drivers/rtc/rtc-cmos.c

   1 /*
   2  * RTC class driver for "CMOS RTC":  PCs, ACPI, etc
   3  *
   4  * Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c)
   5  * Copyright (C) 2006 David Brownell (convert to new framework)
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the License, or (at your option) any later version.
  11  */
  12
  13 /*
  14  * The original "cmos clock" chip was an MC146818 chip, now obsolete.
  15  * That defined the register interface now provided by all PCs, some
  16  * non-PC systems, and incorporated into ACPI.  Modern PC chipsets
  17  * integrate an MC146818 clone in their southbridge, and boards use
  18  * that instead of discrete clones like the DS12887 or M48T86.  There
  19  * are also clones that connect using the LPC bus.
  20  *
  21  * That register API is also used directly by various other drivers
  22  * (notably for integrated NVRAM), infrastructure (x86 has code to
  23  * bypass the RTC framework, directly reading the RTC during boot
  24  * and updating minutes/seconds for systems using NTP synch) and
  25  * utilities (like userspace 'hwclock', if no /dev node exists).
  26  *
  27  * So **ALL** calls to CMOS_READ and CMOS_WRITE must be done with
  28  * interrupts disabled, holding the global rtc_lock, to exclude those
  29  * other drivers and utilities on correctly configured systems.
  30  */
  31
  32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  33
  34 #include <linux/kernel.h>
  35 #include <linux/module.h>
  36 #include <linux/init.h>
  37 #include <linux/interrupt.h>
  38 #include <linux/spinlock.h>
  39 #include <linux/platform_device.h>
  40 #include <linux/log2.h>
  41 #include <linux/pm.h>
  42 #include <linux/of.h>
  43 #include <linux/of_platform.h>
  44 #ifdef CONFIG_X86
  45 #include <asm/i8259.h>
  46 #endif
  47
  48 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
  49 #include <linux/mc146818rtc.h>
  50
  51 struct cmos_rtc {
  52         struct rtc_device       *rtc;
  53         struct device           *dev;
  54         int                     irq;
  55         struct resource         *iomem;
  56         time64_t                alarm_expires;
  57
  58         void                    (*wake_on)(struct device *);
  59         void                    (*wake_off)(struct device *);
  60
  61         u8                      enabled_wake;
  62         u8                      suspend_ctrl;
  63
  64         /* newer hardware extends the original register set */
  65         u8                      day_alrm;
  66         u8                      mon_alrm;
  67         u8                      century;
  68
  69         struct rtc_wkalrm       saved_wkalrm;
  70 };
  71
  72 /* both platform and pnp busses use negative numbers for invalid irqs */
  73 #define is_valid_irq(n)         ((n) > 0)
  74
  75 static const char driver_name[] = "rtc_cmos";
  76
  77 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
  78  * always mask it against the irq enable bits in RTC_CONTROL.  Bit values
  79  * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
  80  */
  81 #define RTC_IRQMASK     (RTC_PF | RTC_AF | RTC_UF)
  82
  83 static inline int is_intr(u8 rtc_intr)
  84 {
  85         if (!(rtc_intr & RTC_IRQF))
  86                 return 0;
  87         return rtc_intr & RTC_IRQMASK;
  88 }
  89
  90 /*----------------------------------------------------------------*/
  91
  92 /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
  93  * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
  94  * used in a broken "legacy replacement" mode.  The breakage includes
  95  * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
  96  * other (better) use.
  97  *
  98  * When that broken mode is in use, platform glue provides a partial
  99  * emulation of hardware RTC IRQ facilities using HPET #1.  We don't
 100  * want to use HPET for anything except those IRQs though...
 101  */
 102 #ifdef CONFIG_HPET_EMULATE_RTC
 103 #include <asm/hpet.h>
 104 #else
 105
 106 static inline int is_hpet_enabled(void)
 107 {
 108         return 0;
 109 }
 110
 111 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
 112 {
 113         return 0;
 114 }
 115
 116 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
 117 {
 118         return 0;
 119 }
 120
 121 static inline int
 122 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
 123 {
 124         return 0;
 125 }
 126
 127 static inline int hpet_set_periodic_freq(unsigned long freq)
 128 {
 129         return 0;
 130 }
 131
 132 static inline int hpet_rtc_dropped_irq(void)
 133 {
 134         return 0;
 135 }
 136
 137 static inline int hpet_rtc_timer_init(void)
 138 {
 139         return 0;
 140 }
 141
 142 extern irq_handler_t hpet_rtc_interrupt;
 143
 144 static inline int hpet_register_irq_handler(irq_handler_t handler)
 145 {
 146         return 0;
 147 }
 148
 149 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
 150 {
 151         return 0;
 152 }
 153
 154 #endif
 155
 156 /*----------------------------------------------------------------*/
 157
 158 #ifdef RTC_PORT
 159
 160 /* Most newer x86 systems have two register banks, the first used
 161  * for RTC and NVRAM and the second only for NVRAM.  Caller must
 162  * own rtc_lock ... and we won't worry about access during NMI.
 163  */
 164 #define can_bank2       true
 165
 166 static inline unsigned char cmos_read_bank2(unsigned char addr)
 167 {
 168         outb(addr, RTC_PORT(2));
 169         return inb(RTC_PORT(3));
 170 }
 171
 172 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 173 {
 174         outb(addr, RTC_PORT(2));
 175         outb(val, RTC_PORT(3));
 176 }
 177
 178 #else
 179
 180 #define can_bank2       false
 181
 182 static inline unsigned char cmos_read_bank2(unsigned char addr)
 183 {
 184         return 0;
 185 }
 186
 187 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 188 {
 189 }
 190
 191 #endif
 192
 193 /*----------------------------------------------------------------*/
 194
 195 static int cmos_read_time(struct device *dev, struct rtc_time *t)
 196 {
 197         /*
 198          * If pm_trace abused the RTC for storage, set the timespec to 0,
 199          * which tells the caller that this RTC value is unusable.
 200          */
 201         if (!pm_trace_rtc_valid())
 202                 return -EIO;
 203
 204         /* REVISIT:  if the clock has a "century" register, use
 205          * that instead of the heuristic in mc146818_get_time().
 206          * That'll make Y3K compatility (year > 2070) easy!
 207          */
 208         mc146818_get_time(t);
 209         return 0;
 210 }
 211
 212 static int cmos_set_time(struct device *dev, struct rtc_time *t)
 213 {
 214         /* REVISIT:  set the "century" register if available
 215          *
 216          * NOTE: this ignores the issue whereby updating the seconds
 217          * takes effect exactly 500ms after we write the register.
 218          * (Also queueing and other delays before we get this far.)
 219          */
 220         return mc146818_set_time(t);
 221 }
 222
 223 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 224 {
 225         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 226         unsigned char   rtc_control;
 227
 228         if (!is_valid_irq(cmos->irq))
 229                 return -EIO;
 230
 231         /* Basic alarms only support hour, minute, and seconds fields.
 232          * Some also support day and month, for alarms up to a year in
 233          * the future.
 234          */
 235
 236         spin_lock_irq(&rtc_lock);
 237         t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 238         t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 239         t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 240
 241         if (cmos->day_alrm) {
 242                 /* ignore upper bits on readback per ACPI spec */
 243                 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
 244                 if (!t->time.tm_mday)
 245                         t->time.tm_mday = -1;
 246
 247                 if (cmos->mon_alrm) {
 248                         t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
 249                         if (!t->time.tm_mon)
 250                                 t->time.tm_mon = -1;
 251                 }
 252         }
 253
 254         rtc_control = CMOS_READ(RTC_CONTROL);
 255         spin_unlock_irq(&rtc_lock);
 256
 257         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 258                 if (((unsigned)t->time.tm_sec) < 0x60)
 259                         t->time.tm_sec = bcd2bin(t->time.tm_sec);
 260                 else
 261                         t->time.tm_sec = -1;
 262                 if (((unsigned)t->time.tm_min) < 0x60)
 263                         t->time.tm_min = bcd2bin(t->time.tm_min);
 264                 else
 265                         t->time.tm_min = -1;
 266                 if (((unsigned)t->time.tm_hour) < 0x24)
 267                         t->time.tm_hour = bcd2bin(t->time.tm_hour);
 268                 else
 269                         t->time.tm_hour = -1;
 270
 271                 if (cmos->day_alrm) {
 272                         if (((unsigned)t->time.tm_mday) <= 0x31)
 273                                 t->time.tm_mday = bcd2bin(t->time.tm_mday);
 274                         else
 275                                 t->time.tm_mday = -1;
 276
 277                         if (cmos->mon_alrm) {
 278                                 if (((unsigned)t->time.tm_mon) <= 0x12)
 279                                         t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
 280                                 else
 281                                         t->time.tm_mon = -1;
 282                         }
 283                 }
 284         }
 285
 286         t->enabled = !!(rtc_control & RTC_AIE);
 287         t->pending = 0;
 288
 289         return 0;
 290 }
 291
 292 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
 293 {
 294         unsigned char   rtc_intr;
 295
 296         /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 297          * allegedly some older rtcs need that to handle irqs properly
 298          */
 299         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 300
 301         if (is_hpet_enabled())
 302                 return;
 303
 304         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 305         if (is_intr(rtc_intr))
 306                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 307 }
 308
 309 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
 310 {
 311         unsigned char   rtc_control;
 312
 313         /* flush any pending IRQ status, notably for update irqs,
 314          * before we enable new IRQs
 315          */
 316         rtc_control = CMOS_READ(RTC_CONTROL);
 317         cmos_checkintr(cmos, rtc_control);
 318
 319         rtc_control |= mask;
 320         CMOS_WRITE(rtc_control, RTC_CONTROL);
 321         hpet_set_rtc_irq_bit(mask);
 322
 323         cmos_checkintr(cmos, rtc_control);
 324 }
 325
 326 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 327 {
 328         unsigned char   rtc_control;
 329
 330         rtc_control = CMOS_READ(RTC_CONTROL);
 331         rtc_control &= ~mask;
 332         CMOS_WRITE(rtc_control, RTC_CONTROL);
 333         hpet_mask_rtc_irq_bit(mask);
 334
 335         cmos_checkintr(cmos, rtc_control);
 336 }
 337
 338 static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
 339 {
 340         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 341         struct rtc_time now;
 342
 343         cmos_read_time(dev, &now);
 344
 345         if (!cmos->day_alrm) {
 346                 time64_t t_max_date;
 347                 time64_t t_alrm;
 348
 349                 t_max_date = rtc_tm_to_time64(&now);
 350                 t_max_date += 24 * 60 * 60 - 1;
 351                 t_alrm = rtc_tm_to_time64(&t->time);
 352                 if (t_alrm > t_max_date) {
 353                         dev_err(dev,
 354                                 "Alarms can be up to one day in the future\n");
 355                         return -EINVAL;
 356                 }
 357         } else if (!cmos->mon_alrm) {
 358                 struct rtc_time max_date = now;
 359                 time64_t t_max_date;
 360                 time64_t t_alrm;
 361                 int max_mday;
 362
 363                 if (max_date.tm_mon == 11) {
 364                         max_date.tm_mon = 0;
 365                         max_date.tm_year += 1;
 366                 } else {
 367                         max_date.tm_mon += 1;
 368                 }
 369                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 370                 if (max_date.tm_mday > max_mday)
 371                         max_date.tm_mday = max_mday;
 372
 373                 t_max_date = rtc_tm_to_time64(&max_date);
 374                 t_max_date -= 1;
 375                 t_alrm = rtc_tm_to_time64(&t->time);
 376                 if (t_alrm > t_max_date) {
 377                         dev_err(dev,
 378                                 "Alarms can be up to one month in the future\n");
 379                         return -EINVAL;
 380                 }
 381         } else {
 382                 struct rtc_time max_date = now;
 383                 time64_t t_max_date;
 384                 time64_t t_alrm;
 385                 int max_mday;
 386
 387                 max_date.tm_year += 1;
 388                 max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
 389                 if (max_date.tm_mday > max_mday)
 390                         max_date.tm_mday = max_mday;
 391
 392                 t_max_date = rtc_tm_to_time64(&max_date);
 393                 t_max_date -= 1;
 394                 t_alrm = rtc_tm_to_time64(&t->time);
 395                 if (t_alrm > t_max_date) {
 396                         dev_err(dev,
 397                                 "Alarms can be up to one year in the future\n");
 398                         return -EINVAL;
 399                 }
 400         }
 401
 402         return 0;
 403 }
 404
 405 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 406 {
 407         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 408         unsigned char mon, mday, hrs, min, sec, rtc_control;
 409         int ret;
 410
 411         if (!is_valid_irq(cmos->irq))
 412                 return -EIO;
 413
 414         ret = cmos_validate_alarm(dev, t);
 415         if (ret < 0)
 416                 return ret;
 417
 418         mon = t->time.tm_mon + 1;
 419         mday = t->time.tm_mday;
 420         hrs = t->time.tm_hour;
 421         min = t->time.tm_min;
 422         sec = t->time.tm_sec;
 423
 424         rtc_control = CMOS_READ(RTC_CONTROL);
 425         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 426                 /* Writing 0xff means "don't care" or "match all".  */
 427                 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
 428                 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 429                 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
 430                 min = (min < 60) ? bin2bcd(min) : 0xff;
 431                 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
 432         }
 433
 434         spin_lock_irq(&rtc_lock);
 435
 436         /* next rtc irq must not be from previous alarm setting */
 437         cmos_irq_disable(cmos, RTC_AIE);
 438
 439         /* update alarm */
 440         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 441         CMOS_WRITE(min, RTC_MINUTES_ALARM);
 442         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 443
 444         /* the system may support an "enhanced" alarm */
 445         if (cmos->day_alrm) {
 446                 CMOS_WRITE(mday, cmos->day_alrm);
 447                 if (cmos->mon_alrm)
 448                         CMOS_WRITE(mon, cmos->mon_alrm);
 449         }
 450
 451         /* FIXME the HPET alarm glue currently ignores day_alrm
 452          * and mon_alrm ...
 453          */
 454         hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
 455
 456         if (t->enabled)
 457                 cmos_irq_enable(cmos, RTC_AIE);
 458
 459         spin_unlock_irq(&rtc_lock);
 460
 461         cmos->alarm_expires = rtc_tm_to_time64(&t->time);
 462
 463         return 0;
 464 }
 465
 466 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 467 {
 468         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 469         unsigned long   flags;
 470
 471         if (!is_valid_irq(cmos->irq))
 472                 return -EINVAL;
 473
 474         spin_lock_irqsave(&rtc_lock, flags);
 475
 476         if (enabled)
 477                 cmos_irq_enable(cmos, RTC_AIE);
 478         else
 479                 cmos_irq_disable(cmos, RTC_AIE);
 480
 481         spin_unlock_irqrestore(&rtc_lock, flags);
 482         return 0;
 483 }
 484
 485 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
 486
 487 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 488 {
 489         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 490         unsigned char   rtc_control, valid;
 491
 492         spin_lock_irq(&rtc_lock);
 493         rtc_control = CMOS_READ(RTC_CONTROL);
 494         valid = CMOS_READ(RTC_VALID);
 495         spin_unlock_irq(&rtc_lock);
 496
 497         /* NOTE:  at least ICH6 reports battery status using a different
 498          * (non-RTC) bit; and SQWE is ignored on many current systems.
 499          */
 500         seq_printf(seq,
 501                    "periodic_IRQ\t: %s\n"
 502                    "update_IRQ\t: %s\n"
 503                    "HPET_emulated\t: %s\n"
 504                    // "square_wave\t: %s\n"
 505                    "BCD\t\t: %s\n"
 506                    "DST_enable\t: %s\n"
 507                    "periodic_freq\t: %d\n"
 508                    "batt_status\t: %s\n",
 509                    (rtc_control & RTC_PIE) ? "yes" : "no",
 510                    (rtc_control & RTC_UIE) ? "yes" : "no",
 511                    is_hpet_enabled() ? "yes" : "no",
 512                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
 513                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 514                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
 515                    cmos->rtc->irq_freq,
 516                    (valid & RTC_VRT) ? "okay" : "dead");
 517
 518         return 0;
 519 }
 520
 521 #else
 522 #define cmos_procfs     NULL
 523 #endif
 524
 525 static const struct rtc_class_ops cmos_rtc_ops = {
 526         .read_time              = cmos_read_time,
 527         .set_time               = cmos_set_time,
 528         .read_alarm             = cmos_read_alarm,
 529         .set_alarm              = cmos_set_alarm,
 530         .proc                   = cmos_procfs,
 531         .alarm_irq_enable       = cmos_alarm_irq_enable,
 532 };
 533
 534 /*----------------------------------------------------------------*/
 535
 536 /*
 537  * All these chips have at least 64 bytes of address space, shared by
 538  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 539  * by boot firmware.  Modern chips have 128 or 256 bytes.
 540  */
 541
 542 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 543
 544 static int cmos_nvram_read(void *priv, unsigned int off, void *val,
 545                            size_t count)
 546 {
 547         unsigned char *buf = val;
 548         int     retval;
 549
 550         off += NVRAM_OFFSET;
 551         spin_lock_irq(&rtc_lock);
 552         for (retval = 0; count; count--, off++, retval++) {
 553                 if (off < 128)
 554                         *buf++ = CMOS_READ(off);
 555                 else if (can_bank2)
 556                         *buf++ = cmos_read_bank2(off);
 557                 else
 558                         break;
 559         }
 560         spin_unlock_irq(&rtc_lock);
 561
 562         return retval;
 563 }
 564
 565 static int cmos_nvram_write(void *priv, unsigned int off, void *val,
 566                             size_t count)
 567 {
 568         struct cmos_rtc *cmos = priv;
 569         unsigned char   *buf = val;
 570         int             retval;
 571
 572         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 573          * checksum on part of the NVRAM data.  That's currently ignored
 574          * here.  If userspace is smart enough to know what fields of
 575          * NVRAM to update, updating checksums is also part of its job.
 576          */
 577         off += NVRAM_OFFSET;
 578         spin_lock_irq(&rtc_lock);
 579         for (retval = 0; count; count--, off++, retval++) {
 580                 /* don't trash RTC registers */
 581                 if (off == cmos->day_alrm
 582                                 || off == cmos->mon_alrm
 583                                 || off == cmos->century)
 584                         buf++;
 585                 else if (off < 128)
 586                         CMOS_WRITE(*buf++, off);
 587                 else if (can_bank2)
 588                         cmos_write_bank2(*buf++, off);
 589                 else
 590                         break;
 591         }
 592         spin_unlock_irq(&rtc_lock);
 593
 594         return retval;
 595 }
 596
 597 /*----------------------------------------------------------------*/
 598
 599 static struct cmos_rtc  cmos_rtc;
 600
 601 static irqreturn_t cmos_interrupt(int irq, void *p)
 602 {
 603         u8              irqstat;
 604         u8              rtc_control;
 605
 606         spin_lock(&rtc_lock);
 607
 608         /* When the HPET interrupt handler calls us, the interrupt
 609          * status is passed as arg1 instead of the irq number.  But
 610          * always clear irq status, even when HPET is in the way.
 611          *
 612          * Note that HPET and RTC are almost certainly out of phase,
 613          * giving different IRQ status ...
 614          */
 615         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 616         rtc_control = CMOS_READ(RTC_CONTROL);
 617         if (is_hpet_enabled())
 618                 irqstat = (unsigned long)irq & 0xF0;
 619
 620         /* If we were suspended, RTC_CONTROL may not be accurate since the
 621          * bios may have cleared it.
 622          */
 623         if (!cmos_rtc.suspend_ctrl)
 624                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 625         else
 626                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 627
 628         /* All Linux RTC alarms should be treated as if they were oneshot.
 629          * Similar code may be needed in system wakeup paths, in case the
 630          * alarm woke the system.
 631          */
 632         if (irqstat & RTC_AIE) {
 633                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 634                 rtc_control &= ~RTC_AIE;
 635                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 636                 hpet_mask_rtc_irq_bit(RTC_AIE);
 637                 CMOS_READ(RTC_INTR_FLAGS);
 638         }
 639         spin_unlock(&rtc_lock);
 640
 641         if (is_intr(irqstat)) {
 642                 rtc_update_irq(p, 1, irqstat);
 643                 return IRQ_HANDLED;
 644         } else
 645                 return IRQ_NONE;
 646 }
 647
 648 #ifdef  CONFIG_PNP
 649 #define INITSECTION
 650
 651 #else
 652 #define INITSECTION     __init
 653 #endif
 654
 655 static int INITSECTION
 656 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 657 {
 658         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 659         int                             retval = 0;
 660         unsigned char                   rtc_control;
 661         unsigned                        address_space;
 662         u32                             flags = 0;
 663         struct nvmem_config nvmem_cfg = {
 664                 .name = "cmos_nvram",
 665                 .word_size = 1,
 666                 .stride = 1,
 667                 .reg_read = cmos_nvram_read,
 668                 .reg_write = cmos_nvram_write,
 669                 .priv = &cmos_rtc,
 670         };
 671
 672         /* there can be only one ... */
 673         if (cmos_rtc.dev)
 674                 return -EBUSY;
 675
 676         if (!ports)
 677                 return -ENODEV;
 678
 679         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 680          *
 681          * REVISIT non-x86 systems may instead use memory space resources
 682          * (needing ioremap etc), not i/o space resources like this ...
 683          */
 684         if (RTC_IOMAPPED)
 685                 ports = request_region(ports->start, resource_size(ports),
 686                                        driver_name);
 687         else
 688                 ports = request_mem_region(ports->start, resource_size(ports),
 689                                            driver_name);
 690         if (!ports) {
 691                 dev_dbg(dev, "i/o registers already in use\n");
 692                 return -EBUSY;
 693         }
 694
 695         cmos_rtc.irq = rtc_irq;
 696         cmos_rtc.iomem = ports;
 697
 698         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 699          * driver did, but don't reject unknown configs.   Old hardware
 700          * won't address 128 bytes.  Newer chips have multiple banks,
 701          * though they may not be listed in one I/O resource.
 702          */
 703 #if     defined(CONFIG_ATARI)
 704         address_space = 64;
 705 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 706                         || defined(__sparc__) || defined(__mips__) \
 707                         || defined(__powerpc__)
 708         address_space = 128;
 709 #else
 710 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 711         address_space = 128;
 712 #endif
 713         if (can_bank2 && ports->end > (ports->start + 1))
 714                 address_space = 256;
 715
 716         /* For ACPI systems extension info comes from the FADT.  On others,
 717          * board specific setup provides it as appropriate.  Systems where
 718          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 719          * some almost-clones) can provide hooks to make that behave.
 720          *
 721          * Note that ACPI doesn't preclude putting these registers into
 722          * "extended" areas of the chip, including some that we won't yet
 723          * expect CMOS_READ and friends to handle.
 724          */
 725         if (info) {
 726                 if (info->flags)
 727                         flags = info->flags;
 728                 if (info->address_space)
 729                         address_space = info->address_space;
 730
 731                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 732                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 733                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 734                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 735                 if (info->rtc_century && info->rtc_century < 128)
 736                         cmos_rtc.century = info->rtc_century;
 737
 738                 if (info->wake_on && info->wake_off) {
 739                         cmos_rtc.wake_on = info->wake_on;
 740                         cmos_rtc.wake_off = info->wake_off;
 741                 }
 742         }
 743
 744         cmos_rtc.dev = dev;
 745         dev_set_drvdata(dev, &cmos_rtc);
 746
 747         cmos_rtc.rtc = devm_rtc_allocate_device(dev);
 748         if (IS_ERR(cmos_rtc.rtc)) {
 749                 retval = PTR_ERR(cmos_rtc.rtc);
 750                 goto cleanup0;
 751         }
 752
 753         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 754
 755         spin_lock_irq(&rtc_lock);
 756
 757         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 758                 /* force periodic irq to CMOS reset default of 1024Hz;
 759                  *
 760                  * REVISIT it's been reported that at least one x86_64 ALI
 761                  * mobo doesn't use 32KHz here ... for portability we might
 762                  * need to do something about other clock frequencies.
 763                  */
 764                 cmos_rtc.rtc->irq_freq = 1024;
 765                 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
 766                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 767         }
 768
 769         /* disable irqs */
 770         if (is_valid_irq(rtc_irq))
 771                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 772
 773         rtc_control = CMOS_READ(RTC_CONTROL);
 774
 775         spin_unlock_irq(&rtc_lock);
 776
 777         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
 778                 dev_warn(dev, "only 24-hr supported\n");
 779                 retval = -ENXIO;
 780                 goto cleanup1;
 781         }
 782
 783         hpet_rtc_timer_init();
 784
 785         if (is_valid_irq(rtc_irq)) {
 786                 irq_handler_t rtc_cmos_int_handler;
 787
 788                 if (is_hpet_enabled()) {
 789                         rtc_cmos_int_handler = hpet_rtc_interrupt;
 790                         retval = hpet_register_irq_handler(cmos_interrupt);
 791                         if (retval) {
 792                                 hpet_mask_rtc_irq_bit(RTC_IRQMASK);
 793                                 dev_warn(dev, "hpet_register_irq_handler "
 794                                                 " failed in rtc_init().");
 795                                 goto cleanup1;
 796                         }
 797                 } else
 798                         rtc_cmos_int_handler = cmos_interrupt;
 799
 800                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 801                                 IRQF_SHARED, dev_name(&cmos_rtc.rtc->dev),
 802                                 cmos_rtc.rtc);
 803                 if (retval < 0) {
 804                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 805                         goto cleanup1;
 806                 }
 807         }
 808
 809         cmos_rtc.rtc->ops = &cmos_rtc_ops;
 810         cmos_rtc.rtc->nvram_old_abi = true;
 811         retval = rtc_register_device(cmos_rtc.rtc);
 812         if (retval)
 813                 goto cleanup2;
 814
 815         /* export at least the first block of NVRAM */
 816         nvmem_cfg.size = address_space - NVRAM_OFFSET;
 817         if (rtc_nvmem_register(cmos_rtc.rtc, &nvmem_cfg))
 818                 dev_err(dev, "nvmem registration failed\n");
 819
 820         dev_info(dev, "%s%s, %d bytes nvram%s\n",
 821                  !is_valid_irq(rtc_irq) ? "no alarms" :
 822                  cmos_rtc.mon_alrm ? "alarms up to one year" :
 823                  cmos_rtc.day_alrm ? "alarms up to one month" :
 824                  "alarms up to one day",
 825                  cmos_rtc.century ? ", y3k" : "",
 826                  nvmem_cfg.size,
 827                  is_hpet_enabled() ? ", hpet irqs" : "");
 828
 829         return 0;
 830
 831 cleanup2:
 832         if (is_valid_irq(rtc_irq))
 833                 free_irq(rtc_irq, cmos_rtc.rtc);
 834 cleanup1:
 835         cmos_rtc.dev = NULL;
 836 cleanup0:
 837         if (RTC_IOMAPPED)
 838                 release_region(ports->start, resource_size(ports));
 839         else
 840                 release_mem_region(ports->start, resource_size(ports));
 841         return retval;
 842 }
 843
 844 static void cmos_do_shutdown(int rtc_irq)
 845 {
 846         spin_lock_irq(&rtc_lock);
 847         if (is_valid_irq(rtc_irq))
 848                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 849         spin_unlock_irq(&rtc_lock);
 850 }
 851
 852 static void cmos_do_remove(struct device *dev)
 853 {
 854         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 855         struct resource *ports;
 856
 857         cmos_do_shutdown(cmos->irq);
 858
 859         if (is_valid_irq(cmos->irq)) {
 860                 free_irq(cmos->irq, cmos->rtc);
 861                 hpet_unregister_irq_handler(cmos_interrupt);
 862         }
 863
 864         cmos->rtc = NULL;
 865
 866         ports = cmos->iomem;
 867         if (RTC_IOMAPPED)
 868                 release_region(ports->start, resource_size(ports));
 869         else
 870                 release_mem_region(ports->start, resource_size(ports));
 871         cmos->iomem = NULL;
 872
 873         cmos->dev = NULL;
 874 }
 875
 876 static int cmos_aie_poweroff(struct device *dev)
 877 {
 878         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 879         struct rtc_time now;
 880         time64_t t_now;
 881         int retval = 0;
 882         unsigned char rtc_control;
 883
 884         if (!cmos->alarm_expires)
 885                 return -EINVAL;
 886
 887         spin_lock_irq(&rtc_lock);
 888         rtc_control = CMOS_READ(RTC_CONTROL);
 889         spin_unlock_irq(&rtc_lock);
 890
 891         /* We only care about the situation where AIE is disabled. */
 892         if (rtc_control & RTC_AIE)
 893                 return -EBUSY;
 894
 895         cmos_read_time(dev, &now);
 896         t_now = rtc_tm_to_time64(&now);
 897
 898         /*
 899          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
 900          * automatically right after shutdown on some buggy boxes.
 901          * This automatic rebooting issue won't happen when the alarm
 902          * time is larger than now+1 seconds.
 903          *
 904          * If the alarm time is equal to now+1 seconds, the issue can be
 905          * prevented by cancelling the alarm.
 906          */
 907         if (cmos->alarm_expires == t_now + 1) {
 908                 struct rtc_wkalrm alarm;
 909
 910                 /* Cancel the AIE timer by configuring the past time. */
 911                 rtc_time64_to_tm(t_now - 1, &alarm.time);
 912                 alarm.enabled = 0;
 913                 retval = cmos_set_alarm(dev, &alarm);
 914         } else if (cmos->alarm_expires > t_now + 1) {
 915                 retval = -EBUSY;
 916         }
 917
 918         return retval;
 919 }
 920
 921 static int cmos_suspend(struct device *dev)
 922 {
 923         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 924         unsigned char   tmp;
 925
 926         /* only the alarm might be a wakeup event source */
 927         spin_lock_irq(&rtc_lock);
 928         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 929         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 930                 unsigned char   mask;
 931
 932                 if (device_may_wakeup(dev))
 933                         mask = RTC_IRQMASK & ~RTC_AIE;
 934                 else
 935                         mask = RTC_IRQMASK;
 936                 tmp &= ~mask;
 937                 CMOS_WRITE(tmp, RTC_CONTROL);
 938                 hpet_mask_rtc_irq_bit(mask);
 939
 940                 cmos_checkintr(cmos, tmp);
 941         }
 942         spin_unlock_irq(&rtc_lock);
 943
 944         if (tmp & RTC_AIE) {
 945                 cmos->enabled_wake = 1;
 946                 if (cmos->wake_on)
 947                         cmos->wake_on(dev);
 948                 else
 949                         enable_irq_wake(cmos->irq);
 950         }
 951
 952         cmos_read_alarm(dev, &cmos->saved_wkalrm);
 953
 954         dev_dbg(dev, "suspend%s, ctrl %02x\n",
 955                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
 956                         tmp);
 957
 958         return 0;
 959 }
 960
 961 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
 962  * after a detour through G3 "mechanical off", although the ACPI spec
 963  * says wakeup should only work from G1/S4 "hibernate".  To most users,
 964  * distinctions between S4 and S5 are pointless.  So when the hardware
 965  * allows, don't draw that distinction.
 966  */
 967 static inline int cmos_poweroff(struct device *dev)
 968 {
 969         if (!IS_ENABLED(CONFIG_PM))
 970                 return -ENOSYS;
 971
 972         return cmos_suspend(dev);
 973 }
 974
 975 static void cmos_check_wkalrm(struct device *dev)
 976 {
 977         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 978         struct rtc_wkalrm current_alarm;
 979         time64_t t_current_expires;
 980         time64_t t_saved_expires;
 981
 982         cmos_read_alarm(dev, &current_alarm);
 983         t_current_expires = rtc_tm_to_time64(&current_alarm.time);
 984         t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time);
 985         if (t_current_expires != t_saved_expires ||
 986             cmos->saved_wkalrm.enabled != current_alarm.enabled) {
 987                 cmos_set_alarm(dev, &cmos->saved_wkalrm);
 988         }
 989 }
 990
 991 static void cmos_check_acpi_rtc_status(struct device *dev,
 992                                        unsigned char *rtc_control);
 993
 994 static int __maybe_unused cmos_resume(struct device *dev)
 995 {
 996         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 997         unsigned char tmp;
 998
 999         if (cmos->enabled_wake) {
1000                 if (cmos->wake_off)
1001                         cmos->wake_off(dev);
1002                 else
1003                         disable_irq_wake(cmos->irq);
1004                 cmos->enabled_wake = 0;
1005         }
1006
1007         /* The BIOS might have changed the alarm, restore it */
1008         cmos_check_wkalrm(dev);
1009
1010         spin_lock_irq(&rtc_lock);
1011         tmp = cmos->suspend_ctrl;
1012         cmos->suspend_ctrl = 0;
1013         /* re-enable any irqs previously active */
1014         if (tmp & RTC_IRQMASK) {
1015                 unsigned char   mask;
1016
1017                 if (device_may_wakeup(dev))
1018                         hpet_rtc_timer_init();
1019
1020                 do {
1021                         CMOS_WRITE(tmp, RTC_CONTROL);
1022                         hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
1023
1024                         mask = CMOS_READ(RTC_INTR_FLAGS);
1025                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
1026                         if (!is_hpet_enabled() || !is_intr(mask))
1027                                 break;
1028
1029                         /* force one-shot behavior if HPET blocked
1030                          * the wake alarm's irq
1031                          */
1032                         rtc_update_irq(cmos->rtc, 1, mask);
1033                         tmp &= ~RTC_AIE;
1034                         hpet_mask_rtc_irq_bit(RTC_AIE);
1035                 } while (mask & RTC_AIE);
1036
1037                 if (tmp & RTC_AIE)
1038                         cmos_check_acpi_rtc_status(dev, &tmp);
1039         }
1040         spin_unlock_irq(&rtc_lock);
1041
1042         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1043
1044         return 0;
1045 }
1046
1047 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1048
1049 /*----------------------------------------------------------------*/
1050
1051 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1052  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1053  * probably list them in similar PNPBIOS tables; so PNP is more common.
1054  *
1055  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1056  * predate even PNPBIOS should set up platform_bus devices.
1057  */
1058
1059 #ifdef  CONFIG_ACPI
1060
1061 #include <linux/acpi.h>
1062
1063 static u32 rtc_handler(void *context)
1064 {
1065         struct device *dev = context;
1066         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1067         unsigned char rtc_control = 0;
1068         unsigned char rtc_intr;
1069         unsigned long flags;
1070
1071         spin_lock_irqsave(&rtc_lock, flags);
1072         if (cmos_rtc.suspend_ctrl)
1073                 rtc_control = CMOS_READ(RTC_CONTROL);
1074         if (rtc_control & RTC_AIE) {
1075                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
1076                 CMOS_WRITE(rtc_control, RTC_CONTROL);
1077                 rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
1078                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
1079         }
1080         spin_unlock_irqrestore(&rtc_lock, flags);
1081
1082         pm_wakeup_hard_event(dev);
1083         acpi_clear_event(ACPI_EVENT_RTC);
1084         acpi_disable_event(ACPI_EVENT_RTC, 0);
1085         return ACPI_INTERRUPT_HANDLED;
1086 }
1087
1088 static inline void rtc_wake_setup(struct device *dev)
1089 {
1090         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1091         /*
1092          * After the RTC handler is installed, the Fixed_RTC event should
1093          * be disabled. Only when the RTC alarm is set will it be enabled.
1094          */
1095         acpi_clear_event(ACPI_EVENT_RTC);
1096         acpi_disable_event(ACPI_EVENT_RTC, 0);
1097 }
1098
1099 static void rtc_wake_on(struct device *dev)
1100 {
1101         acpi_clear_event(ACPI_EVENT_RTC);
1102         acpi_enable_event(ACPI_EVENT_RTC, 0);
1103 }
1104
1105 static void rtc_wake_off(struct device *dev)
1106 {
1107         acpi_disable_event(ACPI_EVENT_RTC, 0);
1108 }
1109
1110 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1111  * its device node and pass extra config data.  This helps its driver use
1112  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1113  * that this board's RTC is wakeup-capable (per ACPI spec).
1114  */
1115 static struct cmos_rtc_board_info acpi_rtc_info;
1116
1117 static void cmos_wake_setup(struct device *dev)
1118 {
1119         if (acpi_disabled)
1120                 return;
1121
1122         rtc_wake_setup(dev);
1123         acpi_rtc_info.wake_on = rtc_wake_on;
1124         acpi_rtc_info.wake_off = rtc_wake_off;
1125
1126         /* workaround bug in some ACPI tables */
1127         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1128                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1129                         acpi_gbl_FADT.month_alarm);
1130                 acpi_gbl_FADT.month_alarm = 0;
1131         }
1132
1133         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1134         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1135         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1136
1137         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1138         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1139                 dev_info(dev, "RTC can wake from S4\n");
1140
1141         dev->platform_data = &acpi_rtc_info;
1142
1143         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1144         device_init_wakeup(dev, 1);
1145 }
1146
1147 static void cmos_check_acpi_rtc_status(struct device *dev,
1148                                        unsigned char *rtc_control)
1149 {
1150         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1151         acpi_event_status rtc_status;
1152         acpi_status status;
1153
1154         if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)
1155                 return;
1156
1157         status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);
1158         if (ACPI_FAILURE(status)) {
1159                 dev_err(dev, "Could not get RTC status\n");
1160         } else if (rtc_status & ACPI_EVENT_FLAG_SET) {
1161                 unsigned char mask;
1162                 *rtc_control &= ~RTC_AIE;
1163                 CMOS_WRITE(*rtc_control, RTC_CONTROL);
1164                 mask = CMOS_READ(RTC_INTR_FLAGS);
1165                 rtc_update_irq(cmos->rtc, 1, mask);
1166         }
1167 }
1168
1169 #else
1170
1171 static void cmos_wake_setup(struct device *dev)
1172 {
1173 }
1174
1175 static void cmos_check_acpi_rtc_status(struct device *dev,
1176                                        unsigned char *rtc_control)
1177 {
1178 }
1179
1180 #endif
1181
1182 #ifdef  CONFIG_PNP
1183
1184 #include <linux/pnp.h>
1185
1186 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1187 {
1188         cmos_wake_setup(&pnp->dev);
1189
1190         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0)) {
1191                 unsigned int irq = 0;
1192 #ifdef CONFIG_X86
1193                 /* Some machines contain a PNP entry for the RTC, but
1194                  * don't define the IRQ. It should always be safe to
1195                  * hardcode it on systems with a legacy PIC.
1196                  */
1197                 if (nr_legacy_irqs())
1198                         irq = 8;
1199 #endif
1200                 return cmos_do_probe(&pnp->dev,
1201                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), irq);
1202         } else {
1203                 return cmos_do_probe(&pnp->dev,
1204                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1205                                 pnp_irq(pnp, 0));
1206         }
1207 }
1208
1209 static void cmos_pnp_remove(struct pnp_dev *pnp)
1210 {
1211         cmos_do_remove(&pnp->dev);
1212 }
1213
1214 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1215 {
1216         struct device *dev = &pnp->dev;
1217         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1218
1219         if (system_state == SYSTEM_POWER_OFF) {
1220                 int retval = cmos_poweroff(dev);
1221
1222                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1223                         return;
1224         }
1225
1226         cmos_do_shutdown(cmos->irq);
1227 }
1228
1229 static const struct pnp_device_id rtc_ids[] = {
1230         { .id = "PNP0b00", },
1231         { .id = "PNP0b01", },
1232         { .id = "PNP0b02", },
1233         { },
1234 };
1235 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1236
1237 static struct pnp_driver cmos_pnp_driver = {
1238         .name           = (char *) driver_name,
1239         .id_table       = rtc_ids,
1240         .probe          = cmos_pnp_probe,
1241         .remove         = cmos_pnp_remove,
1242         .shutdown       = cmos_pnp_shutdown,
1243
1244         /* flag ensures resume() gets called, and stops syslog spam */
1245         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1246         .driver         = {
1247                         .pm = &cmos_pm_ops,
1248         },
1249 };
1250
1251 #endif  /* CONFIG_PNP */
1252
1253 #ifdef CONFIG_OF
1254 static const struct of_device_id of_cmos_match[] = {
1255         {
1256                 .compatible = "motorola,mc146818",
1257         },
1258         { },
1259 };
1260 MODULE_DEVICE_TABLE(of, of_cmos_match);
1261
1262 static __init void cmos_of_init(struct platform_device *pdev)
1263 {
1264         struct device_node *node = pdev->dev.of_node;
1265         const __be32 *val;
1266
1267         if (!node)
1268                 return;
1269
1270         val = of_get_property(node, "ctrl-reg", NULL);
1271         if (val)
1272                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1273
1274         val = of_get_property(node, "freq-reg", NULL);
1275         if (val)
1276                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1277 }
1278 #else
1279 static inline void cmos_of_init(struct platform_device *pdev) {}
1280 #endif
1281 /*----------------------------------------------------------------*/
1282
1283 /* Platform setup should have set up an RTC device, when PNP is
1284  * unavailable ... this could happen even on (older) PCs.
1285  */
1286
1287 static int __init cmos_platform_probe(struct platform_device *pdev)
1288 {
1289         struct resource *resource;
1290         int irq;
1291
1292         cmos_of_init(pdev);
1293         cmos_wake_setup(&pdev->dev);
1294
1295         if (RTC_IOMAPPED)
1296                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1297         else
1298                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1299         irq = platform_get_irq(pdev, 0);
1300         if (irq < 0)
1301                 irq = -1;
1302
1303         return cmos_do_probe(&pdev->dev, resource, irq);
1304 }
1305
1306 static int cmos_platform_remove(struct platform_device *pdev)
1307 {
1308         cmos_do_remove(&pdev->dev);
1309         return 0;
1310 }
1311
1312 static void cmos_platform_shutdown(struct platform_device *pdev)
1313 {
1314         struct device *dev = &pdev->dev;
1315         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1316
1317         if (system_state == SYSTEM_POWER_OFF) {
1318                 int retval = cmos_poweroff(dev);
1319
1320                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1321                         return;
1322         }
1323
1324         cmos_do_shutdown(cmos->irq);
1325 }
1326
1327 /* work with hotplug and coldplug */
1328 MODULE_ALIAS("platform:rtc_cmos");
1329
1330 static struct platform_driver cmos_platform_driver = {
1331         .remove         = cmos_platform_remove,
1332         .shutdown       = cmos_platform_shutdown,
1333         .driver = {
1334                 .name           = driver_name,
1335                 .pm             = &cmos_pm_ops,
1336                 .of_match_table = of_match_ptr(of_cmos_match),
1337         }
1338 };
1339
1340 #ifdef CONFIG_PNP
1341 static bool pnp_driver_registered;
1342 #endif
1343 static bool platform_driver_registered;
1344
1345 static int __init cmos_init(void)
1346 {
1347         int retval = 0;
1348
1349 #ifdef  CONFIG_PNP
1350         retval = pnp_register_driver(&cmos_pnp_driver);
1351         if (retval == 0)
1352                 pnp_driver_registered = true;
1353 #endif
1354
1355         if (!cmos_rtc.dev) {
1356                 retval = platform_driver_probe(&cmos_platform_driver,
1357                                                cmos_platform_probe);
1358                 if (retval == 0)
1359                         platform_driver_registered = true;
1360         }
1361
1362         if (retval == 0)
1363                 return 0;
1364
1365 #ifdef  CONFIG_PNP
1366         if (pnp_driver_registered)
1367                 pnp_unregister_driver(&cmos_pnp_driver);
1368 #endif
1369         return retval;
1370 }
1371 module_init(cmos_init);
1372
1373 static void __exit cmos_exit(void)
1374 {
1375 #ifdef  CONFIG_PNP
1376         if (pnp_driver_registered)
1377                 pnp_unregister_driver(&cmos_pnp_driver);
1378 #endif
1379         if (platform_driver_registered)
1380                 platform_driver_unregister(&cmos_platform_driver);
1381 }
1382 module_exit(cmos_exit);
1383
1384
1385 MODULE_AUTHOR("David Brownell");
1386 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1387 MODULE_LICENSE("GPL");