drivers: add support for TeraRanger Evo

This commit adds i2c support for TeraRanger Evo sensor
by Terabee

Signed-off-by: Mateusz Sadowski <msadowski90@gmail.com>

ROMFS/px4fmu_common/init.d/rc.sensors

@@ -321,6 +321,12 @@ then
 	mb12xx start
 fi
 
+# teraranger evo tof sensor
+if param compare SENS_EN_TREVO 1
+then
+	trevo start
+fi
+
 # teraranger one tof sensor
 if param compare SENS_EN_TRONE 1
 then

cmake/configs/nuttx_aerocore2_default.cmake

@@ -20,6 +20,7 @@ set(config_module_list
 	drivers/lsm303d
 	drivers/l3gd20
 	drivers/ms5611
+	drivers/trevo
 	drivers/trone
 	drivers/gps
 	drivers/pwm_out_sim

cmake/configs/nuttx_auav-x21_default.cmake

@@ -28,6 +28,7 @@ set(config_module_list
 	drivers/sf0x
 	drivers/sf1xx
 	drivers/ll40ls
+	drivers/trevo
 	drivers/trone
 	drivers/gps
 	drivers/pwm_out_sim

cmake/configs/nuttx_mindpx-v2_default.cmake

@@ -31,6 +31,7 @@ set(config_module_list
 	drivers/sf0x
 	drivers/sf1xx
 	drivers/ll40ls
+	drivers/trevo
 	drivers/trone
 	drivers/gps
 	drivers/pwm_out_sim

cmake/configs/nuttx_px4fmu-v2_default.cmake

@@ -29,6 +29,7 @@ set(config_module_list
 	#drivers/srf02
 	drivers/sf0x
 	drivers/ll40ls
+	drivers/trevo
 	drivers/trone
 	drivers/gps
 	drivers/pwm_out_sim

cmake/configs/nuttx_px4fmu-v2_test.cmake

@@ -29,6 +29,7 @@ set(config_module_list
 	#drivers/srf02
 	#drivers/sf0x
 	#drivers/ll40ls
+	#drivers/trevo
 	#drivers/trone
 	drivers/gps
 	#drivers/pwm_out_sim

cmake/configs/nuttx_px4fmu-v3_default.cmake

@@ -54,6 +54,7 @@ set(config_module_list
 	drivers/stm32/adc
 	drivers/stm32/tone_alarm
 	drivers/tap_esc
+	drivers/trevo
 	drivers/trone
 	drivers/vmount
 	modules/sensors

cmake/configs/nuttx_px4fmu-v4_default.cmake

@@ -55,6 +55,7 @@ set(config_module_list
 	drivers/stm32/adc
 	drivers/stm32/tone_alarm
 	drivers/tap_esc
+	drivers/trevo
 	drivers/trone
 	drivers/vmount
 	modules/sensors

cmake/configs/nuttx_px4fmu-v4pro_default.cmake

@@ -55,6 +55,7 @@ set(config_module_list
 	drivers/stm32/adc
 	drivers/stm32/tone_alarm
 	drivers/tap_esc
+	drivers/trevo
 	drivers/trone
 	drivers/vmount
 	modules/sensors

cmake/configs/nuttx_px4fmu-v5_default.cmake

@@ -55,6 +55,7 @@ set(config_module_list
 	drivers/stm32/adc
 	drivers/stm32/tone_alarm
 	drivers/tap_esc
+	drivers/trevo
 	drivers/trone
 	drivers/vmount
 	modules/sensors

cmake/configs/nuttx_px4nucleoF767ZI-v1_default.cmake

@@ -50,6 +50,7 @@ set(config_module_list
 	drivers/stm32/adc
 	drivers/stm32/tone_alarm
 	drivers/tap_esc
+	drivers/trevo
 	drivers/trone
 	modules/sensors
 

src/drivers/trevo/CMakeLists.txt

@@ -0,0 +1,43 @@
+############################################################################
+#
+#   Copyright (c) 2015 PX4 Development Team. 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 PX4 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.
+#
+############################################################################
+px4_add_module(
+	MODULE drivers__trevo
+	MAIN trevo
+	STACK_MAIN 1200
+	COMPILE_FLAGS
+	SRCS
+		trevo.cpp
+	DEPENDS
+		platforms__common
+	)
+# vim: set noet ft=cmake fenc=utf-8 ff=unix :

src/drivers/trevo/trevo.cpp

@@ -0,0 +1,938 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2013-2015 PX4 Development Team. 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 PX4 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.
+ *
+ ****************************************************************************/
+
+/**
+ * @file trevo.cpp
+ * @author Mateusz Sadowski
+ *
+ * Driver for the TeraRanger Evo range finders connected via I2C.
+ */
+
+#include <px4_config.h>
+#include <px4_defines.h>
+
+#include <drivers/device/i2c.h>
+
+#include <sys/types.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <semaphore.h>
+#include <string.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <errno.h>
+#include <stdio.h>
+#include <math.h>
+#include <unistd.h>
+
+#include <nuttx/arch.h>
+#include <nuttx/wqueue.h>
+#include <nuttx/clock.h>
+
+#include <systemlib/perf_counter.h>
+#include <systemlib/err.h>
+
+#include <drivers/drv_hrt.h>
+#include <drivers/drv_range_finder.h>
+#include <drivers/device/ringbuffer.h>
+
+#include <uORB/uORB.h>
+#include <uORB/topics/subsystem_info.h>
+#include <uORB/topics/distance_sensor.h>
+
+#include <board_config.h>
+
+/* Configuration Constants */
+#define TREVO_BUS           PX4_I2C_BUS_EXPANSION
+#define TREVO_BASEADDR      0x31 /* 7-bit address */
+#define TREVO_DEVICE_PATH   	"/dev/trevo"
+
+/* TREVO Registers addresses */
+
+#define TREVO_MEASURE_REG	0x00		/* Measure range register */
+#define TREVO_WHO_AM_I_REG  0x01        /* Who am I test register */
+#define TREVO_WHO_AM_I_REG_VAL 0xA1
+
+
+/* Device limits */
+#define TREVO_MIN_DISTANCE (0.50f)
+#define TREVO_MAX_DISTANCE (60.00f)
+
+#define TREVO_CONVERSION_INTERVAL 50000 /* 50ms */
+
+#ifndef CONFIG_SCHED_WORKQUEUE
+# error This requires CONFIG_SCHED_WORKQUEUE.
+#endif
+
+class TREVO : public device::I2C
+{
+public:
+	TREVO(int bus = TREVO_BUS, int address = TREVO_BASEADDR);
+	virtual ~TREVO();
+
+	virtual int 		init();
+
+	virtual ssize_t		read(struct file *filp, char *buffer, size_t buflen);
+	virtual int			ioctl(struct file *filp, int cmd, unsigned long arg);
+
+	/**
+	* Diagnostics - print some basic information about the driver.
+	*/
+	void				print_info();
+
+protected:
+	virtual int			probe();
+
+private:
+	float				_min_distance;
+	float				_max_distance;
+	work_s				_work;
+	ringbuffer::RingBuffer		*_reports;
+	bool				_sensor_ok;
+	uint8_t				_valid;
+	int					_measure_ticks;
+	bool				_collect_phase;
+	int				_class_instance;
+	int				_orb_class_instance;
+
+	orb_advert_t		_distance_sensor_topic;
+
+	perf_counter_t		_sample_perf;
+	perf_counter_t		_comms_errors;
+	perf_counter_t		_buffer_overflows;
+
+	/**
+	* Test whether the device supported by the driver is present at a
+	* specific address.
+	*
+	* @param address	The I2C bus address to probe.
+	* @return		True if the device is present.
+	*/
+	int					probe_address(uint8_t address);
+
+	/**
+	* Initialise the automatic measurement state machine and start it.
+	*
+	* @note This function is called at open and error time.  It might make sense
+	*       to make it more aggressive about resetting the bus in case of errors.
+	*/
+	void				start();
+
+	/**
+	* Stop the automatic measurement state machine.
+	*/
+	void				stop();
+
+	/**
+	* Set the min and max distance thresholds if you want the end points of the sensors
+	* range to be brought in at all, otherwise it will use the defaults TREVO_MIN_DISTANCE
+	* and TREVO_MAX_DISTANCE
+	*/
+	void				set_minimum_distance(float min);
+	void				set_maximum_distance(float max);
+	float				get_minimum_distance();
+	float				get_maximum_distance();
+
+	/**
+	* Perform a poll cycle; collect from the previous measurement
+	* and start a new one.
+	*/
+	void				cycle();
+	int					measure();
+	int					collect();
+	/**
+	* Static trampoline from the workq context; because we don't have a
+	* generic workq wrapper yet.
+	*
+	* @param arg		Instance pointer for the driver that is polling.
+	*/
+	static void		cycle_trampoline(void *arg);
+
+
+};
+
+static const uint8_t crc_table[] = {
+	0x00, 0x07, 0x0e, 0x09, 0x1c, 0x1b, 0x12, 0x15, 0x38, 0x3f, 0x36, 0x31,
+	0x24, 0x23, 0x2a, 0x2d, 0x70, 0x77, 0x7e, 0x79, 0x6c, 0x6b, 0x62, 0x65,
+	0x48, 0x4f, 0x46, 0x41, 0x54, 0x53, 0x5a, 0x5d, 0xe0, 0xe7, 0xee, 0xe9,
+	0xfc, 0xfb, 0xf2, 0xf5, 0xd8, 0xdf, 0xd6, 0xd1, 0xc4, 0xc3, 0xca, 0xcd,
+	0x90, 0x97, 0x9e, 0x99, 0x8c, 0x8b, 0x82, 0x85, 0xa8, 0xaf, 0xa6, 0xa1,
+	0xb4, 0xb3, 0xba, 0xbd, 0xc7, 0xc0, 0xc9, 0xce, 0xdb, 0xdc, 0xd5, 0xd2,
+	0xff, 0xf8, 0xf1, 0xf6, 0xe3, 0xe4, 0xed, 0xea, 0xb7, 0xb0, 0xb9, 0xbe,
+	0xab, 0xac, 0xa5, 0xa2, 0x8f, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9d, 0x9a,
+	0x27, 0x20, 0x29, 0x2e, 0x3b, 0x3c, 0x35, 0x32, 0x1f, 0x18, 0x11, 0x16,
+	0x03, 0x04, 0x0d, 0x0a, 0x57, 0x50, 0x59, 0x5e, 0x4b, 0x4c, 0x45, 0x42,
+	0x6f, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7d, 0x7a, 0x89, 0x8e, 0x87, 0x80,
+	0x95, 0x92, 0x9b, 0x9c, 0xb1, 0xb6, 0xbf, 0xb8, 0xad, 0xaa, 0xa3, 0xa4,
+	0xf9, 0xfe, 0xf7, 0xf0, 0xe5, 0xe2, 0xeb, 0xec, 0xc1, 0xc6, 0xcf, 0xc8,
+	0xdd, 0xda, 0xd3, 0xd4, 0x69, 0x6e, 0x67, 0x60, 0x75, 0x72, 0x7b, 0x7c,
+	0x51, 0x56, 0x5f, 0x58, 0x4d, 0x4a, 0x43, 0x44, 0x19, 0x1e, 0x17, 0x10,
+	0x05, 0x02, 0x0b, 0x0c, 0x21, 0x26, 0x2f, 0x28, 0x3d, 0x3a, 0x33, 0x34,
+	0x4e, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5c, 0x5b, 0x76, 0x71, 0x78, 0x7f,
+	0x6a, 0x6d, 0x64, 0x63, 0x3e, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2c, 0x2b,
+	0x06, 0x01, 0x08, 0x0f, 0x1a, 0x1d, 0x14, 0x13, 0xae, 0xa9, 0xa0, 0xa7,
+	0xb2, 0xb5, 0xbc, 0xbb, 0x96, 0x91, 0x98, 0x9f, 0x8a, 0x8d, 0x84, 0x83,
+	0xde, 0xd9, 0xd0, 0xd7, 0xc2, 0xc5, 0xcc, 0xcb, 0xe6, 0xe1, 0xe8, 0xef,
+	0xfa, 0xfd, 0xf4, 0xf3
+};
+
+static uint8_t crc8(uint8_t *p, uint8_t len)
+{
+	uint16_t i;
+	uint16_t crc = 0x0;
+
+	while (len--) {
+		i = (crc ^ *p++) & 0xFF;
+		crc = (crc_table[i] ^ (crc << 8)) & 0xFF;
+	}
+
+	return crc & 0xFF;
+}
+
+/*
+ * Driver 'main' command.
+ */
+extern "C" __EXPORT int trevo_main(int argc, char *argv[]);
+
+TREVO::TREVO(int bus, int address) :
+	I2C("TREVO", TREVO_DEVICE_PATH, bus, address, 100000),
+	_min_distance(TREVO_MIN_DISTANCE),
+	_max_distance(TREVO_MAX_DISTANCE),
+	_reports(nullptr),
+	_sensor_ok(false),
+	_valid(0),
+	_measure_ticks(0),
+	_collect_phase(false),
+	_class_instance(-1),
+	_orb_class_instance(-1),
+	_distance_sensor_topic(nullptr),
+	_sample_perf(perf_alloc(PC_ELAPSED, "tr1_read")),
+	_comms_errors(perf_alloc(PC_COUNT, "tr1_com_err")),
+	_buffer_overflows(perf_alloc(PC_COUNT, "tr1_buf_of"))
+{
+	// up the retries since the device misses the first measure attempts
+	I2C::_retries = 3;
+
+	// enable debug() calls
+	_debug_enabled = false;
+
+	// work_cancel in the dtor will explode if we don't do this...
+	memset(&_work, 0, sizeof(_work));
+}
+
+TREVO::~TREVO()
+{
+	/* make sure we are truly inactive */
+	stop();
+
+	/* free any existing reports */
+	if (_reports != nullptr) {
+		delete _reports;
+	}
+
+	if (_class_instance != -1) {
+		unregister_class_devname(RANGE_FINDER_BASE_DEVICE_PATH, _class_instance);
+	}
+
+	// free perf counters
+	perf_free(_sample_perf);
+	perf_free(_comms_errors);
+	perf_free(_buffer_overflows);
+}
+
+int
+TREVO::init()
+{
+	int ret = PX4_ERROR;
+
+	/* do I2C init (and probe) first */
+	if (I2C::init() != OK) {
+		goto out;
+	}
+
+	/* allocate basic report buffers */
+	_reports = new ringbuffer::RingBuffer(2, sizeof(distance_sensor_s));
+
+	if (_reports == nullptr) {
+		goto out;
+	}
+
+	_class_instance = register_class_devname(RANGE_FINDER_BASE_DEVICE_PATH);
+
+	if (_class_instance == CLASS_DEVICE_PRIMARY) {
+		/* get a publish handle on the range finder topic */
+		struct distance_sensor_s ds_report;
+		measure();
+		_reports->get(&ds_report);
+
+		_distance_sensor_topic = orb_advertise_multi(ORB_ID(distance_sensor), &ds_report,
+					 &_orb_class_instance, ORB_PRIO_LOW);
+
+		if (_distance_sensor_topic == nullptr) {
+			DEVICE_LOG("failed to create distance_sensor object. Did you start uOrb?");
+		}
+	}
+
+	ret = OK;
+	/* sensor is ok, but we don't really know if it is within range */
+	_sensor_ok = true;
+out:
+	return ret;
+}
+
+int
+TREVO::probe()
+{
+	uint8_t who_am_i = 0;
+
+	const uint8_t cmd = TREVO_WHO_AM_I_REG;
+
+	// set the I2C bus address
+	set_address(TREVO_BASEADDR);
+
+	// can't use a single transfer as TREvo need a bit of time for internal processing
+	if (transfer(&cmd, 1, nullptr, 0) == OK) {
+		if (transfer(nullptr, 0, &who_am_i, 1) == OK && who_am_i == TREVO_WHO_AM_I_REG_VAL) {
+			return measure();
+		}
+	}
+
+	DEVICE_DEBUG("WHO_AM_I byte mismatch 0x%02x should be 0x%02x\n",
+		     (unsigned)who_am_i,
+		     TREVO_WHO_AM_I_REG_VAL);
+
+	// not found on any address
+	return -EIO;
+}
+
+void
+TREVO::set_minimum_distance(float min)
+{
+	_min_distance = min;
+}
+
+void
+TREVO::set_maximum_distance(float max)
+{
+	_max_distance = max;
+}
+
+float
+TREVO::get_minimum_distance()
+{
+	return _min_distance;
+}
+
+float
+TREVO::get_maximum_distance()
+{
+	return _max_distance;
+}
+
+int
+TREVO::ioctl(struct file *filp, int cmd, unsigned long arg)
+{
+	switch (cmd) {
+
+	case SENSORIOCSPOLLRATE: {
+			switch (arg) {
+
+			/* switching to manual polling */
+			case SENSOR_POLLRATE_MANUAL:
+				stop();
+				_measure_ticks = 0;
+				return OK;
+
+			/* external signalling (DRDY) not supported */
+			case SENSOR_POLLRATE_EXTERNAL:
+
+			/* zero would be bad */
+			case 0:
+				return -EINVAL;
+
+			/* set default/max polling rate */
+			case SENSOR_POLLRATE_MAX:
+			case SENSOR_POLLRATE_DEFAULT: {
+					/* do we need to start internal polling? */
+					bool want_start = (_measure_ticks == 0);
+
+					/* set interval for next measurement to minimum legal value */
+					_measure_ticks = USEC2TICK(TREVO_CONVERSION_INTERVAL);
+
+					/* if we need to start the poll state machine, do it */
+					if (want_start) {
+						start();
+					}
+
+					return OK;
+				}
+
+			/* adjust to a legal polling interval in Hz */
+			default: {
+					/* do we need to start internal polling? */
+					bool want_start = (_measure_ticks == 0);
+
+					/* convert hz to tick interval via microseconds */
+					unsigned ticks = USEC2TICK(1000000 / arg);
+
+					/* check against maximum rate */
+					if (ticks < USEC2TICK(TREVO_CONVERSION_INTERVAL)) {
+						return -EINVAL;
+					}
+
+					/* update interval for next measurement */
+					_measure_ticks = ticks;
+
+					/* if we need to start the poll state machine, do it */
+					if (want_start) {
+						start();
+					}
+
+					return OK;
+				}
+			}
+		}
+
+	case SENSORIOCGPOLLRATE:
+		if (_measure_ticks == 0) {
+			return SENSOR_POLLRATE_MANUAL;
+		}
+
+		return (1000 / _measure_ticks);
+
+	case SENSORIOCSQUEUEDEPTH: {
+			/* lower bound is mandatory, upper bound is a sanity check */
+			if ((arg < 1) || (arg > 100)) {
+				return -EINVAL;
+			}
+
+			irqstate_t flags = px4_enter_critical_section();
+
+			if (!_reports->resize(arg)) {
+				px4_leave_critical_section(flags);
+				return -ENOMEM;
+			}
+
+			px4_leave_critical_section(flags);
+
+			return OK;
+		}
+
+	case SENSORIOCGQUEUEDEPTH:
+		return _reports->size();
+
+	case SENSORIOCRESET:
+		/* XXX implement this */
+		return -EINVAL;
+
+	case RANGEFINDERIOCSETMINIUMDISTANCE: {
+			set_minimum_distance(*(float *)arg);
+			return 0;
+		}
+		break;
+
+	case RANGEFINDERIOCSETMAXIUMDISTANCE: {
+			set_maximum_distance(*(float *)arg);
+			return 0;
+		}
+		break;
+
+	default:
+		/* give it to the superclass */
+		return I2C::ioctl(filp, cmd, arg);
+	}
+}
+
+ssize_t
+TREVO::read(struct file *filp, char *buffer, size_t buflen)
+{
+	unsigned count = buflen / sizeof(struct distance_sensor_s);
+	struct distance_sensor_s *rbuf = reinterpret_cast<struct distance_sensor_s *>(buffer);
+	int ret = 0;
+
+	/* buffer must be large enough */
+	if (count < 1) {
+		return -ENOSPC;
+	}
+
+	/* if automatic measurement is enabled */
+	if (_measure_ticks > 0) {
+
+		/*
+		 * While there is space in the caller's buffer, and reports, copy them.
+		 * Note that we may be pre-empted by the workq thread while we are doing this;
+		 * we are careful to avoid racing with them.
+		 */
+		while (count--) {
+			if (_reports->get(rbuf)) {
+				ret += sizeof(*rbuf);
+				rbuf++;
+			}
+		}
+
+		/* if there was no data, warn the caller */
+		return ret ? ret : -EAGAIN;
+	}
+
+	/* manual measurement - run one conversion */
+	do {
+		_reports->flush();
+
+		/* trigger a measurement */
+		if (OK != measure()) {
+			ret = -EIO;
+			break;
+		}
+
+		/* wait for it to complete */
+		usleep(TREVO_CONVERSION_INTERVAL);
+
+		/* run the collection phase */
+		if (OK != collect()) {
+			ret = -EIO;
+			break;
+		}
+
+		/* state machine will have generated a report, copy it out */
+		if (_reports->get(rbuf)) {
+			ret = sizeof(*rbuf);
+		}
+
+	} while (0);
+
+	return ret;
+}
+
+int
+TREVO::measure()
+{
+	int ret;
+
+	/*
+	 * Send the command to begin a measurement.
+	 */
+	const uint8_t cmd = TREVO_MEASURE_REG;
+	ret = transfer(&cmd, sizeof(cmd), nullptr, 0);
+
+	if (OK != ret) {
+		perf_count(_comms_errors);
+		DEVICE_LOG("i2c::transfer returned %d", ret);
+		return ret;
+	}
+
+	ret = OK;
+
+	return ret;
+}
+
+int
+TREVO::collect()
+{
+	int ret = -EIO;
+
+	/* read from the sensor */
+	uint8_t val[3] = {0, 0, 0};
+
+	perf_begin(_sample_perf);
+
+	ret = transfer(nullptr, 0, &val[0], 3);
+
+	if (ret < 0) {
+		DEVICE_LOG("error reading from sensor: %d", ret);
+		perf_count(_comms_errors);
+		perf_end(_sample_perf);
+		return ret;
+	}
+
+	uint16_t distance_mm = (val[0] << 8) | val[1];
+	float distance_m = float(distance_mm) *  1e-3f;
+	struct distance_sensor_s report;
+
+	report.timestamp = hrt_absolute_time();
+	/* there is no enum item for a combined LASER and ULTRASOUND which it should be */
+	report.type = distance_sensor_s::MAV_DISTANCE_SENSOR_LASER;
+	report.orientation = 8;
+	report.current_distance = distance_m;
+	report.min_distance = get_minimum_distance();
+	report.max_distance = get_maximum_distance();
+	report.covariance = 0.0f;
+	/* TODO: set proper ID */
+	report.id = 0;
+
+	// This validation check can be used later
+	_valid = crc8(val, 2) == val[2] && (float)report.current_distance > report.min_distance
+		 && (float)report.current_distance < report.max_distance ? 1 : 0;
+
+	/* publish it, if we are the primary */
+	if (_distance_sensor_topic != nullptr) {
+		orb_publish(ORB_ID(distance_sensor), _distance_sensor_topic, &report);
+	}
+
+	if (_reports->force(&report)) {
+		perf_count(_buffer_overflows);
+	}
+
+	/* notify anyone waiting for data */
+	poll_notify(POLLIN);
+
+	ret = OK;
+
+	perf_end(_sample_perf);
+	return ret;
+}
+
+void
+TREVO::start()
+{
+	/* reset the report ring and state machine */
+	_collect_phase = false;
+	_reports->flush();
+
+	/* schedule a cycle to start things */
+	work_queue(HPWORK, &_work, (worker_t)&TREVO::cycle_trampoline, this, 1);
+
+	/* notify about state change */
+	struct subsystem_info_s info = {};
+	info.present = true;
+	info.enabled = true;
+	info.ok = true;
+	info.subsystem_type = subsystem_info_s::SUBSYSTEM_TYPE_RANGEFINDER;
+
+	static orb_advert_t pub = nullptr;
+
+	if (pub != nullptr) {
+		orb_publish(ORB_ID(subsystem_info), pub, &info);
+
+	} else {
+		pub = orb_advertise(ORB_ID(subsystem_info), &info);
+	}
+}
+
+void
+TREVO::stop()
+{
+	work_cancel(HPWORK, &_work);
+}
+
+void
+TREVO::cycle_trampoline(void *arg)
+{
+	TREVO *dev = (TREVO *)arg;
+
+	dev->cycle();
+}
+
+void
+TREVO::cycle()
+{
+	/* collection phase? */
+	if (_collect_phase) {
+
+		/* perform collection */
+		if (OK != collect()) {
+			DEVICE_LOG("collection error");
+			/* restart the measurement state machine */
+			start();
+			return;
+		}
+
+		/* next phase is measurement */
+		_collect_phase = false;
+
+		/*
+		 * Is there a collect->measure gap?
+		 */
+		if (_measure_ticks > USEC2TICK(TREVO_CONVERSION_INTERVAL)) {
+			/* schedule a fresh cycle call when we are ready to measure again */
+			work_queue(HPWORK,
+				   &_work,
+				   (worker_t)&TREVO::cycle_trampoline,
+				   this,
+				   _measure_ticks - USEC2TICK(TREVO_CONVERSION_INTERVAL));
+
+			return;
+		}
+	}
+
+	/* measurement phase */
+	if (OK != measure()) {
+		DEVICE_LOG("measure error");
+	}
+
+	/* next phase is collection */
+	_collect_phase = true;
+
+	/* schedule a fresh cycle call when the measurement is done */
+	work_queue(HPWORK,
+		   &_work,
+		   (worker_t)&TREVO::cycle_trampoline,
+		   this,
+		   USEC2TICK(TREVO_CONVERSION_INTERVAL));
+}
+
+void
+TREVO::print_info()
+{
+	perf_print_counter(_sample_perf);
+	perf_print_counter(_comms_errors);
+	perf_print_counter(_buffer_overflows);
+	printf("poll interval:  %u ticks\n", _measure_ticks);
+	_reports->print_info("report queue");
+}
+
+/**
+ * Local functions in support of the shell command.
+ */
+namespace trevo
+{
+
+TREVO	*g_dev;
+
+void	start();
+void	stop();
+void	test();
+void	reset();
+void	info();
+
+/**
+ * Start the driver.
+ */
+void
+start()
+{
+	int fd;
+
+	if (g_dev != nullptr) {
+		errx(1, "already started");
+	}
+
+	/* create the driver */
+	g_dev = new TREVO(TREVO_BUS);
+
+
+	if (g_dev == nullptr) {
+		goto fail;
+	}
+
+	if (OK != g_dev->init()) {
+		goto fail;
+	}
+
+	/* set the poll rate to default, starts automatic data collection */
+	fd = open(TREVO_DEVICE_PATH, O_RDONLY);
+
+	if (fd < 0) {
+		goto fail;
+	}
+
+	if (ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT) < 0) {
+		goto fail;
+	}
+
+	exit(0);
+
+fail:
+
+	if (g_dev != nullptr) {
+		delete g_dev;
+		g_dev = nullptr;
+	}
+
+	errx(1, "driver start failed");
+}
+
+/**
+ * Stop the driver
+ */
+void stop()
+{
+	if (g_dev != nullptr) {
+		delete g_dev;
+		g_dev = nullptr;
+
+	} else {
+		errx(1, "driver not running");
+	}
+
+	exit(0);
+}
+
+/**
+ * Perform some basic functional tests on the driver;
+ * make sure we can collect data from the sensor in polled
+ * and automatic modes.
+ */
+void
+test()
+{
+	struct distance_sensor_s report;
+	ssize_t sz;
+	int ret;
+
+	int fd = open(TREVO_DEVICE_PATH, O_RDONLY);
+
+	if (fd < 0) {
+		err(1, "%s open failed (try 'trevo start' if the driver is not running", TREVO_DEVICE_PATH);
+	}
+
+	/* do a simple demand read */
+	sz = read(fd, &report, sizeof(report));
+
+	if (sz != sizeof(report)) {
+		err(1, "immediate read failed");
+	}
+
+	warnx("single read");
+	warnx("measurement: %0.2f m", (double)report.current_distance);
+	warnx("time:        %llu", report.timestamp);
+
+	/* start the sensor polling at 2Hz */
+	if (OK != ioctl(fd, SENSORIOCSPOLLRATE, 2)) {
+		errx(1, "failed to set 2Hz poll rate");
+	}
+
+	/* read the sensor 50x and report each value */
+	for (unsigned i = 0; i < 50; i++) {
+		struct pollfd fds;
+
+		/* wait for data to be ready */
+		fds.fd = fd;
+		fds.events = POLLIN;
+		ret = poll(&fds, 1, 2000);
+
+		if (ret != 1) {
+			errx(1, "timed out waiting for sensor data");
+		}
+
+		/* now go get it */
+		sz = read(fd, &report, sizeof(report));
+
+		if (sz != sizeof(report)) {
+			err(1, "periodic read failed");
+		}
+
+		warnx("periodic read %u", i);
+		warnx("measurement: %0.3f", (double)report.current_distance);
+		warnx("time:        %llu", report.timestamp);
+	}
+
+	/* reset the sensor polling to default rate */
+	if (OK != ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT)) {
+		errx(1, "failed to set default poll rate");
+	}
+
+	errx(0, "PASS");
+}
+
+/**
+ * Reset the driver.
+ */
+void
+reset()
+{
+	int fd = open(TREVO_DEVICE_PATH, O_RDONLY);
+
+	if (fd < 0) {
+		err(1, "failed ");
+	}
+
+	if (ioctl(fd, SENSORIOCRESET, 0) < 0) {
+		err(1, "driver reset failed");
+	}
+
+	if (ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT) < 0) {
+		err(1, "driver poll restart failed");
+	}
+
+	exit(0);
+}
+
+/**
+ * Print a little info about the driver.
+ */
+void
+info()
+{
+	if (g_dev == nullptr) {
+		errx(1, "driver not running");
+	}
+
+	printf("state @ %p\n", g_dev);
+	g_dev->print_info();
+
+	exit(0);
+}
+
+} // namespace
+
+int
+trevo_main(int argc, char *argv[])
+{
+	/*
+	 * Start/load the driver.
+	 */
+	if (!strcmp(argv[1], "start")) {
+		trevo::start();
+	}
+
+	/*
+	 * Stop the driver
+	 */
+	if (!strcmp(argv[1], "stop")) {
+		trevo::stop();
+	}
+
+	/*
+	 * Test the driver/device.
+	 */
+	if (!strcmp(argv[1], "test")) {
+		trevo::test();
+	}
+
+	/*
+	 * Reset the driver.
+	 */
+	if (!strcmp(argv[1], "reset")) {
+		trevo::reset();
+	}
+
+	/*
+	 * Print driver information.
+	 */
+	if (!strcmp(argv[1], "info") || !strcmp(argv[1], "status")) {
+		trevo::info();
+	}
+
+	errx(1, "unrecognized command, try 'start', 'test', 'reset' or 'info'");
+}

src/modules/sensors/sensor_params.c

@@ -1087,6 +1087,16 @@ PARAM_DEFINE_INT32(SENS_EN_SF0X, 0);
  */
 PARAM_DEFINE_INT32(SENS_EN_MB12XX, 0);
 
+/**
+ * TeraRanger Evo (trevo)
+ *
+ * @reboot_required true
+ *
+ * @boolean
+ * @group Sensor Enable
+ */
+ PARAM_DEFINE_INT32(SENS_EN_TREVO, 0);
+
 /**
  * TeraRanger One (trone)
  *