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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Real Time Clock interface for Linux on Atmel AT91RM9200
4 *
5 * Copyright (C) 2002 Rick Bronson
6 *
7 * Converted to RTC class model by Andrew Victor
8 *
9 * Ported to Linux 2.6 by Steven Scholz
10 * Based on s3c2410-rtc.c Simtec Electronics
11 *
12 * Based on sa1100-rtc.c by Nils Faerber
13 * Based on rtc.c by Paul Gortmaker
14 */
15
16#include <linux/bcd.h>
17#include <linux/bitfield.h>
18#include <linux/clk.h>
19#include <linux/completion.h>
20#include <linux/interrupt.h>
21#include <linux/ioctl.h>
22#include <linux/io.h>
23#include <linux/kernel.h>
24#include <linux/module.h>
25#include <linux/of.h>
26#include <linux/platform_device.h>
27#include <linux/rtc.h>
28#include <linux/spinlock.h>
29#include <linux/suspend.h>
30#include <linux/time.h>
31#include <linux/uaccess.h>
32
33#define AT91_RTC_CR 0x00 /* Control Register */
34#define AT91_RTC_UPDTIM BIT(0) /* Update Request Time Register */
35#define AT91_RTC_UPDCAL BIT(1) /* Update Request Calendar Register */
36
37#define AT91_RTC_MR 0x04 /* Mode Register */
38#define AT91_RTC_HRMOD BIT(0) /* 12/24 hour mode */
39#define AT91_RTC_NEGPPM BIT(4) /* Negative PPM correction */
40#define AT91_RTC_CORRECTION GENMASK(14, 8) /* Slow clock correction */
41#define AT91_RTC_HIGHPPM BIT(15) /* High PPM correction */
42
43#define AT91_RTC_TIMR 0x08 /* Time Register */
44#define AT91_RTC_SEC GENMASK(6, 0) /* Current Second */
45#define AT91_RTC_MIN GENMASK(14, 8) /* Current Minute */
46#define AT91_RTC_HOUR GENMASK(21, 16) /* Current Hour */
47#define AT91_RTC_AMPM BIT(22) /* Ante Meridiem Post Meridiem Indicator */
48
49#define AT91_RTC_CALR 0x0c /* Calendar Register */
50#define AT91_RTC_CENT GENMASK(6, 0) /* Current Century */
51#define AT91_RTC_YEAR GENMASK(15, 8) /* Current Year */
52#define AT91_RTC_MONTH GENMASK(20, 16) /* Current Month */
53#define AT91_RTC_DAY GENMASK(23, 21) /* Current Day */
54#define AT91_RTC_DATE GENMASK(29, 24) /* Current Date */
55
56#define AT91_RTC_TIMALR 0x10 /* Time Alarm Register */
57#define AT91_RTC_SECEN BIT(7) /* Second Alarm Enable */
58#define AT91_RTC_MINEN BIT(15) /* Minute Alarm Enable */
59#define AT91_RTC_HOUREN BIT(23) /* Hour Alarm Enable */
60
61#define AT91_RTC_CALALR 0x14 /* Calendar Alarm Register */
62#define AT91_RTC_MTHEN BIT(23) /* Month Alarm Enable */
63#define AT91_RTC_DATEEN BIT(31) /* Date Alarm Enable */
64
65#define AT91_RTC_SR 0x18 /* Status Register */
66#define AT91_RTC_ACKUPD BIT(0) /* Acknowledge for Update */
67#define AT91_RTC_ALARM BIT(1) /* Alarm Flag */
68#define AT91_RTC_SECEV BIT(2) /* Second Event */
69#define AT91_RTC_TIMEV BIT(3) /* Time Event */
70#define AT91_RTC_CALEV BIT(4) /* Calendar Event */
71
72#define AT91_RTC_SCCR 0x1c /* Status Clear Command Register */
73#define AT91_RTC_IER 0x20 /* Interrupt Enable Register */
74#define AT91_RTC_IDR 0x24 /* Interrupt Disable Register */
75#define AT91_RTC_IMR 0x28 /* Interrupt Mask Register */
76
77#define AT91_RTC_VER 0x2c /* Valid Entry Register */
78#define AT91_RTC_NVTIM BIT(0) /* Non valid Time */
79#define AT91_RTC_NVCAL BIT(1) /* Non valid Calendar */
80#define AT91_RTC_NVTIMALR BIT(2) /* Non valid Time Alarm */
81#define AT91_RTC_NVCALALR BIT(3) /* Non valid Calendar Alarm */
82
83#define AT91_RTC_CORR_DIVIDEND 3906000
84#define AT91_RTC_CORR_LOW_RATIO 20
85
86#define at91_rtc_read(field) \
87 readl_relaxed(at91_rtc_regs + field)
88#define at91_rtc_write(field, val) \
89 writel_relaxed((val), at91_rtc_regs + field)
90
91struct at91_rtc_config {
92 bool use_shadow_imr;
93 bool has_correction;
94};
95
96static const struct at91_rtc_config *at91_rtc_config;
97static DECLARE_COMPLETION(at91_rtc_updated);
98static DECLARE_COMPLETION(at91_rtc_upd_rdy);
99static void __iomem *at91_rtc_regs;
100static int irq;
101static DEFINE_SPINLOCK(at91_rtc_lock);
102static u32 at91_rtc_shadow_imr;
103static bool suspended;
104static DEFINE_SPINLOCK(suspended_lock);
105static unsigned long cached_events;
106static u32 at91_rtc_imr;
107static struct clk *sclk;
108
109static void at91_rtc_write_ier(u32 mask)
110{
111 unsigned long flags;
112
113 spin_lock_irqsave(&at91_rtc_lock, flags);
114 at91_rtc_shadow_imr |= mask;
115 at91_rtc_write(AT91_RTC_IER, mask);
116 spin_unlock_irqrestore(&at91_rtc_lock, flags);
117}
118
119static void at91_rtc_write_idr(u32 mask)
120{
121 unsigned long flags;
122
123 spin_lock_irqsave(&at91_rtc_lock, flags);
124 at91_rtc_write(AT91_RTC_IDR, mask);
125 /*
126 * Register read back (of any RTC-register) needed to make sure
127 * IDR-register write has reached the peripheral before updating
128 * shadow mask.
129 *
130 * Note that there is still a possibility that the mask is updated
131 * before interrupts have actually been disabled in hardware. The only
132 * way to be certain would be to poll the IMR-register, which is
133 * the very register we are trying to emulate. The register read back
134 * is a reasonable heuristic.
135 */
136 at91_rtc_read(AT91_RTC_SR);
137 at91_rtc_shadow_imr &= ~mask;
138 spin_unlock_irqrestore(&at91_rtc_lock, flags);
139}
140
141static u32 at91_rtc_read_imr(void)
142{
143 unsigned long flags;
144 u32 mask;
145
146 if (at91_rtc_config->use_shadow_imr) {
147 spin_lock_irqsave(&at91_rtc_lock, flags);
148 mask = at91_rtc_shadow_imr;
149 spin_unlock_irqrestore(&at91_rtc_lock, flags);
150 } else {
151 mask = at91_rtc_read(AT91_RTC_IMR);
152 }
153
154 return mask;
155}
156
157/*
158 * Decode time/date into rtc_time structure
159 */
160static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
161 struct rtc_time *tm)
162{
163 unsigned int time, date;
164
165 /* must read twice in case it changes */
166 do {
167 time = at91_rtc_read(timereg);
168 date = at91_rtc_read(calreg);
169 } while ((time != at91_rtc_read(timereg)) ||
170 (date != at91_rtc_read(calreg)));
171
172 tm->tm_sec = bcd2bin(FIELD_GET(AT91_RTC_SEC, time));
173 tm->tm_min = bcd2bin(FIELD_GET(AT91_RTC_MIN, time));
174 tm->tm_hour = bcd2bin(FIELD_GET(AT91_RTC_HOUR, time));
175
176 /*
177 * The Calendar Alarm register does not have a field for
178 * the year - so these will return an invalid value.
179 */
180 tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */
181 tm->tm_year += bcd2bin(FIELD_GET(AT91_RTC_YEAR, date)); /* year */
182
183 tm->tm_wday = bcd2bin(FIELD_GET(AT91_RTC_DAY, date)) - 1; /* day of the week [0-6], Sunday=0 */
184 tm->tm_mon = bcd2bin(FIELD_GET(AT91_RTC_MONTH, date)) - 1;
185 tm->tm_mday = bcd2bin(FIELD_GET(AT91_RTC_DATE, date));
186}
187
188/*
189 * Read current time and date in RTC
190 */
191static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
192{
193 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
194 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
195 tm->tm_year = tm->tm_year - 1900;
196
197 dev_dbg(dev, "%s(): %ptR\n", __func__, tm);
198
199 return 0;
200}
201
202/*
203 * Set current time and date in RTC
204 */
205static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
206{
207 unsigned long cr;
208
209 dev_dbg(dev, "%s(): %ptR\n", __func__, tm);
210
211 wait_for_completion(&at91_rtc_upd_rdy);
212
213 /* Stop Time/Calendar from counting */
214 cr = at91_rtc_read(AT91_RTC_CR);
215 at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
216
217 at91_rtc_write_ier(AT91_RTC_ACKUPD);
218 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
219 at91_rtc_write_idr(AT91_RTC_ACKUPD);
220
221 at91_rtc_write(AT91_RTC_TIMR,
222 FIELD_PREP(AT91_RTC_SEC, bin2bcd(tm->tm_sec))
223 | FIELD_PREP(AT91_RTC_MIN, bin2bcd(tm->tm_min))
224 | FIELD_PREP(AT91_RTC_HOUR, bin2bcd(tm->tm_hour)));
225
226 at91_rtc_write(AT91_RTC_CALR,
227 FIELD_PREP(AT91_RTC_CENT,
228 bin2bcd((tm->tm_year + 1900) / 100))
229 | FIELD_PREP(AT91_RTC_YEAR, bin2bcd(tm->tm_year % 100))
230 | FIELD_PREP(AT91_RTC_MONTH, bin2bcd(tm->tm_mon + 1))
231 | FIELD_PREP(AT91_RTC_DAY, bin2bcd(tm->tm_wday + 1))
232 | FIELD_PREP(AT91_RTC_DATE, bin2bcd(tm->tm_mday)));
233
234 /* Restart Time/Calendar */
235 cr = at91_rtc_read(AT91_RTC_CR);
236 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
237 at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
238 at91_rtc_write_ier(AT91_RTC_SECEV);
239
240 return 0;
241}
242
243/*
244 * Read alarm time and date in RTC
245 */
246static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
247{
248 struct rtc_time *tm = &alrm->time;
249
250 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
251 tm->tm_year = -1;
252
253 alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
254 ? 1 : 0;
255
256 dev_dbg(dev, "%s(): %ptR %sabled\n", __func__, tm,
257 alrm->enabled ? "en" : "dis");
258
259 return 0;
260}
261
262/*
263 * Set alarm time and date in RTC
264 */
265static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
266{
267 struct rtc_time tm = alrm->time;
268
269 at91_rtc_write_idr(AT91_RTC_ALARM);
270 at91_rtc_write(AT91_RTC_TIMALR,
271 FIELD_PREP(AT91_RTC_SEC, bin2bcd(alrm->time.tm_sec))
272 | FIELD_PREP(AT91_RTC_MIN, bin2bcd(alrm->time.tm_min))
273 | FIELD_PREP(AT91_RTC_HOUR, bin2bcd(alrm->time.tm_hour))
274 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
275 at91_rtc_write(AT91_RTC_CALALR,
276 FIELD_PREP(AT91_RTC_MONTH, bin2bcd(alrm->time.tm_mon + 1))
277 | FIELD_PREP(AT91_RTC_DATE, bin2bcd(alrm->time.tm_mday))
278 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
279
280 if (alrm->enabled) {
281 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
282 at91_rtc_write_ier(AT91_RTC_ALARM);
283 }
284
285 dev_dbg(dev, "%s(): %ptR\n", __func__, &tm);
286
287 return 0;
288}
289
290static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
291{
292 dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
293
294 if (enabled) {
295 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
296 at91_rtc_write_ier(AT91_RTC_ALARM);
297 } else
298 at91_rtc_write_idr(AT91_RTC_ALARM);
299
300 return 0;
301}
302
303static int at91_rtc_readoffset(struct device *dev, long *offset)
304{
305 u32 mr = at91_rtc_read(AT91_RTC_MR);
306 long val = FIELD_GET(AT91_RTC_CORRECTION, mr);
307
308 if (!val) {
309 *offset = 0;
310 return 0;
311 }
312
313 val++;
314
315 if (!(mr & AT91_RTC_NEGPPM))
316 val = -val;
317
318 if (!(mr & AT91_RTC_HIGHPPM))
319 val *= AT91_RTC_CORR_LOW_RATIO;
320
321 *offset = DIV_ROUND_CLOSEST(AT91_RTC_CORR_DIVIDEND, val);
322
323 return 0;
324}
325
326static int at91_rtc_setoffset(struct device *dev, long offset)
327{
328 long corr;
329 u32 mr;
330
331 if (offset > AT91_RTC_CORR_DIVIDEND / 2)
332 return -ERANGE;
333 if (offset < -AT91_RTC_CORR_DIVIDEND / 2)
334 return -ERANGE;
335
336 mr = at91_rtc_read(AT91_RTC_MR);
337 mr &= ~(AT91_RTC_NEGPPM | AT91_RTC_CORRECTION | AT91_RTC_HIGHPPM);
338
339 if (offset > 0)
340 mr |= AT91_RTC_NEGPPM;
341 else
342 offset = -offset;
343
344 /* offset less than 764 ppb, disable correction*/
345 if (offset < 764) {
346 at91_rtc_write(AT91_RTC_MR, mr & ~AT91_RTC_NEGPPM);
347
348 return 0;
349 }
350
351 /*
352 * 29208 ppb is the perfect cutoff between low range and high range
353 * low range values are never better than high range value after that.
354 */
355 if (offset < 29208) {
356 corr = DIV_ROUND_CLOSEST(AT91_RTC_CORR_DIVIDEND, offset * AT91_RTC_CORR_LOW_RATIO);
357 } else {
358 corr = DIV_ROUND_CLOSEST(AT91_RTC_CORR_DIVIDEND, offset);
359 mr |= AT91_RTC_HIGHPPM;
360 }
361
362 if (corr > 128)
363 corr = 128;
364
365 mr |= FIELD_PREP(AT91_RTC_CORRECTION, corr - 1);
366
367 at91_rtc_write(AT91_RTC_MR, mr);
368
369 return 0;
370}
371
372/*
373 * IRQ handler for the RTC
374 */
375static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
376{
377 struct platform_device *pdev = dev_id;
378 struct rtc_device *rtc = platform_get_drvdata(pdev);
379 unsigned int rtsr;
380 unsigned long events = 0;
381 int ret = IRQ_NONE;
382
383 spin_lock(&suspended_lock);
384 rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
385 if (rtsr) { /* this interrupt is shared! Is it ours? */
386 if (rtsr & AT91_RTC_ALARM)
387 events |= (RTC_AF | RTC_IRQF);
388 if (rtsr & AT91_RTC_SECEV) {
389 complete(&at91_rtc_upd_rdy);
390 at91_rtc_write_idr(AT91_RTC_SECEV);
391 }
392 if (rtsr & AT91_RTC_ACKUPD)
393 complete(&at91_rtc_updated);
394
395 at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */
396
397 if (!suspended) {
398 rtc_update_irq(rtc, 1, events);
399
400 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n",
401 __func__, events >> 8, events & 0x000000FF);
402 } else {
403 cached_events |= events;
404 at91_rtc_write_idr(at91_rtc_imr);
405 pm_system_wakeup();
406 }
407
408 ret = IRQ_HANDLED;
409 }
410 spin_unlock(&suspended_lock);
411
412 return ret;
413}
414
415static const struct at91_rtc_config at91rm9200_config = {
416};
417
418static const struct at91_rtc_config at91sam9x5_config = {
419 .use_shadow_imr = true,
420};
421
422static const struct at91_rtc_config sama5d4_config = {
423 .has_correction = true,
424};
425
426static const struct of_device_id at91_rtc_dt_ids[] = {
427 {
428 .compatible = "atmel,at91rm9200-rtc",
429 .data = &at91rm9200_config,
430 }, {
431 .compatible = "atmel,at91sam9x5-rtc",
432 .data = &at91sam9x5_config,
433 }, {
434 .compatible = "atmel,sama5d4-rtc",
435 .data = &sama5d4_config,
436 }, {
437 .compatible = "atmel,sama5d2-rtc",
438 .data = &sama5d4_config,
439 }, {
440 .compatible = "microchip,sam9x60-rtc",
441 .data = &sama5d4_config,
442 }, {
443 /* sentinel */
444 }
445};
446MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
447
448static const struct rtc_class_ops at91_rtc_ops = {
449 .read_time = at91_rtc_readtime,
450 .set_time = at91_rtc_settime,
451 .read_alarm = at91_rtc_readalarm,
452 .set_alarm = at91_rtc_setalarm,
453 .alarm_irq_enable = at91_rtc_alarm_irq_enable,
454};
455
456static const struct rtc_class_ops sama5d4_rtc_ops = {
457 .read_time = at91_rtc_readtime,
458 .set_time = at91_rtc_settime,
459 .read_alarm = at91_rtc_readalarm,
460 .set_alarm = at91_rtc_setalarm,
461 .alarm_irq_enable = at91_rtc_alarm_irq_enable,
462 .set_offset = at91_rtc_setoffset,
463 .read_offset = at91_rtc_readoffset,
464};
465
466/*
467 * Initialize and install RTC driver
468 */
469static int __init at91_rtc_probe(struct platform_device *pdev)
470{
471 struct rtc_device *rtc;
472 struct resource *regs;
473 int ret = 0;
474
475 at91_rtc_config = of_device_get_match_data(&pdev->dev);
476 if (!at91_rtc_config)
477 return -ENODEV;
478
479 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
480 if (!regs) {
481 dev_err(&pdev->dev, "no mmio resource defined\n");
482 return -ENXIO;
483 }
484
485 irq = platform_get_irq(pdev, 0);
486 if (irq < 0)
487 return -ENXIO;
488
489 at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start,
490 resource_size(regs));
491 if (!at91_rtc_regs) {
492 dev_err(&pdev->dev, "failed to map registers, aborting.\n");
493 return -ENOMEM;
494 }
495
496 rtc = devm_rtc_allocate_device(&pdev->dev);
497 if (IS_ERR(rtc))
498 return PTR_ERR(rtc);
499 platform_set_drvdata(pdev, rtc);
500
501 sclk = devm_clk_get(&pdev->dev, NULL);
502 if (IS_ERR(sclk))
503 return PTR_ERR(sclk);
504
505 ret = clk_prepare_enable(sclk);
506 if (ret) {
507 dev_err(&pdev->dev, "Could not enable slow clock\n");
508 return ret;
509 }
510
511 at91_rtc_write(AT91_RTC_CR, 0);
512 at91_rtc_write(AT91_RTC_MR, at91_rtc_read(AT91_RTC_MR) & ~AT91_RTC_HRMOD);
513
514 /* Disable all interrupts */
515 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
516 AT91_RTC_SECEV | AT91_RTC_TIMEV |
517 AT91_RTC_CALEV);
518
519 ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt,
520 IRQF_SHARED | IRQF_COND_SUSPEND,
521 "at91_rtc", pdev);
522 if (ret) {
523 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
524 goto err_clk;
525 }
526
527 /* cpu init code should really have flagged this device as
528 * being wake-capable; if it didn't, do that here.
529 */
530 if (!device_can_wakeup(&pdev->dev))
531 device_init_wakeup(&pdev->dev, 1);
532
533 if (at91_rtc_config->has_correction)
534 rtc->ops = &sama5d4_rtc_ops;
535 else
536 rtc->ops = &at91_rtc_ops;
537
538 rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
539 rtc->range_max = RTC_TIMESTAMP_END_2099;
540 ret = devm_rtc_register_device(rtc);
541 if (ret)
542 goto err_clk;
543
544 /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
545 * completion.
546 */
547 at91_rtc_write_ier(AT91_RTC_SECEV);
548
549 dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
550 return 0;
551
552err_clk:
553 clk_disable_unprepare(sclk);
554
555 return ret;
556}
557
558/*
559 * Disable and remove the RTC driver
560 */
561static void __exit at91_rtc_remove(struct platform_device *pdev)
562{
563 /* Disable all interrupts */
564 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
565 AT91_RTC_SECEV | AT91_RTC_TIMEV |
566 AT91_RTC_CALEV);
567
568 clk_disable_unprepare(sclk);
569}
570
571static void at91_rtc_shutdown(struct platform_device *pdev)
572{
573 /* Disable all interrupts */
574 at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
575 AT91_RTC_SECEV | AT91_RTC_TIMEV |
576 AT91_RTC_CALEV);
577}
578
579#ifdef CONFIG_PM_SLEEP
580
581/* AT91RM9200 RTC Power management control */
582
583static int at91_rtc_suspend(struct device *dev)
584{
585 /* this IRQ is shared with DBGU and other hardware which isn't
586 * necessarily doing PM like we are...
587 */
588 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
589
590 at91_rtc_imr = at91_rtc_read_imr()
591 & (AT91_RTC_ALARM|AT91_RTC_SECEV);
592 if (at91_rtc_imr) {
593 if (device_may_wakeup(dev)) {
594 unsigned long flags;
595
596 enable_irq_wake(irq);
597
598 spin_lock_irqsave(&suspended_lock, flags);
599 suspended = true;
600 spin_unlock_irqrestore(&suspended_lock, flags);
601 } else {
602 at91_rtc_write_idr(at91_rtc_imr);
603 }
604 }
605 return 0;
606}
607
608static int at91_rtc_resume(struct device *dev)
609{
610 struct rtc_device *rtc = dev_get_drvdata(dev);
611
612 if (at91_rtc_imr) {
613 if (device_may_wakeup(dev)) {
614 unsigned long flags;
615
616 spin_lock_irqsave(&suspended_lock, flags);
617
618 if (cached_events) {
619 rtc_update_irq(rtc, 1, cached_events);
620 cached_events = 0;
621 }
622
623 suspended = false;
624 spin_unlock_irqrestore(&suspended_lock, flags);
625
626 disable_irq_wake(irq);
627 }
628 at91_rtc_write_ier(at91_rtc_imr);
629 }
630 return 0;
631}
632#endif
633
634static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
635
636/*
637 * at91_rtc_remove() lives in .exit.text. For drivers registered via
638 * module_platform_driver_probe() this is ok because they cannot get unbound at
639 * runtime. So mark the driver struct with __refdata to prevent modpost
640 * triggering a section mismatch warning.
641 */
642static struct platform_driver at91_rtc_driver __refdata = {
643 .remove_new = __exit_p(at91_rtc_remove),
644 .shutdown = at91_rtc_shutdown,
645 .driver = {
646 .name = "at91_rtc",
647 .pm = &at91_rtc_pm_ops,
648 .of_match_table = at91_rtc_dt_ids,
649 },
650};
651
652module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
653
654MODULE_AUTHOR("Rick Bronson");
655MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
656MODULE_LICENSE("GPL");
657MODULE_ALIAS("platform:at91_rtc");
1/*
2 * Real Time Clock interface for Linux on Atmel AT91RM9200
3 *
4 * Copyright (C) 2002 Rick Bronson
5 *
6 * Converted to RTC class model by Andrew Victor
7 *
8 * Ported to Linux 2.6 by Steven Scholz
9 * Based on s3c2410-rtc.c Simtec Electronics
10 *
11 * Based on sa1100-rtc.c by Nils Faerber
12 * Based on rtc.c by Paul Gortmaker
13 *
14 * This program is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU General Public License
16 * as published by the Free Software Foundation; either version
17 * 2 of the License, or (at your option) any later version.
18 *
19 */
20
21#include <linux/bcd.h>
22#include <linux/clk.h>
23#include <linux/completion.h>
24#include <linux/interrupt.h>
25#include <linux/ioctl.h>
26#include <linux/io.h>
27#include <linux/kernel.h>
28#include <linux/module.h>
29#include <linux/of_device.h>
30#include <linux/of.h>
31#include <linux/platform_device.h>
32#include <linux/rtc.h>
33#include <linux/spinlock.h>
34#include <linux/suspend.h>
35#include <linux/time.h>
36#include <linux/uaccess.h>
37
38#include "rtc-at91rm9200.h"
39
40#define at91_rtc_read(field) \
41 readl_relaxed(at91_rtc_regs + field)
42#define at91_rtc_write(field, val) \
43 writel_relaxed((val), at91_rtc_regs + field)
44
45#define AT91_RTC_EPOCH 1900UL /* just like arch/arm/common/rtctime.c */
46
47struct at91_rtc_config {
48 bool use_shadow_imr;
49};
50
51static const struct at91_rtc_config *at91_rtc_config;
52static DECLARE_COMPLETION(at91_rtc_updated);
53static DECLARE_COMPLETION(at91_rtc_upd_rdy);
54static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
55static void __iomem *at91_rtc_regs;
56static int irq;
57static DEFINE_SPINLOCK(at91_rtc_lock);
58static u32 at91_rtc_shadow_imr;
59static bool suspended;
60static DEFINE_SPINLOCK(suspended_lock);
61static unsigned long cached_events;
62static u32 at91_rtc_imr;
63static struct clk *sclk;
64
65static void at91_rtc_write_ier(u32 mask)
66{
67 unsigned long flags;
68
69 spin_lock_irqsave(&at91_rtc_lock, flags);
70 at91_rtc_shadow_imr |= mask;
71 at91_rtc_write(AT91_RTC_IER, mask);
72 spin_unlock_irqrestore(&at91_rtc_lock, flags);
73}
74
75static void at91_rtc_write_idr(u32 mask)
76{
77 unsigned long flags;
78
79 spin_lock_irqsave(&at91_rtc_lock, flags);
80 at91_rtc_write(AT91_RTC_IDR, mask);
81 /*
82 * Register read back (of any RTC-register) needed to make sure
83 * IDR-register write has reached the peripheral before updating
84 * shadow mask.
85 *
86 * Note that there is still a possibility that the mask is updated
87 * before interrupts have actually been disabled in hardware. The only
88 * way to be certain would be to poll the IMR-register, which is is
89 * the very register we are trying to emulate. The register read back
90 * is a reasonable heuristic.
91 */
92 at91_rtc_read(AT91_RTC_SR);
93 at91_rtc_shadow_imr &= ~mask;
94 spin_unlock_irqrestore(&at91_rtc_lock, flags);
95}
96
97static u32 at91_rtc_read_imr(void)
98{
99 unsigned long flags;
100 u32 mask;
101
102 if (at91_rtc_config->use_shadow_imr) {
103 spin_lock_irqsave(&at91_rtc_lock, flags);
104 mask = at91_rtc_shadow_imr;
105 spin_unlock_irqrestore(&at91_rtc_lock, flags);
106 } else {
107 mask = at91_rtc_read(AT91_RTC_IMR);
108 }
109
110 return mask;
111}
112
113/*
114 * Decode time/date into rtc_time structure
115 */
116static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
117 struct rtc_time *tm)
118{
119 unsigned int time, date;
120
121 /* must read twice in case it changes */
122 do {
123 time = at91_rtc_read(timereg);
124 date = at91_rtc_read(calreg);
125 } while ((time != at91_rtc_read(timereg)) ||
126 (date != at91_rtc_read(calreg)));
127
128 tm->tm_sec = bcd2bin((time & AT91_RTC_SEC) >> 0);
129 tm->tm_min = bcd2bin((time & AT91_RTC_MIN) >> 8);
130 tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
131
132 /*
133 * The Calendar Alarm register does not have a field for
134 * the year - so these will return an invalid value. When an
135 * alarm is set, at91_alarm_year will store the current year.
136 */
137 tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */
138 tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8); /* year */
139
140 tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
141 tm->tm_mon = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
142 tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
143}
144
145/*
146 * Read current time and date in RTC
147 */
148static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
149{
150 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
151 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
152 tm->tm_year = tm->tm_year - 1900;
153
154 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
155 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
156 tm->tm_hour, tm->tm_min, tm->tm_sec);
157
158 return 0;
159}
160
161/*
162 * Set current time and date in RTC
163 */
164static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
165{
166 unsigned long cr;
167
168 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
169 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
170 tm->tm_hour, tm->tm_min, tm->tm_sec);
171
172 wait_for_completion(&at91_rtc_upd_rdy);
173
174 /* Stop Time/Calendar from counting */
175 cr = at91_rtc_read(AT91_RTC_CR);
176 at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
177
178 at91_rtc_write_ier(AT91_RTC_ACKUPD);
179 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
180 at91_rtc_write_idr(AT91_RTC_ACKUPD);
181
182 at91_rtc_write(AT91_RTC_TIMR,
183 bin2bcd(tm->tm_sec) << 0
184 | bin2bcd(tm->tm_min) << 8
185 | bin2bcd(tm->tm_hour) << 16);
186
187 at91_rtc_write(AT91_RTC_CALR,
188 bin2bcd((tm->tm_year + 1900) / 100) /* century */
189 | bin2bcd(tm->tm_year % 100) << 8 /* year */
190 | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */
191 | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */
192 | bin2bcd(tm->tm_mday) << 24);
193
194 /* Restart Time/Calendar */
195 cr = at91_rtc_read(AT91_RTC_CR);
196 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
197 at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
198 at91_rtc_write_ier(AT91_RTC_SECEV);
199
200 return 0;
201}
202
203/*
204 * Read alarm time and date in RTC
205 */
206static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
207{
208 struct rtc_time *tm = &alrm->time;
209
210 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
211 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
212 tm->tm_year = at91_alarm_year - 1900;
213
214 alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
215 ? 1 : 0;
216
217 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
218 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
219 tm->tm_hour, tm->tm_min, tm->tm_sec);
220
221 return 0;
222}
223
224/*
225 * Set alarm time and date in RTC
226 */
227static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
228{
229 struct rtc_time tm;
230
231 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
232
233 at91_alarm_year = tm.tm_year;
234
235 tm.tm_mon = alrm->time.tm_mon;
236 tm.tm_mday = alrm->time.tm_mday;
237 tm.tm_hour = alrm->time.tm_hour;
238 tm.tm_min = alrm->time.tm_min;
239 tm.tm_sec = alrm->time.tm_sec;
240
241 at91_rtc_write_idr(AT91_RTC_ALARM);
242 at91_rtc_write(AT91_RTC_TIMALR,
243 bin2bcd(tm.tm_sec) << 0
244 | bin2bcd(tm.tm_min) << 8
245 | bin2bcd(tm.tm_hour) << 16
246 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
247 at91_rtc_write(AT91_RTC_CALALR,
248 bin2bcd(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */
249 | bin2bcd(tm.tm_mday) << 24
250 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
251
252 if (alrm->enabled) {
253 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
254 at91_rtc_write_ier(AT91_RTC_ALARM);
255 }
256
257 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
258 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
259 tm.tm_min, tm.tm_sec);
260
261 return 0;
262}
263
264static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
265{
266 dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
267
268 if (enabled) {
269 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
270 at91_rtc_write_ier(AT91_RTC_ALARM);
271 } else
272 at91_rtc_write_idr(AT91_RTC_ALARM);
273
274 return 0;
275}
276/*
277 * Provide additional RTC information in /proc/driver/rtc
278 */
279static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
280{
281 unsigned long imr = at91_rtc_read_imr();
282
283 seq_printf(seq, "update_IRQ\t: %s\n",
284 (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
285 seq_printf(seq, "periodic_IRQ\t: %s\n",
286 (imr & AT91_RTC_SECEV) ? "yes" : "no");
287
288 return 0;
289}
290
291/*
292 * IRQ handler for the RTC
293 */
294static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
295{
296 struct platform_device *pdev = dev_id;
297 struct rtc_device *rtc = platform_get_drvdata(pdev);
298 unsigned int rtsr;
299 unsigned long events = 0;
300 int ret = IRQ_NONE;
301
302 spin_lock(&suspended_lock);
303 rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
304 if (rtsr) { /* this interrupt is shared! Is it ours? */
305 if (rtsr & AT91_RTC_ALARM)
306 events |= (RTC_AF | RTC_IRQF);
307 if (rtsr & AT91_RTC_SECEV) {
308 complete(&at91_rtc_upd_rdy);
309 at91_rtc_write_idr(AT91_RTC_SECEV);
310 }
311 if (rtsr & AT91_RTC_ACKUPD)
312 complete(&at91_rtc_updated);
313
314 at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */
315
316 if (!suspended) {
317 rtc_update_irq(rtc, 1, events);
318
319 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n",
320 __func__, events >> 8, events & 0x000000FF);
321 } else {
322 cached_events |= events;
323 at91_rtc_write_idr(at91_rtc_imr);
324 pm_system_wakeup();
325 }
326
327 ret = IRQ_HANDLED;
328 }
329 spin_unlock(&suspended_lock);
330
331 return ret;
332}
333
334static const struct at91_rtc_config at91rm9200_config = {
335};
336
337static const struct at91_rtc_config at91sam9x5_config = {
338 .use_shadow_imr = true,
339};
340
341#ifdef CONFIG_OF
342static const struct of_device_id at91_rtc_dt_ids[] = {
343 {
344 .compatible = "atmel,at91rm9200-rtc",
345 .data = &at91rm9200_config,
346 }, {
347 .compatible = "atmel,at91sam9x5-rtc",
348 .data = &at91sam9x5_config,
349 }, {
350 /* sentinel */
351 }
352};
353MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
354#endif
355
356static const struct at91_rtc_config *
357at91_rtc_get_config(struct platform_device *pdev)
358{
359 const struct of_device_id *match;
360
361 if (pdev->dev.of_node) {
362 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
363 if (!match)
364 return NULL;
365 return (const struct at91_rtc_config *)match->data;
366 }
367
368 return &at91rm9200_config;
369}
370
371static const struct rtc_class_ops at91_rtc_ops = {
372 .read_time = at91_rtc_readtime,
373 .set_time = at91_rtc_settime,
374 .read_alarm = at91_rtc_readalarm,
375 .set_alarm = at91_rtc_setalarm,
376 .proc = at91_rtc_proc,
377 .alarm_irq_enable = at91_rtc_alarm_irq_enable,
378};
379
380/*
381 * Initialize and install RTC driver
382 */
383static int __init at91_rtc_probe(struct platform_device *pdev)
384{
385 struct rtc_device *rtc;
386 struct resource *regs;
387 int ret = 0;
388
389 at91_rtc_config = at91_rtc_get_config(pdev);
390 if (!at91_rtc_config)
391 return -ENODEV;
392
393 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
394 if (!regs) {
395 dev_err(&pdev->dev, "no mmio resource defined\n");
396 return -ENXIO;
397 }
398
399 irq = platform_get_irq(pdev, 0);
400 if (irq < 0) {
401 dev_err(&pdev->dev, "no irq resource defined\n");
402 return -ENXIO;
403 }
404
405 at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start,
406 resource_size(regs));
407 if (!at91_rtc_regs) {
408 dev_err(&pdev->dev, "failed to map registers, aborting.\n");
409 return -ENOMEM;
410 }
411
412 sclk = devm_clk_get(&pdev->dev, NULL);
413 if (IS_ERR(sclk))
414 return PTR_ERR(sclk);
415
416 ret = clk_prepare_enable(sclk);
417 if (ret) {
418 dev_err(&pdev->dev, "Could not enable slow clock\n");
419 return ret;
420 }
421
422 at91_rtc_write(AT91_RTC_CR, 0);
423 at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */
424
425 /* Disable all interrupts */
426 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
427 AT91_RTC_SECEV | AT91_RTC_TIMEV |
428 AT91_RTC_CALEV);
429
430 ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt,
431 IRQF_SHARED | IRQF_COND_SUSPEND,
432 "at91_rtc", pdev);
433 if (ret) {
434 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
435 goto err_clk;
436 }
437
438 /* cpu init code should really have flagged this device as
439 * being wake-capable; if it didn't, do that here.
440 */
441 if (!device_can_wakeup(&pdev->dev))
442 device_init_wakeup(&pdev->dev, 1);
443
444 rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
445 &at91_rtc_ops, THIS_MODULE);
446 if (IS_ERR(rtc)) {
447 ret = PTR_ERR(rtc);
448 goto err_clk;
449 }
450 platform_set_drvdata(pdev, rtc);
451
452 /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
453 * completion.
454 */
455 at91_rtc_write_ier(AT91_RTC_SECEV);
456
457 dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
458 return 0;
459
460err_clk:
461 clk_disable_unprepare(sclk);
462
463 return ret;
464}
465
466/*
467 * Disable and remove the RTC driver
468 */
469static int __exit at91_rtc_remove(struct platform_device *pdev)
470{
471 /* Disable all interrupts */
472 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
473 AT91_RTC_SECEV | AT91_RTC_TIMEV |
474 AT91_RTC_CALEV);
475
476 clk_disable_unprepare(sclk);
477
478 return 0;
479}
480
481static void at91_rtc_shutdown(struct platform_device *pdev)
482{
483 /* Disable all interrupts */
484 at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
485 AT91_RTC_SECEV | AT91_RTC_TIMEV |
486 AT91_RTC_CALEV);
487}
488
489#ifdef CONFIG_PM_SLEEP
490
491/* AT91RM9200 RTC Power management control */
492
493static int at91_rtc_suspend(struct device *dev)
494{
495 /* this IRQ is shared with DBGU and other hardware which isn't
496 * necessarily doing PM like we are...
497 */
498 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
499
500 at91_rtc_imr = at91_rtc_read_imr()
501 & (AT91_RTC_ALARM|AT91_RTC_SECEV);
502 if (at91_rtc_imr) {
503 if (device_may_wakeup(dev)) {
504 unsigned long flags;
505
506 enable_irq_wake(irq);
507
508 spin_lock_irqsave(&suspended_lock, flags);
509 suspended = true;
510 spin_unlock_irqrestore(&suspended_lock, flags);
511 } else {
512 at91_rtc_write_idr(at91_rtc_imr);
513 }
514 }
515 return 0;
516}
517
518static int at91_rtc_resume(struct device *dev)
519{
520 struct rtc_device *rtc = dev_get_drvdata(dev);
521
522 if (at91_rtc_imr) {
523 if (device_may_wakeup(dev)) {
524 unsigned long flags;
525
526 spin_lock_irqsave(&suspended_lock, flags);
527
528 if (cached_events) {
529 rtc_update_irq(rtc, 1, cached_events);
530 cached_events = 0;
531 }
532
533 suspended = false;
534 spin_unlock_irqrestore(&suspended_lock, flags);
535
536 disable_irq_wake(irq);
537 }
538 at91_rtc_write_ier(at91_rtc_imr);
539 }
540 return 0;
541}
542#endif
543
544static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
545
546static struct platform_driver at91_rtc_driver = {
547 .remove = __exit_p(at91_rtc_remove),
548 .shutdown = at91_rtc_shutdown,
549 .driver = {
550 .name = "at91_rtc",
551 .pm = &at91_rtc_pm_ops,
552 .of_match_table = of_match_ptr(at91_rtc_dt_ids),
553 },
554};
555
556module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
557
558MODULE_AUTHOR("Rick Bronson");
559MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
560MODULE_LICENSE("GPL");
561MODULE_ALIAS("platform:at91_rtc");