aboutsummaryrefslogtreecommitdiff
path: root/drivers/usb/misc/uss720.c
blob: 2734fe2b9c43b0443f7ef70b62d886ebe3c785bf (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
/*****************************************************************************/

/*
 *	uss720.c  --  USS720 USB Parport Cable.
 *
 *	Copyright (C) 1999, 2005
 *	    Thomas Sailer (t.sailer@alumni.ethz.ch)
 *
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation; either version 2 of the License, or
 *	(at your option) any later version.
 *
 *	This program is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *	GNU General Public License for more details.
 *
 *	You should have received a copy of the GNU General Public License
 *	along with this program; if not, write to the Free Software
 *	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *  Based on parport_pc.c
 *
 *  History:
 *   0.1  04.08.1999  Created
 *   0.2  07.08.1999  Some fixes mainly suggested by Tim Waugh
 *		      Interrupt handling currently disabled because
 *		      usb_request_irq crashes somewhere within ohci.c
 *		      for no apparent reason (that is for me, anyway)
 *		      ECP currently untested
 *   0.3  10.08.1999  fixing merge errors
 *   0.4  13.08.1999  Added Vendor/Product ID of Brad Hard's cable
 *   0.5  20.09.1999  usb_control_msg wrapper used
 *        Nov01.2000  usb_device_table support by Adam J. Richter
 *        08.04.2001  Identify version on module load.  gb
 *   0.6  02.09.2005  Fix "scheduling in interrupt" problem by making save/restore
 *                    context asynchronous
 *
 */

/*****************************************************************************/

#include <linux/module.h>
#include <linux/socket.h>
#include <linux/parport.h>
#include <linux/init.h>
#include <linux/usb.h>
#include <linux/delay.h>
#include <linux/completion.h>
#include <linux/kref.h>

/*
 * Version Information
 */
#define DRIVER_VERSION "v0.6"
#define DRIVER_AUTHOR "Thomas M. Sailer, t.sailer@alumni.ethz.ch"
#define DRIVER_DESC "USB Parport Cable driver for Cables using the Lucent Technologies USS720 Chip"

/* --------------------------------------------------------------------- */

struct parport_uss720_private {
	struct usb_device *usbdev;
	struct parport *pp;
	struct kref ref_count;
	__u8 reg[7];  /* USB registers */
	struct list_head asynclist;
	spinlock_t asynclock;
};

struct uss720_async_request {
	struct parport_uss720_private *priv;
	struct kref ref_count;
	struct list_head asynclist;
	struct completion compl;
	struct urb *urb;
	struct usb_ctrlrequest dr;
	__u8 reg[7];
};

/* --------------------------------------------------------------------- */

static void destroy_priv(struct kref *kref)
{
	struct parport_uss720_private *priv = container_of(kref, struct parport_uss720_private, ref_count);

	usb_put_dev(priv->usbdev);
	kfree(priv);
	dbg("destroying priv datastructure");
}

static void destroy_async(struct kref *kref)
{
	struct uss720_async_request *rq = container_of(kref, struct uss720_async_request, ref_count);
	struct parport_uss720_private *priv = rq->priv;
	unsigned long flags;

	if (likely(rq->urb))
		usb_free_urb(rq->urb);
	spin_lock_irqsave(&priv->asynclock, flags);
	list_del_init(&rq->asynclist);
	spin_unlock_irqrestore(&priv->asynclock, flags);
	kfree(rq);
	kref_put(&priv->ref_count, destroy_priv);
}

/* --------------------------------------------------------------------- */

static void async_complete(struct urb *urb)
{
	struct uss720_async_request *rq;
	struct parport *pp;
	struct parport_uss720_private *priv;
	int status = urb->status;

	rq = urb->context;
	priv = rq->priv;
	pp = priv->pp;
	if (status) {
		err("async_complete: urb error %d", status);
	} else if (rq->dr.bRequest == 3) {
		memcpy(priv->reg, rq->reg, sizeof(priv->reg));
#if 0
		dbg("async_complete regs %02x %02x %02x %02x %02x %02x %02x",
		    (unsigned int)priv->reg[0], (unsigned int)priv->reg[1], (unsigned int)priv->reg[2],
		    (unsigned int)priv->reg[3], (unsigned int)priv->reg[4], (unsigned int)priv->reg[5],
		    (unsigned int)priv->reg[6]);
#endif
		/* if nAck interrupts are enabled and we have an interrupt, call the interrupt procedure */
		if (rq->reg[2] & rq->reg[1] & 0x10 && pp)
			parport_generic_irq(0, pp);
	}
	complete(&rq->compl);
	kref_put(&rq->ref_count, destroy_async);
}

static struct uss720_async_request *submit_async_request(struct parport_uss720_private *priv,
							 __u8 request, __u8 requesttype, __u16 value, __u16 index,
							 gfp_t mem_flags)
{
	struct usb_device *usbdev;
	struct uss720_async_request *rq;
	unsigned long flags;
	int ret;

	if (!priv)
		return NULL;
	usbdev = priv->usbdev;
	if (!usbdev)
		return NULL;
	rq = kmalloc(sizeof(struct uss720_async_request), mem_flags);
	if (!rq) {
		err("submit_async_request out of memory");
		return NULL;
	}
	kref_init(&rq->ref_count);
	INIT_LIST_HEAD(&rq->asynclist);
	init_completion(&rq->compl);
	kref_get(&priv->ref_count);
	rq->priv = priv;
	rq->urb = usb_alloc_urb(0, mem_flags);
	if (!rq->urb) {
		kref_put(&rq->ref_count, destroy_async);
		err("submit_async_request out of memory");
		return NULL;
	}
	rq->dr.bRequestType = requesttype;
	rq->dr.bRequest = request;
	rq->dr.wValue = cpu_to_le16(value);
	rq->dr.wIndex = cpu_to_le16(index);
	rq->dr.wLength = cpu_to_le16((request == 3) ? sizeof(rq->reg) : 0);
	usb_fill_control_urb(rq->urb, usbdev, (requesttype & 0x80) ? usb_rcvctrlpipe(usbdev, 0) : usb_sndctrlpipe(usbdev, 0),
			     (unsigned char *)&rq->dr,
			     (request == 3) ? rq->reg : NULL, (request == 3) ? sizeof(rq->reg) : 0, async_complete, rq);
	/* rq->urb->transfer_flags |= URB_ASYNC_UNLINK; */
	spin_lock_irqsave(&priv->asynclock, flags);
	list_add_tail(&rq->asynclist, &priv->asynclist);
	spin_unlock_irqrestore(&priv->asynclock, flags);
	ret = usb_submit_urb(rq->urb, mem_flags);
	if (!ret) {
		kref_get(&rq->ref_count);
		return rq;
	}
	kref_put(&rq->ref_count, destroy_async);
	err("submit_async_request submit_urb failed with %d", ret);
	return NULL;
}

static unsigned int kill_all_async_requests_priv(struct parport_uss720_private *priv)
{
	struct uss720_async_request *rq;
	unsigned long flags;
	unsigned int ret = 0;

	spin_lock_irqsave(&priv->asynclock, flags);
	list_for_each_entry(rq, &priv->asynclist, asynclist) {
		usb_unlink_urb(rq->urb);
		ret++;
	}
	spin_unlock_irqrestore(&priv->asynclock, flags);
	return ret;
}

/* --------------------------------------------------------------------- */

static int get_1284_register(struct parport *pp, unsigned char reg, unsigned char *val, gfp_t mem_flags)
{
	struct parport_uss720_private *priv;
	struct uss720_async_request *rq;
	static const unsigned char regindex[9] = {
		4, 0, 1, 5, 5, 0, 2, 3, 6
	};
	int ret;

	if (!pp)
		return -EIO;
	priv = pp->private_data;
	rq = submit_async_request(priv, 3, 0xc0, ((unsigned int)reg) << 8, 0, mem_flags);
	if (!rq) {
		err("get_1284_register(%u) failed", (unsigned int)reg);
		return -EIO;
	}
	if (!val) {
		kref_put(&rq->ref_count, destroy_async);
		return 0;
	}
	if (wait_for_completion_timeout(&rq->compl, HZ)) {
		ret = rq->urb->status;
		*val = priv->reg[(reg >= 9) ? 0 : regindex[reg]];
		if (ret)
			warn("get_1284_register: usb error %d", ret);
		kref_put(&rq->ref_count, destroy_async);
		return ret;
	}
	warn("get_1284_register timeout");
	kill_all_async_requests_priv(priv);
	return -EIO;
}

static int set_1284_register(struct parport *pp, unsigned char reg, unsigned char val, gfp_t mem_flags)
{
	struct parport_uss720_private *priv;
	struct uss720_async_request *rq;

	if (!pp)
		return -EIO;
	priv = pp->private_data;
	rq = submit_async_request(priv, 4, 0x40, (((unsigned int)reg) << 8) | val, 0, mem_flags);
	if (!rq) {
		err("set_1284_register(%u,%u) failed", (unsigned int)reg, (unsigned int)val);
		return -EIO;
	}
	kref_put(&rq->ref_count, destroy_async);
	return 0;
}

/* --------------------------------------------------------------------- */

/* ECR modes */
#define ECR_SPP 00
#define ECR_PS2 01
#define ECR_PPF 02
#define ECR_ECP 03
#define ECR_EPP 04

/* Safely change the mode bits in the ECR */
static int change_mode(struct parport *pp, int m)
{
	struct parport_uss720_private *priv = pp->private_data;
	int mode;
	__u8 reg;

	if (get_1284_register(pp, 6, &reg, GFP_KERNEL))
		return -EIO;
	/* Bits <7:5> contain the mode. */
	mode = (priv->reg[2] >> 5) & 0x7;
	if (mode == m)
		return 0;
	/* We have to go through mode 000 or 001 */
	if (mode > ECR_PS2 && m > ECR_PS2)
		if (change_mode(pp, ECR_PS2))
			return -EIO;

	if (m <= ECR_PS2 && !(priv->reg[1] & 0x20)) {
		/* This mode resets the FIFO, so we may
		 * have to wait for it to drain first. */
		unsigned long expire = jiffies + pp->physport->cad->timeout;
		switch (mode) {
		case ECR_PPF: /* Parallel Port FIFO mode */
		case ECR_ECP: /* ECP Parallel Port mode */
			/* Poll slowly. */
			for (;;) {
				if (get_1284_register(pp, 6, &reg, GFP_KERNEL))
					return -EIO;
				if (priv->reg[2] & 0x01)
					break;
				if (time_after_eq (jiffies, expire))
					/* The FIFO is stuck. */
					return -EBUSY;
				msleep_interruptible(10);
				if (signal_pending (current))
					break;
			}
		}
	}
	/* Set the mode. */
	if (set_1284_register(pp, 6, m << 5, GFP_KERNEL))
		return -EIO;
	if (get_1284_register(pp, 6, &reg, GFP_KERNEL))
		return -EIO;
	return 0;
}

/*
 * Clear TIMEOUT BIT in EPP MODE
 */
static int clear_epp_timeout(struct parport *pp)
{
	unsigned char stat;

	if (get_1284_register(pp, 1, &stat, GFP_KERNEL))
		return 1;
	return stat & 1;
}

/*
 * Access functions.
 */
#if 0
static int uss720_irq(int usbstatus, void *buffer, int len, void *dev_id)
{
	struct parport *pp = (struct parport *)dev_id;
	struct parport_uss720_private *priv = pp->private_data;	

	if (usbstatus != 0 || len < 4 || !buffer)
		return 1;
	memcpy(priv->reg, buffer, 4);
	/* if nAck interrupts are enabled and we have an interrupt, call the interrupt procedure */
	if (priv->reg[2] & priv->reg[1] & 0x10)
		parport_generic_irq(0, pp);
	return 1;
}
#endif

static void parport_uss720_write_data(struct parport *pp, unsigned char d)
{
	set_1284_register(pp, 0, d, GFP_KERNEL);
}

static unsigned char parport_uss720_read_data(struct parport *pp)
{
	unsigned char ret;

	if (get_1284_register(pp, 0, &ret, GFP_KERNEL))
		return 0;
	return ret;
}

static void parport_uss720_write_control(struct parport *pp, unsigned char d)
{
	struct parport_uss720_private *priv = pp->private_data;	

	d = (d & 0xf) | (priv->reg[1] & 0xf0);
	if (set_1284_register(pp, 2, d, GFP_KERNEL))
		return;
	priv->reg[1] = d;
}

static unsigned char parport_uss720_read_control(struct parport *pp)
{
	struct parport_uss720_private *priv = pp->private_data;	
	return priv->reg[1] & 0xf; /* Use soft copy */
}

static unsigned char parport_uss720_frob_control(struct parport *pp, unsigned char mask, unsigned char val)
{
	struct parport_uss720_private *priv = pp->private_data;	
	unsigned char d;

	mask &= 0x0f;
	val &= 0x0f;
	d = (priv->reg[1] & (~mask)) ^ val;
	if (set_1284_register(pp, 2, d, GFP_KERNEL))
		return 0;
	priv->reg[1] = d;
	return d & 0xf;
}

static unsigned char parport_uss720_read_status(struct parport *pp)
{
	unsigned char ret;

	if (get_1284_register(pp, 1, &ret, GFP_KERNEL))
		return 0;
	return ret & 0xf8;
}

static void parport_uss720_disable_irq(struct parport *pp)
{
	struct parport_uss720_private *priv = pp->private_data;	
	unsigned char d;

	d = priv->reg[1] & ~0x10;
	if (set_1284_register(pp, 2, d, GFP_KERNEL))
		return;
	priv->reg[1] = d;
}

static void parport_uss720_enable_irq(struct parport *pp)
{
	struct parport_uss720_private *priv = pp->private_data;	
	unsigned char d;

	d = priv->reg[1] | 0x10;
	if (set_1284_register(pp, 2, d, GFP_KERNEL))
		return;
	priv->reg[1] = d;
}

static void parport_uss720_data_forward (struct parport *pp)
{
	struct parport_uss720_private *priv = pp->private_data;	
	unsigned char d;

	d = priv->reg[1] & ~0x20;
	if (set_1284_register(pp, 2, d, GFP_KERNEL))
		return;
	priv->reg[1] = d;
}

static void parport_uss720_data_reverse (struct parport *pp)
{
	struct parport_uss720_private *priv = pp->private_data;	
	unsigned char d;

	d = priv->reg[1] | 0x20;
	if (set_1284_register(pp, 2, d, GFP_KERNEL))
		return;
	priv->reg[1] = d;
}

static void parport_uss720_init_state(struct pardevice *dev, struct parport_state *s)
{
	s->u.pc.ctr = 0xc | (dev->irq_func ? 0x10 : 0x0);
	s->u.pc.ecr = 0x24;
}

static void parport_uss720_save_state(struct parport *pp, struct parport_state *s)
{
	struct parport_uss720_private *priv = pp->private_data;	

#if 0
	if (get_1284_register(pp, 2, NULL, GFP_ATOMIC))
		return;
#endif
	s->u.pc.ctr = priv->reg[1];
	s->u.pc.ecr = priv->reg[2];
}

static void parport_uss720_restore_state(struct parport *pp, struct parport_state *s)
{
	struct parport_uss720_private *priv = pp->private_data;

	set_1284_register(pp, 2, s->u.pc.ctr, GFP_ATOMIC);
	set_1284_register(pp, 6, s->u.pc.ecr, GFP_ATOMIC);
	get_1284_register(pp, 2, NULL, GFP_ATOMIC);
	priv->reg[1] = s->u.pc.ctr;
	priv->reg[2] = s->u.pc.ecr;
}

static size_t parport_uss720_epp_read_data(struct parport *pp, void *buf, size_t length, int flags)
{
	struct parport_uss720_private *priv = pp->private_data;	
	size_t got = 0;

	if (change_mode(pp, ECR_EPP))
		return 0;
	for (; got < length; got++) {
		if (get_1284_register(pp, 4, (char *)buf, GFP_KERNEL))
			break;
		buf++;
		if (priv->reg[0] & 0x01) {
			clear_epp_timeout(pp);
			break;
		}
	}
	change_mode(pp, ECR_PS2);
	return got;
}

static size_t parport_uss720_epp_write_data(struct parport *pp, const void *buf, size_t length, int flags)
{
#if 0
	struct parport_uss720_private *priv = pp->private_data;	
	size_t written = 0;

	if (change_mode(pp, ECR_EPP))
		return 0;
	for (; written < length; written++) {
		if (set_1284_register(pp, 4, (char *)buf, GFP_KERNEL))
			break;
		((char*)buf)++;
		if (get_1284_register(pp, 1, NULL, GFP_KERNEL))
			break;
		if (priv->reg[0] & 0x01) {
			clear_epp_timeout(pp);
			break;
		}
	}
	change_mode(pp, ECR_PS2);
	return written;
#else
	struct parport_uss720_private *priv = pp->private_data;
	struct usb_device *usbdev = priv->usbdev;
	int rlen;
	int i;

	if (!usbdev)
		return 0;
	if (change_mode(pp, ECR_EPP))
		return 0;
	i = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 1), (void *)buf, length, &rlen, 20000);
	if (i)
		printk(KERN_ERR "uss720: sendbulk ep 1 buf %p len %Zu rlen %u\n", buf, length, rlen);
	change_mode(pp, ECR_PS2);
	return rlen;
#endif
}

static size_t parport_uss720_epp_read_addr(struct parport *pp, void *buf, size_t length, int flags)
{
	struct parport_uss720_private *priv = pp->private_data;	
	size_t got = 0;

	if (change_mode(pp, ECR_EPP))
		return 0;
	for (; got < length; got++) {
		if (get_1284_register(pp, 3, (char *)buf, GFP_KERNEL))
			break;
		buf++;
		if (priv->reg[0] & 0x01) {
			clear_epp_timeout(pp);
			break;
		}
	}
	change_mode(pp, ECR_PS2);
	return got;
}

static size_t parport_uss720_epp_write_addr(struct parport *pp, const void *buf, size_t length, int flags)
{
	struct parport_uss720_private *priv = pp->private_data;	
	size_t written = 0;

	if (change_mode(pp, ECR_EPP))
		return 0;
	for (; written < length; written++) {
		if (set_1284_register(pp, 3, *(char *)buf, GFP_KERNEL))
			break;
		buf++;
		if (get_1284_register(pp, 1, NULL, GFP_KERNEL))
			break;
		if (priv->reg[0] & 0x01) {
			clear_epp_timeout(pp);
			break;
		}
	}
	change_mode(pp, ECR_PS2);
	return written;
}

static size_t parport_uss720_ecp_write_data(struct parport *pp, const void *buffer, size_t len, int flags)
{
	struct parport_uss720_private *priv = pp->private_data;
	struct usb_device *usbdev = priv->usbdev;
	int rlen;
	int i;

	if (!usbdev)
		return 0;
	if (change_mode(pp, ECR_ECP))
		return 0;
	i = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 1), (void *)buffer, len, &rlen, 20000);
	if (i)
		printk(KERN_ERR "uss720: sendbulk ep 1 buf %p len %Zu rlen %u\n", buffer, len, rlen);
	change_mode(pp, ECR_PS2);
	return rlen;
}

static size_t parport_uss720_ecp_read_data(struct parport *pp, void *buffer, size_t len, int flags)
{
	struct parport_uss720_private *priv = pp->private_data;
	struct usb_device *usbdev = priv->usbdev;
	int rlen;
	int i;

	if (!usbdev)
		return 0;
	if (change_mode(pp, ECR_ECP))
		return 0;
	i = usb_bulk_msg(usbdev, usb_rcvbulkpipe(usbdev, 2), buffer, len, &rlen, 20000);
	if (i)
		printk(KERN_ERR "uss720: recvbulk ep 2 buf %p len %Zu rlen %u\n", buffer, len, rlen);
	change_mode(pp, ECR_PS2);
	return rlen;
}

static size_t parport_uss720_ecp_write_addr(struct parport *pp, const void *buffer, size_t len, int flags)
{
	size_t written = 0;

	if (change_mode(pp, ECR_ECP))
		return 0;
	for (; written < len; written++) {
		if (set_1284_register(pp, 5, *(char *)buffer, GFP_KERNEL))
			break;
		buffer++;
	}
	change_mode(pp, ECR_PS2);
	return written;
}

static size_t parport_uss720_write_compat(struct parport *pp, const void *buffer, size_t len, int flags)
{
	struct parport_uss720_private *priv = pp->private_data;
	struct usb_device *usbdev = priv->usbdev;
	int rlen;
	int i;

	if (!usbdev)
		return 0;
	if (change_mode(pp, ECR_PPF))
		return 0;
	i = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 1), (void *)buffer, len, &rlen, 20000);
	if (i)
		printk(KERN_ERR "uss720: sendbulk ep 1 buf %p len %Zu rlen %u\n", buffer, len, rlen);
	change_mode(pp, ECR_PS2);
	return rlen;
}

/* --------------------------------------------------------------------- */

static struct parport_operations parport_uss720_ops = 
{
	.owner =		THIS_MODULE,
	.write_data =		parport_uss720_write_data,
	.read_data =		parport_uss720_read_data,

	.write_control =	parport_uss720_write_control,
	.read_control =		parport_uss720_read_control,
	.frob_control =		parport_uss720_frob_control,

	.read_status =		parport_uss720_read_status,

	.enable_irq =		parport_uss720_enable_irq,
	.disable_irq =		parport_uss720_disable_irq,

	.data_forward =		parport_uss720_data_forward,
	.data_reverse =		parport_uss720_data_reverse,

	.init_state =		parport_uss720_init_state,
	.save_state =		parport_uss720_save_state,
	.restore_state =	parport_uss720_restore_state,

	.epp_write_data =	parport_uss720_epp_write_data,
	.epp_read_data =	parport_uss720_epp_read_data,
	.epp_write_addr =	parport_uss720_epp_write_addr,
	.epp_read_addr =	parport_uss720_epp_read_addr,

	.ecp_write_data =	parport_uss720_ecp_write_data,
	.ecp_read_data =	parport_uss720_ecp_read_data,
	.ecp_write_addr =	parport_uss720_ecp_write_addr,

	.compat_write_data =	parport_uss720_write_compat,
	.nibble_read_data =	parport_ieee1284_read_nibble,
	.byte_read_data =	parport_ieee1284_read_byte,
};

/* --------------------------------------------------------------------- */

static int uss720_probe(struct usb_interface *intf,
			const struct usb_device_id *id)
{
	struct usb_device *usbdev = usb_get_dev(interface_to_usbdev(intf));
	struct usb_host_interface *interface;
	struct usb_host_endpoint *endpoint;
	struct parport_uss720_private *priv;
	struct parport *pp;
	unsigned char reg;
	int i;

	dbg("probe: vendor id 0x%x, device id 0x%x\n",
	    le16_to_cpu(usbdev->descriptor.idVendor),
	    le16_to_cpu(usbdev->descriptor.idProduct));

	/* our known interfaces have 3 alternate settings */
	if (intf->num_altsetting != 3) {
		usb_put_dev(usbdev);
		return -ENODEV;
	}
	i = usb_set_interface(usbdev, intf->altsetting->desc.bInterfaceNumber, 2);
	dbg("set inteface result %d", i);

	interface = intf->cur_altsetting;

	/*
	 * Allocate parport interface 
	 */
	if (!(priv = kzalloc(sizeof(struct parport_uss720_private), GFP_KERNEL))) {
		usb_put_dev(usbdev);
		return -ENOMEM;
	}
	priv->pp = NULL;
	priv->usbdev = usbdev;
	kref_init(&priv->ref_count);
	spin_lock_init(&priv->asynclock);
	INIT_LIST_HEAD(&priv->asynclist);
	if (!(pp = parport_register_port(0, PARPORT_IRQ_NONE, PARPORT_DMA_NONE, &parport_uss720_ops))) {
		warn("could not register parport");
		goto probe_abort;
	}

	priv->pp = pp;
	pp->private_data = priv;
	pp->modes = PARPORT_MODE_PCSPP | PARPORT_MODE_TRISTATE | PARPORT_MODE_EPP | PARPORT_MODE_ECP | PARPORT_MODE_COMPAT;

	/* set the USS720 control register to manual mode, no ECP compression, enable all ints */
	set_1284_register(pp, 7, 0x00, GFP_KERNEL);
	set_1284_register(pp, 6, 0x30, GFP_KERNEL);  /* PS/2 mode */
	set_1284_register(pp, 2, 0x0c, GFP_KERNEL);
	/* debugging */
	get_1284_register(pp, 0, &reg, GFP_KERNEL);
	dbg("reg: %02x %02x %02x %02x %02x %02x %02x",
	    priv->reg[0], priv->reg[1], priv->reg[2], priv->reg[3], priv->reg[4], priv->reg[5], priv->reg[6]);

	endpoint = &interface->endpoint[2];
	dbg("epaddr %d interval %d", endpoint->desc.bEndpointAddress, endpoint->desc.bInterval);
	parport_announce_port(pp);

	usb_set_intfdata(intf, pp);
	return 0;

probe_abort:
	kill_all_async_requests_priv(priv);
	kref_put(&priv->ref_count, destroy_priv);
	return -ENODEV;
}

static void uss720_disconnect(struct usb_interface *intf)
{
	struct parport *pp = usb_get_intfdata(intf);
	struct parport_uss720_private *priv;
	struct usb_device *usbdev;

	dbg("disconnect");
	usb_set_intfdata(intf, NULL);
	if (pp) {
		priv = pp->private_data;
		usbdev = priv->usbdev;
		priv->usbdev = NULL;
		priv->pp = NULL;
		dbg("parport_remove_port");
		parport_remove_port(pp);
		parport_put_port(pp);
		kill_all_async_requests_priv(priv);
		kref_put(&priv->ref_count, destroy_priv);
	}
	dbg("disconnect done");
}

/* table of cables that work through this driver */
static struct usb_device_id uss720_table [] = {
	{ USB_DEVICE(0x047e, 0x1001) },
	{ USB_DEVICE(0x0557, 0x2001) },
	{ USB_DEVICE(0x0729, 0x1284) },
	{ USB_DEVICE(0x1293, 0x0002) },
	{ }						/* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, uss720_table);


static struct usb_driver uss720_driver = {
	.name =		"uss720",
	.probe =	uss720_probe,
	.disconnect =	uss720_disconnect,
	.id_table =	uss720_table,
};

/* --------------------------------------------------------------------- */

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

static int __init uss720_init(void)
{
	int retval;
	retval = usb_register(&uss720_driver);
	if (retval)
		goto out;

	info(DRIVER_VERSION ":" DRIVER_DESC);
	info("NOTE: this is a special purpose driver to allow nonstandard");
	info("protocols (eg. bitbang) over USS720 usb to parallel cables");
	info("If you just want to connect to a printer, use usblp instead");
out:
	return retval;
}

static void __exit uss720_cleanup(void)
{
	usb_deregister(&uss720_driver);
}

module_init(uss720_init);
module_exit(uss720_cleanup);

/* --------------------------------------------------------------------- */