text: /**
  * Copyright (c) 2020 Bosch Sensortec GmbH. All rights reserved.
  *
  * BSD-3-Clause
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * 3. Neither the name of the copyright holder nor the names of its
  *    contributors may be used to endorse or promote products derived from
  *    this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  *
  * @file       bme280.c
  * @date       2020-03-28
  * @version    v3.5.0
  *
  */
  
  /*! @file bme280.c
   * @brief Sensor driver for BME280 sensor
   */
  #include "bme280.h"
  #include "stdio.h"
  /**\name Internal macros */
  /* To identify osr settings selected by user */
  #define OVERSAMPLING_SETTINGS UINT8_C(0x07)
  
  /* To identify filter and standby settings selected by user */
  #define FILTER_STANDBY_SETTINGS UINT8_C(0x18)
  
  /*!
   * @brief This internal API puts the device to sleep mode.
   *
   * @param[in] dev : Structure instance of bme280_dev.
   *
   * @return Result of API execution status.
   *
   * @retval   0 -> Success.
   * @retval > 0 -> Warning.
   * @retval < 0 -> Fail.
   *
   */
  static int8_t put_device_to_sleep(struct bme280_dev *dev);
  
  /*!
   * @brief This internal API writes the power mode in the sensor.
   *
   * @param[in] dev         : Structure instance of bme280_dev.
   * @param[in] sensor_mode : Variable which contains the power mode to be set.
   *
   * @return Result of API execution status.
   *
   * @retval   0 -> Success.
   * @retval > 0 -> Warning.
   * @retval < 0 -> Fail.
   *
   */
  static int8_t write_power_mode(uint8_t sensor_mode, struct bme280_dev *dev);
  
  /*!
   * @brief This internal API is used to validate the device pointer for
   * null conditions.
   *
   * @param[in] dev : Structure instance of bme280_dev.
   *
   * @return Result of API execution status
   *
   * @retval   0 -> Success.
   * @retval > 0 -> Warning.
   * @retval < 0 -> Fail.
   *
   */
  static int8_t null_ptr_check(const struct bme280_dev *dev);
  
  /*!
   * @brief This internal API interleaves the register address between the
   * register data buffer for burst write operation.
   *
   * @param[in] reg_addr   : Contains the register address array.
   * @param[out] temp_buff : Contains the temporary buffer to store the
   * register data and register address.
   * @param[in] reg_data   : Contains the register data to be written in the
   * temporary buffer.
   * @param[in] len        : No of bytes of data to be written for burst write.
   *
   */
  static void interleave_reg_addr(const uint8_t *reg_addr, uint8_t *temp_buff, const uint8_t *reg_data, uint8_t len);
  
  /*!
   * @brief This internal API reads the calibration data from the sensor, parse
   * it and store in the device structure.
   *
   * @param[in] dev : Structure instance of bme280_dev.
   *
   * @return Result of API execution status
   *
   * @retval   0 -> Success.
   * @retval > 0 -> Warning.
   * @retval < 0 -> Fail.
   *
   */
  static int8_t get_calib_data(struct bme280_dev *dev);
  
  /*!
   *  @brief This internal API is used to parse the temperature and
   *  pressure calibration data and store it in the device structure.
   *
   *  @param[out] dev     : Structure instance of bme280_dev to store the calib data.
   *  @param[in] reg_data : Contains the calibration data to be parsed.
   *
   */
  static void parse_temp_press_calib_data(const uint8_t *reg_data, struct bme280_dev *dev);
  
  /*!
   *  @brief This internal API is used to parse the humidity calibration data
   *  and store it in device structure.
   *
   *  @param[out] dev     : Structure instance of bme280_dev to store the calib data.
   *  @param[in] reg_data : Contains calibration data to be parsed.
   *
   */
  static void parse_humidity_calib_data(const uint8_t *reg_data, struct bme280_dev *dev);
  
  #ifdef BME280_FLOAT_ENABLE
  
  /*!
   * @brief This internal API is used to compensate the raw pressure data and
   * return the compensated pressure data in double data type.
   *
   * @param[in] uncomp_data : Contains the uncompensated pressure data.
   * @param[in] calib_data  : Pointer to the calibration data structure.
   *
   * @return Compensated pressure data in double.
   *
   */
  static double compensate_pressure(const struct bme280_uncomp_data *uncomp_data,
                                    const struct bme280_calib_data *calib_data);
  
  /*!
   * @brief This internal API is used to compensate the raw humidity data and
   * return the compensated humidity data in double data type.
   *
   * @param[in] uncomp_data : Contains the uncompensated humidity data.
   * @param[in] calib_data  : Pointer to the calibration data structure.
   *
   * @return Compensated humidity data in double.
   *
   */
  static double compensate_humidity(const struct bme280_uncomp_data *uncomp_data,
                                    const struct bme280_calib_data *calib_data);
  
  /*!
   * @brief This internal API is used to compensate the raw temperature data and
   * return the compensated temperature data in double data type.
   *
   * @param[in] uncomp_data : Contains the uncompensated temperature data.
   * @param[in] calib_data  : Pointer to calibration data structure.
   *
   * @return Compensated temperature data in double.
   *
   */
  static double compensate_temperature(const struct bme280_uncomp_data *uncomp_data,
                                       struct bme280_calib_data *calib_data);
  
  #else
  
  /*!
   * @brief This internal API is used to compensate the raw temperature data and
   * return the compensated temperature data in integer data type.
   *
   * @param[in] uncomp_data : Contains the uncompensated temperature data.
   * @param[in] calib_data  : Pointer to calibration data structure.
   *
   * @return Compensated temperature data in integer.
   *
   */
  static int32_t compensate_temperature(const struct bme280_uncomp_data *uncomp_data,
                                        struct bme280_calib_data *calib_data);
  
  /*!
   * @brief This internal API is used to compensate the raw pressure data and
   * return the compensated pressure data in integer data type.
   *
   * @param[in] uncomp_data : Contains the uncompensated pressure data.
   * @param[in] calib_data  : Pointer to the calibration data structure.
   *
   * @return Compensated pressure data in integer.
   *
   */
  static uint32_t compensate_pressure(const struct bme280_uncomp_data *uncomp_data,
                                      const struct bme280_calib_data *calib_data);
  
  /*!
   * @brief This internal API is used to compensate the raw humidity data and
   * return the compensated humidity data in integer data type.
   *
   * @param[in] uncomp_data : Contains the uncompensated humidity data.
   * @param[in] calib_data  : Pointer to the calibration data structure.
   *
   * @return Compensated humidity data in integer.
   *
   */
  static uint32_t compensate_humidity(const struct bme280_uncomp_data *uncomp_data,
                                      const struct bme280_calib_data *calib_data);
  
  #endif
  
  /*!
   * @brief This internal API is used to identify the settings which the user
   * wants to modify in the sensor.
   *
   * @param[in] sub_settings     : Contains the settings subset to identify particular
   * group of settings which the user is interested to change.
   * @param[in] desired_settings : Contains the user specified settings.
   *
   * @return Indicates whether user is interested to modify the settings which
   * are related to sub_settings.
   * @return True -> User wants to modify this group of settings
   * @return False -> User does not want to modify this group of settings
   *
   */
  static uint8_t are_settings_changed(uint8_t sub_settings, uint8_t desired_settings);
  
  /*!
   * @brief This API sets the humidity over sampling settings of the sensor.
   *
   * @param[in] dev      : Structure instance of bme280_dev.
   * @param[in] settings : Pointer variable which contains the settings to
   * be set in the sensor.
   *
   * @return Result of API execution status
   *
   * @retval   0 -> Success.
   * @retval > 0 -> Warning.
   * @retval < 0 -> Fail.
   *
   */
  static int8_t set_osr_humidity_settings(const struct bme280_settings *settings, struct bme280_dev *dev);
  
  /*!
   * @brief This internal API sets the oversampling settings for pressure,
   * temperature and humidity in the sensor.
   *
   * @param[in] desired_settings : Variable used to select the settings which
   * are to be set.
   * @param[in] settings         : Pointer variable which contains the settings to
   * be set in the sensor.
   * @param[in] dev              : Structure instance of bme280_dev.
   *
   * @return Result of API execution status
   *
   * @retval   0 -> Success.
   * @retval > 0 -> Warning.
   * @retval < 0 -> Fail.
   *
   */
  static int8_t set_osr_settings(uint8_t desired_settings, const struct bme280_settings *settings,
                                 struct bme280_dev *dev);
  
  /*!
   * @brief This API sets the pressure and/or temperature oversampling settings
   * in the sensor according to the settings selected by the user.
   *
   * @param[in] dev : Structure instance of bme280_dev.
   * @param[in] desired_settings: variable to select the pressure and/or
   * temperature oversampling settings.
   * @param[in] settings : Pointer variable which contains the settings to
   * be set in the sensor.
   *
   * @return Result of API execution status
   *
   * @retval   0 -> Success.
   * @retval > 0 -> Warning.
   * @retval < 0 -> Fail.
   *
   */
  static int8_t set_osr_press_temp_settings(uint8_t desired_settings,
                                            const struct bme280_settings *settings,
                                            struct bme280_dev *dev);
  
  /*!
   * @brief This internal API fills the pressure oversampling settings provided by
   * the user in the data buffer so as to write in the sensor.
   *
   * @param[in] settings : Pointer variable which contains the settings to
   * be set in the sensor.
   * @param[out] reg_data : Variable which is filled according to the pressure
   * oversampling data provided by the user.
   *
   */
  static void fill_osr_press_settings(uint8_t *reg_data, const struct bme280_settings *settings);
  
  /*!
   * @brief This internal API fills the temperature oversampling settings provided
   * by the user in the data buffer so as to write in the sensor.
   *
   * @param[in] settings : Pointer variable which contains the settings to
   * be set in the sensor.
   * @param[out] reg_data : Variable which is filled according to the temperature
   * oversampling data provided by the user.
   *
   */
  static void fill_osr_temp_settings(uint8_t *reg_data, const struct bme280_settings *settings);
  
  /*!
   * @brief This internal API sets the filter and/or standby duration settings
   * in the sensor according to the settings selected by the user.
   *
   * @param[in] dev : Structure instance of bme280_dev.
   * @param[in] settings : Pointer variable which contains the settings to
   * be set in the sensor.
   * @param[in] settings : Structure instance of bme280_settings.
   *
   * @return Result of API execution status
   *
   * @retval   0 -> Success.
   * @retval > 0 -> Warning.
   * @retval < 0 -> Fail.
   *
   */
  static int8_t set_filter_standby_settings(uint8_t desired_settings,
                                            const struct bme280_settings *settings,
                                            struct bme280_dev *dev);
  
  /*!
   * @brief This internal API fills the filter settings provided by the user
   * in the data buffer so as to write in the sensor.
   *
   * @param[in] settings : Pointer variable which contains the settings to
   * be set in the sensor.
   * @param[out] reg_data : Variable which is filled according to the filter
   * settings data provided by the user.
   *
   */
  static void fill_filter_settings(uint8_t *reg_data, const struct bme280_settings *settings);
  
  /*!
   * @brief This internal API fills the standby duration settings provided by the
   * user in the data buffer so as to write in the sensor.
   *
   * @param[in] settings : Pointer variable which contains the settings to
   * be set in the sensor.
   * @param[out] reg_data : Variable which is filled according to the standby
   * settings data provided by the user.
   *
   */
  static void fill_standby_settings(uint8_t *reg_data, const struct bme280_settings *settings);
  
  /*!
   * @brief This internal API parse the oversampling(pressure, temperature
   * and humidity), filter and standby duration settings and store in the
   * device structure.
   *
   * @param[in] settings : Pointer variable which contains the settings to
   * be get in the sensor.
   * @param[in] reg_data : Register data to be parsed.
   *
   */
  static void parse_device_settings(const uint8_t *reg_data, struct bme280_settings *settings);
  
  /*!
   * @brief This internal API reloads the already existing device settings in the
   * sensor after soft reset.
   *
   * @param[in] dev : Structure instance of bme280_dev.
   * @param[in] settings : Pointer variable which contains the settings to
   * be set in the sensor.
   *
   * @return Result of API execution status
   *
   * @retval   0 -> Success.
   * @retval > 0 -> Warning.
   * @retval < 0 -> Fail.
   *
   */
  static int8_t reload_device_settings(const struct bme280_settings *settings, struct bme280_dev *dev);
  
  /****************** Global Function Definitions *******************************/
  
  /*!
   *  @brief This API is the entry point.
   *  It reads the chip-id and calibration data from the sensor.
   */
  int8_t bme280_init(struct bme280_dev *dev)
  {
      int8_t rslt;
  
      /* chip id read try count */
      uint8_t try_count = 5;
      uint8_t chip_id = 0;
  
      /* Check for null pointer in the device structure*/
      rslt = null_ptr_check(dev);
  
      /* Proceed if null check is fine */
      if(rslt == BME280_OK)
      {
          while(try_count)
          {
              /* Read the chip-id of bme280 sensor */
              rslt = bme280_get_regs(BME280_CHIP_ID_ADDR, &chip_id, 1, dev);
  
              printf("chip_id: %x", chip_id);
              /* Check for chip id validity */
              if((rslt == BME280_OK) && (chip_id == BME280_CHIP_ID))
              {
                  dev->chip_id = chip_id;
  
                  /* Reset the sensor */
                  rslt = bme280_soft_reset(dev);
  
                  if(rslt == BME280_OK)
                  {
                      /* Read the calibration data */
                      rslt = get_calib_data(dev);
                  }
  
                  break;
              }
  
              /* Wait for 1 ms */
              dev->delay_us(1000, dev->intf_ptr);
              --try_count;
          }
  
          /* Chip id check failed */
          if(!try_count)
          {
              rslt = BME280_E_DEV_NOT_FOUND;
          }
      }
  
      return rslt;
  }
  
  /*!
   * @brief This API reads the data from the given register address of the sensor.
   */
  int8_t bme280_get_regs(uint8_t reg_addr, uint8_t *reg_data, uint16_t len, struct bme280_dev *dev)
  {
      int8_t rslt;
  
      /* Check for null pointer in the device structure*/
      rslt = null_ptr_check(dev);
  
      /* Proceed if null check is fine */
      if((rslt == BME280_OK) && (reg_data != NULL))
      {
          /* If interface selected is SPI */
          if(dev->intf != BME280_I2C_INTF)
          {
              reg_addr = reg_addr | 0x80;
          }
  
          /* Read the data  */
          dev->intf_rslt = dev->read(reg_addr, reg_data, len, dev->intf_ptr);
          /* Check for communication error */
          if(dev->intf_rslt != BME280_INTF_RET_SUCCESS)
          {
              rslt = BME280_E_COMM_FAIL;
          }
      } else
      {
          rslt = BME280_E_NULL_PTR;
      }
      return rslt;
  }
  
  /*!
   * @brief This API writes the given data to the register address
   * of the sensor.
   */
  int8_t bme280_set_regs(uint8_t *reg_addr, const uint8_t *reg_data, uint8_t len, struct bme280_dev *dev)
  {
      int8_t rslt;
      uint8_t temp_buff[20]; /* Typically not to write more than 10 registers */
  
      if(len > 10)
      {
          len = 10;
      }
  
      uint16_t temp_len;
      uint8_t reg_addr_cnt;
  
      /* Check for null pointer in the device structure*/
      rslt = null_ptr_check(dev);
  
      /* Check for arguments validity */
      if((rslt == BME280_OK) && (reg_addr != NULL) && (reg_data != NULL))
      {
          if(len != 0)
          {
              temp_buff[0] = reg_data[0];
  
              /* If interface selected is SPI */
              if(dev->intf != BME280_I2C_INTF)
              {
                  for(reg_addr_cnt = 0; reg_addr_cnt < len; reg_addr_cnt++)
                  {
                      reg_addr[reg_addr_cnt] = reg_addr[reg_addr_cnt] & 0x7F;
                  }
              }
  
              /* Burst write mode */
              if(len > 1)
              {
                  /* Interleave register address w.r.t data for
                   * burst write
                   */
                  interleave_reg_addr(reg_addr, temp_buff, reg_data, len);
                  temp_len = ((len * 2) - 1);
              } else
              {
                  temp_len = len;
              }
  
              dev->intf_rslt = dev->write(reg_addr[0], temp_buff, temp_len, dev->intf_ptr);
  
              /* Check for communication error */
              if(dev->intf_rslt != BME280_INTF_RET_SUCCESS)
              {
                  rslt = BME280_E_COMM_FAIL;
              }
          } else
          {
              rslt = BME280_E_INVALID_LEN;
          }
      } else
      {
          rslt = BME280_E_NULL_PTR;
      }
  
      return rslt;
  }
  
  /*!
   * @brief This API sets the oversampling, filter and standby duration
   * (normal mode) settings in the sensor.
   */
  int8_t bme280_set_sensor_settings(uint8_t desired_settings, struct bme280_dev *dev)
  {
      int8_t rslt;
      uint8_t sensor_mode;
  
      /* Check for null pointer in the device structure*/
      rslt = null_ptr_check(dev);
  
      /* Proceed if null check is fine */
      if(rslt == BME280_OK)
      {
          rslt = bme280_get_sensor_mode(&sensor_mode, dev);
  
          if((rslt == BME280_OK) && (sensor_mode != BME280_SLEEP_MODE))
          {
              rslt = put_device_to_sleep(dev);
          }
  
          if(rslt == BME280_OK)
          {
              /* Check if user wants to change oversampling
               * settings
               */
              if(are_settings_changed(OVERSAMPLING_SETTINGS, desired_settings))
              {
                  rslt = set_osr_settings(desired_settings, &dev->settings, dev);
              }
  
              /* Check if user wants to change filter and/or
               * standby settings
               */
              if((rslt == BME280_OK) && are_settings_changed(FILTER_STANDBY_SETTINGS, desired_settings))
              {
                  rslt = set_filter_standby_settings(desired_settings, &dev->settings, dev);
              }
          }
      }
  
      return rslt;
  }
  
  /*!
   * @brief This API gets the oversampling, filter and standby duration
   * (normal mode) settings from the sensor.
   */
  int8_t bme280_get_sensor_settings(struct bme280_dev *dev)
  {
      int8_t rslt;
      uint8_t reg_data[4];
  
      /* Check for null pointer in the device structure*/
      rslt = null_ptr_check(dev);
  
      /* Proceed if null check is fine */
      if(rslt == BME280_OK)
      {
          rslt = bme280_get_regs(BME280_CTRL_HUM_ADDR, reg_data, 4, dev);
  
          if(rslt == BME280_OK)
          {
              parse_device_settings(reg_data, &dev->settings);
          }
      }
  
      return rslt;
  }
  
  /*!
   * @brief This API sets the power mode of the sensor.
   */
  int8_t bme280_set_sensor_mode(uint8_t sensor_mode, struct bme280_dev *dev)
  {
      int8_t rslt;
      uint8_t last_set_mode;
  
      /* Check for null pointer in the device structure*/
      rslt = null_ptr_check(dev);
  
      if(rslt == BME280_OK)
      {
          rslt = bme280_get_sensor_mode(&last_set_mode, dev);
  
          /* If the sensor is not in sleep mode put the device to sleep
           * mode
           */
          if((rslt == BME280_OK) && (last_set_mode != BME280_SLEEP_MODE))
          {
              rslt = put_device_to_sleep(dev);
          }
  
          /* Set the power mode */
          if(rslt == BME280_OK)
          {
              rslt = write_power_mode(sensor_mode, dev);
          }
      }
  
      return rslt;
  }
  
  /*!
   * @brief This API gets the power mode of the sensor.
   */
  int8_t bme280_get_sensor_mode(uint8_t *sensor_mode, struct bme280_dev *dev)
  {
      int8_t rslt;
  
      /* Check for null pointer in the device structure*/
      rslt = null_ptr_check(dev);
  
      if((rslt == BME280_OK) && (sensor_mode != NULL))
      {
          /* Read the power mode register */
          rslt = bme280_get_regs(BME280_PWR_CTRL_ADDR, sensor_mode, 1, dev);
  
          /* Assign the power mode in the device structure */
          *sensor_mode = BME280_GET_BITS_POS_0(*sensor_mode, BME280_SENSOR_MODE);
      } else
      {
          rslt = BME280_E_NULL_PTR;
      }
  
      return rslt;
  }
  
  /*!
   * @brief This API performs the soft reset of the sensor.
   */
  int8_t bme280_soft_reset(struct bme280_dev *dev)
  {
      int8_t rslt;
      uint8_t reg_addr = BME280_RESET_ADDR;
      uint8_t status_reg = 0;
      uint8_t try_run = 5;
  
      /* 0xB6 is the soft reset command */
      uint8_t soft_rst_cmd = BME280_SOFT_RESET_COMMAND;
  
      /* Check for null pointer in the device structure*/
      rslt = null_ptr_check(dev);
  
      /* Proceed if null check is fine */
      if(rslt == BME280_OK)
      {
          /* Write the soft reset command in the sensor */
          rslt = bme280_set_regs(&reg_addr, &soft_rst_cmd, 1, dev);
  
          if(rslt == BME280_OK)
          {
              /* If NVM not copied yet, Wait for NVM to copy */
              do
              {
                  /* As per data sheet - Table 1, startup time is 2 ms. */
                  dev->delay_us(2000, dev->intf_ptr);
                  rslt = bme280_get_regs(BME280_STATUS_REG_ADDR, &status_reg, 1, dev);
  
              } while((rslt == BME280_OK) && (try_run--) && (status_reg & BME280_STATUS_IM_UPDATE));
  
              if(status_reg & BME280_STATUS_IM_UPDATE)
              {
                  rslt = BME280_E_NVM_COPY_FAILED;
              }
          }
      }
  
      return rslt;
  }
  
  /*!
   * @brief This API reads the pressure, temperature and humidity data from the
   * sensor, compensates the data and store it in the bme280_data structure
   * instance passed by the user.
   */
  int8_t bme280_get_sensor_data(uint8_t sensor_comp, struct bme280_data *comp_data, struct bme280_dev *dev)
  {
      int8_t rslt;
  
      /* Array to store the pressure, temperature and humidity data read from
       * the sensor
       */
      uint8_t reg_data[BME280_P_T_H_DATA_LEN] = {0};
      struct bme280_uncomp_data uncomp_data = {0};
  
      /* Check for null pointer in the device structure*/
      rslt = null_ptr_check(dev);
  
      if((rslt == BME280_OK) && (comp_data != NULL))
      {
          /* Read the pressure and temperature data from the sensor */
          rslt = bme280_get_regs(BME280_DATA_ADDR, reg_data, BME280_P_T_H_DATA_LEN, dev);
  
          if(rslt == BME280_OK)
          {
              /* Parse the read data from the sensor */
              bme280_parse_sensor_data(reg_data, &uncomp_data);
  
              /* Compensate the pressure and/or temperature and/or
               * humidity data from the sensor
               */
              rslt = bme280_compensate_data(sensor_comp, &uncomp_data, comp_data, &dev->calib_data);
          }
      } else
      {
          rslt = BME280_E_NULL_PTR;
      }
  
      return rslt;
  }
  
  /*!
   *  @brief This API is used to parse the pressure, temperature and
   *  humidity data and store it in the bme280_uncomp_data structure instance.
   */
  void bme280_parse_sensor_data(const uint8_t *reg_data, struct bme280_uncomp_data *uncomp_data)
  {
      /* Variables to store the sensor data */
      uint32_t data_xlsb;
      uint32_t data_lsb;
      uint32_t data_msb;
  
      /* Store the parsed register values for pressure data */
      data_msb = (uint32_t)reg_data[0] << 12;
      data_lsb = (uint32_t)reg_data[1] << 4;
      data_xlsb = (uint32_t)reg_data[2] >> 4;
      uncomp_data->pressure = data_msb | data_lsb | data_xlsb;
      // uncomp_data->pressure /= 10000;
  
      /* Store the parsed register values for temperature data */
      data_msb = (uint32_t)reg_data[3] << 12;
      data_lsb = (uint32_t)reg_data[4] << 4;
      data_xlsb = (uint32_t)reg_data[5] >> 4;
      uncomp_data->temperature = data_msb | data_lsb | data_xlsb;
      // uncomp_data->temperature /= 100;
  
      /* Store the parsed register values for humidity data */
      data_msb = (uint32_t)reg_data[6] << 8;
      data_lsb = (uint32_t)reg_data[7];
      uncomp_data->humidity = data_msb | data_lsb;
      // uncomp_data->humidity /= 1000;
  }
  
  /*!
   * @brief This API is used to compensate the pressure and/or
   * temperature and/or humidity data according to the component selected
   * by the user.
   */
  int8_t bme280_compensate_data(uint8_t sensor_comp,
                                const struct bme280_uncomp_data *uncomp_data,
                                struct bme280_data *comp_data,
                                struct bme280_calib_data *calib_data)
  {
      int8_t rslt = BME280_OK;
  
      if((uncomp_data != NULL) && (comp_data != NULL) && (calib_data != NULL))
      {
          /* Initialize to zero */
          comp_data->temperature = 0;
          comp_data->pressure = 0;
          comp_data->humidity = 0;
  
          /* If pressure or temperature component is selected */
          if(sensor_comp & (BME280_PRESS | BME280_TEMP | BME280_HUM))
          {
              /* Compensate the temperature data */
              comp_data->temperature = compensate_temperature(uncomp_data, calib_data);
          }
  
          if(sensor_comp & BME280_PRESS)
          {
              /* Compensate the pressure data */
              comp_data->pressure = compensate_pressure(uncomp_data, calib_data);
          }
  
          if(sensor_comp & BME280_HUM)
          {
              /* Compensate the humidity data */
              comp_data->humidity = compensate_humidity(uncomp_data, calib_data);
          }
      } else
      {
          rslt = BME280_E_NULL_PTR;
      }
  
      return rslt;
  }
  
  /*!
   * @brief This API is used to calculate the maximum delay in milliseconds required for the
   * temperature/pressure/humidity(which ever at enabled) measurement to complete.
   */
  uint32_t bme280_cal_meas_delay(const struct bme280_settings *settings)
  {
      uint32_t max_delay;
      uint8_t temp_osr;
      uint8_t pres_osr;
      uint8_t hum_osr;
  
      /*Array to map OSR config register value to actual OSR */
      uint8_t osr_sett_to_act_osr[] = {0, 1, 2, 4, 8, 16};
  
      /* Mapping osr settings to the actual osr values e.g. 0b101 -> osr X16  */
      if(settings->osr_t <= 5)
      {
          temp_osr = osr_sett_to_act_osr[settings->osr_t];
      } else
      {
          temp_osr = 16;
      }
  
      if(settings->osr_p <= 5)
      {
          pres_osr = osr_sett_to_act_osr[settings->osr_p];
      } else
      {
          pres_osr = 16;
      }
  
      if(settings->osr_h <= 5)
      {
          hum_osr = osr_sett_to_act_osr[settings->osr_h];
      } else
      {
          hum_osr = 16;
      }
  
      max_delay =
          (uint32_t)((BME280_MEAS_OFFSET + (BME280_MEAS_DUR * temp_osr) +
                      ((BME280_MEAS_DUR * pres_osr) + BME280_PRES_HUM_MEAS_OFFSET) +
                      ((BME280_MEAS_DUR * hum_osr) + BME280_PRES_HUM_MEAS_OFFSET)) /
                     BME280_MEAS_SCALING_FACTOR);
  
      return max_delay;
  }
  
  /*!
   * @brief This internal API sets the oversampling settings for pressure,
   * temperature and humidity in the sensor.
   */
  static int8_t set_osr_settings(uint8_t desired_settings, const struct bme280_settings *settings, struct bme280_dev *dev)
  {
      int8_t rslt = BME280_W_INVALID_OSR_MACRO;
  
      if(desired_settings & BME280_OSR_HUM_SEL)
      {
          rslt = set_osr_humidity_settings(settings, dev);
      }
  
      if(desired_settings & (BME280_OSR_PRESS_SEL | BME280_OSR_TEMP_SEL))
      {
          rslt = set_osr_press_temp_settings(desired_settings, settings, dev);
      }
  
      return rslt;
  }
  
  /*!
   * @brief This API sets the humidity oversampling settings of the sensor.
   */
  static int8_t set_osr_humidity_settings(const struct bme280_settings *settings, struct bme280_dev *dev)
  {
      int8_t rslt;
      uint8_t ctrl_hum;
      uint8_t ctrl_meas;
      uint8_t reg_addr = BME280_CTRL_HUM_ADDR;
  
      ctrl_hum = settings->osr_h & BME280_CTRL_HUM_MSK;
  
      /* Write the humidity control value in the register */
      rslt = bme280_set_regs(&reg_addr, &ctrl_hum, 1, dev);
  
      /* Humidity related changes will be only effective after a
       * write operation to ctrl_meas register
       */
      if(rslt == BME280_OK)
      {
          reg_addr = BME280_CTRL_MEAS_ADDR;
          rslt = bme280_get_regs(reg_addr, &ctrl_meas, 1, dev);
  
          if(rslt == BME280_OK)
          {
              rslt = bme280_set_regs(&reg_addr, &ctrl_meas, 1, dev);
          }
      }
  
      return rslt;
  }
  
  /*!
   * @brief This API sets the pressure and/or temperature oversampling settings
   * in the sensor according to the settings selected by the user.
   */
  static int8_t set_osr_press_temp_settings(uint8_t desired_settings,
                                            const struct bme280_settings *settings,
                                            struct bme280_dev *dev)
  {
      int8_t rslt;
      uint8_t reg_addr = BME280_CTRL_MEAS_ADDR;
      uint8_t reg_data;
  
      rslt = bme280_get_regs(reg_addr, &reg_data, 1, dev);
  
      if(rslt == BME280_OK)
      {
          if(desired_settings & BME280_OSR_PRESS_SEL)
          {
              fill_osr_press_settings(&reg_data, settings);
          }
  
          if(desired_settings & BME280_OSR_TEMP_SEL)
          {
              fill_osr_temp_settings(&reg_data, settings);
          }
  
          /* Write the oversampling settings in the register */
          rslt = bme280_set_regs(&reg_addr, &reg_data, 1, dev);
      }
  
      return rslt;
  }
  
  /*!
   * @brief This internal API sets the filter and/or standby duration settings
   * in the sensor according to the settings selected by the user.
   */
  static int8_t set_filter_standby_settings(uint8_t desired_settings,
                                            const struct bme280_settings *settings,
                                            struct bme280_dev *dev)
  {
      int8_t rslt;
      uint8_t reg_addr = BME280_CONFIG_ADDR;
      uint8_t reg_data;
  
      rslt = bme280_get_regs(reg_addr, &reg_data, 1, dev);
  
      if(rslt == BME280_OK)
      {
          if(desired_settings & BME280_FILTER_SEL)
          {
              fill_filter_settings(&reg_data, settings);
          }
  
          if(desired_settings & BME280_STANDBY_SEL)
          {
              fill_standby_settings(&reg_data, settings);
          }
  
          /* Write the oversampling settings in the register */
          rslt = bme280_set_regs(&reg_addr, &reg_data, 1, dev);
      }
  
      return rslt;
  }
  
  /*!
   * @brief This internal API fills the filter settings provided by the user
   * in the data buffer so as to write in the sensor.
   */
  static void fill_filter_settings(uint8_t *reg_data, const struct bme280_settings *settings)
  {
      *reg_data = BME280_SET_BITS(*reg_data, BME280_FILTER, settings->filter);
  }
  
  /*!
   * @brief This internal API fills the standby duration settings provided by
   * the user in the data buffer so as to write in the sensor.
   */
  static void fill_standby_settings(uint8_t *reg_data, const struct bme280_settings *settings)
  {
      *reg_data = BME280_SET_BITS(*reg_data, BME280_STANDBY, settings->standby_time);
  }
  
  /*!
   * @brief This internal API fills the pressure oversampling settings provided by
   * the user in the data buffer so as to write in the sensor.
   */
  static void fill_osr_press_settings(uint8_t *reg_data, const struct bme280_settings *settings)
  {
      *reg_data = BME280_SET_BITS(*reg_data, BME280_CTRL_PRESS, settings->osr_p);
  }
  
  /*!
   * @brief This internal API fills the temperature oversampling settings
   * provided by the user in the data buffer so as to write in the sensor.
   */
  static void fill_osr_temp_settings(uint8_t *reg_data, const struct bme280_settings *settings)
  {
      *reg_data = BME280_SET_BITS(*reg_data, BME280_CTRL_TEMP, settings->osr_t);
  }
  
  /*!
   * @brief This internal API parse the oversampling(pressure, temperature
   * and humidity), filter and standby duration settings and store in the
   * device structure.
   */
  static void parse_device_settings(const uint8_t *reg_data, struct bme280_settings *settings)
  {
      settings->osr_h = BME280_GET_BITS_POS_0(reg_data[0], BME280_CTRL_HUM);
      settings->osr_p = BME280_GET_BITS(reg_data[2], BME280_CTRL_PRESS);
      settings->osr_t = BME280_GET_BITS(reg_data[2], BME280_CTRL_TEMP);
      settings->filter = BME280_GET_BITS(reg_data[3], BME280_FILTER);
      settings->standby_time = BME280_GET_BITS(reg_data[3], BME280_STANDBY);
  }
  
  /*!
   * @brief This internal API writes the power mode in the sensor.
   */
  static int8_t write_power_mode(uint8_t sensor_mode, struct bme280_dev *dev)
  {
      int8_t rslt;
      uint8_t reg_addr = BME280_PWR_CTRL_ADDR;
  
      /* Variable to store the value read from power mode register */
      uint8_t sensor_mode_reg_val;
  
      /* Read the power mode register */
      rslt = bme280_get_regs(reg_addr, &sensor_mode_reg_val, 1, dev);
  
      /* Set the power mode */
      if(rslt == BME280_OK)
      {
          sensor_mode_reg_val = BME280_SET_BITS_POS_0(sensor_mode_reg_val, BME280_SENSOR_MODE, sensor_mode);
  
          /* Write the power mode in the register */
          rslt = bme280_set_regs(&reg_addr, &sensor_mode_reg_val, 1, dev);
      }
  
      return rslt;
  }
  
  /*!
   * @brief This internal API puts the device to sleep mode.
   */
  static int8_t put_device_to_sleep(struct bme280_dev *dev)
  {
      int8_t rslt;
      uint8_t reg_data[4];
      struct bme280_settings settings;
  
      rslt = bme280_get_regs(BME280_CTRL_HUM_ADDR, reg_data, 4, dev);
  
      if(rslt == BME280_OK)
      {
          parse_device_settings(reg_data, &settings);
          rslt = bme280_soft_reset(dev);
  
          if(rslt == BME280_OK)
          {
              rslt = reload_device_settings(&settings, dev);
          }
      }
  
      return rslt;
  }
  
  /*!
   * @brief This internal API reloads the already existing device settings in
   * the sensor after soft reset.
   */
  static int8_t reload_device_settings(const struct bme280_settings *settings, struct bme280_dev *dev)
  {
      int8_t rslt;
  
      rslt = set_osr_settings(BME280_ALL_SETTINGS_SEL, settings, dev);
  
      if(rslt == BME280_OK)
      {
          rslt = set_filter_standby_settings(BME280_ALL_SETTINGS_SEL, settings, dev);
      }
  
      return rslt;
  }
  
  #ifdef BME280_FLOAT_ENABLE
  
  /*!
   * @brief This internal API is used to compensate the raw temperature data and
   * return the compensated temperature data in double data type.
   */
  static double compensate_temperature(const struct bme280_uncomp_data *uncomp_data, struct bme280_calib_data *calib_data)
  {
      double var1;
      double var2;
      double temperature;
      double temperature_min = -40;
      double temperature_max = 85;
  
      var1 = ((double)uncomp_data->temperature) / 16384.0 - ((double)calib_data->dig_t1) / 1024.0;
      var1 = var1 * ((double)calib_data->dig_t2);
      var2 = (((double)uncomp_data->temperature) / 131072.0 - ((double)calib_data->dig_t1) / 8192.0);
      var2 = (var2 * var2) * ((double)calib_data->dig_t3);
      calib_data->t_fine = (int32_t)(var1 + var2);
      temperature = (var1 + var2) / 5120.0;
  
      if(temperature < temperature_min)
      {
          temperature = temperature_min;
      } else if(temperature > temperature_max)
      {
          temperature = temperature_max;
      }
  
      return temperature;
  }
  
  /*!
   * @brief This internal API is used to compensate the raw pressure data and
   * return the compensated pressure data in double data type.
   */
  static double compensate_pressure(const struct bme280_uncomp_data *uncomp_data,
                                    const struct bme280_calib_data *calib_data)
  {
      double var1;
      double var2;
      double var3;
      double pressure;
      double pressure_min = 30000.0;
      double pressure_max = 110000.0;
  
      var1 = ((double)calib_data->t_fine / 2.0) - 64000.0;
      var2 = var1 * var1 * ((double)calib_data->dig_p6) / 32768.0;
      var2 = var2 + var1 * ((double)calib_data->dig_p5) * 2.0;
      var2 = (var2 / 4.0) + (((double)calib_data->dig_p4) * 65536.0);
      var3 = ((double)calib_data->dig_p3) * var1 * var1 / 524288.0;
      var1 = (var3 + ((double)calib_data->dig_p2) * var1) / 524288.0;
      var1 = (1.0 + var1 / 32768.0) * ((double)calib_data->dig_p1);
  
      /* avoid exception caused by division by zero */
      if(var1 > (0.0))
      {
          pressure = 1048576.0 - (double)uncomp_data->pressure;
          pressure = (pressure - (var2 / 4096.0)) * 6250.0 / var1;
          var1 = ((double)calib_data->dig_p9) * pressure * pressure / 2147483648.0;
          var2 = pressure * ((double)calib_data->dig_p8) / 32768.0;
          pressure = pressure + (var1 + var2 + ((double)calib_data->dig_p7)) / 16.0;
  
          if(pressure < pressure_min)
          {
              pressure = pressure_min;
          } else if(pressure > pressure_max)
          {
              pressure = pressure_max;
          }
      } else /* Invalid case */
      {
          pressure = pressure_min;
      }
  
      return pressure;
  }
  
  /*!
   * @brief This internal API is used to compensate the raw humidity data and
   * return the compensated humidity data in double data type.
   */
  static double compensate_humidity(const struct bme280_uncomp_data *uncomp_data,
                                    const struct bme280_calib_data *calib_data)
  {
      double humidity;
      double humidity_min = 0.0;
      double humidity_max = 100.0;
      double var1;
      double var2;
      double var3;
      double var4;
      double var5;
      double var6;
  
      var1 = ((double)calib_data->t_fine) - 76800.0;
      var2 = (((double)calib_data->dig_h4) * 64.0 + (((double)calib_data->dig_h5) / 16384.0) * var1);
      var3 = uncomp_data->humidity - var2;
      var4 = ((double)calib_data->dig_h2) / 65536.0;
      var5 = (1.0 + (((double)calib_data->dig_h3) / 67108864.0) * var1);
      var6 = 1.0 + (((double)calib_data->dig_h6) / 67108864.0) * var1 * var5;
      var6 = var3 * var4 * (var5 * var6);
      humidity = var6 * (1.0 - ((double)calib_data->dig_h1) * var6 / 524288.0);
  
      if(humidity > humidity_max)
      {
          humidity = humidity_max;
      } else if(humidity < humidity_min)
      {
          humidity = humidity_min;
      }
  
      return humidity;
  }
  
  #else
  
  /*!
   * @brief This internal API is used to compensate the raw temperature data and
   * return the compensated temperature data in integer data type.
   */
  static int32_t compensate_temperature(const struct bme280_uncomp_data *uncomp_data,
                                        struct bme280_calib_data *calib_data)
  {
      int32_t var1;
      int32_t var2;
      int32_t temperature;
      int32_t temperature_min = -4000;
      int32_t temperature_max = 8500;
  
      var1 = (int32_t)((uncomp_data->temperature / 8) - ((int32_t)calib_data->dig_t1 * 2));
      var1 = (var1 * ((int32_t)calib_data->dig_t2)) / 2048;
      var2 = (int32_t)((uncomp_data->temperature / 16) - ((int32_t)calib_data->dig_t1));
      var2 = (((var2 * var2) / 4096) * ((int32_t)calib_data->dig_t3)) / 16384;
      calib_data->t_fine = var1 + var2;
      temperature = (calib_data->t_fine * 5 + 128) / 256;
  
      if(temperature < temperature_min)
      {
          temperature = temperature_min;
      } else if(temperature > temperature_max)
      {
          temperature = temperature_max;
      }
  
      return temperature;
  }
  #ifndef BME280_32BIT_ENABLE /* 64 bit compensation for pressure data */
  
  /*!
   * @brief This internal API is used to compensate the raw pressure data and
   * return the compensated pressure data in integer data type with higher
   * accuracy.
   */
  static uint32_t compensate_pressure(const struct bme280_uncomp_data *uncomp_data,
                                      const struct bme280_calib_data *calib_data)
  {
      int64_t var1;
      int64_t var2;
      int64_t var3;
      int64_t var4;
      uint32_t pressure;
      uint32_t pressure_min = 3000000;
      uint32_t pressure_max = 11000000;
  
      var1 = ((int64_t)calib_data->t_fine) - 128000;
      var2 = var1 * var1 * (int64_t)calib_data->dig_p6;
      var2 = var2 + ((var1 * (int64_t)calib_data->dig_p5) * 131072);
      var2 = var2 + (((int64_t)calib_data->dig_p4) * 34359738368);
      var1 = ((var1 * var1 * (int64_t)calib_data->dig_p3) / 256) + ((var1 * ((int64_t)calib_data->dig_p2) * 4096));
      var3 = ((int64_t)1) * 140737488355328;
      var1 = (var3 + var1) * ((int64_t)calib_data->dig_p1) / 8589934592;
  
      /* To avoid divide by zero exception */
      if(var1 != 0)
      {
          var4 = 1048576 - uncomp_data->pressure;
          var4 = (((var4 * INT64_C(2147483648)) - var2) * 3125) / var1;
          var1 = (((int64_t)calib_data->dig_p9) * (var4 / 8192) * (var4 / 8192)) / 33554432;
          var2 = (((int64_t)calib_data->dig_p8) * var4) / 524288;
          var4 = ((var4 + var1 + var2) / 256) + (((int64_t)calib_data->dig_p7) * 16);
          pressure = (uint32_t)(((var4 / 2) * 100) / 128);
  
          if(pressure < pressure_min)
          {
              pressure = pressure_min;
          } else if(pressure > pressure_max)
          {
              pressure = pressure_max;
          }
      } else
      {
          pressure = pressure_min;
      }
  
      return pressure;
  }
  #else                       /* 32 bit compensation for pressure data */
  
  /*!
   * @brief This internal API is used to compensate the raw pressure data and
   * return the compensated pressure data in integer data type.
   */
  static uint32_t compensate_pressure(const struct bme280_uncomp_data *uncomp_data,
                                      const struct bme280_calib_data *calib_data)
  {
      int32_t var1;
      int32_t var2;
      int32_t var3;
      int32_t var4;
      uint32_t var5;
      uint32_t pressure;
      uint32_t pressure_min = 30000;
      uint32_t pressure_max = 110000;
  
      var1 = (((int32_t)calib_data->t_fine) / 2) - (int32_t)64000;
      var2 = (((var1 / 4) * (var1 / 4)) / 2048) * ((int32_t)calib_data->dig_p6);
      var2 = var2 + ((var1 * ((int32_t)calib_data->dig_p5)) * 2);
      var2 = (var2 / 4) + (((int32_t)calib_data->dig_p4) * 65536);
      var3 = (calib_data->dig_p3 * (((var1 / 4) * (var1 / 4)) / 8192)) / 8;
      var4 = (((int32_t)calib_data->dig_p2) * var1) / 2;
      var1 = (var3 + var4) / 262144;
      var1 = (((32768 + var1)) * ((int32_t)calib_data->dig_p1)) / 32768;
  
      /* avoid exception caused by division by zero */
      if(var1)
      {
          var5 = (uint32_t)((uint32_t)1048576) - uncomp_data->pressure;
          pressure = ((uint32_t)(var5 - (uint32_t)(var2 / 4096))) * 3125;
  
          if(pressure < 0x80000000)
          {
              pressure = (pressure << 1) / ((uint32_t)var1);
          } else
          {
              pressure = (pressure / (uint32_t)var1) * 2;
          }
  
          var1 = (((int32_t)calib_data->dig_p9) * ((int32_t)(((pressure / 8) * (pressure / 8)) / 8192))) / 4096;
          var2 = (((int32_t)(pressure / 4)) * ((int32_t)calib_data->dig_p8)) / 8192;
          pressure = (uint32_t)((int32_t)pressure + ((var1 + var2 + calib_data->dig_p7) / 16));
  
          if(pressure < pressure_min)
          {
              pressure = pressure_min;
          } else if(pressure > pressure_max)
          {
              pressure = pressure_max;
          }
      } else
      {
          pressure = pressure_min;
      }
  
      return pressure;
  }
  #endif
  
  /*!
   * @brief This internal API is used to compensate the raw humidity data and
   * return the compensated humidity data in integer data type.
   */
  static uint32_t compensate_humidity(const struct bme280_uncomp_data *uncomp_data,
                                      const struct bme280_calib_data *calib_data)
  {
      int32_t var1;
      int32_t var2;
      int32_t var3;
      int32_t var4;
      int32_t var5;
      uint32_t humidity;
      uint32_t humidity_max = 102400;
  
      var1 = calib_data->t_fine - ((int32_t)76800);
      var2 = (int32_t)(uncomp_data->humidity * 16384);
      var3 = (int32_t)(((int32_t)calib_data->dig_h4) * 1048576);
      var4 = ((int32_t)calib_data->dig_h5) * var1;
      var5 = (((var2 - var3) - var4) + (int32_t)16384) / 32768;
      var2 = (var1 * ((int32_t)calib_data->dig_h6)) / 1024;
      var3 = (var1 * ((int32_t)calib_data->dig_h3)) / 2048;
      var4 = ((var2 * (var3 + (int32_t)32768)) / 1024) + (int32_t)2097152;
      var2 = ((var4 * ((int32_t)calib_data->dig_h2)) + 8192) / 16384;
      var3 = var5 * var2;
      var4 = ((var3 / 32768) * (var3 / 32768)) / 128;
      var5 = var3 - ((var4 * ((int32_t)calib_data->dig_h1)) / 16);
      var5 = (var5 < 0 ? 0 : var5);
      var5 = (var5 > 419430400 ? 419430400 : var5);
      humidity = (uint32_t)(var5 / 4096);
  
      if(humidity > humidity_max)
      {
          humidity = humidity_max;
      }
  
      return humidity;
  }
  #endif
  
  /*!
   * @brief This internal API reads the calibration data from the sensor, parse
   * it and store in the device structure.
   */
  static int8_t get_calib_data(struct bme280_dev *dev)
  {
      int8_t rslt;
      uint8_t reg_addr = BME280_TEMP_PRESS_CALIB_DATA_ADDR;
  
      /* Array to store calibration data */
      uint8_t calib_data[BME280_TEMP_PRESS_CALIB_DATA_LEN] = {0};
  
      /* Read the calibration data from the sensor */
      rslt = bme280_get_regs(reg_addr, calib_data, BME280_TEMP_PRESS_CALIB_DATA_LEN, dev);
  
      if(rslt == BME280_OK)
      {
          /* Parse temperature and pressure calibration data and store
           * it in device structure
           */
          parse_temp_press_calib_data(calib_data, dev);
          reg_addr = BME280_HUMIDITY_CALIB_DATA_ADDR;
  
          /* Read the humidity calibration data from the sensor */
          rslt = bme280_get_regs(reg_addr, calib_data, BME280_HUMIDITY_CALIB_DATA_LEN, dev);
  
          if(rslt == BME280_OK)
          {
              /* Parse humidity calibration data and store it in
               * device structure
               */
              parse_humidity_calib_data(calib_data, dev);
          }
      }
  
      return rslt;
  }
  
  /*!
   * @brief This internal API interleaves the register address between the
   * register data buffer for burst write operation.
   */
  static void interleave_reg_addr(const uint8_t *reg_addr, uint8_t *temp_buff, const uint8_t *reg_data, uint8_t len)
  {
      uint8_t index;
  
      for(index = 1; index < len; index++)
      {
          temp_buff[(index * 2) - 1] = reg_addr[index];
          temp_buff[index * 2] = reg_data[index];
      }
  }
  
  /*!
   *  @brief This internal API is used to parse the temperature and
   *  pressure calibration data and store it in device structure.
   */
  static void parse_temp_press_calib_data(const uint8_t *reg_data, struct bme280_dev *dev)
  {
      struct bme280_calib_data *calib_data = &dev->calib_data;
  
      calib_data->dig_t1 = BME280_CONCAT_BYTES(reg_data[1], reg_data[0]);
      calib_data->dig_t2 = (int16_t)BME280_CONCAT_BYTES(reg_data[3], reg_data[2]);
      calib_data->dig_t3 = (int16_t)BME280_CONCAT_BYTES(reg_data[5], reg_data[4]);
      calib_data->dig_p1 = BME280_CONCAT_BYTES(reg_data[7], reg_data[6]);
      calib_data->dig_p2 = (int16_t)BME280_CONCAT_BYTES(reg_data[9], reg_data[8]);
      calib_data->dig_p3 = (int16_t)BME280_CONCAT_BYTES(reg_data[11], reg_data[10]);
      calib_data->dig_p4 = (int16_t)BME280_CONCAT_BYTES(reg_data[13], reg_data[12]);
      calib_data->dig_p5 = (int16_t)BME280_CONCAT_BYTES(reg_data[15], reg_data[14]);
      calib_data->dig_p6 = (int16_t)BME280_CONCAT_BYTES(reg_data[17], reg_data[16]);
      calib_data->dig_p7 = (int16_t)BME280_CONCAT_BYTES(reg_data[19], reg_data[18]);
      calib_data->dig_p8 = (int16_t)BME280_CONCAT_BYTES(reg_data[21], reg_data[20]);
      calib_data->dig_p9 = (int16_t)BME280_CONCAT_BYTES(reg_data[23], reg_data[22]);
      calib_data->dig_h1 = reg_data[25];
  }
  
  /*!
   *  @brief This internal API is used to parse the humidity calibration data
   *  and store it in device structure.
   */
  static void parse_humidity_calib_data(const uint8_t *reg_data, struct bme280_dev *dev)
  {
      struct bme280_calib_data *calib_data = &dev->calib_data;
      int16_t dig_h4_lsb;
      int16_t dig_h4_msb;
      int16_t dig_h5_lsb;
      int16_t dig_h5_msb;
  
      calib_data->dig_h2 = (int16_t)BME280_CONCAT_BYTES(reg_data[1], reg_data[0]);
      calib_data->dig_h3 = reg_data[2];
      dig_h4_msb = (int16_t)(int8_t)reg_data[3] * 16;
      dig_h4_lsb = (int16_t)(reg_data[4] & 0x0F);
      calib_data->dig_h4 = dig_h4_msb | dig_h4_lsb;
      dig_h5_msb = (int16_t)(int8_t)reg_data[5] * 16;
      dig_h5_lsb = (int16_t)(reg_data[4] >> 4);
      calib_data->dig_h5 = dig_h5_msb | dig_h5_lsb;
      calib_data->dig_h6 = (int8_t)reg_data[6];
  }
  
  /*!
   * @brief This internal API is used to identify the settings which the user
   * wants to modify in the sensor.
   */
  static uint8_t are_settings_changed(uint8_t sub_settings, uint8_t desired_settings)
  {
      uint8_t settings_changed = FALSE;
  
      if(sub_settings & desired_settings)
      {
          /* User wants to modify this particular settings */
          settings_changed = TRUE;
      } else
      {
          /* User don't want to modify this particular settings */
          settings_changed = FALSE;
      }
  
      return settings_changed;
  }
  
  /*!
   * @brief This internal API is used to validate the device structure pointer for
   * null conditions.
   */
  static int8_t null_ptr_check(const struct bme280_dev *dev)
  {
      int8_t rslt;
  
      if((dev == NULL) || (dev->read == NULL) || (dev->write == NULL) || (dev->delay_us == NULL))
      {
          /* Device structure pointer is not valid */
          rslt = BME280_E_NULL_PTR;
      } else
      {
          /* Device structure is fine */
          rslt = BME280_OK;
      }
  
      return rslt;
  }
  