v4.19.13 snapshot.
diff --git a/drivers/iio/chemical/bme680.h b/drivers/iio/chemical/bme680.h
new file mode 100644
index 0000000..e049323
--- /dev/null
+++ b/drivers/iio/chemical/bme680.h
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef BME680_H_
+#define BME680_H_
+
+#define BME680_REG_CHIP_I2C_ID 0xD0
+#define BME680_REG_CHIP_SPI_ID 0x50
+#define BME680_CHIP_ID_VAL 0x61
+#define BME680_REG_SOFT_RESET_I2C 0xE0
+#define BME680_REG_SOFT_RESET_SPI 0x60
+#define BME680_CMD_SOFTRESET 0xB6
+#define BME680_REG_STATUS 0x73
+#define BME680_SPI_MEM_PAGE_BIT BIT(4)
+#define BME680_SPI_MEM_PAGE_1_VAL 1
+
+#define BME680_REG_TEMP_MSB 0x22
+#define BME680_REG_PRESS_MSB 0x1F
+#define BM6880_REG_HUMIDITY_MSB 0x25
+#define BME680_REG_GAS_MSB 0x2A
+#define BME680_REG_GAS_R_LSB 0x2B
+#define BME680_GAS_STAB_BIT BIT(4)
+
+#define BME680_REG_CTRL_HUMIDITY 0x72
+#define BME680_OSRS_HUMIDITY_MASK GENMASK(2, 0)
+
+#define BME680_REG_CTRL_MEAS 0x74
+#define BME680_OSRS_TEMP_MASK GENMASK(7, 5)
+#define BME680_OSRS_PRESS_MASK GENMASK(4, 2)
+#define BME680_MODE_MASK GENMASK(1, 0)
+
+#define BME680_MODE_FORCED 1
+#define BME680_MODE_SLEEP 0
+
+#define BME680_REG_CONFIG 0x75
+#define BME680_FILTER_MASK GENMASK(4, 2)
+#define BME680_FILTER_COEFF_VAL BIT(1)
+
+/* TEMP/PRESS/HUMID reading skipped */
+#define BME680_MEAS_SKIPPED 0x8000
+
+#define BME680_MAX_OVERFLOW_VAL 0x40000000
+#define BME680_HUM_REG_SHIFT_VAL 4
+#define BME680_BIT_H1_DATA_MSK 0x0F
+
+#define BME680_REG_RES_HEAT_RANGE 0x02
+#define BME680_RHRANGE_MSK 0x30
+#define BME680_REG_RES_HEAT_VAL 0x00
+#define BME680_REG_RANGE_SW_ERR 0x04
+#define BME680_RSERROR_MSK 0xF0
+#define BME680_REG_RES_HEAT_0 0x5A
+#define BME680_REG_GAS_WAIT_0 0x64
+#define BME680_GAS_RANGE_MASK 0x0F
+#define BME680_ADC_GAS_RES_SHIFT 6
+#define BME680_AMB_TEMP 25
+
+#define BME680_REG_CTRL_GAS_1 0x71
+#define BME680_RUN_GAS_MASK BIT(4)
+#define BME680_NB_CONV_MASK GENMASK(3, 0)
+#define BME680_RUN_GAS_EN_BIT BIT(4)
+#define BME680_NB_CONV_0_VAL 0
+
+#define BME680_REG_MEAS_STAT_0 0x1D
+#define BME680_GAS_MEAS_BIT BIT(6)
+
+/* Calibration Parameters */
+#define BME680_T2_LSB_REG 0x8A
+#define BME680_T3_REG 0x8C
+#define BME680_P1_LSB_REG 0x8E
+#define BME680_P2_LSB_REG 0x90
+#define BME680_P3_REG 0x92
+#define BME680_P4_LSB_REG 0x94
+#define BME680_P5_LSB_REG 0x96
+#define BME680_P7_REG 0x98
+#define BME680_P6_REG 0x99
+#define BME680_P8_LSB_REG 0x9C
+#define BME680_P9_LSB_REG 0x9E
+#define BME680_P10_REG 0xA0
+#define BME680_H2_LSB_REG 0xE2
+#define BME680_H2_MSB_REG 0xE1
+#define BME680_H1_MSB_REG 0xE3
+#define BME680_H1_LSB_REG 0xE2
+#define BME680_H3_REG 0xE4
+#define BME680_H4_REG 0xE5
+#define BME680_H5_REG 0xE6
+#define BME680_H6_REG 0xE7
+#define BME680_H7_REG 0xE8
+#define BME680_T1_LSB_REG 0xE9
+#define BME680_GH2_LSB_REG 0xEB
+#define BME680_GH1_REG 0xED
+#define BME680_GH3_REG 0xEE
+
+extern const struct regmap_config bme680_regmap_config;
+
+int bme680_core_probe(struct device *dev, struct regmap *regmap,
+ const char *name);
+
+#endif /* BME680_H_ */