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         /* REVISIT:  if the clock has a "century" register, use
 198          * that instead of the heuristic in mc146818_get_time().
 199          * That'll make Y3K compatility (year > 2070) easy!
 200          */
 201         mc146818_get_time(t);
 202         return 0;
 203 }
 204
 205 static int cmos_set_time(struct device *dev, struct rtc_time *t)
 206 {
 207         /* REVISIT:  set the "century" register if available
 208          *
 209          * NOTE: this ignores the issue whereby updating the seconds
 210          * takes effect exactly 500ms after we write the register.
 211          * (Also queueing and other delays before we get this far.)
 212          */
 213         return mc146818_set_time(t);
 214 }
 215
 216 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 217 {
 218         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 219         unsigned char   rtc_control;
 220
 221         if (!is_valid_irq(cmos->irq))
 222                 return -EIO;
 223
 224         /* Basic alarms only support hour, minute, and seconds fields.
 225          * Some also support day and month, for alarms up to a year in
 226          * the future.
 227          */
 228
 229         spin_lock_irq(&rtc_lock);
 230         t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 231         t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 232         t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 233
 234         if (cmos->day_alrm) {
 235                 /* ignore upper bits on readback per ACPI spec */
 236                 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
 237                 if (!t->time.tm_mday)
 238                         t->time.tm_mday = -1;
 239
 240                 if (cmos->mon_alrm) {
 241                         t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
 242                         if (!t->time.tm_mon)
 243                                 t->time.tm_mon = -1;
 244                 }
 245         }
 246
 247         rtc_control = CMOS_READ(RTC_CONTROL);
 248         spin_unlock_irq(&rtc_lock);
 249
 250         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 251                 if (((unsigned)t->time.tm_sec) < 0x60)
 252                         t->time.tm_sec = bcd2bin(t->time.tm_sec);
 253                 else
 254                         t->time.tm_sec = -1;
 255                 if (((unsigned)t->time.tm_min) < 0x60)
 256                         t->time.tm_min = bcd2bin(t->time.tm_min);
 257                 else
 258                         t->time.tm_min = -1;
 259                 if (((unsigned)t->time.tm_hour) < 0x24)
 260                         t->time.tm_hour = bcd2bin(t->time.tm_hour);
 261                 else
 262                         t->time.tm_hour = -1;
 263
 264                 if (cmos->day_alrm) {
 265                         if (((unsigned)t->time.tm_mday) <= 0x31)
 266                                 t->time.tm_mday = bcd2bin(t->time.tm_mday);
 267                         else
 268                                 t->time.tm_mday = -1;
 269
 270                         if (cmos->mon_alrm) {
 271                                 if (((unsigned)t->time.tm_mon) <= 0x12)
 272                                         t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
 273                                 else
 274                                         t->time.tm_mon = -1;
 275                         }
 276                 }
 277         }
 278
 279         t->enabled = !!(rtc_control & RTC_AIE);
 280         t->pending = 0;
 281
 282         return 0;
 283 }
 284
 285 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
 286 {
 287         unsigned char   rtc_intr;
 288
 289         /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 290          * allegedly some older rtcs need that to handle irqs properly
 291          */
 292         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 293
 294         if (is_hpet_enabled())
 295                 return;
 296
 297         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 298         if (is_intr(rtc_intr))
 299                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 300 }
 301
 302 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
 303 {
 304         unsigned char   rtc_control;
 305
 306         /* flush any pending IRQ status, notably for update irqs,
 307          * before we enable new IRQs
 308          */
 309         rtc_control = CMOS_READ(RTC_CONTROL);
 310         cmos_checkintr(cmos, rtc_control);
 311
 312         rtc_control |= mask;
 313         CMOS_WRITE(rtc_control, RTC_CONTROL);
 314         hpet_set_rtc_irq_bit(mask);
 315
 316         cmos_checkintr(cmos, rtc_control);
 317 }
 318
 319 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 320 {
 321         unsigned char   rtc_control;
 322
 323         rtc_control = CMOS_READ(RTC_CONTROL);
 324         rtc_control &= ~mask;
 325         CMOS_WRITE(rtc_control, RTC_CONTROL);
 326         hpet_mask_rtc_irq_bit(mask);
 327
 328         cmos_checkintr(cmos, rtc_control);
 329 }
 330
 331 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 332 {
 333         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 334         unsigned char mon, mday, hrs, min, sec, rtc_control;
 335
 336         if (!is_valid_irq(cmos->irq))
 337                 return -EIO;
 338
 339         mon = t->time.tm_mon + 1;
 340         mday = t->time.tm_mday;
 341         hrs = t->time.tm_hour;
 342         min = t->time.tm_min;
 343         sec = t->time.tm_sec;
 344
 345         spin_lock_irq(&rtc_lock);
 346         rtc_control = CMOS_READ(RTC_CONTROL);
 347         spin_unlock_irq(&rtc_lock);
 348
 349         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 350                 /* Writing 0xff means "don't care" or "match all".  */
 351                 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
 352                 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 353                 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
 354                 min = (min < 60) ? bin2bcd(min) : 0xff;
 355                 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
 356         }
 357
 358         spin_lock_irq(&rtc_lock);
 359
 360         /* next rtc irq must not be from previous alarm setting */
 361         cmos_irq_disable(cmos, RTC_AIE);
 362
 363         /* update alarm */
 364         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 365         CMOS_WRITE(min, RTC_MINUTES_ALARM);
 366         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 367
 368         /* the system may support an "enhanced" alarm */
 369         if (cmos->day_alrm) {
 370                 CMOS_WRITE(mday, cmos->day_alrm);
 371                 if (cmos->mon_alrm)
 372                         CMOS_WRITE(mon, cmos->mon_alrm);
 373         }
 374
 375         /* FIXME the HPET alarm glue currently ignores day_alrm
 376          * and mon_alrm ...
 377          */
 378         hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
 379
 380         if (t->enabled)
 381                 cmos_irq_enable(cmos, RTC_AIE);
 382
 383         spin_unlock_irq(&rtc_lock);
 384
 385         cmos->alarm_expires = rtc_tm_to_time64(&t->time);
 386
 387         return 0;
 388 }
 389
 390 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 391 {
 392         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 393         unsigned long   flags;
 394
 395         if (!is_valid_irq(cmos->irq))
 396                 return -EINVAL;
 397
 398         spin_lock_irqsave(&rtc_lock, flags);
 399
 400         if (enabled)
 401                 cmos_irq_enable(cmos, RTC_AIE);
 402         else
 403                 cmos_irq_disable(cmos, RTC_AIE);
 404
 405         spin_unlock_irqrestore(&rtc_lock, flags);
 406         return 0;
 407 }
 408
 409 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 410
 411 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 412 {
 413         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 414         unsigned char   rtc_control, valid;
 415
 416         spin_lock_irq(&rtc_lock);
 417         rtc_control = CMOS_READ(RTC_CONTROL);
 418         valid = CMOS_READ(RTC_VALID);
 419         spin_unlock_irq(&rtc_lock);
 420
 421         /* NOTE:  at least ICH6 reports battery status using a different
 422          * (non-RTC) bit; and SQWE is ignored on many current systems.
 423          */
 424         seq_printf(seq,
 425                    "periodic_IRQ\t: %s\n"
 426                    "update_IRQ\t: %s\n"
 427                    "HPET_emulated\t: %s\n"
 428                    // "square_wave\t: %s\n"
 429                    "BCD\t\t: %s\n"
 430                    "DST_enable\t: %s\n"
 431                    "periodic_freq\t: %d\n"
 432                    "batt_status\t: %s\n",
 433                    (rtc_control & RTC_PIE) ? "yes" : "no",
 434                    (rtc_control & RTC_UIE) ? "yes" : "no",
 435                    is_hpet_enabled() ? "yes" : "no",
 436                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
 437                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 438                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
 439                    cmos->rtc->irq_freq,
 440                    (valid & RTC_VRT) ? "okay" : "dead");
 441
 442         return 0;
 443 }
 444
 445 #else
 446 #define cmos_procfs     NULL
 447 #endif
 448
 449 static const struct rtc_class_ops cmos_rtc_ops = {
 450         .read_time              = cmos_read_time,
 451         .set_time               = cmos_set_time,
 452         .read_alarm             = cmos_read_alarm,
 453         .set_alarm              = cmos_set_alarm,
 454         .proc                   = cmos_procfs,
 455         .alarm_irq_enable       = cmos_alarm_irq_enable,
 456 };
 457
 458 /*----------------------------------------------------------------*/
 459
 460 /*
 461  * All these chips have at least 64 bytes of address space, shared by
 462  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 463  * by boot firmware.  Modern chips have 128 or 256 bytes.
 464  */
 465
 466 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 467
 468 static ssize_t
 469 cmos_nvram_read(struct file *filp, struct kobject *kobj,
 470                 struct bin_attribute *attr,
 471                 char *buf, loff_t off, size_t count)
 472 {
 473         int     retval;
 474
 475         off += NVRAM_OFFSET;
 476         spin_lock_irq(&rtc_lock);
 477         for (retval = 0; count; count--, off++, retval++) {
 478                 if (off < 128)
 479                         *buf++ = CMOS_READ(off);
 480                 else if (can_bank2)
 481                         *buf++ = cmos_read_bank2(off);
 482                 else
 483                         break;
 484         }
 485         spin_unlock_irq(&rtc_lock);
 486
 487         return retval;
 488 }
 489
 490 static ssize_t
 491 cmos_nvram_write(struct file *filp, struct kobject *kobj,
 492                 struct bin_attribute *attr,
 493                 char *buf, loff_t off, size_t count)
 494 {
 495         struct cmos_rtc *cmos;
 496         int             retval;
 497
 498         cmos = dev_get_drvdata(container_of(kobj, struct device, kobj));
 499
 500         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 501          * checksum on part of the NVRAM data.  That's currently ignored
 502          * here.  If userspace is smart enough to know what fields of
 503          * NVRAM to update, updating checksums is also part of its job.
 504          */
 505         off += NVRAM_OFFSET;
 506         spin_lock_irq(&rtc_lock);
 507         for (retval = 0; count; count--, off++, retval++) {
 508                 /* don't trash RTC registers */
 509                 if (off == cmos->day_alrm
 510                                 || off == cmos->mon_alrm
 511                                 || off == cmos->century)
 512                         buf++;
 513                 else if (off < 128)
 514                         CMOS_WRITE(*buf++, off);
 515                 else if (can_bank2)
 516                         cmos_write_bank2(*buf++, off);
 517                 else
 518                         break;
 519         }
 520         spin_unlock_irq(&rtc_lock);
 521
 522         return retval;
 523 }
 524
 525 static struct bin_attribute nvram = {
 526         .attr = {
 527                 .name   = "nvram",
 528                 .mode   = S_IRUGO | S_IWUSR,
 529         },
 530
 531         .read   = cmos_nvram_read,
 532         .write  = cmos_nvram_write,
 533         /* size gets set up later */
 534 };
 535
 536 /*----------------------------------------------------------------*/
 537
 538 static struct cmos_rtc  cmos_rtc;
 539
 540 static irqreturn_t cmos_interrupt(int irq, void *p)
 541 {
 542         u8              irqstat;
 543         u8              rtc_control;
 544
 545         spin_lock(&rtc_lock);
 546
 547         /* When the HPET interrupt handler calls us, the interrupt
 548          * status is passed as arg1 instead of the irq number.  But
 549          * always clear irq status, even when HPET is in the way.
 550          *
 551          * Note that HPET and RTC are almost certainly out of phase,
 552          * giving different IRQ status ...
 553          */
 554         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 555         rtc_control = CMOS_READ(RTC_CONTROL);
 556         if (is_hpet_enabled())
 557                 irqstat = (unsigned long)irq & 0xF0;
 558
 559         /* If we were suspended, RTC_CONTROL may not be accurate since the
 560          * bios may have cleared it.
 561          */
 562         if (!cmos_rtc.suspend_ctrl)
 563                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 564         else
 565                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 566
 567         /* All Linux RTC alarms should be treated as if they were oneshot.
 568          * Similar code may be needed in system wakeup paths, in case the
 569          * alarm woke the system.
 570          */
 571         if (irqstat & RTC_AIE) {
 572                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 573                 rtc_control &= ~RTC_AIE;
 574                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 575                 hpet_mask_rtc_irq_bit(RTC_AIE);
 576                 CMOS_READ(RTC_INTR_FLAGS);
 577         }
 578         spin_unlock(&rtc_lock);
 579
 580         if (is_intr(irqstat)) {
 581                 rtc_update_irq(p, 1, irqstat);
 582                 return IRQ_HANDLED;
 583         } else
 584                 return IRQ_NONE;
 585 }
 586
 587 #ifdef  CONFIG_PNP
 588 #define INITSECTION
 589
 590 #else
 591 #define INITSECTION     __init
 592 #endif
 593
 594 static int INITSECTION
 595 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 596 {
 597         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 598         int                             retval = 0;
 599         unsigned char                   rtc_control;
 600         unsigned                        address_space;
 601         u32                             flags = 0;
 602
 603         /* there can be only one ... */
 604         if (cmos_rtc.dev)
 605                 return -EBUSY;
 606
 607         if (!ports)
 608                 return -ENODEV;
 609
 610         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 611          *
 612          * REVISIT non-x86 systems may instead use memory space resources
 613          * (needing ioremap etc), not i/o space resources like this ...
 614          */
 615         if (RTC_IOMAPPED)
 616                 ports = request_region(ports->start, resource_size(ports),
 617                                        driver_name);
 618         else
 619                 ports = request_mem_region(ports->start, resource_size(ports),
 620                                            driver_name);
 621         if (!ports) {
 622                 dev_dbg(dev, "i/o registers already in use\n");
 623                 return -EBUSY;
 624         }
 625
 626         cmos_rtc.irq = rtc_irq;
 627         cmos_rtc.iomem = ports;
 628
 629         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 630          * driver did, but don't reject unknown configs.   Old hardware
 631          * won't address 128 bytes.  Newer chips have multiple banks,
 632          * though they may not be listed in one I/O resource.
 633          */
 634 #if     defined(CONFIG_ATARI)
 635         address_space = 64;
 636 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 637                         || defined(__sparc__) || defined(__mips__) \
 638                         || defined(__powerpc__) || defined(CONFIG_MN10300)
 639         address_space = 128;
 640 #else
 641 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 642         address_space = 128;
 643 #endif
 644         if (can_bank2 && ports->end > (ports->start + 1))
 645                 address_space = 256;
 646
 647         /* For ACPI systems extension info comes from the FADT.  On others,
 648          * board specific setup provides it as appropriate.  Systems where
 649          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 650          * some almost-clones) can provide hooks to make that behave.
 651          *
 652          * Note that ACPI doesn't preclude putting these registers into
 653          * "extended" areas of the chip, including some that we won't yet
 654          * expect CMOS_READ and friends to handle.
 655          */
 656         if (info) {
 657                 if (info->flags)
 658                         flags = info->flags;
 659                 if (info->address_space)
 660                         address_space = info->address_space;
 661
 662                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 663                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 664                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 665                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 666                 if (info->rtc_century && info->rtc_century < 128)
 667                         cmos_rtc.century = info->rtc_century;
 668
 669                 if (info->wake_on && info->wake_off) {
 670                         cmos_rtc.wake_on = info->wake_on;
 671                         cmos_rtc.wake_off = info->wake_off;
 672                 }
 673         }
 674
 675         cmos_rtc.dev = dev;
 676         dev_set_drvdata(dev, &cmos_rtc);
 677
 678         cmos_rtc.rtc = rtc_device_register(driver_name, dev,
 679                                 &cmos_rtc_ops, THIS_MODULE);
 680         if (IS_ERR(cmos_rtc.rtc)) {
 681                 retval = PTR_ERR(cmos_rtc.rtc);
 682                 goto cleanup0;
 683         }
 684
 685         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 686
 687         spin_lock_irq(&rtc_lock);
 688
 689         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 690                 /* force periodic irq to CMOS reset default of 1024Hz;
 691                  *
 692                  * REVISIT it's been reported that at least one x86_64 ALI
 693                  * mobo doesn't use 32KHz here ... for portability we might
 694                  * need to do something about other clock frequencies.
 695                  */
 696                 cmos_rtc.rtc->irq_freq = 1024;
 697                 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
 698                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 699         }
 700
 701         /* disable irqs */
 702         if (is_valid_irq(rtc_irq))
 703                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 704
 705         rtc_control = CMOS_READ(RTC_CONTROL);
 706
 707         spin_unlock_irq(&rtc_lock);
 708
 709         /* FIXME:
 710          * <asm-generic/rtc.h> doesn't know 12-hour mode either.
 711          */
 712         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
 713                 dev_warn(dev, "only 24-hr supported\n");
 714                 retval = -ENXIO;
 715                 goto cleanup1;
 716         }
 717
 718         hpet_rtc_timer_init();
 719
 720         if (is_valid_irq(rtc_irq)) {
 721                 irq_handler_t rtc_cmos_int_handler;
 722
 723                 if (is_hpet_enabled()) {
 724                         rtc_cmos_int_handler = hpet_rtc_interrupt;
 725                         retval = hpet_register_irq_handler(cmos_interrupt);
 726                         if (retval) {
 727                                 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
 728                                 dev_warn(dev, "hpet_register_irq_handler "
 729                                                 " failed in rtc_init().");
 730                                 goto cleanup1;
 731                         }
 732                 } else
 733                         rtc_cmos_int_handler = cmos_interrupt;
 734
 735                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 736                                 0, dev_name(&cmos_rtc.rtc->dev),
 737                                 cmos_rtc.rtc);
 738                 if (retval < 0) {
 739                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 740                         goto cleanup1;
 741                 }
 742         }
 743
 744         /* export at least the first block of NVRAM */
 745         nvram.size = address_space - NVRAM_OFFSET;
 746         retval = sysfs_create_bin_file(&dev->kobj, &nvram);
 747         if (retval < 0) {
 748                 dev_dbg(dev, "can't create nvram file? %d\n", retval);
 749                 goto cleanup2;
 750         }
 751
 752         dev_info(dev, "%s%s, %zd bytes nvram%s\n",
 753                 !is_valid_irq(rtc_irq) ? "no alarms" :
 754                         cmos_rtc.mon_alrm ? "alarms up to one year" :
 755                         cmos_rtc.day_alrm ? "alarms up to one month" :
 756                         "alarms up to one day",
 757                 cmos_rtc.century ? ", y3k" : "",
 758                 nvram.size,
 759                 is_hpet_enabled() ? ", hpet irqs" : "");
 760
 761         return 0;
 762
 763 cleanup2:
 764         if (is_valid_irq(rtc_irq))
 765                 free_irq(rtc_irq, cmos_rtc.rtc);
 766 cleanup1:
 767         cmos_rtc.dev = NULL;
 768         rtc_device_unregister(cmos_rtc.rtc);
 769 cleanup0:
 770         if (RTC_IOMAPPED)
 771                 release_region(ports->start, resource_size(ports));
 772         else
 773                 release_mem_region(ports->start, resource_size(ports));
 774         return retval;
 775 }
 776
 777 static void cmos_do_shutdown(int rtc_irq)
 778 {
 779         spin_lock_irq(&rtc_lock);
 780         if (is_valid_irq(rtc_irq))
 781                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 782         spin_unlock_irq(&rtc_lock);
 783 }
 784
 785 static void cmos_do_remove(struct device *dev)
 786 {
 787         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 788         struct resource *ports;
 789
 790         cmos_do_shutdown(cmos->irq);
 791
 792         sysfs_remove_bin_file(&dev->kobj, &nvram);
 793
 794         if (is_valid_irq(cmos->irq)) {
 795                 free_irq(cmos->irq, cmos->rtc);
 796                 hpet_unregister_irq_handler(cmos_interrupt);
 797         }
 798
 799         rtc_device_unregister(cmos->rtc);
 800         cmos->rtc = NULL;
 801
 802         ports = cmos->iomem;
 803         if (RTC_IOMAPPED)
 804                 release_region(ports->start, resource_size(ports));
 805         else
 806                 release_mem_region(ports->start, resource_size(ports));
 807         cmos->iomem = NULL;
 808
 809         cmos->dev = NULL;
 810 }
 811
 812 static int cmos_aie_poweroff(struct device *dev)
 813 {
 814         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 815         struct rtc_time now;
 816         time64_t t_now;
 817         int retval = 0;
 818         unsigned char rtc_control;
 819
 820         if (!cmos->alarm_expires)
 821                 return -EINVAL;
 822
 823         spin_lock_irq(&rtc_lock);
 824         rtc_control = CMOS_READ(RTC_CONTROL);
 825         spin_unlock_irq(&rtc_lock);
 826
 827         /* We only care about the situation where AIE is disabled. */
 828         if (rtc_control & RTC_AIE)
 829                 return -EBUSY;
 830
 831         cmos_read_time(dev, &now);
 832         t_now = rtc_tm_to_time64(&now);
 833
 834         /*
 835          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
 836          * automatically right after shutdown on some buggy boxes.
 837          * This automatic rebooting issue won't happen when the alarm
 838          * time is larger than now+1 seconds.
 839          *
 840          * If the alarm time is equal to now+1 seconds, the issue can be
 841          * prevented by cancelling the alarm.
 842          */
 843         if (cmos->alarm_expires == t_now + 1) {
 844                 struct rtc_wkalrm alarm;
 845
 846                 /* Cancel the AIE timer by configuring the past time. */
 847                 rtc_time64_to_tm(t_now - 1, &alarm.time);
 848                 alarm.enabled = 0;
 849                 retval = cmos_set_alarm(dev, &alarm);
 850         } else if (cmos->alarm_expires > t_now + 1) {
 851                 retval = -EBUSY;
 852         }
 853
 854         return retval;
 855 }
 856
 857 static int cmos_suspend(struct device *dev)
 858 {
 859         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 860         unsigned char   tmp;
 861
 862         /* only the alarm might be a wakeup event source */
 863         spin_lock_irq(&rtc_lock);
 864         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 865         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 866                 unsigned char   mask;
 867
 868                 if (device_may_wakeup(dev))
 869                         mask = RTC_IRQMASK & ~RTC_AIE;
 870                 else
 871                         mask = RTC_IRQMASK;
 872                 tmp &= ~mask;
 873                 CMOS_WRITE(tmp, RTC_CONTROL);
 874                 hpet_mask_rtc_irq_bit(mask);
 875
 876                 cmos_checkintr(cmos, tmp);
 877         }
 878         spin_unlock_irq(&rtc_lock);
 879
 880         if (tmp & RTC_AIE) {
 881                 cmos->enabled_wake = 1;
 882                 if (cmos->wake_on)
 883                         cmos->wake_on(dev);
 884                 else
 885                         enable_irq_wake(cmos->irq);
 886         }
 887
 888         cmos_read_alarm(dev, &cmos->saved_wkalrm);
 889
 890         dev_dbg(dev, "suspend%s, ctrl %02x\n",
 891                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
 892                         tmp);
 893
 894         return 0;
 895 }
 896
 897 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
 898  * after a detour through G3 "mechanical off", although the ACPI spec
 899  * says wakeup should only work from G1/S4 "hibernate".  To most users,
 900  * distinctions between S4 and S5 are pointless.  So when the hardware
 901  * allows, don't draw that distinction.
 902  */
 903 static inline int cmos_poweroff(struct device *dev)
 904 {
 905         if (!IS_ENABLED(CONFIG_PM))
 906                 return -ENOSYS;
 907
 908         return cmos_suspend(dev);
 909 }
 910
 911 static void cmos_check_wkalrm(struct device *dev)
 912 {
 913         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 914         struct rtc_wkalrm current_alarm;
 915         time64_t t_current_expires;
 916         time64_t t_saved_expires;
 917
 918         cmos_read_alarm(dev, &current_alarm);
 919         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
 920         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
 921         if (t_current_expires != t_saved_expires ||
 922             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
 923                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
 924         }
 925 }
 926
 927 static void cmos_check_acpi_rtc_status(struct device *dev,
 928                                        unsigned char *rtc_control);
 929
 930 static int __maybe_unused cmos_resume(struct device *dev)
 931 {
 932         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 933         unsigned char tmp;
 934
 935         if (cmos->enabled_wake) {
 936                 if (cmos->wake_off)
 937                         cmos->wake_off(dev);
 938                 else
 939                         disable_irq_wake(cmos->irq);
 940                 cmos->enabled_wake = 0;
 941         }
 942
 943         /* The BIOS might have changed the alarm, restore it */
 944         cmos_check_wkalrm(dev);
 945
 946         spin_lock_irq(&rtc_lock);
 947         tmp = cmos->suspend_ctrl;
 948         cmos->suspend_ctrl = 0;
 949         /* re-enable any irqs previously active */
 950         if (tmp & RTC_IRQMASK) {
 951                 unsigned char   mask;
 952
 953                 if (device_may_wakeup(dev))
 954                         hpet_rtc_timer_init();
 955
 956                 do {
 957                         CMOS_WRITE(tmp, RTC_CONTROL);
 958                         hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
 959
 960                         mask = CMOS_READ(RTC_INTR_FLAGS);
 961                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
 962                         if (!is_hpet_enabled() || !is_intr(mask))
 963                                 break;
 964
 965                         /* force one-shot behavior if HPET blocked
 966                          * the wake alarm's irq
 967                          */
 968                         rtc_update_irq(cmos->rtc, 1, mask);
 969                         tmp &= ~RTC_AIE;
 970                         hpet_mask_rtc_irq_bit(RTC_AIE);
 971                 } while (mask & RTC_AIE);
 972
 973                 if (tmp & RTC_AIE)
 974                         cmos_check_acpi_rtc_status(dev, &tmp);
 975         }
 976         spin_unlock_irq(&rtc_lock);
 977
 978         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
 979
 980         return 0;
 981 }
 982
 983 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
 984
 985 /*----------------------------------------------------------------*/
 986
 987 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
 988  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
 989  * probably list them in similar PNPBIOS tables; so PNP is more common.
 990  *
 991  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
 992  * predate even PNPBIOS should set up platform_bus devices.
 993  */
 994
 995 #ifdef  CONFIG_ACPI
 996
 997 #include <linux/acpi.h>
 998
 999 static u32 rtc_handler(void *context)
1000 {
1001         struct device *dev = context;
1002         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1003         unsigned char rtc_control = 0;
1004         unsigned char rtc_intr;
1005         unsigned long flags;
1006
1007         spin_lock_irqsave(&rtc_lock, flags);
1008         if (cmos_rtc.suspend_ctrl)
1009                 rtc_control = CMOS_READ(RTC_CONTROL);
1010         if (rtc_control & RTC_AIE) {
1011                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1012                 CMOS_WRITE(rtc_control, RTC_CONTROL);
1013                 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1014                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
1015         }
1016         spin_unlock_irqrestore(&rtc_lock, flags);
1017
1018         pm_wakeup_event(dev, 0);
1019         acpi_clear_event(ACPI_EVENT_RTC);
1020         acpi_disable_event(ACPI_EVENT_RTC, 0);
1021         return ACPI_INTERRUPT_HANDLED;
1022 }
1023
1024 static inline void rtc_wake_setup(struct device *dev)
1025 {
1026         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1027         /*
1028          * After the RTC handler is installed, the Fixed_RTC event should
1029          * be disabled. Only when the RTC alarm is set will it be enabled.
1030          */
1031         acpi_clear_event(ACPI_EVENT_RTC);
1032         acpi_disable_event(ACPI_EVENT_RTC, 0);
1033 }
1034
1035 static void rtc_wake_on(struct device *dev)
1036 {
1037         acpi_clear_event(ACPI_EVENT_RTC);
1038         acpi_enable_event(ACPI_EVENT_RTC, 0);
1039 }
1040
1041 static void rtc_wake_off(struct device *dev)
1042 {
1043         acpi_disable_event(ACPI_EVENT_RTC, 0);
1044 }
1045
1046 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1047  * its device node and pass extra config data.  This helps its driver use
1048  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1049  * that this board's RTC is wakeup-capable (per ACPI spec).
1050  */
1051 static struct cmos_rtc_board_info acpi_rtc_info;
1052
1053 static void cmos_wake_setup(struct device *dev)
1054 {
1055         if (acpi_disabled)
1056                 return;
1057
1058         rtc_wake_setup(dev);
1059         acpi_rtc_info.wake_on = rtc_wake_on;
1060         acpi_rtc_info.wake_off = rtc_wake_off;
1061
1062         /* workaround bug in some ACPI tables */
1063         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1064                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1065                         acpi_gbl_FADT.month_alarm);
1066                 acpi_gbl_FADT.month_alarm = 0;
1067         }
1068
1069         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1070         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1071         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1072
1073         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1074         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1075                 dev_info(dev, "RTC can wake from S4\n");
1076
1077         dev->platform_data = &acpi_rtc_info;
1078
1079         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1080         device_init_wakeup(dev, 1);
1081 }
1082
1083 static void cmos_check_acpi_rtc_status(struct device *dev,
1084                                        unsigned char *rtc_control)
1085 {
1086         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1087         acpi_event_status rtc_status;
1088         acpi_status status;
1089
1090         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1091                 return;
1092
1093         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1094         if (ACPI_FAILURE(status)) {
1095                 dev_err(dev, "Could not get RTC status\n");
1096         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1097                 unsigned char mask;
1098                 *rtc_control &= ~RTC_AIE;
1099                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1100                 mask = CMOS_READ(RTC_INTR_FLAGS);
1101                 rtc_update_irq(cmos->rtc, 1, mask);
1102         }
1103 }
1104
1105 #else
1106
1107 static void cmos_wake_setup(struct device *dev)
1108 {
1109 }
1110
1111 static void cmos_check_acpi_rtc_status(struct device *dev,
1112                                        unsigned char *rtc_control)
1113 {
1114 }
1115
1116 #endif
1117
1118 #ifdef  CONFIG_PNP
1119
1120 #include <linux/pnp.h>
1121
1122 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1123 {
1124         cmos_wake_setup(&pnp->dev);
1125
1126         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1127                 unsigned int irq = 0;
1128 #ifdef CONFIG_X86
1129                 /* Some machines contain a PNP entry for the RTC, but
1130                  * don't define the IRQ. It should always be safe to
1131                  * hardcode it on systems with a legacy PIC.
1132                  */
1133                 if (nr_legacy_irqs())
1134                         irq = 8;
1135 #endif
1136                 return cmos_do_probe(&pnp->dev,
1137                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1138         } else {
1139                 return cmos_do_probe(&pnp->dev,
1140                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1141                                 pnp_irq(pnp, 0));
1142         }
1143 }
1144
1145 static void cmos_pnp_remove(struct pnp_dev *pnp)
1146 {
1147         cmos_do_remove(&pnp->dev);
1148 }
1149
1150 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1151 {
1152         struct device *dev = &pnp->dev;
1153         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1154
1155         if (system_state == SYSTEM_POWER_OFF) {
1156                 int retval = cmos_poweroff(dev);
1157
1158                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1159                         return;
1160         }
1161
1162         cmos_do_shutdown(cmos->irq);
1163 }
1164
1165 static const struct pnp_device_id rtc_ids[] = {
1166         { .id = "PNP0b00", },
1167         { .id = "PNP0b01", },
1168         { .id = "PNP0b02", },
1169         { },
1170 };
1171 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1172
1173 static struct pnp_driver cmos_pnp_driver = {
1174         .name           = (char *) driver_name,
1175         .id_table       = rtc_ids,
1176         .probe          = cmos_pnp_probe,
1177         .remove         = cmos_pnp_remove,
1178         .shutdown       = cmos_pnp_shutdown,
1179
1180         /* flag ensures resume() gets called, and stops syslog spam */
1181         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1182         .driver         = {
1183                         .pm = &cmos_pm_ops,
1184         },
1185 };
1186
1187 #endif  /* CONFIG_PNP */
1188
1189 #ifdef CONFIG_OF
1190 static const struct of_device_id of_cmos_match[] = {
1191         {
1192                 .compatible = "motorola,mc146818",
1193         },
1194         { },
1195 };
1196 MODULE_DEVICE_TABLE(of, of_cmos_match);
1197
1198 static __init void cmos_of_init(struct platform_device *pdev)
1199 {
1200         struct device_node *node = pdev->dev.of_node;
1201         struct rtc_time time;
1202         int ret;
1203         const __be32 *val;
1204
1205         if (!node)
1206                 return;
1207
1208         val = of_get_property(node, "ctrl-reg", NULL);
1209         if (val)
1210                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1211
1212         val = of_get_property(node, "freq-reg", NULL);
1213         if (val)
1214                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1215
1216         cmos_read_time(&pdev->dev, &time);
1217         ret = rtc_valid_tm(&time);
1218         if (ret) {
1219                 struct rtc_time def_time = {
1220                         .tm_year = 1,
1221                         .tm_mday = 1,
1222                 };
1223                 cmos_set_time(&pdev->dev, &def_time);
1224         }
1225 }
1226 #else
1227 static inline void cmos_of_init(struct platform_device *pdev) {}
1228 #endif
1229 /*----------------------------------------------------------------*/
1230
1231 /* Platform setup should have set up an RTC device, when PNP is
1232  * unavailable ... this could happen even on (older) PCs.
1233  */
1234
1235 static int __init cmos_platform_probe(struct platform_device *pdev)
1236 {
1237         struct resource *resource;
1238         int irq;
1239
1240         cmos_of_init(pdev);
1241         cmos_wake_setup(&pdev->dev);
1242
1243         if (RTC_IOMAPPED)
1244                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1245         else
1246                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1247         irq = platform_get_irq(pdev, 0);
1248         if (irq < 0)
1249                 irq = -1;
1250
1251         return cmos_do_probe(&pdev->dev, resource, irq);
1252 }
1253
1254 static int cmos_platform_remove(struct platform_device *pdev)
1255 {
1256         cmos_do_remove(&pdev->dev);
1257         return 0;
1258 }
1259
1260 static void cmos_platform_shutdown(struct platform_device *pdev)
1261 {
1262         struct device *dev = &pdev->dev;
1263         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1264
1265         if (system_state == SYSTEM_POWER_OFF) {
1266                 int retval = cmos_poweroff(dev);
1267
1268                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1269                         return;
1270         }
1271
1272         cmos_do_shutdown(cmos->irq);
1273 }
1274
1275 /* work with hotplug and coldplug */
1276 MODULE_ALIAS("platform:rtc_cmos");
1277
1278 static struct platform_driver cmos_platform_driver = {
1279         .remove         = cmos_platform_remove,
1280         .shutdown       = cmos_platform_shutdown,
1281         .driver = {
1282                 .name           = driver_name,
1283                 .pm             = &cmos_pm_ops,
1284                 .of_match_table = of_match_ptr(of_cmos_match),
1285         }
1286 };
1287
1288 #ifdef CONFIG_PNP
1289 static bool pnp_driver_registered;
1290 #endif
1291 static bool platform_driver_registered;
1292
1293 static int __init cmos_init(void)
1294 {
1295         int retval = 0;
1296
1297 #ifdef  CONFIG_PNP
1298         retval = pnp_register_driver(&cmos_pnp_driver);
1299         if (retval == 0)
1300                 pnp_driver_registered = true;
1301 #endif
1302
1303         if (!cmos_rtc.dev) {
1304                 retval = platform_driver_probe(&cmos_platform_driver,
1305                                                cmos_platform_probe);
1306                 if (retval == 0)
1307                         platform_driver_registered = true;
1308         }
1309
1310         if (retval == 0)
1311                 return 0;
1312
1313 #ifdef  CONFIG_PNP
1314         if (pnp_driver_registered)
1315                 pnp_unregister_driver(&cmos_pnp_driver);
1316 #endif
1317         return retval;
1318 }
1319 module_init(cmos_init);
1320
1321 static void __exit cmos_exit(void)
1322 {
1323 #ifdef  CONFIG_PNP
1324         if (pnp_driver_registered)
1325                 pnp_unregister_driver(&cmos_pnp_driver);
1326 #endif
1327         if (platform_driver_registered)
1328                 platform_driver_unregister(&cmos_platform_driver);
1329 }
1330 module_exit(cmos_exit);
1331
1332
1333 MODULE_AUTHOR("David Brownell");
1334 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1335 MODULE_LICENSE("GPL");