2 * Real Time Clock interface for Linux on Atmel AT91RM9200
4 * Copyright (C) 2002 Rick Bronson
6 * Converted to RTC class model by Andrew Victor
8 * Ported to Linux 2.6 by Steven Scholz
9 * Based on s3c2410-rtc.c Simtec Electronics
11 * Based on sa1100-rtc.c by Nils Faerber
12 * Based on rtc.c by Paul Gortmaker
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.
21 #include <linux/module.h>
22 #include <linux/kernel.h>
23 #include <linux/platform_device.h>
24 #include <linux/time.h>
25 #include <linux/rtc.h>
26 #include <linux/bcd.h>
27 #include <linux/interrupt.h>
28 #include <linux/spinlock.h>
29 #include <linux/ioctl.h>
30 #include <linux/completion.h>
33 #include <linux/of_device.h>
34 #include <linux/suspend.h>
35 #include <linux/uaccess.h>
37 #include "rtc-at91rm9200.h"
39 #define at91_rtc_read(field) \
40 __raw_readl(at91_rtc_regs + field)
41 #define at91_rtc_write(field, val) \
42 __raw_writel((val), at91_rtc_regs + field)
44 #define AT91_RTC_EPOCH 1900UL /* just like arch/arm/common/rtctime.c */
46 struct at91_rtc_config {
50 static const struct at91_rtc_config *at91_rtc_config;
51 static DECLARE_COMPLETION(at91_rtc_updated);
52 static DECLARE_COMPLETION(at91_rtc_upd_rdy);
53 static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
54 static void __iomem *at91_rtc_regs;
56 static DEFINE_SPINLOCK(at91_rtc_lock);
57 static u32 at91_rtc_shadow_imr;
58 static bool suspended;
59 static DEFINE_SPINLOCK(suspended_lock);
60 static unsigned long cached_events;
61 static u32 at91_rtc_imr;
63 static void at91_rtc_write_ier(u32 mask)
67 spin_lock_irqsave(&at91_rtc_lock, flags);
68 at91_rtc_shadow_imr |= mask;
69 at91_rtc_write(AT91_RTC_IER, mask);
70 spin_unlock_irqrestore(&at91_rtc_lock, flags);
73 static void at91_rtc_write_idr(u32 mask)
77 spin_lock_irqsave(&at91_rtc_lock, flags);
78 at91_rtc_write(AT91_RTC_IDR, mask);
80 * Register read back (of any RTC-register) needed to make sure
81 * IDR-register write has reached the peripheral before updating
84 * Note that there is still a possibility that the mask is updated
85 * before interrupts have actually been disabled in hardware. The only
86 * way to be certain would be to poll the IMR-register, which is is
87 * the very register we are trying to emulate. The register read back
88 * is a reasonable heuristic.
90 at91_rtc_read(AT91_RTC_SR);
91 at91_rtc_shadow_imr &= ~mask;
92 spin_unlock_irqrestore(&at91_rtc_lock, flags);
95 static u32 at91_rtc_read_imr(void)
100 if (at91_rtc_config->use_shadow_imr) {
101 spin_lock_irqsave(&at91_rtc_lock, flags);
102 mask = at91_rtc_shadow_imr;
103 spin_unlock_irqrestore(&at91_rtc_lock, flags);
105 mask = at91_rtc_read(AT91_RTC_IMR);
112 * Decode time/date into rtc_time structure
114 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
117 unsigned int time, date;
119 /* must read twice in case it changes */
121 time = at91_rtc_read(timereg);
122 date = at91_rtc_read(calreg);
123 } while ((time != at91_rtc_read(timereg)) ||
124 (date != at91_rtc_read(calreg)));
126 tm->tm_sec = bcd2bin((time & AT91_RTC_SEC) >> 0);
127 tm->tm_min = bcd2bin((time & AT91_RTC_MIN) >> 8);
128 tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
131 * The Calendar Alarm register does not have a field for
132 * the year - so these will return an invalid value. When an
133 * alarm is set, at91_alarm_year will store the current year.
135 tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */
136 tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8); /* year */
138 tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
139 tm->tm_mon = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
140 tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
144 * Read current time and date in RTC
146 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
148 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
149 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
150 tm->tm_year = tm->tm_year - 1900;
152 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
153 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
154 tm->tm_hour, tm->tm_min, tm->tm_sec);
160 * Set current time and date in RTC
162 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
166 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
167 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
168 tm->tm_hour, tm->tm_min, tm->tm_sec);
170 wait_for_completion(&at91_rtc_upd_rdy);
172 /* Stop Time/Calendar from counting */
173 cr = at91_rtc_read(AT91_RTC_CR);
174 at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
176 at91_rtc_write_ier(AT91_RTC_ACKUPD);
177 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
178 at91_rtc_write_idr(AT91_RTC_ACKUPD);
180 at91_rtc_write(AT91_RTC_TIMR,
181 bin2bcd(tm->tm_sec) << 0
182 | bin2bcd(tm->tm_min) << 8
183 | bin2bcd(tm->tm_hour) << 16);
185 at91_rtc_write(AT91_RTC_CALR,
186 bin2bcd((tm->tm_year + 1900) / 100) /* century */
187 | bin2bcd(tm->tm_year % 100) << 8 /* year */
188 | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */
189 | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */
190 | bin2bcd(tm->tm_mday) << 24);
192 /* Restart Time/Calendar */
193 cr = at91_rtc_read(AT91_RTC_CR);
194 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
195 at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
196 at91_rtc_write_ier(AT91_RTC_SECEV);
202 * Read alarm time and date in RTC
204 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
206 struct rtc_time *tm = &alrm->time;
208 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
209 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
210 tm->tm_year = at91_alarm_year - 1900;
212 alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
215 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
216 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
217 tm->tm_hour, tm->tm_min, tm->tm_sec);
223 * Set alarm time and date in RTC
225 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
229 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
231 at91_alarm_year = tm.tm_year;
233 tm.tm_mon = alrm->time.tm_mon;
234 tm.tm_mday = alrm->time.tm_mday;
235 tm.tm_hour = alrm->time.tm_hour;
236 tm.tm_min = alrm->time.tm_min;
237 tm.tm_sec = alrm->time.tm_sec;
239 at91_rtc_write_idr(AT91_RTC_ALARM);
240 at91_rtc_write(AT91_RTC_TIMALR,
241 bin2bcd(tm.tm_sec) << 0
242 | bin2bcd(tm.tm_min) << 8
243 | bin2bcd(tm.tm_hour) << 16
244 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
245 at91_rtc_write(AT91_RTC_CALALR,
246 bin2bcd(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */
247 | bin2bcd(tm.tm_mday) << 24
248 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
251 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
252 at91_rtc_write_ier(AT91_RTC_ALARM);
255 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
256 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
257 tm.tm_min, tm.tm_sec);
262 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
264 dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
267 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
268 at91_rtc_write_ier(AT91_RTC_ALARM);
270 at91_rtc_write_idr(AT91_RTC_ALARM);
275 * Provide additional RTC information in /proc/driver/rtc
277 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
279 unsigned long imr = at91_rtc_read_imr();
281 seq_printf(seq, "update_IRQ\t: %s\n",
282 (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
283 seq_printf(seq, "periodic_IRQ\t: %s\n",
284 (imr & AT91_RTC_SECEV) ? "yes" : "no");
290 * IRQ handler for the RTC
292 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
294 struct platform_device *pdev = dev_id;
295 struct rtc_device *rtc = platform_get_drvdata(pdev);
297 unsigned long events = 0;
300 spin_lock(&suspended_lock);
301 rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
302 if (rtsr) { /* this interrupt is shared! Is it ours? */
303 if (rtsr & AT91_RTC_ALARM)
304 events |= (RTC_AF | RTC_IRQF);
305 if (rtsr & AT91_RTC_SECEV) {
306 complete(&at91_rtc_upd_rdy);
307 at91_rtc_write_idr(AT91_RTC_SECEV);
309 if (rtsr & AT91_RTC_ACKUPD)
310 complete(&at91_rtc_updated);
312 at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */
315 rtc_update_irq(rtc, 1, events);
317 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n",
318 __func__, events >> 8, events & 0x000000FF);
320 cached_events |= events;
321 at91_rtc_write_idr(at91_rtc_imr);
327 spin_lock(&suspended_lock);
332 static const struct at91_rtc_config at91rm9200_config = {
335 static const struct at91_rtc_config at91sam9x5_config = {
336 .use_shadow_imr = true,
340 static const struct of_device_id at91_rtc_dt_ids[] = {
342 .compatible = "atmel,at91rm9200-rtc",
343 .data = &at91rm9200_config,
345 .compatible = "atmel,at91sam9x5-rtc",
346 .data = &at91sam9x5_config,
351 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
354 static const struct at91_rtc_config *
355 at91_rtc_get_config(struct platform_device *pdev)
357 const struct of_device_id *match;
359 if (pdev->dev.of_node) {
360 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
363 return (const struct at91_rtc_config *)match->data;
366 return &at91rm9200_config;
369 static const struct rtc_class_ops at91_rtc_ops = {
370 .read_time = at91_rtc_readtime,
371 .set_time = at91_rtc_settime,
372 .read_alarm = at91_rtc_readalarm,
373 .set_alarm = at91_rtc_setalarm,
374 .proc = at91_rtc_proc,
375 .alarm_irq_enable = at91_rtc_alarm_irq_enable,
379 * Initialize and install RTC driver
381 static int __init at91_rtc_probe(struct platform_device *pdev)
383 struct rtc_device *rtc;
384 struct resource *regs;
387 at91_rtc_config = at91_rtc_get_config(pdev);
388 if (!at91_rtc_config)
391 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
393 dev_err(&pdev->dev, "no mmio resource defined\n");
397 irq = platform_get_irq(pdev, 0);
399 dev_err(&pdev->dev, "no irq resource defined\n");
403 at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start,
404 resource_size(regs));
405 if (!at91_rtc_regs) {
406 dev_err(&pdev->dev, "failed to map registers, aborting.\n");
410 at91_rtc_write(AT91_RTC_CR, 0);
411 at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */
413 /* Disable all interrupts */
414 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
415 AT91_RTC_SECEV | AT91_RTC_TIMEV |
418 ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt,
419 IRQF_SHARED | IRQF_COND_SUSPEND,
422 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
426 /* cpu init code should really have flagged this device as
427 * being wake-capable; if it didn't, do that here.
429 if (!device_can_wakeup(&pdev->dev))
430 device_init_wakeup(&pdev->dev, 1);
432 rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
433 &at91_rtc_ops, THIS_MODULE);
436 platform_set_drvdata(pdev, rtc);
438 /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
441 at91_rtc_write_ier(AT91_RTC_SECEV);
443 dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
448 * Disable and remove the RTC driver
450 static int __exit at91_rtc_remove(struct platform_device *pdev)
452 /* Disable all interrupts */
453 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
454 AT91_RTC_SECEV | AT91_RTC_TIMEV |
460 static void at91_rtc_shutdown(struct platform_device *pdev)
462 /* Disable all interrupts */
463 at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
464 AT91_RTC_SECEV | AT91_RTC_TIMEV |
468 #ifdef CONFIG_PM_SLEEP
470 /* AT91RM9200 RTC Power management control */
472 static int at91_rtc_suspend(struct device *dev)
474 /* this IRQ is shared with DBGU and other hardware which isn't
475 * necessarily doing PM like we are...
477 at91_rtc_imr = at91_rtc_read_imr()
478 & (AT91_RTC_ALARM|AT91_RTC_SECEV);
480 if (device_may_wakeup(dev)) {
483 enable_irq_wake(irq);
485 spin_lock_irqsave(&suspended_lock, flags);
487 spin_unlock_irqrestore(&suspended_lock, flags);
489 at91_rtc_write_idr(at91_rtc_imr);
495 static int at91_rtc_resume(struct device *dev)
497 struct rtc_device *rtc = dev_get_drvdata(dev);
500 if (device_may_wakeup(dev)) {
503 spin_lock_irqsave(&suspended_lock, flags);
506 rtc_update_irq(rtc, 1, cached_events);
511 spin_unlock_irqrestore(&suspended_lock, flags);
513 disable_irq_wake(irq);
515 at91_rtc_write_ier(at91_rtc_imr);
521 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
523 static struct platform_driver at91_rtc_driver = {
524 .remove = __exit_p(at91_rtc_remove),
525 .shutdown = at91_rtc_shutdown,
528 .pm = &at91_rtc_pm_ops,
529 .of_match_table = of_match_ptr(at91_rtc_dt_ids),
533 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
535 MODULE_AUTHOR("Rick Bronson");
536 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
537 MODULE_LICENSE("GPL");
538 MODULE_ALIAS("platform:at91_rtc");