lsm303agr.c

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/*
    ChibiOS - Copyright (C) 2016..2019 Rocco Marco Guglielmi
 
    This file is part of ChibiOS.
 
    ChibiOS 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.
 
    ChibiOS 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, see <http://www.gnu.org/licenses/>.
  
*/
 
/**
 * @file    lsm303agr.c
 * @brief   LSM303AGR MEMS interface module code.
 *
 * @addtogroup LSM303AGR
 * @ingroup EX_ST
 * @{
 */
 
#include "hal.h"
#include "lsm303agr.h"
 
/*===========================================================================*/
/* Driver local definitions.                                                 */
/*===========================================================================*/
 
/*===========================================================================*/
/* Driver exported variables.                                                */
/*===========================================================================*/
 
/*===========================================================================*/
/* Driver local variables and types.                                         */
/*===========================================================================*/
 
/**
 * @brief  Accelerometer and Compass Slave Address.
 */
typedef enum {
  LSM303AGR_SAD_ACC = 0x19,        /**< SAD for accelerometer.             */
  LSM303AGR_SAD_COMP = 0x1E        /**< SAD for compass.                   */
} lsm303agr_sad_t;
 
/*===========================================================================*/
/* Driver local functions.                                                   */
/*===========================================================================*/
 
/**
 * @brief   Reads registers value using I2C.
 * @pre     The I2C interface must be initialized and the driver started.
 * @note    IF_ADD_INC bit must be 1 in CTRL_REG8.
 *
 * @param[in] i2cp       pointer to the I2C interface.
 * @param[in] sad        slave address without R bit.
 * @param[in] reg        first sub-register address.
 * @param[in] rxbuf      receiving buffer.
 * @param[in] n          size of rxbuf.
 * @return               the operation status.
 */
static msg_t lsm303agrI2CReadRegister(I2CDriver *i2cp, lsm303agr_sad_t sad,
                                      uint8_t reg, uint8_t *rxbuf, size_t n) {
 
  uint8_t txbuf = reg | LSM303AGR_MS;
  return i2cMasterTransmitTimeout(i2cp, sad, &txbuf, 1, rxbuf, n,
                                  TIME_INFINITE);
}
 
/**
 * @brief   Writes a value into a register using I2C.
 * @pre     The I2C interface must be initialized and the driver started.
 *
 * @param[in] i2cp      pointer to the I2C interface.
 * @param[in] sad       slave address without R bit.
 * @param[in] txbuf     buffer containing sub-address value in first position
 *                      and values to write.
 * @param[in] n         size of txbuf less one (not considering the first
 *                      element).
 * @return              the operation status.
 */
static msg_t lsm303agrI2CWriteRegister(I2CDriver *i2cp, lsm303agr_sad_t sad,
                                       uint8_t *txbuf, size_t n) {
  if (n != 1)
    *txbuf |= LSM303AGR_MS;
  return i2cMasterTransmitTimeout(i2cp, sad, txbuf, n + 1, NULL, 0,
                                  TIME_INFINITE);
}
 
/**
 * @brief   Return the number of axes of the BaseAccelerometer.
 *
 * @param[in] ip        pointer to @p BaseAccelerometer interface.
 *
 * @return              the number of axes.
 */
static size_t acc_get_axes_number(void *ip) {
  (void)ip;
 
  return LSM303AGR_ACC_NUMBER_OF_AXES;
}
 
/**
 * @brief   Retrieves raw data from the BaseAccelerometer.
 * @note    This data is retrieved from MEMS register without any algebraical
 *          manipulation.
 * @note    The axes array must be at least the same size of the
 *          BaseAccelerometer axes number.
 *
 * @param[in] ip        pointer to @p BaseAccelerometer interface.
 * @param[out] axes     a buffer which would be filled with raw data.
 *
 * @return              The operation status.
 * @retval MSG_OK       if the function succeeded.
 * @retval MSG_RESET    if one or more I2C errors occurred, the errors can
 *                      be retrieved using @p i2cGetErrors().
 * @retval MSG_TIMEOUT  if a timeout occurred before operation end.
 */
static msg_t acc_read_raw(void *ip, int32_t axes[]) {
  LSM303AGRDriver* devp;
  uint8_t buff [LSM303AGR_ACC_NUMBER_OF_AXES * 2], i;
  int16_t tmp;
  msg_t msg;
 
  osalDbgCheck((ip != NULL) && (axes != NULL));
 
  /* Getting parent instance pointer.*/
  devp = objGetInstance(LSM303AGRDriver*, (BaseAccelerometer*)ip);
 
  osalDbgAssert((devp->state == LSM303AGR_READY),
                "acc_read_raw(), invalid state");
  osalDbgAssert((devp->config->i2cp->state == I2C_READY),
                "acc_read_raw(), channel not ready");
 
#if LSM303AGR_SHARED_I2C
  i2cAcquireBus(devp->config->i2cp);
  i2cStart(devp->config->i2cp,
           devp->config->i2ccfg);
#endif /* LSM303AGR_SHARED_I2C */
 
  msg = lsm303agrI2CReadRegister(devp->config->i2cp, LSM303AGR_SAD_ACC,
                                  LSM303AGR_AD_OUT_X_L_A, buff,
                                  LSM303AGR_ACC_NUMBER_OF_AXES * 2);
 
#if LSM303AGR_SHARED_I2C
  i2cReleaseBus(devp->config->i2cp);
#endif /* LSM303AGR_SHARED_I2C */
 
  if(msg == MSG_OK)
    for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++) {
      tmp = buff[2 * i] + (buff[2 * i + 1] << 8);
      axes[i] = (int32_t)tmp;
    }
  return msg;
}
 
/**
 * @brief   Retrieves cooked data from the BaseAccelerometer.
 * @note    This data is manipulated according to the formula
 *          cooked = (raw * sensitivity) - bias.
 * @note    Final data is expressed as milli-G.
 * @note    The axes array must be at least the same size of the
 *          BaseAccelerometer axes number.
 *
 * @param[in] ip        pointer to @p BaseAccelerometer interface.
 * @param[out] axes     a buffer which would be filled with cooked data.
 *
 * @return              The operation status.
 * @retval MSG_OK       if the function succeeded.
 * @retval MSG_RESET    if one or more I2C errors occurred, the errors can
 *                      be retrieved using @p i2cGetErrors().
 * @retval MSG_TIMEOUT  if a timeout occurred before operation end.
 */
static msg_t acc_read_cooked(void *ip, float axes[]) {
  LSM303AGRDriver* devp;
  uint32_t i;
  int32_t raw[LSM303AGR_ACC_NUMBER_OF_AXES];
  msg_t msg;
 
  osalDbgCheck((ip != NULL) && (axes != NULL));
 
  /* Getting parent instance pointer.*/
  devp = objGetInstance(LSM303AGRDriver*, (BaseAccelerometer*)ip);
 
  osalDbgAssert((devp->state == LSM303AGR_READY),
                "acc_read_cooked(), invalid state");
 
  msg = acc_read_raw(ip, raw);
  for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++) {
    axes[i] = (raw[i] * devp->accsensitivity[i]) - devp->accbias[i];
  }
  return msg;
}
 
/**
 * @brief   Set bias values for the BaseAccelerometer.
 * @note    Bias must be expressed as milli-G.
 * @note    The bias buffer must be at least the same size of the
 *          BaseAccelerometer axes number.
 *
 * @param[in] ip        pointer to @p BaseAccelerometer interface.
 * @param[in] bp        a buffer which contains biases.
 *
 * @return              The operation status.
 * @retval MSG_OK       if the function succeeded.
 */
static msg_t acc_set_bias(void *ip, float *bp) {
  LSM303AGRDriver* devp;
  uint32_t i;
  msg_t msg = MSG_OK;
 
  osalDbgCheck((ip != NULL) && (bp != NULL));
 
  /* Getting parent instance pointer.*/
  devp = objGetInstance(LSM303AGRDriver*, (BaseAccelerometer*)ip);
 
  osalDbgAssert((devp->state == LSM303AGR_READY),
                "acc_set_bias(), invalid state");
 
  for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++) {
    devp->accbias[i] = bp[i];
  }
  return msg;
}
 
/**
 * @brief   Reset bias values for the BaseAccelerometer.
 * @note    Default biases value are obtained from device datasheet when
 *          available otherwise they are considered zero.
 *
 * @param[in] ip        pointer to @p BaseAccelerometer interface.
 *
 * @return              The operation status.
 * @retval MSG_OK       if the function succeeded.
 */
static msg_t acc_reset_bias(void *ip) {
  LSM303AGRDriver* devp;
  uint32_t i;
  msg_t msg = MSG_OK;
 
  osalDbgCheck(ip != NULL);
 
  /* Getting parent instance pointer.*/
  devp = objGetInstance(LSM303AGRDriver*, (BaseAccelerometer*)ip);
 
  osalDbgAssert((devp->state == LSM303AGR_READY),
                "acc_reset_bias(), invalid state");
 
  for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++)
    devp->accbias[i] = LSM303AGR_ACC_BIAS;
  return msg;
}
 
/**
 * @brief   Set sensitivity values for the BaseAccelerometer.
 * @note    Sensitivity must be expressed as milli-G/LSB.
 * @note    The sensitivity buffer must be at least the same size of the
 *          BaseAccelerometer axes number.
 *
 * @param[in] ip        pointer to @p BaseAccelerometer interface.
 * @param[in] sp        a buffer which contains sensitivities.
 *
 * @return              The operation status.
 * @retval MSG_OK       if the function succeeded.
 */
static msg_t acc_set_sensivity(void *ip, float *sp) {
  LSM303AGRDriver* devp;
  uint32_t i;
  msg_t msg = MSG_OK;
 
  /* Getting parent instance pointer.*/
  devp = objGetInstance(LSM303AGRDriver*, (BaseAccelerometer*)ip);
 
  osalDbgCheck((ip != NULL) && (sp != NULL));
 
  osalDbgAssert((devp->state == LSM303AGR_READY),
                "acc_set_sensivity(), invalid state");
 
  for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++) {
    devp->accsensitivity[i] = sp[i];
  }
  return msg;
}
 
/**
 * @brief   Reset sensitivity values for the BaseAccelerometer.
 * @note    Default sensitivities value are obtained from device datasheet.
 *
 * @param[in] ip        pointer to @p BaseAccelerometer interface.
 *
 * @return              The operation status.
 * @retval MSG_OK       if the function succeeded.
 * @retval MSG_RESET    otherwise.
 */
static msg_t acc_reset_sensivity(void *ip) {
  LSM303AGRDriver* devp;
  uint32_t i;
  msg_t msg = MSG_OK;
 
  osalDbgCheck(ip != NULL);
 
  /* Getting parent instance pointer.*/
  devp = objGetInstance(LSM303AGRDriver*, (BaseAccelerometer*)ip);
 
  osalDbgAssert((devp->state == LSM303AGR_READY),
                "acc_reset_sensivity(), invalid state");
 
  if(devp->config->accfullscale == LSM303AGR_ACC_FS_2G) {
    for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++) {
      devp->accsensitivity[i] = LSM303AGR_ACC_SENS_2G;
    }
  }
  else if(devp->config->accfullscale == LSM303AGR_ACC_FS_4G) {
    for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++) {
      devp->accsensitivity[i] = LSM303AGR_ACC_SENS_4G;
    }
  }
  else if(devp->config->accfullscale == LSM303AGR_ACC_FS_8G) {
    for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++) {
      devp->accsensitivity[i] = LSM303AGR_ACC_SENS_8G;
    }
  }
  else if(devp->config->accfullscale == LSM303AGR_ACC_FS_16G) {
    for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++) {
      devp->accsensitivity[i] = LSM303AGR_ACC_SENS_16G;
    }
  }
  else {
    osalDbgAssert(FALSE, "reset_sensivity(), accelerometer full scale issue");
    msg = MSG_RESET;
  }
  return msg;
}
 
/**
 * @brief   Changes the LSM303AGRDriver accelerometer fullscale value.
 * @note    This function also rescale sensitivities and biases based on
 *          previous and next fullscale value.
 * @note    A recalibration is highly suggested after calling this function.
 *
 * @param[in] devp      pointer to @p LSM303AGRDriver interface.
 * @param[in] fs        new fullscale value.
 *
 * @return              The operation status.
 * @retval MSG_OK       if the function succeeded.
 * @retval MSG_RESET    otherwise.
 */
static msg_t acc_set_full_scale(LSM303AGRDriver *devp,
                                lsm303agr_acc_fs_t fs) {
  float newfs, scale;
  uint8_t i, buff[2];
  msg_t msg;
 
  osalDbgCheck(devp != NULL);
 
  osalDbgAssert((devp->state == LSM303AGR_READY),
                "acc_set_full_scale(), invalid state");
  osalDbgAssert((devp->config->i2cp->state == I2C_READY),
                "acc_set_full_scale(), channel not ready");
 
  /* Computing new fullscale value.*/
  if(fs == LSM303AGR_ACC_FS_2G) {
    newfs = LSM303AGR_ACC_2G;
  }
  else if(fs == LSM303AGR_ACC_FS_4G) {
    newfs = LSM303AGR_ACC_4G;
  }
  else if(fs == LSM303AGR_ACC_FS_8G) {
    newfs = LSM303AGR_ACC_8G;
  }
  else if(fs == LSM303AGR_ACC_FS_16G) {
    newfs = LSM303AGR_ACC_16G;
  }
  else {
    msg = MSG_RESET;
    return msg;
  }
 
  if(newfs != devp->accfullscale) {
    /* Computing scale value.*/
    scale = newfs / devp->accfullscale;
    devp->accfullscale = newfs;
 
#if LSM303AGR_SHARED_I2C
    i2cAcquireBus(devp->config->i2cp);
    i2cStart(devp->config->i2cp,
             devp->config->i2ccfg);
#endif /* LSM303AGR_SHARED_I2C */
 
    /* Updating register.*/
    msg = lsm303agrI2CReadRegister(devp->config->i2cp,
                                   LSM303AGR_SAD_ACC,
                                   LSM303AGR_AD_CTRL_REG4_A,
                                   &buff[1], 1);
 
#if LSM303AGR_SHARED_I2C
        i2cReleaseBus(devp->config->i2cp);
#endif /* LSM303AGR_SHARED_I2C */
 
    if(msg != MSG_OK)
      return msg;
 
    buff[1] &= ~(LSM303AGR_CTRL_REG4_A_FS_MASK);
    buff[1] |= fs;
    buff[0] = LSM303AGR_AD_CTRL_REG4_A;
 
#if LSM303AGR_SHARED_I2C
    i2cAcquireBus(devp->config->i2cp);
    i2cStart(devp->config->i2cp, devp->config->i2ccfg);
#endif /* LSM303AGR_SHARED_I2C */
 
    msg = lsm303agrI2CWriteRegister(devp->config->i2cp,
                                    LSM303AGR_SAD_ACC, buff, 1);
 
#if LSM303AGR_SHARED_I2C
    i2cReleaseBus(devp->config->i2cp);
#endif /* LSM303AGR_SHARED_I2C */
 
    if(msg != MSG_OK)
      return msg;
 
    /* Scaling sensitivity and bias. Re-calibration is suggested anyway.*/
    for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++) {
      devp->accsensitivity[i] *= scale;
      devp->accbias[i] *= scale;
    }
  }
  return msg;
}
 
/**
 * @brief   Return the number of axes of the BaseCompass.
 *
 * @param[in] ip        pointer to @p BaseCompass interface
 *
 * @return              the number of axes.
 */
static size_t comp_get_axes_number(void *ip) {
 
  osalDbgCheck(ip != NULL);
  return LSM303AGR_COMP_NUMBER_OF_AXES;
}
 
/**
 * @brief   Retrieves raw data from the BaseCompass.
 * @note    This data is retrieved from MEMS register without any algebraical
 *          manipulation.
 * @note    The axes array must be at least the same size of the
 *          BaseCompass axes number.
 *
 * @param[in] ip        pointer to @p BaseCompass interface.
 * @param[out] axes     a buffer which would be filled with raw data.
 *
 * @return              The operation status.
 * @retval MSG_OK       if the function succeeded.
 * @retval MSG_RESET    if one or more I2C errors occurred, the errors can
 *                      be retrieved using @p i2cGetErrors().
 * @retval MSG_TIMEOUT  if a timeout occurred before operation end.
 */
static msg_t comp_read_raw(void *ip, int32_t axes[]) {
  LSM303AGRDriver* devp;
  uint8_t buff [LSM303AGR_COMP_NUMBER_OF_AXES * 2], i;
  int16_t tmp;
  msg_t msg;
 
  osalDbgCheck((ip != NULL) && (axes != NULL));
 
  /* Getting parent instance pointer.*/
  devp = objGetInstance(LSM303AGRDriver*, (BaseCompass*)ip);
 
  osalDbgAssert((devp->state == LSM303AGR_READY),
                "comp_read_raw(), invalid state");
  osalDbgAssert((devp->config->i2cp->state == I2C_READY),
                "comp_read_raw(), channel not ready");
 
#if LSM303AGR_SHARED_I2C
  i2cAcquireBus(devp->config->i2cp);
  i2cStart(devp->config->i2cp,
           devp->config->i2ccfg);
#endif /* LSM303AGR_SHARED_I2C */
  msg = lsm303agrI2CReadRegister(devp->config->i2cp, LSM303AGR_SAD_COMP,
                                  LSM303AGR_AD_OUTX_L_REG_M, buff,
                                  LSM303AGR_COMP_NUMBER_OF_AXES * 2);
 
#if LSM303AGR_SHARED_I2C
  i2cReleaseBus(devp->config->i2cp);
#endif /* LSM303AGR_SHARED_I2C */
 
  if(msg == MSG_OK)
    for(i = 0; i < LSM303AGR_COMP_NUMBER_OF_AXES; i++) {
      tmp = buff[2 * i] + (buff[2 * i + 1] << 8);
      axes[i] = (int32_t)tmp;
    }
  return msg;
}
 
/**
 * @brief   Retrieves cooked data from the BaseCompass.
 * @note    This data is manipulated according to the formula
 *          cooked = (raw * sensitivity) - bias.
 * @note    Final data is expressed as G.
 * @note    The axes array must be at least the same size of the
 *          BaseCompass axes number.
 *
 * @param[in] ip        pointer to @p BaseCompass interface.
 * @param[out] axes     a buffer which would be filled with cooked data.
 *
 * @return              The operation status.
 * @retval MSG_OK       if the function succeeded.
 * @retval MSG_RESET    if one or more I2C errors occurred, the errors can
 *                      be retrieved using @p i2cGetErrors().
 * @retval MSG_TIMEOUT  if a timeout occurred before operation end.
 */
static msg_t comp_read_cooked(void *ip, float axes[]) {
  LSM303AGRDriver* devp;
  uint32_t i;
  int32_t raw[LSM303AGR_COMP_NUMBER_OF_AXES];
  msg_t msg;
 
  osalDbgCheck((ip != NULL) && (axes != NULL));
 
 
  /* Getting parent instance pointer.*/
  devp = objGetInstance(LSM303AGRDriver*, (BaseCompass*)ip);
 
  osalDbgAssert((devp->state == LSM303AGR_READY),
                "comp_read_cooked(), invalid state");
 
  msg = comp_read_raw(ip, raw);
  for(i = 0; i < LSM303AGR_COMP_NUMBER_OF_AXES ; i++) {
    axes[i] = (raw[i] * devp->compsensitivity[i]) - devp->compbias[i];
  }
  return msg;
}
 
/**
 * @brief   Set bias values for the BaseCompass.
 * @note    Bias must be expressed as G.
 * @note    The bias buffer must be at least the same size of the
 *          BaseCompass axes number.
 *
 * @param[in] ip        pointer to @p BaseCompass interface.
 * @param[in] bp        a buffer which contains biases.
 *
 * @return              The operation status.
 * @retval MSG_OK       if the function succeeded.
 */
static msg_t comp_set_bias(void *ip, float *bp) {
  LSM303AGRDriver* devp;
  uint32_t i;
  msg_t msg = MSG_OK;
 
  osalDbgCheck((ip != NULL) && (bp != NULL));
 
  /* Getting parent instance pointer.*/
  devp = objGetInstance(LSM303AGRDriver*, (BaseCompass*)ip);
 
  osalDbgAssert((devp->state == LSM303AGR_READY),
                "comp_set_bias(), invalid state");
 
  for(i = 0; i < LSM303AGR_COMP_NUMBER_OF_AXES; i++) {
    devp->compbias[i] = bp[i];
  }
  return msg;
}
 
/**
 * @brief   Reset bias values for the BaseCompass.
 * @note    Default biases value are obtained from device datasheet when
 *          available otherwise they are considered zero.
 *
 * @param[in] ip        pointer to @p BaseCompass interface.
 *
 * @return              The operation status.
 * @retval MSG_OK       if the function succeeded.
 */
static msg_t comp_reset_bias(void *ip) {
  LSM303AGRDriver* devp;
  uint32_t i;
  msg_t msg = MSG_OK;
 
  osalDbgCheck(ip != NULL);
 
  /* Getting parent instance pointer.*/
  devp = objGetInstance(LSM303AGRDriver*, (BaseCompass*)ip);
 
  osalDbgAssert((devp->state == LSM303AGR_READY),
                "comp_reset_bias(), invalid state");
 
  for(i = 0; i < LSM303AGR_COMP_NUMBER_OF_AXES; i++)
    devp->compbias[i] = LSM303AGR_COMP_BIAS;
  return msg;
}
 
/**
 * @brief   Set sensitivity values for the BaseCompass.
 * @note    Sensitivity must be expressed as G/LSB.
 * @note    The sensitivity buffer must be at least the same size of the
 *          BaseCompass axes number.
 *
 * @param[in] ip        pointer to @p BaseCompass interface.
 * @param[in] sp        a buffer which contains sensitivities.
 *
 * @return              The operation status.
 * @retval MSG_OK       if the function succeeded.
 */
static msg_t comp_set_sensivity(void *ip, float *sp) {
  LSM303AGRDriver* devp;
  uint32_t i;
  msg_t msg = MSG_OK;
 
  /* Getting parent instance pointer.*/
  devp = objGetInstance(LSM303AGRDriver*, (BaseCompass*)ip);
 
  osalDbgCheck((ip != NULL) && (sp != NULL));
 
  osalDbgAssert((devp->state == LSM303AGR_READY),
                "comp_set_sensivity(), invalid state");
 
  for(i = 0; i < LSM303AGR_COMP_NUMBER_OF_AXES; i++) {
    devp->compsensitivity[i] = sp[i];
  }
  return msg;
}
 
/**
 * @brief   Reset sensitivity values for the BaseCompass.
 * @note    Default sensitivities value are obtained from device datasheet.
 *
 * @param[in] ip        pointer to @p BaseCompass interface.
 *
 * @return              The operation status.
 * @retval MSG_OK       if the function succeeded.
 * @retval MSG_RESET    otherwise.
 */
static msg_t comp_reset_sensivity(void *ip) {
  LSM303AGRDriver* devp;
  uint32_t i;
  msg_t msg = MSG_OK;
 
  osalDbgCheck(ip != NULL);
 
  /* Getting parent instance pointer.*/
  devp = objGetInstance(LSM303AGRDriver*, (BaseCompass*)ip);
 
  osalDbgAssert((devp->state == LSM303AGR_READY),
                "comp_reset_sensivity(), invalid state");
 
  for(i = 0; i < LSM303AGR_COMP_NUMBER_OF_AXES; i++)
    devp->compsensitivity[i] = LSM303AGR_COMP_SENS_50GA;
  
  return msg;
}
 
static const struct LSM303AGRVMT vmt_device = {
  (size_t)0,
  acc_set_full_scale
};
 
static const struct BaseAccelerometerVMT vmt_accelerometer = {
  sizeof(struct LSM303AGRVMT*),
  acc_get_axes_number, acc_read_raw, acc_read_cooked,
  acc_set_bias, acc_reset_bias, acc_set_sensivity, acc_reset_sensivity
};
 
static const struct BaseCompassVMT vmt_compass = {
  sizeof(struct LSM303AGRVMT*) + sizeof(BaseAccelerometer),
  comp_get_axes_number, comp_read_raw, comp_read_cooked,
  comp_set_bias, comp_reset_bias, comp_set_sensivity, comp_reset_sensivity
};
 
/*===========================================================================*/
/* Driver exported functions.                                                */
/*===========================================================================*/
 
/**
 * @brief   Initializes an instance.
 *
 * @param[out] devp     pointer to the @p LSM303AGRDriver object
 *
 * @init
 */
void lsm303agrObjectInit(LSM303AGRDriver *devp) {
  devp->vmt = &vmt_device;
  devp->acc_if.vmt = &vmt_accelerometer;
  devp->comp_if.vmt = &vmt_compass;
 
  devp->config = NULL;
 
  devp->accaxes = LSM303AGR_ACC_NUMBER_OF_AXES;
  devp->compaxes = LSM303AGR_COMP_NUMBER_OF_AXES;
 
  devp->state = LSM303AGR_STOP;
}
 
/**
 * @brief   Configures and activates LSM303AGR Complex Driver peripheral.
 *
 * @param[in] devp      pointer to the @p LSM303AGRDriver object
 * @param[in] config    pointer to the @p LSM303AGRConfig object
 *
 * @api
 */
void lsm303agrStart(LSM303AGRDriver *devp, const LSM303AGRConfig *config) {
  uint32_t i;
  uint8_t cr[6];
  osalDbgCheck((devp != NULL) && (config != NULL));
 
  osalDbgAssert((devp->state == LSM303AGR_STOP) ||
                (devp->state == LSM303AGR_READY),
                "lsm303agrStart(), invalid state");
 
  devp->config = config;
 
  /* Configuring Accelerometer subsystem.*/
 
  /* Multiple write starting address.*/
  cr[0] = LSM303AGR_AD_CTRL_REG1_A;
 
  /* Control register 1 configuration block.*/
  {
    cr[1] = LSM303AGR_ACC_AE_XYZ | devp->config->accoutdatarate;
#if LSM303AGR_USE_ADVANCED || defined(__DOXYGEN__)
    if(devp->config->accmode == LSM303AGR_ACC_MODE_LPOW)
      cr[1] |= LSM303AGR_CTRL_REG1_A_LPEN;
#endif
  }
 
  /* Control register 2 configuration block.*/
  {
    cr[2] = 0;
  }
 
  /* Control register 3 configuration block.*/
  {
    cr[3] = 0;
  }
 
  /* Control register 4 configuration block.*/
  {
    cr[4] = devp->config->accfullscale;
#if LSM303AGR_USE_ADVANCED || defined(__DOXYGEN__)
    cr[4] |= devp->config->accendianess |
             devp->config->accblockdataupdate;
    if(devp->config->accmode == LSM303AGR_ACC_MODE_HRES)
      cr[4] |= LSM303AGR_CTRL_REG4_A_HR;
#endif
  }
 
  /* Storing sensitivity according to user settings */
  if(devp->config->accfullscale == LSM303AGR_ACC_FS_2G) {
    devp->accfullscale = LSM303AGR_ACC_2G;
    for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++) {
      if(devp->config->accsensitivity == NULL)
        devp->accsensitivity[i] = LSM303AGR_ACC_SENS_2G;
      else
        devp->accsensitivity[i] = devp->config->accsensitivity[i];
    }
  }
  else if(devp->config->accfullscale == LSM303AGR_ACC_FS_4G) {
    devp->accfullscale = LSM303AGR_ACC_4G;
    for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++) {
      if(devp->config->accsensitivity == NULL)
        devp->accsensitivity[i] = LSM303AGR_ACC_SENS_4G;
      else
        devp->accsensitivity[i] = devp->config->accsensitivity[i];
    }
  }
  else if(devp->config->accfullscale == LSM303AGR_ACC_FS_8G) {
    devp->accfullscale = LSM303AGR_ACC_8G;
    for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++) {
      if(devp->config->accsensitivity == NULL)
        devp->accsensitivity[i] = LSM303AGR_ACC_SENS_8G;
      else
        devp->accsensitivity[i] = devp->config->accsensitivity[i];
    }
  }
  else if(devp->config->accfullscale == LSM303AGR_ACC_FS_16G) {
    devp->accfullscale = LSM303AGR_ACC_16G;
    for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++) {
      if(devp->config->accsensitivity == NULL)
        devp->accsensitivity[i] = LSM303AGR_ACC_SENS_16G;
      else
        devp->accsensitivity[i] = devp->config->accsensitivity[i];
    }
  }
  else
    osalDbgAssert(FALSE, "lsm303dlhcStart(), accelerometer full scale issue");
 
  /* Storing bias information */
  if(devp->config->accbias != NULL)
    for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++)
      devp->accbias[i] = devp->config->accbias[i];
  else
    for(i = 0; i < LSM303AGR_ACC_NUMBER_OF_AXES; i++)
      devp->accbias[i] = LSM303AGR_ACC_BIAS;
 
#if LSM303AGR_SHARED_I2C
  i2cAcquireBus((devp)->config->i2cp);
#endif /* LSM303AGR_SHARED_I2C */
  i2cStart((devp)->config->i2cp, (devp)->config->i2ccfg);
 
  lsm303agrI2CWriteRegister(devp->config->i2cp, LSM303AGR_SAD_ACC, cr, 4);
 
#if LSM303AGR_SHARED_I2C
  i2cReleaseBus((devp)->config->i2cp);
#endif /* LSM303AGR_SHARED_I2C */
  
  /* Configuring Compass subsystem */
  /* Multiple write starting address.*/
  cr[0] = LSM303AGR_AD_CFG_REG_A_M;
 
  /* Control register A configuration block.*/
  {
    cr[1] = devp->config->compoutputdatarate;
#if LSM303AGR_USE_ADVANCED || defined(__DOXYGEN__)
    cr[1] |= devp->config->compmode | devp->config->complp;
#endif
  }
 
  /* Control register B configuration block.*/
  {
    cr[2] = 0;
  }
 
  /* Control register C configuration block.*/
  {
    cr[3] = 0;
  }
 
#if LSM303AGR_SHARED_I2C
  i2cAcquireBus((devp)->config->i2cp);
  i2cStart((devp)->config->i2cp, (devp)->config->i2ccfg);
#endif /* LSM303AGR_SHARED_I2C */
 
  lsm303agrI2CWriteRegister(devp->config->i2cp, LSM303AGR_SAD_COMP,
                            cr, 3);
 
#if LSM303AGR_SHARED_I2C
  i2cReleaseBus((devp)->config->i2cp);
#endif /* LSM303AGR_SHARED_I2C */
 
  devp->compfullscale = LSM303AGR_COMP_50GA;
  for(i = 0; i < LSM303AGR_COMP_NUMBER_OF_AXES; i++) {
    if(devp->config->compsensitivity == NULL) {
      devp->compsensitivity[i] = LSM303AGR_COMP_SENS_50GA;
    }
    else {
      devp->compsensitivity[i] = devp->config->compsensitivity[i];
    }
  }
    
  /* This is the MEMS transient recovery time */
  osalThreadSleepMilliseconds(5);
 
  devp->state = LSM303AGR_READY;
}
 
/**
 * @brief   Deactivates the LSM303AGR Complex Driver peripheral.
 *
 * @param[in] devp       pointer to the @p LSM303AGRDriver object
 *
 * @api
 */
void lsm303agrStop(LSM303AGRDriver *devp) {
  uint8_t cr[2];
  osalDbgCheck(devp != NULL);
 
  osalDbgAssert((devp->state == LSM303AGR_STOP) ||
                (devp->state == LSM303AGR_READY),
                "lsm303agrStop(), invalid state");
 
  if (devp->state == LSM303AGR_READY) {
#if LSM303AGR_SHARED_I2C
    i2cAcquireBus((devp)->config->i2cp);
    i2cStart((devp)->config->i2cp, (devp)->config->i2ccfg);
#endif /* LSM303AGR_SHARED_I2C */
 
    /* Disabling accelerometer. */
    cr[0] = LSM303AGR_AD_CTRL_REG1_A;
    cr[1] = LSM303AGR_ACC_AE_DISABLED | LSM303AGR_ACC_ODR_PD;
    lsm303agrI2CWriteRegister(devp->config->i2cp, LSM303AGR_SAD_ACC,
                               cr, 1);
 
    /* Disabling compass. */
    cr[0] = LSM303AGR_AD_CFG_REG_A_M;
    cr[1] = LSM303AGR_COMP_MODE_IDLE;
    lsm303agrI2CWriteRegister(devp->config->i2cp, LSM303AGR_SAD_COMP,
                               cr, 1);
 
    i2cStop((devp)->config->i2cp);
#if LSM303AGR_SHARED_I2C
    i2cReleaseBus((devp)->config->i2cp);
#endif /* LSM303AGR_SHARED_I2C */
  }     
  devp->state = LSM303AGR_STOP;
}
/** @} */