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 #include <linux/dmi.h>
  45
  46 /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
  47 #include <asm-generic/rtc.h>
  48
  49 struct cmos_rtc {
  50         struct rtc_device       *rtc;
  51         struct device           *dev;
  52         int                     irq;
  53         struct resource         *iomem;
  54         time64_t                alarm_expires;
  55
  56         void                    (*wake_on)(struct device *);
  57         void                    (*wake_off)(struct device *);
  58
  59         u8                      enabled_wake;
  60         u8                      suspend_ctrl;
  61
  62         /* newer hardware extends the original register set */
  63         u8                      day_alrm;
  64         u8                      mon_alrm;
  65         u8                      century;
  66 };
  67
  68 /* both platform and pnp busses use negative numbers for invalid irqs */
  69 #define is_valid_irq(n)         ((n) > 0)
  70
  71 static const char driver_name[] = "rtc_cmos";
  72
  73 /* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
  74  * always mask it against the irq enable bits in RTC_CONTROL.  Bit values
  75  * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
  76  */
  77 #define RTC_IRQMASK     (RTC_PF | RTC_AF | RTC_UF)
  78
  79 static inline int is_intr(u8 rtc_intr)
  80 {
  81         if (!(rtc_intr & RTC_IRQF))
  82                 return 0;
  83         return rtc_intr & RTC_IRQMASK;
  84 }
  85
  86 /*----------------------------------------------------------------*/
  87
  88 /* Much modern x86 hardware has HPETs (10+ MHz timers) which, because
  89  * many BIOS programmers don't set up "sane mode" IRQ routing, are mostly
  90  * used in a broken "legacy replacement" mode.  The breakage includes
  91  * HPET #1 hijacking the IRQ for this RTC, and being unavailable for
  92  * other (better) use.
  93  *
  94  * When that broken mode is in use, platform glue provides a partial
  95  * emulation of hardware RTC IRQ facilities using HPET #1.  We don't
  96  * want to use HPET for anything except those IRQs though...
  97  */
  98 #ifdef CONFIG_HPET_EMULATE_RTC
  99 #include <asm/hpet.h>
 100 #else
 101
 102 static inline int is_hpet_enabled(void)
 103 {
 104         return 0;
 105 }
 106
 107 static inline int hpet_mask_rtc_irq_bit(unsigned long mask)
 108 {
 109         return 0;
 110 }
 111
 112 static inline int hpet_set_rtc_irq_bit(unsigned long mask)
 113 {
 114         return 0;
 115 }
 116
 117 static inline int
 118 hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
 119 {
 120         return 0;
 121 }
 122
 123 static inline int hpet_set_periodic_freq(unsigned long freq)
 124 {
 125         return 0;
 126 }
 127
 128 static inline int hpet_rtc_dropped_irq(void)
 129 {
 130         return 0;
 131 }
 132
 133 static inline int hpet_rtc_timer_init(void)
 134 {
 135         return 0;
 136 }
 137
 138 extern irq_handler_t hpet_rtc_interrupt;
 139
 140 static inline int hpet_register_irq_handler(irq_handler_t handler)
 141 {
 142         return 0;
 143 }
 144
 145 static inline int hpet_unregister_irq_handler(irq_handler_t handler)
 146 {
 147         return 0;
 148 }
 149
 150 #endif
 151
 152 /*----------------------------------------------------------------*/
 153
 154 #ifdef RTC_PORT
 155
 156 /* Most newer x86 systems have two register banks, the first used
 157  * for RTC and NVRAM and the second only for NVRAM.  Caller must
 158  * own rtc_lock ... and we won't worry about access during NMI.
 159  */
 160 #define can_bank2       true
 161
 162 static inline unsigned char cmos_read_bank2(unsigned char addr)
 163 {
 164         outb(addr, RTC_PORT(2));
 165         return inb(RTC_PORT(3));
 166 }
 167
 168 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 169 {
 170         outb(addr, RTC_PORT(2));
 171         outb(val, RTC_PORT(3));
 172 }
 173
 174 #else
 175
 176 #define can_bank2       false
 177
 178 static inline unsigned char cmos_read_bank2(unsigned char addr)
 179 {
 180         return 0;
 181 }
 182
 183 static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 184 {
 185 }
 186
 187 #endif
 188
 189 /*----------------------------------------------------------------*/
 190
 191 static int cmos_read_time(struct device *dev, struct rtc_time *t)
 192 {
 193         /* REVISIT:  if the clock has a "century" register, use
 194          * that instead of the heuristic in get_rtc_time().
 195          * That'll make Y3K compatility (year > 2070) easy!
 196          */
 197         get_rtc_time(t);
 198         return 0;
 199 }
 200
 201 static int cmos_set_time(struct device *dev, struct rtc_time *t)
 202 {
 203         /* REVISIT:  set the "century" register if available
 204          *
 205          * NOTE: this ignores the issue whereby updating the seconds
 206          * takes effect exactly 500ms after we write the register.
 207          * (Also queueing and other delays before we get this far.)
 208          */
 209         return set_rtc_time(t);
 210 }
 211
 212 static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 213 {
 214         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 215         unsigned char   rtc_control;
 216
 217         if (!is_valid_irq(cmos->irq))
 218                 return -EIO;
 219
 220         /* Basic alarms only support hour, minute, and seconds fields.
 221          * Some also support day and month, for alarms up to a year in
 222          * the future.
 223          */
 224         t->time.tm_mday = -1;
 225         t->time.tm_mon = -1;
 226
 227         spin_lock_irq(&rtc_lock);
 228         t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
 229         t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
 230         t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
 231
 232         if (cmos->day_alrm) {
 233                 /* ignore upper bits on readback per ACPI spec */
 234                 t->time.tm_mday = CMOS_READ(cmos->day_alrm) & 0x3f;
 235                 if (!t->time.tm_mday)
 236                         t->time.tm_mday = -1;
 237
 238                 if (cmos->mon_alrm) {
 239                         t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
 240                         if (!t->time.tm_mon)
 241                                 t->time.tm_mon = -1;
 242                 }
 243         }
 244
 245         rtc_control = CMOS_READ(RTC_CONTROL);
 246         spin_unlock_irq(&rtc_lock);
 247
 248         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 249                 if (((unsigned)t->time.tm_sec) < 0x60)
 250                         t->time.tm_sec = bcd2bin(t->time.tm_sec);
 251                 else
 252                         t->time.tm_sec = -1;
 253                 if (((unsigned)t->time.tm_min) < 0x60)
 254                         t->time.tm_min = bcd2bin(t->time.tm_min);
 255                 else
 256                         t->time.tm_min = -1;
 257                 if (((unsigned)t->time.tm_hour) < 0x24)
 258                         t->time.tm_hour = bcd2bin(t->time.tm_hour);
 259                 else
 260                         t->time.tm_hour = -1;
 261
 262                 if (cmos->day_alrm) {
 263                         if (((unsigned)t->time.tm_mday) <= 0x31)
 264                                 t->time.tm_mday = bcd2bin(t->time.tm_mday);
 265                         else
 266                                 t->time.tm_mday = -1;
 267
 268                         if (cmos->mon_alrm) {
 269                                 if (((unsigned)t->time.tm_mon) <= 0x12)
 270                                         t->time.tm_mon = bcd2bin(t->time.tm_mon)-1;
 271                                 else
 272                                         t->time.tm_mon = -1;
 273                         }
 274                 }
 275         }
 276         t->time.tm_year = -1;
 277
 278         t->enabled = !!(rtc_control & RTC_AIE);
 279         t->pending = 0;
 280
 281         return 0;
 282 }
 283
 284 static void cmos_checkintr(struct cmos_rtc *cmos, unsigned char rtc_control)
 285 {
 286         unsigned char   rtc_intr;
 287
 288         /* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
 289          * allegedly some older rtcs need that to handle irqs properly
 290          */
 291         rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
 292
 293         if (is_hpet_enabled())
 294                 return;
 295
 296         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 297         if (is_intr(rtc_intr))
 298                 rtc_update_irq(cmos->rtc, 1, rtc_intr);
 299 }
 300
 301 static void cmos_irq_enable(struct cmos_rtc *cmos, unsigned char mask)
 302 {
 303         unsigned char   rtc_control;
 304
 305         /* flush any pending IRQ status, notably for update irqs,
 306          * before we enable new IRQs
 307          */
 308         rtc_control = CMOS_READ(RTC_CONTROL);
 309         cmos_checkintr(cmos, rtc_control);
 310
 311         rtc_control |= mask;
 312         CMOS_WRITE(rtc_control, RTC_CONTROL);
 313         hpet_set_rtc_irq_bit(mask);
 314
 315         cmos_checkintr(cmos, rtc_control);
 316 }
 317
 318 static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 319 {
 320         unsigned char   rtc_control;
 321
 322         rtc_control = CMOS_READ(RTC_CONTROL);
 323         rtc_control &= ~mask;
 324         CMOS_WRITE(rtc_control, RTC_CONTROL);
 325         hpet_mask_rtc_irq_bit(mask);
 326
 327         cmos_checkintr(cmos, rtc_control);
 328 }
 329
 330 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 331 {
 332         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 333         unsigned char mon, mday, hrs, min, sec, rtc_control;
 334
 335         if (!is_valid_irq(cmos->irq))
 336                 return -EIO;
 337
 338         mon = t->time.tm_mon + 1;
 339         mday = t->time.tm_mday;
 340         hrs = t->time.tm_hour;
 341         min = t->time.tm_min;
 342         sec = t->time.tm_sec;
 343
 344         rtc_control = CMOS_READ(RTC_CONTROL);
 345         if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 346                 /* Writing 0xff means "don't care" or "match all".  */
 347                 mon = (mon <= 12) ? bin2bcd(mon) : 0xff;
 348                 mday = (mday >= 1 && mday <= 31) ? bin2bcd(mday) : 0xff;
 349                 hrs = (hrs < 24) ? bin2bcd(hrs) : 0xff;
 350                 min = (min < 60) ? bin2bcd(min) : 0xff;
 351                 sec = (sec < 60) ? bin2bcd(sec) : 0xff;
 352         }
 353
 354         spin_lock_irq(&rtc_lock);
 355
 356         /* next rtc irq must not be from previous alarm setting */
 357         cmos_irq_disable(cmos, RTC_AIE);
 358
 359         /* update alarm */
 360         CMOS_WRITE(hrs, RTC_HOURS_ALARM);
 361         CMOS_WRITE(min, RTC_MINUTES_ALARM);
 362         CMOS_WRITE(sec, RTC_SECONDS_ALARM);
 363
 364         /* the system may support an "enhanced" alarm */
 365         if (cmos->day_alrm) {
 366                 CMOS_WRITE(mday, cmos->day_alrm);
 367                 if (cmos->mon_alrm)
 368                         CMOS_WRITE(mon, cmos->mon_alrm);
 369         }
 370
 371         /* FIXME the HPET alarm glue currently ignores day_alrm
 372          * and mon_alrm ...
 373          */
 374         hpet_set_alarm_time(t->time.tm_hour, t->time.tm_min, t->time.tm_sec);
 375
 376         if (t->enabled)
 377                 cmos_irq_enable(cmos, RTC_AIE);
 378
 379         spin_unlock_irq(&rtc_lock);
 380
 381         cmos->alarm_expires = rtc_tm_to_time64(&t->time);
 382
 383         return 0;
 384 }
 385
 386 /*
 387  * Do not disable RTC alarm on shutdown - workaround for b0rked BIOSes.
 388  */
 389 static bool alarm_disable_quirk;
 390
 391 static int __init set_alarm_disable_quirk(const struct dmi_system_id *id)
 392 {
 393         alarm_disable_quirk = true;
 394         pr_info("BIOS has alarm-disable quirk - RTC alarms disabled\n");
 395         return 0;
 396 }
 397
 398 static const struct dmi_system_id rtc_quirks[] __initconst = {
 399         /* https://bugzilla.novell.com/show_bug.cgi?id=805740 */
 400         {
 401                 .callback = set_alarm_disable_quirk,
 402                 .ident    = "IBM Truman",
 403                 .matches  = {
 404                         DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
 405                         DMI_MATCH(DMI_PRODUCT_NAME, "4852570"),
 406                 },
 407         },
 408         /* https://bugzilla.novell.com/show_bug.cgi?id=812592 */
 409         {
 410                 .callback = set_alarm_disable_quirk,
 411                 .ident    = "Gigabyte GA-990XA-UD3",
 412                 .matches  = {
 413                         DMI_MATCH(DMI_SYS_VENDOR,
 414                                         "Gigabyte Technology Co., Ltd."),
 415                         DMI_MATCH(DMI_PRODUCT_NAME, "GA-990XA-UD3"),
 416                 },
 417         },
 418         /* http://permalink.gmane.org/gmane.linux.kernel/1604474 */
 419         {
 420                 .callback = set_alarm_disable_quirk,
 421                 .ident    = "Toshiba Satellite L300",
 422                 .matches  = {
 423                         DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
 424                         DMI_MATCH(DMI_PRODUCT_NAME, "Satellite L300"),
 425                 },
 426         },
 427         {}
 428 };
 429
 430 static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
 431 {
 432         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 433         unsigned long   flags;
 434
 435         if (!is_valid_irq(cmos->irq))
 436                 return -EINVAL;
 437
 438         if (alarm_disable_quirk)
 439                 return 0;
 440
 441         spin_lock_irqsave(&rtc_lock, flags);
 442
 443         if (enabled)
 444                 cmos_irq_enable(cmos, RTC_AIE);
 445         else
 446                 cmos_irq_disable(cmos, RTC_AIE);
 447
 448         spin_unlock_irqrestore(&rtc_lock, flags);
 449         return 0;
 450 }
 451
 452 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
 453
 454 static int cmos_procfs(struct device *dev, struct seq_file *seq)
 455 {
 456         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 457         unsigned char   rtc_control, valid;
 458
 459         spin_lock_irq(&rtc_lock);
 460         rtc_control = CMOS_READ(RTC_CONTROL);
 461         valid = CMOS_READ(RTC_VALID);
 462         spin_unlock_irq(&rtc_lock);
 463
 464         /* NOTE:  at least ICH6 reports battery status using a different
 465          * (non-RTC) bit; and SQWE is ignored on many current systems.
 466          */
 467         seq_printf(seq,
 468                    "periodic_IRQ\t: %s\n"
 469                    "update_IRQ\t: %s\n"
 470                    "HPET_emulated\t: %s\n"
 471                    // "square_wave\t: %s\n"
 472                    "BCD\t\t: %s\n"
 473                    "DST_enable\t: %s\n"
 474                    "periodic_freq\t: %d\n"
 475                    "batt_status\t: %s\n",
 476                    (rtc_control & RTC_PIE) ? "yes" : "no",
 477                    (rtc_control & RTC_UIE) ? "yes" : "no",
 478                    is_hpet_enabled() ? "yes" : "no",
 479                    // (rtc_control & RTC_SQWE) ? "yes" : "no",
 480                    (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
 481                    (rtc_control & RTC_DST_EN) ? "yes" : "no",
 482                    cmos->rtc->irq_freq,
 483                    (valid & RTC_VRT) ? "okay" : "dead");
 484
 485         return 0;
 486 }
 487
 488 #else
 489 #define cmos_procfs     NULL
 490 #endif
 491
 492 static const struct rtc_class_ops cmos_rtc_ops = {
 493         .read_time              = cmos_read_time,
 494         .set_time               = cmos_set_time,
 495         .read_alarm             = cmos_read_alarm,
 496         .set_alarm              = cmos_set_alarm,
 497         .proc                   = cmos_procfs,
 498         .alarm_irq_enable       = cmos_alarm_irq_enable,
 499 };
 500
 501 /*----------------------------------------------------------------*/
 502
 503 /*
 504  * All these chips have at least 64 bytes of address space, shared by
 505  * RTC registers and NVRAM.  Most of those bytes of NVRAM are used
 506  * by boot firmware.  Modern chips have 128 or 256 bytes.
 507  */
 508
 509 #define NVRAM_OFFSET    (RTC_REG_D + 1)
 510
 511 static ssize_t
 512 cmos_nvram_read(struct file *filp, struct kobject *kobj,
 513                 struct bin_attribute *attr,
 514                 char *buf, loff_t off, size_t count)
 515 {
 516         int     retval;
 517
 518         if (unlikely(off >= attr->size))
 519                 return 0;
 520         if (unlikely(off < 0))
 521                 return -EINVAL;
 522         if ((off + count) > attr->size)
 523                 count = attr->size - off;
 524
 525         off += NVRAM_OFFSET;
 526         spin_lock_irq(&rtc_lock);
 527         for (retval = 0; count; count--, off++, retval++) {
 528                 if (off < 128)
 529                         *buf++ = CMOS_READ(off);
 530                 else if (can_bank2)
 531                         *buf++ = cmos_read_bank2(off);
 532                 else
 533                         break;
 534         }
 535         spin_unlock_irq(&rtc_lock);
 536
 537         return retval;
 538 }
 539
 540 static ssize_t
 541 cmos_nvram_write(struct file *filp, struct kobject *kobj,
 542                 struct bin_attribute *attr,
 543                 char *buf, loff_t off, size_t count)
 544 {
 545         struct cmos_rtc *cmos;
 546         int             retval;
 547
 548         cmos = dev_get_drvdata(container_of(kobj, struct device, kobj));
 549         if (unlikely(off >= attr->size))
 550                 return -EFBIG;
 551         if (unlikely(off < 0))
 552                 return -EINVAL;
 553         if ((off + count) > attr->size)
 554                 count = attr->size - off;
 555
 556         /* NOTE:  on at least PCs and Ataris, the boot firmware uses a
 557          * checksum on part of the NVRAM data.  That's currently ignored
 558          * here.  If userspace is smart enough to know what fields of
 559          * NVRAM to update, updating checksums is also part of its job.
 560          */
 561         off += NVRAM_OFFSET;
 562         spin_lock_irq(&rtc_lock);
 563         for (retval = 0; count; count--, off++, retval++) {
 564                 /* don't trash RTC registers */
 565                 if (off == cmos->day_alrm
 566                                 || off == cmos->mon_alrm
 567                                 || off == cmos->century)
 568                         buf++;
 569                 else if (off < 128)
 570                         CMOS_WRITE(*buf++, off);
 571                 else if (can_bank2)
 572                         cmos_write_bank2(*buf++, off);
 573                 else
 574                         break;
 575         }
 576         spin_unlock_irq(&rtc_lock);
 577
 578         return retval;
 579 }
 580
 581 static struct bin_attribute nvram = {
 582         .attr = {
 583                 .name   = "nvram",
 584                 .mode   = S_IRUGO | S_IWUSR,
 585         },
 586
 587         .read   = cmos_nvram_read,
 588         .write  = cmos_nvram_write,
 589         /* size gets set up later */
 590 };
 591
 592 /*----------------------------------------------------------------*/
 593
 594 static struct cmos_rtc  cmos_rtc;
 595
 596 static irqreturn_t cmos_interrupt(int irq, void *p)
 597 {
 598         u8              irqstat;
 599         u8              rtc_control;
 600
 601         spin_lock(&rtc_lock);
 602
 603         /* When the HPET interrupt handler calls us, the interrupt
 604          * status is passed as arg1 instead of the irq number.  But
 605          * always clear irq status, even when HPET is in the way.
 606          *
 607          * Note that HPET and RTC are almost certainly out of phase,
 608          * giving different IRQ status ...
 609          */
 610         irqstat = CMOS_READ(RTC_INTR_FLAGS);
 611         rtc_control = CMOS_READ(RTC_CONTROL);
 612         if (is_hpet_enabled())
 613                 irqstat = (unsigned long)irq & 0xF0;
 614
 615         /* If we were suspended, RTC_CONTROL may not be accurate since the
 616          * bios may have cleared it.
 617          */
 618         if (!cmos_rtc.suspend_ctrl)
 619                 irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
 620         else
 621                 irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
 622
 623         /* All Linux RTC alarms should be treated as if they were oneshot.
 624          * Similar code may be needed in system wakeup paths, in case the
 625          * alarm woke the system.
 626          */
 627         if (irqstat & RTC_AIE) {
 628                 cmos_rtc.suspend_ctrl &= ~RTC_AIE;
 629                 rtc_control &= ~RTC_AIE;
 630                 CMOS_WRITE(rtc_control, RTC_CONTROL);
 631                 hpet_mask_rtc_irq_bit(RTC_AIE);
 632                 CMOS_READ(RTC_INTR_FLAGS);
 633         }
 634         spin_unlock(&rtc_lock);
 635
 636         if (is_intr(irqstat)) {
 637                 rtc_update_irq(p, 1, irqstat);
 638                 return IRQ_HANDLED;
 639         } else
 640                 return IRQ_NONE;
 641 }
 642
 643 #ifdef  CONFIG_PNP
 644 #define INITSECTION
 645
 646 #else
 647 #define INITSECTION     __init
 648 #endif
 649
 650 static int INITSECTION
 651 cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 652 {
 653         struct cmos_rtc_board_info      *info = dev_get_platdata(dev);
 654         int                             retval = 0;
 655         unsigned char                   rtc_control;
 656         unsigned                        address_space;
 657         u32                             flags = 0;
 658
 659         /* there can be only one ... */
 660         if (cmos_rtc.dev)
 661                 return -EBUSY;
 662
 663         if (!ports)
 664                 return -ENODEV;
 665
 666         /* Claim I/O ports ASAP, minimizing conflict with legacy driver.
 667          *
 668          * REVISIT non-x86 systems may instead use memory space resources
 669          * (needing ioremap etc), not i/o space resources like this ...
 670          */
 671         if (RTC_IOMAPPED)
 672                 ports = request_region(ports->start, resource_size(ports),
 673                                        driver_name);
 674         else
 675                 ports = request_mem_region(ports->start, resource_size(ports),
 676                                            driver_name);
 677         if (!ports) {
 678                 dev_dbg(dev, "i/o registers already in use\n");
 679                 return -EBUSY;
 680         }
 681
 682         cmos_rtc.irq = rtc_irq;
 683         cmos_rtc.iomem = ports;
 684
 685         /* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
 686          * driver did, but don't reject unknown configs.   Old hardware
 687          * won't address 128 bytes.  Newer chips have multiple banks,
 688          * though they may not be listed in one I/O resource.
 689          */
 690 #if     defined(CONFIG_ATARI)
 691         address_space = 64;
 692 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
 693                         || defined(__sparc__) || defined(__mips__) \
 694                         || defined(__powerpc__)
 695         address_space = 128;
 696 #else
 697 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
 698         address_space = 128;
 699 #endif
 700         if (can_bank2 && ports->end > (ports->start + 1))
 701                 address_space = 256;
 702
 703         /* For ACPI systems extension info comes from the FADT.  On others,
 704          * board specific setup provides it as appropriate.  Systems where
 705          * the alarm IRQ isn't automatically a wakeup IRQ (like ACPI, and
 706          * some almost-clones) can provide hooks to make that behave.
 707          *
 708          * Note that ACPI doesn't preclude putting these registers into
 709          * "extended" areas of the chip, including some that we won't yet
 710          * expect CMOS_READ and friends to handle.
 711          */
 712         if (info) {
 713                 if (info->flags)
 714                         flags = info->flags;
 715                 if (info->address_space)
 716                         address_space = info->address_space;
 717
 718                 if (info->rtc_day_alarm && info->rtc_day_alarm < 128)
 719                         cmos_rtc.day_alrm = info->rtc_day_alarm;
 720                 if (info->rtc_mon_alarm && info->rtc_mon_alarm < 128)
 721                         cmos_rtc.mon_alrm = info->rtc_mon_alarm;
 722                 if (info->rtc_century && info->rtc_century < 128)
 723                         cmos_rtc.century = info->rtc_century;
 724
 725                 if (info->wake_on && info->wake_off) {
 726                         cmos_rtc.wake_on = info->wake_on;
 727                         cmos_rtc.wake_off = info->wake_off;
 728                 }
 729         }
 730
 731         cmos_rtc.dev = dev;
 732         dev_set_drvdata(dev, &cmos_rtc);
 733
 734         cmos_rtc.rtc = rtc_device_register(driver_name, dev,
 735                                 &cmos_rtc_ops, THIS_MODULE);
 736         if (IS_ERR(cmos_rtc.rtc)) {
 737                 retval = PTR_ERR(cmos_rtc.rtc);
 738                 goto cleanup0;
 739         }
 740
 741         rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 742
 743         spin_lock_irq(&rtc_lock);
 744
 745         if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 746                 /* force periodic irq to CMOS reset default of 1024Hz;
 747                  *
 748                  * REVISIT it's been reported that at least one x86_64 ALI
 749                  * mobo doesn't use 32KHz here ... for portability we might
 750                  * need to do something about other clock frequencies.
 751                  */
 752                 cmos_rtc.rtc->irq_freq = 1024;
 753                 hpet_set_periodic_freq(cmos_rtc.rtc->irq_freq);
 754                 CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
 755         }
 756
 757         /* disable irqs */
 758         if (is_valid_irq(rtc_irq))
 759                 cmos_irq_disable(&cmos_rtc, RTC_PIE | RTC_AIE | RTC_UIE);
 760
 761         rtc_control = CMOS_READ(RTC_CONTROL);
 762
 763         spin_unlock_irq(&rtc_lock);
 764
 765         /* FIXME:
 766          * <asm-generic/rtc.h> doesn't know 12-hour mode either.
 767          */
 768         if (is_valid_irq(rtc_irq) && !(rtc_control & RTC_24H)) {
 769                 dev_warn(dev, "only 24-hr supported\n");
 770                 retval = -ENXIO;
 771                 goto cleanup1;
 772         }
 773
 774         if (is_valid_irq(rtc_irq)) {
 775                 irq_handler_t rtc_cmos_int_handler;
 776
 777                 if (is_hpet_enabled()) {
 778                         rtc_cmos_int_handler = hpet_rtc_interrupt;
 779                         retval = hpet_register_irq_handler(cmos_interrupt);
 780                         if (retval) {
 781                                 dev_warn(dev, "hpet_register_irq_handler "
 782                                                 " failed in rtc_init().");
 783                                 goto cleanup1;
 784                         }
 785                 } else
 786                         rtc_cmos_int_handler = cmos_interrupt;
 787
 788                 retval = request_irq(rtc_irq, rtc_cmos_int_handler,
 789                                 0, dev_name(&cmos_rtc.rtc->dev),
 790                                 cmos_rtc.rtc);
 791                 if (retval < 0) {
 792                         dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
 793                         goto cleanup1;
 794                 }
 795         }
 796         hpet_rtc_timer_init();
 797
 798         /* export at least the first block of NVRAM */
 799         nvram.size = address_space - NVRAM_OFFSET;
 800         retval = sysfs_create_bin_file(&dev->kobj, &nvram);
 801         if (retval < 0) {
 802                 dev_dbg(dev, "can't create nvram file? %d\n", retval);
 803                 goto cleanup2;
 804         }
 805
 806         dev_info(dev, "%s%s, %zd bytes nvram%s\n",
 807                 !is_valid_irq(rtc_irq) ? "no alarms" :
 808                         cmos_rtc.mon_alrm ? "alarms up to one year" :
 809                         cmos_rtc.day_alrm ? "alarms up to one month" :
 810                         "alarms up to one day",
 811                 cmos_rtc.century ? ", y3k" : "",
 812                 nvram.size,
 813                 is_hpet_enabled() ? ", hpet irqs" : "");
 814
 815         return 0;
 816
 817 cleanup2:
 818         if (is_valid_irq(rtc_irq))
 819                 free_irq(rtc_irq, cmos_rtc.rtc);
 820 cleanup1:
 821         cmos_rtc.dev = NULL;
 822         rtc_device_unregister(cmos_rtc.rtc);
 823 cleanup0:
 824         if (RTC_IOMAPPED)
 825                 release_region(ports->start, resource_size(ports));
 826         else
 827                 release_mem_region(ports->start, resource_size(ports));
 828         return retval;
 829 }
 830
 831 static void cmos_do_shutdown(int rtc_irq)
 832 {
 833         spin_lock_irq(&rtc_lock);
 834         if (is_valid_irq(rtc_irq))
 835                 cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
 836         spin_unlock_irq(&rtc_lock);
 837 }
 838
 839 static void __exit cmos_do_remove(struct device *dev)
 840 {
 841         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 842         struct resource *ports;
 843
 844         cmos_do_shutdown(cmos->irq);
 845
 846         sysfs_remove_bin_file(&dev->kobj, &nvram);
 847
 848         if (is_valid_irq(cmos->irq)) {
 849                 free_irq(cmos->irq, cmos->rtc);
 850                 hpet_unregister_irq_handler(cmos_interrupt);
 851         }
 852
 853         rtc_device_unregister(cmos->rtc);
 854         cmos->rtc = NULL;
 855
 856         ports = cmos->iomem;
 857         if (RTC_IOMAPPED)
 858                 release_region(ports->start, resource_size(ports));
 859         else
 860                 release_mem_region(ports->start, resource_size(ports));
 861         cmos->iomem = NULL;
 862
 863         cmos->dev = NULL;
 864 }
 865
 866 static int cmos_aie_poweroff(struct device *dev)
 867 {
 868         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 869         struct rtc_time now;
 870         time64_t t_now;
 871         int retval = 0;
 872         unsigned char rtc_control;
 873
 874         if (!cmos->alarm_expires)
 875                 return -EINVAL;
 876
 877         spin_lock_irq(&rtc_lock);
 878         rtc_control = CMOS_READ(RTC_CONTROL);
 879         spin_unlock_irq(&rtc_lock);
 880
 881         /* We only care about the situation where AIE is disabled. */
 882         if (rtc_control & RTC_AIE)
 883                 return -EBUSY;
 884
 885         cmos_read_time(dev, &now);
 886         t_now = rtc_tm_to_time64(&now);
 887
 888         /*
 889          * When enabling "RTC wake-up" in BIOS setup, the machine reboots
 890          * automatically right after shutdown on some buggy boxes.
 891          * This automatic rebooting issue won't happen when the alarm
 892          * time is larger than now+1 seconds.
 893          *
 894          * If the alarm time is equal to now+1 seconds, the issue can be
 895          * prevented by cancelling the alarm.
 896          */
 897         if (cmos->alarm_expires == t_now + 1) {
 898                 struct rtc_wkalrm alarm;
 899
 900                 /* Cancel the AIE timer by configuring the past time. */
 901                 rtc_time64_to_tm(t_now - 1, &alarm.time);
 902                 alarm.enabled = 0;
 903                 retval = cmos_set_alarm(dev, &alarm);
 904         } else if (cmos->alarm_expires > t_now + 1) {
 905                 retval = -EBUSY;
 906         }
 907
 908         return retval;
 909 }
 910
 911 #ifdef CONFIG_PM
 912
 913 static int cmos_suspend(struct device *dev)
 914 {
 915         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 916         unsigned char   tmp;
 917
 918         /* only the alarm might be a wakeup event source */
 919         spin_lock_irq(&rtc_lock);
 920         cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
 921         if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
 922                 unsigned char   mask;
 923
 924                 if (device_may_wakeup(dev))
 925                         mask = RTC_IRQMASK & ~RTC_AIE;
 926                 else
 927                         mask = RTC_IRQMASK;
 928                 tmp &= ~mask;
 929                 CMOS_WRITE(tmp, RTC_CONTROL);
 930                 hpet_mask_rtc_irq_bit(mask);
 931
 932                 cmos_checkintr(cmos, tmp);
 933         }
 934         spin_unlock_irq(&rtc_lock);
 935
 936         if (tmp & RTC_AIE) {
 937                 cmos->enabled_wake = 1;
 938                 if (cmos->wake_on)
 939                         cmos->wake_on(dev);
 940                 else
 941                         enable_irq_wake(cmos->irq);
 942         }
 943
 944         dev_dbg(dev, "suspend%s, ctrl %02x\n",
 945                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
 946                         tmp);
 947
 948         return 0;
 949 }
 950
 951 /* We want RTC alarms to wake us from e.g. ACPI G2/S5 "soft off", even
 952  * after a detour through G3 "mechanical off", although the ACPI spec
 953  * says wakeup should only work from G1/S4 "hibernate".  To most users,
 954  * distinctions between S4 and S5 are pointless.  So when the hardware
 955  * allows, don't draw that distinction.
 956  */
 957 static inline int cmos_poweroff(struct device *dev)
 958 {
 959         return cmos_suspend(dev);
 960 }
 961
 962 #ifdef  CONFIG_PM_SLEEP
 963
 964 static int cmos_resume(struct device *dev)
 965 {
 966         struct cmos_rtc *cmos = dev_get_drvdata(dev);
 967         unsigned char tmp;
 968
 969         if (cmos->enabled_wake) {
 970                 if (cmos->wake_off)
 971                         cmos->wake_off(dev);
 972                 else
 973                         disable_irq_wake(cmos->irq);
 974                 cmos->enabled_wake = 0;
 975         }
 976
 977         spin_lock_irq(&rtc_lock);
 978         tmp = cmos->suspend_ctrl;
 979         cmos->suspend_ctrl = 0;
 980         /* re-enable any irqs previously active */
 981         if (tmp & RTC_IRQMASK) {
 982                 unsigned char   mask;
 983
 984                 if (device_may_wakeup(dev))
 985                         hpet_rtc_timer_init();
 986
 987                 do {
 988                         CMOS_WRITE(tmp, RTC_CONTROL);
 989                         hpet_set_rtc_irq_bit(tmp & RTC_IRQMASK);
 990
 991                         mask = CMOS_READ(RTC_INTR_FLAGS);
 992                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
 993                         if (!is_hpet_enabled() || !is_intr(mask))
 994                                 break;
 995
 996                         /* force one-shot behavior if HPET blocked
 997                          * the wake alarm's irq
 998                          */
 999                         rtc_update_irq(cmos->rtc, 1, mask);
1000                         tmp &= ~RTC_AIE;
1001                         hpet_mask_rtc_irq_bit(RTC_AIE);
1002                 } while (mask & RTC_AIE);
1003         }
1004         spin_unlock_irq(&rtc_lock);
1005
1006         dev_dbg(dev, "resume, ctrl %02x\n", tmp);
1007
1008         return 0;
1009 }
1010
1011 #endif
1012 #else
1013
1014 static inline int cmos_poweroff(struct device *dev)
1015 {
1016         return -ENOSYS;
1017 }
1018
1019 #endif
1020
1021 static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume);
1022
1023 /*----------------------------------------------------------------*/
1024
1025 /* On non-x86 systems, a "CMOS" RTC lives most naturally on platform_bus.
1026  * ACPI systems always list these as PNPACPI devices, and pre-ACPI PCs
1027  * probably list them in similar PNPBIOS tables; so PNP is more common.
1028  *
1029  * We don't use legacy "poke at the hardware" probing.  Ancient PCs that
1030  * predate even PNPBIOS should set up platform_bus devices.
1031  */
1032
1033 #ifdef  CONFIG_ACPI
1034
1035 #include <linux/acpi.h>
1036
1037 static u32 rtc_handler(void *context)
1038 {
1039         struct device *dev = context;
1040
1041         pm_wakeup_event(dev, 0);
1042         acpi_clear_event(ACPI_EVENT_RTC);
1043         acpi_disable_event(ACPI_EVENT_RTC, 0);
1044         return ACPI_INTERRUPT_HANDLED;
1045 }
1046
1047 static inline void rtc_wake_setup(struct device *dev)
1048 {
1049         acpi_install_fixed_event_handler(ACPI_EVENT_RTC, rtc_handler, dev);
1050         /*
1051          * After the RTC handler is installed, the Fixed_RTC event should
1052          * be disabled. Only when the RTC alarm is set will it be enabled.
1053          */
1054         acpi_clear_event(ACPI_EVENT_RTC);
1055         acpi_disable_event(ACPI_EVENT_RTC, 0);
1056 }
1057
1058 static void rtc_wake_on(struct device *dev)
1059 {
1060         acpi_clear_event(ACPI_EVENT_RTC);
1061         acpi_enable_event(ACPI_EVENT_RTC, 0);
1062 }
1063
1064 static void rtc_wake_off(struct device *dev)
1065 {
1066         acpi_disable_event(ACPI_EVENT_RTC, 0);
1067 }
1068
1069 /* Every ACPI platform has a mc146818 compatible "cmos rtc".  Here we find
1070  * its device node and pass extra config data.  This helps its driver use
1071  * capabilities that the now-obsolete mc146818 didn't have, and informs it
1072  * that this board's RTC is wakeup-capable (per ACPI spec).
1073  */
1074 static struct cmos_rtc_board_info acpi_rtc_info;
1075
1076 static void cmos_wake_setup(struct device *dev)
1077 {
1078         if (acpi_disabled)
1079                 return;
1080
1081         rtc_wake_setup(dev);
1082         acpi_rtc_info.wake_on = rtc_wake_on;
1083         acpi_rtc_info.wake_off = rtc_wake_off;
1084
1085         /* workaround bug in some ACPI tables */
1086         if (acpi_gbl_FADT.month_alarm && !acpi_gbl_FADT.day_alarm) {
1087                 dev_dbg(dev, "bogus FADT month_alarm (%d)\n",
1088                         acpi_gbl_FADT.month_alarm);
1089                 acpi_gbl_FADT.month_alarm = 0;
1090         }
1091
1092         acpi_rtc_info.rtc_day_alarm = acpi_gbl_FADT.day_alarm;
1093         acpi_rtc_info.rtc_mon_alarm = acpi_gbl_FADT.month_alarm;
1094         acpi_rtc_info.rtc_century = acpi_gbl_FADT.century;
1095
1096         /* NOTE:  S4_RTC_WAKE is NOT currently useful to Linux */
1097         if (acpi_gbl_FADT.flags & ACPI_FADT_S4_RTC_WAKE)
1098                 dev_info(dev, "RTC can wake from S4\n");
1099
1100         dev->platform_data = &acpi_rtc_info;
1101
1102         /* RTC always wakes from S1/S2/S3, and often S4/STD */
1103         device_init_wakeup(dev, 1);
1104 }
1105
1106 #else
1107
1108 static void cmos_wake_setup(struct device *dev)
1109 {
1110 }
1111
1112 #endif
1113
1114 #ifdef  CONFIG_PNP
1115
1116 #include <linux/pnp.h>
1117
1118 static int cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
1119 {
1120         cmos_wake_setup(&pnp->dev);
1121
1122         if (pnp_port_start(pnp, 0) == 0x70 && !pnp_irq_valid(pnp, 0))
1123                 /* Some machines contain a PNP entry for the RTC, but
1124                  * don't define the IRQ. It should always be safe to
1125                  * hardcode it in these cases
1126                  */
1127                 return cmos_do_probe(&pnp->dev,
1128                                 pnp_get_resource(pnp, IORESOURCE_IO, 0), 8);
1129         else
1130                 return cmos_do_probe(&pnp->dev,
1131                                 pnp_get_resource(pnp, IORESOURCE_IO, 0),
1132                                 pnp_irq(pnp, 0));
1133 }
1134
1135 static void __exit cmos_pnp_remove(struct pnp_dev *pnp)
1136 {
1137         cmos_do_remove(&pnp->dev);
1138 }
1139
1140 static void cmos_pnp_shutdown(struct pnp_dev *pnp)
1141 {
1142         struct device *dev = &pnp->dev;
1143         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1144
1145         if (system_state == SYSTEM_POWER_OFF) {
1146                 int retval = cmos_poweroff(dev);
1147
1148                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1149                         return;
1150         }
1151
1152         cmos_do_shutdown(cmos->irq);
1153 }
1154
1155 static const struct pnp_device_id rtc_ids[] = {
1156         { .id = "PNP0b00", },
1157         { .id = "PNP0b01", },
1158         { .id = "PNP0b02", },
1159         { },
1160 };
1161 MODULE_DEVICE_TABLE(pnp, rtc_ids);
1162
1163 static struct pnp_driver cmos_pnp_driver = {
1164         .name           = (char *) driver_name,
1165         .id_table       = rtc_ids,
1166         .probe          = cmos_pnp_probe,
1167         .remove         = __exit_p(cmos_pnp_remove),
1168         .shutdown       = cmos_pnp_shutdown,
1169
1170         /* flag ensures resume() gets called, and stops syslog spam */
1171         .flags          = PNP_DRIVER_RES_DO_NOT_CHANGE,
1172         .driver         = {
1173                         .pm = &cmos_pm_ops,
1174         },
1175 };
1176
1177 #endif  /* CONFIG_PNP */
1178
1179 #ifdef CONFIG_OF
1180 static const struct of_device_id of_cmos_match[] = {
1181         {
1182                 .compatible = "motorola,mc146818",
1183         },
1184         { },
1185 };
1186 MODULE_DEVICE_TABLE(of, of_cmos_match);
1187
1188 static __init void cmos_of_init(struct platform_device *pdev)
1189 {
1190         struct device_node *node = pdev->dev.of_node;
1191         struct rtc_time time;
1192         int ret;
1193         const __be32 *val;
1194
1195         if (!node)
1196                 return;
1197
1198         val = of_get_property(node, "ctrl-reg", NULL);
1199         if (val)
1200                 CMOS_WRITE(be32_to_cpup(val), RTC_CONTROL);
1201
1202         val = of_get_property(node, "freq-reg", NULL);
1203         if (val)
1204                 CMOS_WRITE(be32_to_cpup(val), RTC_FREQ_SELECT);
1205
1206         get_rtc_time(&time);
1207         ret = rtc_valid_tm(&time);
1208         if (ret) {
1209                 struct rtc_time def_time = {
1210                         .tm_year = 1,
1211                         .tm_mday = 1,
1212                 };
1213                 set_rtc_time(&def_time);
1214         }
1215 }
1216 #else
1217 static inline void cmos_of_init(struct platform_device *pdev) {}
1218 #endif
1219 /*----------------------------------------------------------------*/
1220
1221 /* Platform setup should have set up an RTC device, when PNP is
1222  * unavailable ... this could happen even on (older) PCs.
1223  */
1224
1225 static int __init cmos_platform_probe(struct platform_device *pdev)
1226 {
1227         struct resource *resource;
1228         int irq;
1229
1230         cmos_of_init(pdev);
1231         cmos_wake_setup(&pdev->dev);
1232
1233         if (RTC_IOMAPPED)
1234                 resource = platform_get_resource(pdev, IORESOURCE_IO, 0);
1235         else
1236                 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1237         irq = platform_get_irq(pdev, 0);
1238         if (irq < 0)
1239                 irq = -1;
1240
1241         return cmos_do_probe(&pdev->dev, resource, irq);
1242 }
1243
1244 static int __exit cmos_platform_remove(struct platform_device *pdev)
1245 {
1246         cmos_do_remove(&pdev->dev);
1247         return 0;
1248 }
1249
1250 static void cmos_platform_shutdown(struct platform_device *pdev)
1251 {
1252         struct device *dev = &pdev->dev;
1253         struct cmos_rtc *cmos = dev_get_drvdata(dev);
1254
1255         if (system_state == SYSTEM_POWER_OFF) {
1256                 int retval = cmos_poweroff(dev);
1257
1258                 if (cmos_aie_poweroff(dev) < 0 && !retval)
1259                         return;
1260         }
1261
1262         cmos_do_shutdown(cmos->irq);
1263 }
1264
1265 /* work with hotplug and coldplug */
1266 MODULE_ALIAS("platform:rtc_cmos");
1267
1268 static struct platform_driver cmos_platform_driver = {
1269         .remove         = __exit_p(cmos_platform_remove),
1270         .shutdown       = cmos_platform_shutdown,
1271         .driver = {
1272                 .name           = driver_name,
1273 #ifdef CONFIG_PM
1274                 .pm             = &cmos_pm_ops,
1275 #endif
1276                 .of_match_table = of_match_ptr(of_cmos_match),
1277         }
1278 };
1279
1280 #ifdef CONFIG_PNP
1281 static bool pnp_driver_registered;
1282 #endif
1283 static bool platform_driver_registered;
1284
1285 static int __init cmos_init(void)
1286 {
1287         int retval = 0;
1288
1289 #ifdef  CONFIG_PNP
1290         retval = pnp_register_driver(&cmos_pnp_driver);
1291         if (retval == 0)
1292                 pnp_driver_registered = true;
1293 #endif
1294
1295         if (!cmos_rtc.dev) {
1296                 retval = platform_driver_probe(&cmos_platform_driver,
1297                                                cmos_platform_probe);
1298                 if (retval == 0)
1299                         platform_driver_registered = true;
1300         }
1301
1302         dmi_check_system(rtc_quirks);
1303
1304         if (retval == 0)
1305                 return 0;
1306
1307 #ifdef  CONFIG_PNP
1308         if (pnp_driver_registered)
1309                 pnp_unregister_driver(&cmos_pnp_driver);
1310 #endif
1311         return retval;
1312 }
1313 module_init(cmos_init);
1314
1315 static void __exit cmos_exit(void)
1316 {
1317 #ifdef  CONFIG_PNP
1318         if (pnp_driver_registered)
1319                 pnp_unregister_driver(&cmos_pnp_driver);
1320 #endif
1321         if (platform_driver_registered)
1322                 platform_driver_unregister(&cmos_platform_driver);
1323 }
1324 module_exit(cmos_exit);
1325
1326
1327 MODULE_AUTHOR("David Brownell");
1328 MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
1329 MODULE_LICENSE("GPL");