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/ioctl.h>
29 #include <linux/completion.h>
32 #include <linux/of_device.h>
34 #include <asm/uaccess.h>
36 #include "rtc-at91rm9200.h"
38 #define at91_rtc_read(field) \
39 __raw_readl(at91_rtc_regs + field)
40 #define at91_rtc_write(field, val) \
41 __raw_writel((val), at91_rtc_regs + field)
43 #define AT91_RTC_EPOCH 1900UL /* just like arch/arm/common/rtctime.c */
45 static DECLARE_COMPLETION(at91_rtc_updated);
46 static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
47 static void __iomem *at91_rtc_regs;
51 * Decode time/date into rtc_time structure
53 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
56 unsigned int time, date;
58 /* must read twice in case it changes */
60 time = at91_rtc_read(timereg);
61 date = at91_rtc_read(calreg);
62 } while ((time != at91_rtc_read(timereg)) ||
63 (date != at91_rtc_read(calreg)));
65 tm->tm_sec = bcd2bin((time & AT91_RTC_SEC) >> 0);
66 tm->tm_min = bcd2bin((time & AT91_RTC_MIN) >> 8);
67 tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
70 * The Calendar Alarm register does not have a field for
71 * the year - so these will return an invalid value. When an
72 * alarm is set, at91_alarm_year will store the current year.
74 tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */
75 tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8); /* year */
77 tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
78 tm->tm_mon = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
79 tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
83 * Read current time and date in RTC
85 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
87 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
88 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
89 tm->tm_year = tm->tm_year - 1900;
91 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
92 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
93 tm->tm_hour, tm->tm_min, tm->tm_sec);
99 * Set current time and date in RTC
101 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
105 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
106 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
107 tm->tm_hour, tm->tm_min, tm->tm_sec);
109 /* Stop Time/Calendar from counting */
110 cr = at91_rtc_read(AT91_RTC_CR);
111 at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
113 at91_rtc_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
114 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
115 at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);
117 at91_rtc_write(AT91_RTC_TIMR,
118 bin2bcd(tm->tm_sec) << 0
119 | bin2bcd(tm->tm_min) << 8
120 | bin2bcd(tm->tm_hour) << 16);
122 at91_rtc_write(AT91_RTC_CALR,
123 bin2bcd((tm->tm_year + 1900) / 100) /* century */
124 | bin2bcd(tm->tm_year % 100) << 8 /* year */
125 | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */
126 | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */
127 | bin2bcd(tm->tm_mday) << 24);
129 /* Restart Time/Calendar */
130 cr = at91_rtc_read(AT91_RTC_CR);
131 at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
137 * Read alarm time and date in RTC
139 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
141 struct rtc_time *tm = &alrm->time;
143 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
144 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
145 tm->tm_year = at91_alarm_year - 1900;
147 alrm->enabled = (at91_rtc_read(AT91_RTC_IMR) & AT91_RTC_ALARM)
150 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
151 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
152 tm->tm_hour, tm->tm_min, tm->tm_sec);
158 * Set alarm time and date in RTC
160 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
164 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
166 at91_alarm_year = tm.tm_year;
168 tm.tm_hour = alrm->time.tm_hour;
169 tm.tm_min = alrm->time.tm_min;
170 tm.tm_sec = alrm->time.tm_sec;
172 at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
173 at91_rtc_write(AT91_RTC_TIMALR,
174 bin2bcd(tm.tm_sec) << 0
175 | bin2bcd(tm.tm_min) << 8
176 | bin2bcd(tm.tm_hour) << 16
177 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
178 at91_rtc_write(AT91_RTC_CALALR,
179 bin2bcd(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */
180 | bin2bcd(tm.tm_mday) << 24
181 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
184 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
185 at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
188 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
189 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
190 tm.tm_min, tm.tm_sec);
195 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
197 dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
200 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
201 at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
203 at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
208 * Provide additional RTC information in /proc/driver/rtc
210 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
212 unsigned long imr = at91_rtc_read(AT91_RTC_IMR);
214 seq_printf(seq, "update_IRQ\t: %s\n",
215 (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
216 seq_printf(seq, "periodic_IRQ\t: %s\n",
217 (imr & AT91_RTC_SECEV) ? "yes" : "no");
223 * IRQ handler for the RTC
225 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
227 struct platform_device *pdev = dev_id;
228 struct rtc_device *rtc = platform_get_drvdata(pdev);
230 unsigned long events = 0;
232 rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read(AT91_RTC_IMR);
233 if (rtsr) { /* this interrupt is shared! Is it ours? */
234 if (rtsr & AT91_RTC_ALARM)
235 events |= (RTC_AF | RTC_IRQF);
236 if (rtsr & AT91_RTC_SECEV)
237 events |= (RTC_UF | RTC_IRQF);
238 if (rtsr & AT91_RTC_ACKUPD)
239 complete(&at91_rtc_updated);
241 at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */
243 rtc_update_irq(rtc, 1, events);
245 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", __func__,
246 events >> 8, events & 0x000000FF);
250 return IRQ_NONE; /* not handled */
253 static const struct rtc_class_ops at91_rtc_ops = {
254 .read_time = at91_rtc_readtime,
255 .set_time = at91_rtc_settime,
256 .read_alarm = at91_rtc_readalarm,
257 .set_alarm = at91_rtc_setalarm,
258 .proc = at91_rtc_proc,
259 .alarm_irq_enable = at91_rtc_alarm_irq_enable,
263 * Initialize and install RTC driver
265 static int __init at91_rtc_probe(struct platform_device *pdev)
267 struct rtc_device *rtc;
268 struct resource *regs;
271 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
273 dev_err(&pdev->dev, "no mmio resource defined\n");
277 irq = platform_get_irq(pdev, 0);
279 dev_err(&pdev->dev, "no irq resource defined\n");
283 at91_rtc_regs = ioremap(regs->start, resource_size(regs));
284 if (!at91_rtc_regs) {
285 dev_err(&pdev->dev, "failed to map registers, aborting.\n");
289 at91_rtc_write(AT91_RTC_CR, 0);
290 at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */
292 /* Disable all interrupts */
293 at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
294 AT91_RTC_SECEV | AT91_RTC_TIMEV |
297 ret = request_irq(irq, at91_rtc_interrupt,
301 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
305 /* cpu init code should really have flagged this device as
306 * being wake-capable; if it didn't, do that here.
308 if (!device_can_wakeup(&pdev->dev))
309 device_init_wakeup(&pdev->dev, 1);
311 rtc = rtc_device_register(pdev->name, &pdev->dev,
312 &at91_rtc_ops, THIS_MODULE);
317 platform_set_drvdata(pdev, rtc);
319 dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
325 iounmap(at91_rtc_regs);
331 * Disable and remove the RTC driver
333 static int __exit at91_rtc_remove(struct platform_device *pdev)
335 struct rtc_device *rtc = platform_get_drvdata(pdev);
337 /* Disable all interrupts */
338 at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
339 AT91_RTC_SECEV | AT91_RTC_TIMEV |
343 rtc_device_unregister(rtc);
344 iounmap(at91_rtc_regs);
345 platform_set_drvdata(pdev, NULL);
350 #ifdef CONFIG_PM_SLEEP
352 /* AT91RM9200 RTC Power management control */
354 static u32 at91_rtc_imr;
356 static int at91_rtc_suspend(struct device *dev)
358 /* this IRQ is shared with DBGU and other hardware which isn't
359 * necessarily doing PM like we are...
361 at91_rtc_imr = at91_rtc_read(AT91_RTC_IMR)
362 & (AT91_RTC_ALARM|AT91_RTC_SECEV);
364 if (device_may_wakeup(dev))
365 enable_irq_wake(irq);
367 at91_rtc_write(AT91_RTC_IDR, at91_rtc_imr);
372 static int at91_rtc_resume(struct device *dev)
375 if (device_may_wakeup(dev))
376 disable_irq_wake(irq);
378 at91_rtc_write(AT91_RTC_IER, at91_rtc_imr);
384 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
386 static const struct of_device_id at91_rtc_dt_ids[] = {
387 { .compatible = "atmel,at91rm9200-rtc" },
390 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
392 static struct platform_driver at91_rtc_driver = {
393 .remove = __exit_p(at91_rtc_remove),
396 .owner = THIS_MODULE,
397 .pm = &at91_rtc_pm_ops,
398 .of_match_table = of_match_ptr(at91_rtc_dt_ids),
402 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
404 MODULE_AUTHOR("Rick Bronson");
405 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
406 MODULE_LICENSE("GPL");
407 MODULE_ALIAS("platform:at91_rtc");