1 /*
2 * An rtc driver for the Dallas DS1511
3 *
4 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
5 * Copyright (C) 2007 Andrew Sharp <andy.sharp@onstor.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * Real time clock driver for the Dallas 1511 chip, which also
12 * contains a watchdog timer. There is a tiny amount of code that
13 * platform code could use to mess with the watchdog device a little
14 * bit, but not a full watchdog driver.
15 */
16
17 #include <linux/bcd.h>
18 #include <linux/init.h>
19 #include <linux/kernel.h>
20 #include <linux/delay.h>
21 #include <linux/interrupt.h>
22 #include <linux/rtc.h>
23 #include <linux/platform_device.h>
24 #include <linux/io.h>
25
26 #define DRV_VERSION "0.6"
27
28 enum ds1511reg {
29 DS1511_SEC = 0x0,
30 DS1511_MIN = 0x1,
31 DS1511_HOUR = 0x2,
32 DS1511_DOW = 0x3,
33 DS1511_DOM = 0x4,
34 DS1511_MONTH = 0x5,
35 DS1511_YEAR = 0x6,
36 DS1511_CENTURY = 0x7,
37 DS1511_AM1_SEC = 0x8,
38 DS1511_AM2_MIN = 0x9,
39 DS1511_AM3_HOUR = 0xa,
40 DS1511_AM4_DATE = 0xb,
41 DS1511_WD_MSEC = 0xc,
42 DS1511_WD_SEC = 0xd,
43 DS1511_CONTROL_A = 0xe,
44 DS1511_CONTROL_B = 0xf,
45 DS1511_RAMADDR_LSB = 0x10,
46 DS1511_RAMDATA = 0x13
47 };
48
49 #define DS1511_BLF1 0x80
50 #define DS1511_BLF2 0x40
51 #define DS1511_PRS 0x20
52 #define DS1511_PAB 0x10
53 #define DS1511_TDF 0x08
54 #define DS1511_KSF 0x04
55 #define DS1511_WDF 0x02
56 #define DS1511_IRQF 0x01
57 #define DS1511_TE 0x80
58 #define DS1511_CS 0x40
59 #define DS1511_BME 0x20
60 #define DS1511_TPE 0x10
61 #define DS1511_TIE 0x08
62 #define DS1511_KIE 0x04
63 #define DS1511_WDE 0x02
64 #define DS1511_WDS 0x01
65 #define DS1511_RAM_MAX 0xff
66
67 #define RTC_CMD DS1511_CONTROL_B
68 #define RTC_CMD1 DS1511_CONTROL_A
69
70 #define RTC_ALARM_SEC DS1511_AM1_SEC
71 #define RTC_ALARM_MIN DS1511_AM2_MIN
72 #define RTC_ALARM_HOUR DS1511_AM3_HOUR
73 #define RTC_ALARM_DATE DS1511_AM4_DATE
74
75 #define RTC_SEC DS1511_SEC
76 #define RTC_MIN DS1511_MIN
77 #define RTC_HOUR DS1511_HOUR
78 #define RTC_DOW DS1511_DOW
79 #define RTC_DOM DS1511_DOM
80 #define RTC_MON DS1511_MONTH
81 #define RTC_YEAR DS1511_YEAR
82 #define RTC_CENTURY DS1511_CENTURY
83
84 #define RTC_TIE DS1511_TIE
85 #define RTC_TE DS1511_TE
86
87 struct rtc_plat_data {
88 struct rtc_device *rtc;
89 void __iomem *ioaddr; /* virtual base address */
90 unsigned long baseaddr; /* physical base address */
91 int size; /* amount of memory mapped */
92 int irq;
93 unsigned int irqen;
94 int alrm_sec;
95 int alrm_min;
96 int alrm_hour;
97 int alrm_mday;
98 };
99
100 static DEFINE_SPINLOCK(ds1511_lock);
101
102 static __iomem char *ds1511_base;
103 static u32 reg_spacing = 1;
104
105 static noinline void
106 rtc_write(uint8_t val, uint32_t reg)
107 {
108 writeb(val, ds1511_base + (reg * reg_spacing));
109 }
110
111 static inline void
112 rtc_write_alarm(uint8_t val, enum ds1511reg reg)
113 {
114 rtc_write((val | 0x80), reg);
115 }
116
117 static noinline uint8_t
118 rtc_read(enum ds1511reg reg)
119 {
120 return readb(ds1511_base + (reg * reg_spacing));
121 }
122
123 static inline void
124 rtc_disable_update(void)
125 {
126 rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD);
127 }
128
129 static void
130 rtc_enable_update(void)
131 {
132 rtc_write((rtc_read(RTC_CMD) | RTC_TE), RTC_CMD);
133 }
134
135 /*
136 * #define DS1511_WDOG_RESET_SUPPORT
137 *
138 * Uncomment this if you want to use these routines in
139 * some platform code.
140 */
141 #ifdef DS1511_WDOG_RESET_SUPPORT
142 /*
143 * just enough code to set the watchdog timer so that it
144 * will reboot the system
145 */
146 void
147 ds1511_wdog_set(unsigned long deciseconds)
148 {
149 /*
150 * the wdog timer can take 99.99 seconds
151 */
152 deciseconds %= 10000;
153 /*
154 * set the wdog values in the wdog registers
155 */
156 rtc_write(BIN2BCD(deciseconds % 100), DS1511_WD_MSEC);
157 rtc_write(BIN2BCD(deciseconds / 100), DS1511_WD_SEC);
158 /*
159 * set wdog enable and wdog 'steering' bit to issue a reset
160 */
161 rtc_write(DS1511_WDE | DS1511_WDS, RTC_CMD);
162 }
163
164 void
165 ds1511_wdog_disable(void)
166 {
167 /*
168 * clear wdog enable and wdog 'steering' bits
169 */
170 rtc_write(rtc_read(RTC_CMD) & ~(DS1511_WDE | DS1511_WDS), RTC_CMD);
171 /*
172 * clear the wdog counter
173 */
174 rtc_write(0, DS1511_WD_MSEC);
175 rtc_write(0, DS1511_WD_SEC);
176 }
177 #endif
178
179 /*
180 * set the rtc chip's idea of the time.
181 * stupidly, some callers call with year unmolested;
182 * and some call with year = year - 1900. thanks.
183 */
184 int
185 ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
186 {
187 u8 mon, day, dow, hrs, min, sec, yrs, cen;
188 unsigned long flags;
189
190 /*
191 * won't have to change this for a while
192 */
193 if (rtc_tm->tm_year < 1900) {
194 rtc_tm->tm_year += 1900;
195 }
196
197 if (rtc_tm->tm_year < 1970) {
198 return -EINVAL;
199 }
200 yrs = rtc_tm->tm_year % 100;
201 cen = rtc_tm->tm_year / 100;
202 mon = rtc_tm->tm_mon + 1; /* tm_mon starts at zero */
203 day = rtc_tm->tm_mday;
204 dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */
205 hrs = rtc_tm->tm_hour;
206 min = rtc_tm->tm_min;
207 sec = rtc_tm->tm_sec;
208
209 if ((mon > 12) || (day == 0)) {
210 return -EINVAL;
211 }
212
213 if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year)) {
214 return -EINVAL;
215 }
216
217 if ((hrs >= 24) || (min >= 60) || (sec >= 60)) {
218 return -EINVAL;
219 }
220
221 /*
222 * each register is a different number of valid bits
223 */
224 sec = BIN2BCD(sec) & 0x7f;
225 min = BIN2BCD(min) & 0x7f;
226 hrs = BIN2BCD(hrs) & 0x3f;
227 day = BIN2BCD(day) & 0x3f;
228 mon = BIN2BCD(mon) & 0x1f;
229 yrs = BIN2BCD(yrs) & 0xff;
230 cen = BIN2BCD(cen) & 0xff;
231
232 spin_lock_irqsave(&ds1511_lock, flags);
233 rtc_disable_update();
234 rtc_write(cen, RTC_CENTURY);
235 rtc_write(yrs, RTC_YEAR);
236 rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON);
237 rtc_write(day, RTC_DOM);
238 rtc_write(hrs, RTC_HOUR);
239 rtc_write(min, RTC_MIN);
240 rtc_write(sec, RTC_SEC);
241 rtc_write(dow, RTC_DOW);
242 rtc_enable_update();
243 spin_unlock_irqrestore(&ds1511_lock, flags);
244
245 return 0;
246 }
247
248 int
249 ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
250 {
251 unsigned int century;
252 unsigned long flags;
253
254 spin_lock_irqsave(&ds1511_lock, flags);
255 rtc_disable_update();
256
257 rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f;
258 rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f;
259 rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f;
260 rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f;
261 rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7;
262 rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f;
263 rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f;
264 century = rtc_read(RTC_CENTURY);
265
266 rtc_enable_update();
267 spin_unlock_irqrestore(&ds1511_lock, flags);
268
269 rtc_tm->tm_sec = BCD2BIN(rtc_tm->tm_sec);
270 rtc_tm->tm_min = BCD2BIN(rtc_tm->tm_min);
271 rtc_tm->tm_hour = BCD2BIN(rtc_tm->tm_hour);
272 rtc_tm->tm_mday = BCD2BIN(rtc_tm->tm_mday);
273 rtc_tm->tm_wday = BCD2BIN(rtc_tm->tm_wday);
274 rtc_tm->tm_mon = BCD2BIN(rtc_tm->tm_mon);
275 rtc_tm->tm_year = BCD2BIN(rtc_tm->tm_year);
276 century = BCD2BIN(century) * 100;
277
278 /*
279 * Account for differences between how the RTC uses the values
280 * and how they are defined in a struct rtc_time;
281 */
282 century += rtc_tm->tm_year;
283 rtc_tm->tm_year = century - 1900;
284
285 rtc_tm->tm_mon--;
286
287 if (rtc_valid_tm(rtc_tm) < 0) {
288 dev_err(dev, "retrieved date/time is not valid.\n");
289 rtc_time_to_tm(0, rtc_tm);
290 }
291 return 0;
292 }
293
294 /*
295 * write the alarm register settings
296 *
297 * we only have the use to interrupt every second, otherwise
298 * known as the update interrupt, or the interrupt if the whole
299 * date/hours/mins/secs matches. the ds1511 has many more
300 * permutations, but the kernel doesn't.
301 */
302 static void
303 ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
304 {
305 unsigned long flags;
306
307 spin_lock_irqsave(&pdata->rtc->irq_lock, flags);
308 rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
309 0x80 : BIN2BCD(pdata->alrm_mday) & 0x3f,
310 RTC_ALARM_DATE);
311 rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
312 0x80 : BIN2BCD(pdata->alrm_hour) & 0x3f,
313 RTC_ALARM_HOUR);
314 rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
315 0x80 : BIN2BCD(pdata->alrm_min) & 0x7f,
316 RTC_ALARM_MIN);
317 rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
318 0x80 : BIN2BCD(pdata->alrm_sec) & 0x7f,
319 RTC_ALARM_SEC);
320 rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD);
321 rtc_read(RTC_CMD1); /* clear interrupts */
322 spin_unlock_irqrestore(&pdata->rtc->irq_lock, flags);
323 }
324
325 static int
326 ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
327 {
328 struct platform_device *pdev = to_platform_device(dev);
329 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
330
331 if (pdata->irq < 0) {
332 return -EINVAL;
333 }
334 pdata->alrm_mday = alrm->time.tm_mday;
335 pdata->alrm_hour = alrm->time.tm_hour;
336 pdata->alrm_min = alrm->time.tm_min;
337 pdata->alrm_sec = alrm->time.tm_sec;
338 if (alrm->enabled) {
339 pdata->irqen |= RTC_AF;
340 }
341 ds1511_rtc_update_alarm(pdata);
342 return 0;
343 }
344
345 static int
346 ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
347 {
348 struct platform_device *pdev = to_platform_device(dev);
349 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
350
351 if (pdata->irq < 0) {
352 return -EINVAL;
353 }
354 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
355 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
356 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
357 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
358 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
359 return 0;
360 }
361
362 static irqreturn_t
363 ds1511_interrupt(int irq, void *dev_id)
364 {
365 struct platform_device *pdev = dev_id;
366 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
367 unsigned long events = RTC_IRQF;
368
369 /*
370 * read and clear interrupt
371 */
372 if (!(rtc_read(RTC_CMD1) & DS1511_IRQF)) {
373 return IRQ_NONE;
374 }
375 if (rtc_read(RTC_ALARM_SEC) & 0x80) {
376 events |= RTC_UF;
377 } else {
378 events |= RTC_AF;
379 }
380 rtc_update_irq(pdata->rtc, 1, events);
381 return IRQ_HANDLED;
382 }
383
384 static void
385 ds1511_rtc_release(struct device *dev)
386 {
387 struct platform_device *pdev = to_platform_device(dev);
388 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
389
390 if (pdata->irq >= 0) {
391 pdata->irqen = 0;
392 ds1511_rtc_update_alarm(pdata);
393 }
394 }
395
396 static int
397 ds1511_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
398 {
399 struct platform_device *pdev = to_platform_device(dev);
400 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
401
402 if (pdata->irq < 0) {
403 return -ENOIOCTLCMD; /* fall back into rtc-dev's emulation */
404 }
405 switch (cmd) {
406 case RTC_AIE_OFF:
407 pdata->irqen &= ~RTC_AF;
408 ds1511_rtc_update_alarm(pdata);
409 break;
410 case RTC_AIE_ON:
411 pdata->irqen |= RTC_AF;
412 ds1511_rtc_update_alarm(pdata);
413 break;
414 case RTC_UIE_OFF:
415 pdata->irqen &= ~RTC_UF;
416 ds1511_rtc_update_alarm(pdata);
417 break;
418 case RTC_UIE_ON:
419 pdata->irqen |= RTC_UF;
420 ds1511_rtc_update_alarm(pdata);
421 break;
422 default:
423 return -ENOIOCTLCMD;
424 }
425 return 0;
426 }
427
428 static const struct rtc_class_ops ds1511_rtc_ops = {
429 .read_time = ds1511_rtc_read_time,
430 .set_time = ds1511_rtc_set_time,
431 .read_alarm = ds1511_rtc_read_alarm,
432 .set_alarm = ds1511_rtc_set_alarm,
433 .release = ds1511_rtc_release,
434 .ioctl = ds1511_rtc_ioctl,
435 };
436
437 static ssize_t
438 ds1511_nvram_read(struct kobject *kobj, struct bin_attribute *ba,
439 char *buf, loff_t pos, size_t size)
440 {
441 ssize_t count;
442
443 /*
444 * if count is more than one, turn on "burst" mode
445 * turn it off when you're done
446 */
447 if (size > 1) {
448 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
449 }
450 if (pos > DS1511_RAM_MAX) {
451 pos = DS1511_RAM_MAX;
452 }
453 if (size + pos > DS1511_RAM_MAX + 1) {
454 size = DS1511_RAM_MAX - pos + 1;
455 }
456 rtc_write(pos, DS1511_RAMADDR_LSB);
457 for (count = 0; size > 0; count++, size--) {
458 *buf++ = rtc_read(DS1511_RAMDATA);
459 }
460 if (count > 1) {
461 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
462 }
463 return count;
464 }
465
466 static ssize_t
467 ds1511_nvram_write(struct kobject *kobj, struct bin_attribute *bin_attr,
468 char *buf, loff_t pos, size_t size)
469 {
470 ssize_t count;
471
472 /*
473 * if count is more than one, turn on "burst" mode
474 * turn it off when you're done
475 */
476 if (size > 1) {
477 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
478 }
479 if (pos > DS1511_RAM_MAX) {
480 pos = DS1511_RAM_MAX;
481 }
482 if (size + pos > DS1511_RAM_MAX + 1) {
483 size = DS1511_RAM_MAX - pos + 1;
484 }
485 rtc_write(pos, DS1511_RAMADDR_LSB);
486 for (count = 0; size > 0; count++, size--) {
487 rtc_write(*buf++, DS1511_RAMDATA);
488 }
489 if (count > 1) {
490 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
491 }
492 return count;
493 }
494
495 static struct bin_attribute ds1511_nvram_attr = {
496 .attr = {
497 .name = "nvram",
498 .mode = S_IRUGO | S_IWUGO,
499 .owner = THIS_MODULE,
500 },
501 .size = DS1511_RAM_MAX,
502 .read = ds1511_nvram_read,
503 .write = ds1511_nvram_write,
504 };
505
506 static int __devinit
507 ds1511_rtc_probe(struct platform_device *pdev)
508 {
509 struct rtc_device *rtc;
510 struct resource *res;
511 struct rtc_plat_data *pdata = NULL;
512 int ret = 0;
513
514 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
515 if (!res) {
516 return -ENODEV;
517 }
518 pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
519 if (!pdata) {
520 return -ENOMEM;
521 }
522 pdata->irq = -1;
523 pdata->size = res->end - res->start + 1;
524 if (!request_mem_region(res->start, pdata->size, pdev->name)) {
525 ret = -EBUSY;
526 goto out;
527 }
528 pdata->baseaddr = res->start;
529 pdata->size = pdata->size;
530 ds1511_base = ioremap(pdata->baseaddr, pdata->size);
531 if (!ds1511_base) {
532 ret = -ENOMEM;
533 goto out;
534 }
535 pdata->ioaddr = ds1511_base;
536 pdata->irq = platform_get_irq(pdev, 0);
537
538 /*
539 * turn on the clock and the crystal, etc.
540 */
541 rtc_write(0, RTC_CMD);
542 rtc_write(0, RTC_CMD1);
543 /*
544 * clear the wdog counter
545 */
546 rtc_write(0, DS1511_WD_MSEC);
547 rtc_write(0, DS1511_WD_SEC);
548 /*
549 * start the clock
550 */
551 rtc_enable_update();
552
553 /*
554 * check for a dying bat-tree
555 */
556 if (rtc_read(RTC_CMD1) & DS1511_BLF1) {
557 dev_warn(&pdev->dev, "voltage-low detected.\n");
558 }
559
560 /*
561 * if the platform has an interrupt in mind for this device,
562 * then by all means, set it
563 */
564 if (pdata->irq >= 0) {
565 rtc_read(RTC_CMD1);
566 if (request_irq(pdata->irq, ds1511_interrupt,
567 IRQF_DISABLED | IRQF_SHARED, pdev->name, pdev) < 0) {
568
569 dev_warn(&pdev->dev, "interrupt not available.\n");
570 pdata->irq = -1;
571 }
572 }
573
574 rtc = rtc_device_register(pdev->name, &pdev->dev, &ds1511_rtc_ops,
575 THIS_MODULE);
576 if (IS_ERR(rtc)) {
577 ret = PTR_ERR(rtc);
578 goto out;
579 }
580 pdata->rtc = rtc;
581 platform_set_drvdata(pdev, pdata);
582 ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
583 if (ret) {
584 goto out;
585 }
586 return 0;
587 out:
588 if (pdata->rtc) {
589 rtc_device_unregister(pdata->rtc);
590 }
591 if (pdata->irq >= 0) {
592 free_irq(pdata->irq, pdev);
593 }
594 if (ds1511_base) {
595 iounmap(ds1511_base);
596 ds1511_base = NULL;
597 }
598 if (pdata->baseaddr) {
599 release_mem_region(pdata->baseaddr, pdata->size);
600 }
601
602 kfree(pdata);
603 return ret;
604 }
605
606 static int __devexit
607 ds1511_rtc_remove(struct platform_device *pdev)
608 {
609 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
610
611 sysfs_remove_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
612 rtc_device_unregister(pdata->rtc);
613 pdata->rtc = NULL;
614 if (pdata->irq >= 0) {
615 /*
616 * disable the alarm interrupt
617 */
618 rtc_write(rtc_read(RTC_CMD) & ~RTC_TIE, RTC_CMD);
619 rtc_read(RTC_CMD1);
620 free_irq(pdata->irq, pdev);
621 }
622 iounmap(pdata->ioaddr);
623 ds1511_base = NULL;
624 release_mem_region(pdata->baseaddr, pdata->size);
625 kfree(pdata);
626 return 0;
627 }
628
629 /* work with hotplug and coldplug */
630 MODULE_ALIAS("platform:ds1511");
631
632 static struct platform_driver ds1511_rtc_driver = {
633 .probe = ds1511_rtc_probe,
634 .remove = __devexit_p(ds1511_rtc_remove),
635 .driver = {
636 .name = "ds1511",
637 .owner = THIS_MODULE,
638 },
639 };
640
641 static int __init
642 ds1511_rtc_init(void)
643 {
644 return platform_driver_register(&ds1511_rtc_driver);
645 }
646
647 static void __exit
648 ds1511_rtc_exit(void)
649 {
650 return platform_driver_unregister(&ds1511_rtc_driver);
651 }
652
653 module_init(ds1511_rtc_init);
654 module_exit(ds1511_rtc_exit);
655
656 MODULE_AUTHOR("Andrew Sharp <andy.sharp@onstor.com>");
657 MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
658 MODULE_LICENSE("GPL");
659 MODULE_VERSION(DRV_VERSION);
660
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