xref: /openbmc/linux/drivers/char/ppdev.c (revision 78700c0a)
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 /* pp_struct.flags bitfields */
90 #define PP_CLAIMED    (1<<0)
91 #define PP_EXCL       (1<<1)
92 
93 /* Other constants */
94 #define PP_INTERRUPT_TIMEOUT (10 * HZ) /* 10s */
95 #define PP_BUFFER_SIZE 1024
96 #define PARDEVICE_MAX 8
97 
98 /* ROUND_UP macro from fs/select.c */
99 #define ROUND_UP(x,y) (((x)+(y)-1)/(y))
100 
101 static DEFINE_MUTEX(pp_do_mutex);
102 
103 /* define fixed sized ioctl cmd for y2038 migration */
104 #define PPGETTIME32	_IOR(PP_IOCTL, 0x95, s32[2])
105 #define PPSETTIME32	_IOW(PP_IOCTL, 0x96, s32[2])
106 #define PPGETTIME64	_IOR(PP_IOCTL, 0x95, s64[2])
107 #define PPSETTIME64	_IOW(PP_IOCTL, 0x96, s64[2])
108 
109 static inline void pp_enable_irq(struct pp_struct *pp)
110 {
111 	struct parport *port = pp->pdev->port;
112 
113 	port->ops->enable_irq(port);
114 }
115 
116 static ssize_t pp_read(struct file *file, char __user *buf, size_t count,
117 		       loff_t *ppos)
118 {
119 	unsigned int minor = iminor(file_inode(file));
120 	struct pp_struct *pp = file->private_data;
121 	char *kbuffer;
122 	ssize_t bytes_read = 0;
123 	struct parport *pport;
124 	int mode;
125 
126 	if (!(pp->flags & PP_CLAIMED)) {
127 		/* Don't have the port claimed */
128 		pr_debug(CHRDEV "%x: claim the port first\n", minor);
129 		return -EINVAL;
130 	}
131 
132 	/* Trivial case. */
133 	if (count == 0)
134 		return 0;
135 
136 	kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
137 	if (!kbuffer)
138 		return -ENOMEM;
139 	pport = pp->pdev->port;
140 	mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
141 
142 	parport_set_timeout(pp->pdev,
143 			    (file->f_flags & O_NONBLOCK) ?
144 			    PARPORT_INACTIVITY_O_NONBLOCK :
145 			    pp->default_inactivity);
146 
147 	while (bytes_read == 0) {
148 		ssize_t need = min_t(unsigned long, count, PP_BUFFER_SIZE);
149 
150 		if (mode == IEEE1284_MODE_EPP) {
151 			/* various specials for EPP mode */
152 			int flags = 0;
153 			size_t (*fn)(struct parport *, void *, size_t, int);
154 
155 			if (pp->flags & PP_W91284PIC)
156 				flags |= PARPORT_W91284PIC;
157 			if (pp->flags & PP_FASTREAD)
158 				flags |= PARPORT_EPP_FAST;
159 			if (pport->ieee1284.mode & IEEE1284_ADDR)
160 				fn = pport->ops->epp_read_addr;
161 			else
162 				fn = pport->ops->epp_read_data;
163 			bytes_read = (*fn)(pport, kbuffer, need, flags);
164 		} else {
165 			bytes_read = parport_read(pport, kbuffer, need);
166 		}
167 
168 		if (bytes_read != 0)
169 			break;
170 
171 		if (file->f_flags & O_NONBLOCK) {
172 			bytes_read = -EAGAIN;
173 			break;
174 		}
175 
176 		if (signal_pending(current)) {
177 			bytes_read = -ERESTARTSYS;
178 			break;
179 		}
180 
181 		cond_resched();
182 	}
183 
184 	parport_set_timeout(pp->pdev, pp->default_inactivity);
185 
186 	if (bytes_read > 0 && copy_to_user(buf, kbuffer, bytes_read))
187 		bytes_read = -EFAULT;
188 
189 	kfree(kbuffer);
190 	pp_enable_irq(pp);
191 	return bytes_read;
192 }
193 
194 static ssize_t pp_write(struct file *file, const char __user *buf,
195 			size_t count, loff_t *ppos)
196 {
197 	unsigned int minor = iminor(file_inode(file));
198 	struct pp_struct *pp = file->private_data;
199 	char *kbuffer;
200 	ssize_t bytes_written = 0;
201 	ssize_t wrote;
202 	int mode;
203 	struct parport *pport;
204 
205 	if (!(pp->flags & PP_CLAIMED)) {
206 		/* Don't have the port claimed */
207 		pr_debug(CHRDEV "%x: claim the port first\n", minor);
208 		return -EINVAL;
209 	}
210 
211 	kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
212 	if (!kbuffer)
213 		return -ENOMEM;
214 
215 	pport = pp->pdev->port;
216 	mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
217 
218 	parport_set_timeout(pp->pdev,
219 			    (file->f_flags & O_NONBLOCK) ?
220 			    PARPORT_INACTIVITY_O_NONBLOCK :
221 			    pp->default_inactivity);
222 
223 	while (bytes_written < count) {
224 		ssize_t n = min_t(unsigned long, count - bytes_written, PP_BUFFER_SIZE);
225 
226 		if (copy_from_user(kbuffer, buf + bytes_written, n)) {
227 			bytes_written = -EFAULT;
228 			break;
229 		}
230 
231 		if ((pp->flags & PP_FASTWRITE) && (mode == IEEE1284_MODE_EPP)) {
232 			/* do a fast EPP write */
233 			if (pport->ieee1284.mode & IEEE1284_ADDR) {
234 				wrote = pport->ops->epp_write_addr(pport,
235 					kbuffer, n, PARPORT_EPP_FAST);
236 			} else {
237 				wrote = pport->ops->epp_write_data(pport,
238 					kbuffer, n, PARPORT_EPP_FAST);
239 			}
240 		} else {
241 			wrote = parport_write(pp->pdev->port, kbuffer, n);
242 		}
243 
244 		if (wrote <= 0) {
245 			if (!bytes_written)
246 				bytes_written = wrote;
247 			break;
248 		}
249 
250 		bytes_written += wrote;
251 
252 		if (file->f_flags & O_NONBLOCK) {
253 			if (!bytes_written)
254 				bytes_written = -EAGAIN;
255 			break;
256 		}
257 
258 		if (signal_pending(current))
259 			break;
260 
261 		cond_resched();
262 	}
263 
264 	parport_set_timeout(pp->pdev, pp->default_inactivity);
265 
266 	kfree(kbuffer);
267 	pp_enable_irq(pp);
268 	return bytes_written;
269 }
270 
271 static void pp_irq(void *private)
272 {
273 	struct pp_struct *pp = private;
274 
275 	if (pp->irqresponse) {
276 		parport_write_control(pp->pdev->port, pp->irqctl);
277 		pp->irqresponse = 0;
278 	}
279 
280 	atomic_inc(&pp->irqc);
281 	wake_up_interruptible(&pp->irq_wait);
282 }
283 
284 static int register_device(int minor, struct pp_struct *pp)
285 {
286 	struct parport *port;
287 	struct pardevice *pdev = NULL;
288 	char *name;
289 	int fl;
290 
291 	name = kasprintf(GFP_KERNEL, CHRDEV "%x", minor);
292 	if (name == NULL)
293 		return -ENOMEM;
294 
295 	port = parport_find_number(minor);
296 	if (!port) {
297 		printk(KERN_WARNING "%s: no associated port!\n", name);
298 		kfree(name);
299 		return -ENXIO;
300 	}
301 
302 	fl = (pp->flags & PP_EXCL) ? PARPORT_FLAG_EXCL : 0;
303 	pdev = parport_register_device(port, name, NULL,
304 				       NULL, pp_irq, fl, pp);
305 	parport_put_port(port);
306 
307 	if (!pdev) {
308 		printk(KERN_WARNING "%s: failed to register device!\n", name);
309 		kfree(name);
310 		return -ENXIO;
311 	}
312 
313 	pp->pdev = pdev;
314 	dev_dbg(&pdev->dev, "registered pardevice\n");
315 	return 0;
316 }
317 
318 static enum ieee1284_phase init_phase(int mode)
319 {
320 	switch (mode & ~(IEEE1284_DEVICEID
321 			 | IEEE1284_ADDR)) {
322 	case IEEE1284_MODE_NIBBLE:
323 	case IEEE1284_MODE_BYTE:
324 		return IEEE1284_PH_REV_IDLE;
325 	}
326 	return IEEE1284_PH_FWD_IDLE;
327 }
328 
329 static int pp_set_timeout(struct pardevice *pdev, long tv_sec, int tv_usec)
330 {
331 	long to_jiffies;
332 
333 	if ((tv_sec < 0) || (tv_usec < 0))
334 		return -EINVAL;
335 
336 	to_jiffies = usecs_to_jiffies(tv_usec);
337 	to_jiffies += tv_sec * HZ;
338 	if (to_jiffies <= 0)
339 		return -EINVAL;
340 
341 	pdev->timeout = to_jiffies;
342 	return 0;
343 }
344 
345 static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
346 {
347 	unsigned int minor = iminor(file_inode(file));
348 	struct pp_struct *pp = file->private_data;
349 	struct parport *port;
350 	void __user *argp = (void __user *)arg;
351 
352 	/* First handle the cases that don't take arguments. */
353 	switch (cmd) {
354 	case PPCLAIM:
355 	    {
356 		struct ieee1284_info *info;
357 		int ret;
358 
359 		if (pp->flags & PP_CLAIMED) {
360 			dev_dbg(&pp->pdev->dev, "you've already got it!\n");
361 			return -EINVAL;
362 		}
363 
364 		/* Deferred device registration. */
365 		if (!pp->pdev) {
366 			int err = register_device(minor, pp);
367 
368 			if (err)
369 				return err;
370 		}
371 
372 		ret = parport_claim_or_block(pp->pdev);
373 		if (ret < 0)
374 			return ret;
375 
376 		pp->flags |= PP_CLAIMED;
377 
378 		/* For interrupt-reporting to work, we need to be
379 		 * informed of each interrupt. */
380 		pp_enable_irq(pp);
381 
382 		/* We may need to fix up the state machine. */
383 		info = &pp->pdev->port->ieee1284;
384 		pp->saved_state.mode = info->mode;
385 		pp->saved_state.phase = info->phase;
386 		info->mode = pp->state.mode;
387 		info->phase = pp->state.phase;
388 		pp->default_inactivity = parport_set_timeout(pp->pdev, 0);
389 		parport_set_timeout(pp->pdev, pp->default_inactivity);
390 
391 		return 0;
392 	    }
393 	case PPEXCL:
394 		if (pp->pdev) {
395 			dev_dbg(&pp->pdev->dev,
396 				"too late for PPEXCL; already registered\n");
397 			if (pp->flags & PP_EXCL)
398 				/* But it's not really an error. */
399 				return 0;
400 			/* There's no chance of making the driver happy. */
401 			return -EINVAL;
402 		}
403 
404 		/* Just remember to register the device exclusively
405 		 * when we finally do the registration. */
406 		pp->flags |= PP_EXCL;
407 		return 0;
408 	case PPSETMODE:
409 	    {
410 		int mode;
411 
412 		if (copy_from_user(&mode, argp, sizeof(mode)))
413 			return -EFAULT;
414 		/* FIXME: validate mode */
415 		pp->state.mode = mode;
416 		pp->state.phase = init_phase(mode);
417 
418 		if (pp->flags & PP_CLAIMED) {
419 			pp->pdev->port->ieee1284.mode = mode;
420 			pp->pdev->port->ieee1284.phase = pp->state.phase;
421 		}
422 
423 		return 0;
424 	    }
425 	case PPGETMODE:
426 	    {
427 		int mode;
428 
429 		if (pp->flags & PP_CLAIMED)
430 			mode = pp->pdev->port->ieee1284.mode;
431 		else
432 			mode = pp->state.mode;
433 
434 		if (copy_to_user(argp, &mode, sizeof(mode)))
435 			return -EFAULT;
436 		return 0;
437 	    }
438 	case PPSETPHASE:
439 	    {
440 		int phase;
441 
442 		if (copy_from_user(&phase, argp, sizeof(phase)))
443 			return -EFAULT;
444 
445 		/* FIXME: validate phase */
446 		pp->state.phase = phase;
447 
448 		if (pp->flags & PP_CLAIMED)
449 			pp->pdev->port->ieee1284.phase = phase;
450 
451 		return 0;
452 	    }
453 	case PPGETPHASE:
454 	    {
455 		int phase;
456 
457 		if (pp->flags & PP_CLAIMED)
458 			phase = pp->pdev->port->ieee1284.phase;
459 		else
460 			phase = pp->state.phase;
461 		if (copy_to_user(argp, &phase, sizeof(phase)))
462 			return -EFAULT;
463 		return 0;
464 	    }
465 	case PPGETMODES:
466 	    {
467 		unsigned int modes;
468 
469 		port = parport_find_number(minor);
470 		if (!port)
471 			return -ENODEV;
472 
473 		modes = port->modes;
474 		parport_put_port(port);
475 		if (copy_to_user(argp, &modes, sizeof(modes)))
476 			return -EFAULT;
477 		return 0;
478 	    }
479 	case PPSETFLAGS:
480 	    {
481 		int uflags;
482 
483 		if (copy_from_user(&uflags, argp, sizeof(uflags)))
484 			return -EFAULT;
485 		pp->flags &= ~PP_FLAGMASK;
486 		pp->flags |= (uflags & PP_FLAGMASK);
487 		return 0;
488 	    }
489 	case PPGETFLAGS:
490 	    {
491 		int uflags;
492 
493 		uflags = pp->flags & PP_FLAGMASK;
494 		if (copy_to_user(argp, &uflags, sizeof(uflags)))
495 			return -EFAULT;
496 		return 0;
497 	    }
498 	}	/* end switch() */
499 
500 	/* Everything else requires the port to be claimed, so check
501 	 * that now. */
502 	if ((pp->flags & PP_CLAIMED) == 0) {
503 		pr_debug(CHRDEV "%x: claim the port first\n", minor);
504 		return -EINVAL;
505 	}
506 
507 	port = pp->pdev->port;
508 	switch (cmd) {
509 		struct ieee1284_info *info;
510 		unsigned char reg;
511 		unsigned char mask;
512 		int mode;
513 		s32 time32[2];
514 		s64 time64[2];
515 		struct timespec64 ts;
516 		int ret;
517 
518 	case PPRSTATUS:
519 		reg = parport_read_status(port);
520 		if (copy_to_user(argp, &reg, sizeof(reg)))
521 			return -EFAULT;
522 		return 0;
523 	case PPRDATA:
524 		reg = parport_read_data(port);
525 		if (copy_to_user(argp, &reg, sizeof(reg)))
526 			return -EFAULT;
527 		return 0;
528 	case PPRCONTROL:
529 		reg = parport_read_control(port);
530 		if (copy_to_user(argp, &reg, sizeof(reg)))
531 			return -EFAULT;
532 		return 0;
533 	case PPYIELD:
534 		parport_yield_blocking(pp->pdev);
535 		return 0;
536 
537 	case PPRELEASE:
538 		/* Save the state machine's state. */
539 		info = &pp->pdev->port->ieee1284;
540 		pp->state.mode = info->mode;
541 		pp->state.phase = info->phase;
542 		info->mode = pp->saved_state.mode;
543 		info->phase = pp->saved_state.phase;
544 		parport_release(pp->pdev);
545 		pp->flags &= ~PP_CLAIMED;
546 		return 0;
547 
548 	case PPWCONTROL:
549 		if (copy_from_user(&reg, argp, sizeof(reg)))
550 			return -EFAULT;
551 		parport_write_control(port, reg);
552 		return 0;
553 
554 	case PPWDATA:
555 		if (copy_from_user(&reg, argp, sizeof(reg)))
556 			return -EFAULT;
557 		parport_write_data(port, reg);
558 		return 0;
559 
560 	case PPFCONTROL:
561 		if (copy_from_user(&mask, argp,
562 				   sizeof(mask)))
563 			return -EFAULT;
564 		if (copy_from_user(&reg, 1 + (unsigned char __user *) arg,
565 				   sizeof(reg)))
566 			return -EFAULT;
567 		parport_frob_control(port, mask, reg);
568 		return 0;
569 
570 	case PPDATADIR:
571 		if (copy_from_user(&mode, argp, sizeof(mode)))
572 			return -EFAULT;
573 		if (mode)
574 			port->ops->data_reverse(port);
575 		else
576 			port->ops->data_forward(port);
577 		return 0;
578 
579 	case PPNEGOT:
580 		if (copy_from_user(&mode, argp, sizeof(mode)))
581 			return -EFAULT;
582 		switch ((ret = parport_negotiate(port, mode))) {
583 		case 0: break;
584 		case -1: /* handshake failed, peripheral not IEEE 1284 */
585 			ret = -EIO;
586 			break;
587 		case 1:  /* handshake succeeded, peripheral rejected mode */
588 			ret = -ENXIO;
589 			break;
590 		}
591 		pp_enable_irq(pp);
592 		return ret;
593 
594 	case PPWCTLONIRQ:
595 		if (copy_from_user(&reg, argp, sizeof(reg)))
596 			return -EFAULT;
597 
598 		/* Remember what to set the control lines to, for next
599 		 * time we get an interrupt. */
600 		pp->irqctl = reg;
601 		pp->irqresponse = 1;
602 		return 0;
603 
604 	case PPCLRIRQ:
605 		ret = atomic_read(&pp->irqc);
606 		if (copy_to_user(argp, &ret, sizeof(ret)))
607 			return -EFAULT;
608 		atomic_sub(ret, &pp->irqc);
609 		return 0;
610 
611 	case PPSETTIME32:
612 		if (copy_from_user(time32, argp, sizeof(time32)))
613 			return -EFAULT;
614 
615 		return pp_set_timeout(pp->pdev, time32[0], time32[1]);
616 
617 	case PPSETTIME64:
618 		if (copy_from_user(time64, argp, sizeof(time64)))
619 			return -EFAULT;
620 
621 		return pp_set_timeout(pp->pdev, time64[0], time64[1]);
622 
623 	case PPGETTIME32:
624 		jiffies_to_timespec64(pp->pdev->timeout, &ts);
625 		time32[0] = ts.tv_sec;
626 		time32[1] = ts.tv_nsec / NSEC_PER_USEC;
627 		if ((time32[0] < 0) || (time32[1] < 0))
628 			return -EINVAL;
629 
630 		if (copy_to_user(argp, time32, sizeof(time32)))
631 			return -EFAULT;
632 
633 		return 0;
634 
635 	case PPGETTIME64:
636 		jiffies_to_timespec64(pp->pdev->timeout, &ts);
637 		time64[0] = ts.tv_sec;
638 		time64[1] = ts.tv_nsec / NSEC_PER_USEC;
639 		if ((time64[0] < 0) || (time64[1] < 0))
640 			return -EINVAL;
641 
642 		if (copy_to_user(argp, time64, sizeof(time64)))
643 			return -EFAULT;
644 
645 		return 0;
646 
647 	default:
648 		dev_dbg(&pp->pdev->dev, "What? (cmd=0x%x)\n", cmd);
649 		return -EINVAL;
650 	}
651 
652 	/* Keep the compiler happy */
653 	return 0;
654 }
655 
656 static long pp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
657 {
658 	long ret;
659 
660 	mutex_lock(&pp_do_mutex);
661 	ret = pp_do_ioctl(file, cmd, arg);
662 	mutex_unlock(&pp_do_mutex);
663 	return ret;
664 }
665 
666 #ifdef CONFIG_COMPAT
667 static long pp_compat_ioctl(struct file *file, unsigned int cmd,
668 			    unsigned long arg)
669 {
670 	return pp_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
671 }
672 #endif
673 
674 static int pp_open(struct inode *inode, struct file *file)
675 {
676 	unsigned int minor = iminor(inode);
677 	struct pp_struct *pp;
678 
679 	if (minor >= PARPORT_MAX)
680 		return -ENXIO;
681 
682 	pp = kmalloc(sizeof(struct pp_struct), GFP_KERNEL);
683 	if (!pp)
684 		return -ENOMEM;
685 
686 	pp->state.mode = IEEE1284_MODE_COMPAT;
687 	pp->state.phase = init_phase(pp->state.mode);
688 	pp->flags = 0;
689 	pp->irqresponse = 0;
690 	atomic_set(&pp->irqc, 0);
691 	init_waitqueue_head(&pp->irq_wait);
692 
693 	/* Defer the actual device registration until the first claim.
694 	 * That way, we know whether or not the driver wants to have
695 	 * exclusive access to the port (PPEXCL).
696 	 */
697 	pp->pdev = NULL;
698 	file->private_data = pp;
699 
700 	return 0;
701 }
702 
703 static int pp_release(struct inode *inode, struct file *file)
704 {
705 	unsigned int minor = iminor(inode);
706 	struct pp_struct *pp = file->private_data;
707 	int compat_negot;
708 
709 	compat_negot = 0;
710 	if (!(pp->flags & PP_CLAIMED) && pp->pdev &&
711 	    (pp->state.mode != IEEE1284_MODE_COMPAT)) {
712 		struct ieee1284_info *info;
713 
714 		/* parport released, but not in compatibility mode */
715 		parport_claim_or_block(pp->pdev);
716 		pp->flags |= PP_CLAIMED;
717 		info = &pp->pdev->port->ieee1284;
718 		pp->saved_state.mode = info->mode;
719 		pp->saved_state.phase = info->phase;
720 		info->mode = pp->state.mode;
721 		info->phase = pp->state.phase;
722 		compat_negot = 1;
723 	} else if ((pp->flags & PP_CLAIMED) && pp->pdev &&
724 	    (pp->pdev->port->ieee1284.mode != IEEE1284_MODE_COMPAT)) {
725 		compat_negot = 2;
726 	}
727 	if (compat_negot) {
728 		parport_negotiate(pp->pdev->port, IEEE1284_MODE_COMPAT);
729 		dev_dbg(&pp->pdev->dev,
730 			"negotiated back to compatibility mode because user-space forgot\n");
731 	}
732 
733 	if (pp->flags & PP_CLAIMED) {
734 		struct ieee1284_info *info;
735 
736 		info = &pp->pdev->port->ieee1284;
737 		pp->state.mode = info->mode;
738 		pp->state.phase = info->phase;
739 		info->mode = pp->saved_state.mode;
740 		info->phase = pp->saved_state.phase;
741 		parport_release(pp->pdev);
742 		if (compat_negot != 1) {
743 			pr_debug(CHRDEV "%x: released pardevice "
744 				"because user-space forgot\n", minor);
745 		}
746 	}
747 
748 	if (pp->pdev) {
749 		const char *name = pp->pdev->name;
750 
751 		parport_unregister_device(pp->pdev);
752 		kfree(name);
753 		pp->pdev = NULL;
754 		pr_debug(CHRDEV "%x: unregistered pardevice\n", minor);
755 	}
756 
757 	kfree(pp);
758 
759 	return 0;
760 }
761 
762 /* No kernel lock held - fine */
763 static unsigned int pp_poll(struct file *file, poll_table *wait)
764 {
765 	struct pp_struct *pp = file->private_data;
766 	unsigned int mask = 0;
767 
768 	poll_wait(file, &pp->irq_wait, wait);
769 	if (atomic_read(&pp->irqc))
770 		mask |= POLLIN | POLLRDNORM;
771 
772 	return mask;
773 }
774 
775 static struct class *ppdev_class;
776 
777 static const struct file_operations pp_fops = {
778 	.owner		= THIS_MODULE,
779 	.llseek		= no_llseek,
780 	.read		= pp_read,
781 	.write		= pp_write,
782 	.poll		= pp_poll,
783 	.unlocked_ioctl	= pp_ioctl,
784 #ifdef CONFIG_COMPAT
785 	.compat_ioctl   = pp_compat_ioctl,
786 #endif
787 	.open		= pp_open,
788 	.release	= pp_release,
789 };
790 
791 static void pp_attach(struct parport *port)
792 {
793 	device_create(ppdev_class, port->dev, MKDEV(PP_MAJOR, port->number),
794 		      NULL, "parport%d", port->number);
795 }
796 
797 static void pp_detach(struct parport *port)
798 {
799 	device_destroy(ppdev_class, MKDEV(PP_MAJOR, port->number));
800 }
801 
802 static struct parport_driver pp_driver = {
803 	.name		= CHRDEV,
804 	.attach		= pp_attach,
805 	.detach		= pp_detach,
806 };
807 
808 static int __init ppdev_init(void)
809 {
810 	int err = 0;
811 
812 	if (register_chrdev(PP_MAJOR, CHRDEV, &pp_fops)) {
813 		printk(KERN_WARNING CHRDEV ": unable to get major %d\n",
814 		       PP_MAJOR);
815 		return -EIO;
816 	}
817 	ppdev_class = class_create(THIS_MODULE, CHRDEV);
818 	if (IS_ERR(ppdev_class)) {
819 		err = PTR_ERR(ppdev_class);
820 		goto out_chrdev;
821 	}
822 	err = parport_register_driver(&pp_driver);
823 	if (err < 0) {
824 		printk(KERN_WARNING CHRDEV ": unable to register with parport\n");
825 		goto out_class;
826 	}
827 
828 	printk(KERN_INFO PP_VERSION "\n");
829 	goto out;
830 
831 out_class:
832 	class_destroy(ppdev_class);
833 out_chrdev:
834 	unregister_chrdev(PP_MAJOR, CHRDEV);
835 out:
836 	return err;
837 }
838 
839 static void __exit ppdev_cleanup(void)
840 {
841 	/* Clean up all parport stuff */
842 	parport_unregister_driver(&pp_driver);
843 	class_destroy(ppdev_class);
844 	unregister_chrdev(PP_MAJOR, CHRDEV);
845 }
846 
847 module_init(ppdev_init);
848 module_exit(ppdev_cleanup);
849 
850 MODULE_LICENSE("GPL");
851 MODULE_ALIAS_CHARDEV_MAJOR(PP_MAJOR);
852