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