aboutsummaryrefslogtreecommitdiff
path: root/drivers/char/lp.c
blob: e444c2dba160870658b8ac45910ba79b85d12419 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
/*
 * Generic parallel printer driver
 *
 * Copyright (C) 1992 by Jim Weigand and Linus Torvalds
 * Copyright (C) 1992,1993 by Michael K. Johnson
 * - Thanks much to Gunter Windau for pointing out to me where the error
 *   checking ought to be.
 * Copyright (C) 1993 by Nigel Gamble (added interrupt code)
 * Copyright (C) 1994 by Alan Cox (Modularised it)
 * LPCAREFUL, LPABORT, LPGETSTATUS added by Chris Metcalf, metcalf@lcs.mit.edu
 * Statistics and support for slow printers by Rob Janssen, rob@knoware.nl
 * "lp=" command line parameters added by Grant Guenther, grant@torque.net
 * lp_read (Status readback) support added by Carsten Gross,
 *                                             carsten@sol.wohnheim.uni-ulm.de
 * Support for parport by Philip Blundell <philb@gnu.org>
 * Parport sharing hacking by Andrea Arcangeli
 * Fixed kernel_(to/from)_user memory copy to check for errors
 * 				by Riccardo Facchetti <fizban@tin.it>
 * 22-JAN-1998  Added support for devfs  Richard Gooch <rgooch@atnf.csiro.au>
 * Redesigned interrupt handling for handle printers with buggy handshake
 *				by Andrea Arcangeli, 11 May 1998
 * Full efficient handling of printer with buggy irq handshake (now I have
 * understood the meaning of the strange handshake). This is done sending new
 * characters if the interrupt is just happened, even if the printer say to
 * be still BUSY. This is needed at least with Epson Stylus Color. To enable
 * the new TRUST_IRQ mode read the `LP OPTIMIZATION' section below...
 * Fixed the irq on the rising edge of the strobe case.
 * Obsoleted the CAREFUL flag since a printer that doesn' t work with
 * CAREFUL will block a bit after in lp_check_status().
 *				Andrea Arcangeli, 15 Oct 1998
 * Obsoleted and removed all the lowlevel stuff implemented in the last
 * month to use the IEEE1284 functions (that handle the _new_ compatibilty
 * mode fine).
 */

/* This driver should, in theory, work with any parallel port that has an
 * appropriate low-level driver; all I/O is done through the parport
 * abstraction layer.
 *
 * If this driver is built into the kernel, you can configure it using the
 * kernel command-line.  For example:
 *
 *	lp=parport1,none,parport2	(bind lp0 to parport1, disable lp1 and
 *					 bind lp2 to parport2)
 *
 *	lp=auto				(assign lp devices to all ports that
 *				         have printers attached, as determined
 *					 by the IEEE-1284 autoprobe)
 * 
 *	lp=reset			(reset the printer during 
 *					 initialisation)
 *
 *	lp=off				(disable the printer driver entirely)
 *
 * If the driver is loaded as a module, similar functionality is available
 * using module parameters.  The equivalent of the above commands would be:
 *
 *	# insmod lp.o parport=1,none,2
 *
 *	# insmod lp.o parport=auto
 *
 *	# insmod lp.o reset=1
 */

/* COMPATIBILITY WITH OLD KERNELS
 *
 * Under Linux 2.0 and previous versions, lp devices were bound to ports at
 * particular I/O addresses, as follows:
 *
 *	lp0		0x3bc
 *	lp1		0x378
 *	lp2		0x278
 *
 * The new driver, by default, binds lp devices to parport devices as it
 * finds them.  This means that if you only have one port, it will be bound
 * to lp0 regardless of its I/O address.  If you need the old behaviour, you
 * can force it using the parameters described above.
 */

/*
 * The new interrupt handling code take care of the buggy handshake
 * of some HP and Epson printer:
 * ___
 * ACK    _______________    ___________
 *                       |__|
 * ____
 * BUSY   _________              _______
 *                 |____________|
 *
 * I discovered this using the printer scanner that you can find at:
 *
 *	ftp://e-mind.com/pub/linux/pscan/
 *
 *					11 May 98, Andrea Arcangeli
 *
 * My printer scanner run on an Epson Stylus Color show that such printer
 * generates the irq on the _rising_ edge of the STROBE. Now lp handle
 * this case fine too.
 *
 *					15 Oct 1998, Andrea Arcangeli
 *
 * The so called `buggy' handshake is really the well documented
 * compatibility mode IEEE1284 handshake. They changed the well known
 * Centronics handshake acking in the middle of busy expecting to not
 * break drivers or legacy application, while they broken linux lp
 * until I fixed it reverse engineering the protocol by hand some
 * month ago...
 *
 *                                     14 Dec 1998, Andrea Arcangeli
 *
 * Copyright (C) 2000 by Tim Waugh (added LPSETTIMEOUT ioctl)
 */

#include <linux/module.h>
#include <linux/init.h>

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fcntl.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <linux/console.h>
#include <linux/device.h>
#include <linux/wait.h>
#include <linux/jiffies.h>
#include <linux/smp_lock.h>

#include <linux/parport.h>
#undef LP_STATS
#include <linux/lp.h>

#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/system.h>

/* if you have more than 8 printers, remember to increase LP_NO */
#define LP_NO 8

static struct lp_struct lp_table[LP_NO];

static unsigned int lp_count = 0;
static struct class *lp_class;

#ifdef CONFIG_LP_CONSOLE
static struct parport *console_registered;
#endif /* CONFIG_LP_CONSOLE */

#undef LP_DEBUG

/* Bits used to manage claiming the parport device */
#define LP_PREEMPT_REQUEST 1
#define LP_PARPORT_CLAIMED 2

/* --- low-level port access ----------------------------------- */

#define r_dtr(x)	(parport_read_data(lp_table[(x)].dev->port))
#define r_str(x)	(parport_read_status(lp_table[(x)].dev->port))
#define w_ctr(x,y)	do { parport_write_control(lp_table[(x)].dev->port, (y)); } while (0)
#define w_dtr(x,y)	do { parport_write_data(lp_table[(x)].dev->port, (y)); } while (0)

/* Claim the parport or block trying unless we've already claimed it */
static void lp_claim_parport_or_block(struct lp_struct *this_lp)
{
	if (!test_and_set_bit(LP_PARPORT_CLAIMED, &this_lp->bits)) {
		parport_claim_or_block (this_lp->dev);
	}
}

/* Claim the parport or block trying unless we've already claimed it */
static void lp_release_parport(struct lp_struct *this_lp)
{
	if (test_and_clear_bit(LP_PARPORT_CLAIMED, &this_lp->bits)) {
		parport_release (this_lp->dev);
	}
}



static int lp_preempt(void *handle)
{
	struct lp_struct *this_lp = (struct lp_struct *)handle;
	set_bit(LP_PREEMPT_REQUEST, &this_lp->bits);
	return (1);
}


/* 
 * Try to negotiate to a new mode; if unsuccessful negotiate to
 * compatibility mode.  Return the mode we ended up in.
 */
static int lp_negotiate(struct parport * port, int mode)
{
	if (parport_negotiate (port, mode) != 0) {
		mode = IEEE1284_MODE_COMPAT;
		parport_negotiate (port, mode);
	}

	return (mode);
}

static int lp_reset(int minor)
{
	int retval;
	lp_claim_parport_or_block (&lp_table[minor]);
	w_ctr(minor, LP_PSELECP);
	udelay (LP_DELAY);
	w_ctr(minor, LP_PSELECP | LP_PINITP);
	retval = r_str(minor);
	lp_release_parport (&lp_table[minor]);
	return retval;
}

static void lp_error (int minor)
{
	DEFINE_WAIT(wait);
	int polling;

	if (LP_F(minor) & LP_ABORT)
		return;

	polling = lp_table[minor].dev->port->irq == PARPORT_IRQ_NONE;
	if (polling) lp_release_parport (&lp_table[minor]);
	prepare_to_wait(&lp_table[minor].waitq, &wait, TASK_INTERRUPTIBLE);
	schedule_timeout(LP_TIMEOUT_POLLED);
	finish_wait(&lp_table[minor].waitq, &wait);
	if (polling) lp_claim_parport_or_block (&lp_table[minor]);
	else parport_yield_blocking (lp_table[minor].dev);
}

static int lp_check_status(int minor)
{
	int error = 0;
	unsigned int last = lp_table[minor].last_error;
	unsigned char status = r_str(minor);
	if ((status & LP_PERRORP) && !(LP_F(minor) & LP_CAREFUL))
		/* No error. */
		last = 0;
	else if ((status & LP_POUTPA)) {
		if (last != LP_POUTPA) {
			last = LP_POUTPA;
			printk(KERN_INFO "lp%d out of paper\n", minor);
		}
		error = -ENOSPC;
	} else if (!(status & LP_PSELECD)) {
		if (last != LP_PSELECD) {
			last = LP_PSELECD;
			printk(KERN_INFO "lp%d off-line\n", minor);
		}
		error = -EIO;
	} else if (!(status & LP_PERRORP)) {
		if (last != LP_PERRORP) {
			last = LP_PERRORP;
			printk(KERN_INFO "lp%d on fire\n", minor);
		}
		error = -EIO;
	} else {
		last = 0; /* Come here if LP_CAREFUL is set and no
                             errors are reported. */
	}

	lp_table[minor].last_error = last;

	if (last != 0)
		lp_error(minor);

	return error;
}

static int lp_wait_ready(int minor, int nonblock)
{
	int error = 0;

	/* If we're not in compatibility mode, we're ready now! */
	if (lp_table[minor].current_mode != IEEE1284_MODE_COMPAT) {
	  return (0);
	}

	do {
		error = lp_check_status (minor);
		if (error && (nonblock || (LP_F(minor) & LP_ABORT)))
			break;
		if (signal_pending (current)) {
			error = -EINTR;
			break;
		}
	} while (error);
	return error;
}

static ssize_t lp_write(struct file * file, const char __user * buf,
		        size_t count, loff_t *ppos)
{
	unsigned int minor = iminor(file->f_path.dentry->d_inode);
	struct parport *port = lp_table[minor].dev->port;
	char *kbuf = lp_table[minor].lp_buffer;
	ssize_t retv = 0;
	ssize_t written;
	size_t copy_size = count;
	int nonblock = ((file->f_flags & O_NONBLOCK) ||
			(LP_F(minor) & LP_ABORT));

#ifdef LP_STATS
	if (time_after(jiffies, lp_table[minor].lastcall + LP_TIME(minor)))
		lp_table[minor].runchars = 0;

	lp_table[minor].lastcall = jiffies;
#endif

	/* Need to copy the data from user-space. */
	if (copy_size > LP_BUFFER_SIZE)
		copy_size = LP_BUFFER_SIZE;

	if (mutex_lock_interruptible(&lp_table[minor].port_mutex))
		return -EINTR;

	if (copy_from_user (kbuf, buf, copy_size)) {
		retv = -EFAULT;
		goto out_unlock;
	}

 	/* Claim Parport or sleep until it becomes available
 	 */
	lp_claim_parport_or_block (&lp_table[minor]);
	/* Go to the proper mode. */
	lp_table[minor].current_mode = lp_negotiate (port, 
						     lp_table[minor].best_mode);

	parport_set_timeout (lp_table[minor].dev,
			     (nonblock ? PARPORT_INACTIVITY_O_NONBLOCK
			      : lp_table[minor].timeout));

	if ((retv = lp_wait_ready (minor, nonblock)) == 0)
	do {
		/* Write the data. */
		written = parport_write (port, kbuf, copy_size);
		if (written > 0) {
			copy_size -= written;
			count -= written;
			buf  += written;
			retv += written;
		}

		if (signal_pending (current)) {
			if (retv == 0)
				retv = -EINTR;

			break;
		}

		if (copy_size > 0) {
			/* incomplete write -> check error ! */
			int error;

			parport_negotiate (lp_table[minor].dev->port, 
					   IEEE1284_MODE_COMPAT);
			lp_table[minor].current_mode = IEEE1284_MODE_COMPAT;

			error = lp_wait_ready (minor, nonblock);

			if (error) {
				if (retv == 0)
					retv = error;
				break;
			} else if (nonblock) {
				if (retv == 0)
					retv = -EAGAIN;
				break;
			}

			parport_yield_blocking (lp_table[minor].dev);
			lp_table[minor].current_mode 
			  = lp_negotiate (port, 
					  lp_table[minor].best_mode);

		} else if (need_resched())
			schedule ();

		if (count) {
			copy_size = count;
			if (copy_size > LP_BUFFER_SIZE)
				copy_size = LP_BUFFER_SIZE;

			if (copy_from_user(kbuf, buf, copy_size)) {
				if (retv == 0)
					retv = -EFAULT;
				break;
			}
		}	
	} while (count > 0);

	if (test_and_clear_bit(LP_PREEMPT_REQUEST, 
			       &lp_table[minor].bits)) {
		printk(KERN_INFO "lp%d releasing parport\n", minor);
		parport_negotiate (lp_table[minor].dev->port, 
				   IEEE1284_MODE_COMPAT);
		lp_table[minor].current_mode = IEEE1284_MODE_COMPAT;
		lp_release_parport (&lp_table[minor]);
	}
out_unlock:
	mutex_unlock(&lp_table[minor].port_mutex);

 	return retv;
}

#ifdef CONFIG_PARPORT_1284

/* Status readback conforming to ieee1284 */
static ssize_t lp_read(struct file * file, char __user * buf,
		       size_t count, loff_t *ppos)
{
	DEFINE_WAIT(wait);
	unsigned int minor=iminor(file->f_path.dentry->d_inode);
	struct parport *port = lp_table[minor].dev->port;
	ssize_t retval = 0;
	char *kbuf = lp_table[minor].lp_buffer;
	int nonblock = ((file->f_flags & O_NONBLOCK) ||
			(LP_F(minor) & LP_ABORT));

	if (count > LP_BUFFER_SIZE)
		count = LP_BUFFER_SIZE;

	if (mutex_lock_interruptible(&lp_table[minor].port_mutex))
		return -EINTR;

	lp_claim_parport_or_block (&lp_table[minor]);

	parport_set_timeout (lp_table[minor].dev,
			     (nonblock ? PARPORT_INACTIVITY_O_NONBLOCK
			      : lp_table[minor].timeout));

	parport_negotiate (lp_table[minor].dev->port, IEEE1284_MODE_COMPAT);
	if (parport_negotiate (lp_table[minor].dev->port,
			       IEEE1284_MODE_NIBBLE)) {
		retval = -EIO;
		goto out;
	}

	while (retval == 0) {
		retval = parport_read (port, kbuf, count);

		if (retval > 0)
			break;

		if (nonblock) {
			retval = -EAGAIN;
			break;
		}

		/* Wait for data. */

		if (lp_table[minor].dev->port->irq == PARPORT_IRQ_NONE) {
			parport_negotiate (lp_table[minor].dev->port,
					   IEEE1284_MODE_COMPAT);
			lp_error (minor);
			if (parport_negotiate (lp_table[minor].dev->port,
					       IEEE1284_MODE_NIBBLE)) {
				retval = -EIO;
				goto out;
			}
		} else {
			prepare_to_wait(&lp_table[minor].waitq, &wait, TASK_INTERRUPTIBLE);
			schedule_timeout(LP_TIMEOUT_POLLED);
			finish_wait(&lp_table[minor].waitq, &wait);
		}

		if (signal_pending (current)) {
			retval = -ERESTARTSYS;
			break;
		}

		cond_resched ();
	}
	parport_negotiate (lp_table[minor].dev->port, IEEE1284_MODE_COMPAT);
 out:
	lp_release_parport (&lp_table[minor]);

	if (retval > 0 && copy_to_user (buf, kbuf, retval))
		retval = -EFAULT;

	mutex_unlock(&lp_table[minor].port_mutex);

	return retval;
}

#endif /* IEEE 1284 support */

static int lp_open(struct inode * inode, struct file * file)
{
	unsigned int minor = iminor(inode);
	int ret = 0;

	lock_kernel();
	if (minor >= LP_NO) {
		ret = -ENXIO;
		goto out;
	}
	if ((LP_F(minor) & LP_EXIST) == 0) {
		ret = -ENXIO;
		goto out;
	}
	if (test_and_set_bit(LP_BUSY_BIT_POS, &LP_F(minor))) {
		ret = -EBUSY;
		goto out;
	}
	/* If ABORTOPEN is set and the printer is offline or out of paper,
	   we may still want to open it to perform ioctl()s.  Therefore we
	   have commandeered O_NONBLOCK, even though it is being used in
	   a non-standard manner.  This is strictly a Linux hack, and
	   should most likely only ever be used by the tunelp application. */
	if ((LP_F(minor) & LP_ABORTOPEN) && !(file->f_flags & O_NONBLOCK)) {
		int status;
		lp_claim_parport_or_block (&lp_table[minor]);
		status = r_str(minor);
		lp_release_parport (&lp_table[minor]);
		if (status & LP_POUTPA) {
			printk(KERN_INFO "lp%d out of paper\n", minor);
			LP_F(minor) &= ~LP_BUSY;
			ret = -ENOSPC;
			goto out;
		} else if (!(status & LP_PSELECD)) {
			printk(KERN_INFO "lp%d off-line\n", minor);
			LP_F(minor) &= ~LP_BUSY;
			ret = -EIO;
			goto out;
		} else if (!(status & LP_PERRORP)) {
			printk(KERN_ERR "lp%d printer error\n", minor);
			LP_F(minor) &= ~LP_BUSY;
			ret = -EIO;
			goto out;
		}
	}
	lp_table[minor].lp_buffer = kmalloc(LP_BUFFER_SIZE, GFP_KERNEL);
	if (!lp_table[minor].lp_buffer) {
		LP_F(minor) &= ~LP_BUSY;
		ret = -ENOMEM;
		goto out;
	}
	/* Determine if the peripheral supports ECP mode */
	lp_claim_parport_or_block (&lp_table[minor]);
	if ( (lp_table[minor].dev->port->modes & PARPORT_MODE_ECP) &&
             !parport_negotiate (lp_table[minor].dev->port, 
                                 IEEE1284_MODE_ECP)) {
		printk (KERN_INFO "lp%d: ECP mode\n", minor);
		lp_table[minor].best_mode = IEEE1284_MODE_ECP;
	} else {
		lp_table[minor].best_mode = IEEE1284_MODE_COMPAT;
	}
	/* Leave peripheral in compatibility mode */
	parport_negotiate (lp_table[minor].dev->port, IEEE1284_MODE_COMPAT);
	lp_release_parport (&lp_table[minor]);
	lp_table[minor].current_mode = IEEE1284_MODE_COMPAT;
out:
	unlock_kernel();
	return ret;
}

static int lp_release(struct inode * inode, struct file * file)
{
	unsigned int minor = iminor(inode);

	lp_claim_parport_or_block (&lp_table[minor]);
	parport_negotiate (lp_table[minor].dev->port, IEEE1284_MODE_COMPAT);
	lp_table[minor].current_mode = IEEE1284_MODE_COMPAT;
	lp_release_parport (&lp_table[minor]);
	kfree(lp_table[minor].lp_buffer);
	lp_table[minor].lp_buffer = NULL;
	LP_F(minor) &= ~LP_BUSY;
	return 0;
}

static int lp_ioctl(struct inode *inode, struct file *file,
		    unsigned int cmd, unsigned long arg)
{
	unsigned int minor = iminor(inode);
	int status;
	int retval = 0;
	void __user *argp = (void __user *)arg;

#ifdef LP_DEBUG
	printk(KERN_DEBUG "lp%d ioctl, cmd: 0x%x, arg: 0x%lx\n", minor, cmd, arg);
#endif
	if (minor >= LP_NO)
		return -ENODEV;
	if ((LP_F(minor) & LP_EXIST) == 0)
		return -ENODEV;
	switch ( cmd ) {
		struct timeval par_timeout;
		long to_jiffies;

		case LPTIME:
			LP_TIME(minor) = arg * HZ/100;
			break;
		case LPCHAR:
			LP_CHAR(minor) = arg;
			break;
		case LPABORT:
			if (arg)
				LP_F(minor) |= LP_ABORT;
			else
				LP_F(minor) &= ~LP_ABORT;
			break;
		case LPABORTOPEN:
			if (arg)
				LP_F(minor) |= LP_ABORTOPEN;
			else
				LP_F(minor) &= ~LP_ABORTOPEN;
			break;
		case LPCAREFUL:
			if (arg)
				LP_F(minor) |= LP_CAREFUL;
			else
				LP_F(minor) &= ~LP_CAREFUL;
			break;
		case LPWAIT:
			LP_WAIT(minor) = arg;
			break;
		case LPSETIRQ: 
			return -EINVAL;
			break;
		case LPGETIRQ:
			if (copy_to_user(argp, &LP_IRQ(minor),
					sizeof(int)))
				return -EFAULT;
			break;
		case LPGETSTATUS:
			lp_claim_parport_or_block (&lp_table[minor]);
			status = r_str(minor);
			lp_release_parport (&lp_table[minor]);

			if (copy_to_user(argp, &status, sizeof(int)))
				return -EFAULT;
			break;
		case LPRESET:
			lp_reset(minor);
			break;
#ifdef LP_STATS
		case LPGETSTATS:
			if (copy_to_user(argp, &LP_STAT(minor),
					sizeof(struct lp_stats)))
				return -EFAULT;
			if (capable(CAP_SYS_ADMIN))
				memset(&LP_STAT(minor), 0,
						sizeof(struct lp_stats));
			break;
#endif
 		case LPGETFLAGS:
 			status = LP_F(minor);
			if (copy_to_user(argp, &status, sizeof(int)))
				return -EFAULT;
			break;

		case LPSETTIMEOUT:
			if (copy_from_user (&par_timeout, argp,
					    sizeof (struct timeval))) {
				return -EFAULT;
			}
			/* Convert to jiffies, place in lp_table */
			if ((par_timeout.tv_sec < 0) ||
			    (par_timeout.tv_usec < 0)) {
				return -EINVAL;
			}
			to_jiffies = DIV_ROUND_UP(par_timeout.tv_usec, 1000000/HZ);
			to_jiffies += par_timeout.tv_sec * (long) HZ;
			if (to_jiffies <= 0) {
				return -EINVAL;
			}
			lp_table[minor].timeout = to_jiffies;
			break;

		default:
			retval = -EINVAL;
	}
	return retval;
}

static const struct file_operations lp_fops = {
	.owner		= THIS_MODULE,
	.write		= lp_write,
	.ioctl		= lp_ioctl,
	.open		= lp_open,
	.release	= lp_release,
#ifdef CONFIG_PARPORT_1284
	.read		= lp_read,
#endif
};

/* --- support for console on the line printer ----------------- */

#ifdef CONFIG_LP_CONSOLE

#define CONSOLE_LP 0

/* If the printer is out of paper, we can either lose the messages or
 * stall until the printer is happy again.  Define CONSOLE_LP_STRICT
 * non-zero to get the latter behaviour. */
#define CONSOLE_LP_STRICT 1

/* The console must be locked when we get here. */

static void lp_console_write (struct console *co, const char *s,
			      unsigned count)
{
	struct pardevice *dev = lp_table[CONSOLE_LP].dev;
	struct parport *port = dev->port;
	ssize_t written;

	if (parport_claim (dev))
		/* Nothing we can do. */
		return;

	parport_set_timeout (dev, 0);

	/* Go to compatibility mode. */
	parport_negotiate (port, IEEE1284_MODE_COMPAT);

	do {
		/* Write the data, converting LF->CRLF as we go. */
		ssize_t canwrite = count;
		char *lf = memchr (s, '\n', count);
		if (lf)
			canwrite = lf - s;

		if (canwrite > 0) {
			written = parport_write (port, s, canwrite);

			if (written <= 0)
				continue;

			s += written;
			count -= written;
			canwrite -= written;
		}

		if (lf && canwrite <= 0) {
			const char *crlf = "\r\n";
			int i = 2;

			/* Dodge the original '\n', and put '\r\n' instead. */
			s++;
			count--;
			do {
				written = parport_write (port, crlf, i);
				if (written > 0)
					i -= written, crlf += written;
			} while (i > 0 && (CONSOLE_LP_STRICT || written > 0));
		}
	} while (count > 0 && (CONSOLE_LP_STRICT || written > 0));

	parport_release (dev);
}

static struct console lpcons = {
	.name		= "lp",
	.write		= lp_console_write,
	.flags		= CON_PRINTBUFFER,
};

#endif /* console on line printer */

/* --- initialisation code ------------------------------------- */

static int parport_nr[LP_NO] = { [0 ... LP_NO-1] = LP_PARPORT_UNSPEC };
static char *parport[LP_NO];
static int reset;

module_param_array(parport, charp, NULL, 0);
module_param(reset, bool, 0);

#ifndef MODULE
static int __init lp_setup (char *str)
{
	static int parport_ptr;
	int x;

	if (get_option(&str, &x)) {
		if (x == 0) {
			/* disable driver on "lp=" or "lp=0" */
			parport_nr[0] = LP_PARPORT_OFF;
		} else {
			printk(KERN_WARNING "warning: 'lp=0x%x' is deprecated, ignored\n", x);
			return 0;
		}
	} else if (!strncmp(str, "parport", 7)) {
		int n = simple_strtoul(str+7, NULL, 10);
		if (parport_ptr < LP_NO)
			parport_nr[parport_ptr++] = n;
		else
			printk(KERN_INFO "lp: too many ports, %s ignored.\n",
			       str);
	} else if (!strcmp(str, "auto")) {
		parport_nr[0] = LP_PARPORT_AUTO;
	} else if (!strcmp(str, "none")) {
		parport_nr[parport_ptr++] = LP_PARPORT_NONE;
	} else if (!strcmp(str, "reset")) {
		reset = 1;
	}
	return 1;
}
#endif

static int lp_register(int nr, struct parport *port)
{
	lp_table[nr].dev = parport_register_device(port, "lp", 
						   lp_preempt, NULL, NULL, 0,
						   (void *) &lp_table[nr]);
	if (lp_table[nr].dev == NULL)
		return 1;
	lp_table[nr].flags |= LP_EXIST;

	if (reset)
		lp_reset(nr);

	device_create(lp_class, port->dev, MKDEV(LP_MAJOR, nr), NULL,
		      "lp%d", nr);

	printk(KERN_INFO "lp%d: using %s (%s).\n", nr, port->name, 
	       (port->irq == PARPORT_IRQ_NONE)?"polling":"interrupt-driven");

#ifdef CONFIG_LP_CONSOLE
	if (!nr) {
		if (port->modes & PARPORT_MODE_SAFEININT) {
			register_console(&lpcons);
			console_registered = port;
			printk (KERN_INFO "lp%d: console ready\n", CONSOLE_LP);
		} else
			printk (KERN_ERR "lp%d: cannot run console on %s\n",
				CONSOLE_LP, port->name);
	}
#endif

	return 0;
}

static void lp_attach (struct parport *port)
{
	unsigned int i;

	switch (parport_nr[0]) {
	case LP_PARPORT_UNSPEC:
	case LP_PARPORT_AUTO:
		if (parport_nr[0] == LP_PARPORT_AUTO &&
		    port->probe_info[0].class != PARPORT_CLASS_PRINTER)
			return;
		if (lp_count == LP_NO) {
			printk(KERN_INFO "lp: ignoring parallel port (max. %d)\n",LP_NO);
			return;
		}
		if (!lp_register(lp_count, port))
			lp_count++;
		break;

	default:
		for (i = 0; i < LP_NO; i++) {
			if (port->number == parport_nr[i]) {
				if (!lp_register(i, port))
					lp_count++;
				break;
			}
		}
		break;
	}
}

static void lp_detach (struct parport *port)
{
	/* Write this some day. */
#ifdef CONFIG_LP_CONSOLE
	if (console_registered == port) {
		unregister_console(&lpcons);
		console_registered = NULL;
	}
#endif /* CONFIG_LP_CONSOLE */
}

static struct parport_driver lp_driver = {
	.name = "lp",
	.attach = lp_attach,
	.detach = lp_detach,
};

static int __init lp_init (void)
{
	int i, err = 0;

	if (parport_nr[0] == LP_PARPORT_OFF)
		return 0;

	for (i = 0; i < LP_NO; i++) {
		lp_table[i].dev = NULL;
		lp_table[i].flags = 0;
		lp_table[i].chars = LP_INIT_CHAR;
		lp_table[i].time = LP_INIT_TIME;
		lp_table[i].wait = LP_INIT_WAIT;
		lp_table[i].lp_buffer = NULL;
#ifdef LP_STATS
		lp_table[i].lastcall = 0;
		lp_table[i].runchars = 0;
		memset (&lp_table[i].stats, 0, sizeof (struct lp_stats));
#endif
		lp_table[i].last_error = 0;
		init_waitqueue_head (&lp_table[i].waitq);
		init_waitqueue_head (&lp_table[i].dataq);
		mutex_init(&lp_table[i].port_mutex);
		lp_table[i].timeout = 10 * HZ;
	}

	if (register_chrdev (LP_MAJOR, "lp", &lp_fops)) {
		printk (KERN_ERR "lp: unable to get major %d\n", LP_MAJOR);
		return -EIO;
	}

	lp_class = class_create(THIS_MODULE, "printer");
	if (IS_ERR(lp_class)) {
		err = PTR_ERR(lp_class);
		goto out_reg;
	}

	if (parport_register_driver (&lp_driver)) {
		printk (KERN_ERR "lp: unable to register with parport\n");
		err = -EIO;
		goto out_class;
	}

	if (!lp_count) {
		printk (KERN_INFO "lp: driver loaded but no devices found\n");
#ifndef CONFIG_PARPORT_1284
		if (parport_nr[0] == LP_PARPORT_AUTO)
			printk (KERN_INFO "lp: (is IEEE 1284 support enabled?)\n");
#endif
	}

	return 0;

out_class:
	class_destroy(lp_class);
out_reg:
	unregister_chrdev(LP_MAJOR, "lp");
	return err;
}

static int __init lp_init_module (void)
{
	if (parport[0]) {
		/* The user gave some parameters.  Let's see what they were.  */
		if (!strncmp(parport[0], "auto", 4))
			parport_nr[0] = LP_PARPORT_AUTO;
		else {
			int n;
			for (n = 0; n < LP_NO && parport[n]; n++) {
				if (!strncmp(parport[n], "none", 4))
					parport_nr[n] = LP_PARPORT_NONE;
				else {
					char *ep;
					unsigned long r = simple_strtoul(parport[n], &ep, 0);
					if (ep != parport[n]) 
						parport_nr[n] = r;
					else {
						printk(KERN_ERR "lp: bad port specifier `%s'\n", parport[n]);
						return -ENODEV;
					}
				}
			}
		}
	}

	return lp_init();
}

static void lp_cleanup_module (void)
{
	unsigned int offset;

	parport_unregister_driver (&lp_driver);

#ifdef CONFIG_LP_CONSOLE
	unregister_console (&lpcons);
#endif

	unregister_chrdev(LP_MAJOR, "lp");
	for (offset = 0; offset < LP_NO; offset++) {
		if (lp_table[offset].dev == NULL)
			continue;
		parport_unregister_device(lp_table[offset].dev);
		device_destroy(lp_class, MKDEV(LP_MAJOR, offset));
	}
	class_destroy(lp_class);
}

__setup("lp=", lp_setup);
module_init(lp_init_module);
module_exit(lp_cleanup_module);

MODULE_ALIAS_CHARDEV_MAJOR(LP_MAJOR);
MODULE_LICENSE("GPL");