ardupilot/libraries/AP_RangeFinder/AP_RangeFinder_LightWareI2C...

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/*
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_RangeFinder_LightWareI2C.h"
#include <utility>
#include <AP_HAL/AP_HAL.h>
#include <AP_HAL/utility/sparse-endian.h>
extern const AP_HAL::HAL& hal;
/*
The constructor also initializes 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_LightWareI2C::AP_RangeFinder_LightWareI2C(RangeFinder::RangeFinder_State &_state, AP_HAL::OwnPtr<AP_HAL::I2CDevice> dev)
: AP_RangeFinder_Backend(_state)
, _dev(std::move(dev)) {}
/*
detect if a Lightware rangefinder is connected. We'll detect by
trying to take a reading on I2C. If we get a result the sensor is
there.
*/
AP_RangeFinder_Backend *AP_RangeFinder_LightWareI2C::detect(RangeFinder::RangeFinder_State &_state, AP_HAL::OwnPtr<AP_HAL::I2CDevice> dev)
{
AP_RangeFinder_LightWareI2C *sensor
= new AP_RangeFinder_LightWareI2C(_state, std::move(dev));
if (!sensor) {
delete sensor;
return nullptr;
}
if (sensor->_dev->get_semaphore()->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
uint16_t reading_cm;
if (!sensor->get_reading(reading_cm)) {
sensor->_dev->get_semaphore()->give();
delete sensor;
return nullptr;
}
sensor->_dev->get_semaphore()->give();
}
sensor->init();
return sensor;
}
void AP_RangeFinder_LightWareI2C::init()
{
// call timer() at 20Hz
_dev->register_periodic_callback(50000,
FUNCTOR_BIND_MEMBER(&AP_RangeFinder_LightWareI2C::timer, void));
}
// read - return last value measured by sensor
bool AP_RangeFinder_LightWareI2C::get_reading(uint16_t &reading_cm)
{
be16_t val;
if (state.address == 0) {
return false;
}
// read the high and low byte distance registers
bool ret = _dev->read((uint8_t *) &val, sizeof(val));
if (ret) {
// combine results into distance
reading_cm = be16toh(val);
}
return ret;
}
/*
update the state of the sensor
*/
void AP_RangeFinder_LightWareI2C::update(void)
{
// nothing to do - its all done in the timer()
}
void AP_RangeFinder_LightWareI2C::timer(void)
{
if (get_reading(state.distance_cm)) {
// update range_valid state based on distance measured
update_status();
} else {
set_status(RangeFinder::RangeFinder_NoData);
}
}