iio: chemical: bme680: Move forced mode setup in ->read_raw()

Whenever the sensor is set to forced mode, a TPHG cycle is triggered and
the values of temperature, pressure, humidity and gas become ready to be
read.

The setup of the forced mode to trigger measurements was located inside
the read_{temp/gas}() functions. This was not posing a functional problem
since read_{humid/press}() are internally calling read_temp() so the
forced mode is set through this call.

This is not very clear and it is kind of hidden that regardless of the
measurement, the setup of the forced mode needs to happen before any
measurement.
Signed-off-by: Vasileios Amoiridis <vassilisamir@gmail.com>
Link: https://patch.msgid.link/20240609233826.330516-15-vassilisamir@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/chemical/bme680_core.c

@@ -572,15 +572,6 @@ static int bme680_read_temp(struct bme680_data *data, int *val)
 	u32 adc_temp;
 	s16 comp_temp;
 
-	/* set forced mode to trigger measurement */
-	ret = bme680_set_mode(data, true);
-	if (ret < 0)
-		return ret;
-
-	ret = bme680_wait_for_eoc(data);
-	if (ret)
-		return ret;
-
 	ret = regmap_bulk_read(data->regmap, BME680_REG_TEMP_MSB,
 			       data->buf, BME680_TEMP_NUM_BYTES);
 	if (ret < 0) {
@@ -683,15 +674,6 @@ static int bme680_read_gas(struct bme680_data *data,
 	u16 adc_gas_res, gas_regs_val;
 	u8 gas_range;
 
-	/* set forced mode to trigger measurement */
-	ret = bme680_set_mode(data, true);
-	if (ret < 0)
-		return ret;
-
-	ret = bme680_wait_for_eoc(data);
-	if (ret)
-		return ret;
-
 	ret = regmap_read(data->regmap, BME680_REG_MEAS_STAT_0, &data->check);
 	if (data->check & BME680_GAS_MEAS_BIT) {
 		dev_err(dev, "gas measurement incomplete\n");
@@ -730,9 +712,19 @@ static int bme680_read_raw(struct iio_dev *indio_dev,
 			   int *val, int *val2, long mask)
 {
 	struct bme680_data *data = iio_priv(indio_dev);
+	int ret;
 
 	guard(mutex)(&data->lock);
 
+	/* set forced mode to trigger measurement */
+	ret = bme680_set_mode(data, true);
+	if (ret < 0)
+		return ret;
+
+	ret = bme680_wait_for_eoc(data);
+	if (ret)
+		return ret;
+
 	switch (mask) {
 	case IIO_CHAN_INFO_PROCESSED:
 		switch (chan->type) {