Private data for an SPI device. More...

#include <SPI.hxx>

Inheritance diagram for SPI:

Public Types
typedef void(*	ChipSelectMethod) ()
	Function point for the chip select assert and deassert methods.

Public Member Functions
int	transfer_with_cs_assert (struct spi_ioc_transfer *msg)
	Method to transmit/receive the data.

int	transfer_with_cs_assert_polled (struct spi_ioc_transfer *msgs, int num=1)
	Method to transmit/receive the data.

int	transfer_messages (struct spi_ioc_transfer *msgs, int num)
	Conduct multiple message transfers with one stop at the end.

Public Member Functions inherited from Device
	Device (const char *name)
	Constructor.

virtual	~Device ()
	Destructor.

Protected Member Functions
	SPI (const char name, ChipSelectMethod cs_assert, ChipSelectMethod cs_deassert, OSMutex bus_lock=nullptr)
	Constructor.

	~SPI ()
	Destructor.

void	bus_lock ()
	Lock the bus shared by many chip selects.

void	bus_unlock ()
	Unlock the bus shared by many chip selects.

virtual int	transfer (struct spi_ioc_transfer *msg)=0
	Method to transmit/receive the data.

virtual int	transfer_polled (struct spi_ioc_transfer *msg)=0
	Method to transmit/receive the data, but always in polled mode.

virtual int	update_configuration ()=0
	Update the configuration of the bus.

int	ioctl (File *file, unsigned long int key, unsigned long data) override
	Request an ioctl transaction.

Protected Member Functions inherited from Node
	Node (const char *name)
	Constructor.

virtual	~Node ()
	Destructor.

virtual void	enable ()=0
	This will be called once when reference-count goes from 0 to positive.

virtual void	disable ()=0
	This will be called when reference count goes from non-zero to 0.

int	open (File , const char , int, int) OVERRIDE
	Open method.

int	close (File *) OVERRIDE
	Close method.

virtual int	fstat (File file, struct stat stat) override
	Get the status information of a file or device.

Protected Member Functions inherited from FileIO
	FileIO (const char *name)
	Constructor.

virtual	~FileIO ()
	Destructor.

virtual off_t	lseek (File *f, off_t offset, int whence)
	Seek method.

virtual int	fcntl (File *file, int cmd, unsigned long data)
	Manipulate a file descriptor.

virtual bool	select (File *file, int mode)
	Device select method.

Protected Attributes
ChipSelectMethod	csAssert
	function pointer to a method that asserts chip select.

ChipSelectMethod	csDeassert
	function pointer to a method that deasserts chip select.

uint32_t	speedHz
	Max default speed in Hz.

uint8_t	bitsPerWord
	number of bits per word transaction

uint8_t	mode
	one of four SPI modes

bool	lsbFirst
	transmit LSB first if true

Protected Attributes inherited from Node
OSMutex	lock_
	protects internal structures.

mode_t	mode_
	File open mode, such as O_NONBLOCK.

unsigned int	references_
	number of open references

Protected Attributes inherited from FileIO
const char *	name
	device name

Private Member Functions
ssize_t	read (File file, void buf, size_t count) override
	Read from a file or device.

ssize_t	write (File file, const void buf, size_t count) override
	Write to a file or device.

void	flush_buffers () override
	Discards all pending buffers.

	SPI ()
	Default constructor.

	DISALLOW_COPY_AND_ASSIGN (SPI)

Private Attributes
OSMutex *	busLock
	Mutual exclusion for the bus among many chip selects.

Additional Inherited Members
Static Public Member Functions inherited from Device
static int	open (struct _reent reent, const char path, int flags, int mode)
	Open a file or device.

static int	close (struct _reent *reent, int fd)
	Close a file or device.

static int	stat (struct _reent reent, const char path, struct stat *stat)
	Get the status information of a file or device.

static int	select (int nfds, fd_set readfds, fd_set writefds, fd_set *exceptfds, long long timeout)
	POSIX select().

static void	select_clear ()
	Clears the current thread's select bits.

Static Public Member Functions inherited from FileIO
static ssize_t	read (struct _reent reent, int fd, void buf, size_t count)
	Read from a file or device.

static ssize_t	write (struct _reent reent, int fd, const void buf, size_t count)
	Write to a file or device.

static _off_t	lseek (struct _reent *reent, int fd, _off_t offset, int whence)
	Change the offset index of a file or device.

static int	fstat (struct _reent reent, int fd, struct stat stat)
	Get the status information of a file or device.

static int	ioctl (int fd, unsigned long int key, unsigned long data)
	Request and ioctl transaction.

static int	fcntl (int fd, int cmd, unsigned long data)
	Manipulate a file descriptor.

static bool	is_device (int fd)
	Test if the file descriptor belongs to a device.

Static Protected Member Functions inherited from Device
static void	select_insert (SelectInfo *info)
	Add client to list of clients needing woken.

static void	select_wakeup (SelectInfo *info)
	Wakeup the list of clients needing woken.

static void	select_wakeup_from_isr (SelectInfo info, int woken)
	Wakeup the list of clients needing woken.

Static Protected Member Functions inherited from FileIO
static int	fd_alloc (void)
	Allocate a free file descriptor.

static void	fd_free (int fd)
	Free up a file descriptor.

static File *	file_lookup (int fd)
	Looks up a reference to a File corresponding to a given file descriptor.

static int	fd_lookup (File *file)
	Looks up a file descriptor corresponding to a given File reference.

Static Protected Attributes inherited from FileIO
static const unsigned int	numOpenFiles = 20

static File	files []
	File descriptor pool.

static OSMutex	mutex
	mutual exclusion for fileio

Detailed Description

Private data for an SPI device.

Unlike the Linux model this interface is based on, speed, bits per word, mode, and lsb first will always be the same for both read and write. Changing one of these parameters for read will also reflect the change in write and vice versa.

Definition at line 52 of file SPI.hxx.

Member Typedef Documentation

◆ ChipSelectMethod

typedef void(* SPI::ChipSelectMethod) ()

Function point for the chip select assert and deassert methods.

Definition at line 56 of file SPI.hxx.

Constructor & Destructor Documentation

◆ SPI()

SPI::SPI	(	const char *	name,
		ChipSelectMethod	cs_assert,
		ChipSelectMethod	cs_deassert,
		OSMutex *	bus_lock = `nullptr`
	)

inlineprotected

Constructor.

Parameters

name	device name in file system
cs_assert	function pointer to a method that asserts chip select
cs_deassert	function pointer to a method that deasserts chip select
bus_lock	the user must provide a shared mutex if the device instance represents more than one chip select on the same bus interface.

Definition at line 120 of file SPI.hxx.

◆ ~SPI()

SPI::~SPI ( )

inlineprotected

Destructor.

Definition at line 135 of file SPI.hxx.

Member Function Documentation

◆ bus_lock()

void SPI::bus_lock ( )

inlineprotected

Lock the bus shared by many chip selects.

Definition at line 141 of file SPI.hxx.

◆ bus_unlock()

void SPI::bus_unlock ( )

inlineprotected

Unlock the bus shared by many chip selects.

Definition at line 150 of file SPI.hxx.

◆ flush_buffers()

void SPI::flush_buffers ( )

inlineoverrideprivatevirtual

Discards all pending buffers.

Called after disable().

Implements Node.

Definition at line 219 of file SPI.hxx.

◆ ioctl()

int SPI::ioctl	(	File *	file,
		unsigned long int	key,
		unsigned long	data
	)

overrideprotectedvirtual

Request an ioctl transaction.

Parameters

file	file reference for this device
key	ioctl key
data	key data

Returns: >= 0 upon success, -errno upon failure

Parameters

file	file reference for this device
key	ioctl key
data	key data

Returns: 0 upon success, -errno upon failure

Reimplemented from FileIO.

Definition at line 165 of file SPI.cxx.

◆ read()

ssize_t SPI::read	(	File *	file,
		void *	buf,
		size_t	count
	)

overrideprivatevirtual

Read from a file or device.

Parameters

file	file reference for this device
buf	location to place read data
count	number of bytes to read

Returns: number of bytes read upon success, -errno upon failure

Implements FileIO.

Definition at line 93 of file SPI.cxx.

◆ transfer()

virtual int SPI::transfer ( struct spi_ioc_transfer * msg )

protectedpure virtual

Method to transmit/receive the data.

Parameters

msg	message(s) to transact.

Returns: bytes transfered upon success, -errno upon failure

Implemented in Stm32SPI, CC32xxSPI, and TivaSPI.

◆ transfer_messages()

int SPI::transfer_messages	(	struct spi_ioc_transfer *	msgs,
		int	num
	)

Conduct multiple message transfers with one stop at the end.

Parameters

msgs	array of messages to transfer
num	number of messages to transfer

Returns: total number of bytes transfered, -errno upon failure

Definition at line 49 of file SPI.cxx.

◆ transfer_polled()

virtual int SPI::transfer_polled ( struct spi_ioc_transfer * msg )

protectedpure virtual

Method to transmit/receive the data, but always in polled mode.

Parameters

msg	message(s) to transact.

Returns: bytes transfered upon success, -errno upon failure

Implemented in CC32xxSPI, TivaSPI, Stm32SPI, CC32xxSPI, and TivaSPI.

◆ transfer_with_cs_assert()

int SPI::transfer_with_cs_assert ( struct spi_ioc_transfer * msg )

inline

Method to transmit/receive the data.

Chip select will be asserted at start of the transfer and deasserted at the end of the transfer.

Parameters

msg	message(s) to transact.

Returns: bytes transfered upon success, -errno upon failure

Definition at line 64 of file SPI.hxx.

◆ transfer_with_cs_assert_polled()

int SPI::transfer_with_cs_assert_polled	(	struct spi_ioc_transfer *	msgs,
		int	num = `1`
	)

inline

Method to transmit/receive the data.

Chip select will be asserted at start of the transfer and deasserted at the end of the transfer. This will always be a polled transaction no matter what.

Parameters

msg	message(s) to transact.
num	number of messages to transfer

Returns: bytes transfered upon success, -errno upon failure

Definition at line 80 of file SPI.hxx.

◆ update_configuration()

virtual int SPI::update_configuration ( )

protectedpure virtual

Update the configuration of the bus.

Returns: >= 0 upon success, -errno upon failure

Implemented in Stm32SPI, CC32xxSPI, and TivaSPI.

◆ write()

ssize_t SPI::write	(	File *	file,
		const void *	buf,
		size_t	count
	)

overrideprivatevirtual

Write to a file or device.

Parameters

file	file reference for this device
buf	location to find write data
count	number of bytes to write

Returns: number of bytes written upon success, -errno upon failure

Implements FileIO.

Definition at line 129 of file SPI.cxx.

Member Data Documentation

◆ bitsPerWord

uint8_t SPI::bitsPerWord

protected

number of bits per word transaction

Definition at line 193 of file SPI.hxx.

◆ busLock

OSMutex* SPI::busLock

private

Mutual exclusion for the bus among many chip selects.

Definition at line 222 of file SPI.hxx.

◆ csAssert

ChipSelectMethod SPI::csAssert

protected

function pointer to a method that asserts chip select.

Definition at line 184 of file SPI.hxx.

◆ csDeassert

ChipSelectMethod SPI::csDeassert

protected

function pointer to a method that deasserts chip select.

Definition at line 187 of file SPI.hxx.

◆ lsbFirst

bool SPI::lsbFirst

protected

transmit LSB first if true

Definition at line 199 of file SPI.hxx.

◆ mode

uint8_t SPI::mode

protected

one of four SPI modes

Definition at line 196 of file SPI.hxx.

◆ speedHz

uint32_t SPI::speedHz

protected

Max default speed in Hz.

Definition at line 190 of file SPI.hxx.

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

Public Types

Public Member Functions

Protected Member Functions

Protected Attributes

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ ChipSelectMethod

Constructor & Destructor Documentation

◆ SPI()

◆ ~SPI()

Member Function Documentation

◆ bus_lock()

◆ bus_unlock()

◆ flush_buffers()

◆ ioctl()

◆ read()

◆ transfer()

◆ transfer_messages()

◆ transfer_polled()

◆ transfer_with_cs_assert()

◆ transfer_with_cs_assert_polled()

◆ update_configuration()

◆ write()

Member Data Documentation

◆ bitsPerWord

◆ busLock

◆ csAssert

◆ csDeassert

◆ lsbFirst

◆ mode

◆ speedHz