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So the bme680_read_{press/humid}() functions of the above sensors are internally calling the equivalent bme680_read_temp() function in order to update the t_fine value. By just looking at the code this relation is a bit hidden and is not easy to understand why those channels are not independent. This commit tries to clear these thing a bit by splitting the bme680_{read/compensate}_{temp/press/humid}() to the following: i. bme680_read_{temp/press/humid}_adc(): read the raw value from the sensor. ii. bme680_calc_t_fine(): calculate the t_fine variable. iii. bme680_get_t_fine(): get the t_fine variable. iv. bme680_compensate_{temp/press/humid}(): compensate the adc values and return the calculated value. v. bme680_read_{temp/press/humid}(): combine calls of the aforementioned functions to return the requested value. Signed-off-by: Vasileios Amoiridis --- drivers/iio/chemical/bme680_core.c | 192 +++++++++++++++++------------ 1 file changed, 116 insertions(+), 76 deletions(-) diff --git a/drivers/iio/chemical/bme680_core.c b/drivers/iio/chemical/bme6= 80_core.c index b654a8cd31aa..6d0069d2dfb2 100644 --- a/drivers/iio/chemical/bme680_core.c +++ b/drivers/iio/chemical/bme680_core.c @@ -104,11 +104,6 @@ struct bme680_data { u8 oversampling_humid; u16 heater_dur; u16 heater_temp; - /* - * Carryover value from temperature conversion, used in pressure - * and humidity compensation calculations. - */ - s32 t_fine; =20 union { u8 buf[3]; @@ -237,6 +232,31 @@ static int bme680_read_calib(struct bme680_data *data, return 0; } =20 +static int bme680_read_temp_adc(struct bme680_data *data, u32 *adc_temp) +{ + struct device *dev =3D regmap_get_device(data->regmap); + u32 value_temp; + int ret; + + ret =3D regmap_bulk_read(data->regmap, BME680_REG_TEMP_MSB, + data->buf, BME680_TEMP_NUM_BYTES); + if (ret < 0) { + dev_err(dev, "failed to read temperature\n"); + return ret; + } + + value_temp =3D FIELD_GET(BME680_MEAS_TRIM_MASK, + get_unaligned_be24(data->buf)); + if (value_temp =3D=3D BME680_MEAS_SKIPPED) { + /* reading was skipped */ + dev_err(dev, "reading temperature skipped\n"); + return -EINVAL; + } + *adc_temp =3D value_temp; + + return 0; +} + /* * Taken from Bosch BME680 API: * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#= L876 @@ -244,12 +264,10 @@ static int bme680_read_calib(struct bme680_data *data, * Returns temperature measurement in DegC, resolutions is 0.01 DegC. Ther= efore, * output value of "3233" represents 32.33 DegC. */ -static s16 bme680_compensate_temp(struct bme680_data *data, - u32 adc_temp) +static s32 bme680_calc_t_fine(struct bme680_data *data, u32 adc_temp) { struct bme680_calib *calib =3D &data->bme680; s64 var1, var2, var3; - s16 calc_temp; =20 /* If the calibration is invalid, attempt to reload it */ if (!calib->par_t2) @@ -259,10 +277,52 @@ static s16 bme680_compensate_temp(struct bme680_data = *data, var2 =3D (var1 * calib->par_t2) >> 11; var3 =3D ((var1 >> 1) * (var1 >> 1)) >> 12; var3 =3D (var3 * ((s32)calib->par_t3 << 4)) >> 14; - data->t_fine =3D var2 + var3; - calc_temp =3D (data->t_fine * 5 + 128) >> 8; + return var2 + var3; /* t_fine =3D var2 + var3 */ +} + +static int bme680_get_t_fine(struct bme680_data *data, s32 *t_fine) +{ + u32 adc_temp; + int ret; + + ret =3D bme680_read_temp_adc(data, &adc_temp); + if (ret) + return ret; + + *t_fine =3D bme680_calc_t_fine(data, adc_temp); + + return 0; +} =20 - return calc_temp; +static s16 bme680_compensate_temp(struct bme680_data *data, + u32 adc_temp) +{ + return (bme680_calc_t_fine(data, adc_temp) * 5 + 128) / 256; +} + +static int bme680_read_press_adc(struct bme680_data *data, u32 *adc_press) +{ + struct device *dev =3D regmap_get_device(data->regmap); + u32 value_press; + int ret; + + ret =3D regmap_bulk_read(data->regmap, BME680_REG_PRESS_MSB, + data->buf, BME680_PRESS_NUM_BYTES); + if (ret < 0) { + dev_err(dev, "failed to read pressure\n"); + return ret; + } + + value_press =3D FIELD_GET(BME680_MEAS_TRIM_MASK, + get_unaligned_be24(data->buf)); + if (value_press =3D=3D BME680_MEAS_SKIPPED) { + /* reading was skipped */ + dev_err(dev, "reading pressure skipped\n"); + return -EINVAL; + } + *adc_press =3D value_press; + + return 0; } =20 /* @@ -273,12 +333,12 @@ static s16 bme680_compensate_temp(struct bme680_data = *data, * 97356 Pa =3D 973.56 hPa. */ static u32 bme680_compensate_press(struct bme680_data *data, - u32 adc_press) + u32 adc_press, s32 t_fine) { struct bme680_calib *calib =3D &data->bme680; s32 var1, var2, var3, press_comp; =20 - var1 =3D (data->t_fine >> 1) - 64000; + var1 =3D (t_fine >> 1) - 64000; var2 =3D ((((var1 >> 2) * (var1 >> 2)) >> 11) * calib->par_p6) >> 2; var2 =3D var2 + (var1 * calib->par_p5 << 1); var2 =3D (var2 >> 2) + ((s32)calib->par_p4 << 16); @@ -306,6 +366,30 @@ static u32 bme680_compensate_press(struct bme680_data = *data, return press_comp; } =20 +static int bme680_read_humid_adc(struct bme680_data *data, u32 *adc_humidi= ty) +{ + struct device *dev =3D regmap_get_device(data->regmap); + u32 value_humidity; + int ret; + + ret =3D regmap_bulk_read(data->regmap, BME680_REG_HUMIDITY_MSB, + &data->be16, BME680_HUMID_NUM_BYTES); + if (ret < 0) { + dev_err(dev, "failed to read humidity\n"); + return ret; + } + + value_humidity =3D be16_to_cpu(data->be16); + if (value_humidity =3D=3D BME680_MEAS_SKIPPED) { + /* reading was skipped */ + dev_err(dev, "reading humidity skipped\n"); + return -EINVAL; + } + *adc_humidity =3D value_humidity; + + return 0; +} + /* * Taken from Bosch BME680 API: * https://github.com/BoschSensortec/BME680_driver/blob/63bb5336/bme680.c#= L937 @@ -314,12 +398,12 @@ static u32 bme680_compensate_press(struct bme680_data= *data, * value of "43215" represents 43.215 %rH. */ static u32 bme680_compensate_humid(struct bme680_data *data, - u16 adc_humid) + u16 adc_humid, s32 t_fine) { struct bme680_calib *calib =3D &data->bme680; s32 var1, var2, var3, var4, var5, var6, temp_scaled, calc_hum; =20 - temp_scaled =3D (data->t_fine * 5 + 128) >> 8; + temp_scaled =3D (t_fine * 5 + 128) >> 8; var1 =3D (adc_humid - (((s32)calib->par_h1 * 16))) - (((temp_scaled * calib->par_h3) / 100) >> 1); var2 =3D (calib->par_h2 * @@ -567,68 +651,35 @@ static int bme680_gas_config(struct bme680_data *data) =20 static int bme680_read_temp(struct bme680_data *data, int *val) { - struct device *dev =3D regmap_get_device(data->regmap); int ret; u32 adc_temp; s16 comp_temp; =20 - ret =3D regmap_bulk_read(data->regmap, BME680_REG_TEMP_MSB, - data->buf, BME680_TEMP_NUM_BYTES); - if (ret < 0) { - dev_err(dev, "failed to read temperature\n"); + ret =3D bme680_read_temp_adc(data, &adc_temp); + if (ret) return ret; - } =20 - adc_temp =3D FIELD_GET(BME680_MEAS_TRIM_MASK, - get_unaligned_be24(data->buf)); - if (adc_temp =3D=3D BME680_MEAS_SKIPPED) { - /* reading was skipped */ - dev_err(dev, "reading temperature skipped\n"); - return -EINVAL; - } comp_temp =3D bme680_compensate_temp(data, adc_temp); - /* - * val might be NULL if we're called by the read_press/read_humid - * routine which is called to get t_fine value used in - * compensate_press/compensate_humid to get compensated - * pressure/humidity readings. - */ - if (val) { - *val =3D comp_temp * 10; /* Centidegrees to millidegrees */ - return IIO_VAL_INT; - } - - return ret; + *val =3D comp_temp * 10; /* Centidegrees to millidegrees */ + return IIO_VAL_INT; } =20 static int bme680_read_press(struct bme680_data *data, int *val, int *val2) { - struct device *dev =3D regmap_get_device(data->regmap); int ret; u32 adc_press; + s32 t_fine; =20 - /* Read and compensate temperature to get a reading of t_fine */ - ret =3D bme680_read_temp(data, NULL); - if (ret < 0) + ret =3D bme680_get_t_fine(data, &t_fine); + if (ret) return ret; =20 - ret =3D regmap_bulk_read(data->regmap, BME680_REG_PRESS_MSB, - data->buf, BME680_PRESS_NUM_BYTES); - if (ret < 0) { - dev_err(dev, "failed to read pressure\n"); + ret =3D bme680_read_press_adc(data, &adc_press); + if (ret) return ret; - } - - adc_press =3D FIELD_GET(BME680_MEAS_TRIM_MASK, - get_unaligned_be24(data->buf)); - if (adc_press =3D=3D BME680_MEAS_SKIPPED) { - /* reading was skipped */ - dev_err(dev, "reading pressure skipped\n"); - return -EINVAL; - } =20 - *val =3D bme680_compensate_press(data, adc_press); + *val =3D bme680_compensate_press(data, adc_press, t_fine); *val2 =3D 1000; return IIO_VAL_FRACTIONAL; } @@ -636,30 +687,19 @@ static int bme680_read_press(struct bme680_data *data, static int bme680_read_humid(struct bme680_data *data, int *val, int *val2) { - struct device *dev =3D regmap_get_device(data->regmap); int ret; - u16 adc_humidity; - u32 comp_humidity; + u32 adc_humidity, comp_humidity; + s32 t_fine; =20 - /* Read and compensate temperature to get a reading of t_fine */ - ret =3D bme680_read_temp(data, NULL); - if (ret < 0) + ret =3D bme680_get_t_fine(data, &t_fine); + if (ret) return ret; =20 - ret =3D regmap_bulk_read(data->regmap, BME680_REG_HUMIDITY_MSB, - &data->be16, BME680_HUMID_NUM_BYTES); - if (ret < 0) { - dev_err(dev, "failed to read humidity\n"); + ret =3D bme680_read_humid_adc(data, &adc_humidity); + if (ret) return ret; - } =20 - adc_humidity =3D be16_to_cpu(data->be16); - if (adc_humidity =3D=3D BME680_MEAS_SKIPPED) { - /* reading was skipped */ - dev_err(dev, "reading humidity skipped\n"); - return -EINVAL; - } - comp_humidity =3D bme680_compensate_humid(data, adc_humidity); + comp_humidity =3D bme680_compensate_humid(data, adc_humidity, t_fine); =20 *val =3D comp_humidity; *val2 =3D 1000; --=20 2.25.1