xref: /linux/drivers/char/ppdev.c (revision 56bbd86257f899ced7ef9c58210dda4edbd40871)
1 /*
2  * linux/drivers/char/ppdev.c
3  *
4  * This is the code behind /dev/parport* -- it allows a user-space
5  * application to use the parport subsystem.
6  *
7  * Copyright (C) 1998-2000, 2002 Tim Waugh <tim@cyberelk.net>
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License
11  * as published by the Free Software Foundation; either version
12  * 2 of the License, or (at your option) any later version.
13  *
14  * A /dev/parportx device node represents an arbitrary device
15  * on port 'x'.  The following operations are possible:
16  *
17  * open		do nothing, set up default IEEE 1284 protocol to be COMPAT
18  * close	release port and unregister device (if necessary)
19  * ioctl
20  *   EXCL	register device exclusively (may fail)
21  *   CLAIM	(register device first time) parport_claim_or_block
22  *   RELEASE	parport_release
23  *   SETMODE	set the IEEE 1284 protocol to use for read/write
24  *   SETPHASE	set the IEEE 1284 phase of a particular mode.  Not to be
25  *              confused with ioctl(fd, SETPHASER, &stun). ;-)
26  *   DATADIR	data_forward / data_reverse
27  *   WDATA	write_data
28  *   RDATA	read_data
29  *   WCONTROL	write_control
30  *   RCONTROL	read_control
31  *   FCONTROL	frob_control
32  *   RSTATUS	read_status
33  *   NEGOT	parport_negotiate
34  *   YIELD	parport_yield_blocking
35  *   WCTLONIRQ	on interrupt, set control lines
36  *   CLRIRQ	clear (and return) interrupt count
37  *   SETTIME	sets device timeout (struct timeval)
38  *   GETTIME	gets device timeout (struct timeval)
39  *   GETMODES	gets hardware supported modes (unsigned int)
40  *   GETMODE	gets the current IEEE1284 mode
41  *   GETPHASE   gets the current IEEE1284 phase
42  *   GETFLAGS   gets current (user-visible) flags
43  *   SETFLAGS   sets current (user-visible) flags
44  * read/write	read or write in current IEEE 1284 protocol
45  * select	wait for interrupt (in readfds)
46  *
47  * Changes:
48  * Added SETTIME/GETTIME ioctl, Fred Barnes, 1999.
49  *
50  * Arnaldo Carvalho de Melo <acme@conectiva.com.br> 2000/08/25
51  * - On error, copy_from_user and copy_to_user do not return -EFAULT,
52  *   They return the positive number of bytes *not* copied due to address
53  *   space errors.
54  *
55  * Added GETMODES/GETMODE/GETPHASE ioctls, Fred Barnes <frmb2@ukc.ac.uk>, 03/01/2001.
56  * Added GETFLAGS/SETFLAGS ioctls, Fred Barnes, 04/2001
57  */
58 
59 #include <linux/module.h>
60 #include <linux/init.h>
61 #include <linux/sched.h>
62 #include <linux/device.h>
63 #include <linux/ioctl.h>
64 #include <linux/parport.h>
65 #include <linux/ctype.h>
66 #include <linux/poll.h>
67 #include <linux/slab.h>
68 #include <linux/major.h>
69 #include <linux/ppdev.h>
70 #include <linux/mutex.h>
71 #include <linux/uaccess.h>
72 #include <linux/compat.h>
73 
74 #define PP_VERSION "ppdev: user-space parallel port driver"
75 #define CHRDEV "ppdev"
76 
77 struct pp_struct {
78 	struct pardevice *pdev;
79 	wait_queue_head_t irq_wait;
80 	atomic_t irqc;
81 	unsigned int flags;
82 	int irqresponse;
83 	unsigned char irqctl;
84 	struct ieee1284_info state;
85 	struct ieee1284_info saved_state;
86 	long default_inactivity;
87 };
88 
89 /* should we use PARDEVICE_MAX here? */
90 static struct device *devices[PARPORT_MAX];
91 
92 /* pp_struct.flags bitfields */
93 #define PP_CLAIMED    (1<<0)
94 #define PP_EXCL       (1<<1)
95 
96 /* Other constants */
97 #define PP_INTERRUPT_TIMEOUT (10 * HZ) /* 10s */
98 #define PP_BUFFER_SIZE 1024
99 #define PARDEVICE_MAX 8
100 
101 /* ROUND_UP macro from fs/select.c */
102 #define ROUND_UP(x,y) (((x)+(y)-1)/(y))
103 
104 static DEFINE_MUTEX(pp_do_mutex);
105 
106 /* define fixed sized ioctl cmd for y2038 migration */
107 #define PPGETTIME32	_IOR(PP_IOCTL, 0x95, s32[2])
108 #define PPSETTIME32	_IOW(PP_IOCTL, 0x96, s32[2])
109 #define PPGETTIME64	_IOR(PP_IOCTL, 0x95, s64[2])
110 #define PPSETTIME64	_IOW(PP_IOCTL, 0x96, s64[2])
111 
112 static inline void pp_enable_irq(struct pp_struct *pp)
113 {
114 	struct parport *port = pp->pdev->port;
115 
116 	port->ops->enable_irq(port);
117 }
118 
119 static ssize_t pp_read(struct file *file, char __user *buf, size_t count,
120 		       loff_t *ppos)
121 {
122 	unsigned int minor = iminor(file_inode(file));
123 	struct pp_struct *pp = file->private_data;
124 	char *kbuffer;
125 	ssize_t bytes_read = 0;
126 	struct parport *pport;
127 	int mode;
128 
129 	if (!(pp->flags & PP_CLAIMED)) {
130 		/* Don't have the port claimed */
131 		pr_debug(CHRDEV "%x: claim the port first\n", minor);
132 		return -EINVAL;
133 	}
134 
135 	/* Trivial case. */
136 	if (count == 0)
137 		return 0;
138 
139 	kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
140 	if (!kbuffer)
141 		return -ENOMEM;
142 	pport = pp->pdev->port;
143 	mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
144 
145 	parport_set_timeout(pp->pdev,
146 			    (file->f_flags & O_NONBLOCK) ?
147 			    PARPORT_INACTIVITY_O_NONBLOCK :
148 			    pp->default_inactivity);
149 
150 	while (bytes_read == 0) {
151 		ssize_t need = min_t(unsigned long, count, PP_BUFFER_SIZE);
152 
153 		if (mode == IEEE1284_MODE_EPP) {
154 			/* various specials for EPP mode */
155 			int flags = 0;
156 			size_t (*fn)(struct parport *, void *, size_t, int);
157 
158 			if (pp->flags & PP_W91284PIC)
159 				flags |= PARPORT_W91284PIC;
160 			if (pp->flags & PP_FASTREAD)
161 				flags |= PARPORT_EPP_FAST;
162 			if (pport->ieee1284.mode & IEEE1284_ADDR)
163 				fn = pport->ops->epp_read_addr;
164 			else
165 				fn = pport->ops->epp_read_data;
166 			bytes_read = (*fn)(pport, kbuffer, need, flags);
167 		} else {
168 			bytes_read = parport_read(pport, kbuffer, need);
169 		}
170 
171 		if (bytes_read != 0)
172 			break;
173 
174 		if (file->f_flags & O_NONBLOCK) {
175 			bytes_read = -EAGAIN;
176 			break;
177 		}
178 
179 		if (signal_pending(current)) {
180 			bytes_read = -ERESTARTSYS;
181 			break;
182 		}
183 
184 		cond_resched();
185 	}
186 
187 	parport_set_timeout(pp->pdev, pp->default_inactivity);
188 
189 	if (bytes_read > 0 && copy_to_user(buf, kbuffer, bytes_read))
190 		bytes_read = -EFAULT;
191 
192 	kfree(kbuffer);
193 	pp_enable_irq(pp);
194 	return bytes_read;
195 }
196 
197 static ssize_t pp_write(struct file *file, const char __user *buf,
198 			size_t count, loff_t *ppos)
199 {
200 	unsigned int minor = iminor(file_inode(file));
201 	struct pp_struct *pp = file->private_data;
202 	char *kbuffer;
203 	ssize_t bytes_written = 0;
204 	ssize_t wrote;
205 	int mode;
206 	struct parport *pport;
207 
208 	if (!(pp->flags & PP_CLAIMED)) {
209 		/* Don't have the port claimed */
210 		pr_debug(CHRDEV "%x: claim the port first\n", minor);
211 		return -EINVAL;
212 	}
213 
214 	kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
215 	if (!kbuffer)
216 		return -ENOMEM;
217 
218 	pport = pp->pdev->port;
219 	mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
220 
221 	parport_set_timeout(pp->pdev,
222 			    (file->f_flags & O_NONBLOCK) ?
223 			    PARPORT_INACTIVITY_O_NONBLOCK :
224 			    pp->default_inactivity);
225 
226 	while (bytes_written < count) {
227 		ssize_t n = min_t(unsigned long, count - bytes_written, PP_BUFFER_SIZE);
228 
229 		if (copy_from_user(kbuffer, buf + bytes_written, n)) {
230 			bytes_written = -EFAULT;
231 			break;
232 		}
233 
234 		if ((pp->flags & PP_FASTWRITE) && (mode == IEEE1284_MODE_EPP)) {
235 			/* do a fast EPP write */
236 			if (pport->ieee1284.mode & IEEE1284_ADDR) {
237 				wrote = pport->ops->epp_write_addr(pport,
238 					kbuffer, n, PARPORT_EPP_FAST);
239 			} else {
240 				wrote = pport->ops->epp_write_data(pport,
241 					kbuffer, n, PARPORT_EPP_FAST);
242 			}
243 		} else {
244 			wrote = parport_write(pp->pdev->port, kbuffer, n);
245 		}
246 
247 		if (wrote <= 0) {
248 			if (!bytes_written)
249 				bytes_written = wrote;
250 			break;
251 		}
252 
253 		bytes_written += wrote;
254 
255 		if (file->f_flags & O_NONBLOCK) {
256 			if (!bytes_written)
257 				bytes_written = -EAGAIN;
258 			break;
259 		}
260 
261 		if (signal_pending(current))
262 			break;
263 
264 		cond_resched();
265 	}
266 
267 	parport_set_timeout(pp->pdev, pp->default_inactivity);
268 
269 	kfree(kbuffer);
270 	pp_enable_irq(pp);
271 	return bytes_written;
272 }
273 
274 static void pp_irq(void *private)
275 {
276 	struct pp_struct *pp = private;
277 
278 	if (pp->irqresponse) {
279 		parport_write_control(pp->pdev->port, pp->irqctl);
280 		pp->irqresponse = 0;
281 	}
282 
283 	atomic_inc(&pp->irqc);
284 	wake_up_interruptible(&pp->irq_wait);
285 }
286 
287 static int register_device(int minor, struct pp_struct *pp)
288 {
289 	struct parport *port;
290 	struct pardevice *pdev = NULL;
291 	char *name;
292 	struct pardev_cb ppdev_cb;
293 
294 	name = kasprintf(GFP_KERNEL, CHRDEV "%x", minor);
295 	if (name == NULL)
296 		return -ENOMEM;
297 
298 	port = parport_find_number(minor);
299 	if (!port) {
300 		pr_warn("%s: no associated port!\n", name);
301 		kfree(name);
302 		return -ENXIO;
303 	}
304 
305 	memset(&ppdev_cb, 0, sizeof(ppdev_cb));
306 	ppdev_cb.irq_func = pp_irq;
307 	ppdev_cb.flags = (pp->flags & PP_EXCL) ? PARPORT_FLAG_EXCL : 0;
308 	ppdev_cb.private = pp;
309 	pdev = parport_register_dev_model(port, name, &ppdev_cb, minor);
310 	parport_put_port(port);
311 	kfree(name);
312 
313 	if (!pdev) {
314 		pr_warn("%s: failed to register device!\n", name);
315 		return -ENXIO;
316 	}
317 
318 	pp->pdev = pdev;
319 	dev_dbg(&pdev->dev, "registered pardevice\n");
320 	return 0;
321 }
322 
323 static enum ieee1284_phase init_phase(int mode)
324 {
325 	switch (mode & ~(IEEE1284_DEVICEID
326 			 | IEEE1284_ADDR)) {
327 	case IEEE1284_MODE_NIBBLE:
328 	case IEEE1284_MODE_BYTE:
329 		return IEEE1284_PH_REV_IDLE;
330 	}
331 	return IEEE1284_PH_FWD_IDLE;
332 }
333 
334 static int pp_set_timeout(struct pardevice *pdev, long tv_sec, int tv_usec)
335 {
336 	long to_jiffies;
337 
338 	if ((tv_sec < 0) || (tv_usec < 0))
339 		return -EINVAL;
340 
341 	to_jiffies = usecs_to_jiffies(tv_usec);
342 	to_jiffies += tv_sec * HZ;
343 	if (to_jiffies <= 0)
344 		return -EINVAL;
345 
346 	pdev->timeout = to_jiffies;
347 	return 0;
348 }
349 
350 static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
351 {
352 	unsigned int minor = iminor(file_inode(file));
353 	struct pp_struct *pp = file->private_data;
354 	struct parport *port;
355 	void __user *argp = (void __user *)arg;
356 
357 	/* First handle the cases that don't take arguments. */
358 	switch (cmd) {
359 	case PPCLAIM:
360 	    {
361 		struct ieee1284_info *info;
362 		int ret;
363 
364 		if (pp->flags & PP_CLAIMED) {
365 			dev_dbg(&pp->pdev->dev, "you've already got it!\n");
366 			return -EINVAL;
367 		}
368 
369 		/* Deferred device registration. */
370 		if (!pp->pdev) {
371 			int err = register_device(minor, pp);
372 
373 			if (err)
374 				return err;
375 		}
376 
377 		ret = parport_claim_or_block(pp->pdev);
378 		if (ret < 0)
379 			return ret;
380 
381 		pp->flags |= PP_CLAIMED;
382 
383 		/* For interrupt-reporting to work, we need to be
384 		 * informed of each interrupt. */
385 		pp_enable_irq(pp);
386 
387 		/* We may need to fix up the state machine. */
388 		info = &pp->pdev->port->ieee1284;
389 		pp->saved_state.mode = info->mode;
390 		pp->saved_state.phase = info->phase;
391 		info->mode = pp->state.mode;
392 		info->phase = pp->state.phase;
393 		pp->default_inactivity = parport_set_timeout(pp->pdev, 0);
394 		parport_set_timeout(pp->pdev, pp->default_inactivity);
395 
396 		return 0;
397 	    }
398 	case PPEXCL:
399 		if (pp->pdev) {
400 			dev_dbg(&pp->pdev->dev,
401 				"too late for PPEXCL; already registered\n");
402 			if (pp->flags & PP_EXCL)
403 				/* But it's not really an error. */
404 				return 0;
405 			/* There's no chance of making the driver happy. */
406 			return -EINVAL;
407 		}
408 
409 		/* Just remember to register the device exclusively
410 		 * when we finally do the registration. */
411 		pp->flags |= PP_EXCL;
412 		return 0;
413 	case PPSETMODE:
414 	    {
415 		int mode;
416 
417 		if (copy_from_user(&mode, argp, sizeof(mode)))
418 			return -EFAULT;
419 		/* FIXME: validate mode */
420 		pp->state.mode = mode;
421 		pp->state.phase = init_phase(mode);
422 
423 		if (pp->flags & PP_CLAIMED) {
424 			pp->pdev->port->ieee1284.mode = mode;
425 			pp->pdev->port->ieee1284.phase = pp->state.phase;
426 		}
427 
428 		return 0;
429 	    }
430 	case PPGETMODE:
431 	    {
432 		int mode;
433 
434 		if (pp->flags & PP_CLAIMED)
435 			mode = pp->pdev->port->ieee1284.mode;
436 		else
437 			mode = pp->state.mode;
438 
439 		if (copy_to_user(argp, &mode, sizeof(mode)))
440 			return -EFAULT;
441 		return 0;
442 	    }
443 	case PPSETPHASE:
444 	    {
445 		int phase;
446 
447 		if (copy_from_user(&phase, argp, sizeof(phase)))
448 			return -EFAULT;
449 
450 		/* FIXME: validate phase */
451 		pp->state.phase = phase;
452 
453 		if (pp->flags & PP_CLAIMED)
454 			pp->pdev->port->ieee1284.phase = phase;
455 
456 		return 0;
457 	    }
458 	case PPGETPHASE:
459 	    {
460 		int phase;
461 
462 		if (pp->flags & PP_CLAIMED)
463 			phase = pp->pdev->port->ieee1284.phase;
464 		else
465 			phase = pp->state.phase;
466 		if (copy_to_user(argp, &phase, sizeof(phase)))
467 			return -EFAULT;
468 		return 0;
469 	    }
470 	case PPGETMODES:
471 	    {
472 		unsigned int modes;
473 
474 		port = parport_find_number(minor);
475 		if (!port)
476 			return -ENODEV;
477 
478 		modes = port->modes;
479 		parport_put_port(port);
480 		if (copy_to_user(argp, &modes, sizeof(modes)))
481 			return -EFAULT;
482 		return 0;
483 	    }
484 	case PPSETFLAGS:
485 	    {
486 		int uflags;
487 
488 		if (copy_from_user(&uflags, argp, sizeof(uflags)))
489 			return -EFAULT;
490 		pp->flags &= ~PP_FLAGMASK;
491 		pp->flags |= (uflags & PP_FLAGMASK);
492 		return 0;
493 	    }
494 	case PPGETFLAGS:
495 	    {
496 		int uflags;
497 
498 		uflags = pp->flags & PP_FLAGMASK;
499 		if (copy_to_user(argp, &uflags, sizeof(uflags)))
500 			return -EFAULT;
501 		return 0;
502 	    }
503 	}	/* end switch() */
504 
505 	/* Everything else requires the port to be claimed, so check
506 	 * that now. */
507 	if ((pp->flags & PP_CLAIMED) == 0) {
508 		pr_debug(CHRDEV "%x: claim the port first\n", minor);
509 		return -EINVAL;
510 	}
511 
512 	port = pp->pdev->port;
513 	switch (cmd) {
514 		struct ieee1284_info *info;
515 		unsigned char reg;
516 		unsigned char mask;
517 		int mode;
518 		s32 time32[2];
519 		s64 time64[2];
520 		struct timespec64 ts;
521 		int ret;
522 
523 	case PPRSTATUS:
524 		reg = parport_read_status(port);
525 		if (copy_to_user(argp, &reg, sizeof(reg)))
526 			return -EFAULT;
527 		return 0;
528 	case PPRDATA:
529 		reg = parport_read_data(port);
530 		if (copy_to_user(argp, &reg, sizeof(reg)))
531 			return -EFAULT;
532 		return 0;
533 	case PPRCONTROL:
534 		reg = parport_read_control(port);
535 		if (copy_to_user(argp, &reg, sizeof(reg)))
536 			return -EFAULT;
537 		return 0;
538 	case PPYIELD:
539 		parport_yield_blocking(pp->pdev);
540 		return 0;
541 
542 	case PPRELEASE:
543 		/* Save the state machine's state. */
544 		info = &pp->pdev->port->ieee1284;
545 		pp->state.mode = info->mode;
546 		pp->state.phase = info->phase;
547 		info->mode = pp->saved_state.mode;
548 		info->phase = pp->saved_state.phase;
549 		parport_release(pp->pdev);
550 		pp->flags &= ~PP_CLAIMED;
551 		return 0;
552 
553 	case PPWCONTROL:
554 		if (copy_from_user(&reg, argp, sizeof(reg)))
555 			return -EFAULT;
556 		parport_write_control(port, reg);
557 		return 0;
558 
559 	case PPWDATA:
560 		if (copy_from_user(&reg, argp, sizeof(reg)))
561 			return -EFAULT;
562 		parport_write_data(port, reg);
563 		return 0;
564 
565 	case PPFCONTROL:
566 		if (copy_from_user(&mask, argp,
567 				   sizeof(mask)))
568 			return -EFAULT;
569 		if (copy_from_user(&reg, 1 + (unsigned char __user *) arg,
570 				   sizeof(reg)))
571 			return -EFAULT;
572 		parport_frob_control(port, mask, reg);
573 		return 0;
574 
575 	case PPDATADIR:
576 		if (copy_from_user(&mode, argp, sizeof(mode)))
577 			return -EFAULT;
578 		if (mode)
579 			port->ops->data_reverse(port);
580 		else
581 			port->ops->data_forward(port);
582 		return 0;
583 
584 	case PPNEGOT:
585 		if (copy_from_user(&mode, argp, sizeof(mode)))
586 			return -EFAULT;
587 		switch ((ret = parport_negotiate(port, mode))) {
588 		case 0: break;
589 		case -1: /* handshake failed, peripheral not IEEE 1284 */
590 			ret = -EIO;
591 			break;
592 		case 1:  /* handshake succeeded, peripheral rejected mode */
593 			ret = -ENXIO;
594 			break;
595 		}
596 		pp_enable_irq(pp);
597 		return ret;
598 
599 	case PPWCTLONIRQ:
600 		if (copy_from_user(&reg, argp, sizeof(reg)))
601 			return -EFAULT;
602 
603 		/* Remember what to set the control lines to, for next
604 		 * time we get an interrupt. */
605 		pp->irqctl = reg;
606 		pp->irqresponse = 1;
607 		return 0;
608 
609 	case PPCLRIRQ:
610 		ret = atomic_read(&pp->irqc);
611 		if (copy_to_user(argp, &ret, sizeof(ret)))
612 			return -EFAULT;
613 		atomic_sub(ret, &pp->irqc);
614 		return 0;
615 
616 	case PPSETTIME32:
617 		if (copy_from_user(time32, argp, sizeof(time32)))
618 			return -EFAULT;
619 
620 		return pp_set_timeout(pp->pdev, time32[0], time32[1]);
621 
622 	case PPSETTIME64:
623 		if (copy_from_user(time64, argp, sizeof(time64)))
624 			return -EFAULT;
625 
626 		return pp_set_timeout(pp->pdev, time64[0], time64[1]);
627 
628 	case PPGETTIME32:
629 		jiffies_to_timespec64(pp->pdev->timeout, &ts);
630 		time32[0] = ts.tv_sec;
631 		time32[1] = ts.tv_nsec / NSEC_PER_USEC;
632 		if ((time32[0] < 0) || (time32[1] < 0))
633 			return -EINVAL;
634 
635 		if (copy_to_user(argp, time32, sizeof(time32)))
636 			return -EFAULT;
637 
638 		return 0;
639 
640 	case PPGETTIME64:
641 		jiffies_to_timespec64(pp->pdev->timeout, &ts);
642 		time64[0] = ts.tv_sec;
643 		time64[1] = ts.tv_nsec / NSEC_PER_USEC;
644 		if ((time64[0] < 0) || (time64[1] < 0))
645 			return -EINVAL;
646 
647 		if (copy_to_user(argp, time64, sizeof(time64)))
648 			return -EFAULT;
649 
650 		return 0;
651 
652 	default:
653 		dev_dbg(&pp->pdev->dev, "What? (cmd=0x%x)\n", cmd);
654 		return -EINVAL;
655 	}
656 
657 	/* Keep the compiler happy */
658 	return 0;
659 }
660 
661 static long pp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
662 {
663 	long ret;
664 
665 	mutex_lock(&pp_do_mutex);
666 	ret = pp_do_ioctl(file, cmd, arg);
667 	mutex_unlock(&pp_do_mutex);
668 	return ret;
669 }
670 
671 #ifdef CONFIG_COMPAT
672 static long pp_compat_ioctl(struct file *file, unsigned int cmd,
673 			    unsigned long arg)
674 {
675 	return pp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
676 }
677 #endif
678 
679 static int pp_open(struct inode *inode, struct file *file)
680 {
681 	unsigned int minor = iminor(inode);
682 	struct pp_struct *pp;
683 
684 	if (minor >= PARPORT_MAX)
685 		return -ENXIO;
686 
687 	pp = kmalloc(sizeof(struct pp_struct), GFP_KERNEL);
688 	if (!pp)
689 		return -ENOMEM;
690 
691 	pp->state.mode = IEEE1284_MODE_COMPAT;
692 	pp->state.phase = init_phase(pp->state.mode);
693 	pp->flags = 0;
694 	pp->irqresponse = 0;
695 	atomic_set(&pp->irqc, 0);
696 	init_waitqueue_head(&pp->irq_wait);
697 
698 	/* Defer the actual device registration until the first claim.
699 	 * That way, we know whether or not the driver wants to have
700 	 * exclusive access to the port (PPEXCL).
701 	 */
702 	pp->pdev = NULL;
703 	file->private_data = pp;
704 
705 	return 0;
706 }
707 
708 static int pp_release(struct inode *inode, struct file *file)
709 {
710 	unsigned int minor = iminor(inode);
711 	struct pp_struct *pp = file->private_data;
712 	int compat_negot;
713 
714 	compat_negot = 0;
715 	if (!(pp->flags & PP_CLAIMED) && pp->pdev &&
716 	    (pp->state.mode != IEEE1284_MODE_COMPAT)) {
717 		struct ieee1284_info *info;
718 
719 		/* parport released, but not in compatibility mode */
720 		parport_claim_or_block(pp->pdev);
721 		pp->flags |= PP_CLAIMED;
722 		info = &pp->pdev->port->ieee1284;
723 		pp->saved_state.mode = info->mode;
724 		pp->saved_state.phase = info->phase;
725 		info->mode = pp->state.mode;
726 		info->phase = pp->state.phase;
727 		compat_negot = 1;
728 	} else if ((pp->flags & PP_CLAIMED) && pp->pdev &&
729 	    (pp->pdev->port->ieee1284.mode != IEEE1284_MODE_COMPAT)) {
730 		compat_negot = 2;
731 	}
732 	if (compat_negot) {
733 		parport_negotiate(pp->pdev->port, IEEE1284_MODE_COMPAT);
734 		dev_dbg(&pp->pdev->dev,
735 			"negotiated back to compatibility mode because user-space forgot\n");
736 	}
737 
738 	if (pp->flags & PP_CLAIMED) {
739 		struct ieee1284_info *info;
740 
741 		info = &pp->pdev->port->ieee1284;
742 		pp->state.mode = info->mode;
743 		pp->state.phase = info->phase;
744 		info->mode = pp->saved_state.mode;
745 		info->phase = pp->saved_state.phase;
746 		parport_release(pp->pdev);
747 		if (compat_negot != 1) {
748 			pr_debug(CHRDEV "%x: released pardevice "
749 				"because user-space forgot\n", minor);
750 		}
751 	}
752 
753 	if (pp->pdev) {
754 		parport_unregister_device(pp->pdev);
755 		pp->pdev = NULL;
756 		pr_debug(CHRDEV "%x: unregistered pardevice\n", minor);
757 	}
758 
759 	kfree(pp);
760 
761 	return 0;
762 }
763 
764 /* No kernel lock held - fine */
765 static unsigned int pp_poll(struct file *file, poll_table *wait)
766 {
767 	struct pp_struct *pp = file->private_data;
768 	unsigned int mask = 0;
769 
770 	poll_wait(file, &pp->irq_wait, wait);
771 	if (atomic_read(&pp->irqc))
772 		mask |= POLLIN | POLLRDNORM;
773 
774 	return mask;
775 }
776 
777 static struct class *ppdev_class;
778 
779 static const struct file_operations pp_fops = {
780 	.owner		= THIS_MODULE,
781 	.llseek		= no_llseek,
782 	.read		= pp_read,
783 	.write		= pp_write,
784 	.poll		= pp_poll,
785 	.unlocked_ioctl	= pp_ioctl,
786 #ifdef CONFIG_COMPAT
787 	.compat_ioctl   = pp_compat_ioctl,
788 #endif
789 	.open		= pp_open,
790 	.release	= pp_release,
791 };
792 
793 static void pp_attach(struct parport *port)
794 {
795 	struct device *ret;
796 
797 	if (devices[port->number])
798 		return;
799 
800 	ret = device_create(ppdev_class, port->dev,
801 			    MKDEV(PP_MAJOR, port->number), NULL,
802 			    "parport%d", port->number);
803 	if (IS_ERR(ret)) {
804 		pr_err("Failed to create device parport%d\n",
805 		       port->number);
806 		return;
807 	}
808 	devices[port->number] = ret;
809 }
810 
811 static void pp_detach(struct parport *port)
812 {
813 	if (!devices[port->number])
814 		return;
815 
816 	device_destroy(ppdev_class, MKDEV(PP_MAJOR, port->number));
817 	devices[port->number] = NULL;
818 }
819 
820 static int pp_probe(struct pardevice *par_dev)
821 {
822 	struct device_driver *drv = par_dev->dev.driver;
823 	int len = strlen(drv->name);
824 
825 	if (strncmp(par_dev->name, drv->name, len))
826 		return -ENODEV;
827 
828 	return 0;
829 }
830 
831 static struct parport_driver pp_driver = {
832 	.name		= CHRDEV,
833 	.probe		= pp_probe,
834 	.match_port	= pp_attach,
835 	.detach		= pp_detach,
836 	.devmodel	= true,
837 };
838 
839 static int __init ppdev_init(void)
840 {
841 	int err = 0;
842 
843 	if (register_chrdev(PP_MAJOR, CHRDEV, &pp_fops)) {
844 		pr_warn(CHRDEV ": unable to get major %d\n", PP_MAJOR);
845 		return -EIO;
846 	}
847 	ppdev_class = class_create(THIS_MODULE, CHRDEV);
848 	if (IS_ERR(ppdev_class)) {
849 		err = PTR_ERR(ppdev_class);
850 		goto out_chrdev;
851 	}
852 	err = parport_register_driver(&pp_driver);
853 	if (err < 0) {
854 		pr_warn(CHRDEV ": unable to register with parport\n");
855 		goto out_class;
856 	}
857 
858 	pr_info(PP_VERSION "\n");
859 	goto out;
860 
861 out_class:
862 	class_destroy(ppdev_class);
863 out_chrdev:
864 	unregister_chrdev(PP_MAJOR, CHRDEV);
865 out:
866 	return err;
867 }
868 
869 static void __exit ppdev_cleanup(void)
870 {
871 	/* Clean up all parport stuff */
872 	parport_unregister_driver(&pp_driver);
873 	class_destroy(ppdev_class);
874 	unregister_chrdev(PP_MAJOR, CHRDEV);
875 }
876 
877 module_init(ppdev_init);
878 module_exit(ppdev_cleanup);
879 
880 MODULE_LICENSE("GPL");
881 MODULE_ALIAS_CHARDEV_MAJOR(PP_MAJOR);
882