Received-SPF: pass (google.com: domain of linux-kernel+bounces-207550-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
From: Vasileios Amoiridis <vassilisamir@gmail.com>
To: jic23@kernel.org
Cc: dpfrey@gmail.com,
	himanshujha199640@gmail.com,
	lars@metafoo.de,
	linux-iio@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	mike.looijmans@topic.nl,
	vassilisamir@gmail.com
Subject: [PATCH v3 11/15] iio: chemical: bme680: Modify startup procedure
Date: Mon, 10 Jun 2024 01:38:22 +0200
Message-Id: <20240609233826.330516-12-vassilisamir@gmail.com>
In-Reply-To: <20240609233826.330516-1-vassilisamir@gmail.com>
References: <20240609233826.330516-1-vassilisamir@gmail.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

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 # [1]
Link: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/examples/forced_mode/forced_mode.c#L44 # [2]
Link: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/examples/forced_mode/forced_mode.c#L53 # [3]
Link: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/examples/forced_mode/forced_mode.c#L60 # [4]
Link: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/bme68x.c#L640 # [5]
Link: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/bme68x.c#L294 # [6]
Signed-off-by: Vasileios Amoiridis <vassilisamir@gmail.com>
---
 drivers/iio/chemical/bme680.h      |  2 ++
 drivers/iio/chemical/bme680_core.c | 21 ++++++++++++++-------
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/chemical/bme680.h b/drivers/iio/chemical/bme680.h
index 7d0ff294725a..b2c547ac8d34 100644
--- 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 a54460fddc91..0390c298fdd8 100644
--- 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;
 	}
 
-- 
2.25.1