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.
32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34 #include <linux/kernel.h>
35 #include <linux/module.h>
36 #include <linux/init.h>
37 #include <linux/interrupt.h>
38 #include <linux/spinlock.h>
39 #include <linux/platform_device.h>
40 #include <linux/log2.h>
43 #include <linux/of_platform.h>
45 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
46 #include <linux/mc146818rtc.h>
49 struct rtc_device *rtc;
52 struct resource *iomem;
53 time64_t alarm_expires;
55 void (*wake_on)(struct device *);
56 void (*wake_off)(struct device *);
61 /* newer hardware extends the original register set */
67 /* both platform and pnp busses use negative numbers for invalid irqs */
68 #define is_valid_irq(n) ((n) > 0)
70 static const char driver_name[] = "rtc_cmos";
72 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
73 * always mask it against the irq enable bits in RTC_CONTROL. Bit values
74 * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
76 #define RTC_IRQMASK (RTC_PF | RTC_AF | RTC_UF)
78 static inline int is_intr(u8 rtc_intr)
80 if (!(rtc_intr & RTC_IRQF))
82 return rtc_intr & RTC_IRQMASK;
85 /*----------------------------------------------------------------*/
87 /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
88 * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
89 * used in a broken "legacy replacement" mode. The breakage includes
90 * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
93 * When that broken mode is in use, platform glue provides a partial
94 * emulation of hardware RTC IRQ facilities using HPET #1. We don't
95 * want to use HPET for anything except those IRQs though...
97 #ifdef CONFIG_HPET_EMULATE_RTC
101 static inline int is_hpet_enabled(void)
106 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
111 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
117 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
122 static inline int hpet_set_periodic_freq(unsigned long freq)
127 static inline int hpet_rtc_dropped_irq(void)
132 static inline int hpet_rtc_timer_init(void)
137 extern irq_handler_t hpet_rtc_interrupt;
139 static inline int hpet_register_irq_handler(irq_handler_t handler)
144 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
151 /*----------------------------------------------------------------*/
155 /* Most newer x86 systems have two register banks, the first used
156 * for RTC and NVRAM and the second only for NVRAM. Caller must
157 * own rtc_lock ... and we won't worry about access during NMI.
159 #define can_bank2 true
161 static inline unsigned char cmos_read_bank2(unsigned char addr)
163 outb(addr, RTC_PORT(2));
164 return inb(RTC_PORT(3));
167 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
169 outb(addr, RTC_PORT(2));
170 outb(val, RTC_PORT(3));
175 #define can_bank2 false
177 static inline unsigned char cmos_read_bank2(unsigned char addr)
182 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
188 /*----------------------------------------------------------------*/
190 static int cmos_read_time(struct device *dev, struct rtc_time *t)
192 /* REVISIT: if the clock has a "century" register, use
193 * that instead of the heuristic in mc146818_get_time().
194 * That'll make Y3K compatility (year > 2070) easy!
196 mc146818_get_time(t);
200 static int cmos_set_time(struct device *dev, struct rtc_time *t)
202 /* REVISIT: set the "century" register if available
204 * NOTE: this ignores the issue whereby updating the seconds
205 * takes effect exactly 500ms after we write the register.
206 * (Also queueing and other delays before we get this far.)
208 return mc146818_set_time(t);
211 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
213 struct cmos_rtc *cmos = dev_get_drvdata(dev);
214 unsigned char rtc_control;
216 if (!is_valid_irq(cmos->irq))
219 /* Basic alarms only support hour, minute, and seconds fields.
220 * Some also support day and month, for alarms up to a year in
224 spin_lock_irq(&rtc_lock);
225 t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
226 t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
227 t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
229 if (cmos->day_alrm) {
230 /* ignore upper bits on readback per ACPI spec */
231 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
232 if (!t->time.tm_mday)
233 t->time.tm_mday = -1;
235 if (cmos->mon_alrm) {
236 t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
242 rtc_control = CMOS_READ(RTC_CONTROL);
243 spin_unlock_irq(&rtc_lock);
245 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
246 if (((unsigned)t->time.tm_sec) < 0x60)
247 t->time.tm_sec = bcd2bin(t->time.tm_sec);
250 if (((unsigned)t->time.tm_min) < 0x60)
251 t->time.tm_min = bcd2bin(t->time.tm_min);
254 if (((unsigned)t->time.tm_hour) < 0x24)
255 t->time.tm_hour = bcd2bin(t->time.tm_hour);
257 t->time.tm_hour = -1;
259 if (cmos->day_alrm) {
260 if (((unsigned)t->time.tm_mday) <= 0x31)
261 t->time.tm_mday = bcd2bin(t->time.tm_mday);
263 t->time.tm_mday = -1;
265 if (cmos->mon_alrm) {
266 if (((unsigned)t->time.tm_mon) <= 0x12)
267 t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
274 t->enabled = !!(rtc_control & RTC_AIE);
280 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
282 unsigned char rtc_intr;
284 /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
285 * allegedly some older rtcs need that to handle irqs properly
287 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
289 if (is_hpet_enabled())
292 rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
293 if (is_intr(rtc_intr))
294 rtc_update_irq(cmos->rtc, 1, rtc_intr);
297 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
299 unsigned char rtc_control;
301 /* flush any pending IRQ status, notably for update irqs,
302 * before we enable new IRQs
304 rtc_control = CMOS_READ(RTC_CONTROL);
305 cmos_checkintr(cmos, rtc_control);
308 CMOS_WRITE(rtc_control, RTC_CONTROL);
309 hpet_set_rtc_irq_bit(mask);
311 cmos_checkintr(cmos, rtc_control);
314 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
316 unsigned char rtc_control;
318 rtc_control = CMOS_READ(RTC_CONTROL);
319 rtc_control &= ~mask;
320 CMOS_WRITE(rtc_control, RTC_CONTROL);
321 hpet_mask_rtc_irq_bit(mask);
323 cmos_checkintr(cmos, rtc_control);
326 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
328 struct cmos_rtc *cmos = dev_get_drvdata(dev);
329 unsigned char mon, mday, hrs, min, sec, rtc_control;
331 if (!is_valid_irq(cmos->irq))
334 mon = t->time.tm_mon + 1;
335 mday = t->time.tm_mday;
336 hrs = t->time.tm_hour;
337 min = t->time.tm_min;
338 sec = t->time.tm_sec;
340 rtc_control = CMOS_READ(RTC_CONTROL);
341 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
342 /* Writing 0xff means "don't care" or "match all". */
343 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
344 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
345 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
346 min = (min < 60) ? bin2bcd(min) : 0xff;
347 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
350 spin_lock_irq(&rtc_lock);
352 /* next rtc irq must not be from previous alarm setting */
353 cmos_irq_disable(cmos, RTC_AIE);
356 CMOS_WRITE(hrs, RTC_HOURS_ALARM);
357 CMOS_WRITE(min, RTC_MINUTES_ALARM);
358 CMOS_WRITE(sec, RTC_SECONDS_ALARM);
360 /* the system may support an "enhanced" alarm */
361 if (cmos->day_alrm) {
362 CMOS_WRITE(mday, cmos->day_alrm);
364 CMOS_WRITE(mon, cmos->mon_alrm);
367 /* FIXME the HPET alarm glue currently ignores day_alrm
370 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
373 cmos_irq_enable(cmos, RTC_AIE);
375 spin_unlock_irq(&rtc_lock);
377 cmos->alarm_expires = rtc_tm_to_time64(&t->time);
382 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
384 struct cmos_rtc *cmos = dev_get_drvdata(dev);
387 if (!is_valid_irq(cmos->irq))
390 spin_lock_irqsave(&rtc_lock, flags);
393 cmos_irq_enable(cmos, RTC_AIE);
395 cmos_irq_disable(cmos, RTC_AIE);
397 spin_unlock_irqrestore(&rtc_lock, flags);
401 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
403 static int cmos_procfs(struct device *dev, struct seq_file *seq)
405 struct cmos_rtc *cmos = dev_get_drvdata(dev);
406 unsigned char rtc_control, valid;
408 spin_lock_irq(&rtc_lock);
409 rtc_control = CMOS_READ(RTC_CONTROL);
410 valid = CMOS_READ(RTC_VALID);
411 spin_unlock_irq(&rtc_lock);
413 /* NOTE: at least ICH6 reports battery status using a different
414 * (non-RTC) bit; and SQWE is ignored on many current systems.
417 "periodic_IRQ\t: %s\n"
419 "HPET_emulated\t: %s\n"
420 // "square_wave\t: %s\n"
423 "periodic_freq\t: %d\n"
424 "batt_status\t: %s\n",
425 (rtc_control & RTC_PIE) ? "yes" : "no",
426 (rtc_control & RTC_UIE) ? "yes" : "no",
427 is_hpet_enabled() ? "yes" : "no",
428 // (rtc_control & RTC_SQWE) ? "yes" : "no",
429 (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
430 (rtc_control & RTC_DST_EN) ? "yes" : "no",
432 (valid & RTC_VRT) ? "okay" : "dead");
438 #define cmos_procfs NULL
441 static const struct rtc_class_ops cmos_rtc_ops = {
442 .read_time = cmos_read_time,
443 .set_time = cmos_set_time,
444 .read_alarm = cmos_read_alarm,
445 .set_alarm = cmos_set_alarm,
447 .alarm_irq_enable = cmos_alarm_irq_enable,
450 /*----------------------------------------------------------------*/
453 * All these chips have at least 64 bytes of address space, shared by
454 * RTC registers and NVRAM. Most of those bytes of NVRAM are used
455 * by boot firmware. Modern chips have 128 or 256 bytes.
458 #define NVRAM_OFFSET (RTC_REG_D + 1)
461 cmos_nvram_read(struct file *filp, struct kobject *kobj,
462 struct bin_attribute *attr,
463 char *buf, loff_t off, size_t count)
468 spin_lock_irq(&rtc_lock);
469 for (retval = 0; count; count--, off++, retval++) {
471 *buf++ = CMOS_READ(off);
473 *buf++ = cmos_read_bank2(off);
477 spin_unlock_irq(&rtc_lock);
483 cmos_nvram_write(struct file *filp, struct kobject *kobj,
484 struct bin_attribute *attr,
485 char *buf, loff_t off, size_t count)
487 struct cmos_rtc *cmos;
490 cmos = dev_get_drvdata(container_of(kobj, struct device, kobj));
492 /* NOTE: on at least PCs and Ataris, the boot firmware uses a
493 * checksum on part of the NVRAM data. That's currently ignored
494 * here. If userspace is smart enough to know what fields of
495 * NVRAM to update, updating checksums is also part of its job.
498 spin_lock_irq(&rtc_lock);
499 for (retval = 0; count; count--, off++, retval++) {
500 /* don't trash RTC registers */
501 if (off == cmos->day_alrm
502 || off == cmos->mon_alrm
503 || off == cmos->century)
506 CMOS_WRITE(*buf++, off);
508 cmos_write_bank2(*buf++, off);
512 spin_unlock_irq(&rtc_lock);
517 static struct bin_attribute nvram = {
520 .mode = S_IRUGO | S_IWUSR,
523 .read = cmos_nvram_read,
524 .write = cmos_nvram_write,
525 /* size gets set up later */
528 /*----------------------------------------------------------------*/
530 static struct cmos_rtc cmos_rtc;
532 static irqreturn_t cmos_interrupt(int irq, void *p)
537 spin_lock(&rtc_lock);
539 /* When the HPET interrupt handler calls us, the interrupt
540 * status is passed as arg1 instead of the irq number. But
541 * always clear irq status, even when HPET is in the way.
543 * Note that HPET and RTC are almost certainly out of phase,
544 * giving different IRQ status ...
546 irqstat = CMOS_READ(RTC_INTR_FLAGS);
547 rtc_control = CMOS_READ(RTC_CONTROL);
548 if (is_hpet_enabled())
549 irqstat = (unsigned long)irq & 0xF0;
551 /* If we were suspended, RTC_CONTROL may not be accurate since the
552 * bios may have cleared it.
554 if (!cmos_rtc.suspend_ctrl)
555 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
557 irqstat &= (cmos_rtc.suspend_ctrl & 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 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
565 rtc_control &= ~RTC_AIE;
566 CMOS_WRITE(rtc_control, RTC_CONTROL);
567 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_get_platdata(dev);
591 unsigned char rtc_control;
592 unsigned address_space;
595 /* there can be only one ... */
602 /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
604 * REVISIT non-x86 systems may instead use memory space resources
605 * (needing ioremap etc), not i/o space resources like this ...
608 ports = request_region(ports->start, resource_size(ports),
611 ports = request_mem_region(ports->start, resource_size(ports),
614 dev_dbg(dev, "i/o registers already in use\n");
618 cmos_rtc.irq = rtc_irq;
619 cmos_rtc.iomem = ports;
621 /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
622 * driver did, but don't reject unknown configs. Old hardware
623 * won't address 128 bytes. Newer chips have multiple banks,
624 * though they may not be listed in one I/O resource.
626 #if defined(CONFIG_ATARI)
628 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
629 || defined(__sparc__) || defined(__mips__) \
630 || defined(__powerpc__) || defined(CONFIG_MN10300)
633 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
636 if (can_bank2 && ports->end > (ports->start + 1))
639 /* For ACPI systems extension info comes from the FADT. On others,
640 * board specific setup provides it as appropriate. Systems where
641 * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
642 * some almost-clones) can provide hooks to make that behave.
644 * Note that ACPI doesn't preclude putting these registers into
645 * "extended" areas of the chip, including some that we won't yet
646 * expect CMOS_READ and friends to handle.
651 if (info->address_space)
652 address_space = info->address_space;
654 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
655 cmos_rtc.day_alrm = info->rtc_day_alarm;
656 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
657 cmos_rtc.mon_alrm = info->rtc_mon_alarm;
658 if (info->rtc_century && info->rtc_century < 128)
659 cmos_rtc.century = info->rtc_century;
661 if (info->wake_on && info->wake_off) {
662 cmos_rtc.wake_on = info->wake_on;
663 cmos_rtc.wake_off = info->wake_off;
668 dev_set_drvdata(dev, &cmos_rtc);
670 cmos_rtc.rtc = rtc_device_register(driver_name, dev,
671 &cmos_rtc_ops, THIS_MODULE);
672 if (IS_ERR(cmos_rtc.rtc)) {
673 retval = PTR_ERR(cmos_rtc.rtc);
677 rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
679 spin_lock_irq(&rtc_lock);
681 if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
682 /* force periodic irq to CMOS reset default of 1024Hz;
684 * REVISIT it's been reported that at least one x86_64 ALI
685 * mobo doesn't use 32KHz here ... for portability we might
686 * need to do something about other clock frequencies.
688 cmos_rtc.rtc->irq_freq = 1024;
689 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
690 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
694 if (is_valid_irq(rtc_irq))
695 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
697 rtc_control = CMOS_READ(RTC_CONTROL);
699 spin_unlock_irq(&rtc_lock);
702 * <asm-generic/rtc.h> doesn't know 12-hour mode either.
704 if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
705 dev_warn(dev, "only 24-hr supported\n");
710 hpet_rtc_timer_init();
712 if (is_valid_irq(rtc_irq)) {
713 irq_handler_t rtc_cmos_int_handler;
715 if (is_hpet_enabled()) {
716 rtc_cmos_int_handler = hpet_rtc_interrupt;
717 retval = hpet_register_irq_handler(cmos_interrupt);
719 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
720 dev_warn(dev, "hpet_register_irq_handler "
721 " failed in rtc_init().");
725 rtc_cmos_int_handler = cmos_interrupt;
727 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
728 IRQF_SHARED, dev_name(&cmos_rtc.rtc->dev),
731 dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
736 /* export at least the first block of NVRAM */
737 nvram.size = address_space - NVRAM_OFFSET;
738 retval = sysfs_create_bin_file(&dev->kobj, &nvram);
740 dev_dbg(dev, "can't create nvram file? %d\n", retval);
744 dev_info(dev, "%s%s, %zd bytes nvram%s\n",
745 !is_valid_irq(rtc_irq) ? "no alarms" :
746 cmos_rtc.mon_alrm ? "alarms up to one year" :
747 cmos_rtc.day_alrm ? "alarms up to one month" :
748 "alarms up to one day",
749 cmos_rtc.century ? ", y3k" : "",
751 is_hpet_enabled() ? ", hpet irqs" : "");
756 if (is_valid_irq(rtc_irq))
757 free_irq(rtc_irq, cmos_rtc.rtc);
760 rtc_device_unregister(cmos_rtc.rtc);
763 release_region(ports->start, resource_size(ports));
765 release_mem_region(ports->start, resource_size(ports));
769 static void cmos_do_shutdown(int rtc_irq)
771 spin_lock_irq(&rtc_lock);
772 if (is_valid_irq(rtc_irq))
773 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
774 spin_unlock_irq(&rtc_lock);
777 static void __exit cmos_do_remove(struct device *dev)
779 struct cmos_rtc *cmos = dev_get_drvdata(dev);
780 struct resource *ports;
782 cmos_do_shutdown(cmos->irq);
784 sysfs_remove_bin_file(&dev->kobj, &nvram);
786 if (is_valid_irq(cmos->irq)) {
787 free_irq(cmos->irq, cmos->rtc);
788 hpet_unregister_irq_handler(cmos_interrupt);
791 rtc_device_unregister(cmos->rtc);
796 release_region(ports->start, resource_size(ports));
798 release_mem_region(ports->start, resource_size(ports));
804 static int cmos_aie_poweroff(struct device *dev)
806 struct cmos_rtc *cmos = dev_get_drvdata(dev);
810 unsigned char rtc_control;
812 if (!cmos->alarm_expires)
815 spin_lock_irq(&rtc_lock);
816 rtc_control = CMOS_READ(RTC_CONTROL);
817 spin_unlock_irq(&rtc_lock);
819 /* We only care about the situation where AIE is disabled. */
820 if (rtc_control & RTC_AIE)
823 cmos_read_time(dev, &now);
824 t_now = rtc_tm_to_time64(&now);
827 * When enabling "RTC wake-up" in BIOS setup, the machine reboots
828 * automatically right after shutdown on some buggy boxes.
829 * This automatic rebooting issue won't happen when the alarm
830 * time is larger than now+1 seconds.
832 * If the alarm time is equal to now+1 seconds, the issue can be
833 * prevented by cancelling the alarm.
835 if (cmos->alarm_expires == t_now + 1) {
836 struct rtc_wkalrm alarm;
838 /* Cancel the AIE timer by configuring the past time. */
839 rtc_time64_to_tm(t_now - 1, &alarm.time);
841 retval = cmos_set_alarm(dev, &alarm);
842 } else if (cmos->alarm_expires > t_now + 1) {
851 static int cmos_suspend(struct device *dev)
853 struct cmos_rtc *cmos = dev_get_drvdata(dev);
856 /* only the alarm might be a wakeup event source */
857 spin_lock_irq(&rtc_lock);
858 cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
859 if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
862 if (device_may_wakeup(dev))
863 mask = RTC_IRQMASK & ~RTC_AIE;
867 CMOS_WRITE(tmp, RTC_CONTROL);
868 hpet_mask_rtc_irq_bit(mask);
870 cmos_checkintr(cmos, tmp);
872 spin_unlock_irq(&rtc_lock);
875 cmos->enabled_wake = 1;
879 enable_irq_wake(cmos->irq);
882 dev_dbg(dev, "suspend%s, ctrl %02x\n",
883 (tmp & RTC_AIE) ? ", alarm may wake" : "",
889 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
890 * after a detour through G3 "mechanical off", although the ACPI spec
891 * says wakeup should only work from G1/S4 "hibernate". To most users,
892 * distinctions between S4 and S5 are pointless. So when the hardware
893 * allows, don't draw that distinction.
895 static inline int cmos_poweroff(struct device *dev)
897 return cmos_suspend(dev);
900 #ifdef CONFIG_PM_SLEEP
902 static int cmos_resume(struct device *dev)
904 struct cmos_rtc *cmos = dev_get_drvdata(dev);
907 if (cmos->enabled_wake) {
911 disable_irq_wake(cmos->irq);
912 cmos->enabled_wake = 0;
915 spin_lock_irq(&rtc_lock);
916 tmp = cmos->suspend_ctrl;
917 cmos->suspend_ctrl = 0;
918 /* re-enable any irqs previously active */
919 if (tmp & RTC_IRQMASK) {
922 if (device_may_wakeup(dev))
923 hpet_rtc_timer_init();
926 CMOS_WRITE(tmp, RTC_CONTROL);
927 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
929 mask = CMOS_READ(RTC_INTR_FLAGS);
930 mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
931 if (!is_hpet_enabled() || !is_intr(mask))
934 /* force one-shot behavior if HPET blocked
935 * the wake alarm's irq
937 rtc_update_irq(cmos->rtc, 1, mask);
939 hpet_mask_rtc_irq_bit(RTC_AIE);
940 } while (mask & RTC_AIE);
942 spin_unlock_irq(&rtc_lock);
944 dev_dbg(dev, "resume, ctrl %02x\n", tmp);
952 static inline int cmos_poweroff(struct device *dev)
959 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
961 /*----------------------------------------------------------------*/
963 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
964 * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
965 * probably list them in similar PNPBIOS tables; so PNP is more common.
967 * We don't use legacy "poke at the hardware" probing. Ancient PCs that
968 * predate even PNPBIOS should set up platform_bus devices.
973 #include <linux/acpi.h>
975 static u32 rtc_handler(void *context)
977 struct device *dev = context;
979 pm_wakeup_event(dev, 0);
980 acpi_clear_event(ACPI_EVENT_RTC);
981 acpi_disable_event(ACPI_EVENT_RTC, 0);
982 return ACPI_INTERRUPT_HANDLED;
985 static inline void rtc_wake_setup(struct device *dev)
987 acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
989 * After the RTC handler is installed, the Fixed_RTC event should
990 * be disabled. Only when the RTC alarm is set will it be enabled.
992 acpi_clear_event(ACPI_EVENT_RTC);
993 acpi_disable_event(ACPI_EVENT_RTC, 0);
996 static void rtc_wake_on(struct device *dev)
998 acpi_clear_event(ACPI_EVENT_RTC);
999 acpi_enable_event(ACPI_EVENT_RTC, 0);
1002 static void rtc_wake_off(struct device *dev)
1004 acpi_disable_event(ACPI_EVENT_RTC, 0);
1007 /* Every ACPI platform has a mc146818 compatible "cmos rtc". Here we find
1008 * its device node and pass extra config data. This helps its driver use
1009 * capabilities that the now-obsolete mc146818 didn't have, and informs it
1010 * that this board's RTC is wakeup-capable (per ACPI spec).
1012 static struct cmos_rtc_board_info acpi_rtc_info;
1014 static void cmos_wake_setup(struct device *dev)
1019 rtc_wake_setup(dev);
1020 acpi_rtc_info.wake_on = rtc_wake_on;
1021 acpi_rtc_info.wake_off = rtc_wake_off;
1023 /* workaround bug in some ACPI tables */
1024 if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1025 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1026 acpi_gbl_FADT.month_alarm);
1027 acpi_gbl_FADT.month_alarm = 0;
1030 acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1031 acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1032 acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1034 /* NOTE: S4_RTC_WAKE is NOT currently useful to Linux */
1035 if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1036 dev_info(dev, "RTC can wake from S4\n");
1038 dev->platform_data = &acpi_rtc_info;
1040 /* RTC always wakes from S1/S2/S3, and often S4/STD */
1041 device_init_wakeup(dev, 1);
1046 static void cmos_wake_setup(struct device *dev)
1054 #include <linux/pnp.h>
1056 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1058 cmos_wake_setup(&pnp->dev);
1060 if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0))
1061 /* Some machines contain a PNP entry for the RTC, but
1062 * don't define the IRQ. It should always be safe to
1063 * hardcode it in these cases
1065 return cmos_do_probe(&pnp->dev,
1066 pnp_get_resource(pnp, IORESOURCE_IO, 0), 8);
1068 return cmos_do_probe(&pnp->dev,
1069 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1073 static void __exit cmos_pnp_remove(struct pnp_dev *pnp)
1075 cmos_do_remove(&pnp->dev);
1078 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1080 struct device *dev = &pnp->dev;
1081 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1083 if (system_state == SYSTEM_POWER_OFF) {
1084 int retval = cmos_poweroff(dev);
1086 if (cmos_aie_poweroff(dev) < 0 && !retval)
1090 cmos_do_shutdown(cmos->irq);
1093 static const struct pnp_device_id rtc_ids[] = {
1094 { .id = "PNP0b00", },
1095 { .id = "PNP0b01", },
1096 { .id = "PNP0b02", },
1099 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1101 static struct pnp_driver cmos_pnp_driver = {
1102 .name = (char *) driver_name,
1103 .id_table = rtc_ids,
1104 .probe = cmos_pnp_probe,
1105 .remove = __exit_p(cmos_pnp_remove),
1106 .shutdown = cmos_pnp_shutdown,
1108 /* flag ensures resume() gets called, and stops syslog spam */
1109 .flags = PNP_DRIVER_RES_DO_NOT_CHANGE,
1115 #endif /* CONFIG_PNP */
1118 static const struct of_device_id of_cmos_match[] = {
1120 .compatible = "motorola,mc146818",
1124 MODULE_DEVICE_TABLE(of, of_cmos_match);
1126 static __init void cmos_of_init(struct platform_device *pdev)
1128 struct device_node *node = pdev->dev.of_node;
1129 struct rtc_time time;
1136 val = of_get_property(node, "ctrl-reg", NULL);
1138 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1140 val = of_get_property(node, "freq-reg", NULL);
1142 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1144 cmos_read_time(&pdev->dev, &time);
1145 ret = rtc_valid_tm(&time);
1147 struct rtc_time def_time = {
1151 cmos_set_time(&pdev->dev, &def_time);
1155 static inline void cmos_of_init(struct platform_device *pdev) {}
1157 /*----------------------------------------------------------------*/
1159 /* Platform setup should have set up an RTC device, when PNP is
1160 * unavailable ... this could happen even on (older) PCs.
1163 static int __init cmos_platform_probe(struct platform_device *pdev)
1165 struct resource *resource;
1169 cmos_wake_setup(&pdev->dev);
1172 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1174 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1175 irq = platform_get_irq(pdev, 0);
1179 return cmos_do_probe(&pdev->dev, resource, irq);
1182 static int __exit cmos_platform_remove(struct platform_device *pdev)
1184 cmos_do_remove(&pdev->dev);
1188 static void cmos_platform_shutdown(struct platform_device *pdev)
1190 struct device *dev = &pdev->dev;
1191 struct cmos_rtc *cmos = dev_get_drvdata(dev);
1193 if (system_state == SYSTEM_POWER_OFF) {
1194 int retval = cmos_poweroff(dev);
1196 if (cmos_aie_poweroff(dev) < 0 && !retval)
1200 cmos_do_shutdown(cmos->irq);
1203 /* work with hotplug and coldplug */
1204 MODULE_ALIAS("platform:rtc_cmos");
1206 static struct platform_driver cmos_platform_driver = {
1207 .remove = __exit_p(cmos_platform_remove),
1208 .shutdown = cmos_platform_shutdown,
1210 .name = driver_name,
1214 .of_match_table = of_match_ptr(of_cmos_match),
1219 static bool pnp_driver_registered;
1221 static bool platform_driver_registered;
1223 static int __init cmos_init(void)
1228 retval = pnp_register_driver(&cmos_pnp_driver);
1230 pnp_driver_registered = true;
1233 if (!cmos_rtc.dev) {
1234 retval = platform_driver_probe(&cmos_platform_driver,
1235 cmos_platform_probe);
1237 platform_driver_registered = true;
1244 if (pnp_driver_registered)
1245 pnp_unregister_driver(&cmos_pnp_driver);
1249 module_init(cmos_init);
1251 static void __exit cmos_exit(void)
1254 if (pnp_driver_registered)
1255 pnp_unregister_driver(&cmos_pnp_driver);
1257 if (platform_driver_registered)
1258 platform_driver_unregister(&cmos_platform_driver);
1260 module_exit(cmos_exit);
1263 MODULE_AUTHOR("David Brownell");
1264 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1265 MODULE_LICENSE("GPL");