1000.0f;

    // @TODO - implement a meaningful signal quality value.
    int8_t signal_quality = -1;

    _px4_rangefinder.update(_measurement_time, distance_m, signal_quality);

    perf_end(_sample_perf);

    // Trigger the next measurement.
    return measure();;
}

int
LeddarOne::init()
{
    if (CDev::init()) {
        PX4_ERR("Unable to initialize device");
        return PX4_ERROR;
    }

    if (open_serial_port() != PX4_OK) {
        return PX4_ERROR;
    }

    hrt_abstime time_now = hrt_absolute_time();

    const hrt_abstime timeout_usec = time_now + 500000_us; // 0.5sec

    while (time_now < timeout_usec) {
        if (measure() == PX4_OK) {
            px4_usleep(LEDDAR_ONE_MEASURE_INTERVAL);

            if (collect() == PX4_OK) {
                // The file descriptor can only be accessed by the process that opened it,
                // so closing here allows the port to be opened from scheduled work queue.
                stop();
                return PX4_OK;
            }
        }

        px4_usleep(1000);
        time_now = hrt_absolute_time();
    }

    PX4_ERR("No readings from LeddarOne");
    return PX4_ERROR;
}

int
LeddarOne::measure()
{
    // Flush the receive buffer.
    tcflush(_file_descriptor, TCIFLUSH);

    int num_bytes = ::write(_file_descriptor, request_reading_msg, sizeof(request_reading_msg));

    if (num_bytes != sizeof(request_reading_msg)) {
        PX4_INFO("measurement error: %i, errno: %i", num_bytes, errno);
        return PX4_ERROR;
    }

    _measurement_time = hrt_absolute_time();
    _buffer_len = 0;
    return PX4_OK;
}

int
LeddarOne::open_serial_port(const speed_t speed)
{
    // File descriptor already initialized?
    if (_file_descriptor > 0) {
        // PX4_INFO("serial port already open");
        return PX4_OK;
    }

    // Configure port flags for read/write, non-controlling, non-blocking.
    int flags = (O_RDWR | O_NOCTTY | O_NONBLOCK);

    // Open the serial port.
    _file_descriptor = ::open(_serial_port, flags);

    if (_file_descriptor < 0) {
        PX4_ERR("open failed (%i)", errno);
        return PX4_ERROR;
    }

    termios uart_config = {};

    // Store the current port configuration. attributes.
    if (tcgetattr(_file_descriptor, &uart_config)) {
        PX4_ERR("Unable to get termios from %s.", _serial_port);
        ::close(_file_descriptor);
        _file_descriptor = -1;
        return PX4_ERROR;
    }

    // Clear: data bit size, two stop bits, parity, hardware flow control.
    uart_config.c_cflag &= ~(CSIZE | CSTOPB | PARENB | CRTSCTS);

    // Set: 8 data bits, enable receiver, ignore modem status lines.
    uart_config.c_cflag |= (CS8 | CREAD | CLOCAL);

    // Clear: echo, echo new line, canonical input and extended input.
    uart_config.c_lflag &= (ECHO | ECHONL | ICANON | IEXTEN);

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

    // Set the input baud rate in the uart_config struct.
    int termios_state = cfsetispeed(&uart_config, speed);

    if (termios_state < 0) {
        PX4_ERR("CFG: %d ISPD", termios_state);
        ::close(_file_descriptor);
        return PX4_ERROR;
    }

    // Set the output baud rate in the uart_config struct.
    termios_state = cfsetospeed(&uart_config, speed);

    if (termios_state < 0) {
        PX4_ERR("CFG: %d OSPD", termios_state);
        ::close(_file_descriptor);
        return PX4_ERROR;
    }

    // Apply the modified port attributes.
    termios_state = tcsetattr(_file_descriptor, TCSANOW, &uart_config);

    if (termios_state < 0) {
        PX4_ERR("baud %d ATTR", termios_state);
        ::close(_file_descriptor);
        return PX4_ERROR;
    }

    // Flush the hardware buffers.
    tcflush(_file_descriptor, TCIOFLUSH);

    PX4_INFO("opened UART port %s", _serial_port);
    return PX4_OK;
}

void
LeddarOne::print_info()
{
    perf_print_counter(_comms_error);
    perf_print_counter(_sample_perf);
    PX4_INFO("measure interval:  %u msec", static_cast<uint16_t>(LEDDAR_ONE_MEASURE_INTERVAL));
}

void
LeddarOne::Run()
{
    // Ensure the serial port is open.
    open_serial_port();

    collect();
}

void
LeddarOne::start()
{
    // Schedule the driver at regular intervals.
    ScheduleOnInterval(LEDDAR_ONE_MEASURE_INTERVAL, LEDDAR_ONE_MEASURE_INTERVAL);
    PX4_INFO("driver started");
}

void
LeddarOne::stop()
{
    // Ensure the serial port is closed.
    ::close(_file_descriptor);
    _file_descriptor = -1;

    // Clear the work queue schedule.
    ScheduleClear();
}


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

LeddarOne *g_dev;

int start(const char *port = LEDDAR_ONE_DEFAULT_SERIAL_PORT,
      const uint8_t rotation = distance_sensor_s::ROTATION_DOWNWARD_FACING);
int status();
int stop();
int test(const char *port = LEDDAR_ONE_DEFAULT_SERIAL_PORT);
int usage();

int start(const char *port, const uint8_t rotation)
{
    if (g_dev != nullptr) {
        PX4_ERR("already started");
        return PX4_ERROR;
    }

    g_dev = new LeddarOne(DEVICE_PATH, port, rotation);

    if (g_dev == nullptr) {
        PX4_ERR("object instantiate failed");
        delete g_dev;
        return PX4_ERROR;
    }

    // Initialize the sensor.
    if (g_dev->init() != PX4_OK) {
        PX4_ERR("driver start failed");
        delete g_dev;
        g_dev = nullptr;
        return PX4_ERROR;
    }

    // Start the driver.
    g_dev->start();
    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(const char *port)
{
    // Configure port flags for read/write, non-controlling, non-blocking.
    int flags = (O_RDWR | O_NOCTTY | O_NONBLOCK);

    // Open the serial port.
    int fd = ::open(port, flags);

    if (fd < 0) {
        PX4_ERR("Unable to open %s", port);
        return PX4_ERROR;
    }

    ssize_t num_bytes = ::write(fd, request_reading_msg, sizeof(request_reading_msg));

    if (num_bytes != sizeof(request_reading_msg)) {
        PX4_INFO("serial port write failed: %i, errno: %i", num_bytes, errno);
        return PX4_ERROR;
    }

    px4_usleep(LEDDAR_ONE_MEASURE_INTERVAL);

    uint8_t buffer[sizeof(reading_msg)];

    num_bytes = ::read(fd, buffer, sizeof(reading_msg));

    if (num_bytes != sizeof(reading_msg)) {
        PX4_ERR("Data not available at %s", port);
        return PX4_ERROR;
    }

    close(fd);

    PX4_INFO("PASS");
    return PX4_OK;
}

int
usage()
{
    PRINT_MODULE_DESCRIPTION(
        R"DESCR_STR(
### Description

Serial bus driver for the LeddarOne LiDAR.

Most boards are configured to enable/start the driver on a specified UART using the SENS_LEDDAR1_CFG parameter.

Setup/usage information: https://docs.px4.io/en/sensor/leddar_one.html

### Examples

Attempt to start driver on a specified serial device.
$ leddar_one start -d /dev/ttyS1
Stop driver
$ leddar_one stop
)DESCR_STR");

    PRINT_MODULE_USAGE_NAME("leddar_one", "driver");
    PRINT_MODULE_USAGE_SUBCATEGORY("distance_sensor");
    PRINT_MODULE_USAGE_COMMAND_DESCR("start","Start driver");
    PRINT_MODULE_USAGE_PARAM_STRING('d', nullptr, nullptr, "Serial device", false);
    PRINT_MODULE_USAGE_PARAM_INT('r', 25, 1, 25, "Sensor rotation - downward facing by default", true);
    PRINT_MODULE_USAGE_COMMAND_DESCR("stop","Stop driver");
    PRINT_MODULE_USAGE_COMMAND_DESCR("test","Test driver (basic functional tests)");
    return PX4_OK;
}

} // namespace

extern "C" __EXPORT int leddar_one_main(int argc, char *argv[])
{
    const char *myoptarg = nullptr;

    int ch = 0;
    int myoptind = 1;

    const char *port = LEDDAR_ONE_DEFAULT_SERIAL_PORT;
    uint8_t rotation = distance_sensor_s::ROTATION_DOWNWARD_FACING;

    while ((ch = px4_getopt(argc, argv, "d:r", &myoptind, &myoptarg)) != EOF) {
        switch (ch) {
        case 'd':
            port = myoptarg;
            break;

        case 'r':
            rotation = (uint8_t)atoi(myoptarg);
            break;

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

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

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

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

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

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

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