LibrePilot/flight/pios/common/pios_adxl345.c

/**
 ******************************************************************************
 * @addtogroup PIOS PIOS Core hardware abstraction layer
 * @{
 * @addtogroup PIOS_ADXL345 ADXL345 Functions
 * @brief Deals with the hardware interface to the BMA180 3-axis accelerometer
 * @{
 *
 * @file       pios_adxl345.h
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2012.
 * @brief      PiOS ADXL345 digital accelerometer driver.
 * @see        The GNU Public License (GPL) Version 3
 *
 *****************************************************************************/
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include "pios.h"

#ifdef PIOS_INCLUDE_ADXL345

enum pios_adxl345_dev_magic {
    PIOS_ADXL345_DEV_MAGIC = 0xcb55aa55,
};

struct adxl345_dev {
    uint32_t spi_id;
    uint32_t slave_num;
    enum pios_adxl345_dev_magic magic;
};

// ! Global structure for this device device
static struct adxl345_dev *dev;

// ! Private functions
static struct adxl345_dev *PIOS_ADXL345_alloc(void);
static int32_t PIOS_ADXL345_Validate(struct adxl345_dev *dev);
static int32_t PIOS_ADXL345_ClaimBus();
static int32_t PIOS_ADXL345_ReleaseBus();
static int32_t PIOS_ADXL345_FifoDepth(uint8_t depth);

/**
 * @brief Allocate a new device
 */
static struct adxl345_dev *PIOS_ADXL345_alloc(void)
{
    struct adxl345_dev *adxl345_dev;

    adxl345_dev = (struct adxl345_dev *)pios_malloc(sizeof(*adxl345_dev));
    if (!adxl345_dev) {
        return NULL;
    }

    adxl345_dev->magic = PIOS_ADXL345_DEV_MAGIC;
    return adxl345_dev;
}

/**
 * @brief Validate the handle to the spi device
 * @returns 0 for valid device or -1 otherwise
 */
static int32_t PIOS_ADXL345_Validate(struct adxl345_dev *vdev)
{
    if (vdev == NULL) {
        return -1;
    }
    if (vdev->magic != PIOS_ADXL345_DEV_MAGIC) {
        return -2;
    }
    if (vdev->spi_id == 0) {
        return -3;
    }
    return 0;
}

/**
 * @brief Claim the SPI bus for the accel communications and select this chip
 * @return 0 for succesful claiming of bus or -1 otherwise
 */
static int32_t PIOS_ADXL345_ClaimBus()
{
    if (PIOS_ADXL345_Validate(dev) != 0) {
        return -1;
    }

    if (PIOS_SPI_ClaimBus(dev->spi_id) != 0) {
        return -2;
    }

    PIOS_SPI_RC_PinSet(dev->spi_id, dev->slave_num, 0);

    return 0;
}

/**
 * @brief Release the SPI bus for the accel communications and end the transaction
 * @return 0 if success or <0 for failure
 */
static int32_t PIOS_ADXL345_ReleaseBus()
{
    if (PIOS_ADXL345_Validate(dev) != 0) {
        return -1;
    }

    PIOS_SPI_RC_PinSet(dev->spi_id, dev->slave_num, 1);

    if (PIOS_SPI_ReleaseBus(dev->spi_id) != 0) {
        return -2;
    }

    return 0;
}

/**
 * @brief Select the sampling rate of the chip
 *
 * This also puts it into high power mode
 */
int32_t PIOS_ADXL345_SelectRate(uint8_t rate)
{
    if (PIOS_ADXL345_Validate(dev) != 0) {
        return -1;
    }

    if (PIOS_ADXL345_ClaimBus() != 0) {
        return -2;
    }

    uint8_t out[2] = { ADXL_RATE_ADDR, rate & 0x0F };
    if (PIOS_SPI_TransferBlock(dev->spi_id, out, NULL, sizeof(out), NULL) < 0) {
        PIOS_ADXL345_ReleaseBus();
        return -3;
    }

    PIOS_ADXL345_ReleaseBus();

    return 0;
}

/**
 * @brief Set the range of the accelerometer and set the data to be right justified
 * with sign extension.  Also keep device in 4 wire mode.
 */
int32_t PIOS_ADXL345_SetRange(uint8_t range)
{
    if (PIOS_ADXL345_Validate(dev) != 0) {
        return -1;
    }

    if (PIOS_ADXL345_ClaimBus() != 0) {
        return -2;
    }

    uint8_t out[2] = { ADXL_FORMAT_ADDR, (range & 0x03) | ADXL_FULL_RES | ADXL_4WIRE };
    if (PIOS_SPI_TransferBlock(dev->spi_id, out, NULL, sizeof(out), NULL) < 0) {
        PIOS_ADXL345_ReleaseBus();
        return -3;
    }

    PIOS_ADXL345_ReleaseBus();

    return 0;
}

/**
 * @brief Set the fifo depth that triggers an interrupt.  This will be matched to the oversampling
 */
static int32_t PIOS_ADXL345_FifoDepth(uint8_t depth)
{
    if (PIOS_ADXL345_Validate(dev) != 0) {
        return -1;
    }

    if (PIOS_ADXL345_ClaimBus() != 0) {
        return -2;
    }

    uint8_t out[2] = { ADXL_FIFO_ADDR, (depth & 0x1f) | ADXL_FIFO_STREAM };
    if (PIOS_SPI_TransferBlock(dev->spi_id, out, NULL, sizeof(out), NULL) < 0) {
        PIOS_ADXL345_ReleaseBus();
        return -3;
    }

    PIOS_ADXL345_ReleaseBus();

    return 0;
}

/**
 * @brief Enable measuring.  This also disables the activity sensors (tap or free fall)
 */
static int32_t PIOS_ADXL345_SetMeasure(__attribute__((unused)) uint8_t enable)
{
    if (PIOS_ADXL345_Validate(dev) != 0) {
        return -1;
    }

    if (PIOS_ADXL345_ClaimBus() != 0) {
        return -2;
    }

    uint8_t out[2] = { ADXL_POWER_ADDR, ADXL_MEAURE };
    if (PIOS_SPI_TransferBlock(dev->spi_id, out, NULL, sizeof(out), NULL) < 0) {
        PIOS_ADXL345_ReleaseBus();
        return -3;
    }

    PIOS_ADXL345_ReleaseBus();

    return 0;
}

/**
 * @brief Initialize with good default settings
 */
int32_t PIOS_ADXL345_Init(uint32_t spi_id, uint32_t slave_num)
{
    dev = PIOS_ADXL345_alloc();
    if (dev == NULL) {
        return -1;
    }

    dev->spi_id    = spi_id;
    dev->slave_num = slave_num;

    PIOS_ADXL345_ReleaseBus();
    PIOS_ADXL345_SelectRate(ADXL_RATE_1600);
    PIOS_ADXL345_SetRange(ADXL_RANGE_8G);
    PIOS_ADXL345_FifoDepth(16);
    PIOS_ADXL345_SetMeasure(1);

    return 0;
}

/**
 * @brief Return number of entries in the fifo
 */
int32_t PIOS_ADXL345_Test()
{
    if (PIOS_ADXL345_Validate(dev) != 0) {
        return -1;
    }

    if (PIOS_ADXL345_ClaimBus() != 0) {
        return -2;
    }

    uint8_t buf[2] = { 0, 0 };
    uint8_t rec[2] = { 0, 0 };
    buf[0] = ADXL_WHOAMI | ADXL_READ_BIT;

    if (PIOS_SPI_TransferBlock(dev->spi_id, &buf[0], &rec[0], sizeof(buf), NULL) < 0) {
        PIOS_ADXL345_ReleaseBus();
        return -3;
    }

    PIOS_ADXL345_ReleaseBus();

    return (rec[1] == ADXL_DEVICE_ID) ? 0 : -4;
}

/**
 * @brief Return number of entries in the fifo
 */
int32_t PIOS_ADXL345_FifoElements()
{
    if (PIOS_ADXL345_Validate(dev) != 0) {
        return -1;
    }

    if (PIOS_ADXL345_ClaimBus() != 0) {
        return -2;
    }

    uint8_t buf[2] = { 0, 0 };
    uint8_t rec[2] = { 0, 0 };
    buf[0] = ADXL_FIFOSTATUS_ADDR | ADXL_READ_BIT; // Read fifo status

    if (PIOS_SPI_TransferBlock(dev->spi_id, &buf[0], &rec[0], sizeof(buf), NULL) < 0) {
        PIOS_ADXL345_ReleaseBus();
        return -3;
    }

    PIOS_ADXL345_ReleaseBus();

    return rec[1] & 0x3f;
}


/**
 * @brief Read a single set of values from the x y z channels
 * @returns The number of samples remaining in the fifo
 */
uint8_t PIOS_ADXL345_Read(struct pios_adxl345_data *data)
{
    if (PIOS_ADXL345_Validate(dev) != 0) {
        return -1;
    }

    if (PIOS_ADXL345_ClaimBus() != 0) {
        return -2;
    }
    // To save memory use same buffer for in and out but offset by
    // a byte
    uint8_t buf[10] = { 0 };
    uint8_t *rec    = buf + 1;
    buf[0] = ADXL_X0_ADDR | ADXL_MULTI_BIT | ADXL_READ_BIT; // Multibyte read starting at X0
    if (PIOS_SPI_TransferBlock(dev->spi_id, &buf[0], &rec[0], 9, NULL) < 0) {
        PIOS_ADXL345_ReleaseBus();
        return -3;
    }

    PIOS_ADXL345_ReleaseBus();

    data->x = rec[1] + (rec[2] << 8);
    data->y = rec[3] + (rec[4] << 8);
    data->z = rec[5] + (rec[6] << 8);

    return rec[8] & 0x7F; // return number of remaining entries
}

/**
 * @brief Read a single set of values from the x y z channels
 * @returns 0 if successful
 */

int8_t PIOS_ADXL345_ReadAndAccumulateSamples(struct pios_adxl345_data *data, uint8_t samples)
{
    if (PIOS_ADXL345_Validate(dev) != 0) {
        return -1;
    }

    if (PIOS_ADXL345_ClaimBus() != 0) {
        return -2;
    }
    data->x = 0;
    data->y = 0;
    data->z = 0;
    // To save memory use same buffer for in and out but offset by
    // a byte
#ifdef PIOS_INCLUDE_INSTRUMENTATION
    PIOS_Instrumentation_TimeStart(counterUpd);
#endif
    for (uint8_t i = 0; i < samples; i++) {
        uint8_t buf[7] = { 0 };
        uint8_t *rec   = &buf[1];
        PIOS_SPI_RC_PinSet(dev->spi_id, dev->slave_num, 0);
        buf[0] = ADXL_X0_ADDR | ADXL_MULTI_BIT | ADXL_READ_BIT; // Multibyte read starting at X0
        if (PIOS_SPI_TransferBlock(dev->spi_id, &buf[0], &rec[0], 7, NULL) < 0) {
            PIOS_ADXL345_ReleaseBus();
            return -3;
        }
        PIOS_SPI_RC_PinSet(dev->spi_id, dev->slave_num, 1);
        data->x += rec[1] + (rec[2] << 8);
        data->y += rec[3] + (rec[4] << 8);
        data->z += rec[5] + (rec[6] << 8);
    }
    uint8_t r = PIOS_SPI_TransferByte(dev->spi_id, ADXL_FIFOSTATUS_ADDR | ADXL_READ_BIT);
#ifdef PIOS_INCLUDE_INSTRUMENTATION
    PIOS_Instrumentation_TimeEnd(counterUpd);
#endif
    PIOS_ADXL345_ReleaseBus();
    return r & 0x7F; // return number of remaining entries
}
#endif /* PIOS_INCLUDE_ADXL345 */