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[pohmelfs.git] / drivers / rtc / rtc-cmos.c
blobd7782aa099439575a1a4f1887190b70a1b5e6370
1 /*
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>
39 #include <linux/pm.h>
40 #include <linux/of.h>
41 #include <linux/of_platform.h>
43 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
44 #include <asm-generic/rtc.h>
46 struct cmos_rtc {
47 struct rtc_device *rtc;
48 struct device *dev;
49 int irq;
50 struct resource *iomem;
52 void (*wake_on)(struct device *);
53 void (*wake_off)(struct device *);
55 u8 enabled_wake;
56 u8 suspend_ctrl;
58 /* newer hardware extends the original register set */
59 u8 day_alrm;
60 u8 mon_alrm;
61 u8 century;
64 /* both platform and pnp busses use negative numbers for invalid irqs */
65 #define is_valid_irq(n) ((n) > 0)
67 static const char driver_name[] = "rtc_cmos";
69 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
70 * always mask it against the irq enable bits in RTC_CONTROL. Bit values
71 * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
73 #define RTC_IRQMASK (RTC_PF | RTC_AF | RTC_UF)
75 static inline int is_intr(u8 rtc_intr)
77 if (!(rtc_intr & RTC_IRQF))
78 return 0;
79 return rtc_intr & RTC_IRQMASK;
82 /*----------------------------------------------------------------*/
84 /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
85 * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
86 * used in a broken "legacy replacement" mode. The breakage includes
87 * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
88 * other (better) use.
90 * When that broken mode is in use, platform glue provides a partial
91 * emulation of hardware RTC IRQ facilities using HPET #1. We don't
92 * want to use HPET for anything except those IRQs though...
94 #ifdef CONFIG_HPET_EMULATE_RTC
95 #include <asm/hpet.h>
96 #else
98 static inline int is_hpet_enabled(void)
100 return 0;
103 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
105 return 0;
108 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
110 return 0;
113 static inline int
114 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
116 return 0;
119 static inline int hpet_set_periodic_freq(unsigned long freq)
121 return 0;
124 static inline int hpet_rtc_dropped_irq(void)
126 return 0;
129 static inline int hpet_rtc_timer_init(void)
131 return 0;
134 extern irq_handler_t hpet_rtc_interrupt;
136 static inline int hpet_register_irq_handler(irq_handler_t handler)
138 return 0;
141 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
143 return 0;
146 #endif
148 /*----------------------------------------------------------------*/
150 #ifdef RTC_PORT
152 /* Most newer x86 systems have two register banks, the first used
153 * for RTC and NVRAM and the second only for NVRAM. Caller must
154 * own rtc_lock ... and we won't worry about access during NMI.
156 #define can_bank2 true
158 static inline unsigned char cmos_read_bank2(unsigned char addr)
160 outb(addr, RTC_PORT(2));
161 return inb(RTC_PORT(3));
164 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
166 outb(addr, RTC_PORT(2));
167 outb(val, RTC_PORT(3));
170 #else
172 #define can_bank2 false
174 static inline unsigned char cmos_read_bank2(unsigned char addr)
176 return 0;
179 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
183 #endif
185 /*----------------------------------------------------------------*/
187 static int cmos_read_time(struct device *dev, struct rtc_time *t)
189 /* REVISIT: if the clock has a "century" register, use
190 * that instead of the heuristic in get_rtc_time().
191 * That'll make Y3K compatility (year > 2070) easy!
193 get_rtc_time(t);
194 return 0;
197 static int cmos_set_time(struct device *dev, struct rtc_time *t)
199 /* REVISIT: set the "century" register if available
201 * NOTE: this ignores the issue whereby updating the seconds
202 * takes effect exactly 500ms after we write the register.
203 * (Also queueing and other delays before we get this far.)
205 return set_rtc_time(t);
208 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
210 struct cmos_rtc *cmos = dev_get_drvdata(dev);
211 unsigned char rtc_control;
213 if (!is_valid_irq(cmos->irq))
214 return -EIO;
216 /* Basic alarms only support hour, minute, and seconds fields.
217 * Some also support day and month, for alarms up to a year in
218 * the future.
220 t->time.tm_mday = -1;
221 t->time.tm_mon = -1;
223 spin_lock_irq(&rtc_lock);
224 t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
225 t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
226 t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
228 if (cmos->day_alrm) {
229 /* ignore upper bits on readback per ACPI spec */
230 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
231 if (!t->time.tm_mday)
232 t->time.tm_mday = -1;
234 if (cmos->mon_alrm) {
235 t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
236 if (!t->time.tm_mon)
237 t->time.tm_mon = -1;
241 rtc_control = CMOS_READ(RTC_CONTROL);
242 spin_unlock_irq(&rtc_lock);
244 if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
245 if (((unsigned)t->time.tm_sec) < 0x60)
246 t->time.tm_sec = bcd2bin(t->time.tm_sec);
247 else
248 t->time.tm_sec = -1;
249 if (((unsigned)t->time.tm_min) < 0x60)
250 t->time.tm_min = bcd2bin(t->time.tm_min);
251 else
252 t->time.tm_min = -1;
253 if (((unsigned)t->time.tm_hour) < 0x24)
254 t->time.tm_hour = bcd2bin(t->time.tm_hour);
255 else
256 t->time.tm_hour = -1;
258 if (cmos->day_alrm) {
259 if (((unsigned)t->time.tm_mday) <= 0x31)
260 t->time.tm_mday = bcd2bin(t->time.tm_mday);
261 else
262 t->time.tm_mday = -1;
264 if (cmos->mon_alrm) {
265 if (((unsigned)t->time.tm_mon) <= 0x12)
266 t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
267 else
268 t->time.tm_mon = -1;
272 t->time.tm_year = -1;
274 t->enabled = !!(rtc_control & RTC_AIE);
275 t->pending = 0;
277 return 0;
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())
290 return;
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);
307 rtc_control |= mask;
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))
332 return -EIO;
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);
355 /* update alarm */
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);
363 if (cmos->mon_alrm)
364 CMOS_WRITE(mon, cmos->mon_alrm);
367 /* FIXME the HPET alarm glue currently ignores day_alrm
368 * and mon_alrm ...
370 hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
372 if (t->enabled)
373 cmos_irq_enable(cmos, RTC_AIE);
375 spin_unlock_irq(&rtc_lock);
377 return 0;
380 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
382 struct cmos_rtc *cmos = dev_get_drvdata(dev);
383 unsigned long flags;
385 if (!is_valid_irq(cmos->irq))
386 return -EINVAL;
388 spin_lock_irqsave(&rtc_lock, flags);
390 if (enabled)
391 cmos_irq_enable(cmos, RTC_AIE);
392 else
393 cmos_irq_disable(cmos, RTC_AIE);
395 spin_unlock_irqrestore(&rtc_lock, flags);
396 return 0;
399 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
401 static int cmos_procfs(struct device *dev, struct seq_file *seq)
403 struct cmos_rtc *cmos = dev_get_drvdata(dev);
404 unsigned char rtc_control, valid;
406 spin_lock_irq(&rtc_lock);
407 rtc_control = CMOS_READ(RTC_CONTROL);
408 valid = CMOS_READ(RTC_VALID);
409 spin_unlock_irq(&rtc_lock);
411 /* NOTE: at least ICH6 reports battery status using a different
412 * (non-RTC) bit; and SQWE is ignored on many current systems.
414 return seq_printf(seq,
415 "periodic_IRQ\t: %s\n"
416 "update_IRQ\t: %s\n"
417 "HPET_emulated\t: %s\n"
418 // "square_wave\t: %s\n"
419 "BCD\t\t: %s\n"
420 "DST_enable\t: %s\n"
421 "periodic_freq\t: %d\n"
422 "batt_status\t: %s\n",
423 (rtc_control & RTC_PIE) ? "yes" : "no",
424 (rtc_control & RTC_UIE) ? "yes" : "no",
425 is_hpet_enabled() ? "yes" : "no",
426 // (rtc_control & RTC_SQWE) ? "yes" : "no",
427 (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
428 (rtc_control & RTC_DST_EN) ? "yes" : "no",
429 cmos->rtc->irq_freq,
430 (valid & RTC_VRT) ? "okay" : "dead");
433 #else
434 #define cmos_procfs NULL
435 #endif
437 static const struct rtc_class_ops cmos_rtc_ops = {
438 .read_time = cmos_read_time,
439 .set_time = cmos_set_time,
440 .read_alarm = cmos_read_alarm,
441 .set_alarm = cmos_set_alarm,
442 .proc = cmos_procfs,
443 .alarm_irq_enable = cmos_alarm_irq_enable,
446 /*----------------------------------------------------------------*/
449 * All these chips have at least 64 bytes of address space, shared by
450 * RTC registers and NVRAM. Most of those bytes of NVRAM are used
451 * by boot firmware. Modern chips have 128 or 256 bytes.
454 #define NVRAM_OFFSET (RTC_REG_D + 1)
456 static ssize_t
457 cmos_nvram_read(struct file *filp, struct kobject *kobj,
458 struct bin_attribute *attr,
459 char *buf, loff_t off, size_t count)
461 int retval;
463 if (unlikely(off >= attr->size))
464 return 0;
465 if (unlikely(off < 0))
466 return -EINVAL;
467 if ((off + count) > attr->size)
468 count = attr->size - off;
470 off += NVRAM_OFFSET;
471 spin_lock_irq(&rtc_lock);
472 for (retval = 0; count; count--, off++, retval++) {
473 if (off < 128)
474 *buf++ = CMOS_READ(off);
475 else if (can_bank2)
476 *buf++ = cmos_read_bank2(off);
477 else
478 break;
480 spin_unlock_irq(&rtc_lock);
482 return retval;
485 static ssize_t
486 cmos_nvram_write(struct file *filp, struct kobject *kobj,
487 struct bin_attribute *attr,
488 char *buf, loff_t off, size_t count)
490 struct cmos_rtc *cmos;
491 int retval;
493 cmos = dev_get_drvdata(container_of(kobj, struct device, kobj));
494 if (unlikely(off >= attr->size))
495 return -EFBIG;
496 if (unlikely(off < 0))
497 return -EINVAL;
498 if ((off + count) > attr->size)
499 count = attr->size - off;
501 /* NOTE: on at least PCs and Ataris, the boot firmware uses a
502 * checksum on part of the NVRAM data. That's currently ignored
503 * here. If userspace is smart enough to know what fields of
504 * NVRAM to update, updating checksums is also part of its job.
506 off += NVRAM_OFFSET;
507 spin_lock_irq(&rtc_lock);
508 for (retval = 0; count; count--, off++, retval++) {
509 /* don't trash RTC registers */
510 if (off == cmos->day_alrm
511 || off == cmos->mon_alrm
512 || off == cmos->century)
513 buf++;
514 else if (off < 128)
515 CMOS_WRITE(*buf++, off);
516 else if (can_bank2)
517 cmos_write_bank2(*buf++, off);
518 else
519 break;
521 spin_unlock_irq(&rtc_lock);
523 return retval;
526 static struct bin_attribute nvram = {
527 .attr = {
528 .name = "nvram",
529 .mode = S_IRUGO | S_IWUSR,
532 .read = cmos_nvram_read,
533 .write = cmos_nvram_write,
534 /* size gets set up later */
537 /*----------------------------------------------------------------*/
539 static struct cmos_rtc cmos_rtc;
541 static irqreturn_t cmos_interrupt(int irq, void *p)
543 u8 irqstat;
544 u8 rtc_control;
546 spin_lock(&rtc_lock);
548 /* When the HPET interrupt handler calls us, the interrupt
549 * status is passed as arg1 instead of the irq number. But
550 * always clear irq status, even when HPET is in the way.
552 * Note that HPET and RTC are almost certainly out of phase,
553 * giving different IRQ status ...
555 irqstat = CMOS_READ(RTC_INTR_FLAGS);
556 rtc_control = CMOS_READ(RTC_CONTROL);
557 if (is_hpet_enabled())
558 irqstat = (unsigned long)irq & 0xF0;
559 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
561 /* All Linux RTC alarms should be treated as if they were oneshot.
562 * Similar code may be needed in system wakeup paths, in case the
563 * alarm woke the system.
565 if (irqstat & RTC_AIE) {
566 rtc_control &= ~RTC_AIE;
567 CMOS_WRITE(rtc_control, RTC_CONTROL);
568 hpet_mask_rtc_irq_bit(RTC_AIE);
570 CMOS_READ(RTC_INTR_FLAGS);
572 spin_unlock(&rtc_lock);
574 if (is_intr(irqstat)) {
575 rtc_update_irq(p, 1, irqstat);
576 return IRQ_HANDLED;
577 } else
578 return IRQ_NONE;
581 #ifdef CONFIG_PNP
582 #define INITSECTION
584 #else
585 #define INITSECTION __init
586 #endif
588 static int INITSECTION
589 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
591 struct cmos_rtc_board_info *info = dev->platform_data;
592 int retval = 0;
593 unsigned char rtc_control;
594 unsigned address_space;
596 /* there can be only one ... */
597 if (cmos_rtc.dev)
598 return -EBUSY;
600 if (!ports)
601 return -ENODEV;
603 /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
605 * REVISIT non-x86 systems may instead use memory space resources
606 * (needing ioremap etc), not i/o space resources like this ...
608 ports = request_region(ports->start,
609 resource_size(ports),
610 driver_name);
611 if (!ports) {
612 dev_dbg(dev, "i/o registers already in use\n");
613 return -EBUSY;
616 cmos_rtc.irq = rtc_irq;
617 cmos_rtc.iomem = ports;
619 /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
620 * driver did, but don't reject unknown configs. Old hardware
621 * won't address 128 bytes. Newer chips have multiple banks,
622 * though they may not be listed in one I/O resource.
624 #if defined(CONFIG_ATARI)
625 address_space = 64;
626 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
627 || defined(__sparc__) || defined(__mips__) \
628 || defined(__powerpc__)
629 address_space = 128;
630 #else
631 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
632 address_space = 128;
633 #endif
634 if (can_bank2 && ports->end > (ports->start + 1))
635 address_space = 256;
637 /* For ACPI systems extension info comes from the FADT. On others,
638 * board specific setup provides it as appropriate. Systems where
639 * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
640 * some almost-clones) can provide hooks to make that behave.
642 * Note that ACPI doesn't preclude putting these registers into
643 * "extended" areas of the chip, including some that we won't yet
644 * expect CMOS_READ and friends to handle.
646 if (info) {
647 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
648 cmos_rtc.day_alrm = info->rtc_day_alarm;
649 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
650 cmos_rtc.mon_alrm = info->rtc_mon_alarm;
651 if (info->rtc_century && info->rtc_century < 128)
652 cmos_rtc.century = info->rtc_century;
654 if (info->wake_on && info->wake_off) {
655 cmos_rtc.wake_on = info->wake_on;
656 cmos_rtc.wake_off = info->wake_off;
660 cmos_rtc.dev = dev;
661 dev_set_drvdata(dev, &cmos_rtc);
663 cmos_rtc.rtc = rtc_device_register(driver_name, dev,
664 &cmos_rtc_ops, THIS_MODULE);
665 if (IS_ERR(cmos_rtc.rtc)) {
666 retval = PTR_ERR(cmos_rtc.rtc);
667 goto cleanup0;
670 rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
672 spin_lock_irq(&rtc_lock);
674 /* force periodic irq to CMOS reset default of 1024Hz;
676 * REVISIT it's been reported that at least one x86_64 ALI mobo
677 * doesn't use 32KHz here ... for portability we might need to
678 * do something about other clock frequencies.
680 cmos_rtc.rtc->irq_freq = 1024;
681 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
682 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
684 /* disable irqs */
685 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
687 rtc_control = CMOS_READ(RTC_CONTROL);
689 spin_unlock_irq(&rtc_lock);
691 /* FIXME:
692 * <asm-generic/rtc.h> doesn't know 12-hour mode either.
694 if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
695 dev_warn(dev, "only 24-hr supported\n");
696 retval = -ENXIO;
697 goto cleanup1;
700 if (is_valid_irq(rtc_irq)) {
701 irq_handler_t rtc_cmos_int_handler;
703 if (is_hpet_enabled()) {
704 int err;
706 rtc_cmos_int_handler = hpet_rtc_interrupt;
707 err = hpet_register_irq_handler(cmos_interrupt);
708 if (err != 0) {
709 printk(KERN_WARNING "hpet_register_irq_handler "
710 " failed in rtc_init().");
711 goto cleanup1;
713 } else
714 rtc_cmos_int_handler = cmos_interrupt;
716 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
717 IRQF_DISABLED, dev_name(&cmos_rtc.rtc->dev),
718 cmos_rtc.rtc);
719 if (retval < 0) {
720 dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
721 goto cleanup1;
724 hpet_rtc_timer_init();
726 /* export at least the first block of NVRAM */
727 nvram.size = address_space - NVRAM_OFFSET;
728 retval = sysfs_create_bin_file(&dev->kobj, &nvram);
729 if (retval < 0) {
730 dev_dbg(dev, "can't create nvram file? %d\n", retval);
731 goto cleanup2;
734 pr_info("%s: %s%s, %zd bytes nvram%s\n",
735 dev_name(&cmos_rtc.rtc->dev),
736 !is_valid_irq(rtc_irq) ? "no alarms" :
737 cmos_rtc.mon_alrm ? "alarms up to one year" :
738 cmos_rtc.day_alrm ? "alarms up to one month" :
739 "alarms up to one day",
740 cmos_rtc.century ? ", y3k" : "",
741 nvram.size,
742 is_hpet_enabled() ? ", hpet irqs" : "");
744 return 0;
746 cleanup2:
747 if (is_valid_irq(rtc_irq))
748 free_irq(rtc_irq, cmos_rtc.rtc);
749 cleanup1:
750 cmos_rtc.dev = NULL;
751 rtc_device_unregister(cmos_rtc.rtc);
752 cleanup0:
753 release_region(ports->start, resource_size(ports));
754 return retval;
757 static void cmos_do_shutdown(void)
759 spin_lock_irq(&rtc_lock);
760 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
761 spin_unlock_irq(&rtc_lock);
764 static void __exit cmos_do_remove(struct device *dev)
766 struct cmos_rtc *cmos = dev_get_drvdata(dev);
767 struct resource *ports;
769 cmos_do_shutdown();
771 sysfs_remove_bin_file(&dev->kobj, &nvram);
773 if (is_valid_irq(cmos->irq)) {
774 free_irq(cmos->irq, cmos->rtc);
775 hpet_unregister_irq_handler(cmos_interrupt);
778 rtc_device_unregister(cmos->rtc);
779 cmos->rtc = NULL;
781 ports = cmos->iomem;
782 release_region(ports->start, resource_size(ports));
783 cmos->iomem = NULL;
785 cmos->dev = NULL;
786 dev_set_drvdata(dev, NULL);
789 #ifdef CONFIG_PM
791 static int cmos_suspend(struct device *dev)
793 struct cmos_rtc *cmos = dev_get_drvdata(dev);
794 unsigned char tmp;
796 /* only the alarm might be a wakeup event source */
797 spin_lock_irq(&rtc_lock);
798 cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
799 if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
800 unsigned char mask;
802 if (device_may_wakeup(dev))
803 mask = RTC_IRQMASK & ~RTC_AIE;
804 else
805 mask = RTC_IRQMASK;
806 tmp &= ~mask;
807 CMOS_WRITE(tmp, RTC_CONTROL);
809 /* shut down hpet emulation - we don't need it for alarm */
810 hpet_mask_rtc_irq_bit(RTC_PIE|RTC_AIE|RTC_UIE);
811 cmos_checkintr(cmos, tmp);
813 spin_unlock_irq(&rtc_lock);
815 if (tmp & RTC_AIE) {
816 cmos->enabled_wake = 1;
817 if (cmos->wake_on)
818 cmos->wake_on(dev);
819 else
820 enable_irq_wake(cmos->irq);
823 pr_debug("%s: suspend%s, ctrl %02x\n",
824 dev_name(&cmos_rtc.rtc->dev),
825 (tmp & RTC_AIE) ? ", alarm may wake" : "",
826 tmp);
828 return 0;
831 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
832 * after a detour through G3 "mechanical off", although the ACPI spec
833 * says wakeup should only work from G1/S4 "hibernate". To most users,
834 * distinctions between S4 and S5 are pointless. So when the hardware
835 * allows, don't draw that distinction.
837 static inline int cmos_poweroff(struct device *dev)
839 return cmos_suspend(dev);
842 static int cmos_resume(struct device *dev)
844 struct cmos_rtc *cmos = dev_get_drvdata(dev);
845 unsigned char tmp = cmos->suspend_ctrl;
847 /* re-enable any irqs previously active */
848 if (tmp & RTC_IRQMASK) {
849 unsigned char mask;
851 if (cmos->enabled_wake) {
852 if (cmos->wake_off)
853 cmos->wake_off(dev);
854 else
855 disable_irq_wake(cmos->irq);
856 cmos->enabled_wake = 0;
859 spin_lock_irq(&rtc_lock);
860 do {
861 CMOS_WRITE(tmp, RTC_CONTROL);
862 hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
864 mask = CMOS_READ(RTC_INTR_FLAGS);
865 mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
866 if (!is_hpet_enabled() || !is_intr(mask))
867 break;
869 /* force one-shot behavior if HPET blocked
870 * the wake alarm's irq
872 rtc_update_irq(cmos->rtc, 1, mask);
873 tmp &= ~RTC_AIE;
874 hpet_mask_rtc_irq_bit(RTC_AIE);
875 } while (mask & RTC_AIE);
876 spin_unlock_irq(&rtc_lock);
879 pr_debug("%s: resume, ctrl %02x\n",
880 dev_name(&cmos_rtc.rtc->dev),
881 tmp);
883 return 0;
886 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
888 #else
890 static inline int cmos_poweroff(struct device *dev)
892 return -ENOSYS;
895 #endif
897 /*----------------------------------------------------------------*/
899 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
900 * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
901 * probably list them in similar PNPBIOS tables; so PNP is more common.
903 * We don't use legacy "poke at the hardware" probing. Ancient PCs that
904 * predate even PNPBIOS should set up platform_bus devices.
907 #ifdef CONFIG_ACPI
909 #include <linux/acpi.h>
911 static u32 rtc_handler(void *context)
913 acpi_clear_event(ACPI_EVENT_RTC);
914 acpi_disable_event(ACPI_EVENT_RTC, 0);
915 return ACPI_INTERRUPT_HANDLED;
918 static inline void rtc_wake_setup(void)
920 acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, NULL);
922 * After the RTC handler is installed, the Fixed_RTC event should
923 * be disabled. Only when the RTC alarm is set will it be enabled.
925 acpi_clear_event(ACPI_EVENT_RTC);
926 acpi_disable_event(ACPI_EVENT_RTC, 0);
929 static void rtc_wake_on(struct device *dev)
931 acpi_clear_event(ACPI_EVENT_RTC);
932 acpi_enable_event(ACPI_EVENT_RTC, 0);
935 static void rtc_wake_off(struct device *dev)
937 acpi_disable_event(ACPI_EVENT_RTC, 0);
940 /* Every ACPI platform has a mc146818 compatible "cmos rtc". Here we find
941 * its device node and pass extra config data. This helps its driver use
942 * capabilities that the now-obsolete mc146818 didn't have, and informs it
943 * that this board's RTC is wakeup-capable (per ACPI spec).
945 static struct cmos_rtc_board_info acpi_rtc_info;
947 static void __devinit
948 cmos_wake_setup(struct device *dev)
950 if (acpi_disabled)
951 return;
953 rtc_wake_setup();
954 acpi_rtc_info.wake_on = rtc_wake_on;
955 acpi_rtc_info.wake_off = rtc_wake_off;
957 /* workaround bug in some ACPI tables */
958 if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
959 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
960 acpi_gbl_FADT.month_alarm);
961 acpi_gbl_FADT.month_alarm = 0;
964 acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
965 acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
966 acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
968 /* NOTE: S4_RTC_WAKE is NOT currently useful to Linux */
969 if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
970 dev_info(dev, "RTC can wake from S4\n");
972 dev->platform_data = &acpi_rtc_info;
974 /* RTC always wakes from S1/S2/S3, and often S4/STD */
975 device_init_wakeup(dev, 1);
978 #else
980 static void __devinit
981 cmos_wake_setup(struct device *dev)
985 #endif
987 #ifdef CONFIG_PNP
989 #include <linux/pnp.h>
991 static int __devinit
992 cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
994 cmos_wake_setup(&pnp->dev);
996 if (pnp_port_start(pnp,0) == 0x70 && !pnp_irq_valid(pnp,0))
997 /* Some machines contain a PNP entry for the RTC, but
998 * don't define the IRQ. It should always be safe to
999 * hardcode it in these cases
1001 return cmos_do_probe(&pnp->dev,
1002 pnp_get_resource(pnp, IORESOURCE_IO, 0), 8);
1003 else
1004 return cmos_do_probe(&pnp->dev,
1005 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1006 pnp_irq(pnp, 0));
1009 static void __exit cmos_pnp_remove(struct pnp_dev *pnp)
1011 cmos_do_remove(&pnp->dev);
1014 #ifdef CONFIG_PM
1016 static int cmos_pnp_suspend(struct pnp_dev *pnp, pm_message_t mesg)
1018 return cmos_suspend(&pnp->dev);
1021 static int cmos_pnp_resume(struct pnp_dev *pnp)
1023 return cmos_resume(&pnp->dev);
1026 #else
1027 #define cmos_pnp_suspend NULL
1028 #define cmos_pnp_resume NULL
1029 #endif
1031 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1033 if (system_state == SYSTEM_POWER_OFF && !cmos_poweroff(&pnp->dev))
1034 return;
1036 cmos_do_shutdown();
1039 static const struct pnp_device_id rtc_ids[] = {
1040 { .id = "PNP0b00", },
1041 { .id = "PNP0b01", },
1042 { .id = "PNP0b02", },
1043 { },
1045 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1047 static struct pnp_driver cmos_pnp_driver = {
1048 .name = (char *) driver_name,
1049 .id_table = rtc_ids,
1050 .probe = cmos_pnp_probe,
1051 .remove = __exit_p(cmos_pnp_remove),
1052 .shutdown = cmos_pnp_shutdown,
1054 /* flag ensures resume() gets called, and stops syslog spam */
1055 .flags = PNP_DRIVER_RES_DO_NOT_CHANGE,
1056 .suspend = cmos_pnp_suspend,
1057 .resume = cmos_pnp_resume,
1060 #endif /* CONFIG_PNP */
1062 #ifdef CONFIG_OF
1063 static const struct of_device_id of_cmos_match[] = {
1065 .compatible = "motorola,mc146818",
1067 { },
1069 MODULE_DEVICE_TABLE(of, of_cmos_match);
1071 static __init void cmos_of_init(struct platform_device *pdev)
1073 struct device_node *node = pdev->dev.of_node;
1074 struct rtc_time time;
1075 int ret;
1076 const __be32 *val;
1078 if (!node)
1079 return;
1081 val = of_get_property(node, "ctrl-reg", NULL);
1082 if (val)
1083 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1085 val = of_get_property(node, "freq-reg", NULL);
1086 if (val)
1087 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1089 get_rtc_time(&time);
1090 ret = rtc_valid_tm(&time);
1091 if (ret) {
1092 struct rtc_time def_time = {
1093 .tm_year = 1,
1094 .tm_mday = 1,
1096 set_rtc_time(&def_time);
1099 #else
1100 static inline void cmos_of_init(struct platform_device *pdev) {}
1101 #define of_cmos_match NULL
1102 #endif
1103 /*----------------------------------------------------------------*/
1105 /* Platform setup should have set up an RTC device, when PNP is
1106 * unavailable ... this could happen even on (older) PCs.
1109 static int __init cmos_platform_probe(struct platform_device *pdev)
1111 cmos_of_init(pdev);
1112 cmos_wake_setup(&pdev->dev);
1113 return cmos_do_probe(&pdev->dev,
1114 platform_get_resource(pdev, IORESOURCE_IO, 0),
1115 platform_get_irq(pdev, 0));
1118 static int __exit cmos_platform_remove(struct platform_device *pdev)
1120 cmos_do_remove(&pdev->dev);
1121 return 0;
1124 static void cmos_platform_shutdown(struct platform_device *pdev)
1126 if (system_state == SYSTEM_POWER_OFF && !cmos_poweroff(&pdev->dev))
1127 return;
1129 cmos_do_shutdown();
1132 /* work with hotplug and coldplug */
1133 MODULE_ALIAS("platform:rtc_cmos");
1135 static struct platform_driver cmos_platform_driver = {
1136 .remove = __exit_p(cmos_platform_remove),
1137 .shutdown = cmos_platform_shutdown,
1138 .driver = {
1139 .name = (char *) driver_name,
1140 #ifdef CONFIG_PM
1141 .pm = &cmos_pm_ops,
1142 #endif
1143 .of_match_table = of_cmos_match,
1147 #ifdef CONFIG_PNP
1148 static bool pnp_driver_registered;
1149 #endif
1150 static bool platform_driver_registered;
1152 static int __init cmos_init(void)
1154 int retval = 0;
1156 #ifdef CONFIG_PNP
1157 retval = pnp_register_driver(&cmos_pnp_driver);
1158 if (retval == 0)
1159 pnp_driver_registered = true;
1160 #endif
1162 if (!cmos_rtc.dev) {
1163 retval = platform_driver_probe(&cmos_platform_driver,
1164 cmos_platform_probe);
1165 if (retval == 0)
1166 platform_driver_registered = true;
1169 if (retval == 0)
1170 return 0;
1172 #ifdef CONFIG_PNP
1173 if (pnp_driver_registered)
1174 pnp_unregister_driver(&cmos_pnp_driver);
1175 #endif
1176 return retval;
1178 module_init(cmos_init);
1180 static void __exit cmos_exit(void)
1182 #ifdef CONFIG_PNP
1183 if (pnp_driver_registered)
1184 pnp_unregister_driver(&cmos_pnp_driver);
1185 #endif
1186 if (platform_driver_registered)
1187 platform_driver_unregister(&cmos_platform_driver);
1189 module_exit(cmos_exit);
1192 MODULE_AUTHOR("David Brownell");
1193 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1194 MODULE_LICENSE("GPL");