blob: ea35ab2c9909490bb490bb51eae47d39c31661b3 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * DS1286 Real Time Clock interface for Linux
3 *
4 * Copyright (C) 1998, 1999, 2000 Ralf Baechle
5 *
6 * Based on code written by Paul Gortmaker.
7 *
8 * This driver allows use of the real time clock (built into nearly all
9 * computers) from user space. It exports the /dev/rtc interface supporting
10 * various ioctl() and also the /proc/rtc pseudo-file for status
11 * information.
12 *
13 * The ioctls can be used to set the interrupt behaviour and generation rate
14 * from the RTC via IRQ 8. Then the /dev/rtc interface can be used to make
15 * use of these timer interrupts, be they interval or alarm based.
16 *
17 * The /dev/rtc interface will block on reads until an interrupt has been
18 * received. If a RTC interrupt has already happened, it will output an
19 * unsigned long and then block. The output value contains the interrupt
20 * status in the low byte and the number of interrupts since the last read
21 * in the remaining high bytes. The /dev/rtc interface can also be used with
22 * the select(2) call.
23 *
24 * This program is free software; you can redistribute it and/or modify it
25 * under the terms of the GNU General Public License as published by the
26 * Free Software Foundation; either version 2 of the License, or (at your
27 * option) any later version.
28 */
29#include <linux/ds1286.h>
30#include <linux/types.h>
31#include <linux/errno.h>
32#include <linux/miscdevice.h>
33#include <linux/slab.h>
34#include <linux/ioport.h>
35#include <linux/fcntl.h>
36#include <linux/init.h>
37#include <linux/poll.h>
38#include <linux/rtc.h>
39#include <linux/spinlock.h>
40#include <linux/bcd.h>
41#include <linux/proc_fs.h>
Julia Lawallac0e4b72008-04-30 00:53:58 -070042#include <linux/jiffies.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070043
44#include <asm/uaccess.h>
45#include <asm/system.h>
46
47#define DS1286_VERSION "1.0"
48
49/*
50 * We sponge a minor off of the misc major. No need slurping
51 * up another valuable major dev number for this. If you add
52 * an ioctl, make sure you don't conflict with SPARC's RTC
53 * ioctls.
54 */
55
56static DECLARE_WAIT_QUEUE_HEAD(ds1286_wait);
57
58static ssize_t ds1286_read(struct file *file, char *buf,
59 size_t count, loff_t *ppos);
60
61static int ds1286_ioctl(struct inode *inode, struct file *file,
62 unsigned int cmd, unsigned long arg);
63
64static unsigned int ds1286_poll(struct file *file, poll_table *wait);
65
66static void ds1286_get_alm_time (struct rtc_time *alm_tm);
67static void ds1286_get_time(struct rtc_time *rtc_tm);
68static int ds1286_set_time(struct rtc_time *rtc_tm);
69
70static inline unsigned char ds1286_is_updating(void);
71
72static DEFINE_SPINLOCK(ds1286_lock);
73
74static int ds1286_read_proc(char *page, char **start, off_t off,
75 int count, int *eof, void *data);
76
77/*
78 * Bits in rtc_status. (7 bits of room for future expansion)
79 */
80
81#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
82#define RTC_TIMER_ON 0x02 /* missed irq timer active */
83
84static unsigned char ds1286_status; /* bitmapped status byte. */
85
86static unsigned char days_in_mo[] = {
87 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
88};
89
90/*
91 * Now all the various file operations that we export.
92 */
93
94static ssize_t ds1286_read(struct file *file, char *buf,
95 size_t count, loff_t *ppos)
96{
97 return -EIO;
98}
99
100static int ds1286_ioctl(struct inode *inode, struct file *file,
101 unsigned int cmd, unsigned long arg)
102{
103 struct rtc_time wtime;
104
105 switch (cmd) {
106 case RTC_AIE_OFF: /* Mask alarm int. enab. bit */
107 {
Alexey Dobriyanc53421b2006-09-30 23:27:37 -0700108 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 unsigned char val;
110
111 if (!capable(CAP_SYS_TIME))
112 return -EACCES;
113
114 spin_lock_irqsave(&ds1286_lock, flags);
115 val = rtc_read(RTC_CMD);
116 val |= RTC_TDM;
117 rtc_write(val, RTC_CMD);
118 spin_unlock_irqrestore(&ds1286_lock, flags);
119
120 return 0;
121 }
122 case RTC_AIE_ON: /* Allow alarm interrupts. */
123 {
Alexey Dobriyanc53421b2006-09-30 23:27:37 -0700124 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 unsigned char val;
126
127 if (!capable(CAP_SYS_TIME))
128 return -EACCES;
129
130 spin_lock_irqsave(&ds1286_lock, flags);
131 val = rtc_read(RTC_CMD);
132 val &= ~RTC_TDM;
133 rtc_write(val, RTC_CMD);
134 spin_unlock_irqrestore(&ds1286_lock, flags);
135
136 return 0;
137 }
138 case RTC_WIE_OFF: /* Mask watchdog int. enab. bit */
139 {
Alexey Dobriyanc53421b2006-09-30 23:27:37 -0700140 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 unsigned char val;
142
143 if (!capable(CAP_SYS_TIME))
144 return -EACCES;
145
146 spin_lock_irqsave(&ds1286_lock, flags);
147 val = rtc_read(RTC_CMD);
148 val |= RTC_WAM;
149 rtc_write(val, RTC_CMD);
150 spin_unlock_irqrestore(&ds1286_lock, flags);
151
152 return 0;
153 }
154 case RTC_WIE_ON: /* Allow watchdog interrupts. */
155 {
Alexey Dobriyanc53421b2006-09-30 23:27:37 -0700156 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 unsigned char val;
158
159 if (!capable(CAP_SYS_TIME))
160 return -EACCES;
161
162 spin_lock_irqsave(&ds1286_lock, flags);
163 val = rtc_read(RTC_CMD);
164 val &= ~RTC_WAM;
165 rtc_write(val, RTC_CMD);
166 spin_unlock_irqrestore(&ds1286_lock, flags);
167
168 return 0;
169 }
170 case RTC_ALM_READ: /* Read the present alarm time */
171 {
172 /*
173 * This returns a struct rtc_time. Reading >= 0xc0
174 * means "don't care" or "match all". Only the tm_hour,
175 * tm_min, and tm_sec values are filled in.
176 */
177
178 memset(&wtime, 0, sizeof(wtime));
179 ds1286_get_alm_time(&wtime);
180 break;
181 }
182 case RTC_ALM_SET: /* Store a time into the alarm */
183 {
184 /*
185 * This expects a struct rtc_time. Writing 0xff means
186 * "don't care" or "match all". Only the tm_hour,
187 * tm_min and tm_sec are used.
188 */
189 unsigned char hrs, min, sec;
190 struct rtc_time alm_tm;
191
192 if (!capable(CAP_SYS_TIME))
193 return -EACCES;
194
195 if (copy_from_user(&alm_tm, (struct rtc_time*)arg,
196 sizeof(struct rtc_time)))
197 return -EFAULT;
198
199 hrs = alm_tm.tm_hour;
200 min = alm_tm.tm_min;
Ralf Baechleb35692e2007-03-08 00:14:25 +0000201 sec = alm_tm.tm_sec;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202
203 if (hrs >= 24)
204 hrs = 0xff;
205
206 if (min >= 60)
207 min = 0xff;
208
Ralf Baechleb35692e2007-03-08 00:14:25 +0000209 if (sec != 0)
210 return -EINVAL;
211
212 min = BIN2BCD(min);
213 min = BIN2BCD(hrs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214
215 spin_lock(&ds1286_lock);
216 rtc_write(hrs, RTC_HOURS_ALARM);
217 rtc_write(min, RTC_MINUTES_ALARM);
218 spin_unlock(&ds1286_lock);
219
220 return 0;
221 }
222 case RTC_RD_TIME: /* Read the time/date from RTC */
223 {
224 memset(&wtime, 0, sizeof(wtime));
225 ds1286_get_time(&wtime);
226 break;
227 }
228 case RTC_SET_TIME: /* Set the RTC */
229 {
230 struct rtc_time rtc_tm;
231
232 if (!capable(CAP_SYS_TIME))
233 return -EACCES;
234
235 if (copy_from_user(&rtc_tm, (struct rtc_time*)arg,
236 sizeof(struct rtc_time)))
237 return -EFAULT;
238
239 return ds1286_set_time(&rtc_tm);
240 }
241 default:
242 return -EINVAL;
243 }
244 return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
245}
246
247/*
248 * We enforce only one user at a time here with the open/close.
249 * Also clear the previous interrupt data on an open, and clean
250 * up things on a close.
251 */
252
253static int ds1286_open(struct inode *inode, struct file *file)
254{
255 spin_lock_irq(&ds1286_lock);
256
257 if (ds1286_status & RTC_IS_OPEN)
258 goto out_busy;
259
260 ds1286_status |= RTC_IS_OPEN;
261
262 spin_unlock_irq(&ds1286_lock);
263 return 0;
264
265out_busy:
266 spin_lock_irq(&ds1286_lock);
267 return -EBUSY;
268}
269
270static int ds1286_release(struct inode *inode, struct file *file)
271{
272 ds1286_status &= ~RTC_IS_OPEN;
273
274 return 0;
275}
276
277static unsigned int ds1286_poll(struct file *file, poll_table *wait)
278{
279 poll_wait(file, &ds1286_wait, wait);
280
281 return 0;
282}
283
284/*
285 * The various file operations we support.
286 */
287
Arjan van de Ven62322d22006-07-03 00:24:21 -0700288static const struct file_operations ds1286_fops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 .llseek = no_llseek,
290 .read = ds1286_read,
291 .poll = ds1286_poll,
292 .ioctl = ds1286_ioctl,
293 .open = ds1286_open,
294 .release = ds1286_release,
295};
296
297static struct miscdevice ds1286_dev=
298{
299 .minor = RTC_MINOR,
300 .name = "rtc",
301 .fops = &ds1286_fops,
302};
303
304static int __init ds1286_init(void)
305{
306 int err;
307
308 printk(KERN_INFO "DS1286 Real Time Clock Driver v%s\n", DS1286_VERSION);
309
310 err = misc_register(&ds1286_dev);
311 if (err)
312 goto out;
313
314 if (!create_proc_read_entry("driver/rtc", 0, 0, ds1286_read_proc, NULL)) {
315 err = -ENOMEM;
316
317 goto out_deregister;
318 }
319
320 return 0;
321
322out_deregister:
323 misc_deregister(&ds1286_dev);
324
325out:
326 return err;
327}
328
329static void __exit ds1286_exit(void)
330{
331 remove_proc_entry("driver/rtc", NULL);
332 misc_deregister(&ds1286_dev);
333}
334
335static char *days[] = {
336 "***", "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
337};
338
339/*
340 * Info exported via "/proc/rtc".
341 */
342static int ds1286_proc_output(char *buf)
343{
344 char *p, *s;
345 struct rtc_time tm;
346 unsigned char hundredth, month, cmd, amode;
347
348 p = buf;
349
350 ds1286_get_time(&tm);
351 hundredth = rtc_read(RTC_HUNDREDTH_SECOND);
352 BCD_TO_BIN(hundredth);
353
354 p += sprintf(p,
355 "rtc_time\t: %02d:%02d:%02d.%02d\n"
356 "rtc_date\t: %04d-%02d-%02d\n",
357 tm.tm_hour, tm.tm_min, tm.tm_sec, hundredth,
358 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
359
360 /*
361 * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
362 * match any value for that particular field. Values that are
363 * greater than a valid time, but less than 0xc0 shouldn't appear.
364 */
365 ds1286_get_alm_time(&tm);
366 p += sprintf(p, "alarm\t\t: %s ", days[tm.tm_wday]);
367 if (tm.tm_hour <= 24)
368 p += sprintf(p, "%02d:", tm.tm_hour);
369 else
370 p += sprintf(p, "**:");
371
372 if (tm.tm_min <= 59)
373 p += sprintf(p, "%02d\n", tm.tm_min);
374 else
375 p += sprintf(p, "**\n");
376
377 month = rtc_read(RTC_MONTH);
378 p += sprintf(p,
379 "oscillator\t: %s\n"
380 "square_wave\t: %s\n",
381 (month & RTC_EOSC) ? "disabled" : "enabled",
382 (month & RTC_ESQW) ? "disabled" : "enabled");
383
384 amode = ((rtc_read(RTC_MINUTES_ALARM) & 0x80) >> 5) |
385 ((rtc_read(RTC_HOURS_ALARM) & 0x80) >> 6) |
386 ((rtc_read(RTC_DAY_ALARM) & 0x80) >> 7);
387 if (amode == 7) s = "each minute";
388 else if (amode == 3) s = "minutes match";
389 else if (amode == 1) s = "hours and minutes match";
390 else if (amode == 0) s = "days, hours and minutes match";
391 else s = "invalid";
392 p += sprintf(p, "alarm_mode\t: %s\n", s);
393
394 cmd = rtc_read(RTC_CMD);
395 p += sprintf(p,
396 "alarm_enable\t: %s\n"
397 "wdog_alarm\t: %s\n"
398 "alarm_mask\t: %s\n"
399 "wdog_alarm_mask\t: %s\n"
400 "interrupt_mode\t: %s\n"
401 "INTB_mode\t: %s_active\n"
402 "interrupt_pins\t: %s\n",
403 (cmd & RTC_TDF) ? "yes" : "no",
404 (cmd & RTC_WAF) ? "yes" : "no",
405 (cmd & RTC_TDM) ? "disabled" : "enabled",
406 (cmd & RTC_WAM) ? "disabled" : "enabled",
407 (cmd & RTC_PU_LVL) ? "pulse" : "level",
408 (cmd & RTC_IBH_LO) ? "low" : "high",
409 (cmd & RTC_IPSW) ? "unswapped" : "swapped");
410
411 return p - buf;
412}
413
414static int ds1286_read_proc(char *page, char **start, off_t off,
415 int count, int *eof, void *data)
416{
417 int len = ds1286_proc_output (page);
418 if (len <= off+count) *eof = 1;
419 *start = page + off;
420 len -= off;
421 if (len>count)
422 len = count;
423 if (len<0)
424 len = 0;
425
426 return len;
427}
428
429/*
430 * Returns true if a clock update is in progress
431 */
432static inline unsigned char ds1286_is_updating(void)
433{
434 return rtc_read(RTC_CMD) & RTC_TE;
435}
436
437
438static void ds1286_get_time(struct rtc_time *rtc_tm)
439{
440 unsigned char save_control;
Alexey Dobriyanc53421b2006-09-30 23:27:37 -0700441 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 unsigned long uip_watchdog = jiffies;
443
444 /*
445 * read RTC once any update in progress is done. The update
446 * can take just over 2ms. We wait 10 to 20ms. There is no need to
447 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
448 * If you need to know *exactly* when a second has started, enable
449 * periodic update complete interrupts, (via ioctl) and then
450 * immediately read /dev/rtc which will block until you get the IRQ.
451 * Once the read clears, read the RTC time (again via ioctl). Easy.
452 */
453
454 if (ds1286_is_updating() != 0)
Julia Lawallac0e4b72008-04-30 00:53:58 -0700455 while (time_before(jiffies, uip_watchdog + 2*HZ/100))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 barrier();
457
458 /*
459 * Only the values that we read from the RTC are set. We leave
460 * tm_wday, tm_yday and tm_isdst untouched. Even though the
461 * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
462 * by the RTC when initially set to a non-zero value.
463 */
464 spin_lock_irqsave(&ds1286_lock, flags);
465 save_control = rtc_read(RTC_CMD);
466 rtc_write((save_control|RTC_TE), RTC_CMD);
467
468 rtc_tm->tm_sec = rtc_read(RTC_SECONDS);
469 rtc_tm->tm_min = rtc_read(RTC_MINUTES);
470 rtc_tm->tm_hour = rtc_read(RTC_HOURS) & 0x3f;
471 rtc_tm->tm_mday = rtc_read(RTC_DATE);
472 rtc_tm->tm_mon = rtc_read(RTC_MONTH) & 0x1f;
473 rtc_tm->tm_year = rtc_read(RTC_YEAR);
474
475 rtc_write(save_control, RTC_CMD);
476 spin_unlock_irqrestore(&ds1286_lock, flags);
477
478 BCD_TO_BIN(rtc_tm->tm_sec);
479 BCD_TO_BIN(rtc_tm->tm_min);
480 BCD_TO_BIN(rtc_tm->tm_hour);
481 BCD_TO_BIN(rtc_tm->tm_mday);
482 BCD_TO_BIN(rtc_tm->tm_mon);
483 BCD_TO_BIN(rtc_tm->tm_year);
484
485 /*
486 * Account for differences between how the RTC uses the values
487 * and how they are defined in a struct rtc_time;
488 */
489 if (rtc_tm->tm_year < 45)
490 rtc_tm->tm_year += 30;
491 if ((rtc_tm->tm_year += 40) < 70)
492 rtc_tm->tm_year += 100;
493
494 rtc_tm->tm_mon--;
495}
496
497static int ds1286_set_time(struct rtc_time *rtc_tm)
498{
499 unsigned char mon, day, hrs, min, sec, leap_yr;
500 unsigned char save_control;
Alexey Dobriyanc53421b2006-09-30 23:27:37 -0700501 unsigned int yrs;
502 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503
504
505 yrs = rtc_tm->tm_year + 1900;
506 mon = rtc_tm->tm_mon + 1; /* tm_mon starts at zero */
507 day = rtc_tm->tm_mday;
508 hrs = rtc_tm->tm_hour;
509 min = rtc_tm->tm_min;
510 sec = rtc_tm->tm_sec;
511
512 if (yrs < 1970)
513 return -EINVAL;
514
515 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
516
517 if ((mon > 12) || (day == 0))
518 return -EINVAL;
519
520 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
521 return -EINVAL;
522
523 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
524 return -EINVAL;
525
526 if ((yrs -= 1940) > 255) /* They are unsigned */
527 return -EINVAL;
528
529 if (yrs >= 100)
530 yrs -= 100;
531
532 BIN_TO_BCD(sec);
533 BIN_TO_BCD(min);
534 BIN_TO_BCD(hrs);
535 BIN_TO_BCD(day);
536 BIN_TO_BCD(mon);
537 BIN_TO_BCD(yrs);
538
539 spin_lock_irqsave(&ds1286_lock, flags);
540 save_control = rtc_read(RTC_CMD);
541 rtc_write((save_control|RTC_TE), RTC_CMD);
542
543 rtc_write(yrs, RTC_YEAR);
544 rtc_write(mon, RTC_MONTH);
545 rtc_write(day, RTC_DATE);
546 rtc_write(hrs, RTC_HOURS);
547 rtc_write(min, RTC_MINUTES);
548 rtc_write(sec, RTC_SECONDS);
549 rtc_write(0, RTC_HUNDREDTH_SECOND);
550
551 rtc_write(save_control, RTC_CMD);
552 spin_unlock_irqrestore(&ds1286_lock, flags);
553
554 return 0;
555}
556
557static void ds1286_get_alm_time(struct rtc_time *alm_tm)
558{
559 unsigned char cmd;
Alexey Dobriyanc53421b2006-09-30 23:27:37 -0700560 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561
562 /*
563 * Only the values that we read from the RTC are set. That
564 * means only tm_wday, tm_hour, tm_min.
565 */
566 spin_lock_irqsave(&ds1286_lock, flags);
567 alm_tm->tm_min = rtc_read(RTC_MINUTES_ALARM) & 0x7f;
568 alm_tm->tm_hour = rtc_read(RTC_HOURS_ALARM) & 0x1f;
569 alm_tm->tm_wday = rtc_read(RTC_DAY_ALARM) & 0x07;
570 cmd = rtc_read(RTC_CMD);
571 spin_unlock_irqrestore(&ds1286_lock, flags);
572
573 BCD_TO_BIN(alm_tm->tm_min);
574 BCD_TO_BIN(alm_tm->tm_hour);
575 alm_tm->tm_sec = 0;
576}
577
578module_init(ds1286_init);
579module_exit(ds1286_exit);
580
581MODULE_AUTHOR("Ralf Baechle");
582MODULE_LICENSE("GPL");
583MODULE_ALIAS_MISCDEV(RTC_MINOR);