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RIOT/drivers/isl29020/isl29020.c 2.87 KB
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  /*
   * Copyright (C) 2014 Freie Universitรคt Berlin
   *
   * 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_isl29020
   * @{
   *
   * @file
   * @brief       Device driver implementation for the ISL29020 light sensor
   *
   * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
   * @author      Peter Kietzmann <peter.kietzmann@haw-hamburg.de>
   *
   * @}
   */
  
  #include "isl29020.h"
  #include "isl29020-internal.h"
  #include "periph/i2c.h"
  
  #define ENABLE_DEBUG    (0)
  #include "debug.h"
  
  int isl29020_init(isl29020_t *dev, i2c_t i2c, uint8_t address,
                    isl29020_range_t range, isl29020_mode_t mode)
  {
      int res;
      uint8_t tmp;
  
      /* initialize device descriptor */
      dev->i2c = i2c;
      dev->address = address;
      dev->lux_fac = (float)((1 << (10 + (2 * range))) - 1) / 0xffff;
  
      /* acquire exclusive access to the bus */
      i2c_acquire(dev->i2c);
      /* initialize the I2C bus */
      i2c_init_master(i2c, I2C_SPEED_NORMAL);
  
      /* configure and enable the sensor */
      tmp = ISL29020_CMD_EN | ISL29020_CMD_MODE | ISL29020_RES_INT_16 | range | (mode << 5);
      res = i2c_write_reg(dev->i2c, address, ISL29020_REG_CMD, tmp);
      /* release the bus for other threads */
      i2c_release(dev->i2c);
      if (res < 1) {
          return -1;
      }
      return 0;
  }
  
  int isl29020_read(const isl29020_t *dev)
  {
      uint8_t low, high;
      uint16_t res;
      int ret;
  
      i2c_acquire(dev->i2c);
      /* read lighting value */
      ret = i2c_read_reg(dev->i2c, dev->address, ISL29020_REG_LDATA, &low);
      ret += i2c_read_reg(dev->i2c, dev->address, ISL29020_REG_HDATA, &high);
      i2c_release(dev->i2c);
      if (ret < 2) {
          return -1;
      }
      res = (high << 8) | low;
      DEBUG("ISL29020: Raw value: %i - high: %i, low: %i\n", res, high, low);
      /* calculate and return the actual lux value */
      return (int)(dev->lux_fac * res);
  }
  
  int isl29020_enable(const isl29020_t *dev)
  {
      int res;
      uint8_t tmp;
  
      i2c_acquire(dev->i2c);
      res = i2c_read_reg(dev->i2c, dev->address, ISL29020_REG_CMD, &tmp);
      if (res < 1) {
          i2c_release(dev->i2c);
          return -1;
      }
      tmp |= ISL29020_CMD_EN;
      res = i2c_write_reg(dev->i2c, dev->address, ISL29020_REG_CMD, tmp);
      if (res < 1) {
          i2c_release(dev->i2c);
          return -1;
      }
      i2c_release(dev->i2c);
      return 0;
  }
  
  int isl29020_disable(const isl29020_t *dev)
  {
      int res;
      uint8_t tmp;
  
      i2c_acquire(dev->i2c);
      res = i2c_read_reg(dev->i2c, dev->address, ISL29020_REG_CMD, &tmp);
      if (res < 1) {
          i2c_release(dev->i2c);
          return -1;
      }
      tmp &= ~(ISL29020_CMD_EN);
      res = i2c_write_reg(dev->i2c, dev->address, ISL29020_REG_CMD, tmp);
      if (res < 1) {
          i2c_release(dev->i2c);
          return -1;
      }
      i2c_release(dev->i2c);
      return 0;
  }