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/**
* @author Pavel Kirienko <pavel.kirienko@gmail.com>
*/
#include "baro.hpp"
#include <cmath>
const char *const UavcanBarometerBridge::NAME = "baro";
UavcanBarometerBridge::UavcanBarometerBridge(uavcan::INode& node) :
device::CDev("uavcan_baro", "/dev/uavcan/baro"),
_sub_air_data(node)
{
}
UavcanBarometerBridge::~UavcanBarometerBridge()
{
if (_class_instance > 0) {
(void)unregister_class_devname(BARO_DEVICE_PATH, _class_instance);
}
}
int UavcanBarometerBridge::init()
{
// Init the libuavcan subscription
int 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;
}
// Detect our device class
_class_instance = register_class_devname(BARO_DEVICE_PATH);
switch (_class_instance) {
case CLASS_DEVICE_PRIMARY: {
_orb_id = ORB_ID(sensor_baro0);
break;
}
case CLASS_DEVICE_SECONDARY: {
_orb_id = ORB_ID(sensor_baro1);
break;
}
default: {
log("invalid class instance: %d", _class_instance);
(void)unregister_class_devname(BARO_DEVICE_PATH, _class_instance);
return -1;
}
}
log("inited with class instance %d", _class_instance);
return 0;
}
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;
}
default: {
return CDev::ioctl(filp, cmd, arg);
}
}
}
void UavcanBarometerBridge::air_data_sub_cb(const uavcan::ReceivedDataStructure<uavcan::equipment::air_data::StaticAirData> &msg)
{
auto report = ::baro_report();
report.timestamp = msg.getUtcTimestamp().toUSec();
if (report.timestamp == 0) {
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
*/
if (_orb_advert >= 0) {
orb_publish(_orb_id, _orb_advert, &report);
} else {
_orb_advert = orb_advertise(_orb_id, &report);
if (_orb_advert < 0) {
log("ADVERT FAIL");
} else {
log("advertised");
}
}
}