ICM20948 integration into MPU9250 driver (#10116)

* Integrated preliminary ICM20948 support into MPU9250 driver.
Fixed temperature conversion for MPU9250/ICM20948.
* Included missing check for PX4_I2C_OBDEV_MPU9250 in main.cpp.
* Added explicit bus for internal MPU9250 on Pixhawk 2.1 to avoid implicit start
of an externally attached device with wrong orientation.

ROMFS/px4fmu_common/init.d/rc.sensors

@@ -100,6 +100,9 @@ then
 	teraranger start -a
 fi
 
+# ICM20948 as external magnetometer on I2C (e.g. Here GPS)
+mpu9250 -X -M -R 6 start
+
 ###############################################################################
 #                            End Optional drivers                             #
 ###############################################################################

src/drivers/imu/mpu9250/CMakeLists.txt

@@ -40,6 +40,7 @@ px4_add_module(
 		mpu9250_i2c.cpp
 		mpu9250_spi.cpp
 		main.cpp
+		accel.cpp
 		gyro.cpp
 		mag.cpp
 		mag_i2c.cpp

src/drivers/imu/mpu9250/accel.cpp

@@ -0,0 +1,147 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2012-2016 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 gyro.cpp
+ *
+ * Driver for the Invensense mpu9250 connected via SPI.
+ *
+ * @author Andrew Tridgell
+ *
+ * based on the mpu6000 driver
+ */
+
+#include <px4_config.h>
+#include <ecl/geo/geo.h>
+
+#include <sys/types.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdio.h>
+
+#include <perf/perf_counter.h>
+
+#include <board_config.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 <mathlib/math/filter/LowPassFilter2p.hpp>
+#include <lib/conversion/rotation.h>
+
+#include "mag.h"
+#include "gyro.h"
+#include "mpu9250.h"
+
+MPU9250_accel::MPU9250_accel(MPU9250 *parent, const char *path) :
+	CDev("MPU9250_accel", path),
+	_parent(parent)
+{
+}
+
+MPU9250_accel::~MPU9250_accel()
+{
+	if (_accel_class_instance != -1) {
+		unregister_class_devname(ACCEL_BASE_DEVICE_PATH, _accel_class_instance);
+	}
+}
+
+int
+MPU9250_accel::init()
+{
+	// do base class init
+	int ret = CDev::init();
+
+	/* if probe/setup failed, bail now */
+	if (ret != OK) {
+		DEVICE_DEBUG("accel init failed");
+		return ret;
+	}
+
+	_accel_class_instance = register_class_devname(ACCEL_BASE_DEVICE_PATH);
+
+	return ret;
+}
+
+void
+MPU9250_accel::parent_poll_notify()
+{
+	poll_notify(POLLIN);
+}
+
+int
+MPU9250_accel::ioctl(struct file *filp, int cmd, unsigned long arg)
+{
+	/*
+	 * Repeated in MPU9250_mag::ioctl
+	 * Both accel and mag CDev could be unused in case of magnetometer only mode or MPU6500
+	 */
+
+	switch (cmd) {
+	case SENSORIOCRESET: {
+			return _parent->reset();
+		}
+
+	case SENSORIOCSPOLLRATE: {
+			switch (arg) {
+
+			/* zero would be bad */
+			case 0:
+				return -EINVAL;
+
+			case SENSOR_POLLRATE_DEFAULT:
+				return ioctl(filp, SENSORIOCSPOLLRATE, MPU9250_ACCEL_DEFAULT_RATE);
+
+			/* adjust to a legal polling interval in Hz */
+			default:
+				return _parent->_set_pollrate(arg);
+			}
+		}
+
+	case ACCELIOCSSCALE: {
+			struct accel_calibration_s *s = (struct accel_calibration_s *) arg;
+			memcpy(&_parent->_accel_scale, s, sizeof(_parent->_accel_scale));
+			return OK;
+		}
+
+	default:
+		return CDev::ioctl(filp, cmd, arg);
+	}
+}

src/drivers/imu/mpu9250/accel.h

@@ -0,0 +1,63 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2012-2016 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
+
+class MPU9250;
+
+/**
+ * Helper class implementing the accel driver node.
+ */
+class MPU9250_accel : public device::CDev
+{
+public:
+	MPU9250_accel(MPU9250 *parent, const char *path);
+	~MPU9250_accel();
+
+	virtual int		ioctl(struct file *filp, int cmd, unsigned long arg);
+
+	virtual int		init();
+
+protected:
+	friend class MPU9250;
+
+	void			parent_poll_notify();
+
+private:
+	MPU9250			*_parent;
+
+	orb_advert_t		_accel_topic{nullptr};
+	int			_accel_orb_class_instance{-1};
+	int			_accel_class_instance{-1};
+
+};

src/drivers/imu/mpu9250/gyro.cpp

@@ -42,27 +42,14 @@
  */
 
 #include <px4_config.h>
-
+#include <lib/perf/perf_counter.h>
-#include <sys/types.h>
-#include <stdint.h>
-#include <stdbool.h>
-#include <stddef.h>
-#include <stdlib.h>
-#include <errno.h>
-#include <stdio.h>
-
-#include <perf/perf_counter.h>
-
-#include <board_config.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 <mathlib/math/filter/LowPassFilter2p.hpp>
+#include <lib/mathlib/math/filter/LowPassFilter2p.hpp>
 #include <lib/conversion/rotation.h>
 
 #include "mag.h"
@@ -71,10 +58,7 @@
 
 MPU9250_gyro::MPU9250_gyro(MPU9250 *parent, const char *path) :
 	CDev("MPU9250_gyro", path),
-	_parent(parent),
+	_parent(parent)
-	_gyro_topic(nullptr),
-	_gyro_orb_class_instance(-1),
-	_gyro_class_instance(-1)
 {
 }
 
@@ -88,10 +72,8 @@ MPU9250_gyro::~MPU9250_gyro()
 int
 MPU9250_gyro::init()
 {
-	int ret;
-
 	// do base class init
-	ret = CDev::init();
+	int ret = CDev::init();
 
 	/* if probe/setup failed, bail now */
 	if (ret != OK) {
@@ -110,22 +92,22 @@ MPU9250_gyro::parent_poll_notify()
 	poll_notify(POLLIN);
 }
 
-ssize_t
-MPU9250_gyro::read(struct file *filp, char *buffer, size_t buflen)
-{
-	return _parent->gyro_read(filp, buffer, buflen);
-}
-
 int
 MPU9250_gyro::ioctl(struct file *filp, int cmd, unsigned long arg)
 {
-
 	switch (cmd) {
-	case DEVIOCGDEVICEID:
+
-		return (int)CDev::ioctl(filp, cmd, arg);
+	/* these are shared with the accel side */
-		break;
+	case SENSORIOCSPOLLRATE:
+	case SENSORIOCRESET:
+		return _parent->_accel->ioctl(filp, cmd, arg);
+
+	case GYROIOCSSCALE:
+		/* copy scale in */
+		memcpy(&_parent->_gyro_scale, (struct gyro_calibration_s *) arg, sizeof(_parent->_gyro_scale));
+		return OK;
 
 	default:
-		return _parent->gyro_ioctl(filp, cmd, arg);
+		return CDev::ioctl(filp, cmd, arg);
 	}
 }

src/drivers/imu/mpu9250/gyro.h

@@ -44,7 +44,6 @@ public:
 	MPU9250_gyro(MPU9250 *parent, const char *path);
 	~MPU9250_gyro();
 
-	virtual ssize_t		read(struct file *filp, char *buffer, size_t buflen);
 	virtual int		ioctl(struct file *filp, int cmd, unsigned long arg);
 
 	virtual int		init();
@@ -56,11 +55,8 @@ protected:
 
 private:
 	MPU9250			*_parent;
-	orb_advert_t		_gyro_topic;
-	int			_gyro_orb_class_instance;
-	int			_gyro_class_instance;
 
-	/* do not allow to copy this class due to pointer data members */
+	orb_advert_t		_gyro_topic{nullptr};
-	MPU9250_gyro(const MPU9250_gyro &);
+	int			_gyro_orb_class_instance{-1};
-	MPU9250_gyro operator=(const MPU9250_gyro &);
+	int			_gyro_class_instance{-1};
 };

src/drivers/imu/mpu9250/mag.cpp

@@ -42,27 +42,15 @@
 
 #include <px4_config.h>
 #include <px4_log.h>
-
+#include <lib/perf/perf_counter.h>
-#include <sys/types.h>
-#include <stdint.h>
-#include <stdbool.h>
-#include <stddef.h>
-#include <stdlib.h>
-#include <errno.h>
-#include <stdio.h>
-
-#include <perf/perf_counter.h>
-
-#include <board_config.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 <mathlib/math/filter/LowPassFilter2p.hpp>
+#include <lib/mathlib/math/filter/LowPassFilter2p.hpp>
 #include <lib/conversion/rotation.h>
 
 #include "mag.h"
@@ -129,14 +117,17 @@ MPU9250_mag::init()
 
 	/* if cdev init failed, bail now */
 	if (ret != OK) {
-		DEVICE_DEBUG("MPU9250 mag init failed");
+		if (_parent->_device_type == MPU_DEVICE_TYPE_MPU9250) { DEVICE_DEBUG("MPU9250 mag init failed"); }
+
+		else { DEVICE_DEBUG("ICM20948 mag init failed"); }
+
 		return ret;
 	}
 
 	_mag_reports = new ringbuffer::RingBuffer(2, sizeof(mag_report));
 
 	if (_mag_reports == nullptr) {
-		return -ENOMEM;;
+		return -ENOMEM;
 	}
 
 	_mag_class_instance = register_class_devname(MAG_BASE_DEVICE_PATH);
@@ -147,8 +138,8 @@ MPU9250_mag::init()
 	_mag_reports->get(&mrp);
 
 	_mag_topic = orb_advertise_multi(ORB_ID(sensor_mag), &mrp,
-					 &_mag_orb_class_instance, ORB_PRIO_LOW);
+					 &_mag_orb_class_instance, (_parent->is_external()) ? ORB_PRIO_VERY_HIGH : ORB_PRIO_DEFAULT);
-	//			   &_mag_orb_class_instance, (is_external()) ? ORB_PRIO_MAX - 1 : ORB_PRIO_HIGH - 1);
+//    &_mag_orb_class_instance, ORB_PRIO_LOW);
 
 	if (_mag_topic == nullptr) {
 		PX4_ERR("ADVERT FAIL");
@@ -173,10 +164,23 @@ bool MPU9250_mag::check_duplicate(uint8_t *mag_data)
 void
 MPU9250_mag::measure()
 {
-	struct ak8963_regs data;
+	uint8_t ret;
+	union raw_data_t {
+		struct ak8963_regs ak8963_data;
+		struct ak09916_regs ak09916_data;
+	} raw_data;
 
-	if (OK == _interface->read(AK8963REG_ST1, &data, sizeof(struct ak8963_regs))) {
+	if (_parent->_device_type == MPU_DEVICE_TYPE_MPU9250) {
-		_measure(data);
+		ret = _interface->read(AK8963REG_ST1, &raw_data, sizeof(struct ak8963_regs));
+
+	} else { // ICM20948 --> AK09916
+		ret = _interface->read(AK09916REG_ST1, &raw_data, sizeof(struct ak09916_regs));
+	}
+
+	if (ret == OK) {
+		if (_parent->_device_type == MPU_DEVICE_TYPE_ICM20948) { raw_data.ak8963_data.st2 = raw_data.ak09916_data.st2; }
+
+		_measure(raw_data.ak8963_data);
 	}
 }
 
@@ -205,23 +209,53 @@ MPU9250_mag::_measure(struct ak8963_regs data)
 
 	mag_report	mrb;
 	mrb.timestamp = hrt_absolute_time();
-	mrb.is_external = false;
+//	mrb.is_external = false;
+
+	// need a better check here. Using _parent->is_external() for mpu9250 also sets the
+	// internal magnetometers connected to the "external" spi bus as external, at least
+	// on Pixhawk 2.1. For now assuming the ICM20948 is only used on Here GPS, hence external.
+	if (_parent->_device_type == MPU_DEVICE_TYPE_ICM20948) {
+		mrb.is_external = _parent->is_external();
+
+	} else {
+		mrb.is_external = false;
+	}
 
 	/*
 	 * Align axes - note the accel & gryo are also re-aligned so this
 	 *              doesn't look obvious with the datasheet
 	 */
-	mrb.x_raw =  data.x;
+	float xraw_f, yraw_f, zraw_f;
-	mrb.y_raw = -data.y;
-	mrb.z_raw = -data.z;
 
-	float xraw_f =  data.x;
+	if (_parent->_device_type == MPU_DEVICE_TYPE_ICM20948) {
-	float yraw_f = -data.y;
+		/*
-	float zraw_f = -data.z;
+		 * Keeping consistent with the accel and gyro axes of the ICM20948 here, just aligning the magnetometer to them.
+		 */
+		mrb.x_raw = data.y;
+		mrb.y_raw = data.x;
+		mrb.z_raw = -data.z;
+
+		xraw_f = data.y;
+		yraw_f = data.x;
+		zraw_f = -data.z;
+
+	} else {
+		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(_parent->_rotation, xraw_f, yraw_f, zraw_f);
 
+	if (_parent->_device_type == MPU_DEVICE_TYPE_ICM20948) {
+		rotate_3f(ROTATION_YAW_270, xraw_f, yraw_f, zraw_f); //offset between accel/gyro and mag on icm20948
+	}
+
 	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;
@@ -244,52 +278,14 @@ MPU9250_mag::_measure(struct ak8963_regs data)
 	}
 }
 
-ssize_t
-MPU9250_mag::read(struct file *filp, char *buffer, size_t buflen)
-{
-	unsigned count = buflen / sizeof(mag_report);
-
-	/* buffer must be large enough */
-	if (count < 1) {
-		return -ENOSPC;
-	}
-
-	/* if automatic measurement is not enabled, get a fresh measurement into the buffer */
-	if (_parent->_call_interval == 0) {
-		_mag_reports->flush();
-		/* TODO: this won't work as getting valid magnetometer
-		 *       data requires more than one measure cycle
-		 */
-		_parent->measure();
-	}
-
-	/* if no data, error (we could block here) */
-	if (_mag_reports->empty()) {
-		return -EAGAIN;
-	}
-
-	perf_count(_mag_reads);
-
-	/* copy reports out of our buffer to the caller */
-	mag_report *mrp = reinterpret_cast<mag_report *>(buffer);
-	int transferred = 0;
-
-	while (count--) {
-		if (!_mag_reports->get(mrp)) {
-			break;
-		}
-
-		transferred++;
-		mrp++;
-	}
-
-	/* return the number of bytes transferred */
-	return (transferred * sizeof(mag_report));
-}
-
 int
 MPU9250_mag::ioctl(struct file *filp, int cmd, unsigned long arg)
 {
+	/*
+	 * Repeated in MPU9250_accel::ioctl
+	 * Both accel and mag CDev could be unused in case of magnetometer only mode or MPU6500
+	 */
+
 	switch (cmd) {
 
 	case SENSORIOCRESET:
@@ -302,18 +298,12 @@ MPU9250_mag::ioctl(struct file *filp, int cmd, unsigned long arg)
 			case 0:
 				return -EINVAL;
 
-			/* set default polling rate */
 			case SENSOR_POLLRATE_DEFAULT:
-				return ioctl(filp, SENSORIOCSPOLLRATE, MPU9250_AK8963_SAMPLE_RATE);
+				return ioctl(filp, SENSORIOCSPOLLRATE, MPU9250_ACCEL_DEFAULT_RATE);
 
 			/* adjust to a legal polling interval in Hz */
-			default: {
+			default:
-					if (MPU9250_AK8963_SAMPLE_RATE != arg) {
+				return _parent->_set_pollrate(arg);
-						return -EINVAL;
-					}
-
-					return OK;
-				}
 			}
 		}
 
@@ -337,19 +327,20 @@ MPU9250_mag::set_passthrough(uint8_t reg, uint8_t size, uint8_t *out)
 {
 	uint8_t addr;
 
-	_parent->write_reg(MPUREG_I2C_SLV0_CTRL, 0); // ensure slave r/w is disabled before changing the registers
+	_parent->write_reg(AK_MPU_OR_ICM(MPUREG_I2C_SLV0_CTRL, ICMREG_20948_I2C_SLV0_CTRL),
+			   0); // ensure slave r/w is disabled before changing the registers
 
 	if (out) {
-		_parent->write_reg(MPUREG_I2C_SLV0_D0, *out);
+		_parent->write_reg(AK_MPU_OR_ICM(MPUREG_I2C_SLV0_D0, ICMREG_20948_I2C_SLV0_DO), *out);
 		addr = AK8963_I2C_ADDR;
 
 	} else {
 		addr = AK8963_I2C_ADDR | BIT_I2C_READ_FLAG;
 	}
 
-	_parent->write_reg(MPUREG_I2C_SLV0_ADDR, addr);
+	_parent->write_reg(AK_MPU_OR_ICM(MPUREG_I2C_SLV0_ADDR, ICMREG_20948_I2C_SLV0_ADDR), addr);
-	_parent->write_reg(MPUREG_I2C_SLV0_REG,  reg);
+	_parent->write_reg(AK_MPU_OR_ICM(MPUREG_I2C_SLV0_REG, ICMREG_20948_I2C_SLV0_REG),  reg);
-	_parent->write_reg(MPUREG_I2C_SLV0_CTRL, size | BIT_I2C_SLV0_EN);
+	_parent->write_reg(AK_MPU_OR_ICM(MPUREG_I2C_SLV0_CTRL, ICMREG_20948_I2C_SLV0_CTRL), size | BIT_I2C_SLV0_EN);
 }
 
 void
@@ -363,8 +354,8 @@ MPU9250_mag::passthrough_read(uint8_t reg, uint8_t *buf, uint8_t size)
 {
 	set_passthrough(reg, size);
 	usleep(25 + 25 * size); // wait for the value to be read from slave
-	read_block(MPUREG_EXT_SENS_DATA_00, buf, size);
+	read_block(AK_MPU_OR_ICM(MPUREG_EXT_SENS_DATA_00, ICMREG_20948_EXT_SLV_SENS_DATA_00), buf, size);
-	_parent->write_reg(MPUREG_I2C_SLV0_CTRL, 0); // disable new reads
+	_parent->write_reg(AK_MPU_OR_ICM(MPUREG_I2C_SLV0_CTRL, ICMREG_20948_I2C_SLV0_CTRL), 0); // disable new reads
 }
 
 uint8_t
@@ -382,7 +373,6 @@ MPU9250_mag::read_reg(unsigned int reg)
 	return buf;
 }
 
-
 bool
 MPU9250_mag::ak8963_check_id(uint8_t &deviceid)
 {
@@ -399,11 +389,9 @@ MPU9250_mag::passthrough_write(uint8_t reg, uint8_t val)
 {
 	set_passthrough(reg, 1, &val);
 	usleep(50); // wait for the value to be written to slave
-	_parent->write_reg(MPUREG_I2C_SLV0_CTRL, 0); // disable new writes
+	_parent->write_reg(AK_MPU_OR_ICM(MPUREG_I2C_SLV0_CTRL, ICMREG_20948_I2C_SLV0_CTRL), 0); // disable new writes
 }
 
-
-
 void
 MPU9250_mag::write_reg(unsigned reg, uint8_t value)
 {
@@ -416,26 +404,21 @@ MPU9250_mag::write_reg(unsigned reg, uint8_t value)
 	}
 }
 
-
-
-
 int
 MPU9250_mag::ak8963_reset(void)
 {
 	// First initialize it to use the bus
-
 	int rv = ak8963_setup();
 
 	if (rv == OK) {
 
 		// Now reset the mag
-		write_reg(AK8963REG_CNTL2, AK8963_RESET);
+		write_reg(AK_MPU_OR_ICM(AK8963REG_CNTL2, AK09916REG_CNTL3), AK8963_RESET);
 		// Then re-initialize the bus/mag
 		rv = ak8963_setup();
 	}
 
 	return rv;
-
 }
 
 bool
@@ -480,11 +463,18 @@ MPU9250_mag::ak8963_setup_master_i2c(void)
 	 * in master mode (SPI to I2C bridge)
 	 */
 	if (_interface == nullptr) {
-		_parent->modify_checked_reg(MPUREG_USER_CTRL, 0, BIT_I2C_MST_EN);
+		if (_parent->_device_type == MPU_DEVICE_TYPE_MPU9250) {
-		_parent->write_reg(MPUREG_I2C_MST_CTRL, BIT_I2C_MST_P_NSR | BIT_I2C_MST_WAIT_FOR_ES | BITS_I2C_MST_CLOCK_400HZ);
+			_parent->modify_checked_reg(MPUREG_USER_CTRL, 0, BIT_I2C_MST_EN);
+			_parent->write_reg(MPUREG_I2C_MST_CTRL, BIT_I2C_MST_P_NSR | BIT_I2C_MST_WAIT_FOR_ES | BITS_I2C_MST_CLOCK_400HZ);
+
+		} else { // ICM20948 -> AK09916
+			_parent->modify_checked_reg(ICMREG_20948_USER_CTRL, 0, BIT_I2C_MST_EN);
+			// WAIT_FOR_ES does not exist for ICM20948. Not sure how to replace this (or if that is needed)
+			_parent->write_reg(ICMREG_20948_I2C_MST_CTRL, BIT_I2C_MST_P_NSR | ICM_BITS_I2C_MST_CLOCK_400HZ);
+		}
 
 	} else {
-		_parent->modify_checked_reg(MPUREG_USER_CTRL, BIT_I2C_MST_EN, 0);
+		_parent->modify_checked_reg(AK_MPU_OR_ICM(MPUREG_USER_CTRL, ICMREG_20948_USER_CTRL), BIT_I2C_MST_EN, 0);
 	}
 
 	return OK;
@@ -497,7 +487,7 @@ MPU9250_mag::ak8963_setup(void)
 	do {
 
 		ak8963_setup_master_i2c();
-		write_reg(AK8963REG_CNTL2, AK8963_RESET);
+		write_reg(AK_MPU_OR_ICM(AK8963REG_CNTL2, AK09916REG_CNTL3), AK8963_RESET);
 
 		uint8_t id = 0;
 
@@ -506,33 +496,41 @@ MPU9250_mag::ak8963_setup(void)
 		}
 
 		retries--;
-		PX4_ERR("AK8963: bad id %d retries %d", id, retries);
+		PX4_WARN("AK8963: bad id %d retries %d", id, retries);
-		_parent->modify_reg(MPUREG_USER_CTRL, 0, BIT_I2C_MST_RST);
+		_parent->modify_reg(AK_MPU_OR_ICM(MPUREG_USER_CTRL, ICMREG_20948_USER_CTRL), 0, BIT_I2C_MST_RST);
 		up_udelay(100);
 	} while (retries > 0);
 
-	if (retries > 0) {
+	/* No sensitivity adjustments available for AK09916/ICM20948 */
-		retries = 10;
+	if (_parent->_device_type == MPU_DEVICE_TYPE_MPU9250) {
+		if (retries > 0) {
+			retries = 10;
 
-		while (!ak8963_read_adjustments() && retries) {
+			while (!ak8963_read_adjustments() && retries) {
-			retries--;
+				retries--;
-			PX4_ERR("AK8963: failed to read adjustment data. Retries %d", retries);
+				PX4_ERR("AK8963: failed to read adjustment data. Retries %d", retries);
 
-			_parent->modify_reg(MPUREG_USER_CTRL, 0, BIT_I2C_MST_RST);
+				_parent->modify_reg(AK_MPU_OR_ICM(MPUREG_USER_CTRL, ICMREG_20948_USER_CTRL), 0, BIT_I2C_MST_RST);
-			up_udelay(100);
+				up_udelay(100);
-			ak8963_setup_master_i2c();
+				ak8963_setup_master_i2c();
-			write_reg(AK8963REG_CNTL2, AK8963_RESET);
+				write_reg(AK_MPU_OR_ICM(AK8963REG_CNTL2, AK09916REG_CNTL3), AK8963_RESET);
+			}
 		}
 	}
 
 	if (retries == 0) {
 		PX4_ERR("AK8963: failed to initialize, disabled!");
-		_parent->modify_checked_reg(MPUREG_USER_CTRL, BIT_I2C_MST_EN, 0);
+		_parent->modify_checked_reg(AK_MPU_OR_ICM(MPUREG_USER_CTRL, ICMREG_20948_USER_CTRL), BIT_I2C_MST_EN, 0);
-		_parent->write_reg(MPUREG_I2C_MST_CTRL, 0);
+		_parent->write_reg(AK_MPU_OR_ICM(MPUREG_I2C_MST_CTRL, ICMREG_20948_I2C_MST_CTRL), 0);
 		return -EIO;
 	}
 
-	write_reg(AK8963REG_CNTL1, AK8963_CONTINUOUS_MODE2 | AK8963_16BIT_ADC);
+	if (_parent->_device_type == MPU_DEVICE_TYPE_MPU9250) {
+		write_reg(AK8963REG_CNTL1, AK8963_CONTINUOUS_MODE2 | AK8963_16BIT_ADC);
+
+	} else { // ICM20948 -> AK09916
+		write_reg(AK09916REG_CNTL2, AK09916_CNTL2_CONTINOUS_MODE_100HZ);
+	}
 
 
 	if (_interface == NULL) {
@@ -540,7 +538,13 @@ MPU9250_mag::ak8963_setup(void)
 		/* Configure mpu' I2c Master interface to read ak8963 data
 		 * Into to fifo
 		 */
-		set_passthrough(AK8963REG_ST1, sizeof(struct ak8963_regs));
+		if (_parent->_device_type == MPU_DEVICE_TYPE_MPU9250) {
+			set_passthrough(AK8963REG_ST1, sizeof(struct ak8963_regs));
+
+		} else { // ICM20948 -> AK09916
+			set_passthrough(AK09916REG_ST1, sizeof(struct ak09916_regs));
+		}
+
 	}
 
 	return OK;

src/drivers/imu/mpu9250/mag.h

@@ -66,6 +66,38 @@
 #define AK8963_16BIT_ADC        0x10
 #define AK8963_14BIT_ADC        0x00
 #define AK8963_RESET            0x01
+#define AK8963_HOFL             0x08
+
+/* ak09916 deviating register addresses and bit definitions */
+
+#define AK09916_DEVICE_ID_A		0x48	// same as AK8963
+#define AK09916_DEVICE_ID_B		0x09	// additional ID byte ("INFO" on AK9063 without content specification.)
+
+#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_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
+
+
+#define AK_MPU_OR_ICM(m,i)					((_parent->_device_type==MPU_DEVICE_TYPE_MPU9250) ? (m) : (i))
 
 
 
@@ -81,6 +113,18 @@ struct ak8963_regs {
 };
 #pragma pack(pop)
 
+#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)
+
+
 extern device::Device *AK8963_I2C_interface(int bus, bool external_bus);
 
 typedef device::Device *(*MPU9250_mag_constructor)(int, bool);
@@ -95,7 +139,6 @@ public:
 	MPU9250_mag(MPU9250 *parent, device::Device *interface, const char *path);
 	~MPU9250_mag();
 
-	virtual ssize_t read(struct file *filp, char *buffer, size_t buflen);
 	virtual int ioctl(struct file *filp, int cmd, unsigned long arg);
 	virtual int init();
 
@@ -121,15 +164,11 @@ protected:
 	/* Update the state with prefetched data (internally called by the regular measure() )*/
 	void _measure(struct ak8963_regs data);
 
-
 	uint8_t read_reg(unsigned reg);
 	void write_reg(unsigned reg, uint8_t value);
 
-
 	bool is_passthrough() { return _interface == nullptr; }
 
-	int self_test(void);
-
 private:
 	MPU9250 *_parent;
 	orb_advert_t _mag_topic;

src/drivers/imu/mpu9250/mag_i2c.cpp

@@ -102,7 +102,7 @@ AK8963_I2C::probe()
 	uint8_t whoami = 0;
 	uint8_t expected = AK8963_DEVICE_ID;
 
-	if (read(AK8963REG_WIA, &whoami, 1)) {
+	if (PX4_OK != read(AK8963REG_WIA, &whoami, 1)) {
 		return -EIO;
 	}
 

src/drivers/imu/mpu9250/main.cpp

@@ -91,10 +91,33 @@
 #define MPU_DEVICE_PATH_GYRO_EXT2	"/dev/mpu9250_gyro_ext2"
 #define MPU_DEVICE_PATH_MAG_EXT2	"/dev/mpu9250_mag_ext2"
 
+#define MPU_DEVICE_PATH_MPU6500_ACCEL       "/dev/mpu6500_accel"
+#define MPU_DEVICE_PATH_MPU6500_GYRO        "/dev/mpu6500_gyro"
+#define MPU_DEVICE_PATH_MPU6500_MAG         "/dev/mpu6500_mag"
+
+#define MPU_DEVICE_PATH_MPU6500_ACCEL_1     "/dev/mpu6500_accel1"
+#define MPU_DEVICE_PATH_MPU6500_GYRO_1      "/dev/mpu6500_gyro1"
+#define MPU_DEVICE_PATH_MPU6500_MAG_1       "/dev/mpu6500_mag1"
+
+#define MPU_DEVICE_PATH_MPU6500_ACCEL_EXT   "/dev/mpu6500_accel_ext"
+#define MPU_DEVICE_PATH_MPU6500_GYRO_EXT    "/dev/mpu6500_gyro_ext"
+#define MPU_DEVICE_PATH_MPU6500_MAG_EXT     "/dev/mpu6500_mag_ext"
+
+#define MPU_DEVICE_PATH_ICM_ACCEL_EXT  "/dev/mpu9250_icm_accel_ext"
+#define MPU_DEVICE_PATH_ICM_GYRO_EXT   "/dev/mpu9250_icm_gyro_ext"
+#define MPU_DEVICE_PATH_ICM_MAG_EXT    "/dev/mpu9250_icm_mag_ext"
+
+#define MPU_DEVICE_PATH_ICM_ACCEL_EXT1	"/dev/mpu9250_icm_accel_ext1"
+#define MPU_DEVICE_PATH_ICM_GYRO_EXT1	"/dev/mpu9250_icm_gyro_ext1"
+#define MPU_DEVICE_PATH_ICM_MAG_EXT1 	"/dev/mpu9250_icm_mag_ext1"
+
+#define MPU_DEVICE_PATH_ICM_ACCEL_EXT2	"/dev/mpu9250_icm_accel_ext2"
+#define MPU_DEVICE_PATH_ICM_GYRO_EXT2	"/dev/mpu9250_icm_gyro_ext2"
+#define MPU_DEVICE_PATH_ICM_MAG_EXT2	"/dev/mpu9250_icm_mag_ext2"
+
 /** driver 'main' command */
 extern "C" { __EXPORT int mpu9250_main(int argc, char *argv[]); }
 
-
 enum MPU9250_BUS {
 	MPU9250_BUS_ALL = 0,
 	MPU9250_BUS_I2C_INTERNAL,
@@ -104,7 +127,6 @@ enum MPU9250_BUS {
 	MPU9250_BUS_SPI_EXTERNAL
 };
 
-
 /**
  * Local functions in support of the shell command.
  */
@@ -117,6 +139,7 @@ namespace mpu9250
 
 struct mpu9250_bus_option {
 	enum MPU9250_BUS busid;
+	MPU_DEVICE_TYPE device_type;
 	const char *accelpath;
 	const char *gyropath;
 	const char *magpath;
@@ -127,42 +150,47 @@ struct mpu9250_bus_option {
 	MPU9250	*dev;
 } bus_options[] = {
 #if defined (USE_I2C)
-#  if defined(PX4_I2C_BUS_ONBOARD)
+#  if defined(PX4_I2C_BUS_ONBOARD) && defined(PX4_I2C_OBDEV_MPU9250)
-	{ MPU9250_BUS_I2C_INTERNAL, MPU_DEVICE_PATH_ACCEL, MPU_DEVICE_PATH_GYRO, MPU_DEVICE_PATH_MAG,  &MPU9250_I2C_interface, false, PX4_I2C_BUS_ONBOARD, PX4_I2C_OBDEV_MPU9250, NULL },
+	{ MPU9250_BUS_I2C_INTERNAL, MPU_DEVICE_TYPE_MPU9250, MPU_DEVICE_PATH_ACCEL, MPU_DEVICE_PATH_GYRO, MPU_DEVICE_PATH_MAG,  &MPU9250_I2C_interface, false, PX4_I2C_BUS_ONBOARD, PX4_I2C_OBDEV_MPU9250, NULL },
+	{ MPU9250_BUS_I2C_INTERNAL, MPU_DEVICE_TYPE_MPU6500, MPU_DEVICE_PATH_ACCEL, MPU_DEVICE_PATH_GYRO, MPU_DEVICE_PATH_MAG,  &MPU9250_I2C_interface, false, PX4_I2C_BUS_ONBOARD, PX4_I2C_OBDEV_MPU9250, NULL },
 #  endif
 #  if defined(PX4_I2C_BUS_EXPANSION)
-	{ MPU9250_BUS_I2C_EXTERNAL, MPU_DEVICE_PATH_ACCEL_EXT, MPU_DEVICE_PATH_GYRO_EXT, MPU_DEVICE_PATH_MAG_EXT, &MPU9250_I2C_interface, false, PX4_I2C_BUS_EXPANSION, PX4_I2C_OBDEV_MPU9250, NULL },
+#  if defined(PX4_I2C_OBDEV_MPU9250)
+	{ MPU9250_BUS_I2C_EXTERNAL, MPU_DEVICE_TYPE_MPU9250, MPU_DEVICE_PATH_ACCEL_EXT, MPU_DEVICE_PATH_GYRO_EXT, MPU_DEVICE_PATH_MAG_EXT, &MPU9250_I2C_interface, false, PX4_I2C_BUS_EXPANSION, PX4_I2C_OBDEV_MPU9250, NULL },
+	{ MPU9250_BUS_I2C_EXTERNAL, MPU_DEVICE_TYPE_MPU6500, MPU_DEVICE_PATH_ACCEL_EXT, MPU_DEVICE_PATH_GYRO_EXT, MPU_DEVICE_PATH_MAG_EXT, &MPU9250_I2C_interface, false, PX4_I2C_BUS_EXPANSION, PX4_I2C_OBDEV_MPU9250, NULL },
 #  endif
-#  if defined(PX4_I2C_BUS_EXPANSION1)
+	{ MPU9250_BUS_I2C_EXTERNAL, MPU_DEVICE_TYPE_ICM20948, MPU_DEVICE_PATH_ICM_ACCEL_EXT, MPU_DEVICE_PATH_ICM_GYRO_EXT, MPU_DEVICE_PATH_ICM_MAG_EXT, &MPU9250_I2C_interface, false, PX4_I2C_BUS_EXPANSION, PX4_I2C_EXT_ICM20948_1, NULL },
+#endif
+#  if defined(PX4_I2C_BUS_EXPANSION1) && defined(PX4_I2C_OBDEV_MPU9250)
 	{ MPU9250_BUS_I2C_EXTERNAL, MPU_DEVICE_PATH_ACCEL_EXT1, MPU_DEVICE_PATH_GYRO_EXT1, MPU_DEVICE_PATH_MAG_EXT1, &MPU9250_I2C_interface, false, PX4_I2C_BUS_EXPANSION1, PX4_I2C_OBDEV_MPU9250, NULL },
 #  endif
-#  if defined(PX4_I2C_BUS_EXPANSION2)
+#  if defined(PX4_I2C_BUS_EXPANSION2) && defined(PX4_I2C_OBDEV_MPU9250)
 	{ MPU9250_BUS_I2C_EXTERNAL, MPU_DEVICE_PATH_ACCEL_EXT2, MPU_DEVICE_PATH_GYRO_EXT2, MPU_DEVICE_PATH_MAG_EXT2, &MPU9250_I2C_interface, false, PX4_I2C_BUS_EXPANSION2, PX4_I2C_OBDEV_MPU9250, NULL },
 #  endif
 #endif
 #ifdef PX4_SPIDEV_MPU
-	{ MPU9250_BUS_SPI_INTERNAL, MPU_DEVICE_PATH_ACCEL, MPU_DEVICE_PATH_GYRO, MPU_DEVICE_PATH_MAG, &MPU9250_SPI_interface, true, PX4_SPI_BUS_SENSORS, PX4_SPIDEV_MPU, NULL },
+	{ MPU9250_BUS_SPI_INTERNAL, MPU_DEVICE_TYPE_MPU9250, MPU_DEVICE_PATH_ACCEL, MPU_DEVICE_PATH_GYRO, MPU_DEVICE_PATH_MAG, &MPU9250_SPI_interface, true, PX4_SPI_BUS_SENSORS, PX4_SPIDEV_MPU, NULL },
+	{ MPU9250_BUS_SPI_INTERNAL, MPU_DEVICE_TYPE_MPU6500, MPU_DEVICE_PATH_MPU6500_ACCEL, MPU_DEVICE_PATH_MPU6500_GYRO, MPU_DEVICE_PATH_MPU6500_MAG, &MPU9250_SPI_interface, true, PX4_SPI_BUS_SENSORS, PX4_SPIDEV_MPU, NULL },
 #endif
 #ifdef PX4_SPIDEV_MPU2
-	{ MPU9250_BUS_SPI_INTERNAL2, MPU_DEVICE_PATH_ACCEL_1, MPU_DEVICE_PATH_GYRO_1, MPU_DEVICE_PATH_MAG_1, &MPU9250_SPI_interface, true, PX4_SPI_BUS_SENSORS, PX4_SPIDEV_MPU2, NULL },
+	{ MPU9250_BUS_SPI_INTERNAL2, MPU_DEVICE_TYPE_MPU9250, MPU_DEVICE_PATH_ACCEL_1, MPU_DEVICE_PATH_GYRO_1, MPU_DEVICE_PATH_MAG_1, &MPU9250_SPI_interface, true, PX4_SPI_BUS_SENSORS, PX4_SPIDEV_MPU2, NULL },
+	{ MPU9250_BUS_SPI_INTERNAL2, MPU_DEVICE_TYPE_MPU6500, MPU_DEVICE_PATH_MPU6500_ACCEL_1, MPU_DEVICE_PATH_MPU6500_GYRO_1, MPU_DEVICE_PATH_MPU6500_MAG_1, &MPU9250_SPI_interface, true, PX4_SPI_BUS_SENSORS, PX4_SPIDEV_MPU2, NULL },
 #endif
 #if defined(PX4_SPI_BUS_EXT) && defined(PX4_SPIDEV_EXT_MPU)
-	{ MPU9250_BUS_SPI_EXTERNAL, MPU_DEVICE_PATH_ACCEL_EXT, MPU_DEVICE_PATH_GYRO_EXT, MPU_DEVICE_PATH_MAG_EXT, &MPU9250_SPI_interface, true, PX4_SPI_BUS_EXT, PX4_SPIDEV_EXT_MPU, NULL },
+	{ MPU9250_BUS_SPI_EXTERNAL, MPU_DEVICE_TYPE_MPU9250, MPU_DEVICE_PATH_ACCEL_EXT, MPU_DEVICE_PATH_GYRO_EXT, MPU_DEVICE_PATH_MAG_EXT, &MPU9250_SPI_interface, true, PX4_SPI_BUS_EXT, PX4_SPIDEV_EXT_MPU, NULL },
+	{ MPU9250_BUS_SPI_EXTERNAL, MPU_DEVICE_TYPE_MPU6500, MPU_DEVICE_PATH_MPU6500_ACCEL_EXT, MPU_DEVICE_PATH_MPU6500_GYRO_EXT, MPU_DEVICE_PATH_MPU6500_MAG_EXT, &MPU9250_SPI_interface, true, PX4_SPI_BUS_EXT, PX4_SPIDEV_EXT_MPU, NULL },
 #endif
 };
 
 #define NUM_BUS_OPTIONS (sizeof(bus_options)/sizeof(bus_options[0]))
 
 
-void	start(enum MPU9250_BUS busid, enum Rotation rotation, bool external_bus);
+void	start(enum MPU9250_BUS busid, enum Rotation rotation, bool external_bus, bool magnetometer_only);
-bool	start_bus(struct mpu9250_bus_option &bus, enum Rotation rotation, bool external_bus);
+bool	start_bus(struct mpu9250_bus_option &bus, enum Rotation rotation, bool external_bus, bool magnetometer_only);
 struct mpu9250_bus_option &find_bus(enum MPU9250_BUS busid);
 void	stop(enum MPU9250_BUS busid);
-void	test(enum MPU9250_BUS busid);
 void	reset(enum MPU9250_BUS busid);
 void	info(enum MPU9250_BUS busid);
-void	regdump(enum MPU9250_BUS busid);
-void	testerror(enum MPU9250_BUS busid);
 void	usage();
 
 /**
@@ -184,16 +212,18 @@ struct mpu9250_bus_option &find_bus(enum MPU9250_BUS busid)
  * start driver for a specific bus option
  */
 bool
-start_bus(struct mpu9250_bus_option &bus, enum Rotation rotation, bool external)
+start_bus(struct mpu9250_bus_option &bus, enum Rotation rotation, bool external, bool magnetometer_only)
 {
 	int fd = -1;
 
+	PX4_INFO("Bus probed: %d", bus.busid);
+
 	if (bus.dev != nullptr) {
 		warnx("%s SPI not available", external ? "External" : "Internal");
 		return false;
 	}
 
-	device::Device *interface = bus.interface_constructor(bus.busnum, bus.address, external);
+	device::Device *interface = bus.interface_constructor(bus.busnum, bus.device_type, bus.address, external);
 
 	if (interface == nullptr) {
 		warnx("no device on bus %u", (unsigned)bus.busid);
@@ -218,10 +248,16 @@ start_bus(struct mpu9250_bus_option &bus, enum Rotation rotation, bool external)
 
 #endif
 
-	bus.dev = new MPU9250(interface, mag_interface, bus.accelpath, bus.gyropath, bus.magpath, rotation);
+	bus.dev = new MPU9250(interface, mag_interface, bus.accelpath, bus.gyropath, bus.magpath, rotation, bus.device_type,
+			      magnetometer_only);
 
 	if (bus.dev == nullptr) {
 		delete interface;
+
+		if (mag_interface != nullptr) {
+			delete mag_interface;
+		}
+
 		return false;
 	}
 
@@ -229,8 +265,17 @@ start_bus(struct mpu9250_bus_option &bus, enum Rotation rotation, bool external)
 		goto fail;
 	}
 
-	/* set the poll rate to default, starts automatic data collection */
+	/*
-	fd = open(bus.accelpath, O_RDONLY);
+	 * Set the poll rate to default, starts automatic data collection.
+	 * Doing this through the mag device for the time being - it's always there, even in magnetometer only mode.
+	 * Using accel device for MPU6500.
+	 */
+	if (bus.device_type == MPU_DEVICE_TYPE_MPU6500) {
+		fd = open(bus.accelpath, O_RDONLY);
+
+	} else {
+		fd = open(bus.magpath, O_RDONLY);
+	}
 
 	if (fd < 0) {
 		goto fail;
@@ -266,7 +311,7 @@ fail:
  * or failed to detect the sensor.
  */
 void
-start(enum MPU9250_BUS busid, enum Rotation rotation, bool external)
+start(enum MPU9250_BUS busid, enum Rotation rotation, bool external, bool magnetometer_only)
 {
 
 	bool started = false;
@@ -282,7 +327,14 @@ start(enum MPU9250_BUS busid, enum Rotation rotation, bool external)
 			continue;
 		}
 
-		started |= start_bus(bus_options[i], rotation, external);
+		if (bus_options[i].device_type == MPU_DEVICE_TYPE_MPU6500 && magnetometer_only) {
+			// prevent starting MPU6500 in magnetometer only mode
+			continue;
+		}
+
+		started |= start_bus(bus_options[i], rotation, external, magnetometer_only);
+
+		if (started) { break; }
 	}
 
 	exit(started ? 0 : 1);
@@ -307,86 +359,6 @@ stop(enum MPU9250_BUS busid)
 	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(enum MPU9250_BUS busid)
-{
-	struct mpu9250_bus_option &bus = find_bus(busid);
-	sensor_accel_s a_report{};
-	sensor_gyro_s g_report{};
-	mag_report m_report;
-	ssize_t sz;
-
-	/* get the driver */
-	int fd = open(bus.accelpath, O_RDONLY);
-
-	if (fd < 0) {
-		err(1, "%s open failed (try 'm start')", bus.accelpath);
-	}
-
-	/* get the driver */
-	int fd_gyro = open(bus.gyropath, O_RDONLY);
-
-	if (fd_gyro < 0) {
-		err(1, "%s open failed", bus.gyropath);
-	}
-
-	/* get the driver */
-	int fd_mag = open(bus.magpath, O_RDONLY);
-
-	if (fd_mag < 0) {
-		err(1, "%s open failed", bus.magpath);
-	}
-
-	/* do a simple demand read */
-	sz = read(fd, &a_report, sizeof(a_report));
-
-	if (sz != sizeof(a_report)) {
-		warnx("ret: %d, expected: %d", sz, sizeof(a_report));
-		err(1, "immediate acc read failed");
-	}
-
-	print_message(a_report);
-
-	/* do a simple demand read */
-	sz = read(fd_gyro, &g_report, sizeof(g_report));
-
-	if (sz != sizeof(g_report)) {
-		warnx("ret: %d, expected: %d", sz, sizeof(g_report));
-		err(1, "immediate gyro read failed");
-	}
-
-	print_message(g_report);
-
-	/* do a simple demand read */
-	sz = read(fd_mag, &m_report, sizeof(m_report));
-
-	if (sz != sizeof(m_report)) {
-		warnx("ret: %d, expected: %d", sz, sizeof(m_report));
-		err(1, "immediate mag read failed");
-	}
-
-	print_message(m_report);
-
-	/* reset to default polling */
-	if (ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT) < 0) {
-		err(1, "reset to default polling");
-	}
-
-	close(fd);
-	close(fd_gyro);
-	close(fd_mag);
-
-	/* XXX add poll-rate tests here too */
-
-	reset(busid);
-	errx(0, "PASS");
-}
-
 /**
  * Reset the driver.
  */
@@ -432,43 +404,6 @@ info(enum MPU9250_BUS busid)
 	exit(0);
 }
 
-/**
- * Dump the register information
- */
-void
-regdump(enum MPU9250_BUS busid)
-{
-	struct mpu9250_bus_option &bus = find_bus(busid);
-
-
-	if (bus.dev == nullptr) {
-		errx(1, "driver not running");
-	}
-
-	printf("regdump @ %p\n", bus.dev);
-	bus.dev->print_registers();
-
-	exit(0);
-}
-
-/**
- * deliberately produce an error to test recovery
- */
-void
-testerror(enum MPU9250_BUS busid)
-{
-	struct mpu9250_bus_option &bus = find_bus(busid);
-
-
-	if (bus.dev == nullptr) {
-		errx(1, "driver not running");
-	}
-
-	bus.dev->test_error();
-
-	exit(0);
-}
-
 void
 usage()
 {
@@ -480,7 +415,7 @@ usage()
 	PX4_INFO("    -S    (spi external bus)");
 	PX4_INFO("    -t    (spi internal bus, 2nd instance)");
 	PX4_INFO("    -R rotation");
-
+	PX4_INFO("    -M only enable magnetometer, accel/gyro disabled - not av. on MPU6500");
 }
 
 } // namespace
@@ -494,8 +429,9 @@ mpu9250_main(int argc, char *argv[])
 
 	enum MPU9250_BUS busid = MPU9250_BUS_ALL;
 	enum Rotation rotation = ROTATION_NONE;
+	bool magnetometer_only = false;
 
-	while ((ch = px4_getopt(argc, argv, "XISstR:", &myoptind, &myoptarg)) != EOF) {
+	while ((ch = px4_getopt(argc, argv, "XISstMR:", &myoptind, &myoptarg)) != EOF) {
 		switch (ch) {
 		case 'X':
 			busid = MPU9250_BUS_I2C_EXTERNAL;
@@ -521,6 +457,10 @@ mpu9250_main(int argc, char *argv[])
 			rotation = (enum Rotation)atoi(myoptarg);
 			break;
 
+		case 'M':
+			magnetometer_only = true;
+			break;
+
 		default:
 			mpu9250::usage();
 			return 0;
@@ -539,20 +479,13 @@ mpu9250_main(int argc, char *argv[])
 	 * Start/load the driver.
 	 */
 	if (!strcmp(verb, "start")) {
-		mpu9250::start(busid, rotation, external);
+		mpu9250::start(busid, rotation, external, magnetometer_only);
 	}
 
 	if (!strcmp(verb, "stop")) {
 		mpu9250::stop(busid);
 	}
 
-	/*
-	 * Test the driver/device.
-	 */
-	if (!strcmp(verb, "test")) {
-		mpu9250::test(busid);
-	}
-
 	/*
 	 * Reset the driver.
 	 */
@@ -567,17 +500,6 @@ mpu9250_main(int argc, char *argv[])
 		mpu9250::info(busid);
 	}
 
-	/*
-	 * Print register information.
-	 */
-	if (!strcmp(verb, "regdump")) {
-		mpu9250::regdump(busid);
-	}
-
-	if (!strcmp(verb, "testerror")) {
-		mpu9250::testerror(busid);
-	}
-
 	mpu9250::usage();
 	return 0;
 }

src/drivers/imu/mpu9250/mpu9250.h

@@ -49,12 +49,23 @@
 #include <mathlib/math/filter/LowPassFilter2p.hpp>
 #include <lib/conversion/rotation.h>
 
+#include <uORB/uORB.h>
+#include <uORB/topics/debug_key_value.h>
+
 #include "mag.h"
+#include "accel.h"
 #include "gyro.h"
 
 
+/* List of supported device types */
+enum MPU_DEVICE_TYPE {
+	MPU_DEVICE_TYPE_MPU9250	= 9250,
+	MPU_DEVICE_TYPE_MPU6500 = 6500,
+	MPU_DEVICE_TYPE_ICM20948 = 20948
+};
 
-#if defined(PX4_I2C_OBDEV_MPU9250)
+
+#if defined(PX4_I2C_OBDEV_MPU9250) || defined(PX4_I2C_BUS_EXPANSION)
 #  define USE_I2C
 #endif
 
@@ -177,8 +188,9 @@
 #define BIT_I2C_SLV2_DLY_EN         0x04
 #define BIT_I2C_SLV3_DLY_EN         0x08
 
-#define MPU_WHOAMI_9250			0x71
+#define MPU_WHOAMI_9250             0x71
-#define MPU_WHOAMI_6500			0x70
+#define MPU_WHOAMI_6500             0x70
+#define ICM_WHOAMI_20948            0xEA
 
 #define MPU9250_ACCEL_DEFAULT_RATE	1000
 #define MPU9250_ACCEL_MAX_OUTPUT_RATE			280
@@ -193,6 +205,135 @@
 #define MPUIOCGIS_I2C	(unsigned)(DEVIOCGDEVICEID+100)
 
 
+
+// ICM20948 registers and data
+
+/*
+ * ICM20948 I2C address LSB can be switched by the chip's AD0 pin, thus is device dependent.
+ * Noting this down for now. Here GPS uses 0x69. To support a device implementing the second
+ * address, probably an additional MPU_DEVICE_TYPE is the way to go.
+ */
+#define PX4_I2C_EXT_ICM20948_0			0x68
+#define PX4_I2C_EXT_ICM20948_1			0x69
+
+/*
+ * ICM20948 uses register banks. Register 127 (0x7F) is used to switch between 4 banks.
+ * There's room in the upper address byte below the port speed setting to code in the
+ * used bank. This is a bit more efficient, already in use for the speed setting and more
+ * in one place than a solution with a lookup table for address/bank pairs.
+ */
+
+#define BANK0	0x0000
+#define BANK1	0x0100
+#define BANK2	0x0200
+#define BANK3	0x0300
+
+#define BANK_REG_MASK	0x0300
+#define REG_BANK(r) 			(((r) & BANK_REG_MASK)>>4)
+#define REG_ADDRESS(r)			((r) & ~BANK_REG_MASK)
+
+#define ICMREG_20948_BANK_SEL 0x7F
+
+#define	ICMREG_20948_WHOAMI					(0x00 | BANK0)
+#define ICMREG_20948_USER_CTRL				(0x03 | BANK0)
+#define ICMREG_20948_PWR_MGMT_1				(0x06 | BANK0)
+#define ICMREG_20948_PWR_MGMT_2				(0x07 | BANK0)
+#define ICMREG_20948_INT_PIN_CFG			(0x0F | BANK0)
+#define ICMREG_20948_INT_ENABLE				(0x10 | BANK0)
+#define ICMREG_20948_INT_ENABLE_1			(0x11 | BANK0)
+#define ICMREG_20948_ACCEL_XOUT_H			(0x2D | BANK0)
+#define ICMREG_20948_INT_ENABLE_2			(0x12 | BANK0)
+#define ICMREG_20948_INT_ENABLE_3			(0x13 | BANK0)
+#define ICMREG_20948_EXT_SLV_SENS_DATA_00	(0x3B | BANK0)
+#define ICMREG_20948_GYRO_SMPLRT_DIV		(0x00 | BANK2)
+#define ICMREG_20948_GYRO_CONFIG_1			(0x01 | BANK2)
+#define ICMREG_20948_GYRO_CONFIG_2			(0x02 | BANK2)
+#define ICMREG_20948_ACCEL_SMPLRT_DIV_1		(0x10 | BANK2)
+#define ICMREG_20948_ACCEL_SMPLRT_DIV_2		(0x11 | BANK2)
+#define ICMREG_20948_ACCEL_CONFIG			(0x14 | BANK2)
+#define ICMREG_20948_ACCEL_CONFIG_2			(0x15 | BANK2)
+#define ICMREG_20948_I2C_MST_CTRL			(0x01 | BANK3)
+#define ICMREG_20948_I2C_SLV0_ADDR			(0x03 | BANK3)
+#define ICMREG_20948_I2C_SLV0_REG			(0x04 | BANK3)
+#define ICMREG_20948_I2C_SLV0_CTRL			(0x05 | BANK3)
+#define ICMREG_20948_I2C_SLV0_DO			(0x06 | BANK3)
+
+
+
+/*
+* ICM20948 register bits
+* Most of the regiser set values from MPU9250 have the same
+* meaning on ICM20948. The exceptions and values not already
+* defined for MPU9250 are defined below
+*/
+#define ICM_BIT_PWR_MGMT_1_ENABLE       	0x00
+#define ICM_BIT_USER_CTRL_I2C_MST_DISABLE   0x00
+
+#define ICM_BITS_GYRO_DLPF_CFG_197HZ		0x01
+#define ICM_BITS_GYRO_DLPF_CFG_151HZ		0x09
+#define ICM_BITS_GYRO_DLPF_CFG_119HZ		0x11
+#define ICM_BITS_GYRO_DLPF_CFG_51HZ			0x19
+#define ICM_BITS_GYRO_DLPF_CFG_23HZ			0x21
+#define ICM_BITS_GYRO_DLPF_CFG_11HZ			0x29
+#define ICM_BITS_GYRO_DLPF_CFG_5HZ			0x31
+#define ICM_BITS_GYRO_DLPF_CFG_361HZ		0x39
+#define ICM_BITS_GYRO_DLPF_CFG_MASK			0x39
+
+#define ICM_BITS_GYRO_FS_SEL_250DPS			0x00
+#define ICM_BITS_GYRO_FS_SEL_500DPS			0x02
+#define ICM_BITS_GYRO_FS_SEL_1000DPS		0x04
+#define ICM_BITS_GYRO_FS_SEL_2000DPS		0x06
+#define ICM_BITS_GYRO_FS_SEL_MASK			0x06
+
+#define ICM_BITS_ACCEL_DLPF_CFG_246HZ		0x09
+#define ICM_BITS_ACCEL_DLPF_CFG_111HZ		0x11
+#define ICM_BITS_ACCEL_DLPF_CFG_50HZ		0x19
+#define ICM_BITS_ACCEL_DLPF_CFG_23HZ		0x21
+#define ICM_BITS_ACCEL_DLPF_CFG_11HZ		0x29
+#define ICM_BITS_ACCEL_DLPF_CFG_5HZ			0x31
+#define ICM_BITS_ACCEL_DLPF_CFG_473HZ		0x39
+#define ICM_BITS_ACCEL_DLPF_CFG_MASK		0x39
+
+#define ICM_BITS_ACCEL_FS_SEL_250DPS		0x00
+#define ICM_BITS_ACCEL_FS_SEL_500DPS		0x02
+#define ICM_BITS_ACCEL_FS_SEL_1000DPS		0x04
+#define ICM_BITS_ACCEL_FS_SEL_2000DPS		0x06
+#define ICM_BITS_ACCEL_FS_SEL_MASK			0x06
+
+#define ICM_BITS_DEC3_CFG_4					0x00
+#define ICM_BITS_DEC3_CFG_8					0x01
+#define ICM_BITS_DEC3_CFG_16				0x10
+#define ICM_BITS_DEC3_CFG_32				0x11
+#define ICM_BITS_DEC3_CFG_MASK				0x11
+
+#define ICM_BITS_I2C_MST_CLOCK_370KHZ    	0x00
+#define ICM_BITS_I2C_MST_CLOCK_400HZ    	0x07	// recommended by datasheet for 400kHz target clock
+
+
+
+#define MPU_OR_ICM(m,i)					((_device_type==MPU_DEVICE_TYPE_ICM20948) ? i : m)
+
+
+#pragma pack(push, 1)
+/**
+ * Report conversation within the mpu, including command byte and
+ * interrupt status.
+ */
+struct ICMReport {
+	uint8_t		accel_x[2];
+	uint8_t		accel_y[2];
+	uint8_t		accel_z[2];
+	uint8_t		gyro_x[2];
+	uint8_t		gyro_y[2];
+	uint8_t		gyro_z[2];
+	uint8_t		temp[2];
+	struct ak8963_regs mag;
+};
+#pragma pack(pop)
+
+
+
+
 #pragma pack(push, 1)
 /**
  * Report conversation within the mpu, including command byte and
@@ -224,71 +365,71 @@ struct MPUReport {
  */
 #define MPU9250_LOW_BUS_SPEED				0
 #define MPU9250_HIGH_BUS_SPEED				0x8000
+#define MPU9250_REG_MASK					0x00FF
 #  define MPU9250_IS_HIGH_SPEED(r) 			((r) & MPU9250_HIGH_BUS_SPEED)
-#  define MPU9250_REG(r) 					((r) &~MPU9250_HIGH_BUS_SPEED)
+#  define MPU9250_REG(r) 					((r) & MPU9250_REG_MASK)
 #  define MPU9250_SET_SPEED(r, s) 			((r)|(s))
 #  define MPU9250_HIGH_SPEED_OP(r) 			MPU9250_SET_SPEED((r), MPU9250_HIGH_BUS_SPEED)
-#  define MPU9250_LOW_SPEED_OP(r)			MPU9250_REG((r))
+#  define MPU9250_LOW_SPEED_OP(r)			((r) &~MPU9250_HIGH_BUS_SPEED)
 
 /* interface factories */
-extern device::Device *MPU9250_SPI_interface(int bus, uint32_t cs, bool external_bus);
+extern device::Device *MPU9250_SPI_interface(int bus, int device_type, uint32_t cs, bool external_bus);
-extern device::Device *MPU9250_I2C_interface(int bus, uint32_t address, bool external_bus);
+extern device::Device *MPU9250_I2C_interface(int bus, int device_type, uint32_t address, bool external_bus);
 extern int MPU9250_probe(device::Device *dev, int device_type);
 
-typedef device::Device *(*MPU9250_constructor)(int, uint32_t, bool);
+typedef device::Device *(*MPU9250_constructor)(int, int, uint32_t, bool);
 
 class MPU9250_mag;
+class MPU9250_accel;
 class MPU9250_gyro;
 
-class MPU9250 : public device::CDev
+class MPU9250
 {
 public:
 	MPU9250(device::Device *interface, device::Device *mag_interface, const char *path_accel, const char *path_gyro,
 		const char *path_mag,
-		enum Rotation rotation);
+		enum Rotation rotation,
+		int device_type,
+		bool magnetometer_only);
+
 	virtual ~MPU9250();
 
 	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();
 
-	void			print_registers();
-
-	// deliberately cause a sensor error
-	void 			test_error();
-
 protected:
-	Device			*_interface;
+	device::Device *_interface;
 
 	virtual int		probe();
 
+	friend class MPU9250_accel;
 	friend class MPU9250_mag;
 	friend class MPU9250_gyro;
 
-	virtual ssize_t		gyro_read(struct file *filp, char *buffer, size_t buflen);
-	virtual int		gyro_ioctl(struct file *filp, int cmd, unsigned long arg);
-
 private:
+	MPU9250_accel   *_accel;
 	MPU9250_gyro	*_gyro;
 	MPU9250_mag     *_mag;
 	uint8_t			_whoami;	/** whoami result */
+	int 			_device_type;
+	uint8_t 		_selected_bank;			/* Remember selected memory bank to avoid polling / setting on each read/write */
+	bool
+	_magnetometer_only;     /* To disable accel and gyro reporting if only magnetometer is used (e.g. as external magnetometer) */
 
 #if defined(USE_I2C)
 	/*
 	 * SPI bus based device use hrt
 	 * I2C bus needs to use work queue
 	 */
-	work_s			_work;
+	work_s			_work{};
 #endif
 	bool 			_use_hrt;
 
-	struct hrt_call		_call;
+	struct hrt_call		_call {};
 	unsigned		_call_interval;
 
 	ringbuffer::RingBuffer	*_accel_reports;
@@ -297,8 +438,6 @@ private:
 	float			_accel_range_scale;
 	float			_accel_range_m_s2;
 	orb_advert_t		_accel_topic;
-	int			_accel_orb_class_instance;
-	int			_accel_class_instance;
 
 	ringbuffer::RingBuffer	*_gyro_reports;
 
@@ -307,6 +446,8 @@ private:
 	float			_gyro_range_rad_s;
 
 	unsigned		_dlpf_freq;
+	unsigned		_dlpf_freq_icm_gyro;
+	unsigned		_dlpf_freq_icm_accel;
 
 	unsigned		_sample_rate;
 	perf_counter_t		_accel_reads;
@@ -336,16 +477,28 @@ private:
 	// this is used to support runtime checking of key
 	// configuration registers to detect SPI bus errors and sensor
 	// reset
+
+#ifndef MAX
+#define MAX(X,Y) ((X) > (Y) ? (X) : (Y))
+#endif
+
 #define MPU9250_NUM_CHECKED_REGISTERS 11
-	static const uint8_t	_checked_registers[MPU9250_NUM_CHECKED_REGISTERS];
+	static const uint16_t	_mpu9250_checked_registers[MPU9250_NUM_CHECKED_REGISTERS];
-	uint8_t			_checked_values[MPU9250_NUM_CHECKED_REGISTERS];
+#define ICM20948_NUM_CHECKED_REGISTERS 15
-	uint8_t			_checked_bad[MPU9250_NUM_CHECKED_REGISTERS];
+	static const uint16_t	_icm20948_checked_registers[ICM20948_NUM_CHECKED_REGISTERS];
-	uint8_t			_checked_next;
+
+	const uint16_t			*_checked_registers;
+
+	uint8_t					_checked_values[MAX(MPU9250_NUM_CHECKED_REGISTERS, ICM20948_NUM_CHECKED_REGISTERS)];
+	uint8_t					_checked_bad[MAX(MPU9250_NUM_CHECKED_REGISTERS, ICM20948_NUM_CHECKED_REGISTERS)];
+	unsigned				_checked_next;
+	unsigned				_num_checked_registers;
+
 
 	// last temperature reading for print_info()
 	float			_last_temperature;
 
-	bool check_null_data(uint32_t *data, uint8_t size);
+	bool check_null_data(uint16_t *data, uint8_t size);
 	bool check_duplicate(uint8_t *accel_data);
 	// keep last accel reading for duplicate detection
 	uint8_t			_last_accel_data[6];
@@ -425,15 +578,40 @@ private:
 	 */
 	void			measure();
 
+	/**
+	 * Select a register bank in ICM20948
+	 *
+	 * Only actually switches if the remembered bank is different from the
+	 * requested one
+	 *
+	 * @param		The index of the register bank to switch to (0-3)
+	 * @return		Error code
+	 */
+	int				select_register_bank(uint8_t bank);
+
+
 	/**
 	 * Read a register from the mpu
 	 *
 	 * @param		The register to read.
+	* @param       The bus speed to read with.
 	 * @return		The value that was read.
 	 */
 	uint8_t			read_reg(unsigned reg, uint32_t speed = MPU9250_LOW_BUS_SPEED);
 	uint16_t		read_reg16(unsigned reg);
 
+
+	/**
+	 * Read a register range from the mpu
+	 *
+	 * @param       The start address to read from.
+	 * @param       The bus speed to read with.
+	 * @param       The address of the target data buffer.
+	 * @param       The count of bytes to be read.
+	 * @return      The value that was read.
+	 */
+	uint8_t read_reg_range(unsigned start_reg, uint32_t speed, uint8_t *buf, uint16_t count);
+
 	/**
 	 * Write a register in the mpu
 	 *
@@ -492,13 +670,6 @@ private:
 	 */
 	bool			is_external() { return _interface->external(); }
 
-	/**
-	 * Measurement self test
-	 *
-	 * @return 0 on success, 1 on failure
-	 */
-	int 			self_test();
-
 	/*
 	  set low pass filter frequency
 	 */
@@ -509,6 +680,11 @@ private:
 	*/
 	void _set_sample_rate(unsigned desired_sample_rate_hz);
 
+	/*
+	  set poll rate
+	 */
+	int _set_pollrate(unsigned long rate);
+
 	/*
 	  check that key registers still have the right value
 	 */

src/drivers/imu/mpu9250/mpu9250_i2c.cpp

@@ -46,30 +46,34 @@
 
 #ifdef USE_I2C
 
-device::Device *MPU9250_I2C_interface(int bus, uint32_t address, bool external_bus);
+device::Device *MPU9250_I2C_interface(int bus, int device_type, uint32_t address, bool external_bus);
 
 class MPU9250_I2C : public device::I2C
 {
 public:
-	MPU9250_I2C(int bus, uint32_t address);
+	MPU9250_I2C(int bus, int device_type, uint32_t address);
 	~MPU9250_I2C() override = default;
 
 	int	read(unsigned address, void *data, unsigned count) override;
 	int	write(unsigned address, void *data, unsigned count) override;
 
 protected:
-	int	probe() override;
+	virtual int	probe();
+
+private:
+	int 		_device_type;
 
 };
 
 device::Device *
-MPU9250_I2C_interface(int bus, uint32_t address, bool external_bus)
+MPU9250_I2C_interface(int bus, int device_type, uint32_t address, bool external_bus)
 {
-	return new MPU9250_I2C(bus, address);
+	return new MPU9250_I2C(bus, device_type, address);
 }
 
-MPU9250_I2C::MPU9250_I2C(int bus, uint32_t address) :
+MPU9250_I2C::MPU9250_I2C(int bus, int device_type, uint32_t address) :
-	I2C("MPU9250_I2C", nullptr, bus, address, 400000)
+	I2C("MPU9250_I2C", nullptr, bus, address, 400000),
+	_device_type(device_type)
 {
 	_device_id.devid_s.devtype = DRV_ACC_DEVTYPE_MPU9250;
 }
@@ -106,8 +110,34 @@ int
 MPU9250_I2C::probe()
 {
 	uint8_t whoami = 0;
-	uint8_t expected = MPU_WHOAMI_9250;
+	uint8_t reg_whoami = 0;
-	return (read(MPUREG_WHOAMI, &whoami, 1) == OK && (whoami == expected)) ? 0 : -EIO;
+	uint8_t expected = 0;
+	uint8_t register_select = REG_BANK(BANK0);  // register bank containing WHOAMI for ICM20948
+
+	switch (_device_type) {
+	case MPU_DEVICE_TYPE_MPU9250:
+		reg_whoami = MPUREG_WHOAMI;
+		expected = MPU_WHOAMI_9250;
+		break;
+
+	case MPU_DEVICE_TYPE_MPU6500:
+		reg_whoami = MPUREG_WHOAMI;
+		expected = MPU_WHOAMI_6500;
+		break;
+
+	case MPU_DEVICE_TYPE_ICM20948:
+		reg_whoami = ICMREG_20948_WHOAMI;
+		expected = ICM_WHOAMI_20948;
+		/*
+		 * make sure register bank 0 is selected - whoami is only present on bank 0, and that is
+		 * not sure e.g. if the device has rebooted without repowering the sensor
+		 */
+		write(ICMREG_20948_BANK_SEL, &register_select, 1);
+
+		break;
+	}
+
+	return (read(reg_whoami, &whoami, 1) == OK && (whoami == expected)) ? 0 : -EIO;
 }
 
 #endif /* USE_I2C */

src/drivers/imu/mpu9250/mpu9250_spi.cpp

@@ -63,7 +63,7 @@
 #define MPU9250_LOW_SPI_BUS_SPEED	1000*1000
 #define MPU9250_HIGH_SPI_BUS_SPEED	20*1000*1000
 
-device::Device *MPU9250_SPI_interface(int bus, uint32_t cs, bool external_bus);
+device::Device *MPU9250_SPI_interface(int bus, int device_type, uint32_t cs, bool external_bus);
 
 class MPU9250_SPI : public device::SPI
 {
@@ -84,7 +84,7 @@ private:
 };
 
 device::Device *
-MPU9250_SPI_interface(int bus, uint32_t cs, bool external_bus)
+MPU9250_SPI_interface(int bus, int device_type, uint32_t cs, bool external_bus)
 {
 	device::Device *interface = nullptr;