2 * RTC class driver for "CMOS RTC": PCs, ACPI, etc
4 * Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c)
5 * Copyright (C) 2006 David Brownell (convert to new framework)
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
14 * The original "cmos clock" chip was an MC146818 chip, now obsolete.
15 * That defined the register interface now provided by all PCs, some
16 * non-PC systems, and incorporated into ACPI. Modern PC chipsets
17 * integrate an MC146818 clone in their southbridge, and boards use
18 * that instead of discrete clones like the DS12887 or M48T86. There
19 * are also clones that connect using the LPC bus.
21 * That register API is also used directly by various other drivers
22 * (notably for integrated NVRAM), infrastructure (x86 has code to
23 * bypass the RTC framework, directly reading the RTC during boot
24 * and updating minutes/seconds for systems using NTP synch) and
25 * utilities (like userspace 'hwclock', if no /dev node exists).
27 * So **ALL** calls to CMOS_READ and CMOS_WRITE must be done with
28 * interrupts disabled, holding the global rtc_lock, to exclude those
29 * other drivers and utilities on correctly configured systems.
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/init.h>
34 #include <linux/interrupt.h>
35 #include <linux/spinlock.h>
36 #include <linux/platform_device.h>
37 #include <linux/mod_devicetable.h>
38 #include <linux/log2.h>
41 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
42 #include <asm-generic/rtc.h>
45 struct rtc_device *rtc;
48 struct resource *iomem;
50 void (*wake_on)(struct device *);
51 void (*wake_off)(struct device *);
56 /* newer hardware extends the original register set */
62 /* both platform and pnp busses use negative numbers for invalid irqs */
63 #define is_valid_irq(n) ((n) > 0)
65 static const char driver_name[] = "rtc_cmos";
67 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
68 * always mask it against the irq enable bits in RTC_CONTROL. Bit values
69 * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
71 #define RTC_IRQMASK (RTC_PF | RTC_AF | RTC_UF)
73 static inline int is_intr(u8 rtc_intr)
75 if (!(rtc_intr & RTC_IRQF))
77 return rtc_intr & RTC_IRQMASK;
80 /*----------------------------------------------------------------*/
82 /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
83 * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
84 * used in a broken "legacy replacement" mode. The breakage includes
85 * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
88 * When that broken mode is in use, platform glue provides a partial
89 * emulation of hardware RTC IRQ facilities using HPET #1. We don't
90 * want to use HPET for anything except those IRQs though...
92 #ifdef CONFIG_HPET_EMULATE_RTC
96 static inline int is_hpet_enabled(void)
101 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
106 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
112 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
117 static inline int hpet_set_periodic_freq(unsigned long freq)
122 static inline int hpet_rtc_dropped_irq(void)
127 static inline int hpet_rtc_timer_init(void)
132 extern irq_handler_t hpet_rtc_interrupt;
134 static inline int hpet_register_irq_handler(irq_handler_t handler)
139 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
146 /*----------------------------------------------------------------*/
150 /* Most newer x86 systems have two register banks, the first used
151 * for RTC and NVRAM and the second only for NVRAM. Caller must
152 * own rtc_lock ... and we won't worry about access during NMI.
154 #define can_bank2 true
156 static inline unsigned char cmos_read_bank2(unsigned char addr)
158 outb(addr, RTC_PORT(2));
159 return inb(RTC_PORT(3));
162 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
164 outb(addr, RTC_PORT(2));
165 outb(val, RTC_PORT(2));
170 #define can_bank2 false
172 static inline unsigned char cmos_read_bank2(unsigned char addr)
177 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
183 /*----------------------------------------------------------------*/
185 static int cmos_read_time(struct device *dev, struct rtc_time *t)
187 /* REVISIT: if the clock has a "century" register, use
188 * that instead of the heuristic in get_rtc_time().
189 * That'll make Y3K compatility (year > 2070) easy!
195 static int cmos_set_time(struct device *dev, struct rtc_time *t)
197 /* REVISIT: set the "century" register if available
199 * NOTE: this ignores the issue whereby updating the seconds
200 * takes effect exactly 500ms after we write the register.
201 * (Also queueing and other delays before we get this far.)
203 return set_rtc_time(t);
206 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
208 struct cmos_rtc *cmos = dev_get_drvdata(dev);
209 unsigned char rtc_control;
211 if (!is_valid_irq(cmos->irq))
214 /* Basic alarms only support hour, minute, and seconds fields.
215 * Some also support day and month, for alarms up to a year in
218 t->time.tm_mday = -1;
221 spin_lock_irq(&rtc_lock);
222 t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
223 t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
224 t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
226 if (cmos->day_alrm) {
227 /* ignore upper bits on readback per ACPI spec */
228 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
229 if (!t->time.tm_mday)
230 t->time.tm_mday = -1;
232 if (cmos->mon_alrm) {
233 t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
239 rtc_control = CMOS_READ(RTC_CONTROL);
240 spin_unlock_irq(&rtc_lock);
242 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
243 if (((unsigned)t->time.tm_sec) < 0x60)
244 t->time.tm_sec = bcd2bin(t->time.tm_sec);
247 if (((unsigned)t->time.tm_min) < 0x60)
248 t->time.tm_min = bcd2bin(t->time.tm_min);
251 if (((unsigned)t->time.tm_hour) < 0x24)
252 t->time.tm_hour = bcd2bin(t->time.tm_hour);
254 t->time.tm_hour = -1;
256 if (cmos->day_alrm) {
257 if (((unsigned)t->time.tm_mday) <= 0x31)
258 t->time.tm_mday = bcd2bin(t->time.tm_mday);
260 t->time.tm_mday = -1;
262 if (cmos->mon_alrm) {
263 if (((unsigned)t->time.tm_mon) <= 0x12)
264 t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
270 t->time.tm_year = -1;
272 t->enabled = !!(rtc_control & RTC_AIE);
278 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
280 unsigned char rtc_intr;
282 /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
283 * allegedly some older rtcs need that to handle irqs properly
285 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
287 if (is_hpet_enabled())
290 rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
291 if (is_intr(rtc_intr))
292 rtc_update_irq(cmos->rtc, 1, rtc_intr);
295 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
297 unsigned char rtc_control;
299 /* flush any pending IRQ status, notably for update irqs,
300 * before we enable new IRQs
302 rtc_control = CMOS_READ(RTC_CONTROL);
303 cmos_checkintr(cmos, rtc_control);
306 CMOS_WRITE(rtc_control, RTC_CONTROL);
307 hpet_set_rtc_irq_bit(mask);
309 cmos_checkintr(cmos, rtc_control);
312 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
314 unsigned char rtc_control;
316 rtc_control = CMOS_READ(RTC_CONTROL);
317 rtc_control &= ~mask;
318 CMOS_WRITE(rtc_control, RTC_CONTROL);
319 hpet_mask_rtc_irq_bit(mask);
321 cmos_checkintr(cmos, rtc_control);
324 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
326 struct cmos_rtc *cmos = dev_get_drvdata(dev);
327 unsigned char mon, mday, hrs, min, sec, rtc_control;
329 if (!is_valid_irq(cmos->irq))
332 mon = t->time.tm_mon + 1;
333 mday = t->time.tm_mday;
334 hrs = t->time.tm_hour;
335 min = t->time.tm_min;
336 sec = t->time.tm_sec;
338 rtc_control = CMOS_READ(RTC_CONTROL);
339 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
340 /* Writing 0xff means "don't care" or "match all". */
341 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
342 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
343 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
344 min = (min < 60) ? bin2bcd(min) : 0xff;
345 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
348 spin_lock_irq(&rtc_lock);
350 /* next rtc irq must not be from previous alarm setting */
351 cmos_irq_disable(cmos, RTC_AIE);
354 CMOS_WRITE(hrs, RTC_HOURS_ALARM);
355 CMOS_WRITE(min, RTC_MINUTES_ALARM);
356 CMOS_WRITE(sec, RTC_SECONDS_ALARM);
358 /* the system may support an "enhanced" alarm */
359 if (cmos->day_alrm) {
360 CMOS_WRITE(mday, cmos->day_alrm);
362 CMOS_WRITE(mon, cmos->mon_alrm);
365 /* FIXME the HPET alarm glue currently ignores day_alrm
368 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
371 cmos_irq_enable(cmos, RTC_AIE);
373 spin_unlock_irq(&rtc_lock);
378 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
380 struct cmos_rtc *cmos = dev_get_drvdata(dev);
383 if (!is_valid_irq(cmos->irq))
386 spin_lock_irqsave(&rtc_lock, flags);
389 cmos_irq_enable(cmos, RTC_AIE);
391 cmos_irq_disable(cmos, RTC_AIE);
393 spin_unlock_irqrestore(&rtc_lock, flags);
397 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
399 static int cmos_procfs(struct device *dev, struct seq_file *seq)
401 struct cmos_rtc *cmos = dev_get_drvdata(dev);
402 unsigned char rtc_control, valid;
404 spin_lock_irq(&rtc_lock);
405 rtc_control = CMOS_READ(RTC_CONTROL);
406 valid = CMOS_READ(RTC_VALID);
407 spin_unlock_irq(&rtc_lock);
409 /* NOTE: at least ICH6 reports battery status using a different
410 * (non-RTC) bit; and SQWE is ignored on many current systems.
412 return seq_printf(seq,
413 "periodic_IRQ\t: %s\n"
415 "HPET_emulated\t: %s\n"
416 // "square_wave\t: %s\n"
419 "periodic_freq\t: %d\n"
420 "batt_status\t: %s\n",
421 (rtc_control & RTC_PIE) ? "yes" : "no",
422 (rtc_control & RTC_UIE) ? "yes" : "no",
423 is_hpet_enabled() ? "yes" : "no",
424 // (rtc_control & RTC_SQWE) ? "yes" : "no",
425 (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
426 (rtc_control & RTC_DST_EN) ? "yes" : "no",
428 (valid & RTC_VRT) ? "okay" : "dead");
432 #define cmos_procfs NULL
435 static const struct rtc_class_ops cmos_rtc_ops = {
436 .read_time = cmos_read_time,
437 .set_time = cmos_set_time,
438 .read_alarm = cmos_read_alarm,
439 .set_alarm = cmos_set_alarm,
441 .alarm_irq_enable = cmos_alarm_irq_enable,
444 /*----------------------------------------------------------------*/
447 * All these chips have at least 64 bytes of address space, shared by
448 * RTC registers and NVRAM. Most of those bytes of NVRAM are used
449 * by boot firmware. Modern chips have 128 or 256 bytes.
452 #define NVRAM_OFFSET (RTC_REG_D + 1)
455 cmos_nvram_read(struct file *filp, struct kobject *kobj,
456 struct bin_attribute *attr,
457 char *buf, loff_t off, size_t count)
461 if (unlikely(off >= attr->size))
463 if (unlikely(off < 0))
465 if ((off + count) > attr->size)
466 count = attr->size - off;
469 spin_lock_irq(&rtc_lock);
470 for (retval = 0; count; count--, off++, retval++) {
472 *buf++ = CMOS_READ(off);
474 *buf++ = cmos_read_bank2(off);
478 spin_unlock_irq(&rtc_lock);
484 cmos_nvram_write(struct file *filp, struct kobject *kobj,
485 struct bin_attribute *attr,
486 char *buf, loff_t off, size_t count)
488 struct cmos_rtc *cmos;
491 cmos = dev_get_drvdata(container_of(kobj, struct device, kobj));
492 if (unlikely(off >= attr->size))
494 if (unlikely(off < 0))
496 if ((off + count) > attr->size)
497 count = attr->size - off;
499 /* NOTE: on at least PCs and Ataris, the boot firmware uses a
500 * checksum on part of the NVRAM data. That's currently ignored
501 * here. If userspace is smart enough to know what fields of
502 * NVRAM to update, updating checksums is also part of its job.
505 spin_lock_irq(&rtc_lock);
506 for (retval = 0; count; count--, off++, retval++) {
507 /* don't trash RTC registers */
508 if (off == cmos->day_alrm
509 || off == cmos->mon_alrm
510 || off == cmos->century)
513 CMOS_WRITE(*buf++, off);
515 cmos_write_bank2(*buf++, off);
519 spin_unlock_irq(&rtc_lock);
524 static struct bin_attribute nvram = {
527 .mode = S_IRUGO | S_IWUSR,
530 .read = cmos_nvram_read,
531 .write = cmos_nvram_write,
532 /* size gets set up later */
535 /*----------------------------------------------------------------*/
537 static struct cmos_rtc cmos_rtc;
539 static irqreturn_t cmos_interrupt(int irq, void *p)
544 spin_lock(&rtc_lock);
546 /* When the HPET interrupt handler calls us, the interrupt
547 * status is passed as arg1 instead of the irq number. But
548 * always clear irq status, even when HPET is in the way.
550 * Note that HPET and RTC are almost certainly out of phase,
551 * giving different IRQ status ...
553 irqstat = CMOS_READ(RTC_INTR_FLAGS);
554 rtc_control = CMOS_READ(RTC_CONTROL);
555 if (is_hpet_enabled())
556 irqstat = (unsigned long)irq & 0xF0;
557 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
559 /* All Linux RTC alarms should be treated as if they were oneshot.
560 * Similar code may be needed in system wakeup paths, in case the
561 * alarm woke the system.
563 if (irqstat & RTC_AIE) {
564 rtc_control &= ~RTC_AIE;
565 CMOS_WRITE(rtc_control, RTC_CONTROL);
566 hpet_mask_rtc_irq_bit(RTC_AIE);
568 CMOS_READ(RTC_INTR_FLAGS);
570 spin_unlock(&rtc_lock);
572 if (is_intr(irqstat)) {
573 rtc_update_irq(p, 1, irqstat);
583 #define INITSECTION __init
586 static int INITSECTION
587 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
589 struct cmos_rtc_board_info *info = dev->platform_data;
591 unsigned char rtc_control;
592 unsigned address_space;
594 /* there can be only one ... */
601 /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
603 * REVISIT non-x86 systems may instead use memory space resources
604 * (needing ioremap etc), not i/o space resources like this ...
606 ports = request_region(ports->start,
607 ports->end + 1 - ports->start,
610 dev_dbg(dev, "i/o registers already in use\n");
614 cmos_rtc.irq = rtc_irq;
615 cmos_rtc.iomem = ports;
617 /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
618 * driver did, but don't reject unknown configs. Old hardware
619 * won't address 128 bytes. Newer chips have multiple banks,
620 * though they may not be listed in one I/O resource.
622 #if defined(CONFIG_ATARI)
624 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
625 || defined(__sparc__) || defined(__mips__) \
626 || defined(__powerpc__)
629 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
632 if (can_bank2 && ports->end > (ports->start + 1))
635 /* For ACPI systems extension info comes from the FADT. On others,
636 * board specific setup provides it as appropriate. Systems where
637 * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
638 * some almost-clones) can provide hooks to make that behave.
640 * Note that ACPI doesn't preclude putting these registers into
641 * "extended" areas of the chip, including some that we won't yet
642 * expect CMOS_READ and friends to handle.
645 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
646 cmos_rtc.day_alrm = info->rtc_day_alarm;
647 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
648 cmos_rtc.mon_alrm = info->rtc_mon_alarm;
649 if (info->rtc_century && info->rtc_century < 128)
650 cmos_rtc.century = info->rtc_century;
652 if (info->wake_on && info->wake_off) {
653 cmos_rtc.wake_on = info->wake_on;
654 cmos_rtc.wake_off = info->wake_off;
659 dev_set_drvdata(dev, &cmos_rtc);
661 cmos_rtc.rtc = rtc_device_register(driver_name, dev,
662 &cmos_rtc_ops, THIS_MODULE);
663 if (IS_ERR(cmos_rtc.rtc)) {
664 retval = PTR_ERR(cmos_rtc.rtc);
668 rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
670 spin_lock_irq(&rtc_lock);
672 /* force periodic irq to CMOS reset default of 1024Hz;
674 * REVISIT it's been reported that at least one x86_64 ALI mobo
675 * doesn't use 32KHz here ... for portability we might need to
676 * do something about other clock frequencies.
678 cmos_rtc.rtc->irq_freq = 1024;
679 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
680 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
683 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
685 rtc_control = CMOS_READ(RTC_CONTROL);
687 spin_unlock_irq(&rtc_lock);
690 * <asm-generic/rtc.h> doesn't know 12-hour mode either.
692 if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
693 dev_warn(dev, "only 24-hr supported\n");
698 if (is_valid_irq(rtc_irq)) {
699 irq_handler_t rtc_cmos_int_handler;
701 if (is_hpet_enabled()) {
704 rtc_cmos_int_handler = hpet_rtc_interrupt;
705 err = hpet_register_irq_handler(cmos_interrupt);
707 printk(KERN_WARNING "hpet_register_irq_handler "
708 " failed in rtc_init().");
712 rtc_cmos_int_handler = cmos_interrupt;
714 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
715 IRQF_DISABLED, dev_name(&cmos_rtc.rtc->dev),
718 dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
722 hpet_rtc_timer_init();
724 /* export at least the first block of NVRAM */
725 nvram.size = address_space - NVRAM_OFFSET;
726 retval = sysfs_create_bin_file(&dev->kobj, &nvram);
728 dev_dbg(dev, "can't create nvram file? %d\n", retval);
732 pr_info("%s: %s%s, %zd bytes nvram%s\n",
733 dev_name(&cmos_rtc.rtc->dev),
734 !is_valid_irq(rtc_irq) ? "no alarms" :
735 cmos_rtc.mon_alrm ? "alarms up to one year" :
736 cmos_rtc.day_alrm ? "alarms up to one month" :
737 "alarms up to one day",
738 cmos_rtc.century ? ", y3k" : "",
740 is_hpet_enabled() ? ", hpet irqs" : "");
745 if (is_valid_irq(rtc_irq))
746 free_irq(rtc_irq, cmos_rtc.rtc);
749 rtc_device_unregister(cmos_rtc.rtc);
751 release_region(ports->start, ports->end + 1 - ports->start);
755 static void cmos_do_shutdown(void)
757 spin_lock_irq(&rtc_lock);
758 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
759 spin_unlock_irq(&rtc_lock);
762 static void __exit cmos_do_remove(struct device *dev)
764 struct cmos_rtc *cmos = dev_get_drvdata(dev);
765 struct resource *ports;
769 sysfs_remove_bin_file(&dev->kobj, &nvram);
771 if (is_valid_irq(cmos->irq)) {
772 free_irq(cmos->irq, cmos->rtc);
773 hpet_unregister_irq_handler(cmos_interrupt);
776 rtc_device_unregister(cmos->rtc);
780 release_region(ports->start, ports->end + 1 - ports->start);
784 dev_set_drvdata(dev, NULL);
789 static int cmos_suspend(struct device *dev)
791 struct cmos_rtc *cmos = dev_get_drvdata(dev);
794 /* only the alarm might be a wakeup event source */
795 spin_lock_irq(&rtc_lock);
796 cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
797 if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
800 if (device_may_wakeup(dev))
801 mask = RTC_IRQMASK & ~RTC_AIE;
805 CMOS_WRITE(tmp, RTC_CONTROL);
807 /* shut down hpet emulation - we don't need it for alarm */
808 hpet_mask_rtc_irq_bit(RTC_PIE|RTC_AIE|RTC_UIE);
809 cmos_checkintr(cmos, tmp);
811 spin_unlock_irq(&rtc_lock);
814 cmos->enabled_wake = 1;
818 enable_irq_wake(cmos->irq);
821 pr_debug("%s: suspend%s, ctrl %02x\n",
822 dev_name(&cmos_rtc.rtc->dev),
823 (tmp & RTC_AIE) ? ", alarm may wake" : "",
829 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
830 * after a detour through G3 "mechanical off", although the ACPI spec
831 * says wakeup should only work from G1/S4 "hibernate". To most users,
832 * distinctions between S4 and S5 are pointless. So when the hardware
833 * allows, don't draw that distinction.
835 static inline int cmos_poweroff(struct device *dev)
837 return cmos_suspend(dev);
840 static int cmos_resume(struct device *dev)
842 struct cmos_rtc *cmos = dev_get_drvdata(dev);
843 unsigned char tmp = cmos->suspend_ctrl;
845 /* re-enable any irqs previously active */
846 if (tmp & RTC_IRQMASK) {
849 if (cmos->enabled_wake) {
853 disable_irq_wake(cmos->irq);
854 cmos->enabled_wake = 0;
857 spin_lock_irq(&rtc_lock);
859 CMOS_WRITE(tmp, RTC_CONTROL);
860 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
862 mask = CMOS_READ(RTC_INTR_FLAGS);
863 mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
864 if (!is_hpet_enabled() || !is_intr(mask))
867 /* force one-shot behavior if HPET blocked
868 * the wake alarm's irq
870 rtc_update_irq(cmos->rtc, 1, mask);
872 hpet_mask_rtc_irq_bit(RTC_AIE);
873 } while (mask & RTC_AIE);
874 spin_unlock_irq(&rtc_lock);
877 pr_debug("%s: resume, ctrl %02x\n",
878 dev_name(&cmos_rtc.rtc->dev),
884 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
888 static inline int cmos_poweroff(struct device *dev)
895 /*----------------------------------------------------------------*/
897 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
898 * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
899 * probably list them in similar PNPBIOS tables; so PNP is more common.
901 * We don't use legacy "poke at the hardware" probing. Ancient PCs that
902 * predate even PNPBIOS should set up platform_bus devices.
907 #include <linux/acpi.h>
909 static u32 rtc_handler(void *context)
911 acpi_clear_event(ACPI_EVENT_RTC);
912 acpi_disable_event(ACPI_EVENT_RTC, 0);
913 return ACPI_INTERRUPT_HANDLED;
916 static inline void rtc_wake_setup(void)
918 acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, NULL);
920 * After the RTC handler is installed, the Fixed_RTC event should
921 * be disabled. Only when the RTC alarm is set will it be enabled.
923 acpi_clear_event(ACPI_EVENT_RTC);
924 acpi_disable_event(ACPI_EVENT_RTC, 0);
927 static void rtc_wake_on(struct device *dev)
929 acpi_clear_event(ACPI_EVENT_RTC);
930 acpi_enable_event(ACPI_EVENT_RTC, 0);
933 static void rtc_wake_off(struct device *dev)
935 acpi_disable_event(ACPI_EVENT_RTC, 0);
938 /* Every ACPI platform has a mc146818 compatible "cmos rtc". Here we find
939 * its device node and pass extra config data. This helps its driver use
940 * capabilities that the now-obsolete mc146818 didn't have, and informs it
941 * that this board's RTC is wakeup-capable (per ACPI spec).
943 static struct cmos_rtc_board_info acpi_rtc_info;
945 static void __devinit
946 cmos_wake_setup(struct device *dev)
952 acpi_rtc_info.wake_on = rtc_wake_on;
953 acpi_rtc_info.wake_off = rtc_wake_off;
955 /* workaround bug in some ACPI tables */
956 if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
957 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
958 acpi_gbl_FADT.month_alarm);
959 acpi_gbl_FADT.month_alarm = 0;
962 acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
963 acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
964 acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
966 /* NOTE: S4_RTC_WAKE is NOT currently useful to Linux */
967 if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
968 dev_info(dev, "RTC can wake from S4\n");
970 dev->platform_data = &acpi_rtc_info;
972 /* RTC always wakes from S1/S2/S3, and often S4/STD */
973 device_init_wakeup(dev, 1);
978 static void __devinit
979 cmos_wake_setup(struct device *dev)
987 #include <linux/pnp.h>
990 cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
992 cmos_wake_setup(&pnp->dev);
994 if (pnp_port_start(pnp,0) == 0x70 && !pnp_irq_valid(pnp,0))
995 /* Some machines contain a PNP entry for the RTC, but
996 * don't define the IRQ. It should always be safe to
997 * hardcode it in these cases
999 return cmos_do_probe(&pnp->dev,
1000 pnp_get_resource(pnp, IORESOURCE_IO, 0), 8);
1002 return cmos_do_probe(&pnp->dev,
1003 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1007 static void __exit cmos_pnp_remove(struct pnp_dev *pnp)
1009 cmos_do_remove(&pnp->dev);
1014 static int cmos_pnp_suspend(struct pnp_dev *pnp, pm_message_t mesg)
1016 return cmos_suspend(&pnp->dev);
1019 static int cmos_pnp_resume(struct pnp_dev *pnp)
1021 return cmos_resume(&pnp->dev);
1025 #define cmos_pnp_suspend NULL
1026 #define cmos_pnp_resume NULL
1029 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1031 if (system_state == SYSTEM_POWER_OFF && !cmos_poweroff(&pnp->dev))
1037 static const struct pnp_device_id rtc_ids[] = {
1038 { .id = "PNP0b00", },
1039 { .id = "PNP0b01", },
1040 { .id = "PNP0b02", },
1043 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1045 static struct pnp_driver cmos_pnp_driver = {
1046 .name = (char *) driver_name,
1047 .id_table = rtc_ids,
1048 .probe = cmos_pnp_probe,
1049 .remove = __exit_p(cmos_pnp_remove),
1050 .shutdown = cmos_pnp_shutdown,
1052 /* flag ensures resume() gets called, and stops syslog spam */
1053 .flags = PNP_DRIVER_RES_DO_NOT_CHANGE,
1054 .suspend = cmos_pnp_suspend,
1055 .resume = cmos_pnp_resume,
1058 #endif /* CONFIG_PNP */
1060 /*----------------------------------------------------------------*/
1062 /* Platform setup should have set up an RTC device, when PNP is
1063 * unavailable ... this could happen even on (older) PCs.
1066 static int __init cmos_platform_probe(struct platform_device *pdev)
1068 cmos_wake_setup(&pdev->dev);
1069 return cmos_do_probe(&pdev->dev,
1070 platform_get_resource(pdev, IORESOURCE_IO, 0),
1071 platform_get_irq(pdev, 0));
1074 static int __exit cmos_platform_remove(struct platform_device *pdev)
1076 cmos_do_remove(&pdev->dev);
1080 static void cmos_platform_shutdown(struct platform_device *pdev)
1082 if (system_state == SYSTEM_POWER_OFF && !cmos_poweroff(&pdev->dev))
1088 /* work with hotplug and coldplug */
1089 MODULE_ALIAS("platform:rtc_cmos");
1091 static struct platform_driver cmos_platform_driver = {
1092 .remove = __exit_p(cmos_platform_remove),
1093 .shutdown = cmos_platform_shutdown,
1095 .name = (char *) driver_name,
1103 static bool pnp_driver_registered;
1105 static bool platform_driver_registered;
1107 static int __init cmos_init(void)
1112 retval = pnp_register_driver(&cmos_pnp_driver);
1114 pnp_driver_registered = true;
1117 if (!cmos_rtc.dev) {
1118 retval = platform_driver_probe(&cmos_platform_driver,
1119 cmos_platform_probe);
1121 platform_driver_registered = true;
1128 if (pnp_driver_registered)
1129 pnp_unregister_driver(&cmos_pnp_driver);
1133 module_init(cmos_init);
1135 static void __exit cmos_exit(void)
1138 if (pnp_driver_registered)
1139 pnp_unregister_driver(&cmos_pnp_driver);
1141 if (platform_driver_registered)
1142 platform_driver_unregister(&cmos_platform_driver);
1144 module_exit(cmos_exit);
1147 MODULE_AUTHOR("David Brownell");
1148 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1149 MODULE_LICENSE("GPL");