drivers: sensor: ENS210: add single shot mode

Add possibility to change the measurement modes
of the temperature and humidity measurements to
continuous or single-shot mode or switch them off.

Signed-off-by: Christian Hirsch <christian.hirsch@tuwien.ac.at>

drivers/sensor/ens210/Kconfig

@@ -10,6 +10,32 @@ menuconfig ENS210
 	  Enable driver for ENS210 Digital Temperature and Humidity sensor.
 if ENS210
 
+choice
+	prompt "Temperature measurement mode"
+	default ENS210_TEMPERATURE_CONTINUOUS
+	help
+	  Enable/disable temperature measurements and set measurement mode.
+config ENS210_TEMPERATURE_OFF
+	bool "Disable temperature measurements"
+config ENS210_TEMPERATURE_SINGLE
+	bool "Enable temperature measurements in single shot mode"
+config ENS210_TEMPERATURE_CONTINUOUS
+	bool "Enable temperature measurements in continuous mode"
+endchoice
+
+choice
+	prompt "Humidity measurement mode"
+	default ENS210_HUMIDITY_CONTINUOUS
+	help
+	  Enable/disable relative humidity measurements and set measurement mode.
+config ENS210_HUMIDITY_OFF
+	bool "Disable relative humidity measurements"
+config ENS210_HUMIDITY_SINGLE
+	bool "Enable relative humidity measurements in single shot mode"
+config ENS210_HUMIDITY_CONTINUOUS
+	bool "Enable relative humidity measurements in continuous mode"
+endchoice
+
 config ENS210_CRC_CHECK
 	bool "Enable CRC Check"
 	default y

drivers/sensor/ens210/ens210.c

@@ -36,6 +36,46 @@ static u32_t ens210_crc7(u32_t bitstream)
 }
 #endif /* CONFIG_ENS210_CRC_CHECK */
 
+#if defined(CONFIG_ENS210_TEMPERATURE_SINGLE) \
+		|| defined(CONFIG_ENS210_HUMIDITY_SINGLE)
+static int ens210_measure(struct device *i2c_dev, enum sensor_channel chan)
+{
+	u8_t buf;
+	int ret;
+	const struct ens210_sens_start sense_start = {
+		.t_start = ENS210_T_START && (chan == SENSOR_CHAN_ALL
+				|| chan == SENSOR_CHAN_AMBIENT_TEMP),
+		.h_start = ENS210_H_START && (chan == SENSOR_CHAN_ALL
+				|| chan == SENSOR_CHAN_HUMIDITY)
+	};
+
+	/* Start measuring */
+	ret = i2c_reg_write_byte(i2c_dev,
+			DT_INST_0_AMS_ENS210_BASE_ADDRESS,
+			ENS210_REG_SENS_START, *(u8_t *)&sense_start);
+
+	if (ret < 0) {
+		LOG_ERR("Failed to set SENS_START to 0x%x",
+				*(u8_t *)&sense_start);
+		return -EIO;
+	}
+
+	/* Wait for measurement to be completed */
+	do {
+		k_sleep(K_MSEC(2));
+		ret = i2c_reg_read_byte(i2c_dev,
+				DT_INST_0_AMS_ENS210_BASE_ADDRESS,
+				ENS210_REG_SENS_START, &buf);
+
+		if (ret < 0) {
+			LOG_ERR("Failed to read SENS_STAT");
+		}
+	} while (buf & *(u8_t *)&sense_start);
+
+	return ret;
+}
+#endif /* Single shot mode */
+
 static int ens210_sample_fetch(struct device *dev, enum sensor_channel chan)
 {
 	struct ens210_data *drv_data = dev->driver_data;
@@ -46,7 +86,18 @@ static int ens210_sample_fetch(struct device *dev, enum sensor_channel chan)
 	u32_t temp_valid, humidity_valid;
 #endif /* CONFIG_ENS210_CRC_CHECK */
 
-	__ASSERT_NO_MSG(chan == SENSOR_CHAN_ALL);
+	__ASSERT_NO_MSG(chan == SENSOR_CHAN_ALL
+			|| chan == SENSOR_CHAN_AMBIENT_TEMP
+			|| chan == SENSOR_CHAN_HUMIDITY);
+
+#if defined(CONFIG_ENS210_TEMPERATURE_SINGLE) \
+		|| defined(CONFIG_ENS210_HUMIDITY_SINGLE)
+	ret = ens210_measure(drv_data->i2c, chan);
+	if (ret < 0) {
+		LOG_ERR("Failed to measure");
+		return ret;
+	}
+#endif /* Single shot mode */
 
 	for (cnt = 0; cnt <= CONFIG_ENS210_MAX_READ_RETRIES; cnt++) {
 		ret =  i2c_burst_read(drv_data->i2c, DT_INST_0_AMS_ENS210_BASE_ADDRESS,
@@ -56,35 +107,47 @@ static int ens210_sample_fetch(struct device *dev, enum sensor_channel chan)
 			continue;
 		}
 
-		if (!data[0].valid) {
+		/* Get temperature value */
-			LOG_WRN("Temperature not valid");
+		if (chan == SENSOR_CHAN_ALL || chan == SENSOR_CHAN_AMBIENT_TEMP) {
-			continue;
-		}
 
-		if (!data[1].valid) {
+			if (!data[0].valid) {
-			LOG_WRN("Humidity not valid");
+				LOG_WRN("Temperature not valid");
-			continue;
+				continue;
-		}
+			}
 
 #ifdef CONFIG_ENS210_CRC_CHECK
-		temp_valid =      data[0].val |
+			temp_valid = data[0].val |
-				  (data[0].valid << (sizeof(data[0].val) * 8));
+					(data[0].valid << (sizeof(data[0].val) * 8));
-		humidity_valid =  data[1].val |
-				  (data[1].valid << (sizeof(data[1].val) * 8));
 
-		if (ens210_crc7(temp_valid) != data[0].crc7) {
+			if (ens210_crc7(temp_valid) != data[0].crc7) {
-			LOG_WRN("Temperature CRC error");
+				LOG_WRN("Temperature CRC error");
-			continue;
+				continue;
-		}
+			}
-
-		if (ens210_crc7(humidity_valid) != data[1].crc7) {
-			LOG_WRN("Humidity CRC error");
-			continue;
-		}
 #endif /* CONFIG_ENS210_CRC_CHECK */
 
-		drv_data->temp = data[0];
+			drv_data->temp = data[0];
-		drv_data->humidity = data[1];
+		}
+
+		/* Get humidity value */
+		if (chan == SENSOR_CHAN_ALL || chan == SENSOR_CHAN_HUMIDITY) {
+
+			if (!data[1].valid) {
+				LOG_WRN("Humidity not valid");
+				continue;
+			}
+
+#ifdef CONFIG_ENS210_CRC_CHECK
+			humidity_valid = data[1].val |
+					  (data[1].valid << (sizeof(data[1].val) * 8));
+
+			if (ens210_crc7(humidity_valid) != data[1].crc7) {
+				LOG_WRN("Humidity CRC error");
+				continue;
+			}
+#endif /* CONFIG_ENS210_CRC_CHECK */
+
+			drv_data->humidity = data[1];
+		}
 
 		return 0;
 	}
@@ -125,7 +188,10 @@ static int ens210_channel_get(struct device *dev,
 
 static int ens210_sys_reset(struct device *i2c_dev)
 {
-	const struct ens210_sys_ctrl sys_ctrl = {.low_power = 0, .reset = 1};
+	const struct ens210_sys_ctrl sys_ctrl = {
+			.low_power = 0,
+			.reset = 1
+	};
 	int ret;
 
 	ret = i2c_reg_write_byte(i2c_dev, DT_INST_0_AMS_ENS210_BASE_ADDRESS,
@@ -136,9 +202,12 @@ static int ens210_sys_reset(struct device *i2c_dev)
 	return ret;
 }
 
-static int ens210_sys_enable(struct device *i2c_dev)
+static int ens210_sys_enable(struct device *i2c_dev, u8_t low_power)
 {
-	const struct ens210_sys_ctrl sys_ctrl = {.low_power = 0, .reset = 0};
+	const struct ens210_sys_ctrl sys_ctrl = {
+			.low_power = low_power,
+			.reset = 0
+	};
 	int ret;
 
 	ret = i2c_reg_write_byte(i2c_dev, DT_INST_0_AMS_ENS210_BASE_ADDRESS,
@@ -173,7 +242,7 @@ static int ens210_wait_boot(struct device *i2c_dev)
 			ens210_sys_reset(i2c_dev);
 		}
 
-		ens210_sys_enable(i2c_dev);
+		ens210_sys_enable(i2c_dev, 0);
 
 		k_sleep(K_MSEC(2));
 	}
@@ -196,13 +265,18 @@ static int ens210_init(struct device *dev)
 {
 	struct ens210_data *drv_data = dev->driver_data;
 	const struct ens210_sens_run sense_run = {
-		.t_run = 1,
+		.t_run = ENS210_T_RUN,
-		.h_run = 1
+		.h_run = ENS210_H_RUN
 	};
+
+#if defined(CONFIG_ENS210_TEMPERATURE_CONTINUOUS) \
+	|| defined(CONFIG_ENS210_HUMIDITY_CONTINUOUS)
 	const struct ens210_sens_start sense_start = {
-		.t_start = 1,
+		.t_start = ENS210_T_RUN,
-		.h_start = 1
+		.h_start = ENS210_H_RUN
 	};
+#endif
+
 	int ret;
 	u16_t part_id;
 
@@ -219,7 +293,9 @@ static int ens210_init(struct device *dev)
 		return -EIO;
 	}
 
-	/* Check Hardware ID. This is only possible after device is ready */
+	/* Check Hardware ID. This is only possible after device is ready
+	 * and active
+	 */
 	ret =  i2c_burst_read(drv_data->i2c, DT_INST_0_AMS_ENS210_BASE_ADDRESS,
 			      ENS210_REG_PART_ID, (u8_t *)&part_id,
 			      sizeof(part_id));
@@ -234,7 +310,12 @@ static int ens210_init(struct device *dev)
 		return -EIO;
 	}
 
-	/* Set continuous measurement */
+	/* Enable low power mode */
+	if ((ENS210_T_RUN | ENS210_H_RUN) == 0) {
+		ens210_sys_enable(drv_data->i2c, 1);
+	}
+
+	/* Set measurement mode*/
 	ret = i2c_reg_write_byte(drv_data->i2c, DT_INST_0_AMS_ENS210_BASE_ADDRESS,
 				 ENS210_REG_SENS_RUN, *(u8_t *)&sense_run);
 	if (ret < 0) {
@@ -243,6 +324,8 @@ static int ens210_init(struct device *dev)
 		return -EIO;
 	}
 
+#if defined(CONFIG_ENS210_TEMPERATURE_CONTINUOUS) \
+	|| defined(CONFIG_ENS210_HUMIDITY_CONTINUOUS)
 	/* Start measuring */
 	ret = i2c_reg_write_byte(drv_data->i2c, DT_INST_0_AMS_ENS210_BASE_ADDRESS,
 				 ENS210_REG_SENS_START, *(u8_t *)&sense_start);
@@ -251,6 +334,7 @@ static int ens210_init(struct device *dev)
 			    *(u8_t *)&sense_start);
 		return -EIO;
 	}
+#endif
 	return 0;
 }
 

drivers/sensor/ens210/ens210.h

@@ -25,6 +25,28 @@
 
 #define ENS210_PART_ID 0x0210
 
+#if defined CONFIG_ENS210_TEMPERATURE_OFF
+#define ENS210_T_RUN   0
+#define ENS210_T_START 0
+#elif defined CONFIG_ENS210_TEMPERATURE_SINGLE
+#define ENS210_T_RUN   0
+#define ENS210_T_START 1
+#elif defined CONFIG_ENS210_TEMPERATURE_CONTINUOUS
+#define ENS210_T_RUN   1
+#define ENS210_T_START 1
+#endif
+
+#if defined CONFIG_ENS210_HUMIDITY_OFF
+#define ENS210_H_RUN   0
+#define ENS210_H_START 0
+#elif defined CONFIG_ENS210_HUMIDITY_SINGLE
+#define ENS210_H_RUN   0
+#define ENS210_H_START 1
+#elif defined CONFIG_ENS210_HUMIDITY_CONTINUOUS
+#define ENS210_H_RUN   1
+#define ENS210_H_START 1
+#endif
+
 /*
  * Polynomial
  * 0b 1000 1001 ~ x^7+x^3+x^0