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 <asm-generic/rtc.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 get_rtc_time().
194 * That'll make Y3K compatility (year > 2070) easy!
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 set_rtc_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
223 t
->time
.tm_mday
= -1;
226 spin_lock_irq(&rtc_lock
);
227 t
->time
.tm_sec
= CMOS_READ(RTC_SECONDS_ALARM
);
228 t
->time
.tm_min
= CMOS_READ(RTC_MINUTES_ALARM
);
229 t
->time
.tm_hour
= CMOS_READ(RTC_HOURS_ALARM
);
231 if (cmos
->day_alrm
) {
232 /* ignore upper bits on readback per ACPI spec */
233 t
->time
.tm_mday
= CMOS_READ(cmos
->day_alrm
) & 0x3f;
234 if (!t
->time
.tm_mday
)
235 t
->time
.tm_mday
= -1;
237 if (cmos
->mon_alrm
) {
238 t
->time
.tm_mon
= CMOS_READ(cmos
->mon_alrm
);
244 rtc_control
= CMOS_READ(RTC_CONTROL
);
245 spin_unlock_irq(&rtc_lock
);
247 if (!(rtc_control
& RTC_DM_BINARY
) || RTC_ALWAYS_BCD
) {
248 if (((unsigned)t
->time
.tm_sec
) < 0x60)
249 t
->time
.tm_sec
= bcd2bin(t
->time
.tm_sec
);
252 if (((unsigned)t
->time
.tm_min
) < 0x60)
253 t
->time
.tm_min
= bcd2bin(t
->time
.tm_min
);
256 if (((unsigned)t
->time
.tm_hour
) < 0x24)
257 t
->time
.tm_hour
= bcd2bin(t
->time
.tm_hour
);
259 t
->time
.tm_hour
= -1;
261 if (cmos
->day_alrm
) {
262 if (((unsigned)t
->time
.tm_mday
) <= 0x31)
263 t
->time
.tm_mday
= bcd2bin(t
->time
.tm_mday
);
265 t
->time
.tm_mday
= -1;
267 if (cmos
->mon_alrm
) {
268 if (((unsigned)t
->time
.tm_mon
) <= 0x12)
269 t
->time
.tm_mon
= bcd2bin(t
->time
.tm_mon
)-1;
275 t
->time
.tm_year
= -1;
277 t
->enabled
= !!(rtc_control
& RTC_AIE
);
283 static void cmos_checkintr(struct cmos_rtc
*cmos
, unsigned char rtc_control
)
285 unsigned char rtc_intr
;
287 /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
288 * allegedly some older rtcs need that to handle irqs properly
290 rtc_intr
= CMOS_READ(RTC_INTR_FLAGS
);
292 if (is_hpet_enabled())
295 rtc_intr
&= (rtc_control
& RTC_IRQMASK
) | RTC_IRQF
;
296 if (is_intr(rtc_intr
))
297 rtc_update_irq(cmos
->rtc
, 1, rtc_intr
);
300 static void cmos_irq_enable(struct cmos_rtc
*cmos
, unsigned char mask
)
302 unsigned char rtc_control
;
304 /* flush any pending IRQ status, notably for update irqs,
305 * before we enable new IRQs
307 rtc_control
= CMOS_READ(RTC_CONTROL
);
308 cmos_checkintr(cmos
, rtc_control
);
311 CMOS_WRITE(rtc_control
, RTC_CONTROL
);
312 hpet_set_rtc_irq_bit(mask
);
314 cmos_checkintr(cmos
, rtc_control
);
317 static void cmos_irq_disable(struct cmos_rtc
*cmos
, unsigned char mask
)
319 unsigned char rtc_control
;
321 rtc_control
= CMOS_READ(RTC_CONTROL
);
322 rtc_control
&= ~mask
;
323 CMOS_WRITE(rtc_control
, RTC_CONTROL
);
324 hpet_mask_rtc_irq_bit(mask
);
326 cmos_checkintr(cmos
, rtc_control
);
329 static int cmos_set_alarm(struct device
*dev
, struct rtc_wkalrm
*t
)
331 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
332 unsigned char mon
, mday
, hrs
, min
, sec
, rtc_control
;
334 if (!is_valid_irq(cmos
->irq
))
337 mon
= t
->time
.tm_mon
+ 1;
338 mday
= t
->time
.tm_mday
;
339 hrs
= t
->time
.tm_hour
;
340 min
= t
->time
.tm_min
;
341 sec
= t
->time
.tm_sec
;
343 rtc_control
= CMOS_READ(RTC_CONTROL
);
344 if (!(rtc_control
& RTC_DM_BINARY
) || RTC_ALWAYS_BCD
) {
345 /* Writing 0xff means "don't care" or "match all". */
346 mon
= (mon
<= 12) ? bin2bcd(mon
) : 0xff;
347 mday
= (mday
>= 1 && mday
<= 31) ? bin2bcd(mday
) : 0xff;
348 hrs
= (hrs
< 24) ? bin2bcd(hrs
) : 0xff;
349 min
= (min
< 60) ? bin2bcd(min
) : 0xff;
350 sec
= (sec
< 60) ? bin2bcd(sec
) : 0xff;
353 spin_lock_irq(&rtc_lock
);
355 /* next rtc irq must not be from previous alarm setting */
356 cmos_irq_disable(cmos
, RTC_AIE
);
359 CMOS_WRITE(hrs
, RTC_HOURS_ALARM
);
360 CMOS_WRITE(min
, RTC_MINUTES_ALARM
);
361 CMOS_WRITE(sec
, RTC_SECONDS_ALARM
);
363 /* the system may support an "enhanced" alarm */
364 if (cmos
->day_alrm
) {
365 CMOS_WRITE(mday
, cmos
->day_alrm
);
367 CMOS_WRITE(mon
, cmos
->mon_alrm
);
370 /* FIXME the HPET alarm glue currently ignores day_alrm
373 hpet_set_alarm_time(t
->time
.tm_hour
, t
->time
.tm_min
, t
->time
.tm_sec
);
376 cmos_irq_enable(cmos
, RTC_AIE
);
378 spin_unlock_irq(&rtc_lock
);
380 cmos
->alarm_expires
= rtc_tm_to_time64(&t
->time
);
385 static int cmos_alarm_irq_enable(struct device
*dev
, unsigned int enabled
)
387 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
390 if (!is_valid_irq(cmos
->irq
))
393 spin_lock_irqsave(&rtc_lock
, flags
);
396 cmos_irq_enable(cmos
, RTC_AIE
);
398 cmos_irq_disable(cmos
, RTC_AIE
);
400 spin_unlock_irqrestore(&rtc_lock
, flags
);
404 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
406 static int cmos_procfs(struct device
*dev
, struct seq_file
*seq
)
408 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
409 unsigned char rtc_control
, valid
;
411 spin_lock_irq(&rtc_lock
);
412 rtc_control
= CMOS_READ(RTC_CONTROL
);
413 valid
= CMOS_READ(RTC_VALID
);
414 spin_unlock_irq(&rtc_lock
);
416 /* NOTE: at least ICH6 reports battery status using a different
417 * (non-RTC) bit; and SQWE is ignored on many current systems.
420 "periodic_IRQ\t: %s\n"
422 "HPET_emulated\t: %s\n"
423 // "square_wave\t: %s\n"
426 "periodic_freq\t: %d\n"
427 "batt_status\t: %s\n",
428 (rtc_control
& RTC_PIE
) ? "yes" : "no",
429 (rtc_control
& RTC_UIE
) ? "yes" : "no",
430 is_hpet_enabled() ? "yes" : "no",
431 // (rtc_control & RTC_SQWE) ? "yes" : "no",
432 (rtc_control
& RTC_DM_BINARY
) ? "no" : "yes",
433 (rtc_control
& RTC_DST_EN
) ? "yes" : "no",
435 (valid
& RTC_VRT
) ? "okay" : "dead");
441 #define cmos_procfs NULL
444 static const struct rtc_class_ops cmos_rtc_ops
= {
445 .read_time
= cmos_read_time
,
446 .set_time
= cmos_set_time
,
447 .read_alarm
= cmos_read_alarm
,
448 .set_alarm
= cmos_set_alarm
,
450 .alarm_irq_enable
= cmos_alarm_irq_enable
,
453 /*----------------------------------------------------------------*/
456 * All these chips have at least 64 bytes of address space, shared by
457 * RTC registers and NVRAM. Most of those bytes of NVRAM are used
458 * by boot firmware. Modern chips have 128 or 256 bytes.
461 #define NVRAM_OFFSET (RTC_REG_D + 1)
464 cmos_nvram_read(struct file
*filp
, struct kobject
*kobj
,
465 struct bin_attribute
*attr
,
466 char *buf
, loff_t off
, size_t count
)
470 if (unlikely(off
>= attr
->size
))
472 if (unlikely(off
< 0))
474 if ((off
+ count
) > attr
->size
)
475 count
= attr
->size
- off
;
478 spin_lock_irq(&rtc_lock
);
479 for (retval
= 0; count
; count
--, off
++, retval
++) {
481 *buf
++ = CMOS_READ(off
);
483 *buf
++ = cmos_read_bank2(off
);
487 spin_unlock_irq(&rtc_lock
);
493 cmos_nvram_write(struct file
*filp
, struct kobject
*kobj
,
494 struct bin_attribute
*attr
,
495 char *buf
, loff_t off
, size_t count
)
497 struct cmos_rtc
*cmos
;
500 cmos
= dev_get_drvdata(container_of(kobj
, struct device
, kobj
));
501 if (unlikely(off
>= attr
->size
))
503 if (unlikely(off
< 0))
505 if ((off
+ count
) > attr
->size
)
506 count
= attr
->size
- off
;
508 /* NOTE: on at least PCs and Ataris, the boot firmware uses a
509 * checksum on part of the NVRAM data. That's currently ignored
510 * here. If userspace is smart enough to know what fields of
511 * NVRAM to update, updating checksums is also part of its job.
514 spin_lock_irq(&rtc_lock
);
515 for (retval
= 0; count
; count
--, off
++, retval
++) {
516 /* don't trash RTC registers */
517 if (off
== cmos
->day_alrm
518 || off
== cmos
->mon_alrm
519 || off
== cmos
->century
)
522 CMOS_WRITE(*buf
++, off
);
524 cmos_write_bank2(*buf
++, off
);
528 spin_unlock_irq(&rtc_lock
);
533 static struct bin_attribute nvram
= {
536 .mode
= S_IRUGO
| S_IWUSR
,
539 .read
= cmos_nvram_read
,
540 .write
= cmos_nvram_write
,
541 /* size gets set up later */
544 /*----------------------------------------------------------------*/
546 static struct cmos_rtc cmos_rtc
;
548 static irqreturn_t
cmos_interrupt(int irq
, void *p
)
553 spin_lock(&rtc_lock
);
555 /* When the HPET interrupt handler calls us, the interrupt
556 * status is passed as arg1 instead of the irq number. But
557 * always clear irq status, even when HPET is in the way.
559 * Note that HPET and RTC are almost certainly out of phase,
560 * giving different IRQ status ...
562 irqstat
= CMOS_READ(RTC_INTR_FLAGS
);
563 rtc_control
= CMOS_READ(RTC_CONTROL
);
564 if (is_hpet_enabled())
565 irqstat
= (unsigned long)irq
& 0xF0;
567 /* If we were suspended, RTC_CONTROL may not be accurate since the
568 * bios may have cleared it.
570 if (!cmos_rtc
.suspend_ctrl
)
571 irqstat
&= (rtc_control
& RTC_IRQMASK
) | RTC_IRQF
;
573 irqstat
&= (cmos_rtc
.suspend_ctrl
& RTC_IRQMASK
) | RTC_IRQF
;
575 /* All Linux RTC alarms should be treated as if they were oneshot.
576 * Similar code may be needed in system wakeup paths, in case the
577 * alarm woke the system.
579 if (irqstat
& RTC_AIE
) {
580 cmos_rtc
.suspend_ctrl
&= ~RTC_AIE
;
581 rtc_control
&= ~RTC_AIE
;
582 CMOS_WRITE(rtc_control
, RTC_CONTROL
);
583 hpet_mask_rtc_irq_bit(RTC_AIE
);
584 CMOS_READ(RTC_INTR_FLAGS
);
586 spin_unlock(&rtc_lock
);
588 if (is_intr(irqstat
)) {
589 rtc_update_irq(p
, 1, irqstat
);
599 #define INITSECTION __init
602 static int INITSECTION
603 cmos_do_probe(struct device
*dev
, struct resource
*ports
, int rtc_irq
)
605 struct cmos_rtc_board_info
*info
= dev_get_platdata(dev
);
607 unsigned char rtc_control
;
608 unsigned address_space
;
611 /* there can be only one ... */
618 /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
620 * REVISIT non-x86 systems may instead use memory space resources
621 * (needing ioremap etc), not i/o space resources like this ...
624 ports
= request_region(ports
->start
, resource_size(ports
),
627 ports
= request_mem_region(ports
->start
, resource_size(ports
),
630 dev_dbg(dev
, "i/o registers already in use\n");
634 cmos_rtc
.irq
= rtc_irq
;
635 cmos_rtc
.iomem
= ports
;
637 /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
638 * driver did, but don't reject unknown configs. Old hardware
639 * won't address 128 bytes. Newer chips have multiple banks,
640 * though they may not be listed in one I/O resource.
642 #if defined(CONFIG_ATARI)
644 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
645 || defined(__sparc__) || defined(__mips__) \
646 || defined(__powerpc__)
649 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
652 if (can_bank2
&& ports
->end
> (ports
->start
+ 1))
655 /* For ACPI systems extension info comes from the FADT. On others,
656 * board specific setup provides it as appropriate. Systems where
657 * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
658 * some almost-clones) can provide hooks to make that behave.
660 * Note that ACPI doesn't preclude putting these registers into
661 * "extended" areas of the chip, including some that we won't yet
662 * expect CMOS_READ and friends to handle.
667 if (info
->address_space
)
668 address_space
= info
->address_space
;
670 if (info
->rtc_day_alarm
&& info
->rtc_day_alarm
< 128)
671 cmos_rtc
.day_alrm
= info
->rtc_day_alarm
;
672 if (info
->rtc_mon_alarm
&& info
->rtc_mon_alarm
< 128)
673 cmos_rtc
.mon_alrm
= info
->rtc_mon_alarm
;
674 if (info
->rtc_century
&& info
->rtc_century
< 128)
675 cmos_rtc
.century
= info
->rtc_century
;
677 if (info
->wake_on
&& info
->wake_off
) {
678 cmos_rtc
.wake_on
= info
->wake_on
;
679 cmos_rtc
.wake_off
= info
->wake_off
;
684 dev_set_drvdata(dev
, &cmos_rtc
);
686 cmos_rtc
.rtc
= rtc_device_register(driver_name
, dev
,
687 &cmos_rtc_ops
, THIS_MODULE
);
688 if (IS_ERR(cmos_rtc
.rtc
)) {
689 retval
= PTR_ERR(cmos_rtc
.rtc
);
693 rename_region(ports
, dev_name(&cmos_rtc
.rtc
->dev
));
695 spin_lock_irq(&rtc_lock
);
697 if (!(flags
& CMOS_RTC_FLAGS_NOFREQ
)) {
698 /* force periodic irq to CMOS reset default of 1024Hz;
700 * REVISIT it's been reported that at least one x86_64 ALI
701 * mobo doesn't use 32KHz here ... for portability we might
702 * need to do something about other clock frequencies.
704 cmos_rtc
.rtc
->irq_freq
= 1024;
705 hpet_set_periodic_freq(cmos_rtc
.rtc
->irq_freq
);
706 CMOS_WRITE(RTC_REF_CLCK_32KHZ
| 0x06, RTC_FREQ_SELECT
);
710 if (is_valid_irq(rtc_irq
))
711 cmos_irq_disable(&cmos_rtc
, RTC_PIE
| RTC_AIE
| RTC_UIE
);
713 rtc_control
= CMOS_READ(RTC_CONTROL
);
715 spin_unlock_irq(&rtc_lock
);
718 * <asm-generic/rtc.h> doesn't know 12-hour mode either.
720 if (is_valid_irq(rtc_irq
) && !(rtc_control
& RTC_24H
)) {
721 dev_warn(dev
, "only 24-hr supported\n");
726 if (is_valid_irq(rtc_irq
)) {
727 irq_handler_t rtc_cmos_int_handler
;
729 if (is_hpet_enabled()) {
730 rtc_cmos_int_handler
= hpet_rtc_interrupt
;
731 retval
= hpet_register_irq_handler(cmos_interrupt
);
733 dev_warn(dev
, "hpet_register_irq_handler "
734 " failed in rtc_init().");
738 rtc_cmos_int_handler
= cmos_interrupt
;
740 retval
= request_irq(rtc_irq
, rtc_cmos_int_handler
,
741 0, dev_name(&cmos_rtc
.rtc
->dev
),
744 dev_dbg(dev
, "IRQ %d is already in use\n", rtc_irq
);
748 hpet_rtc_timer_init();
750 /* export at least the first block of NVRAM */
751 nvram
.size
= address_space
- NVRAM_OFFSET
;
752 retval
= sysfs_create_bin_file(&dev
->kobj
, &nvram
);
754 dev_dbg(dev
, "can't create nvram file? %d\n", retval
);
758 dev_info(dev
, "%s%s, %zd bytes nvram%s\n",
759 !is_valid_irq(rtc_irq
) ? "no alarms" :
760 cmos_rtc
.mon_alrm
? "alarms up to one year" :
761 cmos_rtc
.day_alrm
? "alarms up to one month" :
762 "alarms up to one day",
763 cmos_rtc
.century
? ", y3k" : "",
765 is_hpet_enabled() ? ", hpet irqs" : "");
770 if (is_valid_irq(rtc_irq
))
771 free_irq(rtc_irq
, cmos_rtc
.rtc
);
774 rtc_device_unregister(cmos_rtc
.rtc
);
777 release_region(ports
->start
, resource_size(ports
));
779 release_mem_region(ports
->start
, resource_size(ports
));
783 static void cmos_do_shutdown(int rtc_irq
)
785 spin_lock_irq(&rtc_lock
);
786 if (is_valid_irq(rtc_irq
))
787 cmos_irq_disable(&cmos_rtc
, RTC_IRQMASK
);
788 spin_unlock_irq(&rtc_lock
);
791 static void __exit
cmos_do_remove(struct device
*dev
)
793 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
794 struct resource
*ports
;
796 cmos_do_shutdown(cmos
->irq
);
798 sysfs_remove_bin_file(&dev
->kobj
, &nvram
);
800 if (is_valid_irq(cmos
->irq
)) {
801 free_irq(cmos
->irq
, cmos
->rtc
);
802 hpet_unregister_irq_handler(cmos_interrupt
);
805 rtc_device_unregister(cmos
->rtc
);
810 release_region(ports
->start
, resource_size(ports
));
812 release_mem_region(ports
->start
, resource_size(ports
));
818 static int cmos_aie_poweroff(struct device
*dev
)
820 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
824 unsigned char rtc_control
;
826 if (!cmos
->alarm_expires
)
829 spin_lock_irq(&rtc_lock
);
830 rtc_control
= CMOS_READ(RTC_CONTROL
);
831 spin_unlock_irq(&rtc_lock
);
833 /* We only care about the situation where AIE is disabled. */
834 if (rtc_control
& RTC_AIE
)
837 cmos_read_time(dev
, &now
);
838 t_now
= rtc_tm_to_time64(&now
);
841 * When enabling "RTC wake-up" in BIOS setup, the machine reboots
842 * automatically right after shutdown on some buggy boxes.
843 * This automatic rebooting issue won't happen when the alarm
844 * time is larger than now+1 seconds.
846 * If the alarm time is equal to now+1 seconds, the issue can be
847 * prevented by cancelling the alarm.
849 if (cmos
->alarm_expires
== t_now
+ 1) {
850 struct rtc_wkalrm alarm
;
852 /* Cancel the AIE timer by configuring the past time. */
853 rtc_time64_to_tm(t_now
- 1, &alarm
.time
);
855 retval
= cmos_set_alarm(dev
, &alarm
);
856 } else if (cmos
->alarm_expires
> t_now
+ 1) {
865 static int cmos_suspend(struct device
*dev
)
867 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
870 /* only the alarm might be a wakeup event source */
871 spin_lock_irq(&rtc_lock
);
872 cmos
->suspend_ctrl
= tmp
= CMOS_READ(RTC_CONTROL
);
873 if (tmp
& (RTC_PIE
|RTC_AIE
|RTC_UIE
)) {
876 if (device_may_wakeup(dev
))
877 mask
= RTC_IRQMASK
& ~RTC_AIE
;
881 CMOS_WRITE(tmp
, RTC_CONTROL
);
882 hpet_mask_rtc_irq_bit(mask
);
884 cmos_checkintr(cmos
, tmp
);
886 spin_unlock_irq(&rtc_lock
);
889 cmos
->enabled_wake
= 1;
893 enable_irq_wake(cmos
->irq
);
896 dev_dbg(dev
, "suspend%s, ctrl %02x\n",
897 (tmp
& RTC_AIE
) ? ", alarm may wake" : "",
903 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
904 * after a detour through G3 "mechanical off", although the ACPI spec
905 * says wakeup should only work from G1/S4 "hibernate". To most users,
906 * distinctions between S4 and S5 are pointless. So when the hardware
907 * allows, don't draw that distinction.
909 static inline int cmos_poweroff(struct device
*dev
)
911 return cmos_suspend(dev
);
914 #ifdef CONFIG_PM_SLEEP
916 static int cmos_resume(struct device
*dev
)
918 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
921 if (cmos
->enabled_wake
) {
925 disable_irq_wake(cmos
->irq
);
926 cmos
->enabled_wake
= 0;
929 spin_lock_irq(&rtc_lock
);
930 tmp
= cmos
->suspend_ctrl
;
931 cmos
->suspend_ctrl
= 0;
932 /* re-enable any irqs previously active */
933 if (tmp
& RTC_IRQMASK
) {
936 if (device_may_wakeup(dev
))
937 hpet_rtc_timer_init();
940 CMOS_WRITE(tmp
, RTC_CONTROL
);
941 hpet_set_rtc_irq_bit(tmp
& RTC_IRQMASK
);
943 mask
= CMOS_READ(RTC_INTR_FLAGS
);
944 mask
&= (tmp
& RTC_IRQMASK
) | RTC_IRQF
;
945 if (!is_hpet_enabled() || !is_intr(mask
))
948 /* force one-shot behavior if HPET blocked
949 * the wake alarm's irq
951 rtc_update_irq(cmos
->rtc
, 1, mask
);
953 hpet_mask_rtc_irq_bit(RTC_AIE
);
954 } while (mask
& RTC_AIE
);
956 spin_unlock_irq(&rtc_lock
);
958 dev_dbg(dev
, "resume, ctrl %02x\n", tmp
);
966 static inline int cmos_poweroff(struct device
*dev
)
973 static SIMPLE_DEV_PM_OPS(cmos_pm_ops
, cmos_suspend
, cmos_resume
);
975 /*----------------------------------------------------------------*/
977 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
978 * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
979 * probably list them in similar PNPBIOS tables; so PNP is more common.
981 * We don't use legacy "poke at the hardware" probing. Ancient PCs that
982 * predate even PNPBIOS should set up platform_bus devices.
987 #include <linux/acpi.h>
989 static u32
rtc_handler(void *context
)
991 struct device
*dev
= context
;
993 pm_wakeup_event(dev
, 0);
994 acpi_clear_event(ACPI_EVENT_RTC
);
995 acpi_disable_event(ACPI_EVENT_RTC
, 0);
996 return ACPI_INTERRUPT_HANDLED
;
999 static inline void rtc_wake_setup(struct device
*dev
)
1001 acpi_install_fixed_event_handler(ACPI_EVENT_RTC
, rtc_handler
, dev
);
1003 * After the RTC handler is installed, the Fixed_RTC event should
1004 * be disabled. Only when the RTC alarm is set will it be enabled.
1006 acpi_clear_event(ACPI_EVENT_RTC
);
1007 acpi_disable_event(ACPI_EVENT_RTC
, 0);
1010 static void rtc_wake_on(struct device
*dev
)
1012 acpi_clear_event(ACPI_EVENT_RTC
);
1013 acpi_enable_event(ACPI_EVENT_RTC
, 0);
1016 static void rtc_wake_off(struct device
*dev
)
1018 acpi_disable_event(ACPI_EVENT_RTC
, 0);
1021 /* Every ACPI platform has a mc146818 compatible "cmos rtc". Here we find
1022 * its device node and pass extra config data. This helps its driver use
1023 * capabilities that the now-obsolete mc146818 didn't have, and informs it
1024 * that this board's RTC is wakeup-capable (per ACPI spec).
1026 static struct cmos_rtc_board_info acpi_rtc_info
;
1028 static void cmos_wake_setup(struct device
*dev
)
1033 rtc_wake_setup(dev
);
1034 acpi_rtc_info
.wake_on
= rtc_wake_on
;
1035 acpi_rtc_info
.wake_off
= rtc_wake_off
;
1037 /* workaround bug in some ACPI tables */
1038 if (acpi_gbl_FADT
.month_alarm
&& !acpi_gbl_FADT
.day_alarm
) {
1039 dev_dbg(dev
, "bogus FADT month_alarm (%d)\n",
1040 acpi_gbl_FADT
.month_alarm
);
1041 acpi_gbl_FADT
.month_alarm
= 0;
1044 acpi_rtc_info
.rtc_day_alarm
= acpi_gbl_FADT
.day_alarm
;
1045 acpi_rtc_info
.rtc_mon_alarm
= acpi_gbl_FADT
.month_alarm
;
1046 acpi_rtc_info
.rtc_century
= acpi_gbl_FADT
.century
;
1048 /* NOTE: S4_RTC_WAKE is NOT currently useful to Linux */
1049 if (acpi_gbl_FADT
.flags
& ACPI_FADT_S4_RTC_WAKE
)
1050 dev_info(dev
, "RTC can wake from S4\n");
1052 dev
->platform_data
= &acpi_rtc_info
;
1054 /* RTC always wakes from S1/S2/S3, and often S4/STD */
1055 device_init_wakeup(dev
, 1);
1060 static void cmos_wake_setup(struct device
*dev
)
1068 #include <linux/pnp.h>
1070 static int cmos_pnp_probe(struct pnp_dev
*pnp
, const struct pnp_device_id
*id
)
1072 cmos_wake_setup(&pnp
->dev
);
1074 if (pnp_port_start(pnp
, 0) == 0x70 && !pnp_irq_valid(pnp
, 0))
1075 /* Some machines contain a PNP entry for the RTC, but
1076 * don't define the IRQ. It should always be safe to
1077 * hardcode it in these cases
1079 return cmos_do_probe(&pnp
->dev
,
1080 pnp_get_resource(pnp
, IORESOURCE_IO
, 0), 8);
1082 return cmos_do_probe(&pnp
->dev
,
1083 pnp_get_resource(pnp
, IORESOURCE_IO
, 0),
1087 static void __exit
cmos_pnp_remove(struct pnp_dev
*pnp
)
1089 cmos_do_remove(&pnp
->dev
);
1092 static void cmos_pnp_shutdown(struct pnp_dev
*pnp
)
1094 struct device
*dev
= &pnp
->dev
;
1095 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
1097 if (system_state
== SYSTEM_POWER_OFF
) {
1098 int retval
= cmos_poweroff(dev
);
1100 if (cmos_aie_poweroff(dev
) < 0 && !retval
)
1104 cmos_do_shutdown(cmos
->irq
);
1107 static const struct pnp_device_id rtc_ids
[] = {
1108 { .id
= "PNP0b00", },
1109 { .id
= "PNP0b01", },
1110 { .id
= "PNP0b02", },
1113 MODULE_DEVICE_TABLE(pnp
, rtc_ids
);
1115 static struct pnp_driver cmos_pnp_driver
= {
1116 .name
= (char *) driver_name
,
1117 .id_table
= rtc_ids
,
1118 .probe
= cmos_pnp_probe
,
1119 .remove
= __exit_p(cmos_pnp_remove
),
1120 .shutdown
= cmos_pnp_shutdown
,
1122 /* flag ensures resume() gets called, and stops syslog spam */
1123 .flags
= PNP_DRIVER_RES_DO_NOT_CHANGE
,
1129 #endif /* CONFIG_PNP */
1132 static const struct of_device_id of_cmos_match
[] = {
1134 .compatible
= "motorola,mc146818",
1138 MODULE_DEVICE_TABLE(of
, of_cmos_match
);
1140 static __init
void cmos_of_init(struct platform_device
*pdev
)
1142 struct device_node
*node
= pdev
->dev
.of_node
;
1143 struct rtc_time time
;
1150 val
= of_get_property(node
, "ctrl-reg", NULL
);
1152 CMOS_WRITE(be32_to_cpup(val
), RTC_CONTROL
);
1154 val
= of_get_property(node
, "freq-reg", NULL
);
1156 CMOS_WRITE(be32_to_cpup(val
), RTC_FREQ_SELECT
);
1158 get_rtc_time(&time
);
1159 ret
= rtc_valid_tm(&time
);
1161 struct rtc_time def_time
= {
1165 set_rtc_time(&def_time
);
1169 static inline void cmos_of_init(struct platform_device
*pdev
) {}
1171 /*----------------------------------------------------------------*/
1173 /* Platform setup should have set up an RTC device, when PNP is
1174 * unavailable ... this could happen even on (older) PCs.
1177 static int __init
cmos_platform_probe(struct platform_device
*pdev
)
1179 struct resource
*resource
;
1183 cmos_wake_setup(&pdev
->dev
);
1186 resource
= platform_get_resource(pdev
, IORESOURCE_IO
, 0);
1188 resource
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
1189 irq
= platform_get_irq(pdev
, 0);
1193 return cmos_do_probe(&pdev
->dev
, resource
, irq
);
1196 static int __exit
cmos_platform_remove(struct platform_device
*pdev
)
1198 cmos_do_remove(&pdev
->dev
);
1202 static void cmos_platform_shutdown(struct platform_device
*pdev
)
1204 struct device
*dev
= &pdev
->dev
;
1205 struct cmos_rtc
*cmos
= dev_get_drvdata(dev
);
1207 if (system_state
== SYSTEM_POWER_OFF
) {
1208 int retval
= cmos_poweroff(dev
);
1210 if (cmos_aie_poweroff(dev
) < 0 && !retval
)
1214 cmos_do_shutdown(cmos
->irq
);
1217 /* work with hotplug and coldplug */
1218 MODULE_ALIAS("platform:rtc_cmos");
1220 static struct platform_driver cmos_platform_driver
= {
1221 .remove
= __exit_p(cmos_platform_remove
),
1222 .shutdown
= cmos_platform_shutdown
,
1224 .name
= driver_name
,
1228 .of_match_table
= of_match_ptr(of_cmos_match
),
1233 static bool pnp_driver_registered
;
1235 static bool platform_driver_registered
;
1237 static int __init
cmos_init(void)
1242 retval
= pnp_register_driver(&cmos_pnp_driver
);
1244 pnp_driver_registered
= true;
1247 if (!cmos_rtc
.dev
) {
1248 retval
= platform_driver_probe(&cmos_platform_driver
,
1249 cmos_platform_probe
);
1251 platform_driver_registered
= true;
1258 if (pnp_driver_registered
)
1259 pnp_unregister_driver(&cmos_pnp_driver
);
1263 module_init(cmos_init
);
1265 static void __exit
cmos_exit(void)
1268 if (pnp_driver_registered
)
1269 pnp_unregister_driver(&cmos_pnp_driver
);
1271 if (platform_driver_registered
)
1272 platform_driver_unregister(&cmos_platform_driver
);
1274 module_exit(cmos_exit
);
1277 MODULE_AUTHOR("David Brownell");
1278 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1279 MODULE_LICENSE("GPL");