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
  45 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
  46 #include <linux/mc146818rtc.h>
  47
  48 struct cmos_rtc {
  49         struct rtc_device       *rtc;
  50         struct device           *dev;
  51         int                     irq;
  52         struct resource         *iomem;
  53         time64_t                alarm_expires;
  54
  55         void                    (*wake_on)(struct device *);
  56         void                    (*wake_off)(struct device *);
  57
  58         u8                      enabled_wake;
  59         u8                      suspend_ctrl;
  60
  61         /* newer hardware extends the original register set */
  62         u8                      day_alrm;
  63         u8                      mon_alrm;
  64         u8                      century;
  65
  66         struct rtc_wkalrm       saved_wkalrm;
  67 };
  68
  69 /* both platform and pnp busses use negative numbers for invalid irqs */
  70 #define is_valid_irq(n)         ((n) > 0)
  71
  72 static const char driver_name[] = "rtc_cmos";
  73
  74 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
  75  * always mask it against the irq enable bits in RTC_CONTROL.  Bit values
  76  * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
  77  */
  78 #define RTC_IRQMASK     (RTC_PF | RTC_AF | RTC_UF)
  79
  80 static inline int is_intr(u8 rtc_intr)
  81 {
  82         if (!(rtc_intr & RTC_IRQF))
  83                 return 0;
  84         return rtc_intr & RTC_IRQMASK;
  85 }
  86
  87 /*----------------------------------------------------------------*/
  88
  89 /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
  90  * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
  91  * used in a broken "legacy replacement" mode.  The breakage includes
  92  * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
  93  * other (better) use.
  94  *
  95  * When that broken mode is in use, platform glue provides a partial
  96  * emulation of hardware RTC IRQ facilities using HPET #1.  We don't
  97  * want to use HPET for anything except those IRQs though...
  98  */
  99 #ifdef CONFIG_HPET_EMULATE_RTC
 100 #include <asm/hpet.h>
 101 #else
 102
 103 static inline int is_hpet_enabled(void)
 104 {
 105         return 0;
 106 }
 107
 108 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
 109 {
 110         return 0;
 111 }
 112
 113 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
 114 {
 115         return 0;
 116 }
 117
 118 static inline int
 119 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
 120 {
 121         return 0;
 122 }
 123
 124 static inline int hpet_set_periodic_freq(unsigned long freq)
 125 {
 126         return 0;
 127 }
 128
 129 static inline int hpet_rtc_dropped_irq(void)
 130 {
 131         return 0;
 132 }
 133
 134 static inline int hpet_rtc_timer_init(void)
 135 {
 136         return 0;
 137 }
 138
 139 extern irq_handler_t hpet_rtc_interrupt;
 140
 141 static inline int hpet_register_irq_handler(irq_handler_t handler)
 142 {
 143         return 0;
 144 }
 145
 146 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
 147 {
 148         return 0;
 149 }
 150
 151 #endif
 152
 153 /*----------------------------------------------------------------*/
 154
 155 #ifdef RTC_PORT
 156
 157 /* Most newer x86 systems have two register banks, the first used
 158  * for RTC and NVRAM and the second only for NVRAM.  Caller must
 159  * own rtc_lock ... and we won't worry about access during NMI.
 160  */
 161 #define can_bank2       true
 162
 163 static inline unsigned char cmos_read_bank2(unsigned char addr)
 164 {
 165         outb(addr, RTC_PORT(2));
 166         return inb(RTC_PORT(3));
 167 }
 168
 169 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 170 {
 171         outb(addr, RTC_PORT(2));
 172         outb(val, RTC_PORT(3));
 173 }
 174
 175 #else
 176
 177 #define can_bank2       false
 178
 179 static inline unsigned char cmos_read_bank2(unsigned char addr)
 180 {
 181         return 0;
 182 }
 183
 184 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 185 {
 186 }
 187
 188 #endif
 189
 190 /*----------------------------------------------------------------*/
 191
 192 static int cmos_read_time(struct device *dev, struct rtc_time *t)
 193 {
 194         /*
 195          * If pm_trace abused the RTC for storage, set the timespec to 0,
 196          * which tells the caller that this RTC value is unusable.
 197          */
 198         if (!pm_trace_rtc_valid())
 199                 return -EIO;
 200
 201         /* REVISIT:  if the clock has a "century" register, use
 202          * that instead of the heuristic in mc146818_get_time().
 203          * That'll make Y3K compatility (year > 2070) easy!
 204          */
 205         mc146818_get_time(t);
 206         return 0;
 207 }
 208
 209 static int cmos_set_time(struct device *dev, struct rtc_time *t)
 210 {
 211         /* REVISIT:  set the "century" register if available
 212          *
 213          * NOTE: this ignores the issue whereby updating the seconds
 214          * takes effect exactly 500ms after we write the register.
 215          * (Also queueing and other delays before we get this far.)
 216          */
 217         return mc146818_set_time(t);
 218 }
 219
 220 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 221 {
 222         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 223         unsigned char   rtc_control;
 224
 225         if (!is_valid_irq(cmos->irq))
 226                 return -EIO;
 227
 228         /* Basic alarms only support hour, minute, and seconds fields.
 229          * Some also support day and month, for alarms up to a year in
 230          * the future.
 231          */
 232
 233         spin_lock_irq(&rtc_lock);
 234         t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 235         t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 236         t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 237
 238         if (cmos->day_alrm) {
 239                 /* ignore upper bits on readback per ACPI spec */
 240                 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
 241                 if (!t->time.tm_mday)
 242                         t->time.tm_mday = -1;
 243
 244                 if (cmos->mon_alrm) {
 245                         t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
 246                         if (!t->time.tm_mon)
 247                                 t->time.tm_mon = -1;
 248                 }
 249         }
 250
 251         rtc_control = CMOS_READ(RTC_CONTROL);
 252         spin_unlock_irq(&rtc_lock);
 253
 254         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 255                 if (((unsigned)t->time.tm_sec) < 0x60)
 256                         t->time.tm_sec = bcd2bin(t->time.tm_sec);
 257                 else
 258                         t->time.tm_sec = -1;
 259                 if (((unsigned)t->time.tm_min) < 0x60)
 260                         t->time.tm_min = bcd2bin(t->time.tm_min);
 261                 else
 262                         t->time.tm_min = -1;
 263                 if (((unsigned)t->time.tm_hour) < 0x24)
 264                         t->time.tm_hour = bcd2bin(t->time.tm_hour);
 265                 else
 266                         t->time.tm_hour = -1;
 267
 268                 if (cmos->day_alrm) {
 269                         if (((unsigned)t->time.tm_mday) <= 0x31)
 270                                 t->time.tm_mday = bcd2bin(t->time.tm_mday);
 271                         else
 272                                 t->time.tm_mday = -1;
 273
 274                         if (cmos->mon_alrm) {
 275                                 if (((unsigned)t->time.tm_mon) <= 0x12)
 276                                         t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
 277                                 else
 278                                         t->time.tm_mon = -1;
 279                         }
 280                 }
 281         }
 282
 283         t->enabled = !!(rtc_control & RTC_AIE);
 284         t->pending = 0;
 285
 286         return 0;
 287 }
 288
 289 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
 290 {
 291         unsigned char   rtc_intr;
 292
 293         /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 294          * allegedly some older rtcs need that to handle irqs properly
 295          */
 296         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 297
 298         if (is_hpet_enabled())
 299                 return;
 300
 301         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 302         if (is_intr(rtc_intr))
 303                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 304 }
 305
 306 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
 307 {
 308         unsigned char   rtc_control;
 309
 310         /* flush any pending IRQ status, notably for update irqs,
 311          * before we enable new IRQs
 312          */
 313         rtc_control = CMOS_READ(RTC_CONTROL);
 314         cmos_checkintr(cmos, rtc_control);
 315
 316         rtc_control |= mask;
 317         CMOS_WRITE(rtc_control, RTC_CONTROL);
 318         hpet_set_rtc_irq_bit(mask);
 319
 320         cmos_checkintr(cmos, rtc_control);
 321 }
 322
 323 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 324 {
 325         unsigned char   rtc_control;
 326
 327         rtc_control = CMOS_READ(RTC_CONTROL);
 328         rtc_control &= ~mask;
 329         CMOS_WRITE(rtc_control, RTC_CONTROL);
 330         hpet_mask_rtc_irq_bit(mask);
 331
 332         cmos_checkintr(cmos, rtc_control);
 333 }
 334
 335 static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
 336 {
 337         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 338         struct rtc_time now;
 339
 340         cmos_read_time(dev, &now);
 341
 342         if (!cmos->day_alrm) {
 343                 time64_t t_max_date;
 344                 time64_t t_alrm;
 345
 346                 t_max_date = rtc_tm_to_time64(&now);
 347                 t_max_date += 24 * 60 * 60 - 1;
 348                 t_alrm = rtc_tm_to_time64(&t->time);
 349                 if (t_alrm > t_max_date) {
 350                         dev_err(dev,
 351                                 "Alarms can be up to one day in the future\n");
 352                         return -EINVAL;
 353                 }
 354         } else if (!cmos->mon_alrm) {
 355                 struct rtc_time max_date = now;
 356                 time64_t t_max_date;
 357                 time64_t t_alrm;
 358                 int max_mday;
 359
 360                 if (max_date.tm_mon == 11) {
 361                         max_date.tm_mon = 0;
 362                         max_date.tm_year += 1;
 363                 } else {
 364                         max_date.tm_mon += 1;
 365                 }
 366                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 367                 if (max_date.tm_mday > max_mday)
 368                         max_date.tm_mday = max_mday;
 369
 370                 t_max_date = rtc_tm_to_time64(&max_date);
 371                 t_max_date -= 1;
 372                 t_alrm = rtc_tm_to_time64(&t->time);
 373                 if (t_alrm > t_max_date) {
 374                         dev_err(dev,
 375                                 "Alarms can be up to one month in the future\n");
 376                         return -EINVAL;
 377                 }
 378         } else {
 379                 struct rtc_time max_date = now;
 380                 time64_t t_max_date;
 381                 time64_t t_alrm;
 382                 int max_mday;
 383
 384                 max_date.tm_year += 1;
 385                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 386                 if (max_date.tm_mday > max_mday)
 387                         max_date.tm_mday = max_mday;
 388
 389                 t_max_date = rtc_tm_to_time64(&max_date);
 390                 t_max_date -= 1;
 391                 t_alrm = rtc_tm_to_time64(&t->time);
 392                 if (t_alrm > t_max_date) {
 393                         dev_err(dev,
 394                                 "Alarms can be up to one year in the future\n");
 395                         return -EINVAL;
 396                 }
 397         }
 398
 399         return 0;
 400 }
 401
 402 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 403 {
 404         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 405         unsigned char mon, mday, hrs, min, sec, rtc_control;
 406         int ret;
 407
 408         if (!is_valid_irq(cmos->irq))
 409                 return -EIO;
 410
 411         ret = cmos_validate_alarm(dev, t);
 412         if (ret < 0)
 413                 return ret;
 414
 415         mon = t->time.tm_mon + 1;
 416         mday = t->time.tm_mday;
 417         hrs = t->time.tm_hour;
 418         min = t->time.tm_min;
 419         sec = t->time.tm_sec;
 420
 421         rtc_control = CMOS_READ(RTC_CONTROL);
 422         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 423                 /* Writing 0xff means "don't care" or "match all".  */
 424                 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
 425                 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 426                 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
 427                 min = (min < 60) ? bin2bcd(min) : 0xff;
 428                 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
 429         }
 430
 431         spin_lock_irq(&rtc_lock);
 432
 433         /* next rtc irq must not be from previous alarm setting */
 434         cmos_irq_disable(cmos, RTC_AIE);
 435
 436         /* update alarm */
 437         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 438         CMOS_WRITE(min, RTC_MINUTES_ALARM);
 439         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 440
 441         /* the system may support an "enhanced" alarm */
 442         if (cmos->day_alrm) {
 443                 CMOS_WRITE(mday, cmos->day_alrm);
 444                 if (cmos->mon_alrm)
 445                         CMOS_WRITE(mon, cmos->mon_alrm);
 446         }
 447
 448         /* FIXME the HPET alarm glue currently ignores day_alrm
 449          * and mon_alrm ...
 450          */
 451         hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
 452
 453         if (t->enabled)
 454                 cmos_irq_enable(cmos, RTC_AIE);
 455
 456         spin_unlock_irq(&rtc_lock);
 457
 458         cmos->alarm_expires = rtc_tm_to_time64(&t->time);
 459
 460         return 0;
 461 }
 462
 463 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 464 {
 465         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 466         unsigned long   flags;
 467
 468         if (!is_valid_irq(cmos->irq))
 469                 return -EINVAL;
 470
 471         spin_lock_irqsave(&rtc_lock, flags);
 472
 473         if (enabled)
 474                 cmos_irq_enable(cmos, RTC_AIE);
 475         else
 476                 cmos_irq_disable(cmos, RTC_AIE);
 477
 478         spin_unlock_irqrestore(&rtc_lock, flags);
 479         return 0;
 480 }
 481
 482 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 483
 484 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 485 {
 486         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 487         unsigned char   rtc_control, valid;
 488
 489         spin_lock_irq(&rtc_lock);
 490         rtc_control = CMOS_READ(RTC_CONTROL);
 491         valid = CMOS_READ(RTC_VALID);
 492         spin_unlock_irq(&rtc_lock);
 493
 494         /* NOTE:  at least ICH6 reports battery status using a different
 495          * (non-RTC) bit; and SQWE is ignored on many current systems.
 496          */
 497         seq_printf(seq,
 498                    "periodic_IRQ\t: %s\n"
 499                    "update_IRQ\t: %s\n"
 500                    "HPET_emulated\t: %s\n"
 501                    // "square_wave\t: %s\n"
 502                    "BCD\t\t: %s\n"
 503                    "DST_enable\t: %s\n"
 504                    "periodic_freq\t: %d\n"
 505                    "batt_status\t: %s\n",
 506                    (rtc_control & RTC_PIE) ? "yes" : "no",
 507                    (rtc_control & RTC_UIE) ? "yes" : "no",
 508                    is_hpet_enabled() ? "yes" : "no",
 509                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
 510                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 511                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
 512                    cmos->rtc->irq_freq,
 513                    (valid & RTC_VRT) ? "okay" : "dead");
 514
 515         return 0;
 516 }
 517
 518 #else
 519 #define cmos_procfs     NULL
 520 #endif
 521
 522 static const struct rtc_class_ops cmos_rtc_ops = {
 523         .read_time              = cmos_read_time,
 524         .set_time               = cmos_set_time,
 525         .read_alarm             = cmos_read_alarm,
 526         .set_alarm              = cmos_set_alarm,
 527         .proc                   = cmos_procfs,
 528         .alarm_irq_enable       = cmos_alarm_irq_enable,
 529 };
 530
 531 /*----------------------------------------------------------------*/
 532
 533 /*
 534  * All these chips have at least 64 bytes of address space, shared by
 535  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 536  * by boot firmware.  Modern chips have 128 or 256 bytes.
 537  */
 538
 539 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 540
 541 static ssize_t
 542 cmos_nvram_read(struct file *filp, struct kobject *kobj,
 543                 struct bin_attribute *attr,
 544                 char *buf, loff_t off, size_t count)
 545 {
 546         int     retval;
 547
 548         off += NVRAM_OFFSET;
 549         spin_lock_irq(&rtc_lock);
 550         for (retval = 0; count; count--, off++, retval++) {
 551                 if (off < 128)
 552                         *buf++ = CMOS_READ(off);
 553                 else if (can_bank2)
 554                         *buf++ = cmos_read_bank2(off);
 555                 else
 556                         break;
 557         }
 558         spin_unlock_irq(&rtc_lock);
 559
 560         return retval;
 561 }
 562
 563 static ssize_t
 564 cmos_nvram_write(struct file *filp, struct kobject *kobj,
 565                 struct bin_attribute *attr,
 566                 char *buf, loff_t off, size_t count)
 567 {
 568         struct cmos_rtc *cmos;
 569         int             retval;
 570
 571         cmos = dev_get_drvdata(container_of(kobj, struct device, kobj));
 572
 573         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 574          * checksum on part of the NVRAM data.  That's currently ignored
 575          * here.  If userspace is smart enough to know what fields of
 576          * NVRAM to update, updating checksums is also part of its job.
 577          */
 578         off += NVRAM_OFFSET;
 579         spin_lock_irq(&rtc_lock);
 580         for (retval = 0; count; count--, off++, retval++) {
 581                 /* don't trash RTC registers */
 582                 if (off == cmos->day_alrm
 583                                 || off == cmos->mon_alrm
 584                                 || off == cmos->century)
 585                         buf++;
 586                 else if (off < 128)
 587                         CMOS_WRITE(*buf++, off);
 588                 else if (can_bank2)
 589                         cmos_write_bank2(*buf++, off);
 590                 else
 591                         break;
 592         }
 593         spin_unlock_irq(&rtc_lock);
 594
 595         return retval;
 596 }
 597
 598 static struct bin_attribute nvram = {
 599         .attr = {
 600                 .name   = "nvram",
 601                 .mode   = S_IRUGO | S_IWUSR,
 602         },
 603
 604         .read   = cmos_nvram_read,
 605         .write  = cmos_nvram_write,
 606         /* size gets set up later */
 607 };
 608
 609 /*----------------------------------------------------------------*/
 610
 611 static struct cmos_rtc  cmos_rtc;
 612
 613 static irqreturn_t cmos_interrupt(int irq, void *p)
 614 {
 615         u8              irqstat;
 616         u8              rtc_control;
 617
 618         spin_lock(&rtc_lock);
 619
 620         /* When the HPET interrupt handler calls us, the interrupt
 621          * status is passed as arg1 instead of the irq number.  But
 622          * always clear irq status, even when HPET is in the way.
 623          *
 624          * Note that HPET and RTC are almost certainly out of phase,
 625          * giving different IRQ status ...
 626          */
 627         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 628         rtc_control = CMOS_READ(RTC_CONTROL);
 629         if (is_hpet_enabled())
 630                 irqstat = (unsigned long)irq & 0xF0;
 631
 632         /* If we were suspended, RTC_CONTROL may not be accurate since the
 633          * bios may have cleared it.
 634          */
 635         if (!cmos_rtc.suspend_ctrl)
 636                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 637         else
 638                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 639
 640         /* All Linux RTC alarms should be treated as if they were oneshot.
 641          * Similar code may be needed in system wakeup paths, in case the
 642          * alarm woke the system.
 643          */
 644         if (irqstat & RTC_AIE) {
 645                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 646                 rtc_control &= ~RTC_AIE;
 647                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 648                 hpet_mask_rtc_irq_bit(RTC_AIE);
 649                 CMOS_READ(RTC_INTR_FLAGS);
 650         }
 651         spin_unlock(&rtc_lock);
 652
 653         if (is_intr(irqstat)) {
 654                 rtc_update_irq(p, 1, irqstat);
 655                 return IRQ_HANDLED;
 656         } else
 657                 return IRQ_NONE;
 658 }
 659
 660 #ifdef  CONFIG_PNP
 661 #define INITSECTION
 662
 663 #else
 664 #define INITSECTION     __init
 665 #endif
 666
 667 static int INITSECTION
 668 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 669 {
 670         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 671         int                             retval = 0;
 672         unsigned char                   rtc_control;
 673         unsigned                        address_space;
 674         u32                             flags = 0;
 675
 676         /* there can be only one ... */
 677         if (cmos_rtc.dev)
 678                 return -EBUSY;
 679
 680         if (!ports)
 681                 return -ENODEV;
 682
 683         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 684          *
 685          * REVISIT non-x86 systems may instead use memory space resources
 686          * (needing ioremap etc), not i/o space resources like this ...
 687          */
 688         if (RTC_IOMAPPED)
 689                 ports = request_region(ports->start, resource_size(ports),
 690                                        driver_name);
 691         else
 692                 ports = request_mem_region(ports->start, resource_size(ports),
 693                                            driver_name);
 694         if (!ports) {
 695                 dev_dbg(dev, "i/o registers already in use\n");
 696                 return -EBUSY;
 697         }
 698
 699         cmos_rtc.irq = rtc_irq;
 700         cmos_rtc.iomem = ports;
 701
 702         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 703          * driver did, but don't reject unknown configs.   Old hardware
 704          * won't address 128 bytes.  Newer chips have multiple banks,
 705          * though they may not be listed in one I/O resource.
 706          */
 707 #if     defined(CONFIG_ATARI)
 708         address_space = 64;
 709 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 710                         || defined(__sparc__) || defined(__mips__) \
 711                         || defined(__powerpc__) || defined(CONFIG_MN10300)
 712         address_space = 128;
 713 #else
 714 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 715         address_space = 128;
 716 #endif
 717         if (can_bank2 && ports->end > (ports->start + 1))
 718                 address_space = 256;
 719
 720         /* For ACPI systems extension info comes from the FADT.  On others,
 721          * board specific setup provides it as appropriate.  Systems where
 722          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 723          * some almost-clones) can provide hooks to make that behave.
 724          *
 725          * Note that ACPI doesn't preclude putting these registers into
 726          * "extended" areas of the chip, including some that we won't yet
 727          * expect CMOS_READ and friends to handle.
 728          */
 729         if (info) {
 730                 if (info->flags)
 731                         flags = info->flags;
 732                 if (info->address_space)
 733                         address_space = info->address_space;
 734
 735                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 736                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 737                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 738                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 739                 if (info->rtc_century && info->rtc_century < 128)
 740                         cmos_rtc.century = info->rtc_century;
 741
 742                 if (info->wake_on && info->wake_off) {
 743                         cmos_rtc.wake_on = info->wake_on;
 744                         cmos_rtc.wake_off = info->wake_off;
 745                 }
 746         }
 747
 748         cmos_rtc.dev = dev;
 749         dev_set_drvdata(dev, &cmos_rtc);
 750
 751         cmos_rtc.rtc = rtc_device_register(driver_name, dev,
 752                                 &cmos_rtc_ops, THIS_MODULE);
 753         if (IS_ERR(cmos_rtc.rtc)) {
 754                 retval = PTR_ERR(cmos_rtc.rtc);
 755                 goto cleanup0;
 756         }
 757
 758         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 759
 760         spin_lock_irq(&rtc_lock);
 761
 762         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 763                 /* force periodic irq to CMOS reset default of 1024Hz;
 764                  *
 765                  * REVISIT it's been reported that at least one x86_64 ALI
 766                  * mobo doesn't use 32KHz here ... for portability we might
 767                  * need to do something about other clock frequencies.
 768                  */
 769                 cmos_rtc.rtc->irq_freq = 1024;
 770                 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
 771                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 772         }
 773
 774         /* disable irqs */
 775         if (is_valid_irq(rtc_irq))
 776                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 777
 778         rtc_control = CMOS_READ(RTC_CONTROL);
 779
 780         spin_unlock_irq(&rtc_lock);
 781
 782         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
 783                 dev_warn(dev, "only 24-hr supported\n");
 784                 retval = -ENXIO;
 785                 goto cleanup1;
 786         }
 787
 788         hpet_rtc_timer_init();
 789
 790         if (is_valid_irq(rtc_irq)) {
 791                 irq_handler_t rtc_cmos_int_handler;
 792
 793                 if (is_hpet_enabled()) {
 794                         rtc_cmos_int_handler = hpet_rtc_interrupt;
 795                         retval = hpet_register_irq_handler(cmos_interrupt);
 796                         if (retval) {
 797                                 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
 798                                 dev_warn(dev, "hpet_register_irq_handler "
 799                                                 " failed in rtc_init().");
 800                                 goto cleanup1;
 801                         }
 802                 } else
 803                         rtc_cmos_int_handler = cmos_interrupt;
 804
 805                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 806                                 IRQF_SHARED, dev_name(&cmos_rtc.rtc->dev),
 807                                 cmos_rtc.rtc);
 808                 if (retval < 0) {
 809                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 810                         goto cleanup1;
 811                 }
 812         }
 813
 814         /* export at least the first block of NVRAM */
 815         nvram.size = address_space - NVRAM_OFFSET;
 816         retval = sysfs_create_bin_file(&dev->kobj, &nvram);
 817         if (retval < 0) {
 818                 dev_dbg(dev, "can't create nvram file? %d\n", retval);
 819                 goto cleanup2;
 820         }
 821
 822         dev_info(dev, "%s%s, %zd bytes nvram%s\n",
 823                 !is_valid_irq(rtc_irq) ? "no alarms" :
 824                         cmos_rtc.mon_alrm ? "alarms up to one year" :
 825                         cmos_rtc.day_alrm ? "alarms up to one month" :
 826                         "alarms up to one day",
 827                 cmos_rtc.century ? ", y3k" : "",
 828                 nvram.size,
 829                 is_hpet_enabled() ? ", hpet irqs" : "");
 830
 831         return 0;
 832
 833 cleanup2:
 834         if (is_valid_irq(rtc_irq))
 835                 free_irq(rtc_irq, cmos_rtc.rtc);
 836 cleanup1:
 837         cmos_rtc.dev = NULL;
 838         rtc_device_unregister(cmos_rtc.rtc);
 839 cleanup0:
 840         if (RTC_IOMAPPED)
 841                 release_region(ports->start, resource_size(ports));
 842         else
 843                 release_mem_region(ports->start, resource_size(ports));
 844         return retval;
 845 }
 846
 847 static void cmos_do_shutdown(int rtc_irq)
 848 {
 849         spin_lock_irq(&rtc_lock);
 850         if (is_valid_irq(rtc_irq))
 851                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 852         spin_unlock_irq(&rtc_lock);
 853 }
 854
 855 static void cmos_do_remove(struct device *dev)
 856 {
 857         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 858         struct resource *ports;
 859
 860         cmos_do_shutdown(cmos->irq);
 861
 862         sysfs_remove_bin_file(&dev->kobj, &nvram);
 863
 864         if (is_valid_irq(cmos->irq)) {
 865                 free_irq(cmos->irq, cmos->rtc);
 866                 hpet_unregister_irq_handler(cmos_interrupt);
 867         }
 868
 869         rtc_device_unregister(cmos->rtc);
 870         cmos->rtc = NULL;
 871
 872         ports = cmos->iomem;
 873         if (RTC_IOMAPPED)
 874                 release_region(ports->start, resource_size(ports));
 875         else
 876                 release_mem_region(ports->start, resource_size(ports));
 877         cmos->iomem = NULL;
 878
 879         cmos->dev = NULL;
 880 }
 881
 882 static int cmos_aie_poweroff(struct device *dev)
 883 {
 884         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 885         struct rtc_time now;
 886         time64_t t_now;
 887         int retval = 0;
 888         unsigned char rtc_control;
 889
 890         if (!cmos->alarm_expires)
 891                 return -EINVAL;
 892
 893         spin_lock_irq(&rtc_lock);
 894         rtc_control = CMOS_READ(RTC_CONTROL);
 895         spin_unlock_irq(&rtc_lock);
 896
 897         /* We only care about the situation where AIE is disabled. */
 898         if (rtc_control & RTC_AIE)
 899                 return -EBUSY;
 900
 901         cmos_read_time(dev, &now);
 902         t_now = rtc_tm_to_time64(&now);
 903
 904         /*
 905          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
 906          * automatically right after shutdown on some buggy boxes.
 907          * This automatic rebooting issue won't happen when the alarm
 908          * time is larger than now+1 seconds.
 909          *
 910          * If the alarm time is equal to now+1 seconds, the issue can be
 911          * prevented by cancelling the alarm.
 912          */
 913         if (cmos->alarm_expires == t_now + 1) {
 914                 struct rtc_wkalrm alarm;
 915
 916                 /* Cancel the AIE timer by configuring the past time. */
 917                 rtc_time64_to_tm(t_now - 1, &alarm.time);
 918                 alarm.enabled = 0;
 919                 retval = cmos_set_alarm(dev, &alarm);
 920         } else if (cmos->alarm_expires > t_now + 1) {
 921                 retval = -EBUSY;
 922         }
 923
 924         return retval;
 925 }
 926
 927 static int cmos_suspend(struct device *dev)
 928 {
 929         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 930         unsigned char   tmp;
 931
 932         /* only the alarm might be a wakeup event source */
 933         spin_lock_irq(&rtc_lock);
 934         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 935         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 936                 unsigned char   mask;
 937
 938                 if (device_may_wakeup(dev))
 939                         mask = RTC_IRQMASK & ~RTC_AIE;
 940                 else
 941                         mask = RTC_IRQMASK;
 942                 tmp &= ~mask;
 943                 CMOS_WRITE(tmp, RTC_CONTROL);
 944                 hpet_mask_rtc_irq_bit(mask);
 945
 946                 cmos_checkintr(cmos, tmp);
 947         }
 948         spin_unlock_irq(&rtc_lock);
 949
 950         if (tmp & RTC_AIE) {
 951                 cmos->enabled_wake = 1;
 952                 if (cmos->wake_on)
 953                         cmos->wake_on(dev);
 954                 else
 955                         enable_irq_wake(cmos->irq);
 956         }
 957
 958         cmos_read_alarm(dev, &cmos->saved_wkalrm);
 959
 960         dev_dbg(dev, "suspend%s, ctrl %02x\n",
 961                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
 962                         tmp);
 963
 964         return 0;
 965 }
 966
 967 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
 968  * after a detour through G3 "mechanical off", although the ACPI spec
 969  * says wakeup should only work from G1/S4 "hibernate".  To most users,
 970  * distinctions between S4 and S5 are pointless.  So when the hardware
 971  * allows, don't draw that distinction.
 972  */
 973 static inline int cmos_poweroff(struct device *dev)
 974 {
 975         if (!IS_ENABLED(CONFIG_PM))
 976                 return -ENOSYS;
 977
 978         return cmos_suspend(dev);
 979 }
 980
 981 static void cmos_check_wkalrm(struct device *dev)
 982 {
 983         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 984         struct rtc_wkalrm current_alarm;
 985         time64_t t_current_expires;
 986         time64_t t_saved_expires;
 987
 988         cmos_read_alarm(dev, &current_alarm);
 989         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
 990         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
 991         if (t_current_expires != t_saved_expires ||
 992             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
 993                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
 994         }
 995 }
 996
 997 static void cmos_check_acpi_rtc_status(struct device *dev,
 998                                        unsigned char *rtc_control);
 999
1000 static int __maybe_unused cmos_resume(struct device *dev)
1001 {
1002         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1003         unsigned char tmp;
1004
1005         if (cmos->enabled_wake) {
1006                 if (cmos->wake_off)
1007                         cmos->wake_off(dev);
1008                 else
1009                         disable_irq_wake(cmos->irq);
1010                 cmos->enabled_wake = 0;
1011         }
1012
1013         /* The BIOS might have changed the alarm, restore it */
1014         cmos_check_wkalrm(dev);
1015
1016         spin_lock_irq(&rtc_lock);
1017         tmp = cmos->suspend_ctrl;
1018         cmos->suspend_ctrl = 0;
1019         /* re-enable any irqs previously active */
1020         if (tmp & RTC_IRQMASK) {
1021                 unsigned char   mask;
1022
1023                 if (device_may_wakeup(dev))
1024                         hpet_rtc_timer_init();
1025
1026                 do {
1027                         CMOS_WRITE(tmp, RTC_CONTROL);
1028                         hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1029
1030                         mask = CMOS_READ(RTC_INTR_FLAGS);
1031                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1032                         if (!is_hpet_enabled() || !is_intr(mask))
1033                                 break;
1034
1035                         /* force one-shot behavior if HPET blocked
1036                          * the wake alarm's irq
1037                          */
1038                         rtc_update_irq(cmos->rtc, 1, mask);
1039                         tmp &= ~RTC_AIE;
1040                         hpet_mask_rtc_irq_bit(RTC_AIE);
1041                 } while (mask & RTC_AIE);
1042
1043                 if (tmp & RTC_AIE)
1044                         cmos_check_acpi_rtc_status(dev, &tmp);
1045         }
1046         spin_unlock_irq(&rtc_lock);
1047
1048         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1049
1050         return 0;
1051 }
1052
1053 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1054
1055 /*----------------------------------------------------------------*/
1056
1057 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1058  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1059  * probably list them in similar PNPBIOS tables; so PNP is more common.
1060  *
1061  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1062  * predate even PNPBIOS should set up platform_bus devices.
1063  */
1064
1065 #ifdef  CONFIG_ACPI
1066
1067 #include <linux/acpi.h>
1068
1069 static u32 rtc_handler(void *context)
1070 {
1071         struct device *dev = context;
1072         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1073         unsigned char rtc_control = 0;
1074         unsigned char rtc_intr;
1075         unsigned long flags;
1076
1077         spin_lock_irqsave(&rtc_lock, flags);
1078         if (cmos_rtc.suspend_ctrl)
1079                 rtc_control = CMOS_READ(RTC_CONTROL);
1080         if (rtc_control & RTC_AIE) {
1081                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1082                 CMOS_WRITE(rtc_control, RTC_CONTROL);
1083                 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1084                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
1085         }
1086         spin_unlock_irqrestore(&rtc_lock, flags);
1087
1088         pm_wakeup_event(dev, 0);
1089         acpi_clear_event(ACPI_EVENT_RTC);
1090         acpi_disable_event(ACPI_EVENT_RTC, 0);
1091         return ACPI_INTERRUPT_HANDLED;
1092 }
1093
1094 static inline void rtc_wake_setup(struct device *dev)
1095 {
1096         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1097         /*
1098          * After the RTC handler is installed, the Fixed_RTC event should
1099          * be disabled. Only when the RTC alarm is set will it be enabled.
1100          */
1101         acpi_clear_event(ACPI_EVENT_RTC);
1102         acpi_disable_event(ACPI_EVENT_RTC, 0);
1103 }
1104
1105 static void rtc_wake_on(struct device *dev)
1106 {
1107         acpi_clear_event(ACPI_EVENT_RTC);
1108         acpi_enable_event(ACPI_EVENT_RTC, 0);
1109 }
1110
1111 static void rtc_wake_off(struct device *dev)
1112 {
1113         acpi_disable_event(ACPI_EVENT_RTC, 0);
1114 }
1115
1116 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1117  * its device node and pass extra config data.  This helps its driver use
1118  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1119  * that this board's RTC is wakeup-capable (per ACPI spec).
1120  */
1121 static struct cmos_rtc_board_info acpi_rtc_info;
1122
1123 static void cmos_wake_setup(struct device *dev)
1124 {
1125         if (acpi_disabled)
1126                 return;
1127
1128         rtc_wake_setup(dev);
1129         acpi_rtc_info.wake_on = rtc_wake_on;
1130         acpi_rtc_info.wake_off = rtc_wake_off;
1131
1132         /* workaround bug in some ACPI tables */
1133         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1134                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1135                         acpi_gbl_FADT.month_alarm);
1136                 acpi_gbl_FADT.month_alarm = 0;
1137         }
1138
1139         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1140         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1141         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1142
1143         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1144         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1145                 dev_info(dev, "RTC can wake from S4\n");
1146
1147         dev->platform_data = &acpi_rtc_info;
1148
1149         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1150         device_init_wakeup(dev, 1);
1151 }
1152
1153 static void cmos_check_acpi_rtc_status(struct device *dev,
1154                                        unsigned char *rtc_control)
1155 {
1156         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1157         acpi_event_status rtc_status;
1158         acpi_status status;
1159
1160         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1161                 return;
1162
1163         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1164         if (ACPI_FAILURE(status)) {
1165                 dev_err(dev, "Could not get RTC status\n");
1166         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1167                 unsigned char mask;
1168                 *rtc_control &= ~RTC_AIE;
1169                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1170                 mask = CMOS_READ(RTC_INTR_FLAGS);
1171                 rtc_update_irq(cmos->rtc, 1, mask);
1172         }
1173 }
1174
1175 #else
1176
1177 static void cmos_wake_setup(struct device *dev)
1178 {
1179 }
1180
1181 static void cmos_check_acpi_rtc_status(struct device *dev,
1182                                        unsigned char *rtc_control)
1183 {
1184 }
1185
1186 #endif
1187
1188 #ifdef  CONFIG_PNP
1189
1190 #include <linux/pnp.h>
1191
1192 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1193 {
1194         cmos_wake_setup(&pnp->dev);
1195
1196         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0))
1197                 /* Some machines contain a PNP entry for the RTC, but
1198                  * don't define the IRQ. It should always be safe to
1199                  * hardcode it in these cases
1200                  */
1201                 return cmos_do_probe(&pnp->dev,
1202                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), 8);
1203         else
1204                 return cmos_do_probe(&pnp->dev,
1205                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1206                                 pnp_irq(pnp, 0));
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         struct rtc_time time;
1266         int ret;
1267         const __be32 *val;
1268
1269         if (!node)
1270                 return;
1271
1272         val = of_get_property(node, "ctrl-reg", NULL);
1273         if (val)
1274                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1275
1276         val = of_get_property(node, "freq-reg", NULL);
1277         if (val)
1278                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1279
1280         cmos_read_time(&pdev->dev, &time);
1281         ret = rtc_valid_tm(&time);
1282         if (ret) {
1283                 struct rtc_time def_time = {
1284                         .tm_year = 1,
1285                         .tm_mday = 1,
1286                 };
1287                 cmos_set_time(&pdev->dev, &def_time);
1288         }
1289 }
1290 #else
1291 static inline void cmos_of_init(struct platform_device *pdev) {}
1292 #endif
1293 /*----------------------------------------------------------------*/
1294
1295 /* Platform setup should have set up an RTC device, when PNP is
1296  * unavailable ... this could happen even on (older) PCs.
1297  */
1298
1299 static int __init cmos_platform_probe(struct platform_device *pdev)
1300 {
1301         struct resource *resource;
1302         int irq;
1303
1304         cmos_of_init(pdev);
1305         cmos_wake_setup(&pdev->dev);
1306
1307         if (RTC_IOMAPPED)
1308                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1309         else
1310                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1311         irq = platform_get_irq(pdev, 0);
1312         if (irq < 0)
1313                 irq = -1;
1314
1315         return cmos_do_probe(&pdev->dev, resource, irq);
1316 }
1317
1318 static int cmos_platform_remove(struct platform_device *pdev)
1319 {
1320         cmos_do_remove(&pdev->dev);
1321         return 0;
1322 }
1323
1324 static void cmos_platform_shutdown(struct platform_device *pdev)
1325 {
1326         struct device *dev = &pdev->dev;
1327         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1328
1329         if (system_state == SYSTEM_POWER_OFF) {
1330                 int retval = cmos_poweroff(dev);
1331
1332                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1333                         return;
1334         }
1335
1336         cmos_do_shutdown(cmos->irq);
1337 }
1338
1339 /* work with hotplug and coldplug */
1340 MODULE_ALIAS("platform:rtc_cmos");
1341
1342 static struct platform_driver cmos_platform_driver = {
1343         .remove         = cmos_platform_remove,
1344         .shutdown       = cmos_platform_shutdown,
1345         .driver = {
1346                 .name           = driver_name,
1347                 .pm             = &cmos_pm_ops,
1348                 .of_match_table = of_match_ptr(of_cmos_match),
1349         }
1350 };
1351
1352 #ifdef CONFIG_PNP
1353 static bool pnp_driver_registered;
1354 #endif
1355 static bool platform_driver_registered;
1356
1357 static int __init cmos_init(void)
1358 {
1359         int retval = 0;
1360
1361 #ifdef  CONFIG_PNP
1362         retval = pnp_register_driver(&cmos_pnp_driver);
1363         if (retval == 0)
1364                 pnp_driver_registered = true;
1365 #endif
1366
1367         if (!cmos_rtc.dev) {
1368                 retval = platform_driver_probe(&cmos_platform_driver,
1369                                                cmos_platform_probe);
1370                 if (retval == 0)
1371                         platform_driver_registered = true;
1372         }
1373
1374         if (retval == 0)
1375                 return 0;
1376
1377 #ifdef  CONFIG_PNP
1378         if (pnp_driver_registered)
1379                 pnp_unregister_driver(&cmos_pnp_driver);
1380 #endif
1381         return retval;
1382 }
1383 module_init(cmos_init);
1384
1385 static void __exit cmos_exit(void)
1386 {
1387 #ifdef  CONFIG_PNP
1388         if (pnp_driver_registered)
1389                 pnp_unregister_driver(&cmos_pnp_driver);
1390 #endif
1391         if (platform_driver_registered)
1392                 platform_driver_unregister(&cmos_platform_driver);
1393 }
1394 module_exit(cmos_exit);
1395
1396
1397 MODULE_AUTHOR("David Brownell");
1398 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1399 MODULE_LICENSE("GPL");