xref: /openbmc/linux/drivers/rtc/rtc-ds1511.c (revision b6dcefde)
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@lsi.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 	int size;				/* amount of memory mapped */
91 	int irq;
92 	unsigned int irqen;
93 	int alrm_sec;
94 	int alrm_min;
95 	int alrm_hour;
96 	int alrm_mday;
97 	spinlock_t lock;
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 static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
185 {
186 	u8 mon, day, dow, hrs, min, sec, yrs, cen;
187 	unsigned long flags;
188 
189 	/*
190 	 * won't have to change this for a while
191 	 */
192 	if (rtc_tm->tm_year < 1900) {
193 		rtc_tm->tm_year += 1900;
194 	}
195 
196 	if (rtc_tm->tm_year < 1970) {
197 		return -EINVAL;
198 	}
199 	yrs = rtc_tm->tm_year % 100;
200 	cen = rtc_tm->tm_year / 100;
201 	mon = rtc_tm->tm_mon + 1;   /* tm_mon starts at zero */
202 	day = rtc_tm->tm_mday;
203 	dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */
204 	hrs = rtc_tm->tm_hour;
205 	min = rtc_tm->tm_min;
206 	sec = rtc_tm->tm_sec;
207 
208 	if ((mon > 12) || (day == 0)) {
209 		return -EINVAL;
210 	}
211 
212 	if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year)) {
213 		return -EINVAL;
214 	}
215 
216 	if ((hrs >= 24) || (min >= 60) || (sec >= 60)) {
217 		return -EINVAL;
218 	}
219 
220 	/*
221 	 * each register is a different number of valid bits
222 	 */
223 	sec = bin2bcd(sec) & 0x7f;
224 	min = bin2bcd(min) & 0x7f;
225 	hrs = bin2bcd(hrs) & 0x3f;
226 	day = bin2bcd(day) & 0x3f;
227 	mon = bin2bcd(mon) & 0x1f;
228 	yrs = bin2bcd(yrs) & 0xff;
229 	cen = bin2bcd(cen) & 0xff;
230 
231 	spin_lock_irqsave(&ds1511_lock, flags);
232 	rtc_disable_update();
233 	rtc_write(cen, RTC_CENTURY);
234 	rtc_write(yrs, RTC_YEAR);
235 	rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON);
236 	rtc_write(day, RTC_DOM);
237 	rtc_write(hrs, RTC_HOUR);
238 	rtc_write(min, RTC_MIN);
239 	rtc_write(sec, RTC_SEC);
240 	rtc_write(dow, RTC_DOW);
241 	rtc_enable_update();
242 	spin_unlock_irqrestore(&ds1511_lock, flags);
243 
244 	return 0;
245 }
246 
247 static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
248 {
249 	unsigned int century;
250 	unsigned long flags;
251 
252 	spin_lock_irqsave(&ds1511_lock, flags);
253 	rtc_disable_update();
254 
255 	rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f;
256 	rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f;
257 	rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f;
258 	rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f;
259 	rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7;
260 	rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f;
261 	rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f;
262 	century = rtc_read(RTC_CENTURY);
263 
264 	rtc_enable_update();
265 	spin_unlock_irqrestore(&ds1511_lock, flags);
266 
267 	rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
268 	rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
269 	rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
270 	rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
271 	rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
272 	rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
273 	rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
274 	century = bcd2bin(century) * 100;
275 
276 	/*
277 	 * Account for differences between how the RTC uses the values
278 	 * and how they are defined in a struct rtc_time;
279 	 */
280 	century += rtc_tm->tm_year;
281 	rtc_tm->tm_year = century - 1900;
282 
283 	rtc_tm->tm_mon--;
284 
285 	if (rtc_valid_tm(rtc_tm) < 0) {
286 		dev_err(dev, "retrieved date/time is not valid.\n");
287 		rtc_time_to_tm(0, rtc_tm);
288 	}
289 	return 0;
290 }
291 
292 /*
293  * write the alarm register settings
294  *
295  * we only have the use to interrupt every second, otherwise
296  * known as the update interrupt, or the interrupt if the whole
297  * date/hours/mins/secs matches.  the ds1511 has many more
298  * permutations, but the kernel doesn't.
299  */
300  static void
301 ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
302 {
303 	unsigned long flags;
304 
305 	spin_lock_irqsave(&pdata->lock, flags);
306 	rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
307 	       0x80 : bin2bcd(pdata->alrm_mday) & 0x3f,
308 	       RTC_ALARM_DATE);
309 	rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
310 	       0x80 : bin2bcd(pdata->alrm_hour) & 0x3f,
311 	       RTC_ALARM_HOUR);
312 	rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
313 	       0x80 : bin2bcd(pdata->alrm_min) & 0x7f,
314 	       RTC_ALARM_MIN);
315 	rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
316 	       0x80 : bin2bcd(pdata->alrm_sec) & 0x7f,
317 	       RTC_ALARM_SEC);
318 	rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD);
319 	rtc_read(RTC_CMD1);	/* clear interrupts */
320 	spin_unlock_irqrestore(&pdata->lock, flags);
321 }
322 
323  static int
324 ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
325 {
326 	struct platform_device *pdev = to_platform_device(dev);
327 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
328 
329 	if (pdata->irq <= 0)
330 		return -EINVAL;
331 
332 	pdata->alrm_mday = alrm->time.tm_mday;
333 	pdata->alrm_hour = alrm->time.tm_hour;
334 	pdata->alrm_min = alrm->time.tm_min;
335 	pdata->alrm_sec = alrm->time.tm_sec;
336 	if (alrm->enabled) {
337 		pdata->irqen |= RTC_AF;
338 	}
339 	ds1511_rtc_update_alarm(pdata);
340 	return 0;
341 }
342 
343  static int
344 ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
345 {
346 	struct platform_device *pdev = to_platform_device(dev);
347 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
348 
349 	if (pdata->irq <= 0)
350 		return -EINVAL;
351 
352 	alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
353 	alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
354 	alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
355 	alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
356 	alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
357 	return 0;
358 }
359 
360  static irqreturn_t
361 ds1511_interrupt(int irq, void *dev_id)
362 {
363 	struct platform_device *pdev = dev_id;
364 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
365 	unsigned long events = 0;
366 
367 	spin_lock(&pdata->lock);
368 	/*
369 	 * read and clear interrupt
370 	 */
371 	if (rtc_read(RTC_CMD1) & DS1511_IRQF) {
372 		events = RTC_IRQF;
373 		if (rtc_read(RTC_ALARM_SEC) & 0x80)
374 			events |= RTC_UF;
375 		else
376 			events |= RTC_AF;
377 		if (likely(pdata->rtc))
378 			rtc_update_irq(pdata->rtc, 1, events);
379 	}
380 	spin_unlock(&pdata->lock);
381 	return events ? IRQ_HANDLED : IRQ_NONE;
382 }
383 
384 static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
385 {
386 	struct platform_device *pdev = to_platform_device(dev);
387 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
388 
389 	if (pdata->irq <= 0)
390 		return -EINVAL;
391 	if (enabled)
392 		pdata->irqen |= RTC_AF;
393 	else
394 		pdata->irqen &= ~RTC_AF;
395 	ds1511_rtc_update_alarm(pdata);
396 	return 0;
397 }
398 
399 static int ds1511_rtc_update_irq_enable(struct device *dev,
400 	unsigned int enabled)
401 {
402 	struct platform_device *pdev = to_platform_device(dev);
403 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
404 
405 	if (pdata->irq <= 0)
406 		return -EINVAL;
407 	if (enabled)
408 		pdata->irqen |= RTC_UF;
409 	else
410 		pdata->irqen &= ~RTC_UF;
411 	ds1511_rtc_update_alarm(pdata);
412 	return 0;
413 }
414 
415 static const struct rtc_class_ops ds1511_rtc_ops = {
416 	.read_time		= ds1511_rtc_read_time,
417 	.set_time		= ds1511_rtc_set_time,
418 	.read_alarm		= ds1511_rtc_read_alarm,
419 	.set_alarm		= ds1511_rtc_set_alarm,
420 	.alarm_irq_enable	= ds1511_rtc_alarm_irq_enable,
421 	.update_irq_enable	= ds1511_rtc_update_irq_enable,
422 };
423 
424  static ssize_t
425 ds1511_nvram_read(struct kobject *kobj, struct bin_attribute *ba,
426 				char *buf, loff_t pos, size_t size)
427 {
428 	ssize_t count;
429 
430 	/*
431 	 * if count is more than one, turn on "burst" mode
432 	 * turn it off when you're done
433 	 */
434 	if (size > 1) {
435 		rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
436 	}
437 	if (pos > DS1511_RAM_MAX) {
438 		pos = DS1511_RAM_MAX;
439 	}
440 	if (size + pos > DS1511_RAM_MAX + 1) {
441 		size = DS1511_RAM_MAX - pos + 1;
442 	}
443 	rtc_write(pos, DS1511_RAMADDR_LSB);
444 	for (count = 0; size > 0; count++, size--) {
445 		*buf++ = rtc_read(DS1511_RAMDATA);
446 	}
447 	if (count > 1) {
448 		rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
449 	}
450 	return count;
451 }
452 
453  static ssize_t
454 ds1511_nvram_write(struct kobject *kobj, struct bin_attribute *bin_attr,
455 				char *buf, loff_t pos, size_t size)
456 {
457 	ssize_t count;
458 
459 	/*
460 	 * if count is more than one, turn on "burst" mode
461 	 * turn it off when you're done
462 	 */
463 	if (size > 1) {
464 		rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
465 	}
466 	if (pos > DS1511_RAM_MAX) {
467 		pos = DS1511_RAM_MAX;
468 	}
469 	if (size + pos > DS1511_RAM_MAX + 1) {
470 		size = DS1511_RAM_MAX - pos + 1;
471 	}
472 	rtc_write(pos, DS1511_RAMADDR_LSB);
473 	for (count = 0; size > 0; count++, size--) {
474 		rtc_write(*buf++, DS1511_RAMDATA);
475 	}
476 	if (count > 1) {
477 		rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
478 	}
479 	return count;
480 }
481 
482 static struct bin_attribute ds1511_nvram_attr = {
483 	.attr = {
484 		.name = "nvram",
485 		.mode = S_IRUGO | S_IWUGO,
486 	},
487 	.size = DS1511_RAM_MAX,
488 	.read = ds1511_nvram_read,
489 	.write = ds1511_nvram_write,
490 };
491 
492  static int __devinit
493 ds1511_rtc_probe(struct platform_device *pdev)
494 {
495 	struct rtc_device *rtc;
496 	struct resource *res;
497 	struct rtc_plat_data *pdata;
498 	int ret = 0;
499 
500 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
501 	if (!res) {
502 		return -ENODEV;
503 	}
504 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
505 	if (!pdata)
506 		return -ENOMEM;
507 	pdata->size = res->end - res->start + 1;
508 	if (!devm_request_mem_region(&pdev->dev, res->start, pdata->size,
509 			pdev->name))
510 		return -EBUSY;
511 	ds1511_base = devm_ioremap(&pdev->dev, res->start, pdata->size);
512 	if (!ds1511_base)
513 		return -ENOMEM;
514 	pdata->ioaddr = ds1511_base;
515 	pdata->irq = platform_get_irq(pdev, 0);
516 
517 	/*
518 	 * turn on the clock and the crystal, etc.
519 	 */
520 	rtc_write(0, RTC_CMD);
521 	rtc_write(0, RTC_CMD1);
522 	/*
523 	 * clear the wdog counter
524 	 */
525 	rtc_write(0, DS1511_WD_MSEC);
526 	rtc_write(0, DS1511_WD_SEC);
527 	/*
528 	 * start the clock
529 	 */
530 	rtc_enable_update();
531 
532 	/*
533 	 * check for a dying bat-tree
534 	 */
535 	if (rtc_read(RTC_CMD1) & DS1511_BLF1) {
536 		dev_warn(&pdev->dev, "voltage-low detected.\n");
537 	}
538 
539 	spin_lock_init(&pdata->lock);
540 	platform_set_drvdata(pdev, pdata);
541 	/*
542 	 * if the platform has an interrupt in mind for this device,
543 	 * then by all means, set it
544 	 */
545 	if (pdata->irq > 0) {
546 		rtc_read(RTC_CMD1);
547 		if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt,
548 			IRQF_DISABLED | IRQF_SHARED, pdev->name, pdev) < 0) {
549 
550 			dev_warn(&pdev->dev, "interrupt not available.\n");
551 			pdata->irq = 0;
552 		}
553 	}
554 
555 	rtc = rtc_device_register(pdev->name, &pdev->dev, &ds1511_rtc_ops,
556 		THIS_MODULE);
557 	if (IS_ERR(rtc))
558 		return PTR_ERR(rtc);
559 	pdata->rtc = rtc;
560 
561 	ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
562 	if (ret)
563 		rtc_device_unregister(pdata->rtc);
564 	return ret;
565 }
566 
567  static int __devexit
568 ds1511_rtc_remove(struct platform_device *pdev)
569 {
570 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
571 
572 	sysfs_remove_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
573 	rtc_device_unregister(pdata->rtc);
574 	if (pdata->irq > 0) {
575 		/*
576 		 * disable the alarm interrupt
577 		 */
578 		rtc_write(rtc_read(RTC_CMD) & ~RTC_TIE, RTC_CMD);
579 		rtc_read(RTC_CMD1);
580 	}
581 	return 0;
582 }
583 
584 /* work with hotplug and coldplug */
585 MODULE_ALIAS("platform:ds1511");
586 
587 static struct platform_driver ds1511_rtc_driver = {
588 	.probe		= ds1511_rtc_probe,
589 	.remove		= __devexit_p(ds1511_rtc_remove),
590 	.driver		= {
591 		.name	= "ds1511",
592 		.owner	= THIS_MODULE,
593 	},
594 };
595 
596  static int __init
597 ds1511_rtc_init(void)
598 {
599 	return platform_driver_register(&ds1511_rtc_driver);
600 }
601 
602  static void __exit
603 ds1511_rtc_exit(void)
604 {
605 	platform_driver_unregister(&ds1511_rtc_driver);
606 }
607 
608 module_init(ds1511_rtc_init);
609 module_exit(ds1511_rtc_exit);
610 
611 MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
612 MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
613 MODULE_LICENSE("GPL");
614 MODULE_VERSION(DRV_VERSION);
615