xref: /linux/drivers/usb/misc/uss720.c (revision 1b78070aaef63512688aebfbc82365ef9d6660f1)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*****************************************************************************/
3 
4 /*
5  *	uss720.c  --  USS720 USB Parport Cable.
6  *
7  *	Copyright (C) 1999, 2005, 2010
8  *	    Thomas Sailer (t.sailer@alumni.ethz.ch)
9  *
10  *  Based on parport_pc.c
11  *
12  *  History:
13  *   0.1  04.08.1999  Created
14  *   0.2  07.08.1999  Some fixes mainly suggested by Tim Waugh
15  *		      Interrupt handling currently disabled because
16  *		      usb_request_irq crashes somewhere within ohci.c
17  *		      for no apparent reason (that is for me, anyway)
18  *		      ECP currently untested
19  *   0.3  10.08.1999  fixing merge errors
20  *   0.4  13.08.1999  Added Vendor/Product ID of Brad Hard's cable
21  *   0.5  20.09.1999  usb_control_msg wrapper used
22  *        Nov01.2000  usb_device_table support by Adam J. Richter
23  *        08.04.2001  Identify version on module load.  gb
24  *   0.6  02.09.2005  Fix "scheduling in interrupt" problem by making save/restore
25  *                    context asynchronous
26  *
27  */
28 
29 /*****************************************************************************/
30 
31 #include <linux/module.h>
32 #include <linux/socket.h>
33 #include <linux/parport.h>
34 #include <linux/init.h>
35 #include <linux/usb.h>
36 #include <linux/delay.h>
37 #include <linux/completion.h>
38 #include <linux/kref.h>
39 #include <linux/slab.h>
40 #include <linux/sched/signal.h>
41 
42 #define DRIVER_AUTHOR "Thomas M. Sailer, t.sailer@alumni.ethz.ch"
43 #define DRIVER_DESC "USB Parport Cable driver for Cables using the Lucent Technologies USS720 Chip"
44 
45 /* --------------------------------------------------------------------- */
46 
47 struct parport_uss720_private {
48 	struct usb_device *usbdev;
49 	struct parport *pp;
50 	struct kref ref_count;
51 	__u8 reg[7];  /* USB registers */
52 	struct list_head asynclist;
53 	spinlock_t asynclock;
54 };
55 
56 struct uss720_async_request {
57 	struct parport_uss720_private *priv;
58 	struct kref ref_count;
59 	struct list_head asynclist;
60 	struct completion compl;
61 	struct urb *urb;
62 	struct usb_ctrlrequest *dr;
63 	__u8 reg[7];
64 };
65 
66 /* --------------------------------------------------------------------- */
67 
68 static void destroy_priv(struct kref *kref)
69 {
70 	struct parport_uss720_private *priv = container_of(kref, struct parport_uss720_private, ref_count);
71 
72 	dev_dbg(&priv->usbdev->dev, "destroying priv datastructure\n");
73 	usb_put_dev(priv->usbdev);
74 	priv->usbdev = NULL;
75 	kfree(priv);
76 }
77 
78 static void destroy_async(struct kref *kref)
79 {
80 	struct uss720_async_request *rq = container_of(kref, struct uss720_async_request, ref_count);
81 	struct parport_uss720_private *priv = rq->priv;
82 	unsigned long flags;
83 
84 	if (likely(rq->urb))
85 		usb_free_urb(rq->urb);
86 	kfree(rq->dr);
87 	spin_lock_irqsave(&priv->asynclock, flags);
88 	list_del_init(&rq->asynclist);
89 	spin_unlock_irqrestore(&priv->asynclock, flags);
90 	kfree(rq);
91 	kref_put(&priv->ref_count, destroy_priv);
92 }
93 
94 /* --------------------------------------------------------------------- */
95 
96 static void async_complete(struct urb *urb)
97 {
98 	struct uss720_async_request *rq;
99 	struct parport *pp;
100 	struct parport_uss720_private *priv;
101 	int status = urb->status;
102 
103 	rq = urb->context;
104 	priv = rq->priv;
105 	pp = priv->pp;
106 	if (status) {
107 		dev_err(&urb->dev->dev, "async_complete: urb error %d\n",
108 			status);
109 	} else if (rq->dr->bRequest == 3) {
110 		memcpy(priv->reg, rq->reg, sizeof(priv->reg));
111 #if 0
112 		dev_dbg(&priv->usbdev->dev, "async_complete regs %7ph\n",
113 			priv->reg);
114 #endif
115 		/* if nAck interrupts are enabled and we have an interrupt, call the interrupt procedure */
116 		if (rq->reg[2] & rq->reg[1] & 0x10 && pp)
117 			parport_generic_irq(pp);
118 	}
119 	complete(&rq->compl);
120 	kref_put(&rq->ref_count, destroy_async);
121 }
122 
123 static struct uss720_async_request *submit_async_request(struct parport_uss720_private *priv,
124 							 __u8 request, __u8 requesttype, __u16 value, __u16 index,
125 							 gfp_t mem_flags)
126 {
127 	struct usb_device *usbdev;
128 	struct uss720_async_request *rq;
129 	unsigned long flags;
130 	int ret;
131 
132 	if (!priv)
133 		return NULL;
134 	usbdev = priv->usbdev;
135 	if (!usbdev)
136 		return NULL;
137 	rq = kzalloc_obj(struct uss720_async_request, mem_flags);
138 	if (!rq)
139 		return NULL;
140 	kref_init(&rq->ref_count);
141 	INIT_LIST_HEAD(&rq->asynclist);
142 	init_completion(&rq->compl);
143 	kref_get(&priv->ref_count);
144 	rq->priv = priv;
145 	rq->urb = usb_alloc_urb(0, mem_flags);
146 	if (!rq->urb) {
147 		kref_put(&rq->ref_count, destroy_async);
148 		return NULL;
149 	}
150 	rq->dr = kmalloc_obj(*rq->dr, mem_flags);
151 	if (!rq->dr) {
152 		kref_put(&rq->ref_count, destroy_async);
153 		return NULL;
154 	}
155 	rq->dr->bRequestType = requesttype;
156 	rq->dr->bRequest = request;
157 	rq->dr->wValue = cpu_to_le16(value);
158 	rq->dr->wIndex = cpu_to_le16(index);
159 	rq->dr->wLength = cpu_to_le16((request == 3) ? sizeof(rq->reg) : 0);
160 	usb_fill_control_urb(rq->urb, usbdev, (requesttype & 0x80) ? usb_rcvctrlpipe(usbdev, 0) : usb_sndctrlpipe(usbdev, 0),
161 			     (unsigned char *)rq->dr,
162 			     (request == 3) ? rq->reg : NULL, (request == 3) ? sizeof(rq->reg) : 0, async_complete, rq);
163 	/* rq->urb->transfer_flags |= URB_ASYNC_UNLINK; */
164 	spin_lock_irqsave(&priv->asynclock, flags);
165 	list_add_tail(&rq->asynclist, &priv->asynclist);
166 	spin_unlock_irqrestore(&priv->asynclock, flags);
167 	kref_get(&rq->ref_count);
168 	ret = usb_submit_urb(rq->urb, mem_flags);
169 	if (!ret)
170 		return rq;
171 	destroy_async(&rq->ref_count);
172 	dev_err(&usbdev->dev, "submit_async_request submit_urb failed with %d\n", ret);
173 	return NULL;
174 }
175 
176 static unsigned int kill_all_async_requests_priv(struct parport_uss720_private *priv)
177 {
178 	struct uss720_async_request *rq;
179 	unsigned long flags;
180 	unsigned int ret = 0;
181 
182 	spin_lock_irqsave(&priv->asynclock, flags);
183 	list_for_each_entry(rq, &priv->asynclist, asynclist) {
184 		usb_unlink_urb(rq->urb);
185 		ret++;
186 	}
187 	spin_unlock_irqrestore(&priv->asynclock, flags);
188 	return ret;
189 }
190 
191 /* --------------------------------------------------------------------- */
192 
193 static int get_1284_register(struct parport *pp, unsigned char reg, unsigned char *val, gfp_t mem_flags)
194 {
195 	struct parport_uss720_private *priv;
196 	struct uss720_async_request *rq;
197 	static const unsigned char regindex[9] = {
198 		4, 0, 1, 5, 5, 0, 2, 3, 6
199 	};
200 	int ret;
201 
202 	if (!pp)
203 		return -EIO;
204 	priv = pp->private_data;
205 	rq = submit_async_request(priv, 3, 0xc0, ((unsigned int)reg) << 8, 0, mem_flags);
206 	if (!rq) {
207 		dev_err(&priv->usbdev->dev, "get_1284_register(%u) failed",
208 			(unsigned int)reg);
209 		return -EIO;
210 	}
211 	if (!val) {
212 		kref_put(&rq->ref_count, destroy_async);
213 		return 0;
214 	}
215 	if (wait_for_completion_timeout(&rq->compl, HZ)) {
216 		ret = rq->urb->status;
217 		*val = priv->reg[(reg >= 9) ? 0 : regindex[reg]];
218 		if (ret)
219 			printk(KERN_WARNING "get_1284_register: "
220 			       "usb error %d\n", ret);
221 		kref_put(&rq->ref_count, destroy_async);
222 		return ret;
223 	}
224 	printk(KERN_WARNING "get_1284_register timeout\n");
225 	kill_all_async_requests_priv(priv);
226 	kref_put(&rq->ref_count, destroy_async);
227 	return -EIO;
228 }
229 
230 static int set_1284_register(struct parport *pp, unsigned char reg, unsigned char val, gfp_t mem_flags)
231 {
232 	struct parport_uss720_private *priv;
233 	struct uss720_async_request *rq;
234 
235 	if (!pp)
236 		return -EIO;
237 	priv = pp->private_data;
238 	rq = submit_async_request(priv, 4, 0x40, (((unsigned int)reg) << 8) | val, 0, mem_flags);
239 	if (!rq) {
240 		dev_err(&priv->usbdev->dev, "set_1284_register(%u,%u) failed",
241 			(unsigned int)reg, (unsigned int)val);
242 		return -EIO;
243 	}
244 	kref_put(&rq->ref_count, destroy_async);
245 	return 0;
246 }
247 
248 /* --------------------------------------------------------------------- */
249 
250 /* ECR modes */
251 #define ECR_SPP 00
252 #define ECR_PS2 01
253 #define ECR_PPF 02
254 #define ECR_ECP 03
255 #define ECR_EPP 04
256 
257 /* Safely change the mode bits in the ECR */
258 static int change_mode(struct parport *pp, int m)
259 {
260 	struct parport_uss720_private *priv = pp->private_data;
261 	int mode;
262 	__u8 reg;
263 
264 	if (get_1284_register(pp, 6, &reg, GFP_KERNEL))
265 		return -EIO;
266 	/* Bits <7:5> contain the mode. */
267 	mode = (priv->reg[2] >> 5) & 0x7;
268 	if (mode == m)
269 		return 0;
270 	/* We have to go through mode 000 or 001 */
271 	if (mode > ECR_PS2 && m > ECR_PS2)
272 		if (change_mode(pp, ECR_PS2))
273 			return -EIO;
274 
275 	if (m <= ECR_PS2 && !(priv->reg[1] & 0x20)) {
276 		/* This mode resets the FIFO, so we may
277 		 * have to wait for it to drain first. */
278 		unsigned long expire = jiffies + pp->physport->cad->timeout;
279 		switch (mode) {
280 		case ECR_PPF: /* Parallel Port FIFO mode */
281 		case ECR_ECP: /* ECP Parallel Port mode */
282 			/* Poll slowly. */
283 			for (;;) {
284 				if (get_1284_register(pp, 6, &reg, GFP_KERNEL))
285 					return -EIO;
286 				if (priv->reg[2] & 0x01)
287 					break;
288 				if (time_after_eq (jiffies, expire))
289 					/* The FIFO is stuck. */
290 					return -EBUSY;
291 				msleep_interruptible(10);
292 				if (signal_pending (current))
293 					break;
294 			}
295 		}
296 	}
297 	/* Set the mode. */
298 	if (set_1284_register(pp, 6, m << 5, GFP_KERNEL))
299 		return -EIO;
300 	if (get_1284_register(pp, 6, &reg, GFP_KERNEL))
301 		return -EIO;
302 	return 0;
303 }
304 
305 /*
306  * Clear TIMEOUT BIT in EPP MODE
307  */
308 static int clear_epp_timeout(struct parport *pp)
309 {
310 	unsigned char stat;
311 
312 	if (get_1284_register(pp, 1, &stat, GFP_KERNEL))
313 		return 1;
314 	return stat & 1;
315 }
316 
317 /*
318  * Access functions.
319  */
320 #if 0
321 static int uss720_irq(int usbstatus, void *buffer, int len, void *dev_id)
322 {
323 	struct parport *pp = (struct parport *)dev_id;
324 	struct parport_uss720_private *priv = pp->private_data;
325 
326 	if (usbstatus != 0 || len < 4 || !buffer)
327 		return 1;
328 	memcpy(priv->reg, buffer, 4);
329 	/* if nAck interrupts are enabled and we have an interrupt, call the interrupt procedure */
330 	if (priv->reg[2] & priv->reg[1] & 0x10)
331 		parport_generic_irq(pp);
332 	return 1;
333 }
334 #endif
335 
336 static void parport_uss720_write_data(struct parport *pp, unsigned char d)
337 {
338 	set_1284_register(pp, 0, d, GFP_KERNEL);
339 }
340 
341 static unsigned char parport_uss720_read_data(struct parport *pp)
342 {
343 	unsigned char ret;
344 
345 	if (get_1284_register(pp, 0, &ret, GFP_KERNEL))
346 		return 0;
347 	return ret;
348 }
349 
350 static void parport_uss720_write_control(struct parport *pp, unsigned char d)
351 {
352 	struct parport_uss720_private *priv = pp->private_data;
353 
354 	d = (d & 0xf) | (priv->reg[1] & 0xf0);
355 	if (set_1284_register(pp, 2, d, GFP_KERNEL))
356 		return;
357 	priv->reg[1] = d;
358 }
359 
360 static unsigned char parport_uss720_read_control(struct parport *pp)
361 {
362 	struct parport_uss720_private *priv = pp->private_data;
363 	return priv->reg[1] & 0xf; /* Use soft copy */
364 }
365 
366 static unsigned char parport_uss720_frob_control(struct parport *pp, unsigned char mask, unsigned char val)
367 {
368 	struct parport_uss720_private *priv = pp->private_data;
369 	unsigned char d;
370 
371 	mask &= 0x0f;
372 	val &= 0x0f;
373 	d = (priv->reg[1] & (~mask)) ^ val;
374 	if (set_1284_register(pp, 2, d, GFP_ATOMIC))
375 		return 0;
376 	priv->reg[1] = d;
377 	return d & 0xf;
378 }
379 
380 static unsigned char parport_uss720_read_status(struct parport *pp)
381 {
382 	unsigned char ret;
383 
384 	if (get_1284_register(pp, 1, &ret, GFP_ATOMIC))
385 		return 0;
386 	return ret & 0xf8;
387 }
388 
389 static void parport_uss720_disable_irq(struct parport *pp)
390 {
391 	struct parport_uss720_private *priv = pp->private_data;
392 	unsigned char d;
393 
394 	d = priv->reg[1] & ~0x10;
395 	if (set_1284_register(pp, 2, d, GFP_KERNEL))
396 		return;
397 	priv->reg[1] = d;
398 }
399 
400 static void parport_uss720_enable_irq(struct parport *pp)
401 {
402 	struct parport_uss720_private *priv = pp->private_data;
403 	unsigned char d;
404 
405 	d = priv->reg[1] | 0x10;
406 	if (set_1284_register(pp, 2, d, GFP_KERNEL))
407 		return;
408 	priv->reg[1] = d;
409 }
410 
411 static void parport_uss720_data_forward (struct parport *pp)
412 {
413 	struct parport_uss720_private *priv = pp->private_data;
414 	unsigned char d;
415 
416 	d = priv->reg[1] & ~0x20;
417 	if (set_1284_register(pp, 2, d, GFP_KERNEL))
418 		return;
419 	priv->reg[1] = d;
420 }
421 
422 static void parport_uss720_data_reverse (struct parport *pp)
423 {
424 	struct parport_uss720_private *priv = pp->private_data;
425 	unsigned char d;
426 
427 	d = priv->reg[1] | 0x20;
428 	if (set_1284_register(pp, 2, d, GFP_KERNEL))
429 		return;
430 	priv->reg[1] = d;
431 }
432 
433 static void parport_uss720_init_state(struct pardevice *dev, struct parport_state *s)
434 {
435 	s->u.pc.ctr = 0xc | (dev->irq_func ? 0x10 : 0x0);
436 	s->u.pc.ecr = 0x24;
437 }
438 
439 static void parport_uss720_save_state(struct parport *pp, struct parport_state *s)
440 {
441 	struct parport_uss720_private *priv = pp->private_data;
442 
443 #if 0
444 	if (get_1284_register(pp, 2, NULL, GFP_ATOMIC))
445 		return;
446 #endif
447 	s->u.pc.ctr = priv->reg[1];
448 	s->u.pc.ecr = priv->reg[2];
449 }
450 
451 static void parport_uss720_restore_state(struct parport *pp, struct parport_state *s)
452 {
453 	struct parport_uss720_private *priv = pp->private_data;
454 
455 	set_1284_register(pp, 2, s->u.pc.ctr, GFP_ATOMIC);
456 	set_1284_register(pp, 6, s->u.pc.ecr, GFP_ATOMIC);
457 	get_1284_register(pp, 2, NULL, GFP_ATOMIC);
458 	priv->reg[1] = s->u.pc.ctr;
459 	priv->reg[2] = s->u.pc.ecr;
460 }
461 
462 static size_t parport_uss720_epp_read_data(struct parport *pp, void *buf, size_t length, int flags)
463 {
464 	struct parport_uss720_private *priv = pp->private_data;
465 	size_t got = 0;
466 
467 	if (change_mode(pp, ECR_EPP))
468 		return 0;
469 	for (; got < length; got++) {
470 		if (get_1284_register(pp, 4, (char *)buf, GFP_KERNEL))
471 			break;
472 		buf++;
473 		if (priv->reg[0] & 0x01) {
474 			clear_epp_timeout(pp);
475 			break;
476 		}
477 	}
478 	change_mode(pp, ECR_PS2);
479 	return got;
480 }
481 
482 static size_t parport_uss720_epp_write_data(struct parport *pp, const void *buf, size_t length, int flags)
483 {
484 #if 0
485 	struct parport_uss720_private *priv = pp->private_data;
486 	size_t written = 0;
487 
488 	if (change_mode(pp, ECR_EPP))
489 		return 0;
490 	for (; written < length; written++) {
491 		if (set_1284_register(pp, 4, (char *)buf, GFP_KERNEL))
492 			break;
493 		((char*)buf)++;
494 		if (get_1284_register(pp, 1, NULL, GFP_KERNEL))
495 			break;
496 		if (priv->reg[0] & 0x01) {
497 			clear_epp_timeout(pp);
498 			break;
499 		}
500 	}
501 	change_mode(pp, ECR_PS2);
502 	return written;
503 #else
504 	struct parport_uss720_private *priv = pp->private_data;
505 	struct usb_device *usbdev = priv->usbdev;
506 	int rlen = 0;
507 	int i;
508 
509 	if (!usbdev)
510 		return 0;
511 	if (change_mode(pp, ECR_EPP))
512 		return 0;
513 	i = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 1), (void *)buf, length, &rlen, 20000);
514 	if (i)
515 		printk(KERN_ERR "uss720: sendbulk ep 1 buf %p len %zu rlen %u\n", buf, length, rlen);
516 	change_mode(pp, ECR_PS2);
517 	return rlen;
518 #endif
519 }
520 
521 static size_t parport_uss720_epp_read_addr(struct parport *pp, void *buf, size_t length, int flags)
522 {
523 	struct parport_uss720_private *priv = pp->private_data;
524 	size_t got = 0;
525 
526 	if (change_mode(pp, ECR_EPP))
527 		return 0;
528 	for (; got < length; got++) {
529 		if (get_1284_register(pp, 3, (char *)buf, GFP_KERNEL))
530 			break;
531 		buf++;
532 		if (priv->reg[0] & 0x01) {
533 			clear_epp_timeout(pp);
534 			break;
535 		}
536 	}
537 	change_mode(pp, ECR_PS2);
538 	return got;
539 }
540 
541 static size_t parport_uss720_epp_write_addr(struct parport *pp, const void *buf, size_t length, int flags)
542 {
543 	struct parport_uss720_private *priv = pp->private_data;
544 	size_t written = 0;
545 
546 	if (change_mode(pp, ECR_EPP))
547 		return 0;
548 	for (; written < length; written++) {
549 		if (set_1284_register(pp, 3, *(char *)buf, GFP_KERNEL))
550 			break;
551 		buf++;
552 		if (get_1284_register(pp, 1, NULL, GFP_KERNEL))
553 			break;
554 		if (priv->reg[0] & 0x01) {
555 			clear_epp_timeout(pp);
556 			break;
557 		}
558 	}
559 	change_mode(pp, ECR_PS2);
560 	return written;
561 }
562 
563 static size_t parport_uss720_ecp_write_data(struct parport *pp, const void *buffer, size_t len, int flags)
564 {
565 	struct parport_uss720_private *priv = pp->private_data;
566 	struct usb_device *usbdev = priv->usbdev;
567 	int rlen = 0;
568 	int i;
569 
570 	if (!usbdev)
571 		return 0;
572 	if (change_mode(pp, ECR_ECP))
573 		return 0;
574 	i = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 1), (void *)buffer, len, &rlen, 20000);
575 	if (i)
576 		printk(KERN_ERR "uss720: sendbulk ep 1 buf %p len %zu rlen %u\n", buffer, len, rlen);
577 	change_mode(pp, ECR_PS2);
578 	return rlen;
579 }
580 
581 static size_t parport_uss720_ecp_read_data(struct parport *pp, void *buffer, size_t len, int flags)
582 {
583 	struct parport_uss720_private *priv = pp->private_data;
584 	struct usb_device *usbdev = priv->usbdev;
585 	int rlen = 0;
586 	int i;
587 
588 	if (!usbdev)
589 		return 0;
590 	if (change_mode(pp, ECR_ECP))
591 		return 0;
592 	i = usb_bulk_msg(usbdev, usb_rcvbulkpipe(usbdev, 2), buffer, len, &rlen, 20000);
593 	if (i)
594 		printk(KERN_ERR "uss720: recvbulk ep 2 buf %p len %zu rlen %u\n", buffer, len, rlen);
595 	change_mode(pp, ECR_PS2);
596 	return rlen;
597 }
598 
599 static size_t parport_uss720_ecp_write_addr(struct parport *pp, const void *buffer, size_t len, int flags)
600 {
601 	size_t written = 0;
602 
603 	if (change_mode(pp, ECR_ECP))
604 		return 0;
605 	for (; written < len; written++) {
606 		if (set_1284_register(pp, 5, *(char *)buffer, GFP_KERNEL))
607 			break;
608 		buffer++;
609 	}
610 	change_mode(pp, ECR_PS2);
611 	return written;
612 }
613 
614 static size_t parport_uss720_write_compat(struct parport *pp, const void *buffer, size_t len, int flags)
615 {
616 	struct parport_uss720_private *priv = pp->private_data;
617 	struct usb_device *usbdev = priv->usbdev;
618 	int rlen = 0;
619 	int i;
620 
621 	if (!usbdev)
622 		return 0;
623 	if (change_mode(pp, ECR_PPF))
624 		return 0;
625 	i = usb_bulk_msg(usbdev, usb_sndbulkpipe(usbdev, 1), (void *)buffer, len, &rlen, 20000);
626 	if (i)
627 		printk(KERN_ERR "uss720: sendbulk ep 1 buf %p len %zu rlen %u\n", buffer, len, rlen);
628 	change_mode(pp, ECR_PS2);
629 	return rlen;
630 }
631 
632 /* --------------------------------------------------------------------- */
633 
634 static struct parport_operations parport_uss720_ops =
635 {
636 	.owner =		THIS_MODULE,
637 	.write_data =		parport_uss720_write_data,
638 	.read_data =		parport_uss720_read_data,
639 
640 	.write_control =	parport_uss720_write_control,
641 	.read_control =		parport_uss720_read_control,
642 	.frob_control =		parport_uss720_frob_control,
643 
644 	.read_status =		parport_uss720_read_status,
645 
646 	.enable_irq =		parport_uss720_enable_irq,
647 	.disable_irq =		parport_uss720_disable_irq,
648 
649 	.data_forward =		parport_uss720_data_forward,
650 	.data_reverse =		parport_uss720_data_reverse,
651 
652 	.init_state =		parport_uss720_init_state,
653 	.save_state =		parport_uss720_save_state,
654 	.restore_state =	parport_uss720_restore_state,
655 
656 	.epp_write_data =	parport_uss720_epp_write_data,
657 	.epp_read_data =	parport_uss720_epp_read_data,
658 	.epp_write_addr =	parport_uss720_epp_write_addr,
659 	.epp_read_addr =	parport_uss720_epp_read_addr,
660 
661 	.ecp_write_data =	parport_uss720_ecp_write_data,
662 	.ecp_read_data =	parport_uss720_ecp_read_data,
663 	.ecp_write_addr =	parport_uss720_ecp_write_addr,
664 
665 	.compat_write_data =	parport_uss720_write_compat,
666 	.nibble_read_data =	parport_ieee1284_read_nibble,
667 	.byte_read_data =	parport_ieee1284_read_byte,
668 };
669 
670 /* --------------------------------------------------------------------- */
671 
672 static int uss720_probe(struct usb_interface *intf,
673 			const struct usb_device_id *id)
674 {
675 	struct usb_device *usbdev = usb_get_dev(interface_to_usbdev(intf));
676 	struct usb_host_interface *interface;
677 	struct usb_endpoint_descriptor *epd;
678 	struct parport_uss720_private *priv;
679 	struct parport *pp;
680 	unsigned char reg;
681 	int ret = -ENODEV;
682 
683 	dev_dbg(&intf->dev, "probe: vendor id 0x%x, device id 0x%x\n",
684 		le16_to_cpu(usbdev->descriptor.idVendor),
685 		le16_to_cpu(usbdev->descriptor.idProduct));
686 
687 	/* our known interfaces have 3 alternate settings */
688 	if (intf->num_altsetting != 3)
689 		goto bail_out_early;
690 
691 	ret = usb_set_interface(usbdev, intf->altsetting->desc.bInterfaceNumber, 2);
692 	dev_dbg(&intf->dev, "set interface result %d\n", ret);
693 
694 	interface = intf->cur_altsetting;
695 
696 	if (interface->desc.bNumEndpoints < 2)
697 		goto bail_out_early;
698 
699 	/*
700 	 * Allocate parport interface
701 	 */
702 	ret = -ENOMEM;
703 	priv = kzalloc_obj(struct parport_uss720_private);
704 	if (!priv)
705 		goto bail_out_early;
706 
707 	priv->pp = NULL;
708 	priv->usbdev = usbdev;
709 	kref_init(&priv->ref_count);
710 	spin_lock_init(&priv->asynclock);
711 	INIT_LIST_HEAD(&priv->asynclist);
712 	pp = parport_register_port(0, PARPORT_IRQ_NONE, PARPORT_DMA_NONE, &parport_uss720_ops);
713 	if (!pp) {
714 		printk(KERN_WARNING "uss720: could not register parport\n");
715 		goto probe_abort;
716 	}
717 
718 	priv->pp = pp;
719 	pp->private_data = priv;
720 	pp->modes = PARPORT_MODE_PCSPP | PARPORT_MODE_TRISTATE | PARPORT_MODE_EPP | PARPORT_MODE_COMPAT;
721 	if (interface->desc.bNumEndpoints >= 3)
722 		pp->modes |= PARPORT_MODE_ECP;
723 	pp->dev = &usbdev->dev;
724 
725 	/* set the USS720 control register to manual mode, no ECP compression, enable all ints */
726 	set_1284_register(pp, 7, 0x00, GFP_KERNEL);
727 	set_1284_register(pp, 6, 0x30, GFP_KERNEL);  /* PS/2 mode */
728 	set_1284_register(pp, 2, 0x0c, GFP_KERNEL);
729 
730 	/* The Belkin F5U002 Rev 2 P80453-B USB parallel port adapter shares the
731 	 * device ID 050d:0002 with some other device that works with this
732 	 * driver, but it itself does not. Detect and handle the bad cable
733 	 * here. */
734 	ret = get_1284_register(pp, 0, &reg, GFP_KERNEL);
735 	dev_dbg(&intf->dev, "reg: %7ph\n", priv->reg);
736 	if (ret < 0) {
737 		priv->pp = NULL;
738 		parport_del_port(pp);
739 		goto probe_abort;
740 	}
741 
742 	ret = usb_find_last_int_in_endpoint(interface, &epd);
743 	if (!ret) {
744 		dev_dbg(&intf->dev, "epaddr %d interval %d\n",
745 				epd->bEndpointAddress, epd->bInterval);
746 	}
747 	parport_announce_port(pp);
748 
749 	usb_set_intfdata(intf, pp);
750 	return 0;
751 
752 probe_abort:
753 	kill_all_async_requests_priv(priv);
754 	kref_put(&priv->ref_count, destroy_priv);
755 	return -ENODEV;
756 
757 bail_out_early:
758 	usb_put_dev(usbdev);
759 	return ret;
760 }
761 
762 static void uss720_disconnect(struct usb_interface *intf)
763 {
764 	struct parport *pp = usb_get_intfdata(intf);
765 	struct parport_uss720_private *priv;
766 
767 	dev_dbg(&intf->dev, "disconnect\n");
768 	usb_set_intfdata(intf, NULL);
769 	if (pp) {
770 		priv = pp->private_data;
771 		priv->pp = NULL;
772 		dev_dbg(&intf->dev, "parport_remove_port\n");
773 		parport_remove_port(pp);
774 		parport_put_port(pp);
775 		kill_all_async_requests_priv(priv);
776 		kref_put(&priv->ref_count, destroy_priv);
777 	}
778 	dev_dbg(&intf->dev, "disconnect done\n");
779 }
780 
781 /* table of cables that work through this driver */
782 static const struct usb_device_id uss720_table[] = {
783 	{ USB_DEVICE(0x047e, 0x1001) }, /* Infowave 901-0030 */
784 	{ USB_DEVICE(0x04b8, 0x0002) }, /* Epson CAEUL0002 ISD-103 */
785 	{ USB_DEVICE(0x04b8, 0x0003) }, /* Epson ISD-101 */
786 	{ USB_DEVICE(0x050d, 0x0002) },
787 	{ USB_DEVICE(0x050d, 0x1202) }, /* Belkin F5U120-PC */
788 	{ USB_DEVICE(0x0557, 0x2001) },
789 	{ USB_DEVICE(0x05ab, 0x0002) }, /* Belkin F5U002 ISD-101 */
790 	{ USB_DEVICE(0x05ab, 0x1001) }, /* Belkin F5U002 P80453-A */
791 	{ USB_DEVICE(0x06c6, 0x0100) }, /* Infowave ISD-103 */
792 	{ USB_DEVICE(0x0729, 0x1284) },
793 	{ USB_DEVICE(0x1293, 0x0002) },
794 	{ }						/* Terminating entry */
795 };
796 
797 MODULE_DEVICE_TABLE (usb, uss720_table);
798 
799 
800 static struct usb_driver uss720_driver = {
801 	.name =		"uss720",
802 	.probe =	uss720_probe,
803 	.disconnect =	uss720_disconnect,
804 	.id_table =	uss720_table,
805 };
806 
807 /* --------------------------------------------------------------------- */
808 
809 MODULE_AUTHOR(DRIVER_AUTHOR);
810 MODULE_DESCRIPTION(DRIVER_DESC);
811 MODULE_LICENSE("GPL");
812 
813 static int __init uss720_init(void)
814 {
815 	int retval;
816 	retval = usb_register(&uss720_driver);
817 	if (retval)
818 		goto out;
819 
820 	printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_DESC "\n");
821 	printk(KERN_INFO KBUILD_MODNAME ": NOTE: this is a special purpose "
822 	       "driver to allow nonstandard\n");
823 	printk(KERN_INFO KBUILD_MODNAME ": protocols (eg. bitbang) over "
824 	       "USS720 usb to parallel cables\n");
825 	printk(KERN_INFO KBUILD_MODNAME ": If you just want to connect to a "
826 	       "printer, use usblp instead\n");
827 out:
828 	return retval;
829 }
830 
831 static void __exit uss720_cleanup(void)
832 {
833 	usb_deregister(&uss720_driver);
834 }
835 
836 module_init(uss720_init);
837 module_exit(uss720_cleanup);
838 
839 /* --------------------------------------------------------------------- */
840