2 * Real Time Clock interface for StrongARM SA1x00 and XScale PXA2xx
4 * Copyright (c) 2000 Nils Faerber
6 * Based on rtc.c by Paul Gortmaker
8 * Original Driver by Nils Faerber <nils@kernelconcepts.de>
11 * CIH <cih@coventive.com>
12 * Nicolas Pitre <nico@fluxnic.net>
13 * Andrew Christian <andrew.christian@hp.com>
15 * Converted to the RTC subsystem and Driver Model
16 * by Richard Purdie <rpurdie@rpsys.net>
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
24 #include <linux/platform_device.h>
25 #include <linux/module.h>
26 #include <linux/rtc.h>
27 #include <linux/init.h>
29 #include <linux/interrupt.h>
30 #include <linux/string.h>
32 #include <linux/bitops.h>
34 #include <mach/hardware.h>
37 #ifdef CONFIG_ARCH_PXA
38 #include <mach/regs-rtc.h>
39 #include <mach/regs-ost.h>
42 #define RTC_DEF_DIVIDER (32768 - 1)
43 #define RTC_DEF_TRIM 0
45 static const unsigned long RTC_FREQ = 1024;
46 static struct rtc_time rtc_alarm;
47 static DEFINE_SPINLOCK(sa1100_rtc_lock);
49 static inline int rtc_periodic_alarm(struct rtc_time *tm)
51 return (tm->tm_year == -1) ||
52 ((unsigned)tm->tm_mon >= 12) ||
53 ((unsigned)(tm->tm_mday - 1) >= 31) ||
54 ((unsigned)tm->tm_hour > 23) ||
55 ((unsigned)tm->tm_min > 59) ||
56 ((unsigned)tm->tm_sec > 59);
60 * Calculate the next alarm time given the requested alarm time mask
61 * and the current time.
63 static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now,
64 struct rtc_time *alrm)
66 unsigned long next_time;
67 unsigned long now_time;
69 next->tm_year = now->tm_year;
70 next->tm_mon = now->tm_mon;
71 next->tm_mday = now->tm_mday;
72 next->tm_hour = alrm->tm_hour;
73 next->tm_min = alrm->tm_min;
74 next->tm_sec = alrm->tm_sec;
76 rtc_tm_to_time(now, &now_time);
77 rtc_tm_to_time(next, &next_time);
79 if (next_time < now_time) {
81 next_time += 60 * 60 * 24;
82 rtc_time_to_tm(next_time, next);
86 static int rtc_update_alarm(struct rtc_time *alrm)
88 struct rtc_time alarm_tm, now_tm;
89 unsigned long now, time;
94 rtc_time_to_tm(now, &now_tm);
95 rtc_next_alarm_time(&alarm_tm, &now_tm, alrm);
96 ret = rtc_tm_to_time(&alarm_tm, &time);
100 RTSR = RTSR & (RTSR_HZE|RTSR_ALE|RTSR_AL);
102 } while (now != RCNR);
107 static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id)
109 struct platform_device *pdev = to_platform_device(dev_id);
110 struct rtc_device *rtc = platform_get_drvdata(pdev);
112 unsigned long events = 0;
114 spin_lock(&sa1100_rtc_lock);
117 /* clear interrupt sources */
119 /* Fix for a nasty initialization problem the in SA11xx RTSR register.
120 * See also the comments in sa1100_rtc_probe(). */
121 if (rtsr & (RTSR_ALE | RTSR_HZE)) {
122 /* This is the original code, before there was the if test
123 * above. This code does not clear interrupts that were not
125 RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2);
127 /* For some reason, it is possible to enter this routine
128 * without interruptions enabled, it has been tested with
129 * several units (Bug in SA11xx chip?).
131 * This situation leads to an infinite "loop" of interrupt
132 * routine calling and as a result the processor seems to
133 * lock on its first call to open(). */
134 RTSR = RTSR_AL | RTSR_HZ;
137 /* clear alarm interrupt if it has occurred */
140 RTSR = rtsr & (RTSR_ALE | RTSR_HZE);
142 /* update irq data & counter */
144 events |= RTC_AF | RTC_IRQF;
146 events |= RTC_UF | RTC_IRQF;
148 rtc_update_irq(rtc, 1, events);
150 if (rtsr & RTSR_AL && rtc_periodic_alarm(&rtc_alarm))
151 rtc_update_alarm(&rtc_alarm);
153 spin_unlock(&sa1100_rtc_lock);
158 static int sa1100_rtc_open(struct device *dev)
161 struct platform_device *plat_dev = to_platform_device(dev);
162 struct rtc_device *rtc = platform_get_drvdata(plat_dev);
164 ret = request_irq(IRQ_RTC1Hz, sa1100_rtc_interrupt, IRQF_DISABLED,
167 dev_err(dev, "IRQ %d already in use.\n", IRQ_RTC1Hz);
170 ret = request_irq(IRQ_RTCAlrm, sa1100_rtc_interrupt, IRQF_DISABLED,
173 dev_err(dev, "IRQ %d already in use.\n", IRQ_RTCAlrm);
176 rtc->max_user_freq = RTC_FREQ;
177 rtc_irq_set_freq(rtc, NULL, RTC_FREQ);
182 free_irq(IRQ_RTC1Hz, dev);
187 static void sa1100_rtc_release(struct device *dev)
189 spin_lock_irq(&sa1100_rtc_lock);
193 spin_unlock_irq(&sa1100_rtc_lock);
195 free_irq(IRQ_RTCAlrm, dev);
196 free_irq(IRQ_RTC1Hz, dev);
199 static int sa1100_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
201 spin_lock_irq(&sa1100_rtc_lock);
206 spin_unlock_irq(&sa1100_rtc_lock);
210 static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm)
212 rtc_time_to_tm(RCNR, tm);
216 static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm)
221 ret = rtc_tm_to_time(tm, &time);
227 static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
231 memcpy(&alrm->time, &rtc_alarm, sizeof(struct rtc_time));
233 alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0;
234 alrm->pending = (rtsr & RTSR_AL) ? 1 : 0;
238 static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
242 spin_lock_irq(&sa1100_rtc_lock);
243 ret = rtc_update_alarm(&alrm->time);
250 spin_unlock_irq(&sa1100_rtc_lock);
255 static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq)
257 seq_printf(seq, "trim/divider\t\t: 0x%08x\n", (u32) RTTR);
258 seq_printf(seq, "RTSR\t\t\t: 0x%08x\n", (u32)RTSR);
263 static const struct rtc_class_ops sa1100_rtc_ops = {
264 .open = sa1100_rtc_open,
265 .release = sa1100_rtc_release,
266 .read_time = sa1100_rtc_read_time,
267 .set_time = sa1100_rtc_set_time,
268 .read_alarm = sa1100_rtc_read_alarm,
269 .set_alarm = sa1100_rtc_set_alarm,
270 .proc = sa1100_rtc_proc,
271 .alarm_irq_enable = sa1100_rtc_alarm_irq_enable,
274 static int sa1100_rtc_probe(struct platform_device *pdev)
276 struct rtc_device *rtc;
279 * According to the manual we should be able to let RTTR be zero
280 * and then a default diviser for a 32.768KHz clock is used.
281 * Apparently this doesn't work, at least for my SA1110 rev 5.
282 * If the clock divider is uninitialized then reset it to the
283 * default value to get the 1Hz clock.
286 RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16);
287 dev_warn(&pdev->dev, "warning: "
288 "initializing default clock divider/trim value\n");
289 /* The current RTC value probably doesn't make sense either */
293 device_init_wakeup(&pdev->dev, 1);
295 rtc = rtc_device_register(pdev->name, &pdev->dev, &sa1100_rtc_ops,
301 platform_set_drvdata(pdev, rtc);
303 /* Fix for a nasty initialization problem the in SA11xx RTSR register.
304 * See also the comments in sa1100_rtc_interrupt().
306 * Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an
307 * interrupt pending, even though interrupts were never enabled.
308 * In this case, this bit it must be reset before enabling
309 * interruptions to avoid a nonexistent interrupt to occur.
311 * In principle, the same problem would apply to bit 0, although it has
312 * never been observed to happen.
314 * This issue is addressed both here and in sa1100_rtc_interrupt().
315 * If the issue is not addressed here, in the times when the processor
316 * wakes up with the bit set there will be one spurious interrupt.
318 * The issue is also dealt with in sa1100_rtc_interrupt() to be on the
319 * safe side, once the condition that lead to this strange
320 * initialization is unknown and could in principle happen during
323 * Notice that clearing bit 1 and 0 is accomplished by writting ONES to
324 * the corresponding bits in RTSR. */
325 RTSR = RTSR_AL | RTSR_HZ;
330 static int sa1100_rtc_remove(struct platform_device *pdev)
332 struct rtc_device *rtc = platform_get_drvdata(pdev);
335 rtc_device_unregister(rtc);
341 static int sa1100_rtc_suspend(struct device *dev)
343 if (device_may_wakeup(dev))
344 enable_irq_wake(IRQ_RTCAlrm);
348 static int sa1100_rtc_resume(struct device *dev)
350 if (device_may_wakeup(dev))
351 disable_irq_wake(IRQ_RTCAlrm);
355 static const struct dev_pm_ops sa1100_rtc_pm_ops = {
356 .suspend = sa1100_rtc_suspend,
357 .resume = sa1100_rtc_resume,
361 static struct platform_driver sa1100_rtc_driver = {
362 .probe = sa1100_rtc_probe,
363 .remove = sa1100_rtc_remove,
365 .name = "sa1100-rtc",
367 .pm = &sa1100_rtc_pm_ops,
372 static int __init sa1100_rtc_init(void)
374 return platform_driver_register(&sa1100_rtc_driver);
377 static void __exit sa1100_rtc_exit(void)
379 platform_driver_unregister(&sa1100_rtc_driver);
382 module_init(sa1100_rtc_init);
383 module_exit(sa1100_rtc_exit);
385 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
386 MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)");
387 MODULE_LICENSE("GPL");
388 MODULE_ALIAS("platform:sa1100-rtc");