Commit 56686ac8 authored by Vasileios Amoiridis's avatar Vasileios Amoiridis Committed by Jonathan Cameron
Browse files

iio: chemical: bme680: Add support for preheat current 



Add functionality to inject a specified amount of current to the heating
plate before the start of the gas measurement to allow the sensor to reach
faster to the requested temperature.

Signed-off-by: default avatarVasileios Amoiridis <vassilisamir@gmail.com>
Link: https://patch.msgid.link/20241102131311.36210-5-vassilisamir@gmail.com


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 80b9f3a8

drivers/iio/chemical/bme680.h

+1 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ 
#define   BME680_RHRANGE_MASK			GENMASK(5, 4)

#define BME680_REG_RES_HEAT_VAL			0x00

#define   BME680_RSERROR_MASK			GENMASK(7, 4)

#define BME680_REG_IDAC_HEAT_0			0x50

#define BME680_REG_RES_HEAT_0			0x5A

#define BME680_REG_GAS_WAIT_0			0x64

#define BME680_ADC_GAS_RES			GENMASK(15, 6)

drivers/iio/chemical/bme680_core.c

+41 −0
Original line number Diff line number Diff line
@@ -118,6 +118,7 @@ struct bme680_data { 
	u8 oversampling_temp;

	u8 oversampling_press;

	u8 oversampling_humid;

	u8 preheat_curr_mA;

	u16 heater_dur;

	u16 heater_temp;
@@ -214,6 +215,12 @@ static const struct iio_chan_spec bme680_channels[] = { 
		},

	},

	IIO_CHAN_SOFT_TIMESTAMP(4),

	{

		.type = IIO_CURRENT,

		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),

		.output = 1,

		.scan_index = -1,

	},

};



static int bme680_read_calib(struct bme680_data *data,
@@ -561,6 +568,12 @@ static u8 bme680_calc_heater_dur(u16 dur) 
	return durval;

}



/* Taken from datasheet, section 5.3.3 */

static u8 bme680_calc_heater_preheat_current(u8 curr)

{

	return 8 * curr - 1;

}



static int bme680_set_mode(struct bme680_data *data, enum bme680_op_mode mode)

{

	struct device *dev = regmap_get_device(data->regmap);
@@ -659,6 +672,20 @@ static int bme680_chip_config(struct bme680_data *data) 
	return 0;

}



static int bme680_preheat_curr_config(struct bme680_data *data, u8 val)

{

	struct device *dev = regmap_get_device(data->regmap);

	u8 heatr_curr;

	int ret;



	heatr_curr = bme680_calc_heater_preheat_current(val);

	ret = regmap_write(data->regmap, BME680_REG_IDAC_HEAT_0, heatr_curr);

	if (ret < 0)

		dev_err(dev, "failed to write idac_heat_0 register\n");



	return ret;

}



static int bme680_gas_config(struct bme680_data *data)

{

	struct device *dev = regmap_get_device(data->regmap);
@@ -687,6 +714,10 @@ static int bme680_gas_config(struct bme680_data *data) 
		return ret;

	}



	ret = bme680_preheat_curr_config(data, data->preheat_curr_mA);

	if (ret)

		return ret;



	/* Enable the gas sensor and select heater profile set-point 0 */

	ret = regmap_update_bits(data->regmap, BME680_REG_CTRL_GAS_1,

				 BME680_RUN_GAS_MASK | BME680_NB_CONV_MASK,
@@ -939,6 +970,15 @@ static int bme680_write_raw(struct iio_dev *indio_dev, 


		return bme680_chip_config(data);

	}

	case IIO_CHAN_INFO_PROCESSED:

	{

		switch (chan->type) {

		case IIO_CURRENT:

			return bme680_preheat_curr_config(data, (u8)val);

		default:

			return -EINVAL;

		}

	}

	default:

		return -EINVAL;

	}
@@ -1072,6 +1112,7 @@ int bme680_core_probe(struct device *dev, struct regmap *regmap, 
	data->oversampling_temp = 8;  /* 8X oversampling rate */

	data->heater_temp = 320; /* degree Celsius */

	data->heater_dur = 150;  /* milliseconds */

	data->preheat_curr_mA = 0;



	ret = regmap_write(regmap, BME680_REG_SOFT_RESET, BME680_CMD_SOFTRESET);

	if (ret < 0)