drivers/sensors/sht3x.c: Add Sensirion SHT3x driver.

drivers/sensors/Kconfig

@@ -683,6 +683,34 @@ config SHT21_DEBUG
 
 endif # SENSORS_SHT21
 
+config SENSORS_SHT3X
+	bool "Sensirion SHT3x temperature and humidity sensor"
+	default n
+	select I2C
+	---help---
+		Enable driver support for the Sensirion SHT3x temperature
+		and humidity sensors.
+
+if SENSORS_SHT3X
+
+config SHT3X_I2C_FREQUENCY
+	int "SHT3x I2C frequency"
+	default 400000
+	range 1 400000
+
+config SHT3X_I2C_ADDR
+	hex "SHT3x I2C addr"
+	default 0x44
+	range 0x44 0x45
+
+config SHT3X_DEBUG
+	bool "Debug support for the SHT3x"
+	default n
+	---help---
+		Enables debug features for the SHT3x
+
+endif # SENSORS_SHT3X
+
 config SENSORS_SPS30
 	bool "Sensirion SPS30 particulate matter sensor"
 	default n

drivers/sensors/Make.defs

@@ -186,6 +186,10 @@ ifeq ($(CONFIG_SENSORS_SHT21),y)
   CSRCS += sht21.c
 endif
 
+ifeq ($(CONFIG_SENSORS_SHT3X),y)
+  CSRCS += sht3x.c
+endif
+
 ifeq ($(CONFIG_SENSORS_SPS30),y)
   CSRCS += sps30.c
 endif

include/nuttx/sensors/sht3x.h

@@ -0,0 +1,84 @@
+/****************************************************************************
+ * include/nuttx/sensors/sht3x.h
+ *
+ *   Copyright (C) 2019 Hexagon AB. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_NUTT_SENSORS_SHT3X_H
+#define __INCLUDE_NUTT_SENSORS_SHT3X_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/sensors/ioctl.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+struct i2c_master_s;  /* Forward reference */
+
+struct sht3x_meas_data_s
+{
+  float temperature;
+  float humidity;
+};
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: sht3x_register
+ *
+ * Description:
+ *   Register the SHT3x character device as 'devpath'
+ *
+ * Input Parameters:
+ *   devpath - The full path to the driver to register. E.g., "/dev/temp0"
+ *   i2c     - An instance of the I2C interface to use to communicate with
+ *             the SHT3x
+ *   addr    - The I2C address of the SHT3x.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+int sht3x_register(FAR const char *devpath, FAR struct i2c_master_s *i2c,
+                   uint8_t addr);
+
+#endif /* __INCLUDE_NUTT_SENSORS_SHT3X_H */