drivers: sensors: Add Si7006 temperature/humidity sensor driver

Adds driver for Silicon Labs Si7006 chip.

Signed-off-by: Vaishali Pathak <vaishali@electronut.in>

drivers/sensor/CMakeLists.txt

@@ -48,6 +48,7 @@ add_subdirectory_ifdef(CONFIG_PMS7003		pms7003)
 add_subdirectory_ifdef(CONFIG_QDEC_NRFX		qdec_nrfx)
 add_subdirectory_ifdef(CONFIG_TEMP_NRF5		nrf5)
 add_subdirectory_ifdef(CONFIG_SHT3XD		sht3xd)
+add_subdirectory_ifdef(CONFIG_SI7006		si7006)
 add_subdirectory_ifdef(CONFIG_STTS751		stts751)
 add_subdirectory_ifdef(CONFIG_SX9500		sx9500)
 add_subdirectory_ifdef(CONFIG_TH02		    th02)

drivers/sensor/Kconfig

@@ -121,6 +121,8 @@ source "drivers/sensor/qdec_nrfx/Kconfig"
 
 source "drivers/sensor/sht3xd/Kconfig"
 
+source "drivers/sensor/si7006/Kconfig"
+
 source "drivers/sensor/stts751/Kconfig"
 
 source "drivers/sensor/sx9500/Kconfig"

drivers/sensor/si7006/CMakeLists.txt

@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: Apache-2.0
+
+ zephyr_library()
+
+zephyr_library_sources_ifdef(CONFIG_SI7006 si7006.c)

drivers/sensor/si7006/Kconfig

@@ -0,0 +1,11 @@
+#
+# Copyright (c) 2019 Electronut Labs
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+config SI7006
+	bool "Si7006 Temperature and Humidity Sensor"
+	depends on (I2C && HAS_DTS_I2C)
+	help
+	  Enable I2C-based driver for Si7006 Temperature and Humidity Sensor.

drivers/sensor/si7006/si7006.c

@@ -0,0 +1,162 @@
+/*
+ * Copyright (c) 2019 Electronut Labs
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <sensor.h>
+#include <kernel.h>
+#include <device.h>
+#include <init.h>
+#include <string.h>
+#include <sys/byteorder.h>
+#include <sys/__assert.h>
+#include <logging/log.h>
+#include <i2c.h>
+#include <logging/log.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "si7006.h"
+
+LOG_MODULE_REGISTER(si7006, CONFIG_SENSOR_LOG_LEVEL);
+
+struct si7006_data {
+	struct device *i2c_dev;
+	u16_t temperature;
+	u16_t humidity;
+};
+
+/**
+ * @brief function to get relative humidity
+ *
+ * @return int 0 on success
+ */
+static int si7006_get_humidity(struct device *i2c_dev,
+			       struct si7006_data *si_data)
+{
+	int retval;
+	u8_t hum[2];
+
+	retval = i2c_burst_read(i2c_dev, DT_INST_0_SILABS_SI7006_BASE_ADDRESS,
+		SI7006_MEAS_REL_HUMIDITY_MASTER_MODE, hum, sizeof(hum));
+
+	if (retval == 0) {
+		si_data->humidity = (hum[0] << 8) | hum[1];
+	} else {
+		LOG_ERR("read register err");
+	}
+
+	return retval;
+}
+
+/**
+ * @brief function to get temperature
+ *
+ * @return int 0 on success
+ */
+
+static int si7006_get_temperature(struct device *i2c_dev,
+				  struct si7006_data *si_data)
+{
+	u8_t temp[2];
+	int retval;
+
+	retval = i2c_burst_read(i2c_dev, DT_INST_0_SILABS_SI7006_BASE_ADDRESS,
+		SI7006_MEAS_TEMP_MASTER_MODE, temp, sizeof(temp));
+
+	if (retval == 0) {
+		si_data->temperature = (temp[0] << 8) | temp[1];
+	} else {
+		LOG_ERR("read register err");
+	}
+
+	return retval;
+}
+
+/**
+ * @brief fetch a sample from the sensor
+ *
+ * @return 0
+ */
+static int si7006_sample_fetch(struct device *dev, enum sensor_channel chan)
+{
+	int retval;
+	struct si7006_data *si_data = dev->driver_data;
+
+	retval = si7006_get_temperature(si_data->i2c_dev, si_data);
+	if (retval == 0) {
+		retval = si7006_get_humidity(si_data->i2c_dev, si_data);
+	}
+
+	return retval;
+}
+
+/**
+ * @brief sensor value get
+ *
+ * @return -ENOTSUP for unsupported channels
+ */
+static int si7006_channel_get(struct device *dev, enum sensor_channel chan,
+			      struct sensor_value *val)
+{
+	struct si7006_data *si_data = dev->driver_data;
+
+	if (chan == SENSOR_CHAN_AMBIENT_TEMP) {
+
+		s32_t temp_ucelcius = ((17572 * (s32_t)si_data->temperature)
+				       / 65536) * 10000;
+
+		val->val1 = temp_ucelcius / 1000000;
+		val->val2 = temp_ucelcius % 1000000;
+
+		LOG_DBG("temperature = val1:%d, val2:%d", val->val1, val->val2);
+
+		return 0;
+	} else if (chan == SENSOR_CHAN_HUMIDITY) {
+
+		s32_t relative_humidity = (((125 * (s32_t)si_data->humidity)
+					    / 65536) - 6) * 1000000;
+
+		val->val1 = relative_humidity / 1000000;
+		val->val2 = relative_humidity % 1000000;
+
+		LOG_DBG("humidity = val1:%d, val2:%d", val->val1, val->val2);
+
+		return 0;
+	} else {
+		return -ENOTSUP;
+	}
+}
+
+static const struct sensor_driver_api si7006_api = {
+	.sample_fetch = &si7006_sample_fetch,
+	.channel_get = &si7006_channel_get,
+};
+
+/**
+ * @brief initiasize the sensor
+ *
+ * @return 0 for success
+ */
+
+static int si7006_init(struct device *dev)
+{
+	struct si7006_data *drv_data = dev->driver_data;
+
+	drv_data->i2c_dev = device_get_binding(
+		DT_INST_0_SILABS_SI7006_BUS_NAME);
+
+	if (!drv_data->i2c_dev) {
+		LOG_ERR("i2c master not found.");
+		return -EINVAL;
+	}
+
+	LOG_DBG("si7006 init ok");
+
+	return 0;
+}
+
+static struct si7006_data si_data;
+
+DEVICE_AND_API_INIT(si7006, DT_INST_0_SILABS_SI7006_LABEL, si7006_init,
+	&si_data, NULL, POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY, &si7006_api);

drivers/sensor/si7006/si7006.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2019 Electronut Labs
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef _SI7006_H
+#define _SI7006_H
+
+/* Si7006 register addresses */
+#define SI7006_MEAS_REL_HUMIDITY_MASTER_MODE            0xE5
+#define SI7006_MEAS_REL_HUMIDITY_NO_MASTER_MODE         0xF5
+#define SI7006_MEAS_TEMP_MASTER_MODE                    0xE3
+#define SI7006_MEAS_TEMP_NO_MASTER_MODE                 0xF3
+#define SI7006_READ_OLD_TEMP                            0xE0
+#define SI7006_RESET                                    0xFE
+#define SI7006_WRITE_HUMIDITY_TEMP_CONTR                0xE6
+#define SI7006_READ_HUMIDITY_TEMP_CONTR                 0xE7
+#define SI7006_WRITE_HEATER_CONTR                       0x51
+#define SI7006_READ_HEATER_CONTR                        0x11
+#define SI7006_READ_ID_LOW_0                            0xFA
+#define SI7006_READ_ID_LOW_1                            0x0F
+#define SI7006_READ_ID_HIGH_0                           0xFC
+#define SI7006_READ_ID_HIGH_1                           0xC9
+#define SI7006_FIRMWARE_0                               0x84
+#define SI7006_FIRMWARE_1                               0xB8
+
+#endif /* _SI7006_H */

dts/bindings/sensor/silabs,si7006.yaml

@@ -0,0 +1,18 @@
+#
+# Copyright (c) 2019, Electronut Labs
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+---
+title: Si7006 Temperature and Humidity sensor
+version: 0.1
+
+description: >
+    This is a representation of Si7006 Temperature and Humidity sensor
+
+inherits:
+    !include i2c-device.yaml
+
+properties:
+    compatible:
+      constraint: "silabs,si7006"

tests/drivers/build_all/dts_fixup.h

@@ -166,6 +166,12 @@
 #define DT_INST_0_SENSIRION_SHT3XD_BUS_NAME ""
 #endif
 
+#ifndef DT_INST_0_SILABS_SI7006_LABEL
+#define DT_INST_0_SILABS_SI7006_LABEL ""
+#define DT_INST_0_SILABS_SI7006_BASE_ADDRESS 0x40
+#define DT_INST_0_SILABS_SI7006_BUS_NAME	""
+#endif
+
 #ifndef DT_INST_0_ST_LIS2DS12_LABEL
 #define DT_INST_0_ST_LIS2DS12_LABEL ""
 #define DT_INST_0_ST_LIS2DS12_BUS_NAME ""

tests/drivers/build_all/sensors_i_z.conf

@@ -24,6 +24,7 @@ CONFIG_MAX44009=y
 CONFIG_MCP9808=y
 CONFIG_MPU6050=y
 CONFIG_SHT3XD=y
+CONFIG_SI7006=y
 CONFIG_SX9500=y
 CONFIG_TEMP_NRF5=y
 CONFIG_TH02=y