New-style driver for the MPU6000.

1 files changed, 918 insertions, 0 deletions

diff --git a/apps/drivers/mpu6000/mpu6000.cpp b/apps/drivers/mpu6000/mpu6000.cpp
new file mode 100644
index 000000000..70e3e41c5
--- /dev/null
+++ b/apps/drivers/mpu6000/mpu6000.cpp
@@ -0,0 +1,918 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2012 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 mpu6000.cpp
+ *
+ * Driver for the Invensense MPU6000 connected via SPI.
+ */
+
+#include <nuttx/config.h>
+
+#include <sys/types.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <stddef.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 <systemlib/perf_counter.h>
+
+#include <nuttx/arch.h>
+#include <nuttx/clock.h>
+
+#include <arch/board/board.h>
+#include <arch/board/up_hrt.h>
+
+#include <drivers/device/spi.h>
+#include <drivers/drv_accel.h>
+#include <drivers/drv_gyro.h>
+
+#define DIR_READ			0x80
+#define DIR_WRITE			0x00
+
+// MPU 6000 registers
+#define MPUREG_WHOAMI			0x75
+#define MPUREG_SMPLRT_DIV		0x19
+#define MPUREG_CONFIG			0x1A
+#define MPUREG_GYRO_CONFIG		0x1B
+#define MPUREG_ACCEL_CONFIG		0x1C
+#define MPUREG_FIFO_EN			0x23
+#define MPUREG_INT_PIN_CFG		0x37
+#define MPUREG_INT_ENABLE		0x38
+#define MPUREG_INT_STATUS		0x3A
+#define MPUREG_ACCEL_XOUT_H		0x3B
+#define MPUREG_ACCEL_XOUT_L		0x3C
+#define MPUREG_ACCEL_YOUT_H		0x3D
+#define MPUREG_ACCEL_YOUT_L		0x3E
+#define MPUREG_ACCEL_ZOUT_H		0x3F
+#define MPUREG_ACCEL_ZOUT_L		0x40
+#define MPUREG_TEMP_OUT_H		0x41
+#define MPUREG_TEMP_OUT_L		0x42
+#define MPUREG_GYRO_XOUT_H		0x43
+#define MPUREG_GYRO_XOUT_L		0x44
+#define MPUREG_GYRO_YOUT_H		0x45
+#define MPUREG_GYRO_YOUT_L		0x46
+#define MPUREG_GYRO_ZOUT_H		0x47
+#define MPUREG_GYRO_ZOUT_L		0x48
+#define MPUREG_USER_CTRL		0x6A
+#define MPUREG_PWR_MGMT_1		0x6B
+#define MPUREG_PWR_MGMT_2		0x6C
+#define MPUREG_FIFO_COUNTH		0x72
+#define MPUREG_FIFO_COUNTL		0x73
+#define MPUREG_FIFO_R_W			0x74
+#define MPUREG_PRODUCT_ID		0x0C
+
+// Configuration bits MPU 3000 and MPU 6000 (not revised)?
+#define BIT_SLEEP			0x40
+#define BIT_H_RESET			0x80
+#define BITS_CLKSEL			0x07
+#define MPU_CLK_SEL_PLLGYROX		0x01
+#define MPU_CLK_SEL_PLLGYROZ		0x03
+#define MPU_EXT_SYNC_GYROX		0x02
+#define BITS_FS_250DPS			0x00
+#define BITS_FS_500DPS			0x08
+#define BITS_FS_1000DPS			0x10
+#define BITS_FS_2000DPS			0x18
+#define BITS_FS_MASK			0x18
+#define BITS_DLPF_CFG_256HZ_NOLPF2	0x00
+#define BITS_DLPF_CFG_188HZ		0x01
+#define BITS_DLPF_CFG_98HZ		0x02
+#define BITS_DLPF_CFG_42HZ		0x03
+#define BITS_DLPF_CFG_20HZ		0x04
+#define BITS_DLPF_CFG_10HZ		0x05
+#define BITS_DLPF_CFG_5HZ		0x06
+#define BITS_DLPF_CFG_2100HZ_NOLPF	0x07
+#define BITS_DLPF_CFG_MASK		0x07
+#define BIT_INT_ANYRD_2CLEAR		0x10
+#define BIT_RAW_RDY_EN			0x01
+#define BIT_I2C_IF_DIS			0x10
+#define BIT_INT_STATUS_DATA		0x01
+
+// Product ID Description for MPU6000
+// high 4 bits 	low 4 bits
+// Product Name	Product Revision
+#define MPU6000ES_REV_C4		0x14
+#define MPU6000ES_REV_C5		0x15
+#define MPU6000ES_REV_D6		0x16
+#define MPU6000ES_REV_D7		0x17
+#define MPU6000ES_REV_D8		0x18
+#define MPU6000_REV_C4			0x54
+#define MPU6000_REV_C5			0x55
+#define MPU6000_REV_D6			0x56
+#define MPU6000_REV_D7			0x57
+#define MPU6000_REV_D8			0x58
+#define MPU6000_REV_D9			0x59
+#define MPU6000_REV_D10			0x5A
+
+
+class MPU6000_gyro;
+
+class MPU6000 : public device::SPI
+{
+public:
+	MPU6000(int bus, spi_dev_e device);
+	~MPU6000();
+
+	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);
+
+	virtual int		open_first(struct file *filp);
+	virtual int		close_last(struct file *filp);
+
+	/**
+	 * Diagnostics - print some basic information about the driver.
+	 */
+	void			print_info();
+
+protected:
+	virtual int		probe();
+
+	friend class MPU6000_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:
+	MPU6000_gyro		*_gyro;
+	uint8_t			_product;	/** product code */
+
+	struct hrt_call		_call;
+	unsigned		_call_interval;
+
+	struct accel_report	_accel_report;
+	struct accel_scale	_accel_scale;
+	float			_accel_range_scale;
+	int			_accel_topic;
+
+	struct gyro_report	_gyro_report;
+	struct gyro_scale	_gyro_scale;
+	float			_gyro_range_scale;
+	int			_gyro_topic;
+
+	unsigned		_reads;
+	perf_counter_t		_sample_perf;
+
+	/**
+	 * Start automatic measurement.
+	 */
+	void			start();
+
+	/**
+	 * Stop automatic measurement.
+	 */
+	void			stop();
+
+	/**
+	 * Static trampoline from the hrt_call context; because we don't have a
+	 * generic hrt wrapper yet.
+	 *
+	 * Called by the HRT in interrupt context at the specified rate if
+	 * automatic polling is enabled.
+	 *
+	 * @param arg		Instance pointer for the driver that is polling.
+	 */
+	static void		measure_trampoline(void *arg);
+
+	/**
+	 * Fetch measurements from the sensor and update the report ring.
+	 */
+	void			measure();
+
+	/**
+	 * Read a register from the MPU6000
+	 *
+	 * @param		The register to read.
+	 * @return		The value that was read.
+	 */
+	uint8_t			read_reg(unsigned reg);
+	uint16_t		read_reg16(unsigned reg);
+
+	/**
+	 * Write a register in the MPU6000
+	 *
+	 * @param reg		The register to write.
+	 * @param value		The new value to write.
+	 */
+	void			write_reg(unsigned reg, uint8_t value);
+
+	/**
+	 * Modify a register in the MPU6000
+	 *
+	 * Bits are cleared before bits are set.
+	 *
+	 * @param reg		The register to modify.
+	 * @param clearbits	Bits in the register to clear.
+	 * @param setbits	Bits in the register to set.
+	 */
+	void			modify_reg(unsigned reg, uint8_t clearbits, uint8_t setbits);
+
+	/**
+	 * Set the MPU6000 measurement range.
+	 *
+	 * @param max_g		The maximum G value the range must support.
+	 * @return		OK if the value can be supported, -ERANGE otherwise.
+	 */
+	int			set_range(unsigned max_g);
+
+	/**
+	 * Swap a 16-bit value read from the MPU6000 to native byte order.
+	 */
+	uint16_t		swap16(uint16_t val) { return (val >> 8) | (val << 8);	}
+
+};
+
+/**
+ * Helper class implementing the gyro driver node.
+ */
+class MPU6000_gyro : public device::CDev
+{
+public:
+	MPU6000_gyro(MPU6000 *parent);
+	~MPU6000_gyro();
+
+	virtual ssize_t		read(struct file *filp, char *buffer, size_t buflen);
+	virtual int		ioctl(struct file *filp, int cmd, unsigned long arg);
+
+protected:
+	friend class MPU6000;
+
+	void			parent_poll_notify();
+private:
+	MPU6000			*_parent;
+};
+
+/** driver 'main' command */
+extern "C" { __EXPORT int mpu6000_main(int argc, char *argv[]); }
+
+MPU6000::MPU6000(int bus, spi_dev_e device) :
+	SPI("MPU6000", ACCEL_DEVICE_PATH, bus, device, SPIDEV_MODE3, 10000000),
+	_gyro(new MPU6000_gyro(this)),
+	_product(0),
+	_call_interval(0),
+	_accel_range_scale(1.0f),
+	_accel_topic(-1),
+	_gyro_range_scale(1.0f),
+	_gyro_topic(-1),
+	_reads(0),
+	_sample_perf(perf_alloc(PC_ELAPSED, "mpu6000_read"))
+{
+	// enable debug() calls
+	_debug_enabled = true;
+
+	// default accel scale factors
+	_accel_scale.x_offset = 0;
+	_accel_scale.x_scale  = 1.0f;
+	_accel_scale.y_offset = 0;
+	_accel_scale.y_scale  = 1.0f;
+	_accel_scale.z_offset = 0;
+	_accel_scale.z_scale  = 1.0f;
+
+	// default gyro scale factors
+	_gyro_scale.x_offset = 0;
+	_gyro_scale.x_scale  = 1.0f;
+	_gyro_scale.y_offset = 0;
+	_gyro_scale.y_scale  = 1.0f;
+	_gyro_scale.z_offset = 0;
+	_gyro_scale.z_scale  = 1.0f;
+
+	memset(&_accel_report, 0, sizeof(_accel_report));
+	memset(&_gyro_report, 0, sizeof(_gyro_report));
+}
+
+MPU6000::~MPU6000()
+{
+	/* make sure we are truly inactive */
+	stop();
+
+	/* delete the gyro subdriver */
+	delete _gyro;
+
+	/* delete the perf counter */
+	perf_free(_sample_perf);
+}
+
+int
+MPU6000::init()
+{
+	int ret;
+
+	/* do SPI init (and probe) first */
+	ret = SPI::init();
+
+	/* if probe/setup failed, bail now */
+	if (ret != OK) {
+		debug("SPI setup failed");
+		return ret;
+	}
+
+	/* advertise sensor topics */
+	_accel_topic = orb_advertise(ORB_ID(sensor_accel), &_accel_report);
+	_gyro_topic = orb_advertise(ORB_ID(sensor_gyro), &_gyro_report);
+
+	// Chip reset
+	write_reg(MPUREG_PWR_MGMT_1, BIT_H_RESET);
+	up_udelay(10000);
+
+	// Wake up device and select GyroZ clock (better performance)
+	write_reg(MPUREG_PWR_MGMT_1, MPU_CLK_SEL_PLLGYROZ);
+	up_udelay(1000);
+
+	// Disable I2C bus (recommended on datasheet)
+	write_reg(MPUREG_USER_CTRL, BIT_I2C_IF_DIS);
+	up_udelay(1000);
+
+	// SAMPLE RATE
+	write_reg(MPUREG_SMPLRT_DIV, 0x04);     // Sample rate = 200Hz    Fsample= 1Khz/(4+1) = 200Hz
+	usleep(1000);
+
+	// FS & DLPF   FS=2000¼/s, DLPF = 98Hz (low pass filter)
+	write_reg(MPUREG_CONFIG, BITS_DLPF_CFG_98HZ);
+	usleep(1000);
+	write_reg(MPUREG_GYRO_CONFIG,BITS_FS_2000DPS);  // Gyro scale 2000¼/s
+	usleep(1000);
+
+	// product-specific scaling
+	switch (_product) {
+	case MPU6000ES_REV_C4:
+	case MPU6000ES_REV_C5:
+	case MPU6000_REV_C4:
+	case MPU6000_REV_C5:
+		// Accel scale 8g (4096 LSB/g)
+		// Rev C has different scaling than rev D
+		write_reg(MPUREG_ACCEL_CONFIG, 1 << 3);
+		break;
+
+	case MPU6000ES_REV_D6:
+	case MPU6000ES_REV_D7:
+	case MPU6000ES_REV_D8:
+	case MPU6000_REV_D6:
+	case MPU6000_REV_D7:
+	case MPU6000_REV_D8:
+	case MPU6000_REV_D9:
+	case MPU6000_REV_D10:
+		// Accel scale 8g (4096 LSB/g)
+		write_reg(MPUREG_ACCEL_CONFIG,2<<3);
+		break;
+	}
+	usleep(1000);
+
+	// INT CFG => Interrupt on Data Ready
+	write_reg(MPUREG_INT_ENABLE,BIT_RAW_RDY_EN);         // INT: Raw data ready
+	usleep(1000);
+	write_reg(MPUREG_INT_PIN_CFG,BIT_INT_ANYRD_2CLEAR);  // INT: Clear on any read
+	usleep(1000);
+
+	// Oscillator set
+	// write_reg(MPUREG_PWR_MGMT_1,MPU_CLK_SEL_PLLGYROZ);
+	usleep(1000);
+
+
+	return ret;
+}
+
+int
+MPU6000::open_first(struct file *filp)
+{
+	/* reset to manual-poll mode */
+	_call_interval = 0;
+
+	/* XXX set default sampling/acquisition parameters */
+
+	return OK;
+}
+
+int
+MPU6000::close_last(struct file *filp)
+{
+	/* stop measurement */
+	stop();
+
+	return OK;
+}
+
+int
+MPU6000::probe()
+{
+
+	/* look for a product ID we recognise */
+	_product = read_reg(MPUREG_PRODUCT_ID);
+
+	// verify product revision
+	switch (_product) {
+	case MPU6000ES_REV_C4:
+	case MPU6000ES_REV_C5:
+	case MPU6000_REV_C4:
+	case MPU6000_REV_C5:
+	case MPU6000ES_REV_D6:
+	case MPU6000ES_REV_D7:
+	case MPU6000ES_REV_D8:
+	case MPU6000_REV_D6:
+	case MPU6000_REV_D7:
+	case MPU6000_REV_D8:
+	case MPU6000_REV_D9:
+	case MPU6000_REV_D10:
+		log("ID 0x%02x", _product);
+		return OK;
+	}
+
+	debug("unexpected ID 0x%02x", _product);
+	return -EIO;
+}
+
+ssize_t
+MPU6000::read(struct file *filp, char *buffer, size_t buflen)
+{
+	int ret = 0;
+
+	/* buffer must be large enough */
+	if (buflen < sizeof(_accel_report))
+		return -ENOSPC;
+
+	/* if automatic measurement is not enabled */
+	if (_call_interval == 0)
+		measure();
+
+	/* copy out the latest report */
+	memcpy(buffer, &_accel_report, sizeof(_accel_report));
+	ret = sizeof(_accel_report);
+
+	return ret;
+}
+
+ssize_t
+MPU6000::gyro_read(struct file *filp, char *buffer, size_t buflen)
+{
+	int ret = 0;
+
+	/* buffer must be large enough */
+	if (buflen < sizeof(_gyro_report))
+		return -ENOSPC;
+
+	/* if automatic measurement is not enabled */
+	if (_call_interval == 0)
+		measure();
+
+	/* copy out the latest report */
+	memcpy(buffer, &_gyro_report, sizeof(_gyro_report));
+	ret = sizeof(_gyro_report);
+
+	return ret;
+}
+
+int
+MPU6000::ioctl(struct file *filp, int cmd, unsigned long arg)
+{
+	switch (cmd) {
+
+	case ACCELIOCSPOLLRATE: {
+			switch (arg) {
+
+				/* switching to manual polling */
+			case ACC_POLLRATE_MANUAL:
+				stop();
+				_call_interval = 0;
+				return OK;
+
+				/* external signalling not supported */
+			case ACC_POLLRATE_EXTERNAL:
+
+				/* zero would be bad */
+			case 0:
+				return -EINVAL;
+
+				/* adjust to a legal polling interval in Hz */
+			default: {
+					/* do we need to start internal polling? */
+					bool want_start = (_call_interval == 0);
+
+					/* convert hz to hrt interval via microseconds */
+					unsigned ticks = 1000000 / arg;
+
+					/* check against maximum sane rate */
+					if (ticks < 1000)
+						return -EINVAL;
+
+					/* update interval for next measurement */
+					/* XXX this is a bit shady, but no other way to adjust... */
+					_call.period = _call_interval;
+
+					/* if we need to start the poll state machine, do it */
+					if (want_start)
+						start();
+
+					return OK;
+				}
+			}
+		}
+
+	case ACCELIOCSQUEUEDEPTH:
+		/* XXX not implemented */
+		return -EINVAL;
+
+	case ACCELIOCSLOWPASS:
+		/* XXX not implemented */
+		return -EINVAL;
+
+	case ACCELIORANGE:
+		/* XXX not implemented really */
+		return set_range(arg);
+
+	case ACCELIOCSSAMPLERATE:	/* sensor sample rate is not (really) adjustable */
+	case ACCELIOCSREPORTFORMAT:	/* no alternate report formats */
+		return -EINVAL;
+
+	default:
+		/* give it to the superclass */
+		return SPI::ioctl(filp, cmd, arg);
+	}
+}
+
+int
+MPU6000::gyro_ioctl(struct file *filp, int cmd, unsigned long arg)
+{
+	switch (cmd) {
+
+	case GYROIOCSPOLLRATE:
+		/* gyro and accel poll rates are shared */
+		return ioctl(filp, ACCELIOCSPOLLRATE, arg);
+
+	case GYROIOCSQUEUEDEPTH:
+		/* XXX not implemented */
+		return -EINVAL;
+
+	case GYROIOCSLOWPASS:
+		/* XXX not implemented */
+		return -EINVAL;
+
+	case GYROIOCSSCALE:
+		/* XXX not implemented really */
+		return set_range(arg);
+
+	case GYROIOCSSAMPLERATE:	/* sensor sample rate is not (really) adjustable */
+	case GYROIOCSREPORTFORMAT:	/* no alternate report formats */
+		return -EINVAL;
+
+	default:
+		/* give it to the superclass */
+		return SPI::ioctl(filp, cmd, arg);
+	}
+}
+
+uint8_t
+MPU6000::read_reg(unsigned reg)
+{
+	uint8_t cmd[2];
+
+	cmd[0] = reg | DIR_READ;
+
+	transfer(cmd, cmd, sizeof(cmd));
+
+	return cmd[1];
+}
+
+uint16_t
+MPU6000::read_reg16(unsigned reg)
+{
+	uint8_t cmd[3];
+
+	cmd[0] = reg | DIR_READ;
+
+	transfer(cmd, cmd, sizeof(cmd));
+
+	return (uint16_t)(cmd[1] << 8) | cmd[2];
+}
+
+void
+MPU6000::write_reg(unsigned reg, uint8_t value)
+{
+	uint8_t	cmd[2];
+
+	cmd[0] = reg | DIR_WRITE;
+	cmd[1] = value;
+
+	transfer(cmd, nullptr, sizeof(cmd));
+}
+
+void
+MPU6000::modify_reg(unsigned reg, uint8_t clearbits, uint8_t setbits)
+{
+	uint8_t	val;
+
+	val = read_reg(reg);
+	val &= ~clearbits;
+	val |= setbits;
+	write_reg(reg, val);
+}
+
+int
+MPU6000::set_range(unsigned max_g)
+{
+#if 0
+	uint8_t rangebits;
+	float rangescale;
+
+	if (max_g > 16) {
+		return -ERANGE;
+
+	} else if (max_g > 8) {		/* 16G */
+		rangebits = OFFSET_LSB1_RANGE_16G;
+		rangescale = 1.98;
+
+	} else if (max_g > 4) {		/* 8G */
+		rangebits = OFFSET_LSB1_RANGE_8G;
+		rangescale = 0.99;
+
+	} else if (max_g > 3) {		/* 4G */
+		rangebits = OFFSET_LSB1_RANGE_4G;
+		rangescale = 0.5;
+
+	} else if (max_g > 2) {		/* 3G */
+		rangebits = OFFSET_LSB1_RANGE_3G;
+		rangescale = 0.38;
+
+	} else if (max_g > 1) {		/* 2G */
+		rangebits = OFFSET_LSB1_RANGE_2G;
+		rangescale = 0.25;
+
+	} else {			/* 1G */
+		rangebits = OFFSET_LSB1_RANGE_1G;
+		rangescale = 0.13;
+	}
+
+	/* adjust sensor configuration */
+	modify_reg(ADDR_OFFSET_LSB1, OFFSET_LSB1_RANGE_MASK, rangebits);
+	_range_scale = rangescale;
+#endif
+	return OK;
+}
+
+void
+MPU6000::start()
+{
+	/* make sure we are stopped first */
+	stop();
+
+	/* start polling at the specified rate */
+	hrt_call_every(&_call, 1000, _call_interval, (hrt_callout)&MPU6000::measure_trampoline, this);
+}
+
+void
+MPU6000::stop()
+{
+	hrt_cancel(&_call);
+}
+
+void
+MPU6000::measure_trampoline(void *arg)
+{
+	MPU6000 *dev = (MPU6000 *)arg;
+
+	/* make another measurement */
+	dev->measure();
+}
+
+void
+MPU6000::measure()
+{
+#pragma pack(push, 1)
+	/**
+	 * Report conversation within the MPU6000, including command byte and
+	 * interrupt status.
+	 */
+	struct Report {
+		uint8_t		cmd;
+		uint8_t		status;
+		uint16_t	accel_x;
+		uint16_t	accel_y;
+		uint16_t	accel_z;
+		uint16_t	temp;
+		uint16_t	gyro_x;
+		uint16_t	gyro_y;
+		uint16_t	gyro_z;
+	} report;
+#pragma pack(pop)
+
+	/* start measuring */
+	perf_begin(_sample_perf);
+
+	/*
+	 * Fetch the full set of measurements from the MPU6000 in one pass.
+	 */
+	report.cmd = DIR_READ | MPUREG_INT_STATUS;
+	transfer((uint8_t *)&report, (uint8_t *)&report, sizeof(report));
+
+	/*
+	 * Adjust and scale results to mg.
+	 */
+	_gyro_report.timestamp = _accel_report.timestamp = hrt_absolute_time();
+
+	_accel_report.x = report.accel_x * _accel_range_scale;
+	_accel_report.y = report.accel_y * _accel_range_scale;
+	_accel_report.z = report.accel_z * _accel_range_scale;
+
+	_gyro_report.x = report.gyro_x * _gyro_range_scale;
+	_gyro_report.y = report.gyro_y * _gyro_range_scale;
+	_gyro_report.z = report.gyro_z * _gyro_range_scale;
+
+	/* notify anyone waiting for data */
+	poll_notify(POLLIN);
+	_gyro->parent_poll_notify();
+
+	/* and publish for subscribers */
+	orb_publish(ORB_ID(sensor_accel), _accel_topic, &_accel_report);
+	orb_publish(ORB_ID(sensor_gyro), _gyro_topic, &_gyro_report);
+
+	/* stop measuring */
+	perf_end(_sample_perf);
+}
+
+void
+MPU6000::print_info()
+{
+	printf("reads:          %u\n", _reads);
+}
+
+MPU6000_gyro::MPU6000_gyro(MPU6000 *parent) :
+	CDev("MPU6000_gyro", GYRO_DEVICE_PATH),
+	_parent(parent)
+{
+}
+
+MPU6000_gyro::~MPU6000_gyro()
+{
+}
+
+void
+MPU6000_gyro::parent_poll_notify()
+{
+	poll_notify(POLLIN);
+}
+
+ssize_t
+MPU6000_gyro::read(struct file *filp, char *buffer, size_t buflen)
+{
+	return _parent->gyro_read(filp, buffer, buflen);
+}
+
+int
+MPU6000_gyro::ioctl(struct file *filp, int cmd, unsigned long arg)
+{
+	return _parent->gyro_ioctl(filp, cmd, arg);
+}
+
+/**
+ * Local functions in support of the shell command.
+ */
+namespace
+{
+
+MPU6000	*g_dev;
+
+/*
+ * XXX this should just be part of the generic sensors test...
+ */
+
+int
+test()
+{
+	int fd = -1;
+	struct accel_report report;
+	ssize_t sz;
+	const char *reason = "test OK";
+
+	do {
+
+		/* get the driver */
+		fd = open(ACCEL_DEVICE_PATH, O_RDONLY);
+
+		if (fd < 0) {
+			reason = "can't open driver";
+			break;
+		}
+
+		/* do a simple demand read */
+		sz = read(fd, &report, sizeof(report));
+
+		if (sz != sizeof(report)) {
+			reason = "immediate read failed";
+			break;
+		}
+
+		printf("single read\n");
+		fflush(stdout);
+		printf("time:        %lld\n", report.timestamp);
+		printf("x:           %f\n", report.x);
+		printf("y:           %f\n", report.y);
+		printf("z:           %f\n", report.z);
+
+	} while (0);
+
+	printf("MPU6000: %s\n", reason);
+
+	return OK;
+}
+
+int
+info()
+{
+	if (g_dev == nullptr) {
+		fprintf(stderr, "MPU6000: driver not running\n");
+		return -ENOENT;
+	}
+
+	printf("state @ %p\n", g_dev);
+	g_dev->print_info();
+
+	return OK;
+}
+
+
+} // namespace
+
+int
+mpu6000_main(int argc, char *argv[])
+{
+	/*
+	 * Start/load the driver.
+	 *
+	 * XXX it would be nice to have a wrapper for this...
+	 */
+	if (!strcmp(argv[1], "start")) {
+
+		if (g_dev != nullptr) {
+			fprintf(stderr, "MPU6000: already loaded\n");
+			return -EBUSY;
+		}
+
+		/* create the driver */
+		g_dev = new MPU6000(1 /* XXX magic number */, (spi_dev_e)PX4_SPIDEV_MPU);
+
+		if (g_dev == nullptr) {
+			fprintf(stderr, "MPU6000: driver alloc failed\n");
+			return -ENOMEM;
+		}
+
+		if (OK != g_dev->init()) {
+			fprintf(stderr, "MPU6000: driver init failed\n");
+			usleep(100000);
+			delete g_dev;
+			g_dev = nullptr;
+			return -EIO;
+		}
+		return OK;
+	}
+
+	/*
+	 * Test the driver/device.
+	 */
+	if (!strcmp(argv[1], "test"))
+		return test();
+
+	/*
+	 * Print driver information.
+	 */
+	if (!strcmp(argv[1], "info"))
+		return info();
+
+	fprintf(stderr, "unrecognised command, try 'start', 'test' or 'info'\n");
+	return -EINVAL;
+}