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 unsigned long timer_freq
;
47 static struct rtc_time rtc_alarm
;
48 static DEFINE_SPINLOCK(sa1100_rtc_lock
);
50 static inline int rtc_periodic_alarm(struct rtc_time
*tm
)
52 return (tm
->tm_year
== -1) ||
53 ((unsigned)tm
->tm_mon
>= 12) ||
54 ((unsigned)(tm
->tm_mday
- 1) >= 31) ||
55 ((unsigned)tm
->tm_hour
> 23) ||
56 ((unsigned)tm
->tm_min
> 59) ||
57 ((unsigned)tm
->tm_sec
> 59);
61 * Calculate the next alarm time given the requested alarm time mask
62 * and the current time.
64 static void rtc_next_alarm_time(struct rtc_time
*next
, struct rtc_time
*now
,
65 struct rtc_time
*alrm
)
67 unsigned long next_time
;
68 unsigned long now_time
;
70 next
->tm_year
= now
->tm_year
;
71 next
->tm_mon
= now
->tm_mon
;
72 next
->tm_mday
= now
->tm_mday
;
73 next
->tm_hour
= alrm
->tm_hour
;
74 next
->tm_min
= alrm
->tm_min
;
75 next
->tm_sec
= alrm
->tm_sec
;
77 rtc_tm_to_time(now
, &now_time
);
78 rtc_tm_to_time(next
, &next_time
);
80 if (next_time
< now_time
) {
82 next_time
+= 60 * 60 * 24;
83 rtc_time_to_tm(next_time
, next
);
87 static int rtc_update_alarm(struct rtc_time
*alrm
)
89 struct rtc_time alarm_tm
, now_tm
;
90 unsigned long now
, time
;
95 rtc_time_to_tm(now
, &now_tm
);
96 rtc_next_alarm_time(&alarm_tm
, &now_tm
, alrm
);
97 ret
= rtc_tm_to_time(&alarm_tm
, &time
);
101 RTSR
= RTSR
& (RTSR_HZE
|RTSR_ALE
|RTSR_AL
);
103 } while (now
!= RCNR
);
108 static irqreturn_t
sa1100_rtc_interrupt(int irq
, void *dev_id
)
110 struct platform_device
*pdev
= to_platform_device(dev_id
);
111 struct rtc_device
*rtc
= platform_get_drvdata(pdev
);
113 unsigned long events
= 0;
115 spin_lock(&sa1100_rtc_lock
);
118 /* clear interrupt sources */
120 /* Fix for a nasty initialization problem the in SA11xx RTSR register.
121 * See also the comments in sa1100_rtc_probe(). */
122 if (rtsr
& (RTSR_ALE
| RTSR_HZE
)) {
123 /* This is the original code, before there was the if test
124 * above. This code does not clear interrupts that were not
126 RTSR
= (RTSR_AL
| RTSR_HZ
) & (rtsr
>> 2);
128 /* For some reason, it is possible to enter this routine
129 * without interruptions enabled, it has been tested with
130 * several units (Bug in SA11xx chip?).
132 * This situation leads to an infinite "loop" of interrupt
133 * routine calling and as a result the processor seems to
134 * lock on its first call to open(). */
135 RTSR
= RTSR_AL
| RTSR_HZ
;
138 /* clear alarm interrupt if it has occurred */
141 RTSR
= rtsr
& (RTSR_ALE
| RTSR_HZE
);
143 /* update irq data & counter */
145 events
|= RTC_AF
| RTC_IRQF
;
147 events
|= RTC_UF
| RTC_IRQF
;
149 rtc_update_irq(rtc
, 1, events
);
151 if (rtsr
& RTSR_AL
&& rtc_periodic_alarm(&rtc_alarm
))
152 rtc_update_alarm(&rtc_alarm
);
154 spin_unlock(&sa1100_rtc_lock
);
159 static int sa1100_irq_set_freq(struct device
*dev
, int freq
)
161 if (freq
< 1 || freq
> timer_freq
) {
164 struct rtc_device
*rtc
= (struct rtc_device
*)dev
;
166 rtc
->irq_freq
= freq
;
172 static int rtc_timer1_count
;
174 static int sa1100_irq_set_state(struct device
*dev
, int enabled
)
176 spin_lock_irq(&sa1100_rtc_lock
);
178 struct rtc_device
*rtc
= (struct rtc_device
*)dev
;
180 OSMR1
= timer_freq
/ rtc
->irq_freq
+ OSCR
;
182 rtc_timer1_count
= 1;
186 spin_unlock_irq(&sa1100_rtc_lock
);
191 static inline int sa1100_timer1_retrigger(struct rtc_device
*rtc
)
194 unsigned long period
= timer_freq
/ rtc
->irq_freq
;
196 spin_lock_irq(&sa1100_rtc_lock
);
201 /* If OSCR > OSMR1, diff is a very large number (unsigned
202 * math). This means we have a lost interrupt. */
203 } while (diff
> period
);
206 spin_unlock_irq(&sa1100_rtc_lock
);
211 static irqreturn_t
timer1_interrupt(int irq
, void *dev_id
)
213 struct platform_device
*pdev
= to_platform_device(dev_id
);
214 struct rtc_device
*rtc
= platform_get_drvdata(pdev
);
217 * If we match for the first time, rtc_timer1_count will be 1.
218 * Otherwise, we wrapped around (very unlikely but
219 * still possible) so compute the amount of missed periods.
220 * The match reg is updated only when the data is actually retrieved
221 * to avoid unnecessary interrupts.
223 OSSR
= OSSR_M1
; /* clear match on timer1 */
225 rtc_update_irq(rtc
, rtc_timer1_count
, RTC_PF
| RTC_IRQF
);
227 if (rtc_timer1_count
== 1)
229 (rtc
->irq_freq
* ((1 << 30) / (timer_freq
>> 2)));
232 sa1100_timer1_retrigger(rtc
);
237 static int sa1100_rtc_read_callback(struct device
*dev
, int data
)
240 struct rtc_device
*rtc
= (struct rtc_device
*)dev
;
242 /* interpolate missed periods and set match for the next */
243 unsigned long period
= timer_freq
/ rtc
->irq_freq
;
244 unsigned long oscr
= OSCR
;
245 unsigned long osmr1
= OSMR1
;
246 unsigned long missed
= (oscr
- osmr1
)/period
;
248 OSSR
= OSSR_M1
; /* clear match on timer 1 */
249 OSMR1
= osmr1
+ (missed
+ 1)*period
;
250 /* Ensure we didn't miss another match in the mean time.
251 * Here we compare (match - OSCR) 8 instead of 0 --
252 * see comment in pxa_timer_interrupt() for explanation.
254 while ((signed long)((osmr1
= OSMR1
) - OSCR
) <= 8) {
256 OSSR
= OSSR_M1
; /* clear match on timer 1 */
257 OSMR1
= osmr1
+ period
;
263 static int sa1100_rtc_open(struct device
*dev
)
266 struct rtc_device
*rtc
= (struct rtc_device
*)dev
;
268 ret
= request_irq(IRQ_RTC1Hz
, sa1100_rtc_interrupt
, IRQF_DISABLED
,
271 dev_err(dev
, "IRQ %d already in use.\n", IRQ_RTC1Hz
);
274 ret
= request_irq(IRQ_RTCAlrm
, sa1100_rtc_interrupt
, IRQF_DISABLED
,
277 dev_err(dev
, "IRQ %d already in use.\n", IRQ_RTCAlrm
);
280 ret
= request_irq(IRQ_OST1
, timer1_interrupt
, IRQF_DISABLED
,
283 dev_err(dev
, "IRQ %d already in use.\n", IRQ_OST1
);
286 rtc
->max_user_freq
= RTC_FREQ
;
287 sa1100_irq_set_freq(dev
, RTC_FREQ
);
292 free_irq(IRQ_RTCAlrm
, dev
);
294 free_irq(IRQ_RTC1Hz
, dev
);
299 static void sa1100_rtc_release(struct device
*dev
)
301 spin_lock_irq(&sa1100_rtc_lock
);
305 spin_unlock_irq(&sa1100_rtc_lock
);
307 free_irq(IRQ_OST1
, dev
);
308 free_irq(IRQ_RTCAlrm
, dev
);
309 free_irq(IRQ_RTC1Hz
, dev
);
313 static int sa1100_rtc_ioctl(struct device
*dev
, unsigned int cmd
,
318 spin_lock_irq(&sa1100_rtc_lock
);
320 spin_unlock_irq(&sa1100_rtc_lock
);
323 spin_lock_irq(&sa1100_rtc_lock
);
325 spin_unlock_irq(&sa1100_rtc_lock
);
328 spin_lock_irq(&sa1100_rtc_lock
);
330 spin_unlock_irq(&sa1100_rtc_lock
);
333 spin_lock_irq(&sa1100_rtc_lock
);
335 spin_unlock_irq(&sa1100_rtc_lock
);
341 static int sa1100_rtc_read_time(struct device
*dev
, struct rtc_time
*tm
)
343 rtc_time_to_tm(RCNR
, tm
);
347 static int sa1100_rtc_set_time(struct device
*dev
, struct rtc_time
*tm
)
352 ret
= rtc_tm_to_time(tm
, &time
);
358 static int sa1100_rtc_read_alarm(struct device
*dev
, struct rtc_wkalrm
*alrm
)
362 memcpy(&alrm
->time
, &rtc_alarm
, sizeof(struct rtc_time
));
364 alrm
->enabled
= (rtsr
& RTSR_ALE
) ? 1 : 0;
365 alrm
->pending
= (rtsr
& RTSR_AL
) ? 1 : 0;
369 static int sa1100_rtc_set_alarm(struct device
*dev
, struct rtc_wkalrm
*alrm
)
373 spin_lock_irq(&sa1100_rtc_lock
);
374 ret
= rtc_update_alarm(&alrm
->time
);
381 spin_unlock_irq(&sa1100_rtc_lock
);
386 static int sa1100_rtc_proc(struct device
*dev
, struct seq_file
*seq
)
388 struct rtc_device
*rtc
= (struct rtc_device
*)dev
;
390 seq_printf(seq
, "trim/divider\t: 0x%08x\n", (u32
) RTTR
);
391 seq_printf(seq
, "update_IRQ\t: %s\n",
392 (RTSR
& RTSR_HZE
) ? "yes" : "no");
393 seq_printf(seq
, "periodic_IRQ\t: %s\n",
394 (OIER
& OIER_E1
) ? "yes" : "no");
395 seq_printf(seq
, "periodic_freq\t: %d\n", rtc
->irq_freq
);
396 seq_printf(seq
, "RTSR\t\t: 0x%08x\n", (u32
)RTSR
);
401 static const struct rtc_class_ops sa1100_rtc_ops
= {
402 .open
= sa1100_rtc_open
,
403 .read_callback
= sa1100_rtc_read_callback
,
404 .release
= sa1100_rtc_release
,
405 .ioctl
= sa1100_rtc_ioctl
,
406 .read_time
= sa1100_rtc_read_time
,
407 .set_time
= sa1100_rtc_set_time
,
408 .read_alarm
= sa1100_rtc_read_alarm
,
409 .set_alarm
= sa1100_rtc_set_alarm
,
410 .proc
= sa1100_rtc_proc
,
411 .irq_set_freq
= sa1100_irq_set_freq
,
412 .irq_set_state
= sa1100_irq_set_state
,
415 static int sa1100_rtc_probe(struct platform_device
*pdev
)
417 struct rtc_device
*rtc
;
419 timer_freq
= get_clock_tick_rate();
422 * According to the manual we should be able to let RTTR be zero
423 * and then a default diviser for a 32.768KHz clock is used.
424 * Apparently this doesn't work, at least for my SA1110 rev 5.
425 * If the clock divider is uninitialized then reset it to the
426 * default value to get the 1Hz clock.
429 RTTR
= RTC_DEF_DIVIDER
+ (RTC_DEF_TRIM
<< 16);
430 dev_warn(&pdev
->dev
, "warning: "
431 "initializing default clock divider/trim value\n");
432 /* The current RTC value probably doesn't make sense either */
436 device_init_wakeup(&pdev
->dev
, 1);
438 rtc
= rtc_device_register(pdev
->name
, &pdev
->dev
, &sa1100_rtc_ops
,
444 platform_set_drvdata(pdev
, rtc
);
446 /* Set the irq_freq */
447 /*TODO: Find out who is messing with this value after we initialize
449 rtc
->irq_freq
= RTC_FREQ
;
451 /* Fix for a nasty initialization problem the in SA11xx RTSR register.
452 * See also the comments in sa1100_rtc_interrupt().
454 * Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an
455 * interrupt pending, even though interrupts were never enabled.
456 * In this case, this bit it must be reset before enabling
457 * interruptions to avoid a nonexistent interrupt to occur.
459 * In principle, the same problem would apply to bit 0, although it has
460 * never been observed to happen.
462 * This issue is addressed both here and in sa1100_rtc_interrupt().
463 * If the issue is not addressed here, in the times when the processor
464 * wakes up with the bit set there will be one spurious interrupt.
466 * The issue is also dealt with in sa1100_rtc_interrupt() to be on the
467 * safe side, once the condition that lead to this strange
468 * initialization is unknown and could in principle happen during
471 * Notice that clearing bit 1 and 0 is accomplished by writting ONES to
472 * the corresponding bits in RTSR. */
473 RTSR
= RTSR_AL
| RTSR_HZ
;
478 static int sa1100_rtc_remove(struct platform_device
*pdev
)
480 struct rtc_device
*rtc
= platform_get_drvdata(pdev
);
483 rtc_device_unregister(rtc
);
489 static int sa1100_rtc_suspend(struct device
*dev
)
491 if (device_may_wakeup(dev
))
492 enable_irq_wake(IRQ_RTCAlrm
);
496 static int sa1100_rtc_resume(struct device
*dev
)
498 if (device_may_wakeup(dev
))
499 disable_irq_wake(IRQ_RTCAlrm
);
503 static const struct dev_pm_ops sa1100_rtc_pm_ops
= {
504 .suspend
= sa1100_rtc_suspend
,
505 .resume
= sa1100_rtc_resume
,
509 static struct platform_driver sa1100_rtc_driver
= {
510 .probe
= sa1100_rtc_probe
,
511 .remove
= sa1100_rtc_remove
,
513 .name
= "sa1100-rtc",
515 .pm
= &sa1100_rtc_pm_ops
,
520 static int __init
sa1100_rtc_init(void)
522 return platform_driver_register(&sa1100_rtc_driver
);
525 static void __exit
sa1100_rtc_exit(void)
527 platform_driver_unregister(&sa1100_rtc_driver
);
530 module_init(sa1100_rtc_init
);
531 module_exit(sa1100_rtc_exit
);
533 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
534 MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)");
535 MODULE_LICENSE("GPL");
536 MODULE_ALIAS("platform:sa1100-rtc");