PX4-Autopilot/src/drivers/airspeed/airspeed.h

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 * modification, are permitted provided that the following conditions
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/**
 * @file airspeed.h
 * @author Simon Wilks
 *
 * Generic driver for airspeed sensors connected via I2C.
 */

#include <nuttx/config.h>

#include <drivers/device/i2c.h>

#include <sys/types.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdbool.h>
#include <semaphore.h>
#include <string.h>
#include <fcntl.h>
#include <poll.h>
#include <errno.h>
#include <stdio.h>
#include <math.h>
#include <unistd.h>

#include <nuttx/arch.h>
#include <nuttx/wqueue.h>
#include <nuttx/clock.h>

#include <arch/board/board.h>

#include <systemlib/airspeed.h>
#include <systemlib/err.h>
#include <systemlib/param/param.h>
#include <systemlib/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 <uORB/topics/subsystem_info.h>

/* Default I2C bus */
#define PX4_I2C_BUS_DEFAULT		PX4_I2C_BUS_EXPANSION

/* Oddly, ERROR is not defined for C++ */
#ifdef ERROR
# undef ERROR
#endif
static const int ERROR = -1;

#ifndef CONFIG_SCHED_WORKQUEUE
# error This requires CONFIG_SCHED_WORKQUEUE.
#endif

class __EXPORT Airspeed : public device::I2C
{
public:
	Airspeed(int bus, int address, unsigned conversion_interval, const char* path);
	virtual ~Airspeed();

	virtual int	init();

	virtual ssize_t	read(struct file *filp, char *buffer, size_t buflen);
	virtual int	ioctl(struct file *filp, int cmd, unsigned long arg);

	/**
	 * Diagnostics - print some basic information about the driver.
	 */
	virtual void	print_info();

private:
	RingBuffer		*_reports;
	perf_counter_t		_buffer_overflows;

protected:
	virtual int	probe();

	/**
	* Perform a poll cycle; collect from the previous measurement
	* and start a new one.
	*/
	virtual void	cycle() = 0;
	virtual int	measure() = 0;
	virtual int	collect() = 0;

	work_s			_work;
	float			_max_differential_pressure_pa;
	bool			_sensor_ok;
	int			_measure_ticks;
	bool			_collect_phase;
	float			_diff_pres_offset;

	orb_advert_t		_airspeed_pub;

	int			_class_instance;

	unsigned		_conversion_interval;

	perf_counter_t		_sample_perf;
	perf_counter_t		_comms_errors;


	/**
	* Test whether the device supported by the driver is present at a
	* specific address.
	*
	* @param address	The I2C bus address to probe.
	* @return		True if the device is present.
	*/
	int	probe_address(uint8_t address);

	/**
	* Initialise the automatic measurement state machine and start it.
	*
	* @note This function is called at open and error time.  It might make sense
	*       to make it more aggressive about resetting the bus in case of errors.
	*/
	void	start();

	/**
	* Stop the automatic measurement state machine.
	*/
	void	stop();

	/**
	* Static trampoline from the workq context; because we don't have a
	* generic workq wrapper yet.
	*
	* @param arg		Instance pointer for the driver that is polling.
	*/
	static void	cycle_trampoline(void *arg);

	/**
	* add a new report to the reports queue
	*
	* @param report		differential_pressure_s report
	*/
	void	new_report(const differential_pressure_s &report);
};