barometer: Add barometer driver for BMP280 in EC

BMP280 driver API is designed to work with motion
sensor task. The sensor sampling parameters are
configured optimally for handheld device in accordance
with BMP280 spec recommendation.

BUG=None
BRANCH=master
TEST=Tested on amenia; with appropriate .odr in board file
     test command "accelread 4" returns raw pressure
     value in Pa; accelinfo on 4000 shows Pa value.

Change-Id: I3f4c0c33a77dd317aa1425624d3cc7f4ec6b45a1
Signed-off-by: Divya Sasidharan <divya.s.sasidharan@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/351660
Commit-Ready: Divya S Sasidharan <divya.s.sasidharan@intel.com>
Tested-by: Divya S Sasidharan <divya.s.sasidharan@intel.com>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>

3 files changed, 591 insertions, 0 deletions

diff --git a/driver/baro_bmp280.c b/driver/baro_bmp280.c
new file mode 100644
index 0000000000..b568407265
--- /dev/null
+++ b/driver/baro_bmp280.c
@@ -0,0 +1,383 @@
+/* Copyright 2016 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+/*
+****************************************************************************
+* Copyright (C) 2012 - 2015 Bosch Sensortec GmbH
+*
+* File : bmp280.h
+*
+* Date : 2015/03/27
+*
+* Revision : 2.0.4(Pressure and Temperature compensation code revision is 1.1)
+*
+* Usage: Sensor Driver for BMP280 sensor
+*
+****************************************************************************
+*
+* \section License
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are met:
+*
+*   Redistributions of source code must retain the above copyright
+*   notice, this list of conditions and the following disclaimer.
+*
+*   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.
+*
+*   Neither the name of the copyright holder nor the names of the
+*   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 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
+*
+* The information provided is believed to be accurate and reliable.
+* The copyright holder assumes no responsibility
+* for the consequences of use
+* of such information nor for any infringement of patents or
+* other rights of third parties which may result from its use.
+* No license is granted by implication or otherwise under any patent or
+* patent rights of the copyright holder.
+**************************************************************************/
+#include "accelgyro.h"
+#include "common.h"
+#include "console.h"
+#include "driver/baro_bmp280.h"
+#include "i2c.h"
+#include "timer.h"
+
+#define CPRINTF(format, args...) cprintf(CC_ACCEL, format, ## args)
+#define CPRINTS(format, args...) cprints(CC_ACCEL, format, ## args)
+
+static const int standby_durn[] = {1, 63, 125, 250, 500, 1000, 2000, 4000};
+
+static inline int raw_read8(const int port, const int addr, const uint8_t reg,
+					 int *data_ptr)
+{
+	return i2c_read8(port, addr, reg, data_ptr);
+}
+
+/*
+ * Read n bytes from barometer.
+ */
+static inline int raw_read_n(const int port, const int addr, const uint8_t reg,
+		uint8_t *data_ptr, const int len)
+{
+	int rv;
+
+	i2c_lock(port, 1);
+	rv = i2c_xfer(port, addr, &reg, 1,
+			data_ptr, len, I2C_XFER_SINGLE);
+	i2c_lock(port, 0);
+	return rv;
+}
+
+/*
+ * Write 8bit register from accelerometer.
+ */
+static inline int raw_write8(const int port, const int addr, const uint8_t reg,
+		int data)
+{
+	return i2c_write8(port, addr, reg, data);
+}
+
+
+/*
+ * This function is used to get calibration parameters used for
+ * calculation in the registers
+ *
+ *  parameter | Register address |   bit
+ *------------|------------------|----------------
+ *	dig_T1    |  0x88 and 0x89   | from 0 : 7 to 8: 15
+ *	dig_T2    |  0x8A and 0x8B   | from 0 : 7 to 8: 15
+ *	dig_T3    |  0x8C and 0x8D   | from 0 : 7 to 8: 15
+ *	dig_P1    |  0x8E and 0x8F   | from 0 : 7 to 8: 15
+ *	dig_P2    |  0x90 and 0x91   | from 0 : 7 to 8: 15
+ *	dig_P3    |  0x92 and 0x93   | from 0 : 7 to 8: 15
+ *	dig_P4    |  0x94 and 0x95   | from 0 : 7 to 8: 15
+ *	dig_P5    |  0x96 and 0x97   | from 0 : 7 to 8: 15
+ *	dig_P6    |  0x98 and 0x99   | from 0 : 7 to 8: 15
+ *	dig_P7    |  0x9A and 0x9B   | from 0 : 7 to 8: 15
+ *	dig_P8    |  0x9C and 0x9D   | from 0 : 7 to 8: 15
+ *	dig_P9    |  0x9E and 0x9F   | from 0 : 7 to 8: 15
+ *
+ *	@return results of bus communication function
+ *	@retval 0 -> Success
+ *
+ */
+
+static int bmp280_get_calib_param(const struct motion_sensor_t *s)
+{
+	int ret;
+
+	uint8_t a_data_u8[BMP280_CALIB_DATA_SIZE] = {0};
+	struct bmp280_drv_data_t *data = BMP280_GET_DATA(s);
+
+	ret = raw_read_n(s->port, s->addr,
+			BMP280_TEMPERATURE_CALIB_DIG_T1_LSB_REG,
+			a_data_u8, BMP280_CALIB_DATA_SIZE);
+
+	if (ret)
+		return ret;
+
+	/* read calibration values*/
+	data->calib_param.dig_T1 = (a_data_u8[1] << 8) | a_data_u8[0];
+	data->calib_param.dig_T2 = (a_data_u8[3] << 8  | a_data_u8[2]);
+	data->calib_param.dig_T3 = (a_data_u8[5] << 8) | a_data_u8[4];
+
+	data->calib_param.dig_P1 = (a_data_u8[7] << 8) | a_data_u8[6];
+	data->calib_param.dig_P2 = (a_data_u8[9] << 8) | a_data_u8[8];
+	data->calib_param.dig_P3 = (a_data_u8[11] << 8) | a_data_u8[10];
+	data->calib_param.dig_P4 = (a_data_u8[13] << 8) | a_data_u8[12];
+	data->calib_param.dig_P5 = (a_data_u8[15] << 8) | a_data_u8[14];
+	data->calib_param.dig_P6 = (a_data_u8[17] << 8) | a_data_u8[16];
+	data->calib_param.dig_P7 = (a_data_u8[19] << 8) | a_data_u8[18];
+	data->calib_param.dig_P8 = (a_data_u8[21] << 8) | a_data_u8[20];
+	data->calib_param.dig_P9 = (a_data_u8[23] << 8) | a_data_u8[22];
+
+	return EC_SUCCESS;
+}
+
+static int bmp280_read_uncomp_pressure(const struct motion_sensor_t *s,
+					int *uncomp_pres)
+{
+	int ret;
+	uint8_t a_data_u8[BMP280_PRESSURE_DATA_SIZE] = {0};
+
+	ret = raw_read_n(s->port, s->addr,
+			BMP280_PRESSURE_MSB_REG,
+			a_data_u8, BMP280_PRESSURE_DATA_SIZE);
+
+	if (ret)
+		return ret;
+
+	*uncomp_pres = (int32_t)((a_data_u8[0] << 12) |
+		     (a_data_u8[1] << 4) |
+		     (a_data_u8[2] >> 4));
+
+	return EC_SUCCESS;
+}
+
+/*
+ * Reads actual pressure from uncompensated pressure
+ * and returns the value in Pascal(Pa)
+ * @note Output value of "96386" equals 96386 Pa =
+ * 963.86 hPa = 963.86 millibar
+ *
+ * Algorithm from BMP280 Datasheet Rev 1.15 Section 8.2
+ *
+ */
+static int bmp280_compensate_pressure(const struct motion_sensor_t *s,
+					int uncomp_pressure)
+{
+	int var1, var2;
+	uint32_t p;
+	struct bmp280_drv_data_t *data = BMP280_GET_DATA(s);
+
+	/* calculate x1 */
+	var1 = (((int32_t)data->calib_param.t_fine)
+		>> 1) - 64000;
+	/* calculate x2 */
+	var2 = (((var1 >> 2) * (var1 >> 2)) >> 11)
+		* ((int32_t)data->calib_param.dig_P6);
+	var2 = var2 + ((var1 * ((int32_t)data->calib_param.dig_P5)) << 1);
+	var2 = (var2 >> 2) + (((int32_t)data->calib_param.dig_P4) << 16);
+	/* calculate x1 */
+	var1 = (((data->calib_param.dig_P3 *
+		(((var1 >> 2) * (var1 >> 2)) >> 13)) >> 3) +
+		((((int32_t)data->calib_param.dig_P2) * var1) >> 1)) >> 18;
+	var1 = ((((32768 + var1)) *
+		((int32_t)data->calib_param.dig_P1)) >> 15);
+
+	/* Avoid exception caused by division by zero */
+	if (!var1)
+		return 0;
+
+	/* calculate pressure */
+	p = (((uint32_t)((1048576) - uncomp_pressure) -
+		(var2 >> 12))) * 3125;
+
+	/* check overflow */
+	if (p < 0x80000000)
+		p = (p << 1) / ((uint32_t)var1);
+	else
+		p = (p / (uint32_t)var1) << 1;
+
+	/* calculate x1 */
+	var1 = (((int32_t)data->calib_param.dig_P9) *
+		((int32_t)(((p >> 3) * (p >> 3)) >> 13))) >> 12;
+	/* calculate x2 */
+	var2 = (((int32_t)(p >> 2)) *
+		((int32_t)data->calib_param.dig_P8)) >> 13;
+	/* calculate true pressure */
+	return (uint32_t)((int32_t)p + ((var1 + var2 +
+		data->calib_param.dig_P7) >> 4));
+}
+
+/*
+ * Set the standby duration
+ * standby_durn: The standby duration time value.
+ *  value     |  standby duration
+ *  ----------|--------------------
+ *    0x00    | 1_MS
+ *    0x01    | 63_MS
+ *    0x02    | 125_MS
+ *    0x03    | 250_MS
+ *    0x04    | 500_MS
+ *    0x05    | 1000_MS
+ *    0x06    | 2000_MS
+ *    0x07    | 4000_MS
+ */
+static int bmp280_set_standby_durn(const struct motion_sensor_t *s,
+				uint8_t durn)
+{
+	int ret, val;
+	struct bmp280_drv_data_t *data = BMP280_GET_DATA(s);
+
+	ret = raw_read8(s->port, s->addr,
+			BMP280_CONFIG_REG, &val);
+
+	if (ret == EC_SUCCESS) {
+		val = (val & 0xE0) | ((durn << 5) & 0xE0);
+		/* write the standby duration*/
+		ret = raw_write8(s->port, s->addr,
+			   BMP280_CONFIG_REG, val);
+	}
+
+	data->rate = standby_durn[durn] + BMP280_COMPUTE_TIME;
+	return ret;
+}
+
+static int bmp280_set_power_mode(const struct motion_sensor_t *s,
+				uint8_t power_mode)
+{
+	int val;
+
+	val = (BMP280_OVERSAMP_TEMP << 5) +
+		(BMP280_OVERSAMP_PRES << 2) + power_mode;
+
+	return raw_write8(s->port, s->addr, BMP280_CTRL_MEAS_REG, val);
+}
+
+/*
+ * bmp280_init() - Used to initialize barometer with default config
+ *
+ * @return results of bus communication function
+ * @retval 0 -> Success
+ */
+
+static int bmp280_init(const struct motion_sensor_t *s)
+{
+	int val, ret;
+
+	if (!s)
+		return EC_ERROR_INVAL;
+
+	/* Read chip id */
+	ret = raw_read8(s->port, s->addr,
+				BMP280_CHIP_ID_REG, &val);
+	if (ret)
+		return ret;
+
+	if (val != BMP280_CHIP_ID)
+		return EC_ERROR_INVAL;
+
+	/* set power mode */
+	ret = bmp280_set_power_mode(s, BMP280_SLEEP_MODE);
+	if (ret)
+		return ret;
+
+	/* Read bmp280 calibration parameter */
+	return bmp280_get_calib_param(s);
+}
+
+static int bmp280_read(const struct motion_sensor_t *s, vector_3_t v)
+{
+	int ret, pres;
+	struct bmp280_drv_data_t *data = BMP280_GET_DATA(s);
+
+	/* Sensor in sleep mode */
+	if (!data->rate)
+		return EC_ERROR_INVAL;
+
+	ret = bmp280_read_uncomp_pressure(s, &pres);
+
+	if (ret)
+		return ret;
+
+	v[0] = bmp280_compensate_pressure(s, pres);
+	v[1] = v[2] = 0;
+
+	return EC_SUCCESS;
+}
+
+/* Set desired standby duration in ms */
+static int bmp280_set_data_rate(const struct motion_sensor_t *s, int rate,
+							int roundup)
+{
+	struct bmp280_drv_data_t *data = BMP280_GET_DATA(s);
+	int durn, i, ret;
+
+	if (rate < 0)
+		return EC_ERROR_INVAL;
+
+	if (!rate) {
+		/* Set to sleep mode */
+		data->rate = 0;
+		return bmp280_set_power_mode(s, BMP280_SLEEP_MODE);
+	}
+
+	/* reset power mode, waking from sleep */
+	if (!data->rate) {
+		ret = bmp280_set_power_mode(s, BMP280_NORMAL_MODE);
+		if (ret)
+			return ret;
+	}
+
+	durn = BMP280_STANDBY_CNT-1;
+	for (i = 0; i < BMP280_STANDBY_CNT-1; i++) {
+		if (rate == (standby_durn[i] + BMP280_COMPUTE_TIME) ||
+			rate < (standby_durn[i] + BMP280_COMPUTE_TIME)) {
+			durn = i;
+			break;
+		} else if (rate > (standby_durn[i] + BMP280_COMPUTE_TIME) &&
+			rate < (standby_durn[i+1] + BMP280_COMPUTE_TIME)) {
+			durn = roundup ? i+1 : i;
+			break;
+		}
+	}
+	return bmp280_set_standby_durn(s, durn);
+}
+
+static int bmp280_get_data_rate(const struct motion_sensor_t *s)
+{
+	struct bmp280_drv_data_t *data = BMP280_GET_DATA(s);
+
+	return data->rate;
+}
+
+struct bmp280_drv_data_t bmp280_drv_data;
+
+const struct accelgyro_drv bmp280_drv = {
+	.init = bmp280_init,
+	.read = bmp280_read,
+	.set_data_rate = bmp280_set_data_rate,
+	.get_data_rate = bmp280_get_data_rate,
+};
diff --git a/driver/baro_bmp280.h b/driver/baro_bmp280.h
new file mode 100644
index 0000000000..586ed6677b
--- /dev/null
+++ b/driver/baro_bmp280.h
@@ -0,0 +1,205 @@
+/* Copyright 2016 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+/** \mainpage
+*
+****************************************************************************
+* Copyright (C) 2012 - 2015 Bosch Sensortec GmbH
+*
+* File : bmp280.h
+*
+* Date : 2015/03/27
+*
+* Revision : 2.0.4(Pressure and Temperature compensation code revision is 1.1)
+*
+* Usage: Sensor Driver for BMP280 sensor
+*
+****************************************************************************
+*
+* \section License
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are met:
+*
+*   Redistributions of source code must retain the above copyright
+*   notice, this list of conditions and the following disclaimer.
+*
+*   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.
+*
+*   Neither the name of the copyright holder nor the names of the
+*   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 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
+*
+* The information provided is believed to be accurate and reliable.
+* The copyright holder assumes no responsibility
+* for the consequences of use
+* of such information nor for any infringement of patents or
+* other rights of third parties which may result from its use.
+* No license is granted by implication or otherwise under any patent or
+* patent rights of the copyright holder.
+**************************************************************************/
+/* BMP280 pressure and temperature module for Chrome EC */
+
+#ifndef __CROS_EC_BARO_BMP280_H
+#define __CROS_EC_BARO_BMP280_H
+
+/*
+ * The addr field of barometer_sensor for I2C:
+ *
+ * +-------------------------------+---+
+ * |    7 bit i2c address          | 0 |
+ * +-------------------------------+---+
+ */
+
+/*
+ * Bit 1 of 7-bit address: 0 - If SDO is connected to GND
+ * Bit 1 of 7-bit address: 1 - If SDO is connected to Vddio
+ */
+#define BMP280_I2C_ADDRESS1		((0x76) << 1)
+#define BMP280_I2C_ADDRESS2		((0x77) << 1)
+/*
+ *     CHIP ID
+ */
+#define BMP280_CHIP_ID			0x58
+/************************************************/
+/*	CALIBRATION PARAMETERS DEFINITION       */
+/************************************************/
+
+#define BMP280_TEMPERATURE_CALIB_DIG_T1_LSB_REG	0x88
+
+/************************************************/
+/*	REGISTER ADDRESS DEFINITION             */
+/************************************************/
+#define BMP280_CHIP_ID_REG		     0xD0
+#define BMP280_RST_REG                       0xE0  /*Softreset Register */
+#define BMP280_STAT_REG                      0xF3  /*Status Register */
+#define BMP280_CTRL_MEAS_REG                 0xF4  /*Ctrl Measure Register */
+#define BMP280_CONFIG_REG                    0xF5  /*Configuration Register */
+#define BMP280_PRESSURE_MSB_REG              0xF7  /*Pressure MSB Register */
+#define BMP280_PRESSURE_LSB_REG              0xF8  /*Pressure LSB Register */
+#define BMP280_PRESSURE_XLSB_REG             0xF9  /*Pressure XLSB Register */
+/************************************************/
+/*	POWER MODE DEFINITION                   */
+/************************************************/
+/* Sensor Specific constants */
+#define BMP280_SLEEP_MODE                    0x00
+#define BMP280_FORCED_MODE                   0x01
+#define BMP280_NORMAL_MODE                   0x03
+#define BMP280_SOFT_RESET_CODE               0xB6
+/************************************************/
+/*	STANDBY TIME DEFINITION                 */
+/************************************************/
+#define BMP280_STANDBY_TIME_1_MS              0x00
+#define BMP280_STANDBY_TIME_63_MS             0x01
+#define BMP280_STANDBY_TIME_125_MS            0x02
+#define BMP280_STANDBY_TIME_250_MS            0x03
+#define BMP280_STANDBY_TIME_500_MS            0x04
+#define BMP280_STANDBY_TIME_1000_MS           0x05
+#define BMP280_STANDBY_TIME_2000_MS           0x06
+#define BMP280_STANDBY_TIME_4000_MS           0x07
+/************************************************/
+/*	OVERSAMPLING DEFINITION                 */
+/************************************************/
+#define BMP280_OVERSAMP_SKIPPED          0x00
+#define BMP280_OVERSAMP_1X               0x01
+#define BMP280_OVERSAMP_2X               0x02
+#define BMP280_OVERSAMP_4X               0x03
+#define BMP280_OVERSAMP_8X               0x04
+#define BMP280_OVERSAMP_16X              0x05
+/************************************************/
+/*	DEFINITIONS FOR ARRAY SIZE OF DATA      */
+/************************************************/
+#define	BMP280_PRESSURE_DATA_SIZE	3
+#define	BMP280_DATA_FRAME_SIZE		6
+#define	BMP280_CALIB_DATA_SIZE		24
+/*******************************************************/
+/*         SAMPLING PERIOD COMPUTATION CONSTANT	       */
+/*******************************************************/
+#define BMP280_STANDBY_CNT		8
+#define T_INIT_MAX			(20) /* (20/16 = 1.25ms) */
+#define T_MEASURE_PER_OSRS_MAX		(37) /* (37/16 = 2.31ms) */
+#define T_SETUP_PRESSURE_MAX		(10) /* (10/16 = 0.62ms) */
+
+/*
+ * This is the measurement time required for pressure and temp
+ */
+#define BMP280_COMPUTE_TIME \
+	((T_INIT_MAX + T_MEASURE_PER_OSRS_MAX * \
+	(((1 << BMP280_OVERSAMP_TEMP) >> 1) + \
+	((1 << BMP280_OVERSAMP_PRES) >> 1)) + \
+	(BMP280_OVERSAMP_PRES ? T_SETUP_PRESSURE_MAX : 0) + 15) / 16)
+
+/*
+ * These values are selected as per Bosch recommendation for
+ * standard handheld devices, with temp sensor not being used
+ */
+#define BMP280_OVERSAMP_PRES BMP280_OVERSAMP_4X
+#define BMP280_OVERSAMP_TEMP BMP280_OVERSAMP_SKIPPED
+/*******************************************************/
+/*             GET DRIVER DATA			       */
+/*******************************************************/
+#define BMP280_GET_DATA(_s) \
+	((struct bmp280_drv_data_t *)(_s)->drv_data)
+/**************************************************************/
+/*	STRUCTURE and ENUM DEFINITIONS                        */
+/**************************************************************/
+
+/*
+ * struct bmp280_calib_param_t - Holds all device specific
+ *                                calibration parameters
+ *
+ * @dig_T1 to dig_T3:   calibration Temp data
+ * @dig_P1 to dig_P9:   calibration Pressure data
+ * @t_fine:   calibration t_fine data
+ *
+ */
+struct bmp280_calib_param_t {
+	uint16_t dig_T1;
+	int16_t dig_T2;
+	int16_t dig_T3;
+	uint16_t dig_P1;
+	int16_t dig_P2;
+	int16_t dig_P3;
+	int16_t dig_P4;
+	int16_t dig_P5;
+	int16_t dig_P6;
+	int16_t dig_P7;
+	int16_t dig_P8;
+	int16_t dig_P9;
+
+	int32_t t_fine;
+};
+
+/*
+ * struct bmp280_t - This structure holds BMP280 initialization parameters
+ * @calib_param:          calibration data
+ * @rate:		  rate set
+ */
+struct bmp280_drv_data_t {
+
+	struct  bmp280_calib_param_t calib_param;
+	int	rate;
+};
+
+extern const struct accelgyro_drv bmp280_drv;
+extern struct bmp280_drv_data_t bmp280_drv_data;
+#endif
diff --git a/driver/build.mk b/driver/build.mk
index 1458874864..514de8cc50 100644
--- a/driver/build.mk
+++ b/driver/build.mk
@@ -22,6 +22,9 @@ driver-$(CONFIG_ALS_ISL29035)+=als_isl29035.o
 driver-$(CONFIG_ALS_OPT3001)+=als_opt3001.o
 driver-$(CONFIG_ALS_SI114X)+=als_si114x.o
 
+#Barometers
+driver-$(CONFIG_BARO_BMP280)+=baro_bmp280.o
+
 # Batteries
 driver-$(CONFIG_BATTERY_BQ20Z453)+=battery/bq20z453.o
 driver-$(CONFIG_BATTERY_BQ27541)+=battery/bq27541.o