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>
31 #include <asm/uaccess.h>
33 #include <mach/at91_rtc.h>
36 #define AT91_RTC_EPOCH 1900UL /* just like arch/arm/common/rtctime.c */
38 static DECLARE_COMPLETION(at91_rtc_updated);
39 static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
42 * Decode time/date into rtc_time structure
44 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
47 unsigned int time, date;
49 /* must read twice in case it changes */
51 time = at91_sys_read(timereg);
52 date = at91_sys_read(calreg);
53 } while ((time != at91_sys_read(timereg)) ||
54 (date != at91_sys_read(calreg)));
56 tm->tm_sec = bcd2bin((time & AT91_RTC_SEC) >> 0);
57 tm->tm_min = bcd2bin((time & AT91_RTC_MIN) >> 8);
58 tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
61 * The Calendar Alarm register does not have a field for
62 * the year - so these will return an invalid value. When an
63 * alarm is set, at91_alarm_year wille store the current year.
65 tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */
66 tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8); /* year */
68 tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
69 tm->tm_mon = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
70 tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
74 * Read current time and date in RTC
76 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
78 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
79 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
80 tm->tm_year = tm->tm_year - 1900;
82 pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
83 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
84 tm->tm_hour, tm->tm_min, tm->tm_sec);
90 * Set current time and date in RTC
92 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
96 pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
97 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
98 tm->tm_hour, tm->tm_min, tm->tm_sec);
100 /* Stop Time/Calendar from counting */
101 cr = at91_sys_read(AT91_RTC_CR);
102 at91_sys_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
104 at91_sys_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
105 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
106 at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);
108 at91_sys_write(AT91_RTC_TIMR,
109 bin2bcd(tm->tm_sec) << 0
110 | bin2bcd(tm->tm_min) << 8
111 | bin2bcd(tm->tm_hour) << 16);
113 at91_sys_write(AT91_RTC_CALR,
114 bin2bcd((tm->tm_year + 1900) / 100) /* century */
115 | bin2bcd(tm->tm_year % 100) << 8 /* year */
116 | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */
117 | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */
118 | bin2bcd(tm->tm_mday) << 24);
120 /* Restart Time/Calendar */
121 cr = at91_sys_read(AT91_RTC_CR);
122 at91_sys_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
128 * Read alarm time and date in RTC
130 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
132 struct rtc_time *tm = &alrm->time;
134 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
135 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
136 tm->tm_year = at91_alarm_year - 1900;
138 alrm->enabled = (at91_sys_read(AT91_RTC_IMR) & AT91_RTC_ALARM)
141 pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
142 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
143 tm->tm_hour, tm->tm_min, tm->tm_sec);
149 * Set alarm time and date in RTC
151 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
155 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
157 at91_alarm_year = tm.tm_year;
159 tm.tm_hour = alrm->time.tm_hour;
160 tm.tm_min = alrm->time.tm_min;
161 tm.tm_sec = alrm->time.tm_sec;
163 at91_sys_write(AT91_RTC_IDR, AT91_RTC_ALARM);
164 at91_sys_write(AT91_RTC_TIMALR,
165 bin2bcd(tm.tm_sec) << 0
166 | bin2bcd(tm.tm_min) << 8
167 | bin2bcd(tm.tm_hour) << 16
168 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
169 at91_sys_write(AT91_RTC_CALALR,
170 bin2bcd(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */
171 | bin2bcd(tm.tm_mday) << 24
172 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
175 at91_sys_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
176 at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM);
179 pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
180 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
181 tm.tm_min, tm.tm_sec);
187 * Handle commands from user-space
189 static int at91_rtc_ioctl(struct device *dev, unsigned int cmd,
194 pr_debug("%s(): cmd=%08x, arg=%08lx.\n", __func__, cmd, arg);
196 /* important: scrub old status before enabling IRQs */
198 case RTC_UIE_OFF: /* update off */
199 at91_sys_write(AT91_RTC_IDR, AT91_RTC_SECEV);
201 case RTC_UIE_ON: /* update on */
202 at91_sys_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
203 at91_sys_write(AT91_RTC_IER, AT91_RTC_SECEV);
213 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
215 pr_debug("%s(): cmd=%08x\n", __func__, enabled);
218 at91_sys_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
219 at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM);
221 at91_sys_write(AT91_RTC_IDR, AT91_RTC_ALARM);
226 * Provide additional RTC information in /proc/driver/rtc
228 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
230 unsigned long imr = at91_sys_read(AT91_RTC_IMR);
232 seq_printf(seq, "update_IRQ\t: %s\n",
233 (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
234 seq_printf(seq, "periodic_IRQ\t: %s\n",
235 (imr & AT91_RTC_SECEV) ? "yes" : "no");
241 * IRQ handler for the RTC
243 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
245 struct platform_device *pdev = dev_id;
246 struct rtc_device *rtc = platform_get_drvdata(pdev);
248 unsigned long events = 0;
250 rtsr = at91_sys_read(AT91_RTC_SR) & at91_sys_read(AT91_RTC_IMR);
251 if (rtsr) { /* this interrupt is shared! Is it ours? */
252 if (rtsr & AT91_RTC_ALARM)
253 events |= (RTC_AF | RTC_IRQF);
254 if (rtsr & AT91_RTC_SECEV)
255 events |= (RTC_UF | RTC_IRQF);
256 if (rtsr & AT91_RTC_ACKUPD)
257 complete(&at91_rtc_updated);
259 at91_sys_write(AT91_RTC_SCCR, rtsr); /* clear status reg */
261 rtc_update_irq(rtc, 1, events);
263 pr_debug("%s(): num=%ld, events=0x%02lx\n", __func__,
264 events >> 8, events & 0x000000FF);
268 return IRQ_NONE; /* not handled */
271 static const struct rtc_class_ops at91_rtc_ops = {
272 .ioctl = at91_rtc_ioctl,
273 .read_time = at91_rtc_readtime,
274 .set_time = at91_rtc_settime,
275 .read_alarm = at91_rtc_readalarm,
276 .set_alarm = at91_rtc_setalarm,
277 .proc = at91_rtc_proc,
278 .alarm_irq_enable = at91_rtc_alarm_irq_enable,
282 * Initialize and install RTC driver
284 static int __init at91_rtc_probe(struct platform_device *pdev)
286 struct rtc_device *rtc;
289 at91_sys_write(AT91_RTC_CR, 0);
290 at91_sys_write(AT91_RTC_MR, 0); /* 24 hour mode */
292 /* Disable all interrupts */
293 at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
294 AT91_RTC_SECEV | AT91_RTC_TIMEV |
297 ret = request_irq(AT91_ID_SYS, at91_rtc_interrupt,
301 printk(KERN_ERR "at91_rtc: IRQ %d already in use.\n",
306 /* cpu init code should really have flagged this device as
307 * being wake-capable; if it didn't, do that here.
309 if (!device_can_wakeup(&pdev->dev))
310 device_init_wakeup(&pdev->dev, 1);
312 rtc = rtc_device_register(pdev->name, &pdev->dev,
313 &at91_rtc_ops, THIS_MODULE);
315 free_irq(AT91_ID_SYS, pdev);
318 platform_set_drvdata(pdev, rtc);
320 printk(KERN_INFO "AT91 Real Time Clock driver.\n");
325 * Disable and remove the RTC driver
327 static int __exit at91_rtc_remove(struct platform_device *pdev)
329 struct rtc_device *rtc = platform_get_drvdata(pdev);
331 /* Disable all interrupts */
332 at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
333 AT91_RTC_SECEV | AT91_RTC_TIMEV |
335 free_irq(AT91_ID_SYS, pdev);
337 rtc_device_unregister(rtc);
338 platform_set_drvdata(pdev, NULL);
345 /* AT91RM9200 RTC Power management control */
347 static u32 at91_rtc_imr;
349 static int at91_rtc_suspend(struct device *dev)
351 /* this IRQ is shared with DBGU and other hardware which isn't
352 * necessarily doing PM like we are...
354 at91_rtc_imr = at91_sys_read(AT91_RTC_IMR)
355 & (AT91_RTC_ALARM|AT91_RTC_SECEV);
357 if (device_may_wakeup(dev))
358 enable_irq_wake(AT91_ID_SYS);
360 at91_sys_write(AT91_RTC_IDR, at91_rtc_imr);
365 static int at91_rtc_resume(struct device *dev)
368 if (device_may_wakeup(dev))
369 disable_irq_wake(AT91_ID_SYS);
371 at91_sys_write(AT91_RTC_IER, at91_rtc_imr);
376 static const struct dev_pm_ops at91_rtc_pm = {
377 .suspend = at91_rtc_suspend,
378 .resume = at91_rtc_resume,
381 #define at91_rtc_pm_ptr &at91_rtc_pm
384 #define at91_rtc_pm_ptr NULL
387 static struct platform_driver at91_rtc_driver = {
388 .remove = __exit_p(at91_rtc_remove),
391 .owner = THIS_MODULE,
392 .pm = at91_rtc_pm_ptr,
396 static int __init at91_rtc_init(void)
398 return platform_driver_probe(&at91_rtc_driver, at91_rtc_probe);
401 static void __exit at91_rtc_exit(void)
403 platform_driver_unregister(&at91_rtc_driver);
406 module_init(at91_rtc_init);
407 module_exit(at91_rtc_exit);
409 MODULE_AUTHOR("Rick Bronson");
410 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
411 MODULE_LICENSE("GPL");
412 MODULE_ALIAS("platform:at91_rtc");