drivers/char/tipar.c

   1 /* Hey EMACS -*- linux-c -*-
   2  *
   3  * tipar - low level driver for handling a parallel link cable designed
   4  * for Texas Instruments graphing calculators (http://lpg.ticalc.org).
   5  * A part of the TiLP project.
   6  *
   7  * Copyright (C) 2000-2002, Romain Lievin <roms@lpg.ticalc.org>
   8  * under the terms of the GNU General Public License.
   9  *
  10  * Various fixes & clean-up from the Linux Kernel Mailing List
  11  * (Alan Cox, Richard B. Johnson, Christoph Hellwig).
  12  */
  13
  14 /* This driver should, in theory, work with any parallel port that has an
  15  * appropriate low-level driver; all I/O is done through the parport
  16  * abstraction layer.
  17  *
  18  * If this driver is built into the kernel, you can configure it using the
  19  * kernel command-line.  For example:
  20  *
  21  *      tipar=timeout,delay       (set timeout and delay)
  22  *
  23  * If the driver is loaded as a module, similar functionality is available
  24  * using module parameters.  The equivalent of the above commands would be:
  25  *
  26  *      # insmod tipar timeout=15 delay=10
  27  */
  28
  29 /* COMPATIBILITY WITH OLD KERNELS
  30  *
  31  * Usually, parallel cables were bound to ports at
  32  * particular I/O addresses, as follows:
  33  *
  34  *      tipar0             0x378
  35  *      tipar1             0x278
  36  *      tipar2             0x3bc
  37  *
  38  *
  39  * This driver, by default, binds tipar devices according to parport and
  40  * the minor number.
  41  *
  42  */
  43 #undef DEBUG                            /* change to #define to get debugging
  44                                          * output - for pr_debug() */
  45 #include <linux/config.h>
  46 #include <linux/module.h>
  47 #include <linux/types.h>
  48 #include <linux/errno.h>
  49 #include <linux/kernel.h>
  50 #include <linux/sched.h>
  51 #include <linux/delay.h>
  52 #include <linux/fcntl.h>
  53 #include <linux/fs.h>
  54 #include <linux/init.h>
  55 #include <asm/uaccess.h>
  56 #include <linux/ioport.h>
  57 #include <asm/io.h>
  58 #include <linux/bitops.h>
  59 #include <linux/parport.h>              /* Our code depend on parport */
  60 #include <linux/device.h>
  61
  62 /*
  63  * TI definitions
  64  */
  65 #include <linux/ticable.h>
  66
  67 /*
  68  * Version Information
  69  */
  70 #define DRIVER_VERSION "1.19"
  71 #define DRIVER_AUTHOR  "Romain Lievin <roms@lpg.ticalc.org>"
  72 #define DRIVER_DESC    "Device driver for TI/PC parallel link cables"
  73 #define DRIVER_LICENSE "GPL"
  74
  75 #define VERSION(ver,rel,seq) (((ver)<<16) | ((rel)<<8) | (seq))
  76
  77 /* ----- global variables --------------------------------------------- */
  78
  79 struct tipar_struct {
  80         struct pardevice *dev;  /* Parport device entry */
  81 };
  82
  83 #define PP_NO 3
  84 static struct tipar_struct table[PP_NO];
  85
  86 static int delay = IO_DELAY;    /* inter-bit delay in microseconds */
  87 static int timeout = TIMAXTIME; /* timeout in tenth of seconds     */
  88
  89 static unsigned int tp_count;   /* tipar count */
  90 static unsigned long opened;    /* opened devices */
  91
  92 static struct class *tipar_class;
  93
  94 /* --- macros for parport access -------------------------------------- */
  95
  96 #define r_dtr(x)        (parport_read_data(table[(x)].dev->port))
  97 #define r_str(x)        (parport_read_status(table[(x)].dev->port))
  98 #define w_ctr(x,y)      (parport_write_control(table[(x)].dev->port, (y)))
  99 #define w_dtr(x,y)      (parport_write_data(table[(x)].dev->port, (y)))
 100
 101 /* --- setting states on the D-bus with the right timing: ------------- */
 102
 103 static inline void
 104 outbyte(int value, int minor)
 105 {
 106         w_dtr(minor, value);
 107 }
 108
 109 static inline int
 110 inbyte(int minor)
 111 {
 112         return (r_str(minor));
 113 }
 114
 115 static inline void
 116 init_ti_parallel(int minor)
 117 {
 118         outbyte(3, minor);
 119 }
 120
 121 /* ----- global defines ----------------------------------------------- */
 122
 123 #define START(x) { x = jiffies + (HZ * timeout) / 10; }
 124 #define WAIT(x)  { \
 125   if (time_before((x), jiffies)) return -1; \
 126   if (need_resched()) schedule(); }
 127
 128 /* ----- D-bus bit-banging functions ---------------------------------- */
 129
 130 /* D-bus protocol (45kbit/s max):
 131                     1                 0                      0
 132        _______        ______|______    __________|________    __________
 133 Red  :        ________      |      ____          |        ____
 134        _        ____________|________      ______|__________       _____
 135 White:  ________            |        ______      |          _______
 136 */
 137
 138 /* Try to transmit a byte on the specified port (-1 if error). */
 139 static int
 140 put_ti_parallel(int minor, unsigned char data)
 141 {
 142         unsigned int bit;
 143         unsigned long max;
 144
 145         for (bit = 0; bit < 8; bit++) {
 146                 if (data & 1) {
 147                         outbyte(2, minor);
 148                         START(max);
 149                         do {
 150                                 WAIT(max);
 151                         } while (inbyte(minor) & 0x10);
 152
 153                         outbyte(3, minor);
 154                         START(max);
 155                         do {
 156                                 WAIT(max);
 157                         } while (!(inbyte(minor) & 0x10));
 158                 } else {
 159                         outbyte(1, minor);
 160                         START(max);
 161                         do {
 162                                 WAIT(max);
 163                         } while (inbyte(minor) & 0x20);
 164
 165                         outbyte(3, minor);
 166                         START(max);
 167                         do {
 168                                 WAIT(max);
 169                         } while (!(inbyte(minor) & 0x20));
 170                 }
 171
 172                 data >>= 1;
 173                 udelay(delay);
 174
 175                 if (need_resched())
 176                         schedule();
 177         }
 178
 179         return 0;
 180 }
 181
 182 /* Receive a byte on the specified port or -1 if error. */
 183 static int
 184 get_ti_parallel(int minor)
 185 {
 186         unsigned int bit;
 187         unsigned char v, data = 0;
 188         unsigned long max;
 189
 190         for (bit = 0; bit < 8; bit++) {
 191                 START(max);
 192                 do {
 193                         WAIT(max);
 194                 } while ((v = inbyte(minor) & 0x30) == 0x30);
 195
 196                 if (v == 0x10) {
 197                         data = (data >> 1) | 0x80;
 198                         outbyte(1, minor);
 199                         START(max);
 200                         do {
 201                                 WAIT(max);
 202                         } while (!(inbyte(minor) & 0x20));
 203                         outbyte(3, minor);
 204                 } else {
 205                         data = data >> 1;
 206                         outbyte(2, minor);
 207                         START(max);
 208                         do {
 209                                 WAIT(max);
 210                         } while (!(inbyte(minor) & 0x10));
 211                         outbyte(3, minor);
 212                 }
 213
 214                 udelay(delay);
 215                 if (need_resched())
 216                         schedule();
 217         }
 218
 219         return (int) data;
 220 }
 221
 222 /* Try to detect a parallel link cable on the specified port */
 223 static int
 224 probe_ti_parallel(int minor)
 225 {
 226         int i;
 227         int seq[] = { 0x00, 0x20, 0x10, 0x30 };
 228
 229         for (i = 3; i >= 0; i--) {
 230                 outbyte(3, minor);
 231                 outbyte(i, minor);
 232                 udelay(delay);
 233                 pr_debug("tipar: Probing -> %i: 0x%02x 0x%02x\n", i,
 234                         data & 0x30, seq[i]);
 235                 if ((inbyte(minor) & 0x30) != seq[i]) {
 236                         outbyte(3, minor);
 237                         return -1;
 238                 }
 239         }
 240
 241         outbyte(3, minor);
 242         return 0;
 243 }
 244
 245 /* ----- kernel module functions--------------------------------------- */
 246
 247 static int
 248 tipar_open(struct inode *inode, struct file *file)
 249 {
 250         unsigned int minor = iminor(inode) - TIPAR_MINOR;
 251
 252         if (tp_count == 0 || minor > tp_count - 1)
 253                 return -ENXIO;
 254
 255         if (test_and_set_bit(minor, &opened))
 256                 return -EBUSY;
 257
 258         if (!table[minor].dev) {
 259                 printk(KERN_ERR "%s: NULL device for minor %u\n",
 260                                 __FUNCTION__, minor);
 261                 return -ENXIO;
 262         }
 263         parport_claim_or_block(table[minor].dev);
 264         init_ti_parallel(minor);
 265         parport_release(table[minor].dev);
 266
 267         return nonseekable_open(inode, file);
 268 }
 269
 270 static int
 271 tipar_close(struct inode *inode, struct file *file)
 272 {
 273         unsigned int minor = iminor(inode) - TIPAR_MINOR;
 274
 275         if (minor > tp_count - 1)
 276                 return -ENXIO;
 277
 278         clear_bit(minor, &opened);
 279
 280         return 0;
 281 }
 282
 283 static ssize_t
 284 tipar_write (struct file *file, const char __user *buf, size_t count,
 285                 loff_t * ppos)
 286 {
 287         unsigned int minor = iminor(file->f_dentry->d_inode) - TIPAR_MINOR;
 288         ssize_t n;
 289
 290         parport_claim_or_block(table[minor].dev);
 291
 292         for (n = 0; n < count; n++) {
 293                 unsigned char b;
 294
 295                 if (get_user(b, buf + n)) {
 296                         n = -EFAULT;
 297                         goto out;
 298                 }
 299
 300                 if (put_ti_parallel(minor, b) == -1) {
 301                         init_ti_parallel(minor);
 302                         n = -ETIMEDOUT;
 303                         goto out;
 304                 }
 305         }
 306       out:
 307         parport_release(table[minor].dev);
 308         return n;
 309 }
 310
 311 static ssize_t
 312 tipar_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
 313 {
 314         int b = 0;
 315         unsigned int minor = iminor(file->f_dentry->d_inode) - TIPAR_MINOR;
 316         ssize_t retval = 0;
 317         ssize_t n = 0;
 318
 319         if (count == 0)
 320                 return 0;
 321
 322         parport_claim_or_block(table[minor].dev);
 323
 324         while (n < count) {
 325                 b = get_ti_parallel(minor);
 326                 if (b == -1) {
 327                         init_ti_parallel(minor);
 328                         retval = -ETIMEDOUT;
 329                         goto out;
 330                 } else {
 331                         if (put_user(b, buf + n)) {
 332                                 retval = -EFAULT;
 333                                 break;
 334                         } else
 335                                 retval = ++n;
 336                 }
 337
 338                 /* Non-blocking mode : try again ! */
 339                 if (file->f_flags & O_NONBLOCK) {
 340                         retval = -EAGAIN;
 341                         goto out;
 342                 }
 343
 344                 /* Signal pending, try again ! */
 345                 if (signal_pending(current)) {
 346                         retval = -ERESTARTSYS;
 347                         goto out;
 348                 }
 349
 350                 if (need_resched())
 351                         schedule();
 352         }
 353
 354       out:
 355         parport_release(table[minor].dev);
 356         return retval;
 357 }
 358
 359 static int
 360 tipar_ioctl(struct inode *inode, struct file *file,
 361             unsigned int cmd, unsigned long arg)
 362 {
 363         int retval = 0;
 364
 365         switch (cmd) {
 366         case IOCTL_TIPAR_DELAY:
 367                 delay = (int)arg;    //get_user(delay, &arg);
 368                 break;
 369         case IOCTL_TIPAR_TIMEOUT:
 370                 if (arg != 0)
 371                         timeout = (int)arg;
 372                 else
 373                         retval = -EINVAL;
 374           break;
 375         default:
 376                 retval = -ENOTTY;
 377                 break;
 378         }
 379
 380         return retval;
 381 }
 382
 383 /* ----- kernel module registering ------------------------------------ */
 384
 385 static struct file_operations tipar_fops = {
 386         .owner = THIS_MODULE,
 387         .llseek = no_llseek,
 388         .read = tipar_read,
 389         .write = tipar_write,
 390         .ioctl = tipar_ioctl,
 391         .open = tipar_open,
 392         .release = tipar_close,
 393 };
 394
 395 /* --- initialisation code ------------------------------------- */
 396
 397 #ifndef MODULE
 398 /*      You must set these - there is no sane way to probe for this cable.
 399  *      You can use 'tipar=timeout,delay' to set these now. */
 400 static int __init
 401 tipar_setup(char *str)
 402 {
 403         int ints[3];
 404
 405         str = get_options(str, ARRAY_SIZE(ints), ints);
 406
 407         if (ints[0] > 0) {
 408                 if (ints[1] != 0)
 409                         timeout = ints[1];
 410                 else
 411                         printk(KERN_WARNING "tipar: bad timeout value (0), "
 412                                 "using default value instead");
 413                 if (ints[0] > 1) {
 414                         delay = ints[2];
 415                 }
 416         }
 417
 418         return 1;
 419 }
 420 #endif
 421
 422 /*
 423  * Register our module into parport.
 424  * Pass also 2 callbacks functions to parport: a pre-emptive function and an
 425  * interrupt handler function (unused).
 426  * Display a message such "tipar0: using parport0 (polling)".
 427  */
 428 static int
 429 tipar_register(int nr, struct parport *port)
 430 {
 431         int err = 0;
 432
 433         /* Register our module into parport */
 434         table[nr].dev = parport_register_device(port, "tipar",
 435                                                 NULL, NULL, NULL, 0,
 436                                                 (void *) &table[nr]);
 437
 438         if (table[nr].dev == NULL) {
 439                 err = 1;
 440                 goto out;
 441         }
 442
 443         class_device_create(tipar_class, NULL, MKDEV(TIPAR_MAJOR,
 444                         TIPAR_MINOR + nr), NULL, "par%d", nr);
 445
 446         /* Display informations */
 447         pr_info("tipar%d: using %s (%s)\n", nr, port->name, (port->irq ==
 448                 PARPORT_IRQ_NONE) ? "polling" : "interrupt-driven");
 449
 450         if (probe_ti_parallel(nr) != -1)
 451                 pr_info("tipar%d: link cable found\n", nr);
 452         else
 453                 pr_info("tipar%d: link cable not found\n", nr);
 454
 455         err = 0;
 456
 457 out:
 458         return err;
 459 }
 460
 461 static void
 462 tipar_attach(struct parport *port)
 463 {
 464         if (tp_count == PP_NO) {
 465                 pr_info("tipar: ignoring parallel port (max. %d)\n", PP_NO);
 466                 return;
 467         }
 468
 469         if (!tipar_register(tp_count, port))
 470                 tp_count++;
 471 }
 472
 473 static void
 474 tipar_detach(struct parport *port)
 475 {
 476         /* Nothing to do */
 477 }
 478
 479 static struct parport_driver tipar_driver = {
 480         .name = "tipar",
 481         .attach = tipar_attach,
 482         .detach = tipar_detach,
 483 };
 484
 485 static int __init
 486 tipar_init_module(void)
 487 {
 488         int err = 0;
 489
 490         pr_info("tipar: parallel link cable driver, version %s\n",
 491                 DRIVER_VERSION);
 492
 493         if (register_chrdev(TIPAR_MAJOR, "tipar", &tipar_fops)) {
 494                 printk(KERN_ERR "tipar: unable to get major %d\n", TIPAR_MAJOR);
 495                 err = -EIO;
 496                 goto out;
 497         }
 498
 499         tipar_class = class_create(THIS_MODULE, "ticables");
 500         if (IS_ERR(tipar_class)) {
 501                 err = PTR_ERR(tipar_class);
 502                 goto out_chrdev;
 503         }
 504         if (parport_register_driver(&tipar_driver)) {
 505                 printk(KERN_ERR "tipar: unable to register with parport\n");
 506                 err = -EIO;
 507                 goto out_class;
 508         }
 509
 510         err = 0;
 511         goto out;
 512
 513 out_class:
 514         class_destroy(tipar_class);
 515
 516 out_chrdev:
 517         unregister_chrdev(TIPAR_MAJOR, "tipar");
 518 out:
 519         return err;
 520 }
 521
 522 static void __exit
 523 tipar_cleanup_module(void)
 524 {
 525         unsigned int i;
 526
 527         /* Unregistering module */
 528         parport_unregister_driver(&tipar_driver);
 529
 530         unregister_chrdev(TIPAR_MAJOR, "tipar");
 531
 532         for (i = 0; i < PP_NO; i++) {
 533                 if (table[i].dev == NULL)
 534                         continue;
 535                 parport_unregister_device(table[i].dev);
 536                 class_device_destroy(tipar_class, MKDEV(TIPAR_MAJOR, i));
 537         }
 538         class_destroy(tipar_class);
 539
 540         pr_info("tipar: module unloaded\n");
 541 }
 542
 543 /* --------------------------------------------------------------------- */
 544
 545 __setup("tipar=", tipar_setup);
 546 module_init(tipar_init_module);
 547 module_exit(tipar_cleanup_module);
 548
 549 MODULE_AUTHOR(DRIVER_AUTHOR);
 550 MODULE_DESCRIPTION(DRIVER_DESC);
 551 MODULE_LICENSE(DRIVER_LICENSE);
 552
 553 module_param(timeout, int, 0);
 554 MODULE_PARM_DESC(timeout, "Timeout (default=1.5 seconds)");
 555 module_param(delay, int, 0);
 556 MODULE_PARM_DESC(delay, "Inter-bit delay (default=10 microseconds)");