2
* IEEE-1284 implementation for parport.
4
* Authors: Phil Blundell <philb@gnu.org>
5
* Carsten Gross <carsten@sol.wohnheim.uni-ulm.de>
6
* Jose Renau <renau@acm.org>
7
* Tim Waugh <tim@cyberelk.demon.co.uk> (largely rewritten)
9
* This file is responsible for IEEE 1284 negotiation, and for handing
10
* read/write requests to low-level drivers.
12
* Any part of this program may be used in documents licensed under
13
* the GNU Free Documentation License, Version 1.1 or any later version
14
* published by the Free Software Foundation.
16
* Various hacks, Fred Barnes <frmb2@ukc.ac.uk>, 04/2000
19
#include <linux/module.h>
20
#include <linux/threads.h>
21
#include <linux/parport.h>
22
#include <linux/delay.h>
23
#include <linux/kernel.h>
24
#include <linux/interrupt.h>
25
#include <linux/timer.h>
26
#include <linux/sched.h>
28
#undef DEBUG /* undef me for production */
30
#ifdef CONFIG_LP_CONSOLE
31
#undef DEBUG /* Don't want a garbled console */
35
#define DPRINTK(stuff...) printk (stuff)
37
#define DPRINTK(stuff...)
40
/* Make parport_wait_peripheral wake up.
41
* It will be useful to call this from an interrupt handler. */
42
static void parport_ieee1284_wakeup (struct parport *port)
44
up (&port->physport->ieee1284.irq);
47
static struct parport *port_from_cookie[PARPORT_MAX];
48
static void timeout_waiting_on_port (unsigned long cookie)
50
parport_ieee1284_wakeup (port_from_cookie[cookie % PARPORT_MAX]);
54
* parport_wait_event - wait for an event on a parallel port
55
* @port: port to wait on
56
* @timeout: time to wait (in jiffies)
58
* This function waits for up to @timeout jiffies for an
59
* interrupt to occur on a parallel port. If the port timeout is
60
* set to zero, it returns immediately.
62
* If an interrupt occurs before the timeout period elapses, this
63
* function returns zero immediately. If it times out, it returns
64
* one. An error code less than zero indicates an error (most
65
* likely a pending signal), and the calling code should finish
66
* what it's doing as soon as it can.
69
int parport_wait_event (struct parport *port, signed long timeout)
72
struct timer_list timer;
74
if (!port->physport->cad->timeout)
75
/* Zero timeout is special, and we can't down() the
79
init_timer_on_stack(&timer);
80
timer.expires = jiffies + timeout;
81
timer.function = timeout_waiting_on_port;
82
port_from_cookie[port->number % PARPORT_MAX] = port;
83
timer.data = port->number;
86
ret = down_interruptible (&port->physport->ieee1284.irq);
87
if (!del_timer_sync(&timer) && !ret)
91
destroy_timer_on_stack(&timer);
97
* parport_poll_peripheral - poll status lines
98
* @port: port to watch
99
* @mask: status lines to watch
100
* @result: desired values of chosen status lines
103
* This function busy-waits until the masked status lines have
104
* the desired values, or until the timeout period elapses. The
105
* @mask and @result parameters are bitmasks, with the bits
106
* defined by the constants in parport.h: %PARPORT_STATUS_BUSY,
109
* This function does not call schedule(); instead it busy-waits
110
* using udelay(). It currently has a resolution of 5usec.
112
* If the status lines take on the desired values before the
113
* timeout period elapses, parport_poll_peripheral() returns zero
114
* immediately. A return value greater than zero indicates
115
* a timeout. An error code (less than zero) indicates an error,
116
* most likely a signal that arrived, and the caller should
117
* finish what it is doing as soon as possible.
120
int parport_poll_peripheral(struct parport *port,
122
unsigned char result,
125
/* Zero return code is success, >0 is timeout. */
126
int count = usec / 5 + 2;
128
unsigned char status;
129
for (i = 0; i < count; i++) {
130
status = parport_read_status (port);
131
if ((status & mask) == result)
133
if (signal_pending (current))
145
* parport_wait_peripheral - wait for status lines to change in 35ms
146
* @port: port to watch
147
* @mask: status lines to watch
148
* @result: desired values of chosen status lines
150
* This function waits until the masked status lines have the
151
* desired values, or until 35ms have elapsed (see IEEE 1284-1994
152
* page 24 to 25 for why this value in particular is hardcoded).
153
* The @mask and @result parameters are bitmasks, with the bits
154
* defined by the constants in parport.h: %PARPORT_STATUS_BUSY,
157
* The port is polled quickly to start off with, in anticipation
158
* of a fast response from the peripheral. This fast polling
159
* time is configurable (using /proc), and defaults to 500usec.
160
* If the timeout for this port (see parport_set_timeout()) is
161
* zero, the fast polling time is 35ms, and this function does
162
* not call schedule().
164
* If the timeout for this port is non-zero, after the fast
165
* polling fails it uses parport_wait_event() to wait for up to
166
* 10ms, waking up if an interrupt occurs.
169
int parport_wait_peripheral(struct parport *port,
171
unsigned char result)
175
unsigned long deadline;
176
unsigned char status;
178
usec = port->physport->spintime; /* usecs of fast polling */
179
if (!port->physport->cad->timeout)
180
/* A zero timeout is "special": busy wait for the
186
* This should be adjustable.
187
* How about making a note (in the device structure) of how long
188
* it takes, so we know for next time?
190
ret = parport_poll_peripheral (port, mask, result, usec);
194
if (!port->physport->cad->timeout)
195
/* We may be in an interrupt handler, so we can't poll
199
/* 40ms of slow polling. */
200
deadline = jiffies + msecs_to_jiffies(40);
201
while (time_before (jiffies, deadline)) {
202
if (signal_pending (current))
205
/* Wait for 10ms (or until an interrupt occurs if
206
* the handler is set) */
207
if ((ret = parport_wait_event (port, msecs_to_jiffies(10))) < 0)
210
status = parport_read_status (port);
211
if ((status & mask) == result)
215
/* parport_wait_event didn't time out, but the
216
* peripheral wasn't actually ready either.
217
* Wait for another 10ms. */
218
schedule_timeout_interruptible(msecs_to_jiffies(10));
225
#ifdef CONFIG_PARPORT_1284
226
/* Terminate a negotiated mode. */
227
static void parport_ieee1284_terminate (struct parport *port)
230
port = port->physport;
232
/* EPP terminates differently. */
233
switch (port->ieee1284.mode) {
234
case IEEE1284_MODE_EPP:
235
case IEEE1284_MODE_EPPSL:
236
case IEEE1284_MODE_EPPSWE:
237
/* Terminate from EPP mode. */
239
/* Event 68: Set nInit low */
240
parport_frob_control (port, PARPORT_CONTROL_INIT, 0);
243
/* Event 69: Set nInit high, nSelectIn low */
244
parport_frob_control (port,
245
PARPORT_CONTROL_SELECT
246
| PARPORT_CONTROL_INIT,
247
PARPORT_CONTROL_SELECT
248
| PARPORT_CONTROL_INIT);
251
case IEEE1284_MODE_ECP:
252
case IEEE1284_MODE_ECPRLE:
253
case IEEE1284_MODE_ECPSWE:
254
/* In ECP we can only terminate from fwd idle phase. */
255
if (port->ieee1284.phase != IEEE1284_PH_FWD_IDLE) {
256
/* Event 47: Set nInit high */
257
parport_frob_control (port,
259
| PARPORT_CONTROL_AUTOFD,
261
| PARPORT_CONTROL_AUTOFD);
263
/* Event 49: PError goes high */
264
r = parport_wait_peripheral (port,
265
PARPORT_STATUS_PAPEROUT,
266
PARPORT_STATUS_PAPEROUT);
268
DPRINTK (KERN_INFO "%s: Timeout at event 49\n",
271
parport_data_forward (port);
272
DPRINTK (KERN_DEBUG "%s: ECP direction: forward\n",
274
port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
280
/* Terminate from all other modes. */
282
/* Event 22: Set nSelectIn low, nAutoFd high */
283
parport_frob_control (port,
284
PARPORT_CONTROL_SELECT
285
| PARPORT_CONTROL_AUTOFD,
286
PARPORT_CONTROL_SELECT);
288
/* Event 24: nAck goes low */
289
r = parport_wait_peripheral (port, PARPORT_STATUS_ACK, 0);
291
DPRINTK (KERN_INFO "%s: Timeout at event 24\n",
294
/* Event 25: Set nAutoFd low */
295
parport_frob_control (port,
296
PARPORT_CONTROL_AUTOFD,
297
PARPORT_CONTROL_AUTOFD);
299
/* Event 27: nAck goes high */
300
r = parport_wait_peripheral (port,
304
DPRINTK (KERN_INFO "%s: Timeout at event 27\n",
307
/* Event 29: Set nAutoFd high */
308
parport_frob_control (port, PARPORT_CONTROL_AUTOFD, 0);
311
port->ieee1284.mode = IEEE1284_MODE_COMPAT;
312
port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
314
DPRINTK (KERN_DEBUG "%s: In compatibility (forward idle) mode\n",
317
#endif /* IEEE1284 support */
320
* parport_negotiate - negotiate an IEEE 1284 mode
322
* @mode: mode to negotiate to
324
* Use this to negotiate to a particular IEEE 1284 transfer mode.
325
* The @mode parameter should be one of the constants in
326
* parport.h starting %IEEE1284_MODE_xxx.
328
* The return value is 0 if the peripheral has accepted the
329
* negotiation to the mode specified, -1 if the peripheral is not
330
* IEEE 1284 compliant (or not present), or 1 if the peripheral
331
* has rejected the negotiation.
334
int parport_negotiate (struct parport *port, int mode)
336
#ifndef CONFIG_PARPORT_1284
337
if (mode == IEEE1284_MODE_COMPAT)
339
printk (KERN_ERR "parport: IEEE1284 not supported in this kernel\n");
342
int m = mode & ~IEEE1284_ADDR;
346
port = port->physport;
348
/* Is there anything to do? */
349
if (port->ieee1284.mode == mode)
352
/* Is the difference just an address-or-not bit? */
353
if ((port->ieee1284.mode & ~IEEE1284_ADDR) == (mode & ~IEEE1284_ADDR)){
354
port->ieee1284.mode = mode;
358
/* Go to compatibility forward idle mode */
359
if (port->ieee1284.mode != IEEE1284_MODE_COMPAT)
360
parport_ieee1284_terminate (port);
362
if (mode == IEEE1284_MODE_COMPAT)
363
/* Compatibility mode: no negotiation. */
367
case IEEE1284_MODE_ECPSWE:
368
m = IEEE1284_MODE_ECP;
370
case IEEE1284_MODE_EPPSL:
371
case IEEE1284_MODE_EPPSWE:
372
m = IEEE1284_MODE_EPP;
374
case IEEE1284_MODE_BECP:
375
return -ENOSYS; /* FIXME (implement BECP) */
378
if (mode & IEEE1284_EXT_LINK)
379
m = 1<<7; /* request extensibility link */
381
port->ieee1284.phase = IEEE1284_PH_NEGOTIATION;
383
/* Start off with nStrobe and nAutoFd high, and nSelectIn low */
384
parport_frob_control (port,
385
PARPORT_CONTROL_STROBE
386
| PARPORT_CONTROL_AUTOFD
387
| PARPORT_CONTROL_SELECT,
388
PARPORT_CONTROL_SELECT);
391
/* Event 0: Set data */
392
parport_data_forward (port);
393
parport_write_data (port, m);
394
udelay (400); /* Shouldn't need to wait this long. */
396
/* Event 1: Set nSelectIn high, nAutoFd low */
397
parport_frob_control (port,
398
PARPORT_CONTROL_SELECT
399
| PARPORT_CONTROL_AUTOFD,
400
PARPORT_CONTROL_AUTOFD);
402
/* Event 2: PError, Select, nFault go high, nAck goes low */
403
if (parport_wait_peripheral (port,
405
| PARPORT_STATUS_SELECT
406
| PARPORT_STATUS_PAPEROUT
407
| PARPORT_STATUS_ACK,
409
| PARPORT_STATUS_SELECT
410
| PARPORT_STATUS_PAPEROUT)) {
412
parport_frob_control (port,
413
PARPORT_CONTROL_SELECT
414
| PARPORT_CONTROL_AUTOFD,
415
PARPORT_CONTROL_SELECT);
417
"%s: Peripheral not IEEE1284 compliant (0x%02X)\n",
418
port->name, parport_read_status (port));
419
port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
420
return -1; /* Not IEEE1284 compliant */
423
/* Event 3: Set nStrobe low */
424
parport_frob_control (port,
425
PARPORT_CONTROL_STROBE,
426
PARPORT_CONTROL_STROBE);
428
/* Event 4: Set nStrobe and nAutoFd high */
430
parport_frob_control (port,
431
PARPORT_CONTROL_STROBE
432
| PARPORT_CONTROL_AUTOFD,
435
/* Event 6: nAck goes high */
436
if (parport_wait_peripheral (port,
438
PARPORT_STATUS_ACK)) {
439
/* This shouldn't really happen with a compliant device. */
441
"%s: Mode 0x%02x not supported? (0x%02x)\n",
442
port->name, mode, port->ops->read_status (port));
443
parport_ieee1284_terminate (port);
447
xflag = parport_read_status (port) & PARPORT_STATUS_SELECT;
449
/* xflag should be high for all modes other than nibble (0). */
450
if (mode && !xflag) {
451
/* Mode not supported. */
452
DPRINTK (KERN_DEBUG "%s: Mode 0x%02x rejected by peripheral\n",
454
parport_ieee1284_terminate (port);
458
/* More to do if we've requested extensibility link. */
459
if (mode & IEEE1284_EXT_LINK) {
462
parport_write_data (port, m);
465
/* Event 51: Set nStrobe low */
466
parport_frob_control (port,
467
PARPORT_CONTROL_STROBE,
468
PARPORT_CONTROL_STROBE);
470
/* Event 52: nAck goes low */
471
if (parport_wait_peripheral (port, PARPORT_STATUS_ACK, 0)) {
472
/* This peripheral is _very_ slow. */
474
"%s: Event 52 didn't happen\n",
476
parport_ieee1284_terminate (port);
480
/* Event 53: Set nStrobe high */
481
parport_frob_control (port,
482
PARPORT_CONTROL_STROBE,
485
/* Event 55: nAck goes high */
486
if (parport_wait_peripheral (port,
488
PARPORT_STATUS_ACK)) {
489
/* This shouldn't really happen with a compliant
492
"%s: Mode 0x%02x not supported? (0x%02x)\n",
494
port->ops->read_status (port));
495
parport_ieee1284_terminate (port);
499
/* Event 54: Peripheral sets XFlag to reflect support */
500
xflag = parport_read_status (port) & PARPORT_STATUS_SELECT;
502
/* xflag should be high. */
504
/* Extended mode not supported. */
505
DPRINTK (KERN_DEBUG "%s: Extended mode 0x%02x not "
506
"supported\n", port->name, mode);
507
parport_ieee1284_terminate (port);
511
/* Any further setup is left to the caller. */
514
/* Mode is supported */
515
DPRINTK (KERN_DEBUG "%s: In mode 0x%02x\n", port->name, mode);
516
port->ieee1284.mode = mode;
518
/* But ECP is special */
519
if (!(mode & IEEE1284_EXT_LINK) && (m & IEEE1284_MODE_ECP)) {
520
port->ieee1284.phase = IEEE1284_PH_ECP_SETUP;
522
/* Event 30: Set nAutoFd low */
523
parport_frob_control (port,
524
PARPORT_CONTROL_AUTOFD,
525
PARPORT_CONTROL_AUTOFD);
527
/* Event 31: PError goes high. */
528
r = parport_wait_peripheral (port,
529
PARPORT_STATUS_PAPEROUT,
530
PARPORT_STATUS_PAPEROUT);
532
DPRINTK (KERN_INFO "%s: Timeout at event 31\n",
536
port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
537
DPRINTK (KERN_DEBUG "%s: ECP direction: forward\n",
539
} else switch (mode) {
540
case IEEE1284_MODE_NIBBLE:
541
case IEEE1284_MODE_BYTE:
542
port->ieee1284.phase = IEEE1284_PH_REV_IDLE;
545
port->ieee1284.phase = IEEE1284_PH_FWD_IDLE;
550
#endif /* IEEE1284 support */
553
/* Acknowledge that the peripheral has data available.
554
* Events 18-20, in order to get from Reverse Idle phase
555
* to Host Busy Data Available.
556
* This will most likely be called from an interrupt.
557
* Returns zero if data was available.
559
#ifdef CONFIG_PARPORT_1284
560
static int parport_ieee1284_ack_data_avail (struct parport *port)
562
if (parport_read_status (port) & PARPORT_STATUS_ERROR)
563
/* Event 18 didn't happen. */
566
/* Event 20: nAutoFd goes high. */
567
port->ops->frob_control (port, PARPORT_CONTROL_AUTOFD, 0);
568
port->ieee1284.phase = IEEE1284_PH_HBUSY_DAVAIL;
571
#endif /* IEEE1284 support */
573
/* Handle an interrupt. */
574
void parport_ieee1284_interrupt (void *handle)
576
struct parport *port = handle;
577
parport_ieee1284_wakeup (port);
579
#ifdef CONFIG_PARPORT_1284
580
if (port->ieee1284.phase == IEEE1284_PH_REV_IDLE) {
581
/* An interrupt in this phase means that data
582
* is now available. */
583
DPRINTK (KERN_DEBUG "%s: Data available\n", port->name);
584
parport_ieee1284_ack_data_avail (port);
586
#endif /* IEEE1284 support */
590
* parport_write - write a block of data to a parallel port
591
* @port: port to write to
592
* @buffer: data buffer (in kernel space)
593
* @len: number of bytes of data to transfer
595
* This will write up to @len bytes of @buffer to the port
596
* specified, using the IEEE 1284 transfer mode most recently
597
* negotiated to (using parport_negotiate()), as long as that
598
* mode supports forward transfers (host to peripheral).
600
* It is the caller's responsibility to ensure that the first
601
* @len bytes of @buffer are valid.
603
* This function returns the number of bytes transferred (if zero
604
* or positive), or else an error code.
607
ssize_t parport_write (struct parport *port, const void *buffer, size_t len)
609
#ifndef CONFIG_PARPORT_1284
610
return port->ops->compat_write_data (port, buffer, len, 0);
613
int mode = port->ieee1284.mode;
614
int addr = mode & IEEE1284_ADDR;
615
size_t (*fn) (struct parport *, const void *, size_t, int);
617
/* Ignore the device-ID-request bit and the address bit. */
618
mode &= ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
620
/* Use the mode we're in. */
622
case IEEE1284_MODE_NIBBLE:
623
case IEEE1284_MODE_BYTE:
624
parport_negotiate (port, IEEE1284_MODE_COMPAT);
625
case IEEE1284_MODE_COMPAT:
626
DPRINTK (KERN_DEBUG "%s: Using compatibility mode\n",
628
fn = port->ops->compat_write_data;
631
case IEEE1284_MODE_EPP:
632
DPRINTK (KERN_DEBUG "%s: Using EPP mode\n", port->name);
634
fn = port->ops->epp_write_addr;
636
fn = port->ops->epp_write_data;
639
case IEEE1284_MODE_EPPSWE:
640
DPRINTK (KERN_DEBUG "%s: Using software-emulated EPP mode\n",
643
fn = parport_ieee1284_epp_write_addr;
645
fn = parport_ieee1284_epp_write_data;
648
case IEEE1284_MODE_ECP:
649
case IEEE1284_MODE_ECPRLE:
650
DPRINTK (KERN_DEBUG "%s: Using ECP mode\n", port->name);
652
fn = port->ops->ecp_write_addr;
654
fn = port->ops->ecp_write_data;
658
case IEEE1284_MODE_ECPSWE:
659
DPRINTK (KERN_DEBUG "%s: Using software-emulated ECP mode\n",
661
/* The caller has specified that it must be emulated,
662
* even if we have ECP hardware! */
664
fn = parport_ieee1284_ecp_write_addr;
666
fn = parport_ieee1284_ecp_write_data;
671
DPRINTK (KERN_DEBUG "%s: Unknown mode 0x%02x\n", port->name,
672
port->ieee1284.mode);
676
retval = (*fn) (port, buffer, len, 0);
677
DPRINTK (KERN_DEBUG "%s: wrote %d/%d bytes\n", port->name, retval, len);
679
#endif /* IEEE1284 support */
683
* parport_read - read a block of data from a parallel port
684
* @port: port to read from
685
* @buffer: data buffer (in kernel space)
686
* @len: number of bytes of data to transfer
688
* This will read up to @len bytes of @buffer to the port
689
* specified, using the IEEE 1284 transfer mode most recently
690
* negotiated to (using parport_negotiate()), as long as that
691
* mode supports reverse transfers (peripheral to host).
693
* It is the caller's responsibility to ensure that the first
694
* @len bytes of @buffer are available to write to.
696
* This function returns the number of bytes transferred (if zero
697
* or positive), or else an error code.
700
ssize_t parport_read (struct parport *port, void *buffer, size_t len)
702
#ifndef CONFIG_PARPORT_1284
703
printk (KERN_ERR "parport: IEEE1284 not supported in this kernel\n");
706
int mode = port->physport->ieee1284.mode;
707
int addr = mode & IEEE1284_ADDR;
708
size_t (*fn) (struct parport *, void *, size_t, int);
710
/* Ignore the device-ID-request bit and the address bit. */
711
mode &= ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
713
/* Use the mode we're in. */
715
case IEEE1284_MODE_COMPAT:
716
/* if we can tri-state use BYTE mode instead of NIBBLE mode,
717
* if that fails, revert to NIBBLE mode -- ought to store somewhere
718
* the device's ability to do BYTE mode reverse transfers, so we don't
719
* end up needlessly calling negotiate(BYTE) repeately.. (fb)
721
if ((port->physport->modes & PARPORT_MODE_TRISTATE) &&
722
!parport_negotiate (port, IEEE1284_MODE_BYTE)) {
723
/* got into BYTE mode OK */
724
DPRINTK (KERN_DEBUG "%s: Using byte mode\n", port->name);
725
fn = port->ops->byte_read_data;
728
if (parport_negotiate (port, IEEE1284_MODE_NIBBLE)) {
731
/* fall through to NIBBLE */
732
case IEEE1284_MODE_NIBBLE:
733
DPRINTK (KERN_DEBUG "%s: Using nibble mode\n", port->name);
734
fn = port->ops->nibble_read_data;
737
case IEEE1284_MODE_BYTE:
738
DPRINTK (KERN_DEBUG "%s: Using byte mode\n", port->name);
739
fn = port->ops->byte_read_data;
742
case IEEE1284_MODE_EPP:
743
DPRINTK (KERN_DEBUG "%s: Using EPP mode\n", port->name);
745
fn = port->ops->epp_read_addr;
747
fn = port->ops->epp_read_data;
750
case IEEE1284_MODE_EPPSWE:
751
DPRINTK (KERN_DEBUG "%s: Using software-emulated EPP mode\n",
754
fn = parport_ieee1284_epp_read_addr;
756
fn = parport_ieee1284_epp_read_data;
759
case IEEE1284_MODE_ECP:
760
case IEEE1284_MODE_ECPRLE:
761
DPRINTK (KERN_DEBUG "%s: Using ECP mode\n", port->name);
762
fn = port->ops->ecp_read_data;
765
case IEEE1284_MODE_ECPSWE:
766
DPRINTK (KERN_DEBUG "%s: Using software-emulated ECP mode\n",
768
fn = parport_ieee1284_ecp_read_data;
772
DPRINTK (KERN_DEBUG "%s: Unknown mode 0x%02x\n", port->name,
773
port->physport->ieee1284.mode);
777
return (*fn) (port, buffer, len, 0);
778
#endif /* IEEE1284 support */
782
* parport_set_timeout - set the inactivity timeout for a device
783
* @dev: device on a port
784
* @inactivity: inactivity timeout (in jiffies)
786
* This sets the inactivity timeout for a particular device on a
787
* port. This affects functions like parport_wait_peripheral().
788
* The special value 0 means not to call schedule() while dealing
791
* The return value is the previous inactivity timeout.
793
* Any callers of parport_wait_event() for this device are woken
797
long parport_set_timeout (struct pardevice *dev, long inactivity)
799
long int old = dev->timeout;
801
dev->timeout = inactivity;
803
if (dev->port->physport->cad == dev)
804
parport_ieee1284_wakeup (dev->port);
809
/* Exported symbols for modules. */
811
EXPORT_SYMBOL(parport_negotiate);
812
EXPORT_SYMBOL(parport_write);
813
EXPORT_SYMBOL(parport_read);
814
EXPORT_SYMBOL(parport_wait_peripheral);
815
EXPORT_SYMBOL(parport_wait_event);
816
EXPORT_SYMBOL(parport_set_timeout);
817
EXPORT_SYMBOL(parport_ieee1284_interrupt);