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/****************************************************************************
*
* Copyright (c) 2014, 2015 PX4 Development Team. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name PX4 nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @author Pavel Kirienko <pavel.kirienko@gmail.com>
*/
#include "baro.hpp"
#include <cmath>
const char *const UavcanBarometerBridge::NAME = "baro";
UavcanBarometerBridge::UavcanBarometerBridge(uavcan::INode& node) :
UavcanCDevSensorBridgeBase("uavcan_baro", "/dev/uavcan/baro", BARO_BASE_DEVICE_PATH, ORB_ID(sensor_baro)),
_sub_air_data(node)
{
}
int UavcanBarometerBridge::init()
{
int res = device::CDev::init();
if (res < 0) {
return res;
}
res = _sub_air_data.start(AirDataCbBinder(this, &UavcanBarometerBridge::air_data_sub_cb));
if (res < 0) {
log("failed to start uavcan sub: %d", res);
return res;
}
return 0;
}
ssize_t UavcanBarometerBridge::read(struct file *filp, char *buffer, size_t buflen)
{
static uint64_t last_read = 0;
struct baro_report *baro_buf = reinterpret_cast<struct baro_report *>(buffer);
/* buffer must be large enough */
unsigned count = buflen / sizeof(struct baro_report);
if (count < 1) {
return -ENOSPC;
}
if (last_read < _report.timestamp) {
/* copy report */
lock();
*baro_buf = _report;
last_read = _report.timestamp;
unlock();
return sizeof(struct baro_report);
} else {
/* no new data available, warn caller */
return -EAGAIN;
}
}
int UavcanBarometerBridge::ioctl(struct file *filp, int cmd, unsigned long arg)
{
switch (cmd) {
case BAROIOCSMSLPRESSURE: {
if ((arg < 80000) || (arg > 120000)) {
return -EINVAL;
} else {
log("new msl pressure %u", _msl_pressure);
_msl_pressure = arg;
return OK;
}
}
case BAROIOCGMSLPRESSURE: {
return _msl_pressure;
}
case SENSORIOCSPOLLRATE: {
// not supported yet, pretend that everything is ok
return OK;
}
case SENSORIOCSQUEUEDEPTH: {
// not supported yet, pretend that everything is ok
return OK;
}
default: {
return CDev::ioctl(filp, cmd, arg);
}
}
}
void UavcanBarometerBridge::air_data_sub_cb(const uavcan::ReceivedDataStructure<uavcan::equipment::air_data::StaticAirData> &msg)
{
_report.timestamp = msg.getMonotonicTimestamp().toUSec();
_report.temperature = msg.static_temperature;
_report.pressure = msg.static_pressure / 100.0F; // Convert to millibar
/*
* Altitude computation
* Refer to the MS5611 driver for details
*/
const double T1 = 15.0 + 273.15; // temperature at base height in Kelvin
const double a = -6.5 / 1000; // temperature gradient in degrees per metre
const double g = 9.80665; // gravity constant in m/s/s
const double R = 287.05; // ideal gas constant in J/kg/K
const double p1 = _msl_pressure / 1000.0; // current pressure at MSL in kPa
const double p = double(msg.static_pressure) / 1000.0; // measured pressure in kPa
_report.altitude = (((std::pow((p / p1), (-(a * R) / g))) * T1) - T1) / a;
publish(msg.getSrcNodeID().get(), &_report);
}
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