diff options
Diffstat (limited to 'drivers/iio/chemical/bme680_core.c')
| -rw-r--r-- | drivers/iio/chemical/bme680_core.c | 995 |
1 files changed, 995 insertions, 0 deletions
diff --git a/drivers/iio/chemical/bme680_core.c b/drivers/iio/chemical/bme680_core.c new file mode 100644 index 000000000..b2db59812 --- /dev/null +++ b/drivers/iio/chemical/bme680_core.c @@ -0,0 +1,995 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Bosch BME680 - Temperature, Pressure, Humidity & Gas Sensor + * + * Copyright (C) 2017 - 2018 Bosch Sensortec GmbH + * Copyright (C) 2018 Himanshu Jha <himanshujha199640@gmail.com> + * + * Datasheet: + * https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BME680-DS001-00.pdf + */ +#include <linux/acpi.h> +#include <linux/bitfield.h> +#include <linux/device.h> +#include <linux/module.h> +#include <linux/log2.h> +#include <linux/regmap.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +#include "bme680.h" + +struct bme680_calib { + u16 par_t1; + s16 par_t2; + s8 par_t3; + u16 par_p1; + s16 par_p2; + s8 par_p3; + s16 par_p4; + s16 par_p5; + s8 par_p6; + s8 par_p7; + s16 par_p8; + s16 par_p9; + u8 par_p10; + u16 par_h1; + u16 par_h2; + s8 par_h3; + s8 par_h4; + s8 par_h5; + s8 par_h6; + s8 par_h7; + s8 par_gh1; + s16 par_gh2; + s8 par_gh3; + u8 res_heat_range; + s8 res_heat_val; + s8 range_sw_err; +}; + +struct bme680_data { + struct regmap *regmap; + struct bme680_calib bme680; + u8 oversampling_temp; + u8 oversampling_press; + u8 oversampling_humid; + u16 heater_dur; + u16 heater_temp; + /* + * Carryover value from temperature conversion, used in pressure + * and humidity compensation calculations. + */ + s32 t_fine; +}; + +static const struct regmap_range bme680_volatile_ranges[] = { + regmap_reg_range(BME680_REG_MEAS_STAT_0, BME680_REG_GAS_R_LSB), + regmap_reg_range(BME680_REG_STATUS, BME680_REG_STATUS), + regmap_reg_range(BME680_T2_LSB_REG, BME680_GH3_REG), +}; + +static const struct regmap_access_table bme680_volatile_table = { + .yes_ranges = bme680_volatile_ranges, + .n_yes_ranges = ARRAY_SIZE(bme680_volatile_ranges), +}; + +const struct regmap_config bme680_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .max_register = 0xef, + .volatile_table = &bme680_volatile_table, + .cache_type = REGCACHE_RBTREE, +}; +EXPORT_SYMBOL(bme680_regmap_config); + +static const struct iio_chan_spec bme680_channels[] = { + { + .type = IIO_TEMP, + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) | + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), + }, + { + .type = IIO_PRESSURE, + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) | + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), + }, + { + .type = IIO_HUMIDITYRELATIVE, + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) | + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), + }, + { + .type = IIO_RESISTANCE, + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), + }, +}; + +static const int bme680_oversampling_avail[] = { 1, 2, 4, 8, 16 }; + +static int bme680_read_calib(struct bme680_data *data, + struct bme680_calib *calib) +{ + struct device *dev = regmap_get_device(data->regmap); + unsigned int tmp, tmp_msb, tmp_lsb; + int ret; + __le16 buf; + + /* Temperature related coefficients */ + ret = regmap_bulk_read(data->regmap, BME680_T1_LSB_REG, + (u8 *) &buf, 2); + if (ret < 0) { + dev_err(dev, "failed to read BME680_T1_LSB_REG\n"); + return ret; + } + calib->par_t1 = le16_to_cpu(buf); + + ret = regmap_bulk_read(data->regmap, BME680_T2_LSB_REG, + (u8 *) &buf, 2); + if (ret < 0) { + dev_err(dev, "failed to read BME680_T2_LSB_REG\n"); + return ret; + } + calib->par_t2 = le16_to_cpu(buf); + + ret = regmap_read(data->regmap, BME680_T3_REG, &tmp); + if (ret < 0) { + dev_err(dev, "failed to read BME680_T3_REG\n"); + return ret; + } + calib->par_t3 = tmp; + + /* Pressure related coefficients */ + ret = regmap_bulk_read(data->regmap, BME680_P1_LSB_REG, + (u8 *) &buf, 2); + if (ret < 0) { + dev_err(dev, "failed to read BME680_P1_LSB_REG\n"); + return ret; + } + calib->par_p1 = le16_to_cpu(buf); + + ret = regmap_bulk_read(data->regmap, BME680_P2_LSB_REG, + (u8 *) &buf, 2); + if (ret < 0) { + dev_err(dev, "failed to read BME680_P2_LSB_REG\n"); + return ret; + } + calib->par_p2 = le16_to_cpu(buf); + + ret = regmap_read(data->regmap, BME680_P3_REG, &tmp); + if (ret < 0) { + dev_err(dev, "failed to read BME680_P3_REG\n"); + return ret; + } + calib->par_p3 = tmp; + + ret = regmap_bulk_read(data->regmap, BME680_P4_LSB_REG, + (u8 *) &buf, 2); + if (ret < 0) { + dev_err(dev, "failed to read BME680_P4_LSB_REG\n"); + return ret; + } + calib->par_p4 = le16_to_cpu(buf); + + ret = regmap_bulk_read(data->regmap, BME680_P5_LSB_REG, + (u8 *) &buf, 2); + if (ret < 0) { + dev_err(dev, "failed to read BME680_P5_LSB_REG\n"); + return ret; + } + calib->par_p5 = le16_to_cpu(buf); + + ret = regmap_read(data->regmap, BME680_P6_REG, &tmp); + if (ret < 0) { + dev_err(dev, "failed to read BME680_P6_REG\n"); + return ret; + } + calib->par_p6 = tmp; + + ret = regmap_read(data->regmap, BME680_P7_REG, &tmp); + if (ret < 0) { + dev_err(dev, "failed to read BME680_P7_REG\n"); + return ret; + } + calib->par_p7 = tmp; + + ret = regmap_bulk_read(data->regmap, BME680_P8_LSB_REG, + (u8 *) &buf, 2); + if (ret < 0) { + dev_err(dev, "failed to read BME680_P8_LSB_REG\n"); + return ret; + } + calib->par_p8 = le16_to_cpu(buf); + + ret = regmap_bulk_read(data->regmap, BME680_P9_LSB_REG, + (u8 *) &buf, 2); + if (ret < 0) { + dev_err(dev, "failed to read BME680_P9_LSB_REG\n"); + return ret; + } + calib->par_p9 = le16_to_cpu(buf); + + ret = regmap_read(data->regmap, BME680_P10_REG, &tmp); + if (ret < 0) { + dev_err(dev, "failed to read BME680_P10_REG\n"); + return ret; + } + calib->par_p10 = tmp; + + /* Humidity related coefficients */ + ret = regmap_read(data->regmap, BME680_H1_MSB_REG, &tmp_msb); + if (ret < 0) { + dev_err(dev, "failed to read BME680_H1_MSB_REG\n"); + return ret; + } + + ret = regmap_read(data->regmap, BME680_H1_LSB_REG, &tmp_lsb); + if (ret < 0) { + dev_err(dev, "failed to read BME680_H1_LSB_REG\n"); + return ret; + } + + calib->par_h1 = (tmp_msb << BME680_HUM_REG_SHIFT_VAL) | + (tmp_lsb & BME680_BIT_H1_DATA_MSK); + + ret = regmap_read(data->regmap, BME680_H2_MSB_REG, &tmp_msb); + if (ret < 0) { + dev_err(dev, "failed to read BME680_H2_MSB_REG\n"); + return ret; + } + + ret = regmap_read(data->regmap, BME680_H2_LSB_REG, &tmp_lsb); + if (ret < 0) { + dev_err(dev, "failed to read BME680_H2_LSB_REG\n"); + return ret; + } + + calib->par_h2 = (tmp_msb << BME680_HUM_REG_SHIFT_VAL) | + (tmp_lsb >> BME680_HUM_REG_SHIFT_VAL); + + ret = regmap_read(data->regmap, BME680_H3_REG, &tmp); + if (ret < 0) { + dev_err(dev, "failed to read BME680_H3_REG\n"); + return ret; + } + calib->par_h3 = tmp; + + ret = regmap_read(data->regmap, BME680_H4_REG, &tmp); + if (ret < 0) { + dev_err(dev, "failed to read BME680_H4_REG\n"); + return ret; + } + calib->par_h4 = tmp; + + ret = regmap_read(data->regmap, BME680_H5_REG, &tmp); + if (ret < 0) { + dev_err(dev, "failed to read BME680_H5_REG\n"); + return ret; + } + calib->par_h5 = tmp; + + ret = regmap_read(data->regmap, BME680_H6_REG, &tmp); + if (ret < 0) { + dev_err(dev, "failed to read BME680_H6_REG\n"); + return ret; + } + calib->par_h6 = tmp; + + ret = regmap_read(data->regmap, BME680_H7_REG, &tmp); + if (ret < 0) { + dev_err(dev, "failed to read BME680_H7_REG\n"); + return ret; + } + calib->par_h7 = tmp; + + /* Gas heater related coefficients */ + ret = regmap_read(data->regmap, BME680_GH1_REG, &tmp); + if (ret < 0) { + dev_err(dev, "failed to read BME680_GH1_REG\n"); + return ret; + } + calib->par_gh1 = tmp; + + ret = regmap_bulk_read(data->regmap, BME680_GH2_LSB_REG, + (u8 *) &buf, 2); + if (ret < 0) { + dev_err(dev, "failed to read BME680_GH2_LSB_REG\n"); + return ret; + } + calib->par_gh2 = le16_to_cpu(buf); + + ret = regmap_read(data->regmap, BME680_GH3_REG, &tmp); + if (ret < 0) { + dev_err(dev, "failed to read BME680_GH3_REG\n"); + return ret; + } + calib->par_gh3 = tmp; + + /* Other coefficients */ + ret = regmap_read(data->regmap, BME680_REG_RES_HEAT_RANGE, &tmp); + if (ret < 0) { + dev_err(dev, "failed to read resistance heat range\n"); + return ret; + } + calib->res_heat_range = (tmp & BME680_RHRANGE_MSK) / 16; + + ret = regmap_read(data->regmap, BME680_REG_RES_HEAT_VAL, &tmp); + if (ret < 0) { + dev_err(dev, "failed to read resistance heat value\n"); + return ret; + } + calib->res_heat_val = tmp; + + ret = regmap_read(data->regmap, BME680_REG_RANGE_SW_ERR, &tmp); + if (ret < 0) { + dev_err(dev, "failed to read range software error\n"); + return ret; + } + calib->range_sw_err = (tmp & BME680_RSERROR_MSK) / 16; + + return 0; +} + +/* + * Taken from Bosch BME680 API: + * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L876 + * + * Returns temperature measurement in DegC, resolutions is 0.01 DegC. Therefore, + * output value of "3233" represents 32.33 DegC. + */ +static s16 bme680_compensate_temp(struct bme680_data *data, + s32 adc_temp) +{ + struct bme680_calib *calib = &data->bme680; + s64 var1, var2, var3; + s16 calc_temp; + + /* If the calibration is invalid, attempt to reload it */ + if (!calib->par_t2) + bme680_read_calib(data, calib); + + var1 = (adc_temp >> 3) - (calib->par_t1 << 1); + var2 = (var1 * calib->par_t2) >> 11; + var3 = ((var1 >> 1) * (var1 >> 1)) >> 12; + var3 = (var3 * (calib->par_t3 << 4)) >> 14; + data->t_fine = var2 + var3; + calc_temp = (data->t_fine * 5 + 128) >> 8; + + return calc_temp; +} + +/* + * Taken from Bosch BME680 API: + * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L896 + * + * Returns pressure measurement in Pa. Output value of "97356" represents + * 97356 Pa = 973.56 hPa. + */ +static u32 bme680_compensate_press(struct bme680_data *data, + u32 adc_press) +{ + struct bme680_calib *calib = &data->bme680; + s32 var1, var2, var3, press_comp; + + var1 = (data->t_fine >> 1) - 64000; + var2 = ((((var1 >> 2) * (var1 >> 2)) >> 11) * calib->par_p6) >> 2; + var2 = var2 + (var1 * calib->par_p5 << 1); + var2 = (var2 >> 2) + (calib->par_p4 << 16); + var1 = (((((var1 >> 2) * (var1 >> 2)) >> 13) * + (calib->par_p3 << 5)) >> 3) + + ((calib->par_p2 * var1) >> 1); + var1 = var1 >> 18; + var1 = ((32768 + var1) * calib->par_p1) >> 15; + press_comp = 1048576 - adc_press; + press_comp = ((press_comp - (var2 >> 12)) * 3125); + + if (press_comp >= BME680_MAX_OVERFLOW_VAL) + press_comp = ((press_comp / (u32)var1) << 1); + else + press_comp = ((press_comp << 1) / (u32)var1); + + var1 = (calib->par_p9 * (((press_comp >> 3) * + (press_comp >> 3)) >> 13)) >> 12; + var2 = ((press_comp >> 2) * calib->par_p8) >> 13; + var3 = ((press_comp >> 8) * (press_comp >> 8) * + (press_comp >> 8) * calib->par_p10) >> 17; + + press_comp += (var1 + var2 + var3 + (calib->par_p7 << 7)) >> 4; + + return press_comp; +} + +/* + * Taken from Bosch BME680 API: + * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L937 + * + * Returns humidity measurement in percent, resolution is 0.001 percent. Output + * value of "43215" represents 43.215 %rH. + */ +static u32 bme680_compensate_humid(struct bme680_data *data, + u16 adc_humid) +{ + struct bme680_calib *calib = &data->bme680; + s32 var1, var2, var3, var4, var5, var6, temp_scaled, calc_hum; + + temp_scaled = (data->t_fine * 5 + 128) >> 8; + var1 = (adc_humid - ((s32) ((s32) calib->par_h1 * 16))) - + (((temp_scaled * (s32) calib->par_h3) / 100) >> 1); + var2 = ((s32) calib->par_h2 * + (((temp_scaled * calib->par_h4) / 100) + + (((temp_scaled * ((temp_scaled * calib->par_h5) / 100)) + >> 6) / 100) + (1 << 14))) >> 10; + var3 = var1 * var2; + var4 = calib->par_h6 << 7; + var4 = (var4 + ((temp_scaled * calib->par_h7) / 100)) >> 4; + var5 = ((var3 >> 14) * (var3 >> 14)) >> 10; + var6 = (var4 * var5) >> 1; + calc_hum = (((var3 + var6) >> 10) * 1000) >> 12; + + if (calc_hum > 100000) /* Cap at 100%rH */ + calc_hum = 100000; + else if (calc_hum < 0) + calc_hum = 0; + + return calc_hum; +} + +/* + * Taken from Bosch BME680 API: + * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L973 + * + * Returns gas measurement in Ohm. Output value of "82986" represent 82986 ohms. + */ +static u32 bme680_compensate_gas(struct bme680_data *data, u16 gas_res_adc, + u8 gas_range) +{ + struct bme680_calib *calib = &data->bme680; + s64 var1; + u64 var2; + s64 var3; + u32 calc_gas_res; + + /* Look up table for the possible gas range values */ + const u32 lookupTable[16] = {2147483647u, 2147483647u, + 2147483647u, 2147483647u, 2147483647u, + 2126008810u, 2147483647u, 2130303777u, + 2147483647u, 2147483647u, 2143188679u, + 2136746228u, 2147483647u, 2126008810u, + 2147483647u, 2147483647u}; + + var1 = ((1340 + (5 * (s64) calib->range_sw_err)) * + ((s64) lookupTable[gas_range])) >> 16; + var2 = ((gas_res_adc << 15) - 16777216) + var1; + var3 = ((125000 << (15 - gas_range)) * var1) >> 9; + var3 += (var2 >> 1); + calc_gas_res = div64_s64(var3, (s64) var2); + + return calc_gas_res; +} + +/* + * Taken from Bosch BME680 API: + * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L1002 + */ +static u8 bme680_calc_heater_res(struct bme680_data *data, u16 temp) +{ + struct bme680_calib *calib = &data->bme680; + s32 var1, var2, var3, var4, var5, heatr_res_x100; + u8 heatr_res; + + if (temp > 400) /* Cap temperature */ + temp = 400; + + var1 = (((s32) BME680_AMB_TEMP * calib->par_gh3) / 1000) * 256; + var2 = (calib->par_gh1 + 784) * (((((calib->par_gh2 + 154009) * + temp * 5) / 100) + + 3276800) / 10); + var3 = var1 + (var2 / 2); + var4 = (var3 / (calib->res_heat_range + 4)); + var5 = 131 * calib->res_heat_val + 65536; + heatr_res_x100 = ((var4 / var5) - 250) * 34; + heatr_res = (heatr_res_x100 + 50) / 100; + + return heatr_res; +} + +/* + * Taken from Bosch BME680 API: + * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#L1188 + */ +static u8 bme680_calc_heater_dur(u16 dur) +{ + u8 durval, factor = 0; + + 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_set_mode(struct bme680_data *data, bool mode) +{ + struct device *dev = regmap_get_device(data->regmap); + int ret; + + if (mode) { + ret = regmap_write_bits(data->regmap, BME680_REG_CTRL_MEAS, + BME680_MODE_MASK, BME680_MODE_FORCED); + if (ret < 0) + dev_err(dev, "failed to set forced mode\n"); + + } else { + ret = regmap_write_bits(data->regmap, BME680_REG_CTRL_MEAS, + BME680_MODE_MASK, BME680_MODE_SLEEP); + if (ret < 0) + dev_err(dev, "failed to set sleep mode\n"); + + } + + return ret; +} + +static int bme680_chip_config(struct bme680_data *data) +{ + struct device *dev = regmap_get_device(data->regmap); + int ret; + u8 osrs = FIELD_PREP(BME680_OSRS_HUMIDITY_MASK, + data->oversampling_humid + 1); + /* + * Highly recommended to set oversampling of humidity before + * temperature/pressure oversampling. + */ + ret = regmap_update_bits(data->regmap, BME680_REG_CTRL_HUMIDITY, + BME680_OSRS_HUMIDITY_MASK, osrs); + if (ret < 0) { + dev_err(dev, "failed to write ctrl_hum register\n"); + return ret; + } + + /* IIR filter settings */ + ret = regmap_update_bits(data->regmap, BME680_REG_CONFIG, + BME680_FILTER_MASK, + BME680_FILTER_COEFF_VAL); + if (ret < 0) { + dev_err(dev, "failed to write config register\n"); + return ret; + } + + osrs = FIELD_PREP(BME680_OSRS_TEMP_MASK, data->oversampling_temp + 1) | + FIELD_PREP(BME680_OSRS_PRESS_MASK, data->oversampling_press + 1); + + ret = regmap_write_bits(data->regmap, BME680_REG_CTRL_MEAS, + BME680_OSRS_TEMP_MASK | + BME680_OSRS_PRESS_MASK, + osrs); + if (ret < 0) + dev_err(dev, "failed to write ctrl_meas register\n"); + + return ret; +} + +static int bme680_gas_config(struct bme680_data *data) +{ + struct device *dev = regmap_get_device(data->regmap); + int ret; + u8 heatr_res, heatr_dur; + + heatr_res = bme680_calc_heater_res(data, data->heater_temp); + + /* set target heater temperature */ + ret = regmap_write(data->regmap, BME680_REG_RES_HEAT_0, heatr_res); + if (ret < 0) { + dev_err(dev, "failed to write res_heat_0 register\n"); + return ret; + } + + heatr_dur = bme680_calc_heater_dur(data->heater_dur); + + /* set target heating duration */ + ret = regmap_write(data->regmap, BME680_REG_GAS_WAIT_0, heatr_dur); + if (ret < 0) { + dev_err(dev, "failted to write gas_wait_0 register\n"); + return ret; + } + + /* Selecting the runGas and NB conversion settings for the sensor */ + ret = regmap_update_bits(data->regmap, BME680_REG_CTRL_GAS_1, + BME680_RUN_GAS_MASK | BME680_NB_CONV_MASK, + BME680_RUN_GAS_EN_BIT | BME680_NB_CONV_0_VAL); + if (ret < 0) + dev_err(dev, "failed to write ctrl_gas_1 register\n"); + + return ret; +} + +static int bme680_read_temp(struct bme680_data *data, int *val) +{ + struct device *dev = regmap_get_device(data->regmap); + int ret; + __be32 tmp = 0; + s32 adc_temp; + s16 comp_temp; + + /* set forced mode to trigger measurement */ + ret = bme680_set_mode(data, true); + if (ret < 0) + return ret; + + ret = regmap_bulk_read(data->regmap, BME680_REG_TEMP_MSB, + (u8 *) &tmp, 3); + if (ret < 0) { + dev_err(dev, "failed to read temperature\n"); + return ret; + } + + adc_temp = be32_to_cpu(tmp) >> 12; + if (adc_temp == BME680_MEAS_SKIPPED) { + /* reading was skipped */ + dev_err(dev, "reading temperature skipped\n"); + return -EINVAL; + } + comp_temp = bme680_compensate_temp(data, adc_temp); + /* + * val might be NULL if we're called by the read_press/read_humid + * routine which is callled to get t_fine value used in + * compensate_press/compensate_humid to get compensated + * pressure/humidity readings. + */ + if (val) { + *val = comp_temp * 10; /* Centidegrees to millidegrees */ + return IIO_VAL_INT; + } + + return ret; +} + +static int bme680_read_press(struct bme680_data *data, + int *val, int *val2) +{ + struct device *dev = regmap_get_device(data->regmap); + int ret; + __be32 tmp = 0; + s32 adc_press; + + /* Read and compensate temperature to get a reading of t_fine */ + ret = bme680_read_temp(data, NULL); + if (ret < 0) + return ret; + + ret = regmap_bulk_read(data->regmap, BME680_REG_PRESS_MSB, + (u8 *) &tmp, 3); + if (ret < 0) { + dev_err(dev, "failed to read pressure\n"); + return ret; + } + + adc_press = be32_to_cpu(tmp) >> 12; + if (adc_press == BME680_MEAS_SKIPPED) { + /* reading was skipped */ + dev_err(dev, "reading pressure skipped\n"); + return -EINVAL; + } + + *val = bme680_compensate_press(data, adc_press); + *val2 = 100; + return IIO_VAL_FRACTIONAL; +} + +static int bme680_read_humid(struct bme680_data *data, + int *val, int *val2) +{ + struct device *dev = regmap_get_device(data->regmap); + int ret; + __be16 tmp = 0; + s32 adc_humidity; + u32 comp_humidity; + + /* Read and compensate temperature to get a reading of t_fine */ + ret = bme680_read_temp(data, NULL); + if (ret < 0) + return ret; + + ret = regmap_bulk_read(data->regmap, BM6880_REG_HUMIDITY_MSB, + (u8 *) &tmp, 2); + if (ret < 0) { + dev_err(dev, "failed to read humidity\n"); + return ret; + } + + adc_humidity = be16_to_cpu(tmp); + if (adc_humidity == BME680_MEAS_SKIPPED) { + /* reading was skipped */ + dev_err(dev, "reading humidity skipped\n"); + return -EINVAL; + } + comp_humidity = bme680_compensate_humid(data, adc_humidity); + + *val = comp_humidity; + *val2 = 1000; + return IIO_VAL_FRACTIONAL; +} + +static int bme680_read_gas(struct bme680_data *data, + int *val) +{ + struct device *dev = regmap_get_device(data->regmap); + int ret; + __be16 tmp = 0; + unsigned int check; + u16 adc_gas_res; + u8 gas_range; + + /* Set heater settings */ + ret = bme680_gas_config(data); + if (ret < 0) { + dev_err(dev, "failed to set gas config\n"); + return ret; + } + + /* set forced mode to trigger measurement */ + ret = bme680_set_mode(data, true); + if (ret < 0) + return ret; + + ret = regmap_read(data->regmap, BME680_REG_MEAS_STAT_0, &check); + if (check & BME680_GAS_MEAS_BIT) { + dev_err(dev, "gas measurement incomplete\n"); + return -EBUSY; + } + + ret = regmap_read(data->regmap, BME680_REG_GAS_R_LSB, &check); + if (ret < 0) { + dev_err(dev, "failed to read gas_r_lsb register\n"); + return ret; + } + + /* + * occurs if either the gas heating duration was insuffient + * to reach the target heater temperature or the target + * heater temperature was too high for the heater sink to + * reach. + */ + if ((check & BME680_GAS_STAB_BIT) == 0) { + dev_err(dev, "heater failed to reach the target temperature\n"); + return -EINVAL; + } + + ret = regmap_bulk_read(data->regmap, BME680_REG_GAS_MSB, + (u8 *) &tmp, 2); + if (ret < 0) { + dev_err(dev, "failed to read gas resistance\n"); + return ret; + } + + gas_range = check & BME680_GAS_RANGE_MASK; + adc_gas_res = be16_to_cpu(tmp) >> BME680_ADC_GAS_RES_SHIFT; + + *val = bme680_compensate_gas(data, adc_gas_res, gas_range); + return IIO_VAL_INT; +} + +static int bme680_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct bme680_data *data = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_PROCESSED: + switch (chan->type) { + case IIO_TEMP: + return bme680_read_temp(data, val); + case IIO_PRESSURE: + return bme680_read_press(data, val, val2); + case IIO_HUMIDITYRELATIVE: + return bme680_read_humid(data, val, val2); + case IIO_RESISTANCE: + return bme680_read_gas(data, val); + default: + return -EINVAL; + } + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: + switch (chan->type) { + case IIO_TEMP: + *val = 1 << data->oversampling_temp; + return IIO_VAL_INT; + case IIO_PRESSURE: + *val = 1 << data->oversampling_press; + return IIO_VAL_INT; + case IIO_HUMIDITYRELATIVE: + *val = 1 << data->oversampling_humid; + return IIO_VAL_INT; + default: + return -EINVAL; + } + default: + return -EINVAL; + } +} + +static int bme680_write_oversampling_ratio_temp(struct bme680_data *data, + int val) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(bme680_oversampling_avail); i++) { + if (bme680_oversampling_avail[i] == val) { + data->oversampling_temp = ilog2(val); + + return bme680_chip_config(data); + } + } + + return -EINVAL; +} + +static int bme680_write_oversampling_ratio_press(struct bme680_data *data, + int val) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(bme680_oversampling_avail); i++) { + if (bme680_oversampling_avail[i] == val) { + data->oversampling_press = ilog2(val); + + return bme680_chip_config(data); + } + } + + return -EINVAL; +} + +static int bme680_write_oversampling_ratio_humid(struct bme680_data *data, + int val) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(bme680_oversampling_avail); i++) { + if (bme680_oversampling_avail[i] == val) { + data->oversampling_humid = ilog2(val); + + return bme680_chip_config(data); + } + } + + return -EINVAL; +} + +static int bme680_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + struct bme680_data *data = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: + switch (chan->type) { + case IIO_TEMP: + return bme680_write_oversampling_ratio_temp(data, val); + case IIO_PRESSURE: + return bme680_write_oversampling_ratio_press(data, val); + case IIO_HUMIDITYRELATIVE: + return bme680_write_oversampling_ratio_humid(data, val); + default: + return -EINVAL; + } + default: + return -EINVAL; + } +} + +static const char bme680_oversampling_ratio_show[] = "1 2 4 8 16"; + +static IIO_CONST_ATTR(oversampling_ratio_available, + bme680_oversampling_ratio_show); + +static struct attribute *bme680_attributes[] = { + &iio_const_attr_oversampling_ratio_available.dev_attr.attr, + NULL, +}; + +static const struct attribute_group bme680_attribute_group = { + .attrs = bme680_attributes, +}; + +static const struct iio_info bme680_info = { + .read_raw = &bme680_read_raw, + .write_raw = &bme680_write_raw, + .attrs = &bme680_attribute_group, +}; + +static const char *bme680_match_acpi_device(struct device *dev) +{ + const struct acpi_device_id *id; + + id = acpi_match_device(dev->driver->acpi_match_table, dev); + if (!id) + return NULL; + + return dev_name(dev); +} + +int bme680_core_probe(struct device *dev, struct regmap *regmap, + const char *name) +{ + struct iio_dev *indio_dev; + struct bme680_data *data; + unsigned int val; + int ret; + + ret = regmap_write(regmap, BME680_REG_SOFT_RESET, + BME680_CMD_SOFTRESET); + if (ret < 0) { + dev_err(dev, "Failed to reset chip\n"); + return ret; + } + + ret = regmap_read(regmap, BME680_REG_CHIP_ID, &val); + if (ret < 0) { + dev_err(dev, "Error reading chip ID\n"); + return ret; + } + + if (val != BME680_CHIP_ID_VAL) { + dev_err(dev, "Wrong chip ID, got %x expected %x\n", + val, BME680_CHIP_ID_VAL); + return -ENODEV; + } + + indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + + if (!name && ACPI_HANDLE(dev)) + name = bme680_match_acpi_device(dev); + + data = iio_priv(indio_dev); + dev_set_drvdata(dev, indio_dev); + data->regmap = regmap; + indio_dev->dev.parent = dev; + indio_dev->name = name; + indio_dev->channels = bme680_channels; + indio_dev->num_channels = ARRAY_SIZE(bme680_channels); + indio_dev->info = &bme680_info; + indio_dev->modes = INDIO_DIRECT_MODE; + + /* default values for the sensor */ + data->oversampling_humid = ilog2(2); /* 2X oversampling rate */ + data->oversampling_press = ilog2(4); /* 4X oversampling rate */ + data->oversampling_temp = ilog2(8); /* 8X oversampling rate */ + data->heater_temp = 320; /* degree Celsius */ + data->heater_dur = 150; /* milliseconds */ + + ret = bme680_chip_config(data); + if (ret < 0) { + dev_err(dev, "failed to set chip_config data\n"); + return ret; + } + + ret = bme680_gas_config(data); + if (ret < 0) { + dev_err(dev, "failed to set gas config data\n"); + return ret; + } + + ret = bme680_read_calib(data, &data->bme680); + if (ret < 0) { + dev_err(dev, + "failed to read calibration coefficients at probe\n"); + return ret; + } + + return devm_iio_device_register(dev, indio_dev); +} +EXPORT_SYMBOL_GPL(bme680_core_probe); + +MODULE_AUTHOR("Himanshu Jha <himanshujha199640@gmail.com>"); +MODULE_DESCRIPTION("Bosch BME680 Driver"); +MODULE_LICENSE("GPL v2"); |