bizhang_-obav/src/lib/drivers/airspeed/airspeed.cpp

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/**
 * @file airspeed.cpp
 * @author Simon Wilks <simon@px4.io>
 * @author Lorenz Meier <lorenz@px4.io>
 *
 */

#include <px4_platform_common/px4_config.h>
#include <drivers/device/device.h>

#include <drivers/device/i2c.h>

#include <systemlib/err.h>
#include <parameters/param.h>
#include <perf/perf_counter.h>

#include <drivers/drv_airspeed.h>
#include <drivers/drv_hrt.h>
#include <drivers/device/ringbuffer.h>

#include <uORB/uORB.h>
#include <uORB/topics/differential_pressure.h>

#include <drivers/airspeed/airspeed.h>

Airspeed::Airspeed(int bus, int address, unsigned conversion_interval, const char *path) :
	I2C("Airspeed", path, bus, address, 100000),
	ScheduledWorkItem(MODULE_NAME, px4::device_bus_to_wq(get_device_id())),
	_sensor_ok(false),
	_measure_interval(0),
	_collect_phase(false),
	_diff_pres_offset(0.0f),
	_airspeed_orb_class_instance(-1),
	_class_instance(-1),
	_conversion_interval(conversion_interval),
	_sample_perf(perf_alloc(PC_ELAPSED, "aspd_read")),
	_comms_errors(perf_alloc(PC_COUNT, "aspd_com_err"))
{
}

Airspeed::~Airspeed()
{
	/* make sure we are truly inactive */
	stop();

	if (_class_instance != -1) {
		unregister_class_devname(AIRSPEED_BASE_DEVICE_PATH, _class_instance);
	}

	// free perf counters
	perf_free(_sample_perf);
	perf_free(_comms_errors);
}

int
Airspeed::init()
{
	/* do I2C init (and probe) first */
	if (I2C::init() != PX4_OK) {
		return PX4_ERROR;
	}

	/* register alternate interfaces if we have to */
	_class_instance = register_class_devname(AIRSPEED_BASE_DEVICE_PATH);

	/* advertise sensor topic, measure manually to initialize valid report */
	measure();

	return PX4_OK;
}

int
Airspeed::probe()
{
	/* on initial power up the device may need more than one retry
	   for detection. Once it is running the number of retries can
	   be reduced
	*/
	_retries = 4;
	int ret = measure();

	// drop back to 2 retries once initialised
	_retries = 2;
	return ret;
}

int
Airspeed::ioctl(device::file_t *filp, int cmd, unsigned long arg)
{
	switch (cmd) {

	case SENSORIOCSPOLLRATE: {
			switch (arg) {

			/* zero would be bad */
			case 0:
				return -EINVAL;

			/* set default polling rate */
			case SENSOR_POLLRATE_DEFAULT: {
					/* do we need to start internal polling? */
					bool want_start = (_measure_interval == 0);

					/* set interval for next measurement to minimum legal value */
					_measure_interval = USEC2TICK(_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_interval == 0);

					/* convert hz to tick interval via microseconds */
					unsigned interval = (1000000 / arg);

					/* check against maximum rate */
					if (interval < _conversion_interval) {
						return -EINVAL;
					}

					/* update interval for next measurement */
					_measure_interval = interval;

					/* if we need to start the poll state machine, do it */
					if (want_start) {
						start();
					}

					return OK;
				}
			}
		}
		break;

	case AIRSPEEDIOCSSCALE: {
			struct airspeed_scale *s = (struct airspeed_scale *)arg;
			_diff_pres_offset = s->offset_pa;
			return OK;
		}

	default:
		/* give it to the superclass */
		return I2C::ioctl(filp, cmd, arg);
	}
}

void
Airspeed::start()
{
	/* reset the report ring and state machine */
	_collect_phase = false;

	/* schedule a cycle to start things */
	ScheduleNow();
}

void
Airspeed::stop()
{
	ScheduleClear();
}