Adding AK09916 driver to support the Here2 GNSS emulated mag (I2C) (#11837)

* drivers, magnetometer: added ak09916 driver to support the mag driver emulated by the Here2 gps
* boards: set yaw 270 rotation for external ak09916 driver and only start it for the PH21
* drivers: only start ak09916 when icm20948 is not available on a ph21 setup

boards/px4/fmu-v3/init/rc.board_sensors

@@ -60,7 +60,11 @@ then
 	param set SENS_EN_THERMAL 0
 
 	# ICM20948 as external magnetometer on I2C (e.g. Here GPS)
-	icm20948 -X -M -R 6 start
+	if ! icm20948 -X -M -R 6 start
+	then
+		# external emulated AK09916 (Here2) is rotated 270 degrees yaw
+		ak09916 -X -R 6 start
+	fi
 
 	# external L3GD20H is rotated 180 degrees yaw
 	l3gd20 -X -R 4 start

src/drivers/magnetometer/CMakeLists.txt

@@ -31,6 +31,7 @@
 #
 ############################################################################
 
+add_subdirectory(ak09916)
 add_subdirectory(bmm150)
 add_subdirectory(hmc5883)
 add_subdirectory(qmc5883)

src/drivers/magnetometer/ak09916/CMakeLists.txt

+############################################################################
+#
+#   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__ak09916
+	MAIN ak09916
+	STACK_MAIN 1200
+	COMPILE_FLAGS
+		-Wno-cast-align # TODO: fix and enable
+	SRCS
+		ak09916.cpp
+	DEPENDS
+	)
+

src/drivers/magnetometer/ak09916/ak09916.cpp

+/****************************************************************************
+ *
+ *   Copyright (c) 2019 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 mag.cpp
+ *
+ * Driver for the ak09916 magnetometer within the Invensense mpu9250
+ *
+ * @author Robert Dickenson
+ *
+ */
+
+#include <px4_config.h>
+#include <px4_log.h>
+#include <px4_time.h>
+#include <lib/perf/perf_counter.h>
+#include <drivers/drv_hrt.h>
+#include <drivers/device/spi.h>
+#include <drivers/device/ringbuffer.h>
+#include <drivers/device/integrator.h>
+#include <drivers/drv_accel.h>
+#include <drivers/drv_gyro.h>
+#include <drivers/drv_mag.h>
+#include <lib/mathlib/math/filter/LowPassFilter2p.hpp>
+#include <lib/conversion/rotation.h>
+
+
+#include <nuttx/arch.h>
+#include <nuttx/wqueue.h>
+#include <nuttx/clock.h>
+
+#include "ak09916.hpp"
+#include <px4_getopt.h>
+
+/** driver 'main' command */
+extern "C" { __EXPORT int ak09916_main(int argc, char *argv[]); }
+
+#define AK09916_CONVERSION_INTERVAL	(1000000 / 100)	/* microseconds */
+
+namespace ak09916
+{
+
+AK09916 *g_dev_ext;
+AK09916 *g_dev_int;
+
+void start(bool, enum Rotation);
+void test(bool);
+void reset(bool);
+void info(bool);
+void usage();
+
+
+/**
+ * Start the driver.
+ *
+ * This function only returns if the driver is up and running
+ * or failed to detect the sensor.
+ */
+void start(bool external_bus, enum Rotation rotation)
+{
+	int fd;
+	AK09916 **g_dev_ptr = (external_bus ? &g_dev_ext : &g_dev_int);
+	const char *path = (external_bus ? AK09916_DEVICE_PATH_MAG_EXT : AK09916_DEVICE_PATH_MAG);
+
+	if (*g_dev_ptr != nullptr)
+		/* if already started, the still command succeeded */
+	{
+		PX4_ERR("already started");
+		exit(0);
+	}
+
+	/* create the driver */
+	if (external_bus) {
+#if defined(PX4_I2C_BUS_EXPANSION)
+		*g_dev_ptr = new AK09916(PX4_I2C_BUS_EXPANSION, path, rotation);
+#else
+		PX4_ERR("External I2C not available");
+		exit(0);
+#endif
+
+	} else {
+		PX4_ERR("Internal I2C not available");
+		exit(0);
+	}
+
+	if (*g_dev_ptr == nullptr) {
+		goto fail;
+	}
+
+
+	if (OK != (*g_dev_ptr)->init()) {
+		goto fail;
+	}
+
+	/* set the poll rate to default, starts automatic data collection */
+	fd = open(path, O_RDONLY);
+
+	if (fd < 0) {
+		goto fail;
+	}
+
+	if (ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT) < 0) {
+		close(fd);
+		PX4_ERR("Failed to setup poll rate");
+	}
+
+	close(fd);
+
+	exit(0);
+fail:
+
+	if (*g_dev_ptr != nullptr) {
+		delete (*g_dev_ptr);
+		*g_dev_ptr = nullptr;
+	}
+
+	PX4_ERR("driver start failed");
+	exit(1);
+
+}
+
+
+void test(bool external_bus)
+{
+	int fd = -1;
+	const char *path = (external_bus ? AK09916_DEVICE_PATH_MAG_EXT : AK09916_DEVICE_PATH_MAG);
+	struct mag_report m_report;
+	ssize_t sz;
+
+
+	/* get the driver */
+	fd = open(path, O_RDONLY);
+
+	if (fd < 0) {
+		PX4_ERR("%s open failed (try 'AK09916 start' if the driver is not running)", path);
+		exit(1);
+	}
+
+	/* do a simple demand read */
+	sz = read(fd, &m_report, sizeof(m_report));
+
+	if (sz != sizeof(m_report)) {
+		PX4_ERR("immediate mag read failed");
+		exit(1);
+	}
+
+	PX4_WARN("single read");
+	PX4_WARN("time:     %lld", m_report.timestamp);
+	PX4_WARN("mag  x:  \t%8.4f\t", (double)m_report.x);
+	PX4_WARN("mag  y:  \t%8.4f\t", (double)m_report.y);
+	PX4_WARN("mag  z:  \t%8.4f\t", (double)m_report.z);
+	PX4_WARN("mag  x:  \t%d\traw 0x%0x", (short)m_report.x_raw, (unsigned short)m_report.x_raw);
+	PX4_WARN("mag  y:  \t%d\traw 0x%0x", (short)m_report.y_raw, (unsigned short)m_report.y_raw);
+	PX4_WARN("mag  z:  \t%d\traw 0x%0x", (short)m_report.z_raw, (unsigned short)m_report.z_raw);
+
+	PX4_ERR("PASS");
+	exit(0);
+
+}
+
+
+void
+reset(bool external_bus)
+{
+	const char *path = external_bus ? AK09916_DEVICE_PATH_MAG_EXT : AK09916_DEVICE_PATH_MAG;
+	int fd = open(path, O_RDONLY);
+
+	if (fd < 0) {
+		PX4_ERR("failed");
+		exit(1);
+	}
+
+	if (ioctl(fd, SENSORIOCRESET, 0) < 0) {
+		PX4_ERR("driver reset failed");
+		exit(1);
+	}
+
+	if (ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT) < 0) {
+		PX4_ERR("driver poll restart failed");
+		exit(1);
+	}
+
+	exit(0);
+
+}
+
+void
+info(bool external_bus)
+{
+	AK09916 **g_dev_ptr = external_bus ? &g_dev_ext : &g_dev_int;
+
+	if (*g_dev_ptr == nullptr) {
+		PX4_ERR("driver not running");
+		exit(1);
+	}
+
+	printf("state @ %p\n", *g_dev_ptr);
+	(*g_dev_ptr)->print_info();
+
+	exit(0);
+
+}
+
+void
+usage()
+{
+	PX4_WARN("missing command: try 'start', 'info', 'test', 'stop',\n'reset'");
+	PX4_WARN("options:");
+	PX4_WARN("    -X    (external bus)");
+
+}
+
+} // namespace AK09916
+
+// If interface is non-null, then it will used for interacting with the device.
+// Otherwise, it will passthrough the parent AK09916
+AK09916::AK09916(int bus, const char *path, enum Rotation rotation) :
+	I2C("AK09916", path, bus, AK09916_I2C_ADDR, 400000),
+	_measure_ticks(0),
+	_rotation(rotation),
+	_mag_topic(nullptr),
+	_mag_orb_class_instance(-1),
+	_mag_class_instance(-1),
+	_mag_reading_data(false),
+	_mag_reports(nullptr),
+	_mag_scale{},
+	_mag_range_scale(),
+	_mag_reads(perf_alloc(PC_COUNT, "ak09916_mag_reads")),
+	_mag_errors(perf_alloc(PC_COUNT, "ak09916_mag_errors")),
+	_mag_overruns(perf_alloc(PC_COUNT, "ak09916_mag_overruns")),
+	_mag_overflows(perf_alloc(PC_COUNT, "ak09916_mag_overflows")),
+	_mag_duplicates(perf_alloc(PC_COUNT, "ak09916_mag_duplicates")),
+	_mag_asa_x(1.0),
+	_mag_asa_y(1.0),
+	_mag_asa_z(1.0),
+	_last_mag_data{}
+{
+	// default mag scale factors
+	_mag_scale.x_offset = 0;
+	_mag_scale.x_scale  = 1.0f;
+	_mag_scale.y_offset = 0;
+	_mag_scale.y_scale  = 1.0f;
+	_mag_scale.z_offset = 0;
+	_mag_scale.z_scale  = 1.0f;
+
+	_mag_range_scale = AK09916_MAG_RANGE_GA;
+
+
+	// work_cancel in the dtor will explode if we don't do this...
+	memset(&_work, 0, sizeof(_work));
+}
+
+AK09916::~AK09916()
+{
+	if (_mag_class_instance != -1) {
+		unregister_class_devname(MAG_BASE_DEVICE_PATH, _mag_class_instance);
+	}
+
+	if (_mag_reports != nullptr) {
+		delete _mag_reports;
+	}
+
+	orb_unadvertise(_mag_topic);
+
+	perf_free(_mag_reads);
+	perf_free(_mag_errors);
+	perf_free(_mag_overruns);
+	perf_free(_mag_overflows);
+	perf_free(_mag_duplicates);
+}
+
+int
+AK09916::init()
+{
+	int ret = I2C::init();
+
+	/* if cdev init failed, bail now */
+	if (ret != OK) {
+		DEVICE_DEBUG("AK09916 mag init failed");
+
+		return ret;
+	}
+
+	_mag_reports = new ringbuffer::RingBuffer(2, sizeof(mag_report));
+
+	if (_mag_reports == nullptr) {
+		return -ENOMEM;
+	}
+
+	_mag_class_instance = register_class_devname(MAG_BASE_DEVICE_PATH);
+
+	reset();
+
+	/* advertise sensor topic, measure manually to initialize valid report */
+	struct mag_report mrp;
+	_mag_reports->get(&mrp);
+
+	_mag_topic = orb_advertise_multi(ORB_ID(sensor_mag), &mrp,
+					 &_mag_orb_class_instance, ORB_PRIO_VERY_HIGH);
+//    &_mag_orb_class_instance, ORB_PRIO_LOW);
+
+	if (_mag_topic == nullptr) {
+		PX4_ERR("ADVERT FAIL");
+		return -ENOMEM;
+	}
+
+	return OK;
+}
+
+bool AK09916::check_duplicate(uint8_t *mag_data)
+{
+	if (memcmp(mag_data, &_last_mag_data, sizeof(_last_mag_data)) == 0) {
+		// it isn't new data - wait for next timer
+		return true;
+
+	} else {
+		memcpy(&_last_mag_data, mag_data, sizeof(_last_mag_data));
+		return false;
+	}
+}
+
+void
+AK09916::measure()
+{
+	uint8_t ret, cmd = AK09916REG_ST1;
+	struct ak09916_regs raw_data;
+
+	ret = transfer(&cmd, 1, (uint8_t *)(&raw_data), sizeof(struct ak09916_regs));
+
+	if (ret == OK) {
+		raw_data.st2 = raw_data.st2;
+
+		_measure(raw_data);
+	}
+}
+
+void
+AK09916::_measure(struct ak09916_regs data)
+{
+	bool mag_notify = true;
+
+	if (check_duplicate((uint8_t *)&data.x) && !(data.st1 & 0x02)) {
+		perf_count(_mag_duplicates);
+		return;
+	}
+
+	/* monitor for if data overrun flag is ever set */
+	if (data.st1 & 0x02) {
+		perf_count(_mag_overruns);
+	}
+
+	/* monitor for if magnetic sensor overflow flag is ever set noting that st2
+	 * is usually not even refreshed, but will always be in the same place in the
+	 * mpu's buffers regardless, hence the actual count would be bogus
+	 */
+	if (data.st2 & 0x08) {
+		perf_count(_mag_overflows);
+	}
+
+	mag_report	mrb;
+	mrb.timestamp = hrt_absolute_time();
+	mrb.is_external = true;
+
+	float xraw_f, yraw_f, zraw_f;
+	mrb.x_raw = data.x;
+	mrb.y_raw = data.y;
+	mrb.z_raw = data.z;
+
+	xraw_f = data.x;
+	yraw_f = data.y;
+	zraw_f = data.z;
+	/* apply user specified rotation */
+	rotate_3f(_rotation, xraw_f, yraw_f, zraw_f);
+
+
+	mrb.x = ((xraw_f * _mag_range_scale * _mag_asa_x) - _mag_scale.x_offset) * _mag_scale.x_scale;
+	mrb.y = ((yraw_f * _mag_range_scale * _mag_asa_y) - _mag_scale.y_offset) * _mag_scale.y_scale;
+	mrb.z = ((zraw_f * _mag_range_scale * _mag_asa_z) - _mag_scale.z_offset) * _mag_scale.z_scale;
+	_last_report.x = mrb.x;
+	_last_report.y = mrb.y;
+	_last_report.z = mrb.z;
+	mrb.scaling = _mag_range_scale;
+	mrb.device_id = _device_id.devid;
+
+	mrb.error_count = perf_event_count(_mag_errors);
+
+	_mag_reports->force(&mrb);
+
+	/* notify anyone waiting for data */
+	if (mag_notify) {
+		poll_notify(POLLIN);
+	}
+
+	if (mag_notify && !(_pub_blocked)) {
+		/* publish it */
+		orb_publish(ORB_ID(sensor_mag), _mag_topic, &mrb);
+	}
+}
+
+ssize_t
+AK09916::read(struct file *filp, char *buffer, size_t buflen)
+{
+	unsigned count = buflen / sizeof(mag_report);
+	struct mag_report *mag_buf = reinterpret_cast<struct mag_report *>(buffer);
+	int ret = 0;
+
+	/* buffer must be large enough */
+	if (count < 1) {
+		return -ENOSPC;
+	}
+
+	/* manual measurement - run one conversion */
+	/* XXX really it'd be nice to lock against other readers here */
+	do {
+		_mag_reports->flush();
+
+		/* trigger a measurement */
+		measure();
+
+		if (_mag_reports->get(mag_buf)) {
+			ret = sizeof(struct mag_report);
+		}
+	} while (0);
+
+	/* return the number of bytes transferred */
+	return ret;
+
+}
+
+
+void
+AK09916::print_info()
+{
+	perf_print_counter(_mag_reads);
+	perf_print_counter(_mag_errors);
+	perf_print_counter(_mag_overruns);
+	_mag_reports->print_info("mag queue");
+
+	printf("output  (%.2f %.2f %.2f)\n", (double)_last_report.x, (double)_last_report.y, (double)_last_report.z);
+	printf("\n");
+
+}
+
+
+int
+AK09916::ioctl(struct file *filp, int cmd, unsigned long arg)
+{
+	/*
+	 * Repeated in ICM20948_accel::ioctl
+	 * Both accel and mag CDev could be unused in case of magnetometer only mode or MPU6500
+	 */
+
+	switch (cmd) {
+	case SENSORIOCSPOLLRATE: {
+			switch (arg) {
+
+			/* zero would be bad */
+			case 0:
+				return -EINVAL;
+
+			/* set default polling rate */
+			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(AK09916_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(AK09916_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 SENSORIOCRESET:
+		return reset();
+
+	case MAGIOCSSCALE:
+		/* copy scale in */
+		memcpy(&_mag_scale, (struct mag_scale *) arg, sizeof(_mag_scale));
+		return OK;
+
+	case MAGIOCGSCALE:
+		/* copy scale out */
+		memcpy((struct mag_scale *) arg, &_mag_scale, sizeof(_mag_scale));
+		return OK;
+
+	case MAGIOCCALIBRATE:
+		return OK;
+
+	case MAGIOCEXSTRAP:
+		return OK;
+
+	default:
+		return (int)I2C::ioctl(filp, cmd, arg);
+	}
+}
+
+uint8_t
+AK09916::read_reg(uint8_t reg)
+{
+	const uint8_t cmd = reg;
+	uint8_t ret;
+
+	transfer(&cmd, 1, &ret, 1);
+
+	return ret;
+}
+
+bool
+AK09916::check_id(uint8_t &deviceid)
+{
+	deviceid = read_reg(AK09916REG_WIA);
+
+	return (AK09916_DEVICE_ID_A == deviceid);
+}
+
+void
+AK09916::write_reg(uint8_t reg, uint8_t value)
+{
+	const uint8_t cmd[2] = { reg, value};
+	transfer(cmd, 2, nullptr, 0);
+}
+
+int
+AK09916::reset(void)
+{
+	// First initialize it to use the bus
+	int rv = setup();
+
+	if (rv == OK) {
+		// Now reset the mag
+		write_reg(AK09916REG_CNTL3, AK09916_RESET);
+
+		// Then re-initialize the bus/mag
+		rv = setup();
+	}
+
+	return rv;
+}
+
+int
+AK09916::setup(void)
+{
+	int retries = 10;
+
+	do {
+		write_reg(AK09916REG_CNTL3, AK09916_RESET);
+
+		uint8_t id = 0;
+
+		if (check_id(id)) {
+			break;
+		}
+
+		retries--;
+	} while (retries > 0);
+
+	write_reg(AK09916REG_CNTL2, AK09916_CNTL2_CONTINOUS_MODE_100HZ);
+
+	return OK;
+}
+
+
+void
+AK09916::cycle_trampoline(void *arg)
+{
+	AK09916 *dev = (AK09916 *)arg;
+
+	dev->cycle();
+}
+
+
+void
+AK09916::start()
+{
+	/* reset the report ring and state machine */
+	_mag_reports->flush();
+
+	/* schedule a cycle to start things */
+	work_queue(HPWORK, &_work, (worker_t)&AK09916::cycle_trampoline, this, 1);
+}
+
+void
+AK09916::stop()
+{
+	if (_measure_ticks > 0) {
+		/* ensure no new items are queued while we cancel this one */
+		_measure_ticks = 0;
+		work_cancel(HPWORK, &_work);
+	}
+}
+
+void
+AK09916::cycle()
+{
+	if (_measure_ticks == 0) {
+		return;
+	}
+
+	/* measurement phase */
+	measure();
+
+	if (_measure_ticks > 0) {
+		/* schedule a fresh cycle call when the measurement is done */
+		work_queue(HPWORK,
+			   &_work,
+			   (worker_t)&AK09916::cycle_trampoline,
+			   this,
+			   USEC2TICK(AK09916_CONVERSION_INTERVAL));
+	}
+}
+
+int
+ak09916_main(int argc, char *argv[])
+{
+	int myoptind = 1;
+	int ch;
+	const char *myoptarg = nullptr;
+	bool external_bus = false;
+	enum Rotation rotation = ROTATION_NONE;
+
+	while ((ch = px4_getopt(argc, argv, "XR:", &myoptind, &myoptarg)) != EOF) {
+		switch (ch) {
+		case 'X':
+			external_bus = true;
+			break;
+
+		case 'R':
+			rotation = (enum Rotation)atoi(myoptarg);
+			break;
+
+		default:
+			ak09916::usage();
+			return 0;
+		}
+	}
+
+	if (myoptind >= argc) {
+		ak09916::usage();
+		return -1;
+	}
+
+	const char *verb = argv[myoptind];
+
+	/*
+	 * Start/load the driver.
+	 */
+	if (!strcmp(verb, "start")) {
+		ak09916::start(external_bus, rotation);
+	}
+
+
+	/*
+	 * Test the driver/device.
+	 */
+	if (!strcmp(verb, "test")) {
+		ak09916::test(external_bus);
+	}
+
+	/*
+	 * Reset the driver.
+	 */
+	if (!strcmp(verb, "reset")) {
+		ak09916::reset(external_bus);
+	}
+
+	/*
+	 * Print driver information.
+	 */
+	if (!strcmp(verb, "info")) {
+		ak09916::info(external_bus);
+	}
+
+	ak09916::usage();
+	return -1;
+}
\ No newline at end of file

src/drivers/magnetometer/ak09916/ak09916.hpp

+/****************************************************************************
+ *
+ *   Copyright (c) 2019 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.
+ *
+ ****************************************************************************/
+
+#pragma once
+
+
+#include <px4_config.h>
+
+#include <sys/types.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdlib.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 <px4_log.h>
+
+#include <perf/perf_counter.h>
+#include <systemlib/err.h>
+#include <nuttx/wqueue.h>
+#include <systemlib/conversions.h>
+
+#include <nuttx/arch.h>
+#include <nuttx/clock.h>
+
+#include <board_config.h>
+#include <drivers/drv_hrt.h>
+
+#include <drivers/device/ringbuffer.h>
+#include <drivers/device/integrator.h>
+#include <drivers/device/i2c.h>
+#include <drivers/drv_mag.h>
+
+
+#define AK09916_SAMPLE_RATE					100
+#define AK09916_DEVICE_PATH_MAG              "/dev/ak09916_i2c_int"
+
+#define AK09916_DEVICE_PATH_MAG_EXT          "/dev/ak09916_i2c_ext"
+
+/* in 16-bit sampling mode the mag resolution is 1.5 milli Gauss per bit */
+
+#define AK09916_MAG_RANGE_GA        1.5e-3f;
+
+/* ak09916 deviating register addresses and bit definitions */
+#define AK09916_I2C_ADDR         0x0C
+
+#define AK09916_DEVICE_ID_A		0x48
+#define AK09916_DEVICE_ID_B		0x09	// additional ID byte ("INFO" on AK9063 without content specification.)
+
+#define AK09916REG_WIA           0x00
+
+#define AK09916REG_HXL        0x11
+#define AK09916REG_HXH        0x12
+#define AK09916REG_HYL        0x13
+#define AK09916REG_HYH        0x14
+#define AK09916REG_HZL        0x15
+#define AK09916REG_HZH        0x16
+#define AK09916REG_ST1        0x10
+#define AK09916REG_ST2        0x18
+#define AK09916REG_CNTL2          0x31
+#define AK09916REG_CNTL3          0x32
+
+
+#define AK09916_CNTL2_POWERDOWN_MODE            0x00
+#define AK09916_RESET							0x01
+#define AK09916_CNTL2_SINGLE_MODE               0x01 /* default */
+#define AK09916_CNTL2_CONTINOUS_MODE_10HZ       0x02
+#define AK09916_CNTL2_CONTINOUS_MODE_20HZ       0x04
+#define AK09916_CNTL2_CONTINOUS_MODE_50HZ       0x06
+#define AK09916_CNTL2_CONTINOUS_MODE_100HZ      0x08
+#define AK09916_CNTL2_SELFTEST_MODE             0x10
+#define AK09916_CNTL3_SRST                      0x01
+#define AK09916_ST1_DRDY                        0x01
+#define AK09916_ST1_DOR                         0x02
+
+
+#pragma pack(push, 1)
+struct ak09916_regs {
+	uint8_t st1;
+	int16_t x;
+	int16_t y;
+	int16_t z;
+	uint8_t tmps;
+	uint8_t st2;
+};
+#pragma pack(pop)
+
+
+
+/**
+ * Helper class implementing the magnetometer driver node.
+ */
+class AK09916 : public device::I2C
+{
+public:
+	AK09916(int bus, const char *path, enum Rotation rotation);
+	~AK09916();
+
+	virtual int ioctl(struct file *filp, int cmd, unsigned long arg);
+	virtual int init();
+	virtual ssize_t       read(struct file *filp, char *buffer, size_t buflen);
+
+	void read_block(uint8_t reg, uint8_t *val, uint8_t count);
+
+	int reset(void);
+	int setup(void);
+	void print_info(void);
+	int setup_master_i2c(void);
+	bool check_id(uint8_t &id);
+
+
+	static void cycle_trampoline(void *arg);
+	void start(void);
+	void stop(void);
+	void cycle(void);
+
+protected:
+
+	friend class ICM20948;
+
+	/* Directly measure from the _interface if possible */
+	void measure();
+
+	/* Update the state with prefetched data (internally called by the regular measure() )*/
+	void _measure(struct ak09916_regs data);
+
+	uint8_t read_reg(uint8_t reg);
+	void write_reg(uint8_t reg, uint8_t value);
+
+private:
+	work_s			_work{};
+	unsigned		_measure_ticks;
+
+	enum Rotation _rotation;
+	orb_advert_t _mag_topic;
+	int _mag_orb_class_instance;
+	int _mag_class_instance;
+	bool _mag_reading_data;
+	ringbuffer::RingBuffer *_mag_reports;
+	mag_report   _last_report {};          /**< used for info() */
+	struct mag_calibration_s _mag_scale;
+	float _mag_range_scale;
+	perf_counter_t _mag_reads;
+	perf_counter_t _mag_errors;
+	perf_counter_t _mag_overruns;
+	perf_counter_t _mag_overflows;
+	perf_counter_t _mag_duplicates;
+	float _mag_asa_x;
+	float _mag_asa_y;
+	float _mag_asa_z;
+
+	bool check_duplicate(uint8_t *mag_data);
+
+	// keep last mag reading for duplicate detection
+	uint8_t			_last_mag_data[6];
+
+	/* do not allow to copy this class due to pointer data members */
+	AK09916(const AK09916 &);
+	AK09916 operator=(const AK09916 &);
+};