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zephyr/drivers/sensor/bme680/bme680.c

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/* bme680.c - Driver for Bosch Sensortec's BME680 temperature, pressure,
* humidity and gas sensor
*
* https://www.bosch-sensortec.com/bst/products/all_products/bme680
*/
/*
* Copyright (c) 2018 Bosch Sensortec GmbH
*
* SPDX-License-Identifier: Apache-2.0
*/
#define DT_DRV_COMPAT bosch_bme680
#include "bme680.h"
#include <drivers/gpio.h>
#include <drivers/i2c.h>
#include <init.h>
#include <kernel.h>
#include <sys/byteorder.h>
#include <sys/__assert.h>
#include <drivers/sensor.h>
#include <logging/log.h>
LOG_MODULE_REGISTER(bme680, CONFIG_SENSOR_LOG_LEVEL);
static int bme680_reg_read(struct bme680_data *data, uint8_t start, uint8_t *buf,
int size)
{
return i2c_burst_read(data->i2c_master, data->i2c_slave_addr, start,
buf, size);
return 0;
}
static int bme680_reg_write(struct bme680_data *data, uint8_t reg, uint8_t val)
{
return i2c_reg_write_byte(data->i2c_master, data->i2c_slave_addr,
reg, val);
return 0;
}
static void bme680_calc_temp(struct bme680_data *data, uint32_t adc_temp)
{
int64_t var1, var2, var3;
var1 = ((int32_t)adc_temp >> 3) - ((int32_t)data->par_t1 << 1);
var2 = (var1 * (int32_t)data->par_t2) >> 11;
var3 = ((var1 >> 1) * (var1 >> 1)) >> 12;
var3 = ((var3) * ((int32_t)data->par_t3 << 4)) >> 14;
data->t_fine = var2 + var3;
data->calc_temp = ((data->t_fine * 5) + 128) >> 8;
}
static void bme680_calc_press(struct bme680_data *data, uint32_t adc_press)
{
int32_t var1, var2, var3, calc_press;
var1 = (((int32_t)data->t_fine) >> 1) - 64000;
var2 = ((((var1 >> 2) * (var1 >> 2)) >> 11) *
(int32_t)data->par_p6) >> 2;
var2 = var2 + ((var1 * (int32_t)data->par_p5) << 1);
var2 = (var2 >> 2) + ((int32_t)data->par_p4 << 16);
var1 = (((((var1 >> 2) * (var1 >> 2)) >> 13) *
((int32_t)data->par_p3 << 5)) >> 3)
+ (((int32_t)data->par_p2 * var1) >> 1);
var1 = var1 >> 18;
var1 = ((32768 + var1) * (int32_t)data->par_p1) >> 15;
calc_press = 1048576 - adc_press;
calc_press = (calc_press - (var2 >> 12)) * ((uint32_t)3125);
/* This max value is used to provide precedence to multiplication or
* division in the pressure calculation equation to achieve least
* loss of precision and avoiding overflows.
* i.e Comparing value, signed int 32bit (1 << 30)
*/
if (calc_press >= (int32_t)0x40000000) {
calc_press = ((calc_press / var1) << 1);
} else {
calc_press = ((calc_press << 1) / var1);
}
var1 = ((int32_t)data->par_p9 *
(int32_t)(((calc_press >> 3)
* (calc_press >> 3)) >> 13)) >> 12;
var2 = ((int32_t)(calc_press >> 2) * (int32_t)data->par_p8) >> 13;
var3 = ((int32_t)(calc_press >> 8) * (int32_t)(calc_press >> 8)
* (int32_t)(calc_press >> 8)
* (int32_t)data->par_p10) >> 17;
data->calc_press = calc_press
+ ((var1 + var2 + var3
+ ((int32_t)data->par_p7 << 7)) >> 4);
}
static void bme680_calc_humidity(struct bme680_data *data, uint16_t adc_humidity)
{
int32_t var1, var2_1, var2_2, var2, var3, var4, var5, var6;
int32_t temp_scaled, calc_hum;
temp_scaled = (((int32_t)data->t_fine * 5) + 128) >> 8;
var1 = (int32_t)(adc_humidity - ((int32_t)((int32_t)data->par_h1 * 16))) -
(((temp_scaled * (int32_t)data->par_h3)
/ ((int32_t)100)) >> 1);
var2_1 = (int32_t)data->par_h2;
var2_2 = ((temp_scaled * (int32_t)data->par_h4) / (int32_t)100)
+ (((temp_scaled * ((temp_scaled * (int32_t)data->par_h5)
/ ((int32_t)100))) >> 6) / ((int32_t)100))
+ (int32_t)(1 << 14);
var2 = (var2_1 * var2_2) >> 10;
var3 = var1 * var2;
var4 = (int32_t)data->par_h6 << 7;
var4 = ((var4) + ((temp_scaled * (int32_t)data->par_h7) /
((int32_t)100))) >> 4;
var5 = ((var3 >> 14) * (var3 >> 14)) >> 10;
var6 = (var4 * var5) >> 1;
calc_hum = (((var3 + var6) >> 10) * ((int32_t)1000)) >> 12;
if (calc_hum > 100000) { /* Cap at 100%rH */
calc_hum = 100000;
} else if (calc_hum < 0) {
calc_hum = 0;
}
data->calc_humidity = calc_hum;
}
static void bme680_calc_gas_resistance(struct bme680_data *data, uint8_t gas_range,
uint16_t adc_gas_res)
{
int64_t var1, var3;
uint64_t var2;
static const uint32_t look_up1[16] = { 2147483647, 2147483647, 2147483647,
2147483647, 2147483647, 2126008810, 2147483647,
2130303777, 2147483647, 2147483647, 2143188679,
2136746228, 2147483647, 2126008810, 2147483647,
2147483647 };
static const uint32_t look_up2[16] = { 4096000000, 2048000000, 1024000000,
512000000, 255744255, 127110228, 64000000,
32258064, 16016016, 8000000, 4000000, 2000000,
1000000, 500000, 250000, 125000 };
var1 = (int64_t)((1340 + (5 * (int64_t)data->range_sw_err)) *
((int64_t)look_up1[gas_range])) >> 16;
var2 = (((int64_t)((int64_t)adc_gas_res << 15) - (int64_t)(16777216)) + var1);
var3 = (((int64_t)look_up2[gas_range] * (int64_t)var1) >> 9);
data->calc_gas_resistance = (uint32_t)((var3 + ((int64_t)var2 >> 1))
/ (int64_t)var2);
}
static uint8_t bme680_calc_res_heat(struct bme680_data *data, uint16_t heatr_temp)
{
uint8_t heatr_res;
int32_t var1, var2, var3, var4, var5;
int32_t heatr_res_x100;
int32_t amb_temp = 25; /* Assume ambient temperature to be 25 deg C */
if (heatr_temp > 400) { /* Cap temperature */
heatr_temp = 400;
}
var1 = ((amb_temp * data->par_gh3) / 1000) * 256;
var2 = (data->par_gh1 + 784) * (((((data->par_gh2 + 154009)
* heatr_temp * 5) / 100)
+ 3276800) / 10);
var3 = var1 + (var2 / 2);
var4 = (var3 / (data->res_heat_range + 4));
var5 = (131 * data->res_heat_val) + 65536;
heatr_res_x100 = ((var4 / var5) - 250) * 34;
heatr_res = (heatr_res_x100 + 50) / 100;
return heatr_res;
}
static uint8_t bme680_calc_gas_wait(uint16_t dur)
{
uint8_t factor = 0, durval;
if (dur >= 0xfc0) {
durval = 0xff; /* Max duration*/
} else {
while (dur > 0x3F) {
dur = dur / 4;
factor += 1;
}
durval = dur + (factor * 64);
}
return durval;
}
static int bme680_sample_fetch(struct device *dev, enum sensor_channel chan)
{
struct bme680_data *data = dev->driver_data;
uint8_t buff[BME680_LEN_FIELD] = { 0 };
uint8_t gas_range;
uint32_t adc_temp, adc_press;
uint16_t adc_hum, adc_gas_res;
int size = BME680_LEN_FIELD;
int ret;
__ASSERT_NO_MSG(chan == SENSOR_CHAN_ALL);
ret = bme680_reg_read(data, BME680_REG_FIELD0, buff, size);
if (ret < 0) {
return ret;
}
data->new_data = buff[0] & BME680_MSK_NEW_DATA;
data->heatr_stab = buff[14] & BME680_MSK_HEATR_STAB;
adc_press = (uint32_t)(((uint32_t)buff[2] << 12) | ((uint32_t)buff[3] << 4)
| ((uint32_t)buff[4] >> 4));
adc_temp = (uint32_t)(((uint32_t)buff[5] << 12) | ((uint32_t)buff[6] << 4)
| ((uint32_t)buff[7] >> 4));
adc_hum = (uint16_t)(((uint32_t)buff[8] << 8) | (uint32_t)buff[9]);
adc_gas_res = (uint16_t)((uint32_t)buff[13] << 2 | (((uint32_t)buff[14]) >> 6));
gas_range = buff[14] & BME680_MSK_GAS_RANGE;
if (data->new_data) {
bme680_calc_temp(data, adc_temp);
bme680_calc_press(data, adc_press);
bme680_calc_humidity(data, adc_hum);
bme680_calc_gas_resistance(data, gas_range, adc_gas_res);
}
/* Trigger the next measurement */
ret = bme680_reg_write(data, BME680_REG_CTRL_MEAS,
BME680_CTRL_MEAS_VAL);
if (ret < 0) {
return ret;
}
return 0;
}
static int bme680_channel_get(struct device *dev, enum sensor_channel chan,
struct sensor_value *val)
{
struct bme680_data *data = dev->driver_data;
switch (chan) {
case SENSOR_CHAN_AMBIENT_TEMP:
/*
* data->calc_temp has a resolution of 0.01 degC.
* So 5123 equals 51.23 degC.
*/
val->val1 = data->calc_temp / 100;
val->val2 = data->calc_temp % 100 * 10000;
break;
case SENSOR_CHAN_PRESS:
/*
* data->calc_press has a resolution of 1 Pa.
* So 96321 equals 96.321 kPa.
*/
val->val1 = data->calc_press / 1000;
val->val2 = (data->calc_press % 1000) * 1000;
break;
case SENSOR_CHAN_HUMIDITY:
/*
* data->calc_humidity has a resolution of 0.001 %RH.
* So 46333 equals 46.333 %RH.
*/
val->val1 = data->calc_humidity / 1000;
val->val2 = (data->calc_humidity % 1000) * 1000;
break;
case SENSOR_CHAN_GAS_RES:
/*
* data->calc_gas_resistance has a resolution of 1 ohm.
* So 100000 equals 100000 ohms.
*/
val->val1 = data->calc_gas_resistance;
val->val2 = 0;
break;
default:
return -EINVAL;
}
return 0;
}
static int bme680_read_compensation(struct bme680_data *data)
{
uint8_t buff[BME680_LEN_COEFF_ALL];
int err = 0;
err = bme680_reg_read(data, BME680_REG_COEFF1, buff, BME680_LEN_COEFF1);
if (err < 0) {
return err;
}
err = bme680_reg_read(data, BME680_REG_COEFF2, &buff[BME680_LEN_COEFF1],
16);
if (err < 0) {
return err;
}
err = bme680_reg_read(data, BME680_REG_COEFF3,
&buff[BME680_LEN_COEFF1 + BME680_LEN_COEFF2],
BME680_LEN_COEFF3);
if (err < 0) {
return err;
}
/* Temperature related coefficients */
data->par_t1 = (uint16_t)(BME680_CONCAT_BYTES(buff[32], buff[31]));
data->par_t2 = (int16_t)(BME680_CONCAT_BYTES(buff[1], buff[0]));
data->par_t3 = (uint8_t)(buff[2]);
/* Pressure related coefficients */
data->par_p1 = (uint16_t)(BME680_CONCAT_BYTES(buff[5], buff[4]));
data->par_p2 = (int16_t)(BME680_CONCAT_BYTES(buff[7], buff[6]));
data->par_p3 = (int8_t)buff[8];
data->par_p4 = (int16_t)(BME680_CONCAT_BYTES(buff[11], buff[10]));
data->par_p5 = (int16_t)(BME680_CONCAT_BYTES(buff[13], buff[12]));
data->par_p6 = (int8_t)(buff[15]);
data->par_p7 = (int8_t)(buff[14]);
data->par_p8 = (int16_t)(BME680_CONCAT_BYTES(buff[19], buff[18]));
data->par_p9 = (int16_t)(BME680_CONCAT_BYTES(buff[21], buff[20]));
data->par_p10 = (uint8_t)(buff[22]);
/* Humidity related coefficients */
data->par_h1 = (uint16_t)(((uint16_t)buff[25] << 4) | (buff[24] & 0x0f));
data->par_h2 = (uint16_t)(((uint16_t)buff[23] << 4) | ((buff[24]) >> 4));
data->par_h3 = (int8_t)buff[26];
data->par_h4 = (int8_t)buff[27];
data->par_h5 = (int8_t)buff[28];
data->par_h6 = (uint8_t)buff[29];
data->par_h7 = (int8_t)buff[30];
/* Gas heater related coefficients */
data->par_gh1 = (int8_t)buff[35];
data->par_gh2 = (int16_t)(BME680_CONCAT_BYTES(buff[34], buff[33]));
data->par_gh3 = (int8_t)buff[36];
data->res_heat_val = (int8_t)buff[37];
data->res_heat_range = ((buff[39] & BME680_MSK_RH_RANGE) >> 4);
data->range_sw_err = ((int8_t)(buff[41] & BME680_MSK_RANGE_SW_ERR)) / 16;
return 0;
}
static int bme680_chip_init(struct device *dev)
{
struct bme680_data *data = (struct bme680_data *)dev->driver_data;
int err;
err = bme680_reg_read(data, BME680_REG_CHIP_ID, &data->chip_id, 1);
if (err < 0) {
return err;
}
if (data->chip_id == BME680_CHIP_ID) {
LOG_DBG("BME680 chip detected");
} else {
LOG_ERR("Bad BME680 chip id 0x%x", data->chip_id);
return -ENOTSUP;
}
err = bme680_read_compensation(data);
if (err < 0) {
return err;
}
err = bme680_reg_write(data, BME680_REG_CTRL_HUM, BME680_HUMIDITY_OVER);
if (err < 0) {
return err;
}
err = bme680_reg_write(data, BME680_REG_CONFIG, BME680_CONFIG_VAL);
if (err < 0) {
return err;
}
err = bme680_reg_write(data, BME680_REG_CTRL_GAS_1,
BME680_CTRL_GAS_1_VAL);
if (err < 0) {
return err;
}
err = bme680_reg_write(data, BME680_REG_RES_HEAT0,
bme680_calc_res_heat(data, BME680_HEATR_TEMP));
if (err < 0) {
return err;
}
err = bme680_reg_write(data, BME680_REG_GAS_WAIT0,
bme680_calc_gas_wait(BME680_HEATR_DUR_MS));
if (err < 0) {
return err;
}
err = bme680_reg_write(data, BME680_REG_CTRL_MEAS,
BME680_CTRL_MEAS_VAL);
if (err < 0) {
return err;
}
return 0;
}
static int bme680_init(struct device *dev)
{
struct bme680_data *data = dev->driver_data;
data->i2c_master = device_get_binding(
DT_INST_BUS_LABEL(0));
if (!data->i2c_master) {
LOG_ERR("I2C master not found: %s",
DT_INST_BUS_LABEL(0));
return -EINVAL;
}
data->i2c_slave_addr = DT_INST_REG_ADDR(0);
if (bme680_chip_init(dev) < 0) {
return -EINVAL;
}
return 0;
}
static const struct sensor_driver_api bme680_api_funcs = {
.sample_fetch = bme680_sample_fetch,
.channel_get = bme680_channel_get,
};
static struct bme680_data bme680_data;
DEVICE_AND_API_INIT(bme680, DT_INST_LABEL(0), bme680_init, &bme680_data,
NULL, POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY,
&bme680_api_funcs);
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