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RIOT/drivers/mma8652/mma8652.c 4.85 KB
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  /*
   * Copyright (C) 2014 PHYTEC Messtechnik GmbH
   *
   * This file is subject to the terms and conditions of the GNU Lesser
   * General Public License v2.1. See the file LICENSE in the top level
   * directory for more details.
   *
   */
  
  /**
   * @ingroup     drivers_mma8652
   * @{
   *
   * @file
   * @brief       Driver for the Freescale MMA8652 accelerometer.
   *
   * @author      Johann Fischer <j.fischer@phytec.de>
   * @author      Peter Kietzmann <peter.kietzmann@haw-hamburg.de>
   *
   * @}
   */
  
  #include <stdint.h>
  #include <stdbool.h>
  #include "periph/i2c.h"
  #include "mma8652.h"
  #include "mma8652_reg.h"
  
  #define ENABLE_DEBUG    (0)
  #include "debug.h"
  
  #define I2C_SPEED                  I2C_SPEED_FAST
  
  int mma8652_test(mma8652_t *dev)
  {
      uint8_t reg;
  
      /* Acquire exclusive access to the bus. */
      i2c_acquire(dev->i2c);
      if (i2c_read_regs(dev->i2c, dev->addr, MMA8652_WHO_AM_I, &reg, 1) != 1) {
          /* Release the bus for other threads. */
          i2c_release(dev->i2c);
          return -1;
      }
      i2c_release(dev->i2c);
  
      if (reg != mma8x5x_device_id[dev->type]) {
          return -1;
      }
  
      return 0;
  }
  
  int mma8652_init(mma8652_t *dev, i2c_t i2c, uint8_t address, uint8_t dr, uint8_t range, uint8_t type)
  {
      uint8_t reg;
  
      /* write device descriptor */
      dev->i2c = i2c;
      dev->addr = address;
      dev->initialized = false;
  
      if (dr > MMA8652_DATARATE_1HZ56 || range > MMA8652_FS_RANGE_8G || type >= MMA8x5x_TYPE_MAX) {
          return -1;
      }
  
      dev->type = type;
  
      i2c_acquire(dev->i2c);
      /* initialize the I2C bus */
      if (i2c_init_master(i2c, I2C_SPEED) < 0) {
          i2c_release(dev->i2c);
          return -2;
      }
      i2c_release(dev->i2c);
  
      if (mma8652_test(dev)) {
          return -3;
      }
  
      if (mma8652_set_standby(dev) < 0) {
          return -4;
      }
  
      reg = MMA8652_XYZ_DATA_CFG_FS(range);
  
      i2c_acquire(dev->i2c);
      if (i2c_write_regs(dev->i2c, dev->addr, MMA8652_XYZ_DATA_CFG, &reg, 1) != 1) {
          i2c_release(dev->i2c);
          return -5;
      }
  
      reg = MMA8652_CTRL_REG1_DR(dr);
  
      if (i2c_write_regs(dev->i2c, dev->addr, MMA8652_CTRL_REG1, &reg, 1) != 1) {
          i2c_release(dev->i2c);
          return -5;
      }
      i2c_release(dev->i2c);
  
      dev->initialized = true;
      dev->scale = 1024 >> range;
  
      return 0;
  }
  
  int mma8652_set_user_offset(mma8652_t *dev, int8_t x, int8_t y, int8_t z)
  {
      uint8_t buf[3];
  
      buf[0] = (uint8_t)x;
      buf[1] = (uint8_t)y;
      buf[2] = (uint8_t)z;
  
      i2c_acquire(dev->i2c);
      if (i2c_write_regs(dev->i2c, dev->addr, MMA8652_OFF_X, buf, 3) != 3) {
          i2c_release(dev->i2c);
          return -1;
      }
      i2c_release(dev->i2c);
  
      return 0;
  }
  
  int mma8652_reset(mma8652_t *dev)
  {
      uint8_t reg;
  
      dev->initialized = false;
      reg = MMA8652_CTRL_REG2_RST;
  
      i2c_acquire(dev->i2c);
      if (i2c_write_regs(dev->i2c, dev->addr, MMA8652_CTRL_REG2, &reg, 1) != 1) {
          i2c_release(dev->i2c);
          return -1;
      }
      i2c_release(dev->i2c);
  
      return 0;
  }
  
  int mma8652_set_active(mma8652_t *dev)
  {
      uint8_t reg;
  
      if (dev->initialized == false) {
          return -1;
      }
  
      i2c_acquire(dev->i2c);
      if (i2c_read_regs(dev->i2c, dev->addr, MMA8652_CTRL_REG1, &reg, 1) != 1) {
          i2c_release(dev->i2c);
          return -1;
      }
  
      reg |= MMA8652_CTRL_REG1_ACTIVE;
  
      if (i2c_write_regs(dev->i2c, dev->addr, MMA8652_CTRL_REG1, &reg, 1) != 1) {
          i2c_release(dev->i2c);
          return -1;
      }
      i2c_release(dev->i2c);
  
      return 0;
  }
  
  int mma8652_set_standby(mma8652_t *dev)
  {
      uint8_t reg;
  
      i2c_acquire(dev->i2c);
      if (i2c_read_regs(dev->i2c, dev->addr, MMA8652_CTRL_REG1, &reg, 1) != 1) {
          i2c_release(dev->i2c);
          return -1;
      }
  
      reg &= ~MMA8652_CTRL_REG1_ACTIVE;
  
      if (i2c_write_regs(dev->i2c, dev->addr, MMA8652_CTRL_REG1, &reg, 1) != 1) {
          i2c_release(dev->i2c);
          return -1;
      }
      i2c_release(dev->i2c);
  
      return 0;
  }
  
  int mma8652_is_ready(mma8652_t *dev)
  {
      uint8_t reg;
  
      if (dev->initialized == false) {
          return -1;
      }
  
      i2c_acquire(dev->i2c);
      if (i2c_read_regs(dev->i2c, dev->addr, MMA8652_STATUS, &reg, 1) != 1) {
          i2c_release(dev->i2c);
          return -1;
      }
      i2c_release(dev->i2c);
  
      return reg & MMA8652_STATUS_ZYXDR;
  }
  
  int mma8652_read(mma8652_t *dev, int16_t *x, int16_t *y, int16_t *z, uint8_t *status)
  {
      uint8_t buf[7];
  
      if (dev->initialized == false) {
          return -1;
      }
  
      i2c_acquire(dev->i2c);
      if (i2c_read_regs(dev->i2c, dev->addr, MMA8652_STATUS, buf, 7) != 7) {
          i2c_release(dev->i2c);
          return -1;
      }
      i2c_release(dev->i2c);
  
      *status = buf[0];
      *x = (int32_t)((int16_t)(((int16_t)buf[1] << 8) | buf[2]) >> 4) * 1000 / dev->scale;
      *y = (int32_t)((int16_t)(((int16_t)buf[3] << 8) | buf[4]) >> 4) * 1000 / dev->scale;
      *z = (int32_t)((int16_t)(((int16_t)buf[5] << 8) | buf[6]) >> 4) * 1000 / dev->scale;
  
      return 0;
  }