ardupilot/libraries/AP_RangeFinder/AP_RangeFinder_PX4.cpp

133 lines
3.5 KiB
C++

// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
/*
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <AP_HAL.h>
#if CONFIG_HAL_BOARD == HAL_BOARD_PX4
#include "AP_RangeFinder_PX4.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <drivers/drv_range_finder.h>
#include <drivers/drv_hrt.h>
#include <stdio.h>
#include <errno.h>
extern const AP_HAL::HAL& hal;
uint8_t AP_RangeFinder_PX4::num_px4_instances = 0;
/*
The constructor also initialises the rangefinder. Note that this
constructor is not called until detect() returns true, so we
already know that we should setup the rangefinder
*/
AP_RangeFinder_PX4::AP_RangeFinder_PX4(RangeFinder &_ranger, uint8_t instance, RangeFinder::RangeFinder_State &_state) :
AP_RangeFinder_Backend(_ranger, instance, _state)
{
_fd = open_driver();
// consider this path used up
num_px4_instances++;
if (_fd == -1) {
hal.console->printf("Unable to open PX4 rangefinder %u\n", num_px4_instances);
state.healthy = false;
return;
}
// average over up to 20 samples
if (ioctl(_fd, SENSORIOCSQUEUEDEPTH, 20) != 0) {
hal.console->printf("Failed to setup range finder queue\n");
state.healthy = false;
return;
}
state.healthy = true;
}
/*
close the file descriptor
*/
AP_RangeFinder_PX4::~AP_RangeFinder_PX4()
{
if (_fd != -1) {
close(_fd);
}
}
/*
open the PX4 driver, returning the file descriptor
*/
int AP_RangeFinder_PX4::open_driver(void)
{
// work out the device path based on how many PX4 drivers we have loaded
char path[] = RANGE_FINDER_DEVICE_PATH "n";
if (num_px4_instances == 0) {
path[strlen(path)-1] = 0;
} else {
path[strlen(path)-1] = '1' + (num_px4_instances-1);
}
return open(path, O_RDONLY);
}
/*
see if the PX4 driver is available
*/
bool AP_RangeFinder_PX4::detect(RangeFinder &_ranger, uint8_t instance)
{
int fd = open_driver();
if (fd == -1) {
return false;
}
close(fd);
return true;
}
void AP_RangeFinder_PX4::update(void)
{
if (_fd == -1) {
state.healthy = false;
return;
}
struct range_finder_report range_report;
float sum = 0;
uint16_t count = 0;
while (::read(_fd, &range_report, sizeof(range_report)) == sizeof(range_report) &&
range_report.timestamp != _last_timestamp) {
// Only take valid readings
if (range_report.valid == 1) {
sum += range_report.distance;
count++;
_last_timestamp = range_report.timestamp;
}
}
// consider the range finder healthy if we got a reading in the last 0.2s
state.healthy = (hrt_absolute_time() - _last_timestamp < 200000);
if (count != 0) {
state.distance_cm = sum / count * 100.0f;
}
}
#endif // CONFIG_HAL_BOARD