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 unsigned int at91_alarm_year = AT91_RTC_EPOCH;
53 static void __iomem *at91_rtc_regs;
55 static DEFINE_SPINLOCK(at91_rtc_lock);
56 static u32 at91_rtc_shadow_imr;
58 static void at91_rtc_write_ier(u32 mask)
62 spin_lock_irqsave(&at91_rtc_lock, flags);
63 at91_rtc_shadow_imr |= mask;
64 at91_rtc_write(AT91_RTC_IER, mask);
65 spin_unlock_irqrestore(&at91_rtc_lock, flags);
68 static void at91_rtc_write_idr(u32 mask)
72 spin_lock_irqsave(&at91_rtc_lock, flags);
73 at91_rtc_write(AT91_RTC_IDR, mask);
75 * Register read back (of any RTC-register) needed to make sure
76 * IDR-register write has reached the peripheral before updating
79 * Note that there is still a possibility that the mask is updated
80 * before interrupts have actually been disabled in hardware. The only
81 * way to be certain would be to poll the IMR-register, which is is
82 * the very register we are trying to emulate. The register read back
83 * is a reasonable heuristic.
85 at91_rtc_read(AT91_RTC_SR);
86 at91_rtc_shadow_imr &= ~mask;
87 spin_unlock_irqrestore(&at91_rtc_lock, flags);
90 static u32 at91_rtc_read_imr(void)
95 if (at91_rtc_config->use_shadow_imr) {
96 spin_lock_irqsave(&at91_rtc_lock, flags);
97 mask = at91_rtc_shadow_imr;
98 spin_unlock_irqrestore(&at91_rtc_lock, flags);
100 mask = at91_rtc_read(AT91_RTC_IMR);
107 * Decode time/date into rtc_time structure
109 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
112 unsigned int time, date;
114 /* must read twice in case it changes */
116 time = at91_rtc_read(timereg);
117 date = at91_rtc_read(calreg);
118 } while ((time != at91_rtc_read(timereg)) ||
119 (date != at91_rtc_read(calreg)));
121 tm->tm_sec = bcd2bin((time & AT91_RTC_SEC) >> 0);
122 tm->tm_min = bcd2bin((time & AT91_RTC_MIN) >> 8);
123 tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
126 * The Calendar Alarm register does not have a field for
127 * the year - so these will return an invalid value. When an
128 * alarm is set, at91_alarm_year will store the current year.
130 tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */
131 tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8); /* year */
133 tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
134 tm->tm_mon = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
135 tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
139 * Read current time and date in RTC
141 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
143 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
144 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
145 tm->tm_year = tm->tm_year - 1900;
147 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
148 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
149 tm->tm_hour, tm->tm_min, tm->tm_sec);
155 * Set current time and date in RTC
157 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
161 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
162 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
163 tm->tm_hour, tm->tm_min, tm->tm_sec);
165 /* Stop Time/Calendar from counting */
166 cr = at91_rtc_read(AT91_RTC_CR);
167 at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
169 at91_rtc_write_ier(AT91_RTC_ACKUPD);
170 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
171 at91_rtc_write_idr(AT91_RTC_ACKUPD);
173 at91_rtc_write(AT91_RTC_TIMR,
174 bin2bcd(tm->tm_sec) << 0
175 | bin2bcd(tm->tm_min) << 8
176 | bin2bcd(tm->tm_hour) << 16);
178 at91_rtc_write(AT91_RTC_CALR,
179 bin2bcd((tm->tm_year + 1900) / 100) /* century */
180 | bin2bcd(tm->tm_year % 100) << 8 /* year */
181 | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */
182 | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */
183 | bin2bcd(tm->tm_mday) << 24);
185 /* Restart Time/Calendar */
186 cr = at91_rtc_read(AT91_RTC_CR);
187 at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
193 * Read alarm time and date in RTC
195 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
197 struct rtc_time *tm = &alrm->time;
199 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
200 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
201 tm->tm_year = at91_alarm_year - 1900;
203 alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
206 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
207 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
208 tm->tm_hour, tm->tm_min, tm->tm_sec);
214 * Set alarm time and date in RTC
216 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
220 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
222 at91_alarm_year = tm.tm_year;
224 tm.tm_mon = alrm->time.tm_mon;
225 tm.tm_mday = alrm->time.tm_mday;
226 tm.tm_hour = alrm->time.tm_hour;
227 tm.tm_min = alrm->time.tm_min;
228 tm.tm_sec = alrm->time.tm_sec;
230 at91_rtc_write_idr(AT91_RTC_ALARM);
231 at91_rtc_write(AT91_RTC_TIMALR,
232 bin2bcd(tm.tm_sec) << 0
233 | bin2bcd(tm.tm_min) << 8
234 | bin2bcd(tm.tm_hour) << 16
235 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
236 at91_rtc_write(AT91_RTC_CALALR,
237 bin2bcd(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */
238 | bin2bcd(tm.tm_mday) << 24
239 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
242 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
243 at91_rtc_write_ier(AT91_RTC_ALARM);
246 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
247 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
248 tm.tm_min, tm.tm_sec);
253 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
255 dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
258 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
259 at91_rtc_write_ier(AT91_RTC_ALARM);
261 at91_rtc_write_idr(AT91_RTC_ALARM);
266 * Provide additional RTC information in /proc/driver/rtc
268 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
270 unsigned long imr = at91_rtc_read_imr();
272 seq_printf(seq, "update_IRQ\t: %s\n",
273 (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
274 seq_printf(seq, "periodic_IRQ\t: %s\n",
275 (imr & AT91_RTC_SECEV) ? "yes" : "no");
281 * IRQ handler for the RTC
283 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
285 struct platform_device *pdev = dev_id;
286 struct rtc_device *rtc = platform_get_drvdata(pdev);
288 unsigned long events = 0;
290 rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
291 if (rtsr) { /* this interrupt is shared! Is it ours? */
292 if (rtsr & AT91_RTC_ALARM)
293 events |= (RTC_AF | RTC_IRQF);
294 if (rtsr & AT91_RTC_SECEV)
295 events |= (RTC_UF | RTC_IRQF);
296 if (rtsr & AT91_RTC_ACKUPD)
297 complete(&at91_rtc_updated);
299 at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */
301 rtc_update_irq(rtc, 1, events);
303 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", __func__,
304 events >> 8, events & 0x000000FF);
308 return IRQ_NONE; /* not handled */
311 static const struct at91_rtc_config at91rm9200_config = {
314 static const struct at91_rtc_config at91sam9x5_config = {
315 .use_shadow_imr = true,
319 static const struct of_device_id at91_rtc_dt_ids[] = {
321 .compatible = "atmel,at91rm9200-rtc",
322 .data = &at91rm9200_config,
324 .compatible = "atmel,at91sam9x5-rtc",
325 .data = &at91sam9x5_config,
330 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
333 static const struct at91_rtc_config *
334 at91_rtc_get_config(struct platform_device *pdev)
336 const struct of_device_id *match;
338 if (pdev->dev.of_node) {
339 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
342 return (const struct at91_rtc_config *)match->data;
345 return &at91rm9200_config;
348 static const struct rtc_class_ops at91_rtc_ops = {
349 .read_time = at91_rtc_readtime,
350 .set_time = at91_rtc_settime,
351 .read_alarm = at91_rtc_readalarm,
352 .set_alarm = at91_rtc_setalarm,
353 .proc = at91_rtc_proc,
354 .alarm_irq_enable = at91_rtc_alarm_irq_enable,
358 * Initialize and install RTC driver
360 static int __init at91_rtc_probe(struct platform_device *pdev)
362 struct rtc_device *rtc;
363 struct resource *regs;
366 at91_rtc_config = at91_rtc_get_config(pdev);
367 if (!at91_rtc_config)
370 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
372 dev_err(&pdev->dev, "no mmio resource defined\n");
376 irq = platform_get_irq(pdev, 0);
378 dev_err(&pdev->dev, "no irq resource defined\n");
382 at91_rtc_regs = ioremap(regs->start, resource_size(regs));
383 if (!at91_rtc_regs) {
384 dev_err(&pdev->dev, "failed to map registers, aborting.\n");
388 at91_rtc_write(AT91_RTC_CR, 0);
389 at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */
391 /* Disable all interrupts */
392 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
393 AT91_RTC_SECEV | AT91_RTC_TIMEV |
396 ret = request_irq(irq, at91_rtc_interrupt,
400 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
404 /* cpu init code should really have flagged this device as
405 * being wake-capable; if it didn't, do that here.
407 if (!device_can_wakeup(&pdev->dev))
408 device_init_wakeup(&pdev->dev, 1);
410 rtc = rtc_device_register(pdev->name, &pdev->dev,
411 &at91_rtc_ops, THIS_MODULE);
416 platform_set_drvdata(pdev, rtc);
418 dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
424 iounmap(at91_rtc_regs);
430 * Disable and remove the RTC driver
432 static int __exit at91_rtc_remove(struct platform_device *pdev)
434 struct rtc_device *rtc = platform_get_drvdata(pdev);
436 /* Disable all interrupts */
437 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
438 AT91_RTC_SECEV | AT91_RTC_TIMEV |
442 rtc_device_unregister(rtc);
443 iounmap(at91_rtc_regs);
444 platform_set_drvdata(pdev, NULL);
449 #ifdef CONFIG_PM_SLEEP
451 /* AT91RM9200 RTC Power management control */
453 static u32 at91_rtc_imr;
455 static int at91_rtc_suspend(struct device *dev)
457 /* this IRQ is shared with DBGU and other hardware which isn't
458 * necessarily doing PM like we are...
460 at91_rtc_imr = at91_rtc_read_imr()
461 & (AT91_RTC_ALARM|AT91_RTC_SECEV);
463 if (device_may_wakeup(dev))
464 enable_irq_wake(irq);
466 at91_rtc_write_idr(at91_rtc_imr);
471 static int at91_rtc_resume(struct device *dev)
474 if (device_may_wakeup(dev))
475 disable_irq_wake(irq);
477 at91_rtc_write_ier(at91_rtc_imr);
483 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
485 static struct platform_driver at91_rtc_driver = {
486 .remove = __exit_p(at91_rtc_remove),
489 .owner = THIS_MODULE,
490 .pm = &at91_rtc_pm_ops,
491 .of_match_table = of_match_ptr(at91_rtc_dt_ids),
495 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
497 MODULE_AUTHOR("Rick Bronson");
498 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
499 MODULE_LICENSE("GPL");
500 MODULE_ALIAS("platform:at91_rtc");