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>
35 #include <asm/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;
59 static void at91_rtc_write_ier(u32 mask)
63 spin_lock_irqsave(&at91_rtc_lock, flags);
64 at91_rtc_shadow_imr |= mask;
65 at91_rtc_write(AT91_RTC_IER, mask);
66 spin_unlock_irqrestore(&at91_rtc_lock, flags);
69 static void at91_rtc_write_idr(u32 mask)
73 spin_lock_irqsave(&at91_rtc_lock, flags);
74 at91_rtc_write(AT91_RTC_IDR, mask);
76 * Register read back (of any RTC-register) needed to make sure
77 * IDR-register write has reached the peripheral before updating
80 * Note that there is still a possibility that the mask is updated
81 * before interrupts have actually been disabled in hardware. The only
82 * way to be certain would be to poll the IMR-register, which is is
83 * the very register we are trying to emulate. The register read back
84 * is a reasonable heuristic.
86 at91_rtc_read(AT91_RTC_SR);
87 at91_rtc_shadow_imr &= ~mask;
88 spin_unlock_irqrestore(&at91_rtc_lock, flags);
91 static u32 at91_rtc_read_imr(void)
96 if (at91_rtc_config->use_shadow_imr) {
97 spin_lock_irqsave(&at91_rtc_lock, flags);
98 mask = at91_rtc_shadow_imr;
99 spin_unlock_irqrestore(&at91_rtc_lock, flags);
101 mask = at91_rtc_read(AT91_RTC_IMR);
108 * Decode time/date into rtc_time structure
110 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
113 unsigned int time, date;
115 /* must read twice in case it changes */
117 time = at91_rtc_read(timereg);
118 date = at91_rtc_read(calreg);
119 } while ((time != at91_rtc_read(timereg)) ||
120 (date != at91_rtc_read(calreg)));
122 tm->tm_sec = bcd2bin((time & AT91_RTC_SEC) >> 0);
123 tm->tm_min = bcd2bin((time & AT91_RTC_MIN) >> 8);
124 tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
127 * The Calendar Alarm register does not have a field for
128 * the year - so these will return an invalid value. When an
129 * alarm is set, at91_alarm_year will store the current year.
131 tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */
132 tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8); /* year */
134 tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
135 tm->tm_mon = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
136 tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
140 * Read current time and date in RTC
142 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
144 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
145 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
146 tm->tm_year = tm->tm_year - 1900;
148 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
149 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
150 tm->tm_hour, tm->tm_min, tm->tm_sec);
156 * Set current time and date in RTC
158 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
162 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
163 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
164 tm->tm_hour, tm->tm_min, tm->tm_sec);
166 wait_for_completion(&at91_rtc_upd_rdy);
168 /* Stop Time/Calendar from counting */
169 cr = at91_rtc_read(AT91_RTC_CR);
170 at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
172 at91_rtc_write_ier(AT91_RTC_ACKUPD);
173 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
174 at91_rtc_write_idr(AT91_RTC_ACKUPD);
176 at91_rtc_write(AT91_RTC_TIMR,
177 bin2bcd(tm->tm_sec) << 0
178 | bin2bcd(tm->tm_min) << 8
179 | bin2bcd(tm->tm_hour) << 16);
181 at91_rtc_write(AT91_RTC_CALR,
182 bin2bcd((tm->tm_year + 1900) / 100) /* century */
183 | bin2bcd(tm->tm_year % 100) << 8 /* year */
184 | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */
185 | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */
186 | bin2bcd(tm->tm_mday) << 24);
188 /* Restart Time/Calendar */
189 cr = at91_rtc_read(AT91_RTC_CR);
190 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
191 at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
192 at91_rtc_write_ier(AT91_RTC_SECEV);
198 * Read alarm time and date in RTC
200 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
202 struct rtc_time *tm = &alrm->time;
204 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
205 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
206 tm->tm_year = at91_alarm_year - 1900;
208 alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
211 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
212 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
213 tm->tm_hour, tm->tm_min, tm->tm_sec);
219 * Set alarm time and date in RTC
221 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
225 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
227 at91_alarm_year = tm.tm_year;
229 tm.tm_mon = alrm->time.tm_mon;
230 tm.tm_mday = alrm->time.tm_mday;
231 tm.tm_hour = alrm->time.tm_hour;
232 tm.tm_min = alrm->time.tm_min;
233 tm.tm_sec = alrm->time.tm_sec;
235 at91_rtc_write_idr(AT91_RTC_ALARM);
236 at91_rtc_write(AT91_RTC_TIMALR,
237 bin2bcd(tm.tm_sec) << 0
238 | bin2bcd(tm.tm_min) << 8
239 | bin2bcd(tm.tm_hour) << 16
240 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
241 at91_rtc_write(AT91_RTC_CALALR,
242 bin2bcd(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */
243 | bin2bcd(tm.tm_mday) << 24
244 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
247 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
248 at91_rtc_write_ier(AT91_RTC_ALARM);
251 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
252 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
253 tm.tm_min, tm.tm_sec);
258 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
260 dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
263 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
264 at91_rtc_write_ier(AT91_RTC_ALARM);
266 at91_rtc_write_idr(AT91_RTC_ALARM);
271 * Provide additional RTC information in /proc/driver/rtc
273 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
275 unsigned long imr = at91_rtc_read_imr();
277 seq_printf(seq, "update_IRQ\t: %s\n",
278 (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
279 seq_printf(seq, "periodic_IRQ\t: %s\n",
280 (imr & AT91_RTC_SECEV) ? "yes" : "no");
286 * IRQ handler for the RTC
288 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
290 struct platform_device *pdev = dev_id;
291 struct rtc_device *rtc = platform_get_drvdata(pdev);
293 unsigned long events = 0;
295 rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
296 if (rtsr) { /* this interrupt is shared! Is it ours? */
297 if (rtsr & AT91_RTC_ALARM)
298 events |= (RTC_AF | RTC_IRQF);
299 if (rtsr & AT91_RTC_SECEV) {
300 complete(&at91_rtc_upd_rdy);
301 at91_rtc_write_idr(AT91_RTC_SECEV);
303 if (rtsr & AT91_RTC_ACKUPD)
304 complete(&at91_rtc_updated);
306 at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */
308 rtc_update_irq(rtc, 1, events);
310 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", __func__,
311 events >> 8, events & 0x000000FF);
315 return IRQ_NONE; /* not handled */
318 static const struct at91_rtc_config at91rm9200_config = {
321 static const struct at91_rtc_config at91sam9x5_config = {
322 .use_shadow_imr = true,
326 static const struct of_device_id at91_rtc_dt_ids[] = {
328 .compatible = "atmel,at91rm9200-rtc",
329 .data = &at91rm9200_config,
331 .compatible = "atmel,at91sam9x5-rtc",
332 .data = &at91sam9x5_config,
337 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
340 static const struct at91_rtc_config *
341 at91_rtc_get_config(struct platform_device *pdev)
343 const struct of_device_id *match;
345 if (pdev->dev.of_node) {
346 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
349 return (const struct at91_rtc_config *)match->data;
352 return &at91rm9200_config;
355 static const struct rtc_class_ops at91_rtc_ops = {
356 .read_time = at91_rtc_readtime,
357 .set_time = at91_rtc_settime,
358 .read_alarm = at91_rtc_readalarm,
359 .set_alarm = at91_rtc_setalarm,
360 .proc = at91_rtc_proc,
361 .alarm_irq_enable = at91_rtc_alarm_irq_enable,
365 * Initialize and install RTC driver
367 static int __init at91_rtc_probe(struct platform_device *pdev)
369 struct rtc_device *rtc;
370 struct resource *regs;
373 at91_rtc_config = at91_rtc_get_config(pdev);
374 if (!at91_rtc_config)
377 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
379 dev_err(&pdev->dev, "no mmio resource defined\n");
383 irq = platform_get_irq(pdev, 0);
385 dev_err(&pdev->dev, "no irq resource defined\n");
389 at91_rtc_regs = ioremap(regs->start, resource_size(regs));
390 if (!at91_rtc_regs) {
391 dev_err(&pdev->dev, "failed to map registers, aborting.\n");
395 at91_rtc_write(AT91_RTC_CR, 0);
396 at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */
398 /* Disable all interrupts */
399 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
400 AT91_RTC_SECEV | AT91_RTC_TIMEV |
403 ret = request_irq(irq, at91_rtc_interrupt,
407 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
411 /* cpu init code should really have flagged this device as
412 * being wake-capable; if it didn't, do that here.
414 if (!device_can_wakeup(&pdev->dev))
415 device_init_wakeup(&pdev->dev, 1);
417 rtc = rtc_device_register(pdev->name, &pdev->dev,
418 &at91_rtc_ops, THIS_MODULE);
423 platform_set_drvdata(pdev, rtc);
425 /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
428 at91_rtc_write_ier(AT91_RTC_SECEV);
430 dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
436 iounmap(at91_rtc_regs);
442 * Disable and remove the RTC driver
444 static int __exit at91_rtc_remove(struct platform_device *pdev)
446 struct rtc_device *rtc = platform_get_drvdata(pdev);
448 /* Disable all interrupts */
449 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
450 AT91_RTC_SECEV | AT91_RTC_TIMEV |
454 rtc_device_unregister(rtc);
455 iounmap(at91_rtc_regs);
456 platform_set_drvdata(pdev, NULL);
461 #ifdef CONFIG_PM_SLEEP
463 /* AT91RM9200 RTC Power management control */
465 static u32 at91_rtc_imr;
467 static int at91_rtc_suspend(struct device *dev)
469 /* this IRQ is shared with DBGU and other hardware which isn't
470 * necessarily doing PM like we are...
472 at91_rtc_imr = at91_rtc_read_imr()
473 & (AT91_RTC_ALARM|AT91_RTC_SECEV);
475 if (device_may_wakeup(dev))
476 enable_irq_wake(irq);
478 at91_rtc_write_idr(at91_rtc_imr);
483 static int at91_rtc_resume(struct device *dev)
486 if (device_may_wakeup(dev))
487 disable_irq_wake(irq);
489 at91_rtc_write_ier(at91_rtc_imr);
495 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
497 static struct platform_driver at91_rtc_driver = {
498 .remove = __exit_p(at91_rtc_remove),
501 .owner = THIS_MODULE,
502 .pm = &at91_rtc_pm_ops,
503 .of_match_table = of_match_ptr(at91_rtc_dt_ids),
507 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
509 MODULE_AUTHOR("Rick Bronson");
510 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
511 MODULE_LICENSE("GPL");
512 MODULE_ALIAS("platform:at91_rtc");