Merge tag 'rtc-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux
[muen/linux.git] / drivers / rtc / rtc-cmos.c
1 /*
2  * RTC class driver for "CMOS RTC":  PCs, ACPI, etc
3  *
4  * Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c)
5  * Copyright (C) 2006 David Brownell (convert to new framework)
6  *
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.
11  */
12
13 /*
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.
20  *
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).
26  *
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.
30  */
31
32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33
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>
41 #include <linux/pm.h>
42 #include <linux/of.h>
43 #include <linux/of_platform.h>
44 #ifdef CONFIG_X86
45 #include <asm/i8259.h>
46 #endif
47
48 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
49 #include <linux/mc146818rtc.h>
50
51 struct cmos_rtc {
52         struct rtc_device       *rtc;
53         struct device           *dev;
54         int                     irq;
55         struct resource         *iomem;
56         time64_t                alarm_expires;
57
58         void                    (*wake_on)(struct device *);
59         void                    (*wake_off)(struct device *);
60
61         u8                      enabled_wake;
62         u8                      suspend_ctrl;
63
64         /* newer hardware extends the original register set */
65         u8                      day_alrm;
66         u8                      mon_alrm;
67         u8                      century;
68
69         struct rtc_wkalrm       saved_wkalrm;
70 };
71
72 /* both platform and pnp busses use negative numbers for invalid irqs */
73 #define is_valid_irq(n)         ((n) > 0)
74
75 static const char driver_name[] = "rtc_cmos";
76
77 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
78  * always mask it against the irq enable bits in RTC_CONTROL.  Bit values
79  * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
80  */
81 #define RTC_IRQMASK     (RTC_PF | RTC_AF | RTC_UF)
82
83 static inline int is_intr(u8 rtc_intr)
84 {
85         if (!(rtc_intr & RTC_IRQF))
86                 return 0;
87         return rtc_intr & RTC_IRQMASK;
88 }
89
90 /*----------------------------------------------------------------*/
91
92 /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
93  * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
94  * used in a broken "legacy replacement" mode.  The breakage includes
95  * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
96  * other (better) use.
97  *
98  * When that broken mode is in use, platform glue provides a partial
99  * emulation of hardware RTC IRQ facilities using HPET #1.  We don't
100  * want to use HPET for anything except those IRQs though...
101  */
102 #ifdef CONFIG_HPET_EMULATE_RTC
103 #include <asm/hpet.h>
104 #else
105
106 static inline int is_hpet_enabled(void)
107 {
108         return 0;
109 }
110
111 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
112 {
113         return 0;
114 }
115
116 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
117 {
118         return 0;
119 }
120
121 static inline int
122 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
123 {
124         return 0;
125 }
126
127 static inline int hpet_set_periodic_freq(unsigned long freq)
128 {
129         return 0;
130 }
131
132 static inline int hpet_rtc_dropped_irq(void)
133 {
134         return 0;
135 }
136
137 static inline int hpet_rtc_timer_init(void)
138 {
139         return 0;
140 }
141
142 extern irq_handler_t hpet_rtc_interrupt;
143
144 static inline int hpet_register_irq_handler(irq_handler_t handler)
145 {
146         return 0;
147 }
148
149 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
150 {
151         return 0;
152 }
153
154 #endif
155
156 /*----------------------------------------------------------------*/
157
158 #ifdef RTC_PORT
159
160 /* Most newer x86 systems have two register banks, the first used
161  * for RTC and NVRAM and the second only for NVRAM.  Caller must
162  * own rtc_lock ... and we won't worry about access during NMI.
163  */
164 #define can_bank2       true
165
166 static inline unsigned char cmos_read_bank2(unsigned char addr)
167 {
168         outb(addr, RTC_PORT(2));
169         return inb(RTC_PORT(3));
170 }
171
172 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
173 {
174         outb(addr, RTC_PORT(2));
175         outb(val, RTC_PORT(3));
176 }
177
178 #else
179
180 #define can_bank2       false
181
182 static inline unsigned char cmos_read_bank2(unsigned char addr)
183 {
184         return 0;
185 }
186
187 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
188 {
189 }
190
191 #endif
192
193 /*----------------------------------------------------------------*/
194
195 static int cmos_read_time(struct device *dev, struct rtc_time *t)
196 {
197         /*
198          * If pm_trace abused the RTC for storage, set the timespec to 0,
199          * which tells the caller that this RTC value is unusable.
200          */
201         if (!pm_trace_rtc_valid())
202                 return -EIO;
203
204         /* REVISIT:  if the clock has a "century" register, use
205          * that instead of the heuristic in mc146818_get_time().
206          * That'll make Y3K compatility (year > 2070) easy!
207          */
208         mc146818_get_time(t);
209         return 0;
210 }
211
212 static int cmos_set_time(struct device *dev, struct rtc_time *t)
213 {
214         /* REVISIT:  set the "century" register if available
215          *
216          * NOTE: this ignores the issue whereby updating the seconds
217          * takes effect exactly 500ms after we write the register.
218          * (Also queueing and other delays before we get this far.)
219          */
220         return mc146818_set_time(t);
221 }
222
223 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
224 {
225         struct cmos_rtc *cmos = dev_get_drvdata(dev);
226         unsigned char   rtc_control;
227
228         if (!is_valid_irq(cmos->irq))
229                 return -EIO;
230
231         /* Basic alarms only support hour, minute, and seconds fields.
232          * Some also support day and month, for alarms up to a year in
233          * the future.
234          */
235
236         spin_lock_irq(&rtc_lock);
237         t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
238         t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
239         t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
240
241         if (cmos->day_alrm) {
242                 /* ignore upper bits on readback per ACPI spec */
243                 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
244                 if (!t->time.tm_mday)
245                         t->time.tm_mday = -1;
246
247                 if (cmos->mon_alrm) {
248                         t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
249                         if (!t->time.tm_mon)
250                                 t->time.tm_mon = -1;
251                 }
252         }
253
254         rtc_control = CMOS_READ(RTC_CONTROL);
255         spin_unlock_irq(&rtc_lock);
256
257         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
258                 if (((unsigned)t->time.tm_sec) < 0x60)
259                         t->time.tm_sec = bcd2bin(t->time.tm_sec);
260                 else
261                         t->time.tm_sec = -1;
262                 if (((unsigned)t->time.tm_min) < 0x60)
263                         t->time.tm_min = bcd2bin(t->time.tm_min);
264                 else
265                         t->time.tm_min = -1;
266                 if (((unsigned)t->time.tm_hour) < 0x24)
267                         t->time.tm_hour = bcd2bin(t->time.tm_hour);
268                 else
269                         t->time.tm_hour = -1;
270
271                 if (cmos->day_alrm) {
272                         if (((unsigned)t->time.tm_mday) <= 0x31)
273                                 t->time.tm_mday = bcd2bin(t->time.tm_mday);
274                         else
275                                 t->time.tm_mday = -1;
276
277                         if (cmos->mon_alrm) {
278                                 if (((unsigned)t->time.tm_mon) <= 0x12)
279                                         t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
280                                 else
281                                         t->time.tm_mon = -1;
282                         }
283                 }
284         }
285
286         t->enabled = !!(rtc_control & RTC_AIE);
287         t->pending = 0;
288
289         return 0;
290 }
291
292 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
293 {
294         unsigned char   rtc_intr;
295
296         /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
297          * allegedly some older rtcs need that to handle irqs properly
298          */
299         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
300
301         if (is_hpet_enabled())
302                 return;
303
304         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
305         if (is_intr(rtc_intr))
306                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
307 }
308
309 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
310 {
311         unsigned char   rtc_control;
312
313         /* flush any pending IRQ status, notably for update irqs,
314          * before we enable new IRQs
315          */
316         rtc_control = CMOS_READ(RTC_CONTROL);
317         cmos_checkintr(cmos, rtc_control);
318
319         rtc_control |= mask;
320         CMOS_WRITE(rtc_control, RTC_CONTROL);
321         hpet_set_rtc_irq_bit(mask);
322
323         cmos_checkintr(cmos, rtc_control);
324 }
325
326 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
327 {
328         unsigned char   rtc_control;
329
330         rtc_control = CMOS_READ(RTC_CONTROL);
331         rtc_control &= ~mask;
332         CMOS_WRITE(rtc_control, RTC_CONTROL);
333         hpet_mask_rtc_irq_bit(mask);
334
335         cmos_checkintr(cmos, rtc_control);
336 }
337
338 static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
339 {
340         struct cmos_rtc *cmos = dev_get_drvdata(dev);
341         struct rtc_time now;
342
343         cmos_read_time(dev, &now);
344
345         if (!cmos->day_alrm) {
346                 time64_t t_max_date;
347                 time64_t t_alrm;
348
349                 t_max_date = rtc_tm_to_time64(&now);
350                 t_max_date += 24 * 60 * 60 - 1;
351                 t_alrm = rtc_tm_to_time64(&t->time);
352                 if (t_alrm > t_max_date) {
353                         dev_err(dev,
354                                 "Alarms can be up to one day in the future\n");
355                         return -EINVAL;
356                 }
357         } else if (!cmos->mon_alrm) {
358                 struct rtc_time max_date = now;
359                 time64_t t_max_date;
360                 time64_t t_alrm;
361                 int max_mday;
362
363                 if (max_date.tm_mon == 11) {
364                         max_date.tm_mon = 0;
365                         max_date.tm_year += 1;
366                 } else {
367                         max_date.tm_mon += 1;
368                 }
369                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
370                 if (max_date.tm_mday > max_mday)
371                         max_date.tm_mday = max_mday;
372
373                 t_max_date = rtc_tm_to_time64(&max_date);
374                 t_max_date -= 1;
375                 t_alrm = rtc_tm_to_time64(&t->time);
376                 if (t_alrm > t_max_date) {
377                         dev_err(dev,
378                                 "Alarms can be up to one month in the future\n");
379                         return -EINVAL;
380                 }
381         } else {
382                 struct rtc_time max_date = now;
383                 time64_t t_max_date;
384                 time64_t t_alrm;
385                 int max_mday;
386
387                 max_date.tm_year += 1;
388                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
389                 if (max_date.tm_mday > max_mday)
390                         max_date.tm_mday = max_mday;
391
392                 t_max_date = rtc_tm_to_time64(&max_date);
393                 t_max_date -= 1;
394                 t_alrm = rtc_tm_to_time64(&t->time);
395                 if (t_alrm > t_max_date) {
396                         dev_err(dev,
397                                 "Alarms can be up to one year in the future\n");
398                         return -EINVAL;
399                 }
400         }
401
402         return 0;
403 }
404
405 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
406 {
407         struct cmos_rtc *cmos = dev_get_drvdata(dev);
408         unsigned char mon, mday, hrs, min, sec, rtc_control;
409         int ret;
410
411         if (!is_valid_irq(cmos->irq))
412                 return -EIO;
413
414         ret = cmos_validate_alarm(dev, t);
415         if (ret < 0)
416                 return ret;
417
418         mon = t->time.tm_mon + 1;
419         mday = t->time.tm_mday;
420         hrs = t->time.tm_hour;
421         min = t->time.tm_min;
422         sec = t->time.tm_sec;
423
424         rtc_control = CMOS_READ(RTC_CONTROL);
425         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
426                 /* Writing 0xff means "don't care" or "match all".  */
427                 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
428                 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
429                 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
430                 min = (min < 60) ? bin2bcd(min) : 0xff;
431                 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
432         }
433
434         spin_lock_irq(&rtc_lock);
435
436         /* next rtc irq must not be from previous alarm setting */
437         cmos_irq_disable(cmos, RTC_AIE);
438
439         /* update alarm */
440         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
441         CMOS_WRITE(min, RTC_MINUTES_ALARM);
442         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
443
444         /* the system may support an "enhanced" alarm */
445         if (cmos->day_alrm) {
446                 CMOS_WRITE(mday, cmos->day_alrm);
447                 if (cmos->mon_alrm)
448                         CMOS_WRITE(mon, cmos->mon_alrm);
449         }
450
451         /* FIXME the HPET alarm glue currently ignores day_alrm
452          * and mon_alrm ...
453          */
454         hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
455
456         if (t->enabled)
457                 cmos_irq_enable(cmos, RTC_AIE);
458
459         spin_unlock_irq(&rtc_lock);
460
461         cmos->alarm_expires = rtc_tm_to_time64(&t->time);
462
463         return 0;
464 }
465
466 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
467 {
468         struct cmos_rtc *cmos = dev_get_drvdata(dev);
469         unsigned long   flags;
470
471         if (!is_valid_irq(cmos->irq))
472                 return -EINVAL;
473
474         spin_lock_irqsave(&rtc_lock, flags);
475
476         if (enabled)
477                 cmos_irq_enable(cmos, RTC_AIE);
478         else
479                 cmos_irq_disable(cmos, RTC_AIE);
480
481         spin_unlock_irqrestore(&rtc_lock, flags);
482         return 0;
483 }
484
485 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
486
487 static int cmos_procfs(struct device *dev, struct seq_file *seq)
488 {
489         struct cmos_rtc *cmos = dev_get_drvdata(dev);
490         unsigned char   rtc_control, valid;
491
492         spin_lock_irq(&rtc_lock);
493         rtc_control = CMOS_READ(RTC_CONTROL);
494         valid = CMOS_READ(RTC_VALID);
495         spin_unlock_irq(&rtc_lock);
496
497         /* NOTE:  at least ICH6 reports battery status using a different
498          * (non-RTC) bit; and SQWE is ignored on many current systems.
499          */
500         seq_printf(seq,
501                    "periodic_IRQ\t: %s\n"
502                    "update_IRQ\t: %s\n"
503                    "HPET_emulated\t: %s\n"
504                    // "square_wave\t: %s\n"
505                    "BCD\t\t: %s\n"
506                    "DST_enable\t: %s\n"
507                    "periodic_freq\t: %d\n"
508                    "batt_status\t: %s\n",
509                    (rtc_control & RTC_PIE) ? "yes" : "no",
510                    (rtc_control & RTC_UIE) ? "yes" : "no",
511                    is_hpet_enabled() ? "yes" : "no",
512                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
513                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
514                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
515                    cmos->rtc->irq_freq,
516                    (valid & RTC_VRT) ? "okay" : "dead");
517
518         return 0;
519 }
520
521 #else
522 #define cmos_procfs     NULL
523 #endif
524
525 static const struct rtc_class_ops cmos_rtc_ops = {
526         .read_time              = cmos_read_time,
527         .set_time               = cmos_set_time,
528         .read_alarm             = cmos_read_alarm,
529         .set_alarm              = cmos_set_alarm,
530         .proc                   = cmos_procfs,
531         .alarm_irq_enable       = cmos_alarm_irq_enable,
532 };
533
534 /*----------------------------------------------------------------*/
535
536 /*
537  * All these chips have at least 64 bytes of address space, shared by
538  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
539  * by boot firmware.  Modern chips have 128 or 256 bytes.
540  */
541
542 #define NVRAM_OFFSET    (RTC_REG_D + 1)
543
544 static int cmos_nvram_read(void *priv, unsigned int off, void *val,
545                            size_t count)
546 {
547         unsigned char *buf = val;
548         int     retval;
549
550         off += NVRAM_OFFSET;
551         spin_lock_irq(&rtc_lock);
552         for (retval = 0; count; count--, off++, retval++) {
553                 if (off < 128)
554                         *buf++ = CMOS_READ(off);
555                 else if (can_bank2)
556                         *buf++ = cmos_read_bank2(off);
557                 else
558                         break;
559         }
560         spin_unlock_irq(&rtc_lock);
561
562         return retval;
563 }
564
565 static int cmos_nvram_write(void *priv, unsigned int off, void *val,
566                             size_t count)
567 {
568         struct cmos_rtc *cmos = priv;
569         unsigned char   *buf = val;
570         int             retval;
571
572         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
573          * checksum on part of the NVRAM data.  That's currently ignored
574          * here.  If userspace is smart enough to know what fields of
575          * NVRAM to update, updating checksums is also part of its job.
576          */
577         off += NVRAM_OFFSET;
578         spin_lock_irq(&rtc_lock);
579         for (retval = 0; count; count--, off++, retval++) {
580                 /* don't trash RTC registers */
581                 if (off == cmos->day_alrm
582                                 || off == cmos->mon_alrm
583                                 || off == cmos->century)
584                         buf++;
585                 else if (off < 128)
586                         CMOS_WRITE(*buf++, off);
587                 else if (can_bank2)
588                         cmos_write_bank2(*buf++, off);
589                 else
590                         break;
591         }
592         spin_unlock_irq(&rtc_lock);
593
594         return retval;
595 }
596
597 /*----------------------------------------------------------------*/
598
599 static struct cmos_rtc  cmos_rtc;
600
601 static irqreturn_t cmos_interrupt(int irq, void *p)
602 {
603         u8              irqstat;
604         u8              rtc_control;
605
606         spin_lock(&rtc_lock);
607
608         /* When the HPET interrupt handler calls us, the interrupt
609          * status is passed as arg1 instead of the irq number.  But
610          * always clear irq status, even when HPET is in the way.
611          *
612          * Note that HPET and RTC are almost certainly out of phase,
613          * giving different IRQ status ...
614          */
615         irqstat = CMOS_READ(RTC_INTR_FLAGS);
616         rtc_control = CMOS_READ(RTC_CONTROL);
617         if (is_hpet_enabled())
618                 irqstat = (unsigned long)irq & 0xF0;
619
620         /* If we were suspended, RTC_CONTROL may not be accurate since the
621          * bios may have cleared it.
622          */
623         if (!cmos_rtc.suspend_ctrl)
624                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
625         else
626                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
627
628         /* All Linux RTC alarms should be treated as if they were oneshot.
629          * Similar code may be needed in system wakeup paths, in case the
630          * alarm woke the system.
631          */
632         if (irqstat & RTC_AIE) {
633                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
634                 rtc_control &= ~RTC_AIE;
635                 CMOS_WRITE(rtc_control, RTC_CONTROL);
636                 hpet_mask_rtc_irq_bit(RTC_AIE);
637                 CMOS_READ(RTC_INTR_FLAGS);
638         }
639         spin_unlock(&rtc_lock);
640
641         if (is_intr(irqstat)) {
642                 rtc_update_irq(p, 1, irqstat);
643                 return IRQ_HANDLED;
644         } else
645                 return IRQ_NONE;
646 }
647
648 #ifdef  CONFIG_PNP
649 #define INITSECTION
650
651 #else
652 #define INITSECTION     __init
653 #endif
654
655 static int INITSECTION
656 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
657 {
658         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
659         int                             retval = 0;
660         unsigned char                   rtc_control;
661         unsigned                        address_space;
662         u32                             flags = 0;
663         struct nvmem_config nvmem_cfg = {
664                 .name = "cmos_nvram",
665                 .word_size = 1,
666                 .stride = 1,
667                 .reg_read = cmos_nvram_read,
668                 .reg_write = cmos_nvram_write,
669                 .priv = &cmos_rtc,
670         };
671
672         /* there can be only one ... */
673         if (cmos_rtc.dev)
674                 return -EBUSY;
675
676         if (!ports)
677                 return -ENODEV;
678
679         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
680          *
681          * REVISIT non-x86 systems may instead use memory space resources
682          * (needing ioremap etc), not i/o space resources like this ...
683          */
684         if (RTC_IOMAPPED)
685                 ports = request_region(ports->start, resource_size(ports),
686                                        driver_name);
687         else
688                 ports = request_mem_region(ports->start, resource_size(ports),
689                                            driver_name);
690         if (!ports) {
691                 dev_dbg(dev, "i/o registers already in use\n");
692                 return -EBUSY;
693         }
694
695         cmos_rtc.irq = rtc_irq;
696         cmos_rtc.iomem = ports;
697
698         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
699          * driver did, but don't reject unknown configs.   Old hardware
700          * won't address 128 bytes.  Newer chips have multiple banks,
701          * though they may not be listed in one I/O resource.
702          */
703 #if     defined(CONFIG_ATARI)
704         address_space = 64;
705 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
706                         || defined(__sparc__) || defined(__mips__) \
707                         || defined(__powerpc__)
708         address_space = 128;
709 #else
710 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
711         address_space = 128;
712 #endif
713         if (can_bank2 && ports->end > (ports->start + 1))
714                 address_space = 256;
715
716         /* For ACPI systems extension info comes from the FADT.  On others,
717          * board specific setup provides it as appropriate.  Systems where
718          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
719          * some almost-clones) can provide hooks to make that behave.
720          *
721          * Note that ACPI doesn't preclude putting these registers into
722          * "extended" areas of the chip, including some that we won't yet
723          * expect CMOS_READ and friends to handle.
724          */
725         if (info) {
726                 if (info->flags)
727                         flags = info->flags;
728                 if (info->address_space)
729                         address_space = info->address_space;
730
731                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
732                         cmos_rtc.day_alrm = info->rtc_day_alarm;
733                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
734                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
735                 if (info->rtc_century && info->rtc_century < 128)
736                         cmos_rtc.century = info->rtc_century;
737
738                 if (info->wake_on && info->wake_off) {
739                         cmos_rtc.wake_on = info->wake_on;
740                         cmos_rtc.wake_off = info->wake_off;
741                 }
742         }
743
744         cmos_rtc.dev = dev;
745         dev_set_drvdata(dev, &cmos_rtc);
746
747         cmos_rtc.rtc = devm_rtc_allocate_device(dev);
748         if (IS_ERR(cmos_rtc.rtc)) {
749                 retval = PTR_ERR(cmos_rtc.rtc);
750                 goto cleanup0;
751         }
752
753         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
754
755         spin_lock_irq(&rtc_lock);
756
757         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
758                 /* force periodic irq to CMOS reset default of 1024Hz;
759                  *
760                  * REVISIT it's been reported that at least one x86_64 ALI
761                  * mobo doesn't use 32KHz here ... for portability we might
762                  * need to do something about other clock frequencies.
763                  */
764                 cmos_rtc.rtc->irq_freq = 1024;
765                 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
766                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
767         }
768
769         /* disable irqs */
770         if (is_valid_irq(rtc_irq))
771                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
772
773         rtc_control = CMOS_READ(RTC_CONTROL);
774
775         spin_unlock_irq(&rtc_lock);
776
777         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
778                 dev_warn(dev, "only 24-hr supported\n");
779                 retval = -ENXIO;
780                 goto cleanup1;
781         }
782
783         hpet_rtc_timer_init();
784
785         if (is_valid_irq(rtc_irq)) {
786                 irq_handler_t rtc_cmos_int_handler;
787
788                 if (is_hpet_enabled()) {
789                         rtc_cmos_int_handler = hpet_rtc_interrupt;
790                         retval = hpet_register_irq_handler(cmos_interrupt);
791                         if (retval) {
792                                 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
793                                 dev_warn(dev, "hpet_register_irq_handler "
794                                                 " failed in rtc_init().");
795                                 goto cleanup1;
796                         }
797                 } else
798                         rtc_cmos_int_handler = cmos_interrupt;
799
800                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
801                                 IRQF_SHARED, dev_name(&cmos_rtc.rtc->dev),
802                                 cmos_rtc.rtc);
803                 if (retval < 0) {
804                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
805                         goto cleanup1;
806                 }
807         }
808
809         cmos_rtc.rtc->ops = &cmos_rtc_ops;
810         cmos_rtc.rtc->nvram_old_abi = true;
811         retval = rtc_register_device(cmos_rtc.rtc);
812         if (retval)
813                 goto cleanup2;
814
815         /* export at least the first block of NVRAM */
816         nvmem_cfg.size = address_space - NVRAM_OFFSET;
817         if (rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg))
818                 dev_err(dev, "nvmem registration failed\n");
819
820         dev_info(dev, "%s%s, %d bytes nvram%s\n",
821                  !is_valid_irq(rtc_irq) ? "no alarms" :
822                  cmos_rtc.mon_alrm ? "alarms up to one year" :
823                  cmos_rtc.day_alrm ? "alarms up to one month" :
824                  "alarms up to one day",
825                  cmos_rtc.century ? ", y3k" : "",
826                  nvmem_cfg.size,
827                  is_hpet_enabled() ? ", hpet irqs" : "");
828
829         return 0;
830
831 cleanup2:
832         if (is_valid_irq(rtc_irq))
833                 free_irq(rtc_irq, cmos_rtc.rtc);
834 cleanup1:
835         cmos_rtc.dev = NULL;
836 cleanup0:
837         if (RTC_IOMAPPED)
838                 release_region(ports->start, resource_size(ports));
839         else
840                 release_mem_region(ports->start, resource_size(ports));
841         return retval;
842 }
843
844 static void cmos_do_shutdown(int rtc_irq)
845 {
846         spin_lock_irq(&rtc_lock);
847         if (is_valid_irq(rtc_irq))
848                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
849         spin_unlock_irq(&rtc_lock);
850 }
851
852 static void cmos_do_remove(struct device *dev)
853 {
854         struct cmos_rtc *cmos = dev_get_drvdata(dev);
855         struct resource *ports;
856
857         cmos_do_shutdown(cmos->irq);
858
859         if (is_valid_irq(cmos->irq)) {
860                 free_irq(cmos->irq, cmos->rtc);
861                 hpet_unregister_irq_handler(cmos_interrupt);
862         }
863
864         cmos->rtc = NULL;
865
866         ports = cmos->iomem;
867         if (RTC_IOMAPPED)
868                 release_region(ports->start, resource_size(ports));
869         else
870                 release_mem_region(ports->start, resource_size(ports));
871         cmos->iomem = NULL;
872
873         cmos->dev = NULL;
874 }
875
876 static int cmos_aie_poweroff(struct device *dev)
877 {
878         struct cmos_rtc *cmos = dev_get_drvdata(dev);
879         struct rtc_time now;
880         time64_t t_now;
881         int retval = 0;
882         unsigned char rtc_control;
883
884         if (!cmos->alarm_expires)
885                 return -EINVAL;
886
887         spin_lock_irq(&rtc_lock);
888         rtc_control = CMOS_READ(RTC_CONTROL);
889         spin_unlock_irq(&rtc_lock);
890
891         /* We only care about the situation where AIE is disabled. */
892         if (rtc_control & RTC_AIE)
893                 return -EBUSY;
894
895         cmos_read_time(dev, &now);
896         t_now = rtc_tm_to_time64(&now);
897
898         /*
899          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
900          * automatically right after shutdown on some buggy boxes.
901          * This automatic rebooting issue won't happen when the alarm
902          * time is larger than now+1 seconds.
903          *
904          * If the alarm time is equal to now+1 seconds, the issue can be
905          * prevented by cancelling the alarm.
906          */
907         if (cmos->alarm_expires == t_now + 1) {
908                 struct rtc_wkalrm alarm;
909
910                 /* Cancel the AIE timer by configuring the past time. */
911                 rtc_time64_to_tm(t_now - 1, &alarm.time);
912                 alarm.enabled = 0;
913                 retval = cmos_set_alarm(dev, &alarm);
914         } else if (cmos->alarm_expires > t_now + 1) {
915                 retval = -EBUSY;
916         }
917
918         return retval;
919 }
920
921 static int cmos_suspend(struct device *dev)
922 {
923         struct cmos_rtc *cmos = dev_get_drvdata(dev);
924         unsigned char   tmp;
925
926         /* only the alarm might be a wakeup event source */
927         spin_lock_irq(&rtc_lock);
928         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
929         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
930                 unsigned char   mask;
931
932                 if (device_may_wakeup(dev))
933                         mask = RTC_IRQMASK & ~RTC_AIE;
934                 else
935                         mask = RTC_IRQMASK;
936                 tmp &= ~mask;
937                 CMOS_WRITE(tmp, RTC_CONTROL);
938                 hpet_mask_rtc_irq_bit(mask);
939
940                 cmos_checkintr(cmos, tmp);
941         }
942         spin_unlock_irq(&rtc_lock);
943
944         if (tmp & RTC_AIE) {
945                 cmos->enabled_wake = 1;
946                 if (cmos->wake_on)
947                         cmos->wake_on(dev);
948                 else
949                         enable_irq_wake(cmos->irq);
950         }
951
952         cmos_read_alarm(dev, &cmos->saved_wkalrm);
953
954         dev_dbg(dev, "suspend%s, ctrl %02x\n",
955                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
956                         tmp);
957
958         return 0;
959 }
960
961 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
962  * after a detour through G3 "mechanical off", although the ACPI spec
963  * says wakeup should only work from G1/S4 "hibernate".  To most users,
964  * distinctions between S4 and S5 are pointless.  So when the hardware
965  * allows, don't draw that distinction.
966  */
967 static inline int cmos_poweroff(struct device *dev)
968 {
969         if (!IS_ENABLED(CONFIG_PM))
970                 return -ENOSYS;
971
972         return cmos_suspend(dev);
973 }
974
975 static void cmos_check_wkalrm(struct device *dev)
976 {
977         struct cmos_rtc *cmos = dev_get_drvdata(dev);
978         struct rtc_wkalrm current_alarm;
979         time64_t t_current_expires;
980         time64_t t_saved_expires;
981
982         cmos_read_alarm(dev, &current_alarm);
983         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
984         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
985         if (t_current_expires != t_saved_expires ||
986             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
987                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
988         }
989 }
990
991 static void cmos_check_acpi_rtc_status(struct device *dev,
992                                        unsigned char *rtc_control);
993
994 static int __maybe_unused cmos_resume(struct device *dev)
995 {
996         struct cmos_rtc *cmos = dev_get_drvdata(dev);
997         unsigned char tmp;
998
999         if (cmos->enabled_wake) {
1000                 if (cmos->wake_off)
1001                         cmos->wake_off(dev);
1002                 else
1003                         disable_irq_wake(cmos->irq);
1004                 cmos->enabled_wake = 0;
1005         }
1006
1007         /* The BIOS might have changed the alarm, restore it */
1008         cmos_check_wkalrm(dev);
1009
1010         spin_lock_irq(&rtc_lock);
1011         tmp = cmos->suspend_ctrl;
1012         cmos->suspend_ctrl = 0;
1013         /* re-enable any irqs previously active */
1014         if (tmp & RTC_IRQMASK) {
1015                 unsigned char   mask;
1016
1017                 if (device_may_wakeup(dev))
1018                         hpet_rtc_timer_init();
1019
1020                 do {
1021                         CMOS_WRITE(tmp, RTC_CONTROL);
1022                         hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1023
1024                         mask = CMOS_READ(RTC_INTR_FLAGS);
1025                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1026                         if (!is_hpet_enabled() || !is_intr(mask))
1027                                 break;
1028
1029                         /* force one-shot behavior if HPET blocked
1030                          * the wake alarm's irq
1031                          */
1032                         rtc_update_irq(cmos->rtc, 1, mask);
1033                         tmp &= ~RTC_AIE;
1034                         hpet_mask_rtc_irq_bit(RTC_AIE);
1035                 } while (mask & RTC_AIE);
1036
1037                 if (tmp & RTC_AIE)
1038                         cmos_check_acpi_rtc_status(dev, &tmp);
1039         }
1040         spin_unlock_irq(&rtc_lock);
1041
1042         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1043
1044         return 0;
1045 }
1046
1047 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1048
1049 /*----------------------------------------------------------------*/
1050
1051 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1052  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1053  * probably list them in similar PNPBIOS tables; so PNP is more common.
1054  *
1055  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1056  * predate even PNPBIOS should set up platform_bus devices.
1057  */
1058
1059 #ifdef  CONFIG_ACPI
1060
1061 #include <linux/acpi.h>
1062
1063 static u32 rtc_handler(void *context)
1064 {
1065         struct device *dev = context;
1066         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1067         unsigned char rtc_control = 0;
1068         unsigned char rtc_intr;
1069         unsigned long flags;
1070
1071         spin_lock_irqsave(&rtc_lock, flags);
1072         if (cmos_rtc.suspend_ctrl)
1073                 rtc_control = CMOS_READ(RTC_CONTROL);
1074         if (rtc_control & RTC_AIE) {
1075                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1076                 CMOS_WRITE(rtc_control, RTC_CONTROL);
1077                 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1078                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
1079         }
1080         spin_unlock_irqrestore(&rtc_lock, flags);
1081
1082         pm_wakeup_hard_event(dev);
1083         acpi_clear_event(ACPI_EVENT_RTC);
1084         acpi_disable_event(ACPI_EVENT_RTC, 0);
1085         return ACPI_INTERRUPT_HANDLED;
1086 }
1087
1088 static inline void rtc_wake_setup(struct device *dev)
1089 {
1090         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1091         /*
1092          * After the RTC handler is installed, the Fixed_RTC event should
1093          * be disabled. Only when the RTC alarm is set will it be enabled.
1094          */
1095         acpi_clear_event(ACPI_EVENT_RTC);
1096         acpi_disable_event(ACPI_EVENT_RTC, 0);
1097 }
1098
1099 static void rtc_wake_on(struct device *dev)
1100 {
1101         acpi_clear_event(ACPI_EVENT_RTC);
1102         acpi_enable_event(ACPI_EVENT_RTC, 0);
1103 }
1104
1105 static void rtc_wake_off(struct device *dev)
1106 {
1107         acpi_disable_event(ACPI_EVENT_RTC, 0);
1108 }
1109
1110 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1111  * its device node and pass extra config data.  This helps its driver use
1112  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1113  * that this board's RTC is wakeup-capable (per ACPI spec).
1114  */
1115 static struct cmos_rtc_board_info acpi_rtc_info;
1116
1117 static void cmos_wake_setup(struct device *dev)
1118 {
1119         if (acpi_disabled)
1120                 return;
1121
1122         rtc_wake_setup(dev);
1123         acpi_rtc_info.wake_on = rtc_wake_on;
1124         acpi_rtc_info.wake_off = rtc_wake_off;
1125
1126         /* workaround bug in some ACPI tables */
1127         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1128                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1129                         acpi_gbl_FADT.month_alarm);
1130                 acpi_gbl_FADT.month_alarm = 0;
1131         }
1132
1133         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1134         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1135         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1136
1137         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1138         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1139                 dev_info(dev, "RTC can wake from S4\n");
1140
1141         dev->platform_data = &acpi_rtc_info;
1142
1143         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1144         device_init_wakeup(dev, 1);
1145 }
1146
1147 static void cmos_check_acpi_rtc_status(struct device *dev,
1148                                        unsigned char *rtc_control)
1149 {
1150         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1151         acpi_event_status rtc_status;
1152         acpi_status status;
1153
1154         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1155                 return;
1156
1157         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1158         if (ACPI_FAILURE(status)) {
1159                 dev_err(dev, "Could not get RTC status\n");
1160         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1161                 unsigned char mask;
1162                 *rtc_control &= ~RTC_AIE;
1163                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1164                 mask = CMOS_READ(RTC_INTR_FLAGS);
1165                 rtc_update_irq(cmos->rtc, 1, mask);
1166         }
1167 }
1168
1169 #else
1170
1171 static void cmos_wake_setup(struct device *dev)
1172 {
1173 }
1174
1175 static void cmos_check_acpi_rtc_status(struct device *dev,
1176                                        unsigned char *rtc_control)
1177 {
1178 }
1179
1180 #endif
1181
1182 #ifdef  CONFIG_PNP
1183
1184 #include <linux/pnp.h>
1185
1186 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1187 {
1188         cmos_wake_setup(&pnp->dev);
1189
1190         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1191                 unsigned int irq = 0;
1192 #ifdef CONFIG_X86
1193                 /* Some machines contain a PNP entry for the RTC, but
1194                  * don't define the IRQ. It should always be safe to
1195                  * hardcode it on systems with a legacy PIC.
1196                  */
1197                 if (nr_legacy_irqs())
1198                         irq = 8;
1199 #endif
1200                 return cmos_do_probe(&pnp->dev,
1201                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1202         } else {
1203                 return cmos_do_probe(&pnp->dev,
1204                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1205                                 pnp_irq(pnp, 0));
1206         }
1207 }
1208
1209 static void cmos_pnp_remove(struct pnp_dev *pnp)
1210 {
1211         cmos_do_remove(&pnp->dev);
1212 }
1213
1214 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1215 {
1216         struct device *dev = &pnp->dev;
1217         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1218
1219         if (system_state == SYSTEM_POWER_OFF) {
1220                 int retval = cmos_poweroff(dev);
1221
1222                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1223                         return;
1224         }
1225
1226         cmos_do_shutdown(cmos->irq);
1227 }
1228
1229 static const struct pnp_device_id rtc_ids[] = {
1230         { .id = "PNP0b00", },
1231         { .id = "PNP0b01", },
1232         { .id = "PNP0b02", },
1233         { },
1234 };
1235 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1236
1237 static struct pnp_driver cmos_pnp_driver = {
1238         .name           = (char *) driver_name,
1239         .id_table       = rtc_ids,
1240         .probe          = cmos_pnp_probe,
1241         .remove         = cmos_pnp_remove,
1242         .shutdown       = cmos_pnp_shutdown,
1243
1244         /* flag ensures resume() gets called, and stops syslog spam */
1245         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1246         .driver         = {
1247                         .pm = &cmos_pm_ops,
1248         },
1249 };
1250
1251 #endif  /* CONFIG_PNP */
1252
1253 #ifdef CONFIG_OF
1254 static const struct of_device_id of_cmos_match[] = {
1255         {
1256                 .compatible = "motorola,mc146818",
1257         },
1258         { },
1259 };
1260 MODULE_DEVICE_TABLE(of, of_cmos_match);
1261
1262 static __init void cmos_of_init(struct platform_device *pdev)
1263 {
1264         struct device_node *node = pdev->dev.of_node;
1265         const __be32 *val;
1266
1267         if (!node)
1268                 return;
1269
1270         val = of_get_property(node, "ctrl-reg", NULL);
1271         if (val)
1272                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1273
1274         val = of_get_property(node, "freq-reg", NULL);
1275         if (val)
1276                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1277 }
1278 #else
1279 static inline void cmos_of_init(struct platform_device *pdev) {}
1280 #endif
1281 /*----------------------------------------------------------------*/
1282
1283 /* Platform setup should have set up an RTC device, when PNP is
1284  * unavailable ... this could happen even on (older) PCs.
1285  */
1286
1287 static int __init cmos_platform_probe(struct platform_device *pdev)
1288 {
1289         struct resource *resource;
1290         int irq;
1291
1292         cmos_of_init(pdev);
1293         cmos_wake_setup(&pdev->dev);
1294
1295         if (RTC_IOMAPPED)
1296                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1297         else
1298                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1299         irq = platform_get_irq(pdev, 0);
1300         if (irq < 0)
1301                 irq = -1;
1302
1303         return cmos_do_probe(&pdev->dev, resource, irq);
1304 }
1305
1306 static int cmos_platform_remove(struct platform_device *pdev)
1307 {
1308         cmos_do_remove(&pdev->dev);
1309         return 0;
1310 }
1311
1312 static void cmos_platform_shutdown(struct platform_device *pdev)
1313 {
1314         struct device *dev = &pdev->dev;
1315         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1316
1317         if (system_state == SYSTEM_POWER_OFF) {
1318                 int retval = cmos_poweroff(dev);
1319
1320                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1321                         return;
1322         }
1323
1324         cmos_do_shutdown(cmos->irq);
1325 }
1326
1327 /* work with hotplug and coldplug */
1328 MODULE_ALIAS("platform:rtc_cmos");
1329
1330 static struct platform_driver cmos_platform_driver = {
1331         .remove         = cmos_platform_remove,
1332         .shutdown       = cmos_platform_shutdown,
1333         .driver = {
1334                 .name           = driver_name,
1335                 .pm             = &cmos_pm_ops,
1336                 .of_match_table = of_match_ptr(of_cmos_match),
1337         }
1338 };
1339
1340 #ifdef CONFIG_PNP
1341 static bool pnp_driver_registered;
1342 #endif
1343 static bool platform_driver_registered;
1344
1345 static int __init cmos_init(void)
1346 {
1347         int retval = 0;
1348
1349 #ifdef  CONFIG_PNP
1350         retval = pnp_register_driver(&cmos_pnp_driver);
1351         if (retval == 0)
1352                 pnp_driver_registered = true;
1353 #endif
1354
1355         if (!cmos_rtc.dev) {
1356                 retval = platform_driver_probe(&cmos_platform_driver,
1357                                                cmos_platform_probe);
1358                 if (retval == 0)
1359                         platform_driver_registered = true;
1360         }
1361
1362         if (retval == 0)
1363                 return 0;
1364
1365 #ifdef  CONFIG_PNP
1366         if (pnp_driver_registered)
1367                 pnp_unregister_driver(&cmos_pnp_driver);
1368 #endif
1369         return retval;
1370 }
1371 module_init(cmos_init);
1372
1373 static void __exit cmos_exit(void)
1374 {
1375 #ifdef  CONFIG_PNP
1376         if (pnp_driver_registered)
1377                 pnp_unregister_driver(&cmos_pnp_driver);
1378 #endif
1379         if (platform_driver_registered)
1380                 platform_driver_unregister(&cmos_platform_driver);
1381 }
1382 module_exit(cmos_exit);
1383
1384
1385 MODULE_AUTHOR("David Brownell");
1386 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1387 MODULE_LICENSE("GPL");