/****************************************************************************
*
* Copyright (C) 2013 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,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @file ets_airspeed.cpp
* @author Simon Wilks
*
* Driver for the Eagle Tree Airspeed V3 connected via I2C.
*/
#include <nuttx/config.h>
#include <drivers/device/i2c.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdbool.h>
#include <semaphore.h>
#include <string.h>
#include <fcntl.h>
#include <poll.h>
#include <errno.h>
#include <stdio.h>
#include <math.h>
#include <unistd.h>
#include <nuttx/arch.h>
#include <nuttx/wqueue.h>
#include <nuttx/clock.h>
#include <arch/board/board.h>
#include <systemlib/airspeed.h>
#include <systemlib/err.h>
#include <systemlib/param/param.h>
#include <systemlib/perf_counter.h>
#include <drivers/drv_airspeed.h>
#include <drivers/drv_hrt.h>
#include <uORB/uORB.h>
#include <uORB/topics/differential_pressure.h>
#include <uORB/topics/subsystem_info.h>
/* Default I2C bus */
#define PX4_I2C_BUS_DEFAULT PX4_I2C_BUS_EXPANSION
/* I2C bus address */
#define I2C_ADDRESS 0x75 /* 7-bit address. 8-bit address is 0xEA */
/* Register address */
#define READ_CMD 0x07 /* Read the data */
/**
* The Eagle Tree Airspeed V3 cannot provide accurate reading below speeds of 15km/h.
* You can set this value to 12 if you want a zero reading below 15km/h.
*/
#define MIN_ACCURATE_DIFF_PRES_PA 0
/* Measurement rate is 100Hz */
#define CONVERSION_INTERVAL (1000000 / 100) /* microseconds */
/* Oddly, ERROR is not defined for C++ */
#ifdef ERROR
# undef ERROR
#endif
static const int ERROR = -1;
#ifndef CONFIG_SCHED_WORKQUEUE
# error This requires CONFIG_SCHED_WORKQUEUE.
#endif
class ETSAirspeed : public device::I2C
{
public:
ETSAirspeed(int bus, int address = I2C_ADDRESS);
virtual ~ETSAirspeed();
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:
work_s _work;
unsigned _num_reports;
volatile unsigned _next_report;
volatile unsigned _oldest_report;
differential_pressure_s *_reports;
bool _sensor_ok;
int _measure_ticks;
bool _collect_phase;
float _diff_pres_offset;
orb_advert_t _airspeed_pub;
perf_counter_t _sample_perf;
perf_counter_t _comms_errors;
perf_counter_t _buffer_overflows;
/**
* Test whether the device supported by the driver is present at a
* specific address.
*
* @param address The I2C bus address to probe.
* @return True if the device is present.
*/
int probe_address(uint8_t address);
/**
* Initialise the automatic measurement state machine and start it.
*
* @note This function is called at open and error time. It might make sense
* to make it more aggressive about resetting the bus in case of errors.
*/
void start();
/**
* Stop the automatic measurement state machine.
*/
void stop();
/**
* Perform a poll cycle; collect from the previous measurement
* and start a new one.
*/
void cycle();
int measure();
int collect();
/**
* Static trampoline from the workq context; because we don't have a
* generic workq wrapper yet.
*
* @param arg Instance pointer for the driver that is polling.
*/
static void cycle_trampoline(void *arg);
};
/* helper macro for handling report buffer indices */
#define INCREMENT(_x, _lim) do { _x++; if (_x >= _lim) _x = 0; } while(0)
/*
* Driver 'main' command.
*/
extern "C" __EXPORT int ets_airspeed_main(int argc, char *argv[]);
ETSAirspeed::ETSAirspeed(int bus, int address) :
I2C("ETSAirspeed", AIRSPEED_DEVICE_PATH, bus, address, 100000),
_num_reports(0),
_next_report(0),
_oldest_report(0),
_reports(nullptr),
_sensor_ok(false),
_measure_ticks(0),
_collect_phase(false),
_diff_pres_offset(0.0f),
_airspeed_pub(-1),
_sample_perf(perf_alloc(PC_ELAPSED, "ets_airspeed_read")),
_comms_errors(perf_alloc(PC_COUNT, "ets_airspeed_comms_errors")),
_buffer_overflows(perf_alloc(PC_COUNT, "ets_airspeed_buffer_overflows"))
{
// enable debug() calls
_debug_enabled = true;
// work_cancel in the dtor will explode if we don't do this...
memset(&_work, 0, sizeof(_work));
}
ETSAirspeed::~ETSAirspeed()
{
/* make sure we are truly inactive */
stop();
/* free any existing reports */
if (_reports != nullptr)
delete[] _reports;
}
int
ETSAirspeed::init()
{
int ret = ERROR;
/* do I2C init (and probe) first */
if (I2C::init() != OK)
goto out;
/* allocate basic report buffers */
_num_reports = 2;
_reports = new struct differential_pressure_s[_num_reports];
for (unsigned i = 0; i < _num_reports; i++)
_reports[i].max_differential_pressure_pa = 0;
if (_reports == nullptr)
goto out;
_oldest_report = _next_report = 0;
/* get a publish handle on the airspeed topic */
memset(&_reports[0], 0, sizeof(_reports[0]));
_airspeed_pub = orb_advertise(ORB_ID(differential_pressure), &_reports[0]);
if (_airspeed_pub < 0)
debug("failed to create airspeed sensor object. Did you start uOrb?");
ret = OK;
/* sensor is ok, but we don't really know if it is within range */
_sensor_ok = true;
out:
return ret;
}
int
ETSAirspeed::probe()
{
return measure();
}
int
ETSAirspeed::ioctl(struct file *filp, int cmd, unsigned long arg)
{
switch (cmd) {
case SENSORIOCSPOLLRATE: {
switch (arg) {
/* switching to manual polling */
case SENSOR_POLLRATE_MANUAL:
stop();
_measure_ticks = 0;
return OK;
/* external signalling (DRDY) not supported */
case SENSOR_POLLRATE_EXTERNAL:
/* zero would be bad */
case 0:
return -EINVAL;
/* set default/max polling rate */
case SENSOR_POLLRATE_MAX:
case SENSOR_POLLRATE_DEFAULT: {
/* do we need to start internal polling? */
bool want_start = (_measure_ticks == 0);
/* set interval for next measurement to minimum legal value */
_measure_ticks = USEC2TICK(CONVERSION_INTERVAL);
/* if we need to start the poll state machine, do it */
if (want_start)
start();
return OK;
}
/* adjust to a legal polling interval in Hz */
default: {
/* do we need to start internal polling? */
bool want_start = (_measure_ticks == 0);
/* convert hz to tick interval via microseconds */
unsigned ticks = USEC2TICK(1000000 / arg);
/* check against maximum rate */
if (ticks < USEC2TICK(CONVERSION_INTERVAL))
return -EINVAL;
/* update interval for next measurement */
_measure_ticks = ticks;
/* if we need to start the poll state machine, do it */
if (want_start)
start();
return OK;
}
}
}
case SENSORIOCGPOLLRATE:
if (_measure_ticks == 0)
return SENSOR_POLLRATE_MANUAL;
return (1000 / _measure_ticks);
case SENSORIOCSQUEUEDEPTH: {
/* add one to account for the 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 differential_pressure_s *buf = new struct differential_pressure_s[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 this */
return -EINVAL;
case AIRSPEEDIOCSSCALE: {
struct airspeed_scale *s = (struct airspeed_scale*)arg;
_diff_pres_offset = s->offset_pa;
return OK;
}
case AIRSPEEDIOCGSCALE: {
struct airspeed_scale *s = (struct airspeed_scale*)arg;
s->offset_pa = _diff_pres_offset;
s->scale = 1.0f;
return OK;
}
default:
/* give it to the superclass */
return I2C::ioctl(filp, cmd, arg);
}
}
ssize_t
ETSAirspeed::read(struct file *filp, char *buffer, size_t buflen)
{
unsigned count = buflen / sizeof(struct differential_pressure_s);
int ret = 0;
/* buffer must be large enough */
if (count < 1)
return -ENOSPC;
/* if automatic measurement is enabled */
if (_measure_ticks > 0) {
/*
* While there is space in the caller's buffer, and reports, copy them.
* Note that we may be pre-empted by the workq thread while we are doing this;
* we are careful to avoid racing with them.
*/
while (count--) {
if (_oldest_report != _next_report) {
memcpy(buffer, _reports + _oldest_report, sizeof(*_reports));
ret += sizeof(_reports[0]);
INCREMENT(_oldest_report, _num_reports);
}
}
/* if there was no data, warn the caller */
return ret ? ret : -EAGAIN;
}
/* manual measurement - run one conversion */
/* XXX really it'd be nice to lock against other readers here */
do {
_oldest_report = _next_report = 0;
/* trigger a measurement */
if (OK != measure()) {
ret = -EIO;
break;
}
/* wait for it to complete */
usleep(CONVERSION_INTERVAL);
/* run the collection phase */
if (OK != collect()) {
ret = -EIO;
break;
}
/* state machine will have generated a report, copy it out */
memcpy(buffer, _reports, sizeof(*_reports));
ret = sizeof(*_reports);
} while (0);
return ret;
}
int
ETSAirspeed::measure()
{
int ret;
/*
* Send the command to begin a measurement.
*/
uint8_t cmd = READ_CMD;
ret = transfer(&cmd, 1, nullptr, 0);
if (OK != ret) {
perf_count(_comms_errors);
log("i2c::transfer returned %d", ret);
return ret;
}
ret = OK;
return ret;
}
int
ETSAirspeed::collect()
{
int ret = -EIO;
/* read from the sensor */
uint8_t val[2] = {0, 0};
perf_begin(_sample_perf);
ret = transfer(nullptr, 0, &val[0], 2);
if (ret < 0) {
log("error reading from sensor: %d", ret);
return ret;
}
uint16_t diff_pres_pa = val[1] << 8 | val[0];
if (diff_pres_pa < _diff_pres_offset + MIN_ACCURATE_DIFF_PRES_PA) {
diff_pres_pa = 0;
} else {
diff_pres_pa -= _diff_pres_offset;
}
// XXX we may want to smooth out the readings to remove noise.
_reports[_next_report].timestamp = hrt_absolute_time();
_reports[_next_report].differential_pressure_pa = diff_pres_pa;
// Track maximum differential pressure measured (so we can work out top speed).
if (diff_pres_pa > _reports[_next_report].max_differential_pressure_pa) {
_reports[_next_report].max_differential_pressure_pa = diff_pres_pa;
}
/* announce the airspeed if needed, just publish else */
orb_publish(ORB_ID(differential_pressure), _airspeed_pub, &_reports[_next_report]);
/* post a report to the ring - note, not locked */
INCREMENT(_next_report, _num_reports);
/* if we are running up against the oldest report, toss it */
if (_next_report == _oldest_report) {
perf_count(_buffer_overflows);
INCREMENT(_oldest_report, _num_reports);
}
/* notify anyone waiting for data */
poll_notify(POLLIN);
ret = OK;
perf_end(_sample_perf);
return ret;
}
void
ETSAirspeed::start()
{
/* reset the report ring and state machine */
_collect_phase = false;
_oldest_report = _next_report = 0;
/* schedule a cycle to start things */
work_queue(HPWORK, &_work, (worker_t)&ETSAirspeed::cycle_trampoline, this, 1);
/* notify about state change */
struct subsystem_info_s info = {
true,
true,
true,
SUBSYSTEM_TYPE_DIFFPRESSURE
};
static orb_advert_t pub = -1;
if (pub > 0) {
orb_publish(ORB_ID(subsystem_info), pub, &info);
} else {
pub = orb_advertise(ORB_ID(subsystem_info), &info);
}
}
void
ETSAirspeed::stop()
{
work_cancel(HPWORK, &_work);
}
void
ETSAirspeed::cycle_trampoline(void *arg)
{
ETSAirspeed *dev = (ETSAirspeed *)arg;
dev->cycle();
}
void
ETSAirspeed::cycle()
{
/* collection phase? */
if (_collect_phase) {
/* perform collection */
if (OK != collect()) {
log("collection error");
/* restart the measurement state machine */
start();
return;
}
/* next phase is measurement */
_collect_phase = false;
/*
* Is there a collect->measure gap?
*/
if (_measure_ticks > USEC2TICK(CONVERSION_INTERVAL)) {
/* schedule a fresh cycle call when we are ready to measure again */
work_queue(HPWORK,
&_work,
(worker_t)&ETSAirspeed::cycle_trampoline,
this,
_measure_ticks - USEC2TICK(CONVERSION_INTERVAL));
return;
}
}
/* measurement phase */
if (OK != measure())
log("measure error");
/* next phase is collection */
_collect_phase = true;
/* schedule a fresh cycle call when the measurement is done */
work_queue(HPWORK,
&_work,
(worker_t)&ETSAirspeed::cycle_trampoline,
this,
USEC2TICK(CONVERSION_INTERVAL));
}
void
ETSAirspeed::print_info()
{
perf_print_counter(_sample_perf);
perf_print_counter(_comms_errors);
perf_print_counter(_buffer_overflows);
printf("poll interval: %u ticks\n", _measure_ticks);
printf("report queue: %u (%u/%u @ %p)\n",
_num_reports, _oldest_report, _next_report, _reports);
}
/**
* Local functions in support of the shell command.
*/
namespace ets_airspeed
{
/* oddly, ERROR is not defined for c++ */
#ifdef ERROR
# undef ERROR
#endif
const int ERROR = -1;
ETSAirspeed *g_dev;
void start(int i2c_bus);
void stop();
void test();
void reset();
void info();
/**
* Start the driver.
*/
void
start(int i2c_bus)
{
int fd;
if (g_dev != nullptr)
errx(1, "already started");
/* create the driver */
g_dev = new ETSAirspeed(i2c_bus);
if (g_dev == nullptr)
goto fail;
if (OK != g_dev->init())
goto fail;
/* set the poll rate to default, starts automatic data collection */
fd = open(AIRSPEED_DEVICE_PATH, O_RDONLY);
if (fd < 0)
goto fail;
if (ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT) < 0)
goto fail;
exit(0);
fail:
if (g_dev != nullptr) {
delete g_dev;
g_dev = nullptr;
}
errx(1, "driver start failed");
}
/**
* Stop the driver
*/
void
stop()
{
if (g_dev != nullptr) {
delete g_dev;
g_dev = nullptr;
} else {
errx(1, "driver not running");
}
exit(0);
}
/**
* Perform some basic functional tests on the driver;
* make sure we can collect data from the sensor in polled
* and automatic modes.
*/
void
test()
{
struct differential_pressure_s report;
ssize_t sz;
int ret;
int fd = open(AIRSPEED_DEVICE_PATH, O_RDONLY);
if (fd < 0)
err(1, "%s open failed (try 'ets_airspeed start' if the driver is not running", AIRSPEED_DEVICE_PATH);
/* do a simple demand read */
sz = read(fd, &report, sizeof(report));
if (sz != sizeof(report))
err(1, "immediate read failed");
warnx("single read");
warnx("diff pressure: %d pa", report.differential_pressure_pa);
/* start the sensor polling at 2Hz */
if (OK != ioctl(fd, SENSORIOCSPOLLRATE, 2))
errx(1, "failed to set 2Hz poll rate");
/* read the sensor 5x and report each value */
for (unsigned i = 0; i < 5; i++) {
struct pollfd fds;
/* wait for data to be ready */
fds.fd = fd;
fds.events = POLLIN;
ret = poll(&fds, 1, 2000);
if (ret != 1)
errx(1, "timed out waiting for sensor data");
/* now go get it */
sz = read(fd, &report, sizeof(report));
if (sz != sizeof(report))
err(1, "periodic read failed");
warnx("periodic read %u", i);
warnx("diff pressure: %d pa", report.differential_pressure_pa);
}
errx(0, "PASS");
}
/**
* Reset the driver.
*/
void
reset()
{
int fd = open(AIRSPEED_DEVICE_PATH, O_RDONLY);
if (fd < 0)
err(1, "failed ");
if (ioctl(fd, SENSORIOCRESET, 0) < 0)
err(1, "driver reset failed");
if (ioctl(fd, SENSORIOCSPOLLRATE, SENSOR_POLLRATE_DEFAULT) < 0)
err(1, "driver poll restart failed");
exit(0);
}
/**
* Print a little info about the driver.
*/
void
info()
{
if (g_dev == nullptr)
errx(1, "driver not running");
printf("state @ %p\n", g_dev);
g_dev->print_info();
exit(0);
}
} // namespace
static void
ets_airspeed_usage()
{
fprintf(stderr, "usage: ets_airspeed command [options]\n");
fprintf(stderr, "options:\n");
fprintf(stderr, "\t-b --bus i2cbus (%d)\n", PX4_I2C_BUS_DEFAULT);
fprintf(stderr, "command:\n");
fprintf(stderr, "\tstart|stop|reset|test|info\n");
}
int
ets_airspeed_main(int argc, char *argv[])
{
int i2c_bus = PX4_I2C_BUS_DEFAULT;
int i;
for (i = 1; i < argc; i++) {
if (strcmp(argv[i], "-b") == 0 || strcmp(argv[i], "--bus") == 0) {
if (argc > i + 1) {
i2c_bus = atoi(argv[i + 1]);
}
}
}
/*
* Start/load the driver.
*/
if (!strcmp(argv[1], "start"))
ets_airspeed::start(i2c_bus);
/*
* Stop the driver
*/
if (!strcmp(argv[1], "stop"))
ets_airspeed::stop();
/*
* Test the driver/device.
*/
if (!strcmp(argv[1], "test"))
ets_airspeed::test();
/*
* Reset the driver.
*/
if (!strcmp(argv[1], "reset"))
ets_airspeed::reset();
/*
* Print driver information.
*/
if (!strcmp(argv[1], "info") || !strcmp(argv[1], "status"))
ets_airspeed::info();
ets_airspeed_usage();
exit(0);
}