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authorMauro Carvalho Chehab <mchehab+samsung@kernel.org>2019-06-27 20:39:22 +0200
committerMauro Carvalho Chehab <mchehab+samsung@kernel.org>2019-07-15 16:03:02 +0200
commitbaa293e9544bea71361950d071579f0e4d5713ed (patch)
tree29e0400c806016783a3fd7a380be40a201956653 /Documentation/parport-lowlevel.txt
parentdocs: admin-guide: add a series of orphaned documents (diff)
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docs: driver-api: add a series of orphaned documents
There are lots of documents under Documentation/*.txt and a few other orphan documents elsehwere that belong to the driver-API book. Move them to their right place. Reviewed-by: Cornelia Huck <cohuck@redhat.com> # vfio-related parts Acked-by: Logan Gunthorpe <logang@deltatee.com> # switchtec Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
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-===============================
-PARPORT interface documentation
-===============================
-
-:Time-stamp: <2000-02-24 13:30:20 twaugh>
-
-Described here are the following functions:
-
-Global functions::
- parport_register_driver
- parport_unregister_driver
- parport_enumerate
- parport_register_device
- parport_unregister_device
- parport_claim
- parport_claim_or_block
- parport_release
- parport_yield
- parport_yield_blocking
- parport_wait_peripheral
- parport_poll_peripheral
- parport_wait_event
- parport_negotiate
- parport_read
- parport_write
- parport_open
- parport_close
- parport_device_id
- parport_device_coords
- parport_find_class
- parport_find_device
- parport_set_timeout
-
-Port functions (can be overridden by low-level drivers):
-
- SPP::
- port->ops->read_data
- port->ops->write_data
- port->ops->read_status
- port->ops->read_control
- port->ops->write_control
- port->ops->frob_control
- port->ops->enable_irq
- port->ops->disable_irq
- port->ops->data_forward
- port->ops->data_reverse
-
- EPP::
- port->ops->epp_write_data
- port->ops->epp_read_data
- port->ops->epp_write_addr
- port->ops->epp_read_addr
-
- ECP::
- port->ops->ecp_write_data
- port->ops->ecp_read_data
- port->ops->ecp_write_addr
-
- Other::
- port->ops->nibble_read_data
- port->ops->byte_read_data
- port->ops->compat_write_data
-
-The parport subsystem comprises ``parport`` (the core port-sharing
-code), and a variety of low-level drivers that actually do the port
-accesses. Each low-level driver handles a particular style of port
-(PC, Amiga, and so on).
-
-The parport interface to the device driver author can be broken down
-into global functions and port functions.
-
-The global functions are mostly for communicating between the device
-driver and the parport subsystem: acquiring a list of available ports,
-claiming a port for exclusive use, and so on. They also include
-``generic`` functions for doing standard things that will work on any
-IEEE 1284-capable architecture.
-
-The port functions are provided by the low-level drivers, although the
-core parport module provides generic ``defaults`` for some routines.
-The port functions can be split into three groups: SPP, EPP, and ECP.
-
-SPP (Standard Parallel Port) functions modify so-called ``SPP``
-registers: data, status, and control. The hardware may not actually
-have registers exactly like that, but the PC does and this interface is
-modelled after common PC implementations. Other low-level drivers may
-be able to emulate most of the functionality.
-
-EPP (Enhanced Parallel Port) functions are provided for reading and
-writing in IEEE 1284 EPP mode, and ECP (Extended Capabilities Port)
-functions are used for IEEE 1284 ECP mode. (What about BECP? Does
-anyone care?)
-
-Hardware assistance for EPP and/or ECP transfers may or may not be
-available, and if it is available it may or may not be used. If
-hardware is not used, the transfer will be software-driven. In order
-to cope with peripherals that only tenuously support IEEE 1284, a
-low-level driver specific function is provided, for altering 'fudge
-factors'.
-
-Global functions
-================
-
-parport_register_driver - register a device driver with parport
----------------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_driver {
- const char *name;
- void (*attach) (struct parport *);
- void (*detach) (struct parport *);
- struct parport_driver *next;
- };
- int parport_register_driver (struct parport_driver *driver);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-In order to be notified about parallel ports when they are detected,
-parport_register_driver should be called. Your driver will
-immediately be notified of all ports that have already been detected,
-and of each new port as low-level drivers are loaded.
-
-A ``struct parport_driver`` contains the textual name of your driver,
-a pointer to a function to handle new ports, and a pointer to a
-function to handle ports going away due to a low-level driver
-unloading. Ports will only be detached if they are not being used
-(i.e. there are no devices registered on them).
-
-The visible parts of the ``struct parport *`` argument given to
-attach/detach are::
-
- struct parport
- {
- struct parport *next; /* next parport in list */
- const char *name; /* port's name */
- unsigned int modes; /* bitfield of hardware modes */
- struct parport_device_info probe_info;
- /* IEEE1284 info */
- int number; /* parport index */
- struct parport_operations *ops;
- ...
- };
-
-There are other members of the structure, but they should not be
-touched.
-
-The ``modes`` member summarises the capabilities of the underlying
-hardware. It consists of flags which may be bitwise-ored together:
-
- ============================= ===============================================
- PARPORT_MODE_PCSPP IBM PC registers are available,
- i.e. functions that act on data,
- control and status registers are
- probably writing directly to the
- hardware.
- PARPORT_MODE_TRISTATE The data drivers may be turned off.
- This allows the data lines to be used
- for reverse (peripheral to host)
- transfers.
- PARPORT_MODE_COMPAT The hardware can assist with
- compatibility-mode (printer)
- transfers, i.e. compat_write_block.
- PARPORT_MODE_EPP The hardware can assist with EPP
- transfers.
- PARPORT_MODE_ECP The hardware can assist with ECP
- transfers.
- PARPORT_MODE_DMA The hardware can use DMA, so you might
- want to pass ISA DMA-able memory
- (i.e. memory allocated using the
- GFP_DMA flag with kmalloc) to the
- low-level driver in order to take
- advantage of it.
- ============================= ===============================================
-
-There may be other flags in ``modes`` as well.
-
-The contents of ``modes`` is advisory only. For example, if the
-hardware is capable of DMA, and PARPORT_MODE_DMA is in ``modes``, it
-doesn't necessarily mean that DMA will always be used when possible.
-Similarly, hardware that is capable of assisting ECP transfers won't
-necessarily be used.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-Zero on success, otherwise an error code.
-
-ERRORS
-^^^^^^
-
-None. (Can it fail? Why return int?)
-
-EXAMPLE
-^^^^^^^
-
-::
-
- static void lp_attach (struct parport *port)
- {
- ...
- private = kmalloc (...);
- dev[count++] = parport_register_device (...);
- ...
- }
-
- static void lp_detach (struct parport *port)
- {
- ...
- }
-
- static struct parport_driver lp_driver = {
- "lp",
- lp_attach,
- lp_detach,
- NULL /* always put NULL here */
- };
-
- int lp_init (void)
- {
- ...
- if (parport_register_driver (&lp_driver)) {
- /* Failed; nothing we can do. */
- return -EIO;
- }
- ...
- }
-
-
-SEE ALSO
-^^^^^^^^
-
-parport_unregister_driver, parport_register_device, parport_enumerate
-
-
-
-parport_unregister_driver - tell parport to forget about this driver
---------------------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_driver {
- const char *name;
- void (*attach) (struct parport *);
- void (*detach) (struct parport *);
- struct parport_driver *next;
- };
- void parport_unregister_driver (struct parport_driver *driver);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-This tells parport not to notify the device driver of new ports or of
-ports going away. Registered devices belonging to that driver are NOT
-unregistered: parport_unregister_device must be used for each one.
-
-EXAMPLE
-^^^^^^^
-
-::
-
- void cleanup_module (void)
- {
- ...
- /* Stop notifications. */
- parport_unregister_driver (&lp_driver);
-
- /* Unregister devices. */
- for (i = 0; i < NUM_DEVS; i++)
- parport_unregister_device (dev[i]);
- ...
- }
-
-SEE ALSO
-^^^^^^^^
-
-parport_register_driver, parport_enumerate
-
-
-
-parport_enumerate - retrieve a list of parallel ports (DEPRECATED)
-------------------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport *parport_enumerate (void);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Retrieve the first of a list of valid parallel ports for this machine.
-Successive parallel ports can be found using the ``struct parport
-*next`` element of the ``struct parport *`` that is returned. If ``next``
-is NULL, there are no more parallel ports in the list. The number of
-ports in the list will not exceed PARPORT_MAX.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-A ``struct parport *`` describing a valid parallel port for the machine,
-or NULL if there are none.
-
-ERRORS
-^^^^^^
-
-This function can return NULL to indicate that there are no parallel
-ports to use.
-
-EXAMPLE
-^^^^^^^
-
-::
-
- int detect_device (void)
- {
- struct parport *port;
-
- for (port = parport_enumerate ();
- port != NULL;
- port = port->next) {
- /* Try to detect a device on the port... */
- ...
- }
- }
-
- ...
- }
-
-NOTES
-^^^^^
-
-parport_enumerate is deprecated; parport_register_driver should be
-used instead.
-
-SEE ALSO
-^^^^^^^^
-
-parport_register_driver, parport_unregister_driver
-
-
-
-parport_register_device - register to use a port
-------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- typedef int (*preempt_func) (void *handle);
- typedef void (*wakeup_func) (void *handle);
- typedef int (*irq_func) (int irq, void *handle, struct pt_regs *);
-
- struct pardevice *parport_register_device(struct parport *port,
- const char *name,
- preempt_func preempt,
- wakeup_func wakeup,
- irq_func irq,
- int flags,
- void *handle);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Use this function to register your device driver on a parallel port
-(``port``). Once you have done that, you will be able to use
-parport_claim and parport_release in order to use the port.
-
-The (``name``) argument is the name of the device that appears in /proc
-filesystem. The string must be valid for the whole lifetime of the
-device (until parport_unregister_device is called).
-
-This function will register three callbacks into your driver:
-``preempt``, ``wakeup`` and ``irq``. Each of these may be NULL in order to
-indicate that you do not want a callback.
-
-When the ``preempt`` function is called, it is because another driver
-wishes to use the parallel port. The ``preempt`` function should return
-non-zero if the parallel port cannot be released yet -- if zero is
-returned, the port is lost to another driver and the port must be
-re-claimed before use.
-
-The ``wakeup`` function is called once another driver has released the
-port and no other driver has yet claimed it. You can claim the
-parallel port from within the ``wakeup`` function (in which case the
-claim is guaranteed to succeed), or choose not to if you don't need it
-now.
-
-If an interrupt occurs on the parallel port your driver has claimed,
-the ``irq`` function will be called. (Write something about shared
-interrupts here.)
-
-The ``handle`` is a pointer to driver-specific data, and is passed to
-the callback functions.
-
-``flags`` may be a bitwise combination of the following flags:
-
- ===================== =================================================
- Flag Meaning
- ===================== =================================================
- PARPORT_DEV_EXCL The device cannot share the parallel port at all.
- Use this only when absolutely necessary.
- ===================== =================================================
-
-The typedefs are not actually defined -- they are only shown in order
-to make the function prototype more readable.
-
-The visible parts of the returned ``struct pardevice`` are::
-
- struct pardevice {
- struct parport *port; /* Associated port */
- void *private; /* Device driver's 'handle' */
- ...
- };
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-A ``struct pardevice *``: a handle to the registered parallel port
-device that can be used for parport_claim, parport_release, etc.
-
-ERRORS
-^^^^^^
-
-A return value of NULL indicates that there was a problem registering
-a device on that port.
-
-EXAMPLE
-^^^^^^^
-
-::
-
- static int preempt (void *handle)
- {
- if (busy_right_now)
- return 1;
-
- must_reclaim_port = 1;
- return 0;
- }
-
- static void wakeup (void *handle)
- {
- struct toaster *private = handle;
- struct pardevice *dev = private->dev;
- if (!dev) return; /* avoid races */
-
- if (want_port)
- parport_claim (dev);
- }
-
- static int toaster_detect (struct toaster *private, struct parport *port)
- {
- private->dev = parport_register_device (port, "toaster", preempt,
- wakeup, NULL, 0,
- private);
- if (!private->dev)
- /* Couldn't register with parport. */
- return -EIO;
-
- must_reclaim_port = 0;
- busy_right_now = 1;
- parport_claim_or_block (private->dev);
- ...
- /* Don't need the port while the toaster warms up. */
- busy_right_now = 0;
- ...
- busy_right_now = 1;
- if (must_reclaim_port) {
- parport_claim_or_block (private->dev);
- must_reclaim_port = 0;
- }
- ...
- }
-
-SEE ALSO
-^^^^^^^^
-
-parport_unregister_device, parport_claim
-
-
-
-parport_unregister_device - finish using a port
------------------------------------------------
-
-SYNPOPSIS
-
-::
-
- #include <linux/parport.h>
-
- void parport_unregister_device (struct pardevice *dev);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-This function is the opposite of parport_register_device. After using
-parport_unregister_device, ``dev`` is no longer a valid device handle.
-
-You should not unregister a device that is currently claimed, although
-if you do it will be released automatically.
-
-EXAMPLE
-^^^^^^^
-
-::
-
- ...
- kfree (dev->private); /* before we lose the pointer */
- parport_unregister_device (dev);
- ...
-
-SEE ALSO
-^^^^^^^^
-
-
-parport_unregister_driver
-
-parport_claim, parport_claim_or_block - claim the parallel port for a device
-----------------------------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- int parport_claim (struct pardevice *dev);
- int parport_claim_or_block (struct pardevice *dev);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-These functions attempt to gain control of the parallel port on which
-``dev`` is registered. ``parport_claim`` does not block, but
-``parport_claim_or_block`` may do. (Put something here about blocking
-interruptibly or non-interruptibly.)
-
-You should not try to claim a port that you have already claimed.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-A return value of zero indicates that the port was successfully
-claimed, and the caller now has possession of the parallel port.
-
-If ``parport_claim_or_block`` blocks before returning successfully, the
-return value is positive.
-
-ERRORS
-^^^^^^
-
-========== ==========================================================
- -EAGAIN The port is unavailable at the moment, but another attempt
- to claim it may succeed.
-========== ==========================================================
-
-SEE ALSO
-^^^^^^^^
-
-
-parport_release
-
-parport_release - release the parallel port
--------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- void parport_release (struct pardevice *dev);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Once a parallel port device has been claimed, it can be released using
-``parport_release``. It cannot fail, but you should not release a
-device that you do not have possession of.
-
-EXAMPLE
-^^^^^^^
-
-::
-
- static size_t write (struct pardevice *dev, const void *buf,
- size_t len)
- {
- ...
- written = dev->port->ops->write_ecp_data (dev->port, buf,
- len);
- parport_release (dev);
- ...
- }
-
-
-SEE ALSO
-^^^^^^^^
-
-change_mode, parport_claim, parport_claim_or_block, parport_yield
-
-
-
-parport_yield, parport_yield_blocking - temporarily release a parallel port
----------------------------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- int parport_yield (struct pardevice *dev)
- int parport_yield_blocking (struct pardevice *dev);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-When a driver has control of a parallel port, it may allow another
-driver to temporarily ``borrow`` it. ``parport_yield`` does not block;
-``parport_yield_blocking`` may do.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-A return value of zero indicates that the caller still owns the port
-and the call did not block.
-
-A positive return value from ``parport_yield_blocking`` indicates that
-the caller still owns the port and the call blocked.
-
-A return value of -EAGAIN indicates that the caller no longer owns the
-port, and it must be re-claimed before use.
-
-ERRORS
-^^^^^^
-
-========= ==========================================================
- -EAGAIN Ownership of the parallel port was given away.
-========= ==========================================================
-
-SEE ALSO
-^^^^^^^^
-
-parport_release
-
-
-
-parport_wait_peripheral - wait for status lines, up to 35ms
------------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- int parport_wait_peripheral (struct parport *port,
- unsigned char mask,
- unsigned char val);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Wait for the status lines in mask to match the values in val.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-======== ==========================================================
- -EINTR a signal is pending
- 0 the status lines in mask have values in val
- 1 timed out while waiting (35ms elapsed)
-======== ==========================================================
-
-SEE ALSO
-^^^^^^^^
-
-parport_poll_peripheral
-
-
-
-parport_poll_peripheral - wait for status lines, in usec
---------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- int parport_poll_peripheral (struct parport *port,
- unsigned char mask,
- unsigned char val,
- int usec);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Wait for the status lines in mask to match the values in val.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-======== ==========================================================
- -EINTR a signal is pending
- 0 the status lines in mask have values in val
- 1 timed out while waiting (usec microseconds have elapsed)
-======== ==========================================================
-
-SEE ALSO
-^^^^^^^^
-
-parport_wait_peripheral
-
-
-
-parport_wait_event - wait for an event on a port
-------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- int parport_wait_event (struct parport *port, signed long timeout)
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Wait for an event (e.g. interrupt) on a port. The timeout is in
-jiffies.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-======= ==========================================================
- 0 success
- <0 error (exit as soon as possible)
- >0 timed out
-======= ==========================================================
-
-parport_negotiate - perform IEEE 1284 negotiation
--------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- int parport_negotiate (struct parport *, int mode);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Perform IEEE 1284 negotiation.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-======= ==========================================================
- 0 handshake OK; IEEE 1284 peripheral and mode available
- -1 handshake failed; peripheral not compliant (or none present)
- 1 handshake OK; IEEE 1284 peripheral present but mode not
- available
-======= ==========================================================
-
-SEE ALSO
-^^^^^^^^
-
-parport_read, parport_write
-
-
-
-parport_read - read data from device
-------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- ssize_t parport_read (struct parport *, void *buf, size_t len);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Read data from device in current IEEE 1284 transfer mode. This only
-works for modes that support reverse data transfer.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-If negative, an error code; otherwise the number of bytes transferred.
-
-SEE ALSO
-^^^^^^^^
-
-parport_write, parport_negotiate
-
-
-
-parport_write - write data to device
-------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- ssize_t parport_write (struct parport *, const void *buf, size_t len);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Write data to device in current IEEE 1284 transfer mode. This only
-works for modes that support forward data transfer.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-If negative, an error code; otherwise the number of bytes transferred.
-
-SEE ALSO
-^^^^^^^^
-
-parport_read, parport_negotiate
-
-
-
-parport_open - register device for particular device number
------------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct pardevice *parport_open (int devnum, const char *name,
- int (*pf) (void *),
- void (*kf) (void *),
- void (*irqf) (int, void *,
- struct pt_regs *),
- int flags, void *handle);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-This is like parport_register_device but takes a device number instead
-of a pointer to a struct parport.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-See parport_register_device. If no device is associated with devnum,
-NULL is returned.
-
-SEE ALSO
-^^^^^^^^
-
-parport_register_device
-
-
-
-parport_close - unregister device for particular device number
---------------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- void parport_close (struct pardevice *dev);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-This is the equivalent of parport_unregister_device for parport_open.
-
-SEE ALSO
-^^^^^^^^
-
-parport_unregister_device, parport_open
-
-
-
-parport_device_id - obtain IEEE 1284 Device ID
-----------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- ssize_t parport_device_id (int devnum, char *buffer, size_t len);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Obtains the IEEE 1284 Device ID associated with a given device.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-If negative, an error code; otherwise, the number of bytes of buffer
-that contain the device ID. The format of the device ID is as
-follows::
-
- [length][ID]
-
-The first two bytes indicate the inclusive length of the entire Device
-ID, and are in big-endian order. The ID is a sequence of pairs of the
-form::
-
- key:value;
-
-NOTES
-^^^^^
-
-Many devices have ill-formed IEEE 1284 Device IDs.
-
-SEE ALSO
-^^^^^^^^
-
-parport_find_class, parport_find_device
-
-
-
-parport_device_coords - convert device number to device coordinates
--------------------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- int parport_device_coords (int devnum, int *parport, int *mux,
- int *daisy);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Convert between device number (zero-based) and device coordinates
-(port, multiplexor, daisy chain address).
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-Zero on success, in which case the coordinates are (``*parport``, ``*mux``,
-``*daisy``).
-
-SEE ALSO
-^^^^^^^^
-
-parport_open, parport_device_id
-
-
-
-parport_find_class - find a device by its class
------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- typedef enum {
- PARPORT_CLASS_LEGACY = 0, /* Non-IEEE1284 device */
- PARPORT_CLASS_PRINTER,
- PARPORT_CLASS_MODEM,
- PARPORT_CLASS_NET,
- PARPORT_CLASS_HDC, /* Hard disk controller */
- PARPORT_CLASS_PCMCIA,
- PARPORT_CLASS_MEDIA, /* Multimedia device */
- PARPORT_CLASS_FDC, /* Floppy disk controller */
- PARPORT_CLASS_PORTS,
- PARPORT_CLASS_SCANNER,
- PARPORT_CLASS_DIGCAM,
- PARPORT_CLASS_OTHER, /* Anything else */
- PARPORT_CLASS_UNSPEC, /* No CLS field in ID */
- PARPORT_CLASS_SCSIADAPTER
- } parport_device_class;
-
- int parport_find_class (parport_device_class cls, int from);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Find a device by class. The search starts from device number from+1.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-The device number of the next device in that class, or -1 if no such
-device exists.
-
-NOTES
-^^^^^
-
-Example usage::
-
- int devnum = -1;
- while ((devnum = parport_find_class (PARPORT_CLASS_DIGCAM, devnum)) != -1) {
- struct pardevice *dev = parport_open (devnum, ...);
- ...
- }
-
-SEE ALSO
-^^^^^^^^
-
-parport_find_device, parport_open, parport_device_id
-
-
-
-parport_find_device - find a device by its class
-------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- int parport_find_device (const char *mfg, const char *mdl, int from);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Find a device by vendor and model. The search starts from device
-number from+1.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-The device number of the next device matching the specifications, or
--1 if no such device exists.
-
-NOTES
-^^^^^
-
-Example usage::
-
- int devnum = -1;
- while ((devnum = parport_find_device ("IOMEGA", "ZIP+", devnum)) != -1) {
- struct pardevice *dev = parport_open (devnum, ...);
- ...
- }
-
-SEE ALSO
-^^^^^^^^
-
-parport_find_class, parport_open, parport_device_id
-
-
-
-parport_set_timeout - set the inactivity timeout
-------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- long parport_set_timeout (struct pardevice *dev, long inactivity);
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Set the inactivity timeout, in jiffies, for a registered device. The
-previous timeout is returned.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-The previous timeout, in jiffies.
-
-NOTES
-^^^^^
-
-Some of the port->ops functions for a parport may take time, owing to
-delays at the peripheral. After the peripheral has not responded for
-``inactivity`` jiffies, a timeout will occur and the blocking function
-will return.
-
-A timeout of 0 jiffies is a special case: the function must do as much
-as it can without blocking or leaving the hardware in an unknown
-state. If port operations are performed from within an interrupt
-handler, for instance, a timeout of 0 jiffies should be used.
-
-Once set for a registered device, the timeout will remain at the set
-value until set again.
-
-SEE ALSO
-^^^^^^^^
-
-port->ops->xxx_read/write_yyy
-
-
-
-
-PORT FUNCTIONS
-==============
-
-The functions in the port->ops structure (struct parport_operations)
-are provided by the low-level driver responsible for that port.
-
-port->ops->read_data - read the data register
----------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- unsigned char (*read_data) (struct parport *port);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-If port->modes contains the PARPORT_MODE_TRISTATE flag and the
-PARPORT_CONTROL_DIRECTION bit in the control register is set, this
-returns the value on the data pins. If port->modes contains the
-PARPORT_MODE_TRISTATE flag and the PARPORT_CONTROL_DIRECTION bit is
-not set, the return value _may_ be the last value written to the data
-register. Otherwise the return value is undefined.
-
-SEE ALSO
-^^^^^^^^
-
-write_data, read_status, write_control
-
-
-
-port->ops->write_data - write the data register
------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- void (*write_data) (struct parport *port, unsigned char d);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Writes to the data register. May have side-effects (a STROBE pulse,
-for instance).
-
-SEE ALSO
-^^^^^^^^
-
-read_data, read_status, write_control
-
-
-
-port->ops->read_status - read the status register
--------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- unsigned char (*read_status) (struct parport *port);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Reads from the status register. This is a bitmask:
-
-- PARPORT_STATUS_ERROR (printer fault, "nFault")
-- PARPORT_STATUS_SELECT (on-line, "Select")
-- PARPORT_STATUS_PAPEROUT (no paper, "PError")
-- PARPORT_STATUS_ACK (handshake, "nAck")
-- PARPORT_STATUS_BUSY (busy, "Busy")
-
-There may be other bits set.
-
-SEE ALSO
-^^^^^^^^
-
-read_data, write_data, write_control
-
-
-
-port->ops->read_control - read the control register
----------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- unsigned char (*read_control) (struct parport *port);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Returns the last value written to the control register (either from
-write_control or frob_control). No port access is performed.
-
-SEE ALSO
-^^^^^^^^
-
-read_data, write_data, read_status, write_control
-
-
-
-port->ops->write_control - write the control register
------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- void (*write_control) (struct parport *port, unsigned char s);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Writes to the control register. This is a bitmask::
-
- _______
- - PARPORT_CONTROL_STROBE (nStrobe)
- _______
- - PARPORT_CONTROL_AUTOFD (nAutoFd)
- _____
- - PARPORT_CONTROL_INIT (nInit)
- _________
- - PARPORT_CONTROL_SELECT (nSelectIn)
-
-SEE ALSO
-^^^^^^^^
-
-read_data, write_data, read_status, frob_control
-
-
-
-port->ops->frob_control - write control register bits
------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- unsigned char (*frob_control) (struct parport *port,
- unsigned char mask,
- unsigned char val);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-This is equivalent to reading from the control register, masking out
-the bits in mask, exclusive-or'ing with the bits in val, and writing
-the result to the control register.
-
-As some ports don't allow reads from the control port, a software copy
-of its contents is maintained, so frob_control is in fact only one
-port access.
-
-SEE ALSO
-^^^^^^^^
-
-read_data, write_data, read_status, write_control
-
-
-
-port->ops->enable_irq - enable interrupt generation
----------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- void (*enable_irq) (struct parport *port);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-The parallel port hardware is instructed to generate interrupts at
-appropriate moments, although those moments are
-architecture-specific. For the PC architecture, interrupts are
-commonly generated on the rising edge of nAck.
-
-SEE ALSO
-^^^^^^^^
-
-disable_irq
-
-
-
-port->ops->disable_irq - disable interrupt generation
------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- void (*disable_irq) (struct parport *port);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-The parallel port hardware is instructed not to generate interrupts.
-The interrupt itself is not masked.
-
-SEE ALSO
-^^^^^^^^
-
-enable_irq
-
-
-
-port->ops->data_forward - enable data drivers
----------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- void (*data_forward) (struct parport *port);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Enables the data line drivers, for 8-bit host-to-peripheral
-communications.
-
-SEE ALSO
-^^^^^^^^
-
-data_reverse
-
-
-
-port->ops->data_reverse - tristate the buffer
----------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- void (*data_reverse) (struct parport *port);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Places the data bus in a high impedance state, if port->modes has the
-PARPORT_MODE_TRISTATE bit set.
-
-SEE ALSO
-^^^^^^^^
-
-data_forward
-
-
-
-port->ops->epp_write_data - write EPP data
-------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- size_t (*epp_write_data) (struct parport *port, const void *buf,
- size_t len, int flags);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Writes data in EPP mode, and returns the number of bytes written.
-
-The ``flags`` parameter may be one or more of the following,
-bitwise-or'ed together:
-
-======================= =================================================
-PARPORT_EPP_FAST Use fast transfers. Some chips provide 16-bit and
- 32-bit registers. However, if a transfer
- times out, the return value may be unreliable.
-======================= =================================================
-
-SEE ALSO
-^^^^^^^^
-
-epp_read_data, epp_write_addr, epp_read_addr
-
-
-
-port->ops->epp_read_data - read EPP data
-----------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- size_t (*epp_read_data) (struct parport *port, void *buf,
- size_t len, int flags);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Reads data in EPP mode, and returns the number of bytes read.
-
-The ``flags`` parameter may be one or more of the following,
-bitwise-or'ed together:
-
-======================= =================================================
-PARPORT_EPP_FAST Use fast transfers. Some chips provide 16-bit and
- 32-bit registers. However, if a transfer
- times out, the return value may be unreliable.
-======================= =================================================
-
-SEE ALSO
-^^^^^^^^
-
-epp_write_data, epp_write_addr, epp_read_addr
-
-
-
-port->ops->epp_write_addr - write EPP address
----------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- size_t (*epp_write_addr) (struct parport *port,
- const void *buf, size_t len, int flags);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Writes EPP addresses (8 bits each), and returns the number written.
-
-The ``flags`` parameter may be one or more of the following,
-bitwise-or'ed together:
-
-======================= =================================================
-PARPORT_EPP_FAST Use fast transfers. Some chips provide 16-bit and
- 32-bit registers. However, if a transfer
- times out, the return value may be unreliable.
-======================= =================================================
-
-(Does PARPORT_EPP_FAST make sense for this function?)
-
-SEE ALSO
-^^^^^^^^
-
-epp_write_data, epp_read_data, epp_read_addr
-
-
-
-port->ops->epp_read_addr - read EPP address
--------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- size_t (*epp_read_addr) (struct parport *port, void *buf,
- size_t len, int flags);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Reads EPP addresses (8 bits each), and returns the number read.
-
-The ``flags`` parameter may be one or more of the following,
-bitwise-or'ed together:
-
-======================= =================================================
-PARPORT_EPP_FAST Use fast transfers. Some chips provide 16-bit and
- 32-bit registers. However, if a transfer
- times out, the return value may be unreliable.
-======================= =================================================
-
-(Does PARPORT_EPP_FAST make sense for this function?)
-
-SEE ALSO
-^^^^^^^^
-
-epp_write_data, epp_read_data, epp_write_addr
-
-
-
-port->ops->ecp_write_data - write a block of ECP data
------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- size_t (*ecp_write_data) (struct parport *port,
- const void *buf, size_t len, int flags);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Writes a block of ECP data. The ``flags`` parameter is ignored.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-The number of bytes written.
-
-SEE ALSO
-^^^^^^^^
-
-ecp_read_data, ecp_write_addr
-
-
-
-port->ops->ecp_read_data - read a block of ECP data
----------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- size_t (*ecp_read_data) (struct parport *port,
- void *buf, size_t len, int flags);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Reads a block of ECP data. The ``flags`` parameter is ignored.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-The number of bytes read. NB. There may be more unread data in a
-FIFO. Is there a way of stunning the FIFO to prevent this?
-
-SEE ALSO
-^^^^^^^^
-
-ecp_write_block, ecp_write_addr
-
-
-
-port->ops->ecp_write_addr - write a block of ECP addresses
-----------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- size_t (*ecp_write_addr) (struct parport *port,
- const void *buf, size_t len, int flags);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Writes a block of ECP addresses. The ``flags`` parameter is ignored.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-The number of bytes written.
-
-NOTES
-^^^^^
-
-This may use a FIFO, and if so shall not return until the FIFO is empty.
-
-SEE ALSO
-^^^^^^^^
-
-ecp_read_data, ecp_write_data
-
-
-
-port->ops->nibble_read_data - read a block of data in nibble mode
------------------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- size_t (*nibble_read_data) (struct parport *port,
- void *buf, size_t len, int flags);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Reads a block of data in nibble mode. The ``flags`` parameter is ignored.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-The number of whole bytes read.
-
-SEE ALSO
-^^^^^^^^
-
-byte_read_data, compat_write_data
-
-
-
-port->ops->byte_read_data - read a block of data in byte mode
--------------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- size_t (*byte_read_data) (struct parport *port,
- void *buf, size_t len, int flags);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Reads a block of data in byte mode. The ``flags`` parameter is ignored.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-The number of bytes read.
-
-SEE ALSO
-^^^^^^^^
-
-nibble_read_data, compat_write_data
-
-
-
-port->ops->compat_write_data - write a block of data in compatibility mode
---------------------------------------------------------------------------
-
-SYNOPSIS
-^^^^^^^^
-
-::
-
- #include <linux/parport.h>
-
- struct parport_operations {
- ...
- size_t (*compat_write_data) (struct parport *port,
- const void *buf, size_t len, int flags);
- ...
- };
-
-DESCRIPTION
-^^^^^^^^^^^
-
-Writes a block of data in compatibility mode. The ``flags`` parameter
-is ignored.
-
-RETURN VALUE
-^^^^^^^^^^^^
-
-The number of bytes written.
-
-SEE ALSO
-^^^^^^^^
-
-nibble_read_data, byte_read_data