Abstract class for any character device. More...

#include <CDev.hpp>

Inheritance diagram for cdev::CDev:

Public Member Functions
	CDev (const char *devname)
	Constructor. More...

virtual int	init ()

virtual int	open (file_t *filep)
	Handle an open of the device. More...

virtual int	close (file_t *filep)
	Handle a close of the device. More...

virtual ssize_t	read (file_t filep, char buffer, size_t buflen)
	Perform a read from the device. More...

virtual ssize_t	write (file_t filep, const char buffer, size_t buflen)
	Perform a write to the device. More...

virtual off_t	seek (file_t *filep, off_t offset, int whence)
	Perform a logical seek operation on the device. More...

virtual int	ioctl (file_t *filep, int cmd, unsigned long arg)
	Perform an ioctl operation on the device. More...

virtual int	poll (file_t filep, px4_pollfd_struct_t fds, bool setup)
	Perform a poll setup/teardown operation. More...

const char *	get_devname () const
	Get the device name. More...

Protected Member Functions
virtual pollevent_t	poll_state (file_t *filep)
	Check the current state of the device for poll events from the perspective of the file. More...

virtual void	poll_notify (pollevent_t events)
	Report new poll events. More...

virtual void	poll_notify_one (px4_pollfd_struct_t *fds, pollevent_t events)
	Internal implementation of poll_notify. More...

virtual int	open_first (file_t *filep)
	Notification of the first open. More...

virtual int	close_last (file_t *filep)
	Notification of the last close. More...

virtual int	register_class_devname (const char *class_devname)
	Register a class device name, automatically adding device class instance suffix if need be. More...

virtual int	unregister_class_devname (const char *class_devname, unsigned class_instance)
	Register a class device name, automatically adding device class instance suffix if need be. More...

void	lock ()
	Take the driver lock. More...

void	unlock ()
	Release the driver lock.

Protected Attributes
px4_sem_t	_lock
	lock to protect access to all class members (also for derived classes)

Static Protected Attributes
static const px4_file_operations_t	fops = {}
	Pointer to the default cdev file operations table; useful for registering clone devices etc.

Detailed Description

Abstract class for any character device.

Constructor & Destructor Documentation

§ CDev()

CDev::CDev ( const char * devname )

Constructor.

Parameters

name	Driver name
devname	Device node name

Member Function Documentation

§ close()

int CDev::close ( file_t * filep )

virtual

Handle a close of the device.

This function is called for every close of the device. The default implementation maintains _open_count and returns OK as long as it is not zero.

Parameters

filep Pointer to the NuttX file structure.

Returns: OK if the close was successful, -errno otherwise.

Reimplemented in CDevNode, and uORB::DeviceNode.

§ close_last()

virtual int cdev::CDev::close_last ( file_t * filep )

inlineprotectedvirtual

Notification of the last close.

This function is called when the device open count transitions from one to zero. The driver lock is held for the duration of the call.

The default implementation returns OK.

Parameters

filep Pointer to the NuttX file structure.

Returns: OK if the open should return OK, -errno otherwise.

§ get_devname()

const char* cdev::CDev::get_devname ( ) const

inline

Get the device name.

Returns: the file system string of the device handle

§ ioctl()

int CDev::ioctl	(	file_t *	filep,
		int	cmd,
		unsigned long	arg
	)

virtual

Perform an ioctl operation on the device.

The default implementation handles DIOC_GETPRIV, and otherwise returns -ENOTTY. Subclasses should call the default implementation for any command they do not handle themselves.

Parameters

filep	Pointer to the NuttX file structure.
cmd	The ioctl command value.
arg	The ioctl argument value.

Returns: OK on success, or -errno otherwise.

Reimplemented in TAP_ESC, uORB::DeviceNode, TFMINI, CM8JL65, HC_SR04, SF0X, PWMSim, AirspeedSim, device::CDev, LED, PX4Magnetometer, PX4Accelerometer, and PX4Gyroscope.

§ lock()

void cdev::CDev::lock ( )

inlineprotected

Take the driver lock.

Each driver instance has its own lock/semaphore.

Note that we must loop as the wait may be interrupted by a signal.

Careful: lock() calls cannot be nested!

§ open()

int CDev::open ( file_t * filep )

virtual

Handle an open of the device.

This function is called for every open of the device. The default implementation maintains _open_count and always returns OK.

Parameters

filep Pointer to the NuttX file structure.

Returns: OK if the open is allowed, -errno otherwise.

Reimplemented in CDevNode, and uORB::DeviceNode.

§ open_first()

virtual int cdev::CDev::open_first ( file_t * filep )

inlineprotectedvirtual

Notification of the first open.

This function is called when the device open count transitions from zero to one. The driver lock is held for the duration of the call.

The default implementation returns OK.

Parameters

filep Pointer to the NuttX file structure.

Returns: OK if the open should proceed, -errno otherwise.

§ poll()

int CDev::poll	(	file_t *	filep,
		px4_pollfd_struct_t *	fds,
		bool	setup
	)

virtual

Perform a poll setup/teardown operation.

This is handled internally and should not normally be overridden.

Parameters

filep	Pointer to the internal file structure.
fds	Poll descriptor being waited on.
setup	True if this is establishing a request, false if it is being torn down.

Returns: OK on success, or -errno otherwise.

§ poll_notify()

void CDev::poll_notify ( pollevent_t events )

protectedvirtual

Report new poll events.

This function should be called anytime the state of the device changes in a fashion that might be interesting to a poll waiter.

Parameters

events The new event(s) being announced.

§ poll_notify_one()

void CDev::poll_notify_one	(	px4_pollfd_struct_t *	fds,
		pollevent_t	events
	)

protectedvirtual

Internal implementation of poll_notify.

Parameters

fds	A poll waiter to notify.
events	The event(s) to send to the waiter.

Reimplemented in uORB::DeviceNode.

§ poll_state()

virtual pollevent_t cdev::CDev::poll_state ( file_t * filep )

inlineprotectedvirtual

Check the current state of the device for poll events from the perspective of the file.

This function is called by the default poll() implementation when a poll is set up to determine whether the poll should return immediately.

The default implementation returns no events.

Parameters

filep The file that's interested.

Returns: The current set of poll events.

Reimplemented in uORB::DeviceNode.

§ read()

virtual ssize_t cdev::CDev::read	(	file_t *	filep,
		char *	buffer,
		size_t	buflen
	)

inlinevirtual

Perform a read from the device.

The default implementation returns -ENOSYS.

Parameters

filep	Pointer to the NuttX file structure.
buffer	Pointer to the buffer into which data should be placed.
buflen	The number of bytes to be read.

Returns: The number of bytes read or -errno otherwise.

Reimplemented in CDevNode, TFMINI, HC_SR04, SF0X, uORB::DeviceNode, AirspeedSim, and LidarLitePWM.

§ register_class_devname()

int CDev::register_class_devname ( const char * class_devname )

protectedvirtual

Register a class device name, automatically adding device class instance suffix if need be.

Parameters

class_devname Device class name

Returns: class_instamce Class instance created, or -errno on failure

§ seek()

virtual off_t cdev::CDev::seek	(	file_t *	filep,
		off_t	offset,
		int	whence
	)

inlinevirtual

Perform a logical seek operation on the device.

The default implementation returns -ENOSYS.

Parameters

filep	Pointer to the NuttX file structure.
offset	The new file position relative to whence.
whence	SEEK_OFS, SEEK_CUR or SEEK_END.

Returns: The previous offset, or -errno otherwise.

§ unregister_class_devname()

int CDev::unregister_class_devname	(	const char *	class_devname,
		unsigned	class_instance
	)

protectedvirtual

Register a class device name, automatically adding device class instance suffix if need be.

Parameters

class_devname	Device class name
class_instance	Device class instance from register_class_devname()

Returns: OK on success, -errno otherwise

§ write()

virtual ssize_t cdev::CDev::write	(	file_t *	filep,
		const char *	buffer,
		size_t	buflen
	)

inlinevirtual

Perform a write to the device.

The default implementation returns -ENOSYS.

Parameters

filep	Pointer to the NuttX file structure.
buffer	Pointer to the buffer from which data should be read.
buflen	The number of bytes to be written.

Returns: The number of bytes written or -errno otherwise.

Reimplemented in CDevNode, uORB::DeviceNode, and cdev::VFile.

The documentation for this class was generated from the following files:

src/lib/cdev/CDev.hpp
src/lib/cdev/CDev.cpp
src/lib/cdev/posix/cdev_platform.cpp

Public Member Functions

Protected Member Functions

Protected Attributes

Static Protected Attributes

Detailed Description

Constructor & Destructor Documentation

§ CDev()

Member Function Documentation

§ close()

§ close_last()

§ get_devname()

§ ioctl()

§ lock()

§ open()

§ open_first()

§ poll()

§ poll_notify()

§ poll_notify_one()

§ poll_state()

§ read()

§ register_class_devname()

§ seek()

§ unregister_class_devname()

§ write()