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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* 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() */
Linus Torvalds1da177e2005-04-16 15:20:36 -070045#include <linux/module.h>
46#include <linux/types.h>
47#include <linux/errno.h>
48#include <linux/kernel.h>
49#include <linux/sched.h>
50#include <linux/delay.h>
51#include <linux/fcntl.h>
52#include <linux/fs.h>
53#include <linux/init.h>
54#include <asm/uaccess.h>
55#include <linux/ioport.h>
56#include <asm/io.h>
57#include <linux/bitops.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070058#include <linux/parport.h> /* Our code depend on parport */
59#include <linux/device.h>
60
61/*
62 * TI definitions
63 */
64#include <linux/ticable.h>
65
66/*
67 * Version Information
68 */
69#define DRIVER_VERSION "1.19"
70#define DRIVER_AUTHOR "Romain Lievin <roms@lpg.ticalc.org>"
71#define DRIVER_DESC "Device driver for TI/PC parallel link cables"
72#define DRIVER_LICENSE "GPL"
73
74#define VERSION(ver,rel,seq) (((ver)<<16) | ((rel)<<8) | (seq))
75
76/* ----- global variables --------------------------------------------- */
77
78struct tipar_struct {
79 struct pardevice *dev; /* Parport device entry */
80};
81
82#define PP_NO 3
83static struct tipar_struct table[PP_NO];
84
85static int delay = IO_DELAY; /* inter-bit delay in microseconds */
86static int timeout = TIMAXTIME; /* timeout in tenth of seconds */
87
88static unsigned int tp_count; /* tipar count */
89static unsigned long opened; /* opened devices */
90
gregkh@suse.deca8eca62005-03-23 09:53:09 -080091static struct class *tipar_class;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092
93/* --- macros for parport access -------------------------------------- */
94
95#define r_dtr(x) (parport_read_data(table[(x)].dev->port))
96#define r_str(x) (parport_read_status(table[(x)].dev->port))
97#define w_ctr(x,y) (parport_write_control(table[(x)].dev->port, (y)))
98#define w_dtr(x,y) (parport_write_data(table[(x)].dev->port, (y)))
99
100/* --- setting states on the D-bus with the right timing: ------------- */
101
102static inline void
103outbyte(int value, int minor)
104{
105 w_dtr(minor, value);
106}
107
108static inline int
109inbyte(int minor)
110{
111 return (r_str(minor));
112}
113
114static inline void
115init_ti_parallel(int minor)
116{
117 outbyte(3, minor);
118}
119
120/* ----- global defines ----------------------------------------------- */
121
122#define START(x) { x = jiffies + (HZ * timeout) / 10; }
123#define WAIT(x) { \
124 if (time_before((x), jiffies)) return -1; \
125 if (need_resched()) schedule(); }
126
127/* ----- D-bus bit-banging functions ---------------------------------- */
128
129/* D-bus protocol (45kbit/s max):
130 1 0 0
131 _______ ______|______ __________|________ __________
132Red : ________ | ____ | ____
133 _ ____________|________ ______|__________ _____
134White: ________ | ______ | _______
135*/
136
137/* Try to transmit a byte on the specified port (-1 if error). */
138static int
139put_ti_parallel(int minor, unsigned char data)
140{
141 unsigned int bit;
142 unsigned long max;
143
144 for (bit = 0; bit < 8; bit++) {
145 if (data & 1) {
146 outbyte(2, minor);
147 START(max);
148 do {
149 WAIT(max);
150 } while (inbyte(minor) & 0x10);
151
152 outbyte(3, minor);
153 START(max);
154 do {
155 WAIT(max);
156 } while (!(inbyte(minor) & 0x10));
157 } else {
158 outbyte(1, minor);
159 START(max);
160 do {
161 WAIT(max);
162 } while (inbyte(minor) & 0x20);
163
164 outbyte(3, minor);
165 START(max);
166 do {
167 WAIT(max);
168 } while (!(inbyte(minor) & 0x20));
169 }
170
171 data >>= 1;
172 udelay(delay);
173
174 if (need_resched())
175 schedule();
176 }
177
178 return 0;
179}
180
181/* Receive a byte on the specified port or -1 if error. */
182static int
183get_ti_parallel(int minor)
184{
185 unsigned int bit;
186 unsigned char v, data = 0;
187 unsigned long max;
188
189 for (bit = 0; bit < 8; bit++) {
190 START(max);
191 do {
192 WAIT(max);
193 } while ((v = inbyte(minor) & 0x30) == 0x30);
194
195 if (v == 0x10) {
196 data = (data >> 1) | 0x80;
197 outbyte(1, minor);
198 START(max);
199 do {
200 WAIT(max);
201 } while (!(inbyte(minor) & 0x20));
202 outbyte(3, minor);
203 } else {
204 data = data >> 1;
205 outbyte(2, minor);
206 START(max);
207 do {
208 WAIT(max);
209 } while (!(inbyte(minor) & 0x10));
210 outbyte(3, minor);
211 }
212
213 udelay(delay);
214 if (need_resched())
215 schedule();
216 }
217
218 return (int) data;
219}
220
221/* Try to detect a parallel link cable on the specified port */
222static int
223probe_ti_parallel(int minor)
224{
225 int i;
226 int seq[] = { 0x00, 0x20, 0x10, 0x30 };
227
228 for (i = 3; i >= 0; i--) {
229 outbyte(3, minor);
230 outbyte(i, minor);
231 udelay(delay);
232 pr_debug("tipar: Probing -> %i: 0x%02x 0x%02x\n", i,
233 data & 0x30, seq[i]);
234 if ((inbyte(minor) & 0x30) != seq[i]) {
235 outbyte(3, minor);
236 return -1;
237 }
238 }
239
240 outbyte(3, minor);
241 return 0;
242}
243
244/* ----- kernel module functions--------------------------------------- */
245
246static int
247tipar_open(struct inode *inode, struct file *file)
248{
249 unsigned int minor = iminor(inode) - TIPAR_MINOR;
250
Andrew Morton1d308832006-02-11 17:56:05 -0800251 if (tp_count == 0 || minor > tp_count - 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 return -ENXIO;
253
254 if (test_and_set_bit(minor, &opened))
255 return -EBUSY;
256
Andrew Morton1d308832006-02-11 17:56:05 -0800257 if (!table[minor].dev) {
258 printk(KERN_ERR "%s: NULL device for minor %u\n",
259 __FUNCTION__, minor);
260 return -ENXIO;
261 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 parport_claim_or_block(table[minor].dev);
263 init_ti_parallel(minor);
264 parport_release(table[minor].dev);
265
266 return nonseekable_open(inode, file);
267}
268
269static int
270tipar_close(struct inode *inode, struct file *file)
271{
272 unsigned int minor = iminor(inode) - TIPAR_MINOR;
273
274 if (minor > tp_count - 1)
275 return -ENXIO;
276
277 clear_bit(minor, &opened);
278
279 return 0;
280}
281
282static ssize_t
283tipar_write (struct file *file, const char __user *buf, size_t count,
284 loff_t * ppos)
285{
286 unsigned int minor = iminor(file->f_dentry->d_inode) - TIPAR_MINOR;
287 ssize_t n;
288
289 parport_claim_or_block(table[minor].dev);
290
291 for (n = 0; n < count; n++) {
292 unsigned char b;
293
294 if (get_user(b, buf + n)) {
295 n = -EFAULT;
296 goto out;
297 }
298
299 if (put_ti_parallel(minor, b) == -1) {
300 init_ti_parallel(minor);
301 n = -ETIMEDOUT;
302 goto out;
303 }
304 }
305 out:
306 parport_release(table[minor].dev);
307 return n;
308}
309
310static ssize_t
311tipar_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
312{
313 int b = 0;
314 unsigned int minor = iminor(file->f_dentry->d_inode) - TIPAR_MINOR;
315 ssize_t retval = 0;
316 ssize_t n = 0;
317
318 if (count == 0)
319 return 0;
320
321 parport_claim_or_block(table[minor].dev);
322
323 while (n < count) {
324 b = get_ti_parallel(minor);
325 if (b == -1) {
326 init_ti_parallel(minor);
327 retval = -ETIMEDOUT;
328 goto out;
329 } else {
330 if (put_user(b, buf + n)) {
331 retval = -EFAULT;
332 break;
333 } else
334 retval = ++n;
335 }
336
337 /* Non-blocking mode : try again ! */
338 if (file->f_flags & O_NONBLOCK) {
339 retval = -EAGAIN;
340 goto out;
341 }
342
343 /* Signal pending, try again ! */
344 if (signal_pending(current)) {
345 retval = -ERESTARTSYS;
346 goto out;
347 }
348
349 if (need_resched())
350 schedule();
351 }
352
353 out:
354 parport_release(table[minor].dev);
355 return retval;
356}
357
358static int
359tipar_ioctl(struct inode *inode, struct file *file,
360 unsigned int cmd, unsigned long arg)
361{
362 int retval = 0;
363
364 switch (cmd) {
365 case IOCTL_TIPAR_DELAY:
366 delay = (int)arg; //get_user(delay, &arg);
367 break;
368 case IOCTL_TIPAR_TIMEOUT:
369 if (arg != 0)
370 timeout = (int)arg;
371 else
372 retval = -EINVAL;
373 break;
374 default:
375 retval = -ENOTTY;
376 break;
377 }
378
379 return retval;
380}
381
382/* ----- kernel module registering ------------------------------------ */
383
Arjan van de Ven62322d22006-07-03 00:24:21 -0700384static const struct file_operations tipar_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385 .owner = THIS_MODULE,
386 .llseek = no_llseek,
387 .read = tipar_read,
388 .write = tipar_write,
389 .ioctl = tipar_ioctl,
390 .open = tipar_open,
391 .release = tipar_close,
392};
393
394/* --- initialisation code ------------------------------------- */
395
396#ifndef MODULE
397/* You must set these - there is no sane way to probe for this cable.
398 * You can use 'tipar=timeout,delay' to set these now. */
399static int __init
400tipar_setup(char *str)
401{
Luc Van Oostenryck45ae36c2005-06-28 20:44:44 -0700402 int ints[3];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403
404 str = get_options(str, ARRAY_SIZE(ints), ints);
405
406 if (ints[0] > 0) {
407 if (ints[1] != 0)
408 timeout = ints[1];
409 else
410 printk(KERN_WARNING "tipar: bad timeout value (0), "
411 "using default value instead");
412 if (ints[0] > 1) {
413 delay = ints[2];
414 }
415 }
416
417 return 1;
418}
419#endif
420
421/*
422 * Register our module into parport.
423 * Pass also 2 callbacks functions to parport: a pre-emptive function and an
424 * interrupt handler function (unused).
425 * Display a message such "tipar0: using parport0 (polling)".
426 */
427static int
428tipar_register(int nr, struct parport *port)
429{
430 int err = 0;
431
432 /* Register our module into parport */
433 table[nr].dev = parport_register_device(port, "tipar",
434 NULL, NULL, NULL, 0,
435 (void *) &table[nr]);
436
437 if (table[nr].dev == NULL) {
438 err = 1;
439 goto out;
440 }
441
Greg Kroah-Hartman53f46542005-10-27 22:25:43 -0700442 class_device_create(tipar_class, NULL, MKDEV(TIPAR_MAJOR,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443 TIPAR_MINOR + nr), NULL, "par%d", nr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444
445 /* Display informations */
446 pr_info("tipar%d: using %s (%s)\n", nr, port->name, (port->irq ==
447 PARPORT_IRQ_NONE) ? "polling" : "interrupt-driven");
448
449 if (probe_ti_parallel(nr) != -1)
450 pr_info("tipar%d: link cable found\n", nr);
451 else
452 pr_info("tipar%d: link cable not found\n", nr);
453
454 err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456out:
457 return err;
458}
459
460static void
461tipar_attach(struct parport *port)
462{
463 if (tp_count == PP_NO) {
464 pr_info("tipar: ignoring parallel port (max. %d)\n", PP_NO);
465 return;
466 }
467
468 if (!tipar_register(tp_count, port))
469 tp_count++;
470}
471
472static void
473tipar_detach(struct parport *port)
474{
475 /* Nothing to do */
476}
477
478static struct parport_driver tipar_driver = {
479 .name = "tipar",
480 .attach = tipar_attach,
481 .detach = tipar_detach,
482};
483
484static int __init
485tipar_init_module(void)
486{
487 int err = 0;
488
489 pr_info("tipar: parallel link cable driver, version %s\n",
490 DRIVER_VERSION);
491
492 if (register_chrdev(TIPAR_MAJOR, "tipar", &tipar_fops)) {
493 printk(KERN_ERR "tipar: unable to get major %d\n", TIPAR_MAJOR);
494 err = -EIO;
495 goto out;
496 }
497
gregkh@suse.deca8eca62005-03-23 09:53:09 -0800498 tipar_class = class_create(THIS_MODULE, "ticables");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 if (IS_ERR(tipar_class)) {
500 err = PTR_ERR(tipar_class);
501 goto out_chrdev;
502 }
Daniel Drake1ac38362006-04-27 18:39:19 -0700503 if (parport_register_driver(&tipar_driver)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504 printk(KERN_ERR "tipar: unable to register with parport\n");
505 err = -EIO;
Andrew Morton1d308832006-02-11 17:56:05 -0800506 goto out_class;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 }
508
509 err = 0;
510 goto out;
511
Andrew Morton1d308832006-02-11 17:56:05 -0800512out_class:
513 class_destroy(tipar_class);
514
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515out_chrdev:
516 unregister_chrdev(TIPAR_MAJOR, "tipar");
517out:
518 return err;
519}
520
521static void __exit
522tipar_cleanup_module(void)
523{
524 unsigned int i;
525
526 /* Unregistering module */
527 parport_unregister_driver(&tipar_driver);
528
529 unregister_chrdev(TIPAR_MAJOR, "tipar");
530
531 for (i = 0; i < PP_NO; i++) {
532 if (table[i].dev == NULL)
533 continue;
534 parport_unregister_device(table[i].dev);
gregkh@suse.deca8eca62005-03-23 09:53:09 -0800535 class_device_destroy(tipar_class, MKDEV(TIPAR_MAJOR, i));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 }
gregkh@suse.deca8eca62005-03-23 09:53:09 -0800537 class_destroy(tipar_class);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538
539 pr_info("tipar: module unloaded\n");
540}
541
542/* --------------------------------------------------------------------- */
543
544__setup("tipar=", tipar_setup);
545module_init(tipar_init_module);
546module_exit(tipar_cleanup_module);
547
548MODULE_AUTHOR(DRIVER_AUTHOR);
549MODULE_DESCRIPTION(DRIVER_DESC);
550MODULE_LICENSE(DRIVER_LICENSE);
551
552module_param(timeout, int, 0);
553MODULE_PARM_DESC(timeout, "Timeout (default=1.5 seconds)");
554module_param(delay, int, 0);
555MODULE_PARM_DESC(delay, "Inter-bit delay (default=10 microseconds)");