PX4-Autopilot/src/drivers/ll40ls/LidarLite.cpp

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/**
 * @file LidarLite.h
 * @author Johan Jansen <jnsn.johan@gmail.com>
 *
 * Generic interface driver for the PulsedLight Lidar-Lite range finders.
 */
#include "LidarLite.h"
#include <errno.h>
#include <nuttx/clock.h>

LidarLite::LidarLite() :
	_min_distance(LL40LS_MIN_DISTANCE),
	_max_distance(LL40LS_MAX_DISTANCE),
	_measure_ticks(0)
{
}

LidarLite::~LidarLite()
{
}

void LidarLite::set_minimum_distance(const float min)
{
	_min_distance = min;
}

void LidarLite::set_maximum_distance(const float max)
{
	_max_distance = max;
}

float LidarLite::get_minimum_distance() const
{
	return _min_distance;
}

float LidarLite::get_maximum_distance() const
{
	return _max_distance;
}

uint32_t LidarLite::getMeasureTicks() const
{
	return _measure_ticks;
}

int LidarLite::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(LL40LS_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(LL40LS_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 SENSORIOCRESET:
		reset_sensor();
		return OK;

	case RANGEFINDERIOCSETMINIUMDISTANCE: {
			set_minimum_distance(*(float *)arg);
			return OK;
		}
		break;

	case RANGEFINDERIOCSETMAXIUMDISTANCE: {
			set_maximum_distance(*(float *)arg);
			return OK;
		}
		break;

	default:
		return -EINVAL;
	}
}