iio: chemical: bme680: Modify startup procedure

Modify the startup procedure to reflect the procedure of the Bosch BME68x
Sensor API. The initial readings and configuration of the sensor need to
happen in the following order:

1) Read calibration data [1,2]
2) Chip general configuration [3]
3) Gas configuration [4]

After the chip configuration it is necessary to ensure that the sensor is
in sleeping mode, in order to apply the gas configuration settings [5].

Also, after the soft reset, it is advised to wait for 5ms [6].

Link: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/bme68x.c#L162
Link: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/examples/forced_mode/forced_mode.c#L44
Link: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/examples/forced_mode/forced_mode.c#L53
Link: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/examples/forced_mode/forced_mode.c#L60
Link: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/bme68x.c#L640
Link: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/bme68x.c#L294
Signed-off-by: Vasileios Amoiridis <vassilisamir@gmail.com>
Link: https://patch.msgid.link/20240609233826.330516-12-vassilisamir@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/chemical/bme680.h b/drivers/iio/chemical/bme680.h
index 7d0ff294725a9b420cc3a87a57c14c0ac1323ea9..b2c547ac8d34995266621487914f2cb41b25e6d5 100644 (file)
--- a/drivers/iio/chemical/bme680.h
+++ b/drivers/iio/chemical/bme680.h
@@ -63,6 +63,8 @@
 
 #define BME680_MEAS_TRIM_MASK                  GENMASK(24, 4)
 
+#define BME680_STARTUP_TIME_US                 5000
+
 /* Calibration Parameters */
 #define BME680_T2_LSB_REG      0x8A
 #define BME680_H2_MSB_REG      0xE1

diff --git a/drivers/iio/chemical/bme680_core.c b/drivers/iio/chemical/bme680_core.c
index a54460fddc918323fefa81d3847643cf5be67e6d..0390c298fdd8a7e83e38049bc8c814900629468e 100644 (file)
--- a/drivers/iio/chemical/bme680_core.c
+++ b/drivers/iio/chemical/bme680_core.c
@@ -531,6 +531,11 @@ static int bme680_gas_config(struct bme680_data *data)
        int ret;
        u8 heatr_res, heatr_dur;
 
+       /* Go to sleep */
+       ret = bme680_set_mode(data, false);
+       if (ret < 0)
+               return ret;
+
        heatr_res = bme680_calc_heater_res(data, data->heater_temp);
 
        /* set target heater temperature */
@@ -866,6 +871,8 @@ int bme680_core_probe(struct device *dev, struct regmap *regmap,
                return ret;
        }
 
+       usleep_range(BME680_STARTUP_TIME_US, BME680_STARTUP_TIME_US + 1000);
+
        ret = regmap_read(regmap, BME680_REG_CHIP_ID, &data->check);
        if (ret < 0) {
                dev_err(dev, "Error reading chip ID\n");
@@ -878,22 +885,22 @@ int bme680_core_probe(struct device *dev, struct regmap *regmap,
                return -ENODEV;
        }
 
-       ret = bme680_chip_config(data);
+       ret = bme680_read_calib(data, &data->bme680);
        if (ret < 0) {
-               dev_err(dev, "failed to set chip_config data\n");
+               dev_err(dev,
+                       "failed to read calibration coefficients at probe\n");
                return ret;
        }
 
-       ret = bme680_gas_config(data);
+       ret = bme680_chip_config(data);
        if (ret < 0) {
-               dev_err(dev, "failed to set gas config data\n");
+               dev_err(dev, "failed to set chip_config data\n");
                return ret;
        }
 
-       ret = bme680_read_calib(data, &data->bme680);
+       ret = bme680_gas_config(data);
        if (ret < 0) {
-               dev_err(dev,
-                       "failed to read calibration coefficients at probe\n");
+               dev_err(dev, "failed to set gas config data\n");
                return ret;
        }