drivers/char/ppdev.c

   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/major.h>
  68 #include <linux/ppdev.h>
  69 #include <linux/smp_lock.h>
  70 #include <linux/uaccess.h>
  71
  72 #define PP_VERSION "ppdev: user-space parallel port driver"
  73 #define CHRDEV "ppdev"
  74
  75 struct pp_struct {
  76         struct pardevice * pdev;
  77         wait_queue_head_t irq_wait;
  78         atomic_t irqc;
  79         unsigned int flags;
  80         int irqresponse;
  81         unsigned char irqctl;
  82         struct ieee1284_info state;
  83         struct ieee1284_info saved_state;
  84         long default_inactivity;
  85 };
  86
  87 /* pp_struct.flags bitfields */
  88 #define PP_CLAIMED    (1<<0)
  89 #define PP_EXCL       (1<<1)
  90
  91 /* Other constants */
  92 #define PP_INTERRUPT_TIMEOUT (10 * HZ) /* 10s */
  93 #define PP_BUFFER_SIZE 1024
  94 #define PARDEVICE_MAX 8
  95
  96 /* ROUND_UP macro from fs/select.c */
  97 #define ROUND_UP(x,y) (((x)+(y)-1)/(y))
  98
  99 static inline void pp_enable_irq (struct pp_struct *pp)
 100 {
 101         struct parport *port = pp->pdev->port;
 102         port->ops->enable_irq (port);
 103 }
 104
 105 static ssize_t pp_read (struct file * file, char __user * buf, size_t count,
 106                         loff_t * ppos)
 107 {
 108         unsigned int minor = iminor(file->f_path.dentry->d_inode);
 109         struct pp_struct *pp = file->private_data;
 110         char * kbuffer;
 111         ssize_t bytes_read = 0;
 112         struct parport *pport;
 113         int mode;
 114
 115         if (!(pp->flags & PP_CLAIMED)) {
 116                 /* Don't have the port claimed */
 117                 printk (KERN_DEBUG CHRDEV "%x: claim the port first\n",
 118                         minor);
 119                 return -EINVAL;
 120         }
 121
 122         /* Trivial case. */
 123         if (count == 0)
 124                 return 0;
 125
 126         kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
 127         if (!kbuffer) {
 128                 return -ENOMEM;
 129         }
 130         pport = pp->pdev->port;
 131         mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
 132
 133         parport_set_timeout (pp->pdev,
 134                              (file->f_flags & O_NONBLOCK) ?
 135                              PARPORT_INACTIVITY_O_NONBLOCK :
 136                              pp->default_inactivity);
 137
 138         while (bytes_read == 0) {
 139                 ssize_t need = min_t(unsigned long, count, PP_BUFFER_SIZE);
 140
 141                 if (mode == IEEE1284_MODE_EPP) {
 142                         /* various specials for EPP mode */
 143                         int flags = 0;
 144                         size_t (*fn)(struct parport *, void *, size_t, int);
 145
 146                         if (pp->flags & PP_W91284PIC) {
 147                                 flags |= PARPORT_W91284PIC;
 148                         }
 149                         if (pp->flags & PP_FASTREAD) {
 150                                 flags |= PARPORT_EPP_FAST;
 151                         }
 152                         if (pport->ieee1284.mode & IEEE1284_ADDR) {
 153                                 fn = pport->ops->epp_read_addr;
 154                         } else {
 155                                 fn = pport->ops->epp_read_data;
 156                         }
 157                         bytes_read = (*fn)(pport, kbuffer, need, flags);
 158                 } else {
 159                         bytes_read = parport_read (pport, kbuffer, need);
 160                 }
 161
 162                 if (bytes_read != 0)
 163                         break;
 164
 165                 if (file->f_flags & O_NONBLOCK) {
 166                         bytes_read = -EAGAIN;
 167                         break;
 168                 }
 169
 170                 if (signal_pending (current)) {
 171                         bytes_read = -ERESTARTSYS;
 172                         break;
 173                 }
 174
 175                 cond_resched();
 176         }
 177
 178         parport_set_timeout (pp->pdev, pp->default_inactivity);
 179
 180         if (bytes_read > 0 && copy_to_user (buf, kbuffer, bytes_read))
 181                 bytes_read = -EFAULT;
 182
 183         kfree (kbuffer);
 184         pp_enable_irq (pp);
 185         return bytes_read;
 186 }
 187
 188 static ssize_t pp_write (struct file * file, const char __user * buf,
 189                          size_t count, loff_t * ppos)
 190 {
 191         unsigned int minor = iminor(file->f_path.dentry->d_inode);
 192         struct pp_struct *pp = file->private_data;
 193         char * kbuffer;
 194         ssize_t bytes_written = 0;
 195         ssize_t wrote;
 196         int mode;
 197         struct parport *pport;
 198
 199         if (!(pp->flags & PP_CLAIMED)) {
 200                 /* Don't have the port claimed */
 201                 printk (KERN_DEBUG CHRDEV "%x: claim the port first\n",
 202                         minor);
 203                 return -EINVAL;
 204         }
 205
 206         kbuffer = kmalloc(min_t(size_t, count, PP_BUFFER_SIZE), GFP_KERNEL);
 207         if (!kbuffer) {
 208                 return -ENOMEM;
 209         }
 210         pport = pp->pdev->port;
 211         mode = pport->ieee1284.mode & ~(IEEE1284_DEVICEID | IEEE1284_ADDR);
 212
 213         parport_set_timeout (pp->pdev,
 214                              (file->f_flags & O_NONBLOCK) ?
 215                              PARPORT_INACTIVITY_O_NONBLOCK :
 216                              pp->default_inactivity);
 217
 218         while (bytes_written < count) {
 219                 ssize_t n = min_t(unsigned long, count - bytes_written, PP_BUFFER_SIZE);
 220
 221                 if (copy_from_user (kbuffer, buf + bytes_written, n)) {
 222                         bytes_written = -EFAULT;
 223                         break;
 224                 }
 225
 226                 if ((pp->flags & PP_FASTWRITE) && (mode == IEEE1284_MODE_EPP)) {
 227                         /* do a fast EPP write */
 228                         if (pport->ieee1284.mode & IEEE1284_ADDR) {
 229                                 wrote = pport->ops->epp_write_addr (pport,
 230                                         kbuffer, n, PARPORT_EPP_FAST);
 231                         } else {
 232                                 wrote = pport->ops->epp_write_data (pport,
 233                                         kbuffer, n, PARPORT_EPP_FAST);
 234                         }
 235                 } else {
 236                         wrote = parport_write (pp->pdev->port, kbuffer, n);
 237                 }
 238
 239                 if (wrote <= 0) {
 240                         if (!bytes_written) {
 241                                 bytes_written = wrote;
 242                         }
 243                         break;
 244                 }
 245
 246                 bytes_written += wrote;
 247
 248                 if (file->f_flags & O_NONBLOCK) {
 249                         if (!bytes_written)
 250                                 bytes_written = -EAGAIN;
 251                         break;
 252                 }
 253
 254                 if (signal_pending (current)) {
 255                         if (!bytes_written) {
 256                                 bytes_written = -EINTR;
 257                         }
 258                         break;
 259                 }
 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 = kmalloc (strlen (CHRDEV) + 3, GFP_KERNEL);
 292         if (name == NULL)
 293                 return -ENOMEM;
 294
 295         sprintf (name, CHRDEV "%x", minor);
 296
 297         port = parport_find_number (minor);
 298         if (!port) {
 299                 printk (KERN_WARNING "%s: no associated port!\n", name);
 300                 kfree (name);
 301                 return -ENXIO;
 302         }
 303
 304         fl = (pp->flags & PP_EXCL) ? PARPORT_FLAG_EXCL : 0;
 305         pdev = parport_register_device (port, name, NULL,
 306                                         NULL, pp_irq, fl, pp);
 307         parport_put_port (port);
 308
 309         if (!pdev) {
 310                 printk (KERN_WARNING "%s: failed to register device!\n", name);
 311                 kfree (name);
 312                 return -ENXIO;
 313         }
 314
 315         pp->pdev = pdev;
 316         printk (KERN_DEBUG "%s: registered pardevice\n", name);
 317         return 0;
 318 }
 319
 320 static enum ieee1284_phase init_phase (int mode)
 321 {
 322         switch (mode & ~(IEEE1284_DEVICEID
 323                          | IEEE1284_ADDR)) {
 324         case IEEE1284_MODE_NIBBLE:
 325         case IEEE1284_MODE_BYTE:
 326                 return IEEE1284_PH_REV_IDLE;
 327         }
 328         return IEEE1284_PH_FWD_IDLE;
 329 }
 330
 331 static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 332 {
 333         unsigned int minor = iminor(file->f_path.dentry->d_inode);
 334         struct pp_struct *pp = file->private_data;
 335         struct parport * port;
 336         void __user *argp = (void __user *)arg;
 337
 338         /* First handle the cases that don't take arguments. */
 339         switch (cmd) {
 340         case PPCLAIM:
 341             {
 342                 struct ieee1284_info *info;
 343                 int ret;
 344
 345                 if (pp->flags & PP_CLAIMED) {
 346                         printk (KERN_DEBUG CHRDEV
 347                                 "%x: you've already got it!\n", minor);
 348                         return -EINVAL;
 349                 }
 350
 351                 /* Deferred device registration. */
 352                 if (!pp->pdev) {
 353                         int err = register_device (minor, pp);
 354                         if (err) {
 355                                 return err;
 356                         }
 357                 }
 358
 359                 ret = parport_claim_or_block (pp->pdev);
 360                 if (ret < 0)
 361                         return ret;
 362
 363                 pp->flags |= PP_CLAIMED;
 364
 365                 /* For interrupt-reporting to work, we need to be
 366                  * informed of each interrupt. */
 367                 pp_enable_irq (pp);
 368
 369                 /* We may need to fix up the state machine. */
 370                 info = &pp->pdev->port->ieee1284;
 371                 pp->saved_state.mode = info->mode;
 372                 pp->saved_state.phase = info->phase;
 373                 info->mode = pp->state.mode;
 374                 info->phase = pp->state.phase;
 375                 pp->default_inactivity = parport_set_timeout (pp->pdev, 0);
 376                 parport_set_timeout (pp->pdev, pp->default_inactivity);
 377
 378                 return 0;
 379             }
 380         case PPEXCL:
 381                 if (pp->pdev) {
 382                         printk (KERN_DEBUG CHRDEV "%x: too late for PPEXCL; "
 383                                 "already registered\n", minor);
 384                         if (pp->flags & PP_EXCL)
 385                                 /* But it's not really an error. */
 386                                 return 0;
 387                         /* There's no chance of making the driver happy. */
 388                         return -EINVAL;
 389                 }
 390
 391                 /* Just remember to register the device exclusively
 392                  * when we finally do the registration. */
 393                 pp->flags |= PP_EXCL;
 394                 return 0;
 395         case PPSETMODE:
 396             {
 397                 int mode;
 398                 if (copy_from_user (&mode, argp, sizeof (mode)))
 399                         return -EFAULT;
 400                 /* FIXME: validate mode */
 401                 pp->state.mode = mode;
 402                 pp->state.phase = init_phase (mode);
 403
 404                 if (pp->flags & PP_CLAIMED) {
 405                         pp->pdev->port->ieee1284.mode = mode;
 406                         pp->pdev->port->ieee1284.phase = pp->state.phase;
 407                 }
 408
 409                 return 0;
 410             }
 411         case PPGETMODE:
 412             {
 413                 int mode;
 414
 415                 if (pp->flags & PP_CLAIMED) {
 416                         mode = pp->pdev->port->ieee1284.mode;
 417                 } else {
 418                         mode = pp->state.mode;
 419                 }
 420                 if (copy_to_user (argp, &mode, sizeof (mode))) {
 421                         return -EFAULT;
 422                 }
 423                 return 0;
 424             }
 425         case PPSETPHASE:
 426             {
 427                 int phase;
 428                 if (copy_from_user (&phase, argp, sizeof (phase))) {
 429                         return -EFAULT;
 430                 }
 431                 /* FIXME: validate phase */
 432                 pp->state.phase = phase;
 433
 434                 if (pp->flags & PP_CLAIMED) {
 435                         pp->pdev->port->ieee1284.phase = phase;
 436                 }
 437
 438                 return 0;
 439             }
 440         case PPGETPHASE:
 441             {
 442                 int phase;
 443
 444                 if (pp->flags & PP_CLAIMED) {
 445                         phase = pp->pdev->port->ieee1284.phase;
 446                 } else {
 447                         phase = pp->state.phase;
 448                 }
 449                 if (copy_to_user (argp, &phase, sizeof (phase))) {
 450                         return -EFAULT;
 451                 }
 452                 return 0;
 453             }
 454         case PPGETMODES:
 455             {
 456                 unsigned int modes;
 457
 458                 port = parport_find_number (minor);
 459                 if (!port)
 460                         return -ENODEV;
 461
 462                 modes = port->modes;
 463                 if (copy_to_user (argp, &modes, sizeof (modes))) {
 464                         return -EFAULT;
 465                 }
 466                 return 0;
 467             }
 468         case PPSETFLAGS:
 469             {
 470                 int uflags;
 471
 472                 if (copy_from_user (&uflags, argp, sizeof (uflags))) {
 473                         return -EFAULT;
 474                 }
 475                 pp->flags &= ~PP_FLAGMASK;
 476                 pp->flags |= (uflags & PP_FLAGMASK);
 477                 return 0;
 478             }
 479         case PPGETFLAGS:
 480             {
 481                 int uflags;
 482
 483                 uflags = pp->flags & PP_FLAGMASK;
 484                 if (copy_to_user (argp, &uflags, sizeof (uflags))) {
 485                         return -EFAULT;
 486                 }
 487                 return 0;
 488             }
 489         }       /* end switch() */
 490
 491         /* Everything else requires the port to be claimed, so check
 492          * that now. */
 493         if ((pp->flags & PP_CLAIMED) == 0) {
 494                 printk (KERN_DEBUG CHRDEV "%x: claim the port first\n",
 495                         minor);
 496                 return -EINVAL;
 497         }
 498
 499         port = pp->pdev->port;
 500         switch (cmd) {
 501                 struct ieee1284_info *info;
 502                 unsigned char reg;
 503                 unsigned char mask;
 504                 int mode;
 505                 int ret;
 506                 struct timeval par_timeout;
 507                 long to_jiffies;
 508
 509         case PPRSTATUS:
 510                 reg = parport_read_status (port);
 511                 if (copy_to_user (argp, &reg, sizeof (reg)))
 512                         return -EFAULT;
 513                 return 0;
 514         case PPRDATA:
 515                 reg = parport_read_data (port);
 516                 if (copy_to_user (argp, &reg, sizeof (reg)))
 517                         return -EFAULT;
 518                 return 0;
 519         case PPRCONTROL:
 520                 reg = parport_read_control (port);
 521                 if (copy_to_user (argp, &reg, sizeof (reg)))
 522                         return -EFAULT;
 523                 return 0;
 524         case PPYIELD:
 525                 parport_yield_blocking (pp->pdev);
 526                 return 0;
 527
 528         case PPRELEASE:
 529                 /* Save the state machine's state. */
 530                 info = &pp->pdev->port->ieee1284;
 531                 pp->state.mode = info->mode;
 532                 pp->state.phase = info->phase;
 533                 info->mode = pp->saved_state.mode;
 534                 info->phase = pp->saved_state.phase;
 535                 parport_release (pp->pdev);
 536                 pp->flags &= ~PP_CLAIMED;
 537                 return 0;
 538
 539         case PPWCONTROL:
 540                 if (copy_from_user (&reg, argp, sizeof (reg)))
 541                         return -EFAULT;
 542                 parport_write_control (port, reg);
 543                 return 0;
 544
 545         case PPWDATA:
 546                 if (copy_from_user (&reg, argp, sizeof (reg)))
 547                         return -EFAULT;
 548                 parport_write_data (port, reg);
 549                 return 0;
 550
 551         case PPFCONTROL:
 552                 if (copy_from_user (&mask, argp,
 553                                     sizeof (mask)))
 554                         return -EFAULT;
 555                 if (copy_from_user (&reg, 1 + (unsigned char __user *) arg,
 556                                     sizeof (reg)))
 557                         return -EFAULT;
 558                 parport_frob_control (port, mask, reg);
 559                 return 0;
 560
 561         case PPDATADIR:
 562                 if (copy_from_user (&mode, argp, sizeof (mode)))
 563                         return -EFAULT;
 564                 if (mode)
 565                         port->ops->data_reverse (port);
 566                 else
 567                         port->ops->data_forward (port);
 568                 return 0;
 569
 570         case PPNEGOT:
 571                 if (copy_from_user (&mode, argp, sizeof (mode)))
 572                         return -EFAULT;
 573                 switch ((ret = parport_negotiate (port, mode))) {
 574                 case 0: break;
 575                 case -1: /* handshake failed, peripheral not IEEE 1284 */
 576                         ret = -EIO;
 577                         break;
 578                 case 1:  /* handshake succeeded, peripheral rejected mode */
 579                         ret = -ENXIO;
 580                         break;
 581                 }
 582                 pp_enable_irq (pp);
 583                 return ret;
 584
 585         case PPWCTLONIRQ:
 586                 if (copy_from_user (&reg, argp, sizeof (reg)))
 587                         return -EFAULT;
 588
 589                 /* Remember what to set the control lines to, for next
 590                  * time we get an interrupt. */
 591                 pp->irqctl = reg;
 592                 pp->irqresponse = 1;
 593                 return 0;
 594
 595         case PPCLRIRQ:
 596                 ret = atomic_read (&pp->irqc);
 597                 if (copy_to_user (argp, &ret, sizeof (ret)))
 598                         return -EFAULT;
 599                 atomic_sub (ret, &pp->irqc);
 600                 return 0;
 601
 602         case PPSETTIME:
 603                 if (copy_from_user (&par_timeout, argp, sizeof(struct timeval))) {
 604                         return -EFAULT;
 605                 }
 606                 /* Convert to jiffies, place in pp->pdev->timeout */
 607                 if ((par_timeout.tv_sec < 0) || (par_timeout.tv_usec < 0)) {
 608                         return -EINVAL;
 609                 }
 610                 to_jiffies = ROUND_UP(par_timeout.tv_usec, 1000000/HZ);
 611                 to_jiffies += par_timeout.tv_sec * (long)HZ;
 612                 if (to_jiffies <= 0) {
 613                         return -EINVAL;
 614                 }
 615                 pp->pdev->timeout = to_jiffies;
 616                 return 0;
 617
 618         case PPGETTIME:
 619                 to_jiffies = pp->pdev->timeout;
 620                 par_timeout.tv_sec = to_jiffies / HZ;
 621                 par_timeout.tv_usec = (to_jiffies % (long)HZ) * (1000000/HZ);
 622                 if (copy_to_user (argp, &par_timeout, sizeof(struct timeval)))
 623                         return -EFAULT;
 624                 return 0;
 625
 626         default:
 627                 printk (KERN_DEBUG CHRDEV "%x: What? (cmd=0x%x)\n", minor,
 628                         cmd);
 629                 return -EINVAL;
 630         }
 631
 632         /* Keep the compiler happy */
 633         return 0;
 634 }
 635
 636 static long pp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 637 {
 638         long ret;
 639         lock_kernel();
 640         ret = pp_do_ioctl(file, cmd, arg);
 641         unlock_kernel();
 642         return ret;
 643 }
 644
 645 static int pp_open (struct inode * inode, struct file * file)
 646 {
 647         unsigned int minor = iminor(inode);
 648         struct pp_struct *pp;
 649
 650         cycle_kernel_lock();
 651         if (minor >= PARPORT_MAX)
 652                 return -ENXIO;
 653
 654         pp = kmalloc (sizeof (struct pp_struct), GFP_KERNEL);
 655         if (!pp)
 656                 return -ENOMEM;
 657
 658         pp->state.mode = IEEE1284_MODE_COMPAT;
 659         pp->state.phase = init_phase (pp->state.mode);
 660         pp->flags = 0;
 661         pp->irqresponse = 0;
 662         atomic_set (&pp->irqc, 0);
 663         init_waitqueue_head (&pp->irq_wait);
 664
 665         /* Defer the actual device registration until the first claim.
 666          * That way, we know whether or not the driver wants to have
 667          * exclusive access to the port (PPEXCL).
 668          */
 669         pp->pdev = NULL;
 670         file->private_data = pp;
 671
 672         return 0;
 673 }
 674
 675 static int pp_release (struct inode * inode, struct file * file)
 676 {
 677         unsigned int minor = iminor(inode);
 678         struct pp_struct *pp = file->private_data;
 679         int compat_negot;
 680
 681         compat_negot = 0;
 682         if (!(pp->flags & PP_CLAIMED) && pp->pdev &&
 683             (pp->state.mode != IEEE1284_MODE_COMPAT)) {
 684                 struct ieee1284_info *info;
 685
 686                 /* parport released, but not in compatibility mode */
 687                 parport_claim_or_block (pp->pdev);
 688                 pp->flags |= PP_CLAIMED;
 689                 info = &pp->pdev->port->ieee1284;
 690                 pp->saved_state.mode = info->mode;
 691                 pp->saved_state.phase = info->phase;
 692                 info->mode = pp->state.mode;
 693                 info->phase = pp->state.phase;
 694                 compat_negot = 1;
 695         } else if ((pp->flags & PP_CLAIMED) && pp->pdev &&
 696             (pp->pdev->port->ieee1284.mode != IEEE1284_MODE_COMPAT)) {
 697                 compat_negot = 2;
 698         }
 699         if (compat_negot) {
 700                 parport_negotiate (pp->pdev->port, IEEE1284_MODE_COMPAT);
 701                 printk (KERN_DEBUG CHRDEV
 702                         "%x: negotiated back to compatibility mode because "
 703                         "user-space forgot\n", minor);
 704         }
 705
 706         if (pp->flags & PP_CLAIMED) {
 707                 struct ieee1284_info *info;
 708
 709                 info = &pp->pdev->port->ieee1284;
 710                 pp->state.mode = info->mode;
 711                 pp->state.phase = info->phase;
 712                 info->mode = pp->saved_state.mode;
 713                 info->phase = pp->saved_state.phase;
 714                 parport_release (pp->pdev);
 715                 if (compat_negot != 1) {
 716                         printk (KERN_DEBUG CHRDEV "%x: released pardevice "
 717                                 "because user-space forgot\n", minor);
 718                 }
 719         }
 720
 721         if (pp->pdev) {
 722                 const char *name = pp->pdev->name;
 723                 parport_unregister_device (pp->pdev);
 724                 kfree (name);
 725                 pp->pdev = NULL;
 726                 printk (KERN_DEBUG CHRDEV "%x: unregistered pardevice\n",
 727                         minor);
 728         }
 729
 730         kfree (pp);
 731
 732         return 0;
 733 }
 734
 735 /* No kernel lock held - fine */
 736 static unsigned int pp_poll (struct file * file, poll_table * wait)
 737 {
 738         struct pp_struct *pp = file->private_data;
 739         unsigned int mask = 0;
 740
 741         poll_wait (file, &pp->irq_wait, wait);
 742         if (atomic_read (&pp->irqc))
 743                 mask |= POLLIN | POLLRDNORM;
 744
 745         return mask;
 746 }
 747
 748 static struct class *ppdev_class;
 749
 750 static const struct file_operations pp_fops = {
 751         .owner          = THIS_MODULE,
 752         .llseek         = no_llseek,
 753         .read           = pp_read,
 754         .write          = pp_write,
 755         .poll           = pp_poll,
 756         .unlocked_ioctl = pp_ioctl,
 757         .open           = pp_open,
 758         .release        = pp_release,
 759 };
 760
 761 static void pp_attach(struct parport *port)
 762 {
 763         device_create(ppdev_class, port->dev, MKDEV(PP_MAJOR, port->number),
 764                       NULL, "parport%d", port->number);
 765 }
 766
 767 static void pp_detach(struct parport *port)
 768 {
 769         device_destroy(ppdev_class, MKDEV(PP_MAJOR, port->number));
 770 }
 771
 772 static struct parport_driver pp_driver = {
 773         .name           = CHRDEV,
 774         .attach         = pp_attach,
 775         .detach         = pp_detach,
 776 };
 777
 778 static int __init ppdev_init (void)
 779 {
 780         int err = 0;
 781
 782         if (register_chrdev (PP_MAJOR, CHRDEV, &pp_fops)) {
 783                 printk (KERN_WARNING CHRDEV ": unable to get major %d\n",
 784                         PP_MAJOR);
 785                 return -EIO;
 786         }
 787         ppdev_class = class_create(THIS_MODULE, CHRDEV);
 788         if (IS_ERR(ppdev_class)) {
 789                 err = PTR_ERR(ppdev_class);
 790                 goto out_chrdev;
 791         }
 792         if (parport_register_driver(&pp_driver)) {
 793                 printk (KERN_WARNING CHRDEV ": unable to register with parport\n");
 794                 goto out_class;
 795         }
 796
 797         printk (KERN_INFO PP_VERSION "\n");
 798         goto out;
 799
 800 out_class:
 801         class_destroy(ppdev_class);
 802 out_chrdev:
 803         unregister_chrdev(PP_MAJOR, CHRDEV);
 804 out:
 805         return err;
 806 }
 807
 808 static void __exit ppdev_cleanup (void)
 809 {
 810         /* Clean up all parport stuff */
 811         parport_unregister_driver(&pp_driver);
 812         class_destroy(ppdev_class);
 813         unregister_chrdev (PP_MAJOR, CHRDEV);
 814 }
 815
 816 module_init(ppdev_init);
 817 module_exit(ppdev_cleanup);
 818
 819 MODULE_LICENSE("GPL");
 820 MODULE_ALIAS_CHARDEV_MAJOR(PP_MAJOR);