LibrePilot/flight/pios/common/pios_bma180.c

/**
 ******************************************************************************
 * @addtogroup PIOS PIOS Core hardware abstraction layer
 * @{
 * @addtogroup PIOS_BMA180 BMA180 Functions
 * @brief Deals with the hardware interface to the BMA180 3-axis accelerometer
 * @{
 *
 * @file       pios_bma180.h
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2012.
 * @brief      PiOS BMA180 digital accelerometer driver.
 *                 - Driver for the BMA180 digital accelerometer on the SPI bus.
 * @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_BMA180

#include "fifo_buffer.h"

enum pios_bma180_dev_magic {
    PIOS_BMA180_DEV_MAGIC = 0xcbb93755,
};

#define PIOS_BMA180_MAX_DOWNSAMPLE 10
struct bma180_dev {
    uint32_t spi_id;
    uint32_t slave_num;
    int16_t  buffer[PIOS_BMA180_MAX_DOWNSAMPLE * sizeof(struct pios_bma180_data)];
    t_fifo_buffer         fifo;
    const struct pios_bma180_cfg *cfg;
    enum bma180_bandwidth bandwidth;
    enum bma180_range     range;
    enum pios_bma180_dev_magic magic;
};

// ! Global structure for this device device
static struct bma180_dev *dev;

// ! Private functions
static struct bma180_dev *PIOS_BMA180_alloc(void);
static int32_t PIOS_BMA180_Validate(struct bma180_dev *dev);
static int32_t PIOS_BMA180_GetReg(uint8_t reg);
static int32_t PIOS_BMA180_SetReg(uint8_t reg, uint8_t data);
static int32_t PIOS_BMA180_SelectBW(enum bma180_bandwidth bw);
static int32_t PIOS_BMA180_SetRange(enum bma180_range range);
static int32_t PIOS_BMA180_Config();
static int32_t PIOS_BMA180_EnableIrq();

#define GRAV 9.81f

/**
 * @brief Allocate a new device
 */
static struct bma180_dev *PIOS_BMA180_alloc(void)
{
    struct bma180_dev *bma180_dev;

    bma180_dev = (struct bma180_dev *)pios_malloc(sizeof(*bma180_dev));
    if (!bma180_dev) {
        return NULL;
    }

    fifoBuf_init(&bma180_dev->fifo, (uint8_t *)bma180_dev->buffer, sizeof(bma180_dev->buffer));

    bma180_dev->magic = PIOS_BMA180_DEV_MAGIC;
    return bma180_dev;
}

/**
 * @brief Validate the handle to the spi device
 * @returns 0 for valid device or -1 otherwise
 */
static int32_t PIOS_BMA180_Validate(struct bma180_dev *vdev)
{
    if (vdev == NULL) {
        return -1;
    }
    if (vdev->magic != PIOS_BMA180_DEV_MAGIC) {
        return -2;
    }
    if (vdev->spi_id == 0) {
        return -3;
    }
    return 0;
}

/**
 * @brief Initialize with good default settings
 * @returns 0 for success, -1 for failure
 */
int32_t PIOS_BMA180_Init(uint32_t spi_id, uint32_t slave_num, const struct pios_bma180_cfg *cfg)
{
    dev = PIOS_BMA180_alloc();
    if (dev == NULL) {
        return -1;
    }

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

    if (PIOS_BMA180_Config() < 0) {
        return -1;
    }
    PIOS_DELAY_WaituS(50);

    PIOS_EXTI_Init(dev->cfg->exti_cfg);

    while (PIOS_BMA180_EnableIrq() != 0) {
        ;
    }

    return 0;
}

/**
 * @brief Claim the SPI bus for the accel communications and select this chip
 * @return 0 if successful, -1 if unable to claim bus
 */
int32_t PIOS_BMA180_ClaimBus()
{
    if (PIOS_BMA180_Validate(dev) != 0) {
        return -1;
    }

    if (PIOS_SPI_ClaimBus(dev->spi_id) != 0) {
        return -1;
    }

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

    return 0;
}

/**
 * @brief Claim the SPI bus for the accel communications and select this chip. Call from an ISR.
 * @param woken[in,out] If non-NULL, will be set to true if woken was false and a higher priority
 *                      task has is now eligible to run, else unchanged
 * @return 0 if successful, -1 if unable to claim bus
 */
int32_t PIOS_BMA180_ClaimBusISR(bool *woken)
{
    if (PIOS_BMA180_Validate(dev) != 0) {
        return -1;
    }

    if (PIOS_SPI_ClaimBusISR(dev->spi_id, woken) != 0) {
        return -1;
    }

    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 successful
 */
int32_t PIOS_BMA180_ReleaseBus()
{
    if (PIOS_BMA180_Validate(dev) != 0) {
        return -1;
    }
    PIOS_SPI_RC_PinSet(dev->spi_id, dev->slave_num, 1);

    return PIOS_SPI_ReleaseBus(dev->spi_id);
}

/**
 * @brief Release the SPI bus for the accel communications and end the transaction. Call from an ISR
 * @param woken[in,out] If non-NULL, will be set to true if woken was false and a higher priority
 *                      task has is now eligible to run, else unchanged
 * @return 0 if successful
 */
int32_t PIOS_BMA180_ReleaseBusISR(bool *woken)
{
    if (PIOS_BMA180_Validate(dev) != 0) {
        return -1;
    }

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

    return PIOS_SPI_ReleaseBusISR(dev->spi_id, woken);
}

/**
 * @brief Read a register from BMA180
 * @returns The register value or -1 if failure to get bus
 * @param reg[in] Register address to be read
 */
int32_t PIOS_BMA180_GetReg(uint8_t reg)
{
    if (PIOS_BMA180_Validate(dev) != 0) {
        return -1;
    }

    uint8_t data;

    if (PIOS_BMA180_ClaimBus() != 0) {
        return -1;
    }

    PIOS_SPI_TransferByte(dev->spi_id, (0x80 | reg)); // request byte
    data = PIOS_SPI_TransferByte(dev->spi_id, 0); // receive response

    PIOS_BMA180_ReleaseBus();
    return data;
}

/**
 * @brief Write a BMA180 register.  EEPROM must be unlocked before calling this function.
 * @return none
 * @param reg[in] address of register to be written
 * @param data[in] data that is to be written to register
 */
int32_t PIOS_BMA180_SetReg(uint8_t reg, uint8_t data)
{
    if (PIOS_BMA180_ClaimBus() != 0) {
        return -1;
    }

    PIOS_SPI_TransferByte(dev->spi_id, 0x7f & reg);
    PIOS_SPI_TransferByte(dev->spi_id, data);

    PIOS_BMA180_ReleaseBus();

    return 0;
}


static int32_t PIOS_BMA180_EnableEeprom()
{
    // Enable EEPROM writing
    int32_t byte = PIOS_BMA180_GetReg(BMA_CTRREG0);

    if (byte < 0) {
        return -1;
    }
    byte |= 0x10; // Set bit 4
    if (PIOS_BMA180_SetReg(BMA_CTRREG0, (uint8_t)byte) < 0) { // Have to set ee_w to
        return -1;
    }
    return 0;
}

static int32_t PIOS_BMA180_DisableEeprom()
{
    // Enable EEPROM writing
    int32_t byte = PIOS_BMA180_GetReg(BMA_CTRREG0);

    if (byte < 0) {
        return -1;
    }
    byte |= 0x10; // Set bit 4
    if (PIOS_BMA180_SetReg(BMA_CTRREG0, (uint8_t)byte) < 0) { // Have to set ee_w to
        return -1;
    }
    return 0;
}

/**
 * @brief Set the default register settings
 * @return 0 if successful, -1 if not
 */
static int32_t PIOS_BMA180_Config()
{
    /*
       0x35 = 0x81  //smp-skip = 1 for less interrupts
       0x33 = 0x81  //shadow-dis = 1, update MSB and LSB synchronously
       0x27 = 0x01  //dis-i2c
       0x21 = 0x02  //new_data_int = 1
     */

    PIOS_DELAY_WaituS(20);

    if (PIOS_BMA180_Validate(dev) != 0) {
        return -1;
    }

    while (PIOS_BMA180_EnableEeprom() != 0) {
        ;
    }
    while (PIOS_BMA180_SetReg(BMA_RESET, BMA_RESET_CODE) != 0) {
        ;
    }
    while (PIOS_BMA180_SetReg(BMA_OFFSET_LSB1, 0x81) != 0) {
        ;
    }
    while (PIOS_BMA180_SetReg(BMA_GAIN_Y, 0x81) != 0) {
        ;
    }
    while (PIOS_BMA180_SetReg(BMA_CTRREG3, 0xFF) != 0) {
        ;
    }
    while (PIOS_BMA180_SelectBW(dev->cfg->bandwidth) != 0) {
        ;
    }
    while (PIOS_BMA180_SetRange(dev->cfg->range) != 0) {
        ;
    }
    while (PIOS_BMA180_DisableEeprom() != 0) {
        ;
    }

    return 0;
}

/**
 * @brief Select the bandwidth the digital filter pass allows.
 * @return 0 if successful, -1 if not
 * @param rate[in] Bandwidth setting to be used
 *
 * EEPROM must be write-enabled before calling this function.
 */
static int32_t PIOS_BMA180_SelectBW(enum bma180_bandwidth bw)
{
    if (PIOS_BMA180_Validate(dev) != 0) {
        return -1;
    }

    dev->bandwidth = bw;

    uint8_t reg;
    reg = PIOS_BMA180_GetReg(BMA_BW_ADDR);
    reg = (reg & ~BMA_BW_MASK) | ((bw << BMA_BW_SHIFT) & BMA_BW_MASK);
    return PIOS_BMA180_SetReg(BMA_BW_ADDR, reg);
}

/**
 * @brief Select the full scale acceleration range.
 * @return 0 if successful, -1 if not
 * @param rate[in] Range setting to be used
 *
 */
static int32_t PIOS_BMA180_SetRange(enum bma180_range new_range)
{
    if (PIOS_BMA180_Validate(dev) != 0) {
        return -1;
    }

    uint8_t reg;

    dev->range = new_range;
    reg = PIOS_BMA180_GetReg(BMA_RANGE_ADDR);
    reg = (reg & ~BMA_RANGE_MASK) | ((dev->range << BMA_RANGE_SHIFT) & BMA_RANGE_MASK);
    return PIOS_BMA180_SetReg(BMA_RANGE_ADDR, reg);
}

static int32_t PIOS_BMA180_EnableIrq()
{
    if (PIOS_BMA180_EnableEeprom() < 0) {
        return -1;
    }

    if (PIOS_BMA180_SetReg(BMA_CTRREG3, BMA_NEW_DAT_INT) < 0) {
        return -1;
    }

    if (PIOS_BMA180_DisableEeprom() < 0) {
        return -1;
    }

    return 0;
}

/**
 * @brief Read a single set of values from the x y z channels
 * @param[out] data Int16 array of (x,y,z) sensor values
 * @returns 0 if successful
 * @retval -1 unable to claim bus
 * @retval -2 unable to transfer data
 */
int32_t PIOS_BMA180_ReadAccels(struct pios_bma180_data *data)
{
    // To save memory use same buffer for in and out but offset by
    // a byte
    uint8_t buf[7] = { BMA_X_LSB_ADDR | 0x80, 0, 0, 0, 0, 0 };
    uint8_t rec[7] = { 0, 0, 0, 0, 0, 0 };

    if (PIOS_BMA180_ClaimBus() != 0) {
        return -1;
    }
    if (PIOS_SPI_TransferBlock(dev->spi_id, &buf[0], &rec[0], 7, NULL) != 0) {
        return -2;
    }
    PIOS_BMA180_ReleaseBus();

    // |    MSB        |   LSB       | 0 | new_data |
    data->x  = ((rec[2] << 8) | rec[1]);
    data->y  = ((rec[4] << 8) | rec[3]);
    data->z  = ((rec[6] << 8) | rec[5]);
    data->x /= 4;
    data->y /= 4;
    data->z /= 4;

    return 0; // return number of remaining entries
}

/**
 * @brief Returns the scale the BMA180 chip is using
 * @return Scale (m / s^2) / LSB
 */
float PIOS_BMA180_GetScale()
{
    if (PIOS_BMA180_Validate(dev) != 0) {
        return -1;
    }

    switch (dev->cfg->range) {
    case BMA_RANGE_1G:
        return GRAV / 8192.0f;

    case BMA_RANGE_1_5G:
        return GRAV / 5460.0f;

    case BMA_RANGE_2G:
        return GRAV / 4096.0f;

    case BMA_RANGE_3G:
        return GRAV / 2730.0f;

    case BMA_RANGE_4G:
        return GRAV / 2048.0f;

    case BMA_RANGE_8G:
        return GRAV / 1024.0f;

    case BMA_RANGE_16G:
        return GRAV / 512.0f;
    }
    return 0;
}

/**
 * @brief Get data from fifo
 * @param [out] buffer pointer to a @ref pios_bma180_data structure to receive data
 * @return 0 for success, -1 for failure (no data available)
 */
int32_t PIOS_BMA180_ReadFifo(struct pios_bma180_data *buffer)
{
    if (PIOS_BMA180_Validate(dev) != 0) {
        return -1;
    }

    if (fifoBuf_getUsed(&dev->fifo) < sizeof(*buffer)) {
        return -1;
    }

    fifoBuf_getData(&dev->fifo, (uint8_t *)buffer, sizeof(*buffer));

    return 0;
}


/**
 * @brief Test SPI and chip functionality by reading chip ID register
 * @return 0 if success, -1 if failure.
 *
 */
int32_t PIOS_BMA180_Test()
{
    // Read chip ID then version ID
    uint8_t buf[3] = { 0x80 | BMA_CHIPID_ADDR, 0, 0 };
    uint8_t rec[3] = { 0, 0, 0 };
    int32_t retval;

    if (PIOS_BMA180_ClaimBus() != 0) {
        return -1;
    }
    retval = PIOS_SPI_TransferBlock(dev->spi_id, &buf[0], &rec[0], sizeof(buf), NULL);
    PIOS_BMA180_ReleaseBus();

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

    struct pios_bma180_data data;
    if (PIOS_BMA180_ReadAccels(&data) != 0) {
        return -3;
    }

    if (rec[1] != 0x3) {
        return -4;
    }

    if (rec[2] < 0x12) {
        return -5;
    }

    return 0;
}

/**
 * @brief EXTI IRQ Handler.  Read data from the BMA180 FIFO and push onto a local fifo.
 * @return a boolean to the EXTI IRQ Handler wrapper indicating if a
 *         higher priority task is now eligible to run
 */
int32_t bma180_irqs = 0;
bool PIOS_BMA180_IRQHandler(void)
{
    bool woken = false;
    static const uint8_t pios_bma180_req_buf[7] = { BMA_X_LSB_ADDR | 0x80, 0, 0, 0, 0, 0 };
    uint8_t pios_bma180_dmabuf[8];

    bma180_irqs++;

    // If we can't get the bus then just move on for efficiency
    if (PIOS_BMA180_ClaimBusISR(&woken) != 0) {
        return woken; // Something else is using bus, miss this data
    }

    PIOS_SPI_TransferBlock(dev->spi_id, pios_bma180_req_buf, (uint8_t *)pios_bma180_dmabuf,
                           sizeof(pios_bma180_dmabuf), NULL);

    // TODO: Make this conversion depend on configuration scale
    struct pios_bma180_data data;

    // Don't release bus till data has copied
    PIOS_BMA180_ReleaseBusISR(&woken);

    // Must not return before releasing bus
    if (fifoBuf_getFree(&dev->fifo) < sizeof(data)) {
        return woken;
    }

    // Bottom two bits indicate new data and are constant zeros.  Don't right
    // shift because it drops sign bit
    data.x  = ((pios_bma180_dmabuf[2] << 8) | pios_bma180_dmabuf[1]);
    data.y  = ((pios_bma180_dmabuf[4] << 8) | pios_bma180_dmabuf[3]);
    data.z  = ((pios_bma180_dmabuf[6] << 8) | pios_bma180_dmabuf[5]);
    data.x /= 4;
    data.y /= 4;
    data.z /= 4;
    data.temperature = pios_bma180_dmabuf[7];

    fifoBuf_putData(&dev->fifo, (uint8_t *)&data, sizeof(data));

    return woken;
}

#endif /* PIOS_INCLUDE_BMA180 */

/**
 * @}
 * @}
 */