BMI055_accel.cpp

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#include "BMI055_accel.hpp"

/*
  list of registers that will be checked in check_registers(). Note
  that ADDR_WHO_AM_I must be first in the list.
 */
const uint8_t BMI055_accel::_checked_registers[BMI055_ACCEL_NUM_CHECKED_REGISTERS] = {    BMI055_ACC_CHIP_ID,
                                              BMI055_ACC_BW,
                                              BMI055_ACC_RANGE,
                                              BMI055_ACC_INT_EN_1,
                                              BMI055_ACC_INT_MAP_1,
                                             };

BMI055_accel::BMI055_accel(int bus, const char *path_accel, uint32_t device, enum Rotation rotation) :
    BMI055("BMI055_ACCEL", path_accel, bus, device, SPIDEV_MODE3, BMI055_BUS_SPEED, rotation),
    ScheduledWorkItem(MODULE_NAME, px4::device_bus_to_wq(get_device_id())),
    _px4_accel(get_device_id(), (external() ? ORB_PRIO_MAX - 1 : ORB_PRIO_HIGH - 1), rotation),
    _sample_perf(perf_alloc(PC_ELAPSED, "bmi055_accel_read")),
    _bad_transfers(perf_alloc(PC_COUNT, "bmi055_accel_bad_transfers")),
    _bad_registers(perf_alloc(PC_COUNT, "bmi055_accel_bad_registers")),
    _duplicates(perf_alloc(PC_COUNT, "bmi055_accel_duplicates")),
    _got_duplicate(false)
{
    _px4_accel.set_device_type(DRV_ACC_DEVTYPE_BMI055);
}

BMI055_accel::~BMI055_accel()
{
    /* make sure we are truly inactive */
    stop();

    /* delete the perf counter */
    perf_free(_sample_perf);
    perf_free(_bad_transfers);
    perf_free(_bad_registers);
    perf_free(_duplicates);
}

int
BMI055_accel::init()
{
    /* do SPI init (and probe) first */
    int ret = SPI::init();

    /* if probe/setup failed, bail now */
    if (ret != OK) {
        DEVICE_DEBUG("SPI setup failed");
        return ret;
    }

    return reset();
}

int BMI055_accel::reset()
{
    write_reg(BMI055_ACC_SOFTRESET, BMI055_SOFT_RESET); // Soft-reset
    up_udelay(5000);

    write_checked_reg(BMI055_ACC_BW,    BMI055_ACCEL_BW_500); //Write accel bandwidth (DLPF)
    write_checked_reg(BMI055_ACC_RANGE,     BMI055_ACCEL_RANGE_2_G);//Write range
    write_checked_reg(BMI055_ACC_INT_EN_1,      BMI055_ACC_DRDY_INT_EN); //Enable DRDY interrupt
    write_checked_reg(BMI055_ACC_INT_MAP_1,     BMI055_ACC_DRDY_INT1); //Map DRDY interrupt on pin INT1

    set_accel_range(BMI055_ACCEL_DEFAULT_RANGE_G);//set accel range

    //Enable Accelerometer in normal mode
    write_reg(BMI055_ACC_PMU_LPW, BMI055_ACCEL_NORMAL);
    up_udelay(1000);

    uint8_t retries = 10;

    while (retries--) {
        bool all_ok = true;

        for (uint8_t i = 0; i < BMI055_ACCEL_NUM_CHECKED_REGISTERS; i++) {
            if (read_reg(_checked_registers[i]) != _checked_values[i]) {
                write_reg(_checked_registers[i], _checked_values[i]);
                all_ok = false;
            }
        }

        if (all_ok) {
            break;
        }
    }

    return OK;
}

int
BMI055_accel::probe()
{
    /* look for device ID */
    _whoami = read_reg(BMI055_ACC_CHIP_ID);

    // verify product revision
    switch (_whoami) {
    case BMI055_ACC_WHO_AM_I:
        memset(_checked_values, 0, sizeof(_checked_values));
        memset(_checked_bad, 0, sizeof(_checked_bad));
        _checked_values[0] = _whoami;
        _checked_bad[0] = _whoami;
        return OK;
    }

    DEVICE_DEBUG("unexpected whoami 0x%02x", _whoami);
    return -EIO;
}

/*
  deliberately trigger an error in the sensor to trigger recovery
 */
void
BMI055_accel::test_error()
{
    write_reg(BMI055_ACC_SOFTRESET, BMI055_SOFT_RESET);
    ::printf("error triggered\n");
    print_registers();
}

void
BMI055_accel::modify_reg(unsigned reg, uint8_t clearbits, uint8_t setbits)
{
    uint8_t val = read_reg(reg);
    val &= ~clearbits;
    val |= setbits;
    write_checked_reg(reg, val);
}

void
BMI055_accel::write_checked_reg(unsigned reg, uint8_t value)
{
    write_reg(reg, value);

    for (uint8_t i = 0; i < BMI055_ACCEL_NUM_CHECKED_REGISTERS; i++) {
        if (reg == _checked_registers[i]) {
            _checked_values[i] = value;
            _checked_bad[i] = value;
        }
    }
}

int
BMI055_accel::set_accel_range(unsigned max_g)
{
    uint8_t setbits = 0;
    uint8_t clearbits = BMI055_ACCEL_RANGE_2_G | BMI055_ACCEL_RANGE_16_G;
    float lsb_per_g;

    if (max_g == 0) {
        max_g = 16;
    }

    if (max_g <= 2) {
        //max_accel_g = 2;
        setbits |= BMI055_ACCEL_RANGE_2_G;
        lsb_per_g = 1024;

    } else if (max_g <= 4) {
        //max_accel_g = 4;
        setbits |= BMI055_ACCEL_RANGE_4_G;
        lsb_per_g = 512;

    } else if (max_g <= 8) {
        //max_accel_g = 8;
        setbits |= BMI055_ACCEL_RANGE_8_G;
        lsb_per_g = 256;

    } else if (max_g <= 16) {
        //max_accel_g = 16;
        setbits |= BMI055_ACCEL_RANGE_16_G;
        lsb_per_g = 128;

    } else {
        return -EINVAL;
    }

    _px4_accel.set_scale(CONSTANTS_ONE_G / lsb_per_g);

    modify_reg(BMI055_ACC_RANGE, clearbits, setbits);

    return OK;
}

void
BMI055_accel::start()
{
    /* make sure we are stopped first */
    stop();

    /* start polling at the specified rate */
    ScheduleOnInterval(BMI055_ACCEL_DEFAULT_RATE - BMI055_TIMER_REDUCTION, 1000);
}

void
BMI055_accel::stop()
{
    ScheduleClear();
}

void
BMI055_accel::Run()
{
    /* make another measurement */
    measure();
}

void
BMI055_accel::check_registers(void)
{
    uint8_t v;

    if ((v = read_reg(_checked_registers[_checked_next])) !=
        _checked_values[_checked_next]) {
        _checked_bad[_checked_next] = v;

        /*
          if we get the wrong value then we know the SPI bus
          or sensor is very sick. We set _register_wait to 20
          and wait until we have seen 20 good values in a row
          before we consider the sensor to be OK again.
         */
        perf_count(_bad_registers);

        /*
          try to fix the bad register value. We only try to
          fix one per loop to prevent a bad sensor hogging the
          bus.
         */
        if (_register_wait == 0 || _checked_next == 0) {
            // if the product_id is wrong then reset the
            // sensor completely
            write_reg(BMI055_ACC_SOFTRESET, BMI055_SOFT_RESET);
            _reset_wait = hrt_absolute_time() + 10000;
            _checked_next = 0;

        } else {
            write_reg(_checked_registers[_checked_next], _checked_values[_checked_next]);
            // waiting 3ms between register writes seems
            // to raise the chance of the sensor
            // recovering considerably
            _reset_wait = hrt_absolute_time() + 3000;
        }

        _register_wait = 20;
    }

    _checked_next = (_checked_next + 1) % BMI055_ACCEL_NUM_CHECKED_REGISTERS;
}

void
BMI055_accel::measure()
{
    if (hrt_absolute_time() < _reset_wait) {
        // we're waiting for a reset to complete
        return;
    }

    struct Report {
        int16_t     accel_x;
        int16_t     accel_y;
        int16_t     accel_z;
        int8_t     temp;
    } report;

    /* start measuring */
    perf_begin(_sample_perf);

    /*
     * Fetch the full set of measurements from the BMI055 in one pass.
     */
    uint8_t index = 0;
    uint8_t accel_data[8] {};
    accel_data[index] = BMI055_ACC_X_L | DIR_READ;

    const hrt_abstime timestamp_sample = hrt_absolute_time();

    if (OK != transfer(accel_data, accel_data, sizeof(accel_data))) {
        return;
    }

    check_registers();

    /* Extracting accel data from the read data */
    index = 1;
    uint16_t lsb, msb, msblsb;

    lsb = (uint16_t)accel_data[index++];
    uint8_t status_x = (lsb & BMI055_NEW_DATA_MASK);
    msb = (uint16_t)accel_data[index++];
    msblsb = (msb << 8) | lsb;
    report.accel_x = ((int16_t)msblsb >> 4); /* Data in X axis */

    lsb = (uint16_t)accel_data[index++];
    uint8_t status_y = (lsb & BMI055_NEW_DATA_MASK);
    msb = (uint16_t)accel_data[index++];
    msblsb = (msb << 8) | lsb;
    report.accel_y = ((int16_t)msblsb >> 4); /* Data in Y axis */

    lsb = (uint16_t)accel_data[index++];
    uint8_t status_z = (lsb & BMI055_NEW_DATA_MASK);
    msb = (uint16_t)accel_data[index++];
    msblsb = (msb << 8) | lsb;
    report.accel_z = ((int16_t)msblsb >> 4); /* Data in Z axis */

    // Byte
    report.temp = accel_data[index];

    // Checking the status of new data
    if ((!status_x) || (!status_y) || (!status_z)) {
        perf_end(_sample_perf);
        perf_count(_duplicates);
        _got_duplicate = true;
        return;
    }


    _got_duplicate = false;

    if (report.accel_x == 0 &&
        report.accel_y == 0 &&
        report.accel_z == 0 &&
        report.temp == 0) {
        // all zero data - probably a SPI bus error
        perf_count(_bad_transfers);
        perf_end(_sample_perf);
        // note that we don't call reset() here as a reset()
        // costs 20ms with interrupts disabled. That means if
        // the bmi055 accel does go bad it would cause a FMU failure,
        // regardless of whether another sensor is available,
        return;
    }

    if (_register_wait != 0) {
        // we are waiting for some good transfers before using
        // the sensor again, but don't return any data yet
        _register_wait--;
        return;
    }

    // report the error count as the sum of the number of bad
    // transfers and bad register reads. This allows the higher
    // level code to decide if it should use this sensor based on
    // whether it has had failures
    const uint64_t error_count = perf_event_count(_bad_transfers) + perf_event_count(_bad_registers);
    _px4_accel.set_error_count(error_count);

    /*
     * Temperature is reported as Eight-bit 2’s complement sensor temperature value
     * with 0.5 °C/LSB sensitivity and an offset of 23.0 °C
     */
    _px4_accel.set_temperature((report.temp * 0.5f) + 23.0f);

    /*
     * 1) Scale raw value to SI units using scaling from datasheet.
     * 2) Subtract static offset (in SI units)
     * 3) Scale the statically calibrated values with a linear
     *    dynamically obtained factor
     *
     * Note: the static sensor offset is the number the sensor outputs
     *   at a nominally 'zero' input. Therefore the offset has to
     *   be subtracted.
     *
     */
    _px4_accel.update(timestamp_sample, report.accel_x, report.accel_y, report.accel_z);

    /* stop measuring */
    perf_end(_sample_perf);
}

void
BMI055_accel::print_info()
{
    perf_print_counter(_sample_perf);
    perf_print_counter(_bad_transfers);
    perf_print_counter(_bad_registers);
    perf_print_counter(_duplicates);

    ::printf("checked_next: %u\n", _checked_next);

    for (uint8_t i = 0; i < BMI055_ACCEL_NUM_CHECKED_REGISTERS; i++) {
        uint8_t v = read_reg(_checked_registers[i]);

        if (v != _checked_values[i]) {
            ::printf("reg %02x:%02x should be %02x\n",
                 (unsigned)_checked_registers[i],
                 (unsigned)v,
                 (unsigned)_checked_values[i]);
        }

        if (v != _checked_bad[i]) {
            ::printf("reg %02x:%02x was bad %02x\n",
                 (unsigned)_checked_registers[i],
                 (unsigned)v,
                 (unsigned)_checked_bad[i]);
        }
    }

    _px4_accel.print_status();
}

void
BMI055_accel::print_registers()
{
    uint8_t index = 0;
    printf("BMI055 accel registers\n");

    uint8_t reg = _checked_registers[index++];
    uint8_t v = read_reg(reg);
    printf("Accel Chip Id: %02x:%02x ", (unsigned)reg, (unsigned)v);
    printf("\n");

    reg = _checked_registers[index++];
    v = read_reg(reg);
    printf("Accel Bw: %02x:%02x ", (unsigned)reg, (unsigned)v);
    printf("\n");

    reg = _checked_registers[index++];
    v = read_reg(reg);
    printf("Accel Range: %02x:%02x ", (unsigned)reg, (unsigned)v);
    printf("\n");

    reg = _checked_registers[index++];
    v = read_reg(reg);
    printf("Accel Int-en-1: %02x:%02x ", (unsigned)reg, (unsigned)v);
    printf("\n");

    reg = _checked_registers[index++];
    v = read_reg(reg);
    printf("Accel Int-Map-1: %02x:%02x ", (unsigned)reg, (unsigned)v);

    printf("\n");
}