driver work in progress

2 files changed, 864 insertions, 0 deletions

diff --git a/apps/drivers/l3gd20/Makefile b/apps/drivers/l3gd20/Makefile
new file mode 100644
index 000000000..98e2d57c5
--- /dev/null
+++ b/apps/drivers/l3gd20/Makefile
@@ -0,0 +1,42 @@
+############################################################################
+#
+#   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.
+#
+############################################################################
+
+#
+# Makefile to build the L3GD20 driver.
+#
+
+APPNAME		 = l3gd20
+PRIORITY	 = SCHED_PRIORITY_DEFAULT
+STACKSIZE	 = 2048
+
+include $(APPDIR)/mk/app.mk
diff --git a/apps/drivers/l3gd20/l3gd20.cpp b/apps/drivers/l3gd20/l3gd20.cpp
new file mode 100644
index 000000000..747abd82e
--- /dev/null
+++ b/apps/drivers/l3gd20/l3gd20.cpp
@@ -0,0 +1,822 @@
+/****************************************************************************
+ *
+ *   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 Driver for the ST L3GD20 MEMS gyro connected via SPI.
+ */
+
+#include <nuttx/config.h>
+
+#include <device/spi.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 <nuttx/arch.h>
+#include <nuttx/clock.h>
+
+#include <arch/board/up_hrt.h>
+
+#include <drivers/drv_gyro.h>
+
+extern "C" { __EXPORT int l3gd20_main(int argc, char *argv[]); }
+
+class L3GD20 : public device::SPI
+{
+public:
+	L3GD20(int bus, spi_dev_e device);
+	~L3GD20();
+
+	virtual int		init();
+
+	virtual ssize_t		read(struct file *filp, char *buffer, size_t buflen);
+	virtual int		ioctl(struct file *filp, int cmd, unsigned long arg);
+
+	/**
+	 * Diagnostics - print some basic information about the driver.
+	 */
+	void			print_info();
+
+protected:
+	virtual int		probe();
+
+private:
+
+	struct hrt_call		_call;
+	unsigned		_call_interval;
+
+	unsigned		_num_reports;
+	volatile unsigned	_next_report;
+	volatile unsigned	_oldest_report;
+	struct gyro_report	*_reports;
+
+	struct gyro_scale	_scale;
+	float			_range_scale;
+
+	unsigned		_reads;
+
+	unsigned		_rate;
+	unsigned		_range;
+
+	/**
+	 * 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 L3GD20
+	 *
+	 * @param		The register to read.
+	 * @return		The value that was read.
+	 */
+	uint8_t			read_reg(unsigned reg);
+
+	/**
+	 * Write a register in the L3GD20
+	 *
+	 * @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 L3GD20
+	 *
+	 * 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 L3GD20 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);
+
+	/**
+	 * Set the L3GD20 lowpass filter.
+	 *
+	 * @param frequency	Set the lowpass filter cutoff frequency to no less than
+	 *			this frequency.
+	 * @return		OK if the value can be supported.
+	 */
+	int			set_bandwidth(unsigned frequency);
+};
+
+/* helper macro for handling report buffer indices */
+#define INCREMENT(_x, _lim)	do { _x++; if (_x >= _lim) _x = 0; } while(0)
+
+#define DIR_READ				(1<<7)
+#define DIR_WRITE				(0<<7)
+#define ADDR_INCREMENT				(1<<6)
+
+#define ADDR_WHO_AM_I				0x0F
+#define WHO_I_AM				0xD4
+#define ADDR_CTRL_REG1				0x20
+#define ADDR_CTRL_REG2				0x21
+#define ADDR_CTRL_REG3				0x22
+#define ADDR_CTRL_REG4				0x23
+#define ADDR_CTRL_REG5				0x24
+#define ADDR_REFERENCE				0x25
+#define ADDR_OUT_TEMP				0x26
+#define ADDR_STATUS_REG				0x27
+#define ADDR_OUT_X_L				0x28
+#define ADDR_OUT_X_H				0x29
+#define ADDR_OUT_Y_L				0x2A
+#define ADDR_OUT_Y_H				0x2B
+#define ADDR_OUT_Z_L				0x2C
+#define ADDR_OUT_Z_H				0x2D
+#define ADDR_FIFO_CTRL_REG			0x2E
+#define ADDR_FIFO_SRC_REG			0x2F
+#define ADDR_INT1_CFG				0x30
+#define ADDR_INT1_SRC				0x31
+#define ADDR_INT1_TSH_XH			0x32
+#define ADDR_INT1_TSH_XL			0x33
+#define ADDR_INT1_TSH_YH			0x34
+#define ADDR_INT1_TSH_YL			0x35
+#define ADDR_INT1_TSH_ZH			0x36
+#define ADDR_INT1_TSH_ZL			0x37
+#define ADDR_INT1_DURATION			0x38
+
+#define REG1_RATE_LP_MASK			0xF0 /* Mask to guard partial register update */
+#define REG4_RANGE_MASK				0x30 /* Mask to guard partial register update */
+
+/* Internal configuration values */
+#define REG1_POWER_NORMAL			(1<<3)
+#define REG1_Z_ENABLE				(1<<2)
+#define REG1_Y_ENABLE				(1<<1)
+#define REG1_X_ENABLE				(1<<0)
+
+#define REG4_BDU				(1<<7)
+#define REG4_BLE				(1<<6)
+//#define REG4_SPI_3WIRE			(1<<0)
+
+#define REG5_FIFO_ENABLE			(1<<6)
+#define REG5_REBOOT_MEMORY			(1<<7)
+
+#define STATUS_ZYXOR				(1<<7)
+#define STATUS_ZOR				(1<<6)
+#define STATUS_YOR				(1<<5)
+#define STATUS_XOR				(1<<4)
+#define STATUS_ZYXDA				(1<<3)
+#define STATUS_ZDA				(1<<2)
+#define STATUS_YDA				(1<<1)
+#define STATUS_XDA				(1<<0)
+
+#define FIFO_CTRL_BYPASS_MODE			(0<<5)
+#define FIFO_CTRL_FIFO_MODE			(1<<5)
+#define FIFO_CTRL_STREAM_MODE			(1<<6)
+#define FIFO_CTRL_STREAM_TO_FIFO_MODE		(3<<5)
+#define FIFO_CTRL_BYPASS_TO_STREAM_MODE		(1<<7)
+
+#define L3GD20_RANGE_250DPS			(0<<4)
+#define L3GD20_RANGE_500DPS			(1<<4)
+#define L3GD20_RANGE_2000DPS			(3<<4)
+
+#define L3GD20_RATE_95HZ			((0<<6) | (0<<4))
+#define L3GD20_RATE_190HZ			((1<<6) | (0<<4))
+#define L3GD20_RATE_380HZ			((2<<6) | (1<<4))
+#define L3GD20_RATE_760HZ			((3<<6) | (2<<4))
+
+/*
+ * Driver 'main' command.
+ */
+extern "C" { int l3gd20_main(int argc, char *argv[]); }
+
+
+L3GD20::L3GD20(int bus, spi_dev_e device) :
+	SPI("L3GD20", GYRO_DEVICE_PATH, bus, device, SPIDEV_MODE3, 8000000),
+	_num_reports(0),
+	_next_report(0),
+	_oldest_report(0),
+	_reports(nullptr),
+	_reads(0),
+	_rate(L3GD20_RATE_760HZ),
+	_range(L3GD20_RANGE_2000DPS)
+{
+	// enable debug() calls
+	_debug_enabled = true;
+
+	// default scale factors XXX
+	_scale.x_offset = 0;
+	_scale.x_scale  = 1.0f;
+	_scale.y_offset = 0;
+	_scale.y_scale  = 1.0f;
+	_scale.z_offset = 0;
+	_scale.z_scale  = 1.0f;
+}
+
+L3GD20::~L3GD20()
+{
+	/* make sure we are truly inactive */
+	stop();
+
+	/* free any existing reports */
+	if (_reports != nullptr)
+		delete[] _reports;
+}
+
+int
+L3GD20::init()
+{
+	int ret = ERROR;
+
+	/* do SPI init (and probe) first */
+	if (SPI::init() != OK)
+		goto out;
+
+	/* allocate basic report buffers */
+	_num_reports = 2;
+	_oldest_report = _next_report = 0;
+	_reports = new struct gyro_report[_num_reports];
+	if (_reports == nullptr)
+		goto out;
+
+	/* set default configuration */
+	write_reg(ADDR_CTRL_REG1, REG1_POWER_NORMAL | REG1_Z_ENABLE | REG1_Y_ENABLE | REG1_X_ENABLE);
+	write_reg(ADDR_CTRL_REG2, 0);		/* disable high-pass filters */
+	write_reg(ADDR_CTRL_REG3, 0);		/* no interrupts - we don't use them */
+	write_reg(ADDR_CTRL_REG4, 0x10);
+	write_reg(ADDR_CTRL_REG5, 0);
+		
+	write_reg(ADDR_CTRL_REG5, REG5_FIFO_ENABLE);	  /* disable wake-on-interrupt */
+	write_reg(ADDR_FIFO_CTRL_REG, FIFO_CTRL_STREAM_MODE); /* Enable FIFO, old data is overwritten */
+
+	if ((set_range(L3GD20_RANGE_500DPS) != 0) ||
+	    (set_rate(L3GD20_RATE_760HZ_LP_100HZ) != 0))
+		goto out;
+
+	ret = OK;
+out:
+	return ret;
+}
+
+int
+L3GD20::probe()
+{
+	/* read dummy value to void to clear SPI statemachine on sensor */
+	(void)read_reg(ADDR_WHO_AM_I);
+
+	/* verify that the device is attached and functioning */
+	if (read_reg(ADDR_WHO_AM_I) == WHO_I_AM)
+		return OK;
+
+	return -EIO;
+}
+
+ssize_t
+L3GD20::read(struct file *filp, char *buffer, size_t buflen)
+{
+	unsigned count = buflen / sizeof(struct gyro_report);
+	int ret = 0;
+
+	/* buffer must be large enough */
+	if (count < 1)
+		return -ENOSPC;
+
+	/* if automatic measurement is enabled */
+	if (_call_interval > 0) {
+
+		/*
+		 * While there is space in the caller's buffer, and reports, copy them.
+		 * Note that we may be pre-empted by the measurement code while we are doing this;
+		 * we are careful to avoid racing with it.
+		 */
+		while (count--) {
+			if (_oldest_report != _next_report) {
+				memcpy(buffer, _reports + _oldest_report, sizeof(*_reports));
+				ret += sizeof(_reports[0]);
+				INCREMENT(_oldest_report, _num_reports);
+			}
+		}
+
+		_reads++;
+
+		/* if there was no data, warn the caller */
+		return ret ? ret : -EAGAIN;
+	}
+
+	/* manual measurement */
+	_oldest_report = _next_report = 0;
+	measure();
+
+	/* measurement will have generated a report, copy it out */
+	memcpy(buffer, _reports, sizeof(*_reports));
+	ret = sizeof(*_reports);
+
+	return ret;
+}
+
+int
+L3GD20::ioctl(struct file *filp, int cmd, unsigned long arg)
+{
+	switch (cmd) {
+
+	case SENSORIOCSPOLLRATE: {
+			switch (arg) {
+
+				/* switching to manual polling */
+			case SENSOR_POLLRATE_MANUAL:
+				stop();
+				_call_interval = 0;
+				return OK;
+
+				/* external signalling not supported */
+			case SENSOR_POLLRATE_EXTERNAL:
+
+				/* zero would be bad */
+			case 0:
+				return -EINVAL;
+
+				/* set default/max polling rate */
+			case SENSOR_POLLRATE_MAX:
+			case SENSOR_POLLRATE_DEFAULT:
+				/* XXX 500Hz is just a wild guess */
+				return ioctl(filp, SENSORIOCSPOLLRATE, 500);
+
+				/* 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 SENSORIOCGPOLLRATE:
+		if (_call_interval == 0)
+			return SENSOR_POLLRATE_MANUAL;
+		return 1000000 / _call_interval;
+
+	case SENSORIOCSQUEUEDEPTH: {
+			/* account for sentinel in the ring */
+			arg++;
+
+			/* lower bound is mandatory, upper bound is a sanity check */
+			if ((arg < 2) || (arg > 100))
+				return -EINVAL;
+
+			/* allocate new buffer */
+			struct gyro_report *buf = new struct gyro_report[arg];
+
+			if (nullptr == buf)
+				return -ENOMEM;
+
+			/* reset the measurement state machine with the new buffer, free the old */
+			stop();
+			delete[] _reports;
+			_num_reports = arg;
+			_reports = buf;
+			start();
+
+			return OK;
+		}
+
+	case SENSORIOCGQUEUEDEPTH:
+		return _num_reports -1;
+
+	case SENSORIOCRESET:
+		/* XXX implement */
+		return -EINVAL;
+
+	case GYROIOCSSAMPLERATE:
+	case GYROIOCGSAMPLERATE:
+		/* XXX not implemented */
+		return -EINVAL;
+
+	case GYROIOCSLOWPASS:
+	case GYROIOCGLOWPASS:
+		/* XXX not implemented */
+		return -EINVAL;
+
+	case GYROIOCSSCALE:
+	case GYROIOCGSCALE:
+		/* XXX not implemented */
+		return -EINVAL;
+
+	case GYROIOCSRANGE:
+	case GYROIOCGRANGE:
+		/* XXX not implemented */
+		// XXX change these two values on set:
+		// _gyro_range_scale = xx
+		// _gyro_range_m_s2 = xx
+		return -EINVAL;
+
+	default:
+		/* give it to the superclass */
+		return SPI::ioctl(filp, cmd, arg);
+}
+
+uint8_t
+L3GD20::read_reg(unsigned reg)
+{
+	uint8_t cmd[2];
+
+	cmd[0] = reg | DIR_READ;
+
+	transfer(cmd, cmd, sizeof(cmd));
+
+	return cmd[1];
+}
+
+void
+L3GD20::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
+L3GD20::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
+L3GD20::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;
+}
+
+int
+L3GD20::set_bandwidth(unsigned frequency)
+{
+#if 0
+	uint8_t	bwbits;
+
+	if (frequency > 1200) {
+		return -ERANGE;
+
+	} else if (frequency > 600) {
+		bwbits = BW_TCS_BW_1200HZ;
+
+	} else if (frequency > 300) {
+		bwbits = BW_TCS_BW_600HZ;
+
+	} else if (frequency > 150) {
+		bwbits = BW_TCS_BW_300HZ;
+
+	} else if (frequency > 75) {
+		bwbits = BW_TCS_BW_150HZ;
+
+	} else if (frequency > 40) {
+		bwbits = BW_TCS_BW_75HZ;
+
+	} else if (frequency > 20) {
+		bwbits = BW_TCS_BW_40HZ;
+
+	} else if (frequency > 10) {
+		bwbits = BW_TCS_BW_20HZ;
+
+	} else {
+		bwbits = BW_TCS_BW_10HZ;
+	}
+
+	/* adjust sensor configuration */
+	modify_reg(ADDR_BW_TCS, BW_TCS_BW_MASK, bwbits);
+#endif
+	return OK;
+}
+
+void
+L3GD20::start()
+{
+	/* make sure we are stopped first */
+	stop();
+
+	/* reset the report ring */
+	_oldest_report = _next_report = 0;
+
+	/* start polling at the specified rate */
+	hrt_call_every(&_call, 1000, _call_interval, (hrt_callout)&L3GD20::measure_trampoline, this);
+}
+
+void
+L3GD20::stop()
+{
+	hrt_cancel(&_call);
+}
+
+void
+L3GD20::measure_trampoline(void *arg)
+{
+	L3GD20 *dev = (L3GD20 *)arg;
+
+	/* make another measurement */
+	dev->measure();
+}
+
+void
+L3GD20::measure()
+{
+	/* status register and data as read back from the device */
+#pragma pack(push, 1)
+	struct {
+		uint8_t		cmd;
+		uint8_t		temp;
+		uint8_t		status;
+		int16_t		x;
+		int16_t		y;
+		int16_t		z;
+	} raw_report;
+#pragma pack(pop)
+
+	gyro_report		*report = &_reports[_next_report];
+
+	/* start the performance counter */
+	perf_begin(_sample_perf);
+
+	/* fetch data from the sensor */
+	report.cmd = ADDR_OUT_TEMP | DIR_READ | ADDR_INCREMENT;
+	transfer(&report, &report, sizeof(report));
+
+	/*
+	 * 1) Scale raw value to SI units using scaling from datasheet.
+	 * 2) Subtract static offset (in SI units)
+	 * 3) Scale the statically calibrated values with a linear
+	 *    dynamically obtained factor
+	 *
+	 * Note: the static sensor offset is the number the sensor outputs
+	 * 	 at a nominally 'zero' input. Therefore the offset has to
+	 * 	 be subtracted.
+	 *
+	 *	 Example: A gyro outputs a value of 74 at zero angular rate
+	 *	 	  the offset is 74 from the origin and subtracting
+	 *		  74 from all measurements centers them around zero.
+	 */
+	report->timestamp = hrt_absolute_time();
+	/* XXX adjust for sensor alignment to board here */
+	report->raw_x = raw_report.x;
+	report->raw_y = raw_report.y;
+	report->raw_z = raw_report.z;
+
+	report->x = ((raw_report.x * _range_scale) - _scale.x_offset) * _scale.x_scale;
+	report->y = ((raw_report.y * _range_scale) - _scale.y_offset) * _scale.y_scale;
+	report->z = ((raw_report.z * _range_scale) - _scale.z_offset) * _scale.z_scale;
+	report->scaling = _range_scale;
+	report->range_rad_s = _range_rad_s;
+
+	/* notify anyone waiting for data */
+	poll_notify(POLLIN);
+
+	/* publish for subscribers */
+	orb_publish(ORB_ID(sensor_gyro), _gyro_topic, &_gyro_report);
+
+	/* stop the perf counter */
+	perf_end(_sample_perf);
+}
+
+void
+L3GD20::print_info()
+{
+	printf("reads:          %u\n", _reads);
+	printf("report queue:   %u (%u/%u @ %p)\n",
+	       _num_reports, _oldest_report, _next_report, _reports);
+}
+
+/**
+ * Local functions in support of the shell command.
+ */
+namespace
+{
+
+L3GD20	*g_dev;
+
+/*
+ * XXX this should just be part of the generic sensors test...
+ */
+
+int
+test()
+{
+	int fd = -1;
+	struct gyro_report report;
+	ssize_t sz;
+	const char *reason = "test OK";
+
+	do {
+
+		/* get the driver */
+		fd = open(GYRO_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("L3GD20: %s\n", reason);
+
+	return OK;
+}
+
+int
+info()
+{
+	if (g_dev == nullptr) {
+		fprintf(stderr, "L3GD20: driver not running\n");
+		return -ENOENT;
+	}
+
+	printf("state @ %p\n", g_dev);
+	g_dev->print_info();
+
+	return OK;
+}
+
+
+} // namespace
+
+int
+l3gd20_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, "L3GD20: already loaded\n");
+			return -EBUSY;
+		}
+
+		/* create the driver */
+		g_dev = new L3GD20(CONFIG_L3GD20_SPI_BUS, (spi_dev_e)CONFIG_L3GD20_SPI_DEVICE);
+
+		if (g_dev == nullptr) {
+			fprintf(stderr, "L3GD20: driver alloc failed\n");
+			return -ENOMEM;
+		}
+
+		if (OK != g_dev->init()) {
+			fprintf(stderr, "L3GD20: driver init failed\n");
+			usleep(100000);
+			delete g_dev;
+			g_dev = nullptr;
+			return -EIO;
+		}
+
+		printf("L3GD20: driver started\n");
+		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;
+}