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>
34 #include <asm/mach/time.h>
37 #define AT91_RTC_FREQ 1
38 #define AT91_RTC_EPOCH 1900UL /* just like arch/arm/common/rtctime.c */
40 static DECLARE_COMPLETION(at91_rtc_updated);
41 static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
45 * Decode time/date into rtc_time structure
47 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg, struct rtc_time *tm)
49 unsigned int time, date;
51 /* must read twice in case it changes */
53 time = at91_sys_read(timereg);
54 date = at91_sys_read(calreg);
55 } while ((time != at91_sys_read(timereg)) || (date != at91_sys_read(calreg)));
57 tm->tm_sec = BCD2BIN((time & AT91_RTC_SEC) >> 0);
58 tm->tm_min = BCD2BIN((time & AT91_RTC_MIN) >> 8);
59 tm->tm_hour = BCD2BIN((time & AT91_RTC_HOUR) >> 16);
62 * The Calendar Alarm register does not have a field for
63 * the year - so these will return an invalid value. When an
64 * alarm is set, at91_alarm_year wille store the current year.
66 tm->tm_year = BCD2BIN(date & AT91_RTC_CENT) * 100; /* century */
67 tm->tm_year += BCD2BIN((date & AT91_RTC_YEAR) >> 8); /* year */
69 tm->tm_wday = BCD2BIN((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
70 tm->tm_mon = BCD2BIN((date & AT91_RTC_MONTH) >> 16) - 1;
71 tm->tm_mday = BCD2BIN((date & AT91_RTC_DATE) >> 24);
75 * Read current time and date in RTC
77 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
79 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
80 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
81 tm->tm_year = tm->tm_year - 1900;
83 pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __FUNCTION__,
84 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday, 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", __FUNCTION__,
97 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);
99 /* Stop Time/Calendar from counting */
100 cr = at91_sys_read(AT91_RTC_CR);
101 at91_sys_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
103 at91_sys_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
104 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
105 at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);
107 at91_sys_write(AT91_RTC_TIMR,
108 BIN2BCD(tm->tm_sec) << 0
109 | BIN2BCD(tm->tm_min) << 8
110 | BIN2BCD(tm->tm_hour) << 16);
112 at91_sys_write(AT91_RTC_CALR,
113 BIN2BCD((tm->tm_year + 1900) / 100) /* century */
114 | BIN2BCD(tm->tm_year % 100) << 8 /* year */
115 | BIN2BCD(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */
116 | BIN2BCD(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */
117 | BIN2BCD(tm->tm_mday) << 24);
119 /* Restart Time/Calendar */
120 cr = at91_sys_read(AT91_RTC_CR);
121 at91_sys_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
127 * Read alarm time and date in RTC
129 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
131 struct rtc_time *tm = &alrm->time;
133 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
134 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
135 tm->tm_year = at91_alarm_year - 1900;
137 pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __FUNCTION__,
138 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);
144 * Set alarm time and date in RTC
146 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
150 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
152 at91_alarm_year = tm.tm_year;
154 tm.tm_hour = alrm->time.tm_hour;
155 tm.tm_min = alrm->time.tm_min;
156 tm.tm_sec = alrm->time.tm_sec;
158 at91_sys_write(AT91_RTC_TIMALR,
159 BIN2BCD(tm.tm_sec) << 0
160 | BIN2BCD(tm.tm_min) << 8
161 | BIN2BCD(tm.tm_hour) << 16
162 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
163 at91_sys_write(AT91_RTC_CALALR,
164 BIN2BCD(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */
165 | BIN2BCD(tm.tm_mday) << 24
166 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
168 pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __FUNCTION__,
169 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
175 * Handle commands from user-space
177 static int at91_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
181 pr_debug("%s(): cmd=%08x, arg=%08lx.\n", __FUNCTION__, cmd, arg);
184 case RTC_AIE_OFF: /* alarm off */
185 at91_sys_write(AT91_RTC_IDR, AT91_RTC_ALARM);
187 case RTC_AIE_ON: /* alarm on */
188 at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM);
190 case RTC_UIE_OFF: /* update off */
191 case RTC_PIE_OFF: /* periodic off */
192 at91_sys_write(AT91_RTC_IDR, AT91_RTC_SECEV);
194 case RTC_UIE_ON: /* update on */
195 case RTC_PIE_ON: /* periodic on */
196 at91_sys_write(AT91_RTC_IER, AT91_RTC_SECEV);
198 case RTC_IRQP_READ: /* read periodic alarm frequency */
199 ret = put_user(AT91_RTC_FREQ, (unsigned long *) arg);
201 case RTC_IRQP_SET: /* set periodic alarm frequency */
202 if (arg != AT91_RTC_FREQ)
214 * Provide additional RTC information in /proc/driver/rtc
216 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
218 unsigned long imr = at91_sys_read(AT91_RTC_IMR);
220 seq_printf(seq, "alarm_IRQ\t: %s\n", (imr & AT91_RTC_ALARM) ? "yes" : "no");
221 seq_printf(seq, "update_IRQ\t: %s\n", (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
222 seq_printf(seq, "periodic_IRQ\t: %s\n", (imr & AT91_RTC_SECEV) ? "yes" : "no");
223 seq_printf(seq, "periodic_freq\t: %ld\n", (unsigned long) AT91_RTC_FREQ);
229 * IRQ handler for the RTC
231 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs)
233 struct platform_device *pdev = (struct platform_device *)dev_id;
234 struct rtc_device *rtc = platform_get_drvdata(pdev);
236 unsigned long events = 0;
238 rtsr = at91_sys_read(AT91_RTC_SR) & at91_sys_read(AT91_RTC_IMR);
239 if (rtsr) { /* this interrupt is shared! Is it ours? */
240 if (rtsr & AT91_RTC_ALARM)
241 events |= (RTC_AF | RTC_IRQF);
242 if (rtsr & AT91_RTC_SECEV)
243 events |= (RTC_UF | RTC_IRQF);
244 if (rtsr & AT91_RTC_ACKUPD)
245 complete(&at91_rtc_updated);
247 at91_sys_write(AT91_RTC_SCCR, rtsr); /* clear status reg */
249 rtc_update_irq(&rtc->class_dev, 1, events);
251 pr_debug("%s(): num=%ld, events=0x%02lx\n", __FUNCTION__,
252 events >> 8, events & 0x000000FF);
256 return IRQ_NONE; /* not handled */
259 static struct rtc_class_ops at91_rtc_ops = {
260 .ioctl = at91_rtc_ioctl,
261 .read_time = at91_rtc_readtime,
262 .set_time = at91_rtc_settime,
263 .read_alarm = at91_rtc_readalarm,
264 .set_alarm = at91_rtc_setalarm,
265 .proc = at91_rtc_proc,
269 * Initialize and install RTC driver
271 static int __init at91_rtc_probe(struct platform_device *pdev)
273 struct rtc_device *rtc;
276 at91_sys_write(AT91_RTC_CR, 0);
277 at91_sys_write(AT91_RTC_MR, 0); /* 24 hour mode */
279 /* Disable all interrupts */
280 at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM | AT91_RTC_SECEV | AT91_RTC_TIMEV | AT91_RTC_CALEV);
282 ret = request_irq(AT91_ID_SYS, at91_rtc_interrupt, SA_SHIRQ, "at91_rtc", pdev);
284 printk(KERN_ERR "at91_rtc: IRQ %d already in use.\n", AT91_ID_SYS);
288 rtc = rtc_device_register(pdev->name, &pdev->dev, &at91_rtc_ops, THIS_MODULE);
290 free_irq(AT91_ID_SYS, pdev);
293 platform_set_drvdata(pdev, rtc);
295 printk(KERN_INFO "AT91 Real Time Clock driver.\n");
300 * Disable and remove the RTC driver
302 static int __devexit at91_rtc_remove(struct platform_device *pdev)
304 struct rtc_device *rtc = platform_get_drvdata(pdev);
306 /* Disable all interrupts */
307 at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM | AT91_RTC_SECEV | AT91_RTC_TIMEV | AT91_RTC_CALEV);
308 free_irq(AT91_ID_SYS, pdev);
310 rtc_device_unregister(rtc);
311 platform_set_drvdata(pdev, NULL);
318 /* AT91RM9200 RTC Power management control */
320 static struct timespec at91_rtc_delta;
322 static int at91_rtc_suspend(struct platform_device *pdev, pm_message_t state)
325 struct timespec time;
329 /* calculate time delta for suspend */
330 at91_rtc_readtime(&pdev->dev, &tm);
331 rtc_tm_to_time(&tm, &time.tv_sec);
332 save_time_delta(&at91_rtc_delta, &time);
334 pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __FUNCTION__,
335 1900 + tm.tm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
340 static int at91_rtc_resume(struct platform_device *pdev)
343 struct timespec time;
347 at91_rtc_readtime(&pdev->dev, &tm);
348 rtc_tm_to_time(&tm, &time.tv_sec);
349 restore_time_delta(&at91_rtc_delta, &time);
351 pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __FUNCTION__,
352 1900 + tm.tm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
357 #define at91_rtc_suspend NULL
358 #define at91_rtc_resume NULL
361 static struct platform_driver at91_rtc_driver = {
362 .probe = at91_rtc_probe,
363 .remove = at91_rtc_remove,
364 .suspend = at91_rtc_suspend,
365 .resume = at91_rtc_resume,
368 .owner = THIS_MODULE,
372 static int __init at91_rtc_init(void)
374 return platform_driver_register(&at91_rtc_driver);
377 static void __exit at91_rtc_exit(void)
379 platform_driver_unregister(&at91_rtc_driver);
383 module_init(at91_rtc_init);
384 module_exit(at91_rtc_exit);
386 MODULE_AUTHOR("Rick Bronson");
387 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
388 MODULE_LICENSE("GPL");