drivers/rtc/rtc-at91rm9200.c

   1 /*
   2  *      Real Time Clock interface for Linux on Atmel AT91RM9200
   3  *
   4  *      Copyright (C) 2002 Rick Bronson
   5  *
   6  *      Converted to RTC class model by Andrew Victor
   7  *
   8  *      Ported to Linux 2.6 by Steven Scholz
   9  *      Based on s3c2410-rtc.c Simtec Electronics
  10  *
  11  *      Based on sa1100-rtc.c by Nils Faerber
  12  *      Based on rtc.c by Paul Gortmaker
  13  *
  14  *      This program is free software; you can redistribute it and/or
  15  *      modify it under the terms of the GNU General Public License
  16  *      as published by the Free Software Foundation; either version
  17  *      2 of the License, or (at your option) any later version.
  18  *
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/kernel.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/time.h>
  25 #include <linux/rtc.h>
  26 #include <linux/bcd.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/ioctl.h>
  30 #include <linux/completion.h>
  31 #include <linux/io.h>
  32 #include <linux/of.h>
  33 #include <linux/of_device.h>
  34 #include <linux/suspend.h>
  35 #include <linux/uaccess.h>
  36
  37 #include "rtc-at91rm9200.h"
  38
  39 #define at91_rtc_read(field) \
  40         readl_relaxed(at91_rtc_regs + field)
  41 #define at91_rtc_write(field, val) \
  42         writel_relaxed((val), at91_rtc_regs + field)
  43
  44 #define AT91_RTC_EPOCH          1900UL  /* just like arch/arm/common/rtctime.c */
  45
  46 struct at91_rtc_config {
  47         bool use_shadow_imr;
  48 };
  49
  50 static const struct at91_rtc_config *at91_rtc_config;
  51 static DECLARE_COMPLETION(at91_rtc_updated);
  52 static DECLARE_COMPLETION(at91_rtc_upd_rdy);
  53 static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
  54 static void __iomem *at91_rtc_regs;
  55 static int irq;
  56 static DEFINE_SPINLOCK(at91_rtc_lock);
  57 static u32 at91_rtc_shadow_imr;
  58 static bool suspended;
  59 static DEFINE_SPINLOCK(suspended_lock);
  60 static unsigned long cached_events;
  61 static u32 at91_rtc_imr;
  62
  63 static void at91_rtc_write_ier(u32 mask)
  64 {
  65         unsigned long flags;
  66
  67         spin_lock_irqsave(&at91_rtc_lock, flags);
  68         at91_rtc_shadow_imr |= mask;
  69         at91_rtc_write(AT91_RTC_IER, mask);
  70         spin_unlock_irqrestore(&at91_rtc_lock, flags);
  71 }
  72
  73 static void at91_rtc_write_idr(u32 mask)
  74 {
  75         unsigned long flags;
  76
  77         spin_lock_irqsave(&at91_rtc_lock, flags);
  78         at91_rtc_write(AT91_RTC_IDR, mask);
  79         /*
  80          * Register read back (of any RTC-register) needed to make sure
  81          * IDR-register write has reached the peripheral before updating
  82          * shadow mask.
  83          *
  84          * Note that there is still a possibility that the mask is updated
  85          * before interrupts have actually been disabled in hardware. The only
  86          * way to be certain would be to poll the IMR-register, which is is
  87          * the very register we are trying to emulate. The register read back
  88          * is a reasonable heuristic.
  89          */
  90         at91_rtc_read(AT91_RTC_SR);
  91         at91_rtc_shadow_imr &= ~mask;
  92         spin_unlock_irqrestore(&at91_rtc_lock, flags);
  93 }
  94
  95 static u32 at91_rtc_read_imr(void)
  96 {
  97         unsigned long flags;
  98         u32 mask;
  99
 100         if (at91_rtc_config->use_shadow_imr) {
 101                 spin_lock_irqsave(&at91_rtc_lock, flags);
 102                 mask = at91_rtc_shadow_imr;
 103                 spin_unlock_irqrestore(&at91_rtc_lock, flags);
 104         } else {
 105                 mask = at91_rtc_read(AT91_RTC_IMR);
 106         }
 107
 108         return mask;
 109 }
 110
 111 /*
 112  * Decode time/date into rtc_time structure
 113  */
 114 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
 115                                 struct rtc_time *tm)
 116 {
 117         unsigned int time, date;
 118
 119         /* must read twice in case it changes */
 120         do {
 121                 time = at91_rtc_read(timereg);
 122                 date = at91_rtc_read(calreg);
 123         } while ((time != at91_rtc_read(timereg)) ||
 124                         (date != at91_rtc_read(calreg)));
 125
 126         tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
 127         tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
 128         tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
 129
 130         /*
 131          * The Calendar Alarm register does not have a field for
 132          * the year - so these will return an invalid value.  When an
 133          * alarm is set, at91_alarm_year will store the current year.
 134          */
 135         tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;     /* century */
 136         tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);    /* year */
 137
 138         tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
 139         tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
 140         tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
 141 }
 142
 143 /*
 144  * Read current time and date in RTC
 145  */
 146 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
 147 {
 148         at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
 149         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 150         tm->tm_year = tm->tm_year - 1900;
 151
 152         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 153                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 154                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 155
 156         return 0;
 157 }
 158
 159 /*
 160  * Set current time and date in RTC
 161  */
 162 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
 163 {
 164         unsigned long cr;
 165
 166         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 167                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 168                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 169
 170         wait_for_completion(&at91_rtc_upd_rdy);
 171
 172         /* Stop Time/Calendar from counting */
 173         cr = at91_rtc_read(AT91_RTC_CR);
 174         at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
 175
 176         at91_rtc_write_ier(AT91_RTC_ACKUPD);
 177         wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
 178         at91_rtc_write_idr(AT91_RTC_ACKUPD);
 179
 180         at91_rtc_write(AT91_RTC_TIMR,
 181                           bin2bcd(tm->tm_sec) << 0
 182                         | bin2bcd(tm->tm_min) << 8
 183                         | bin2bcd(tm->tm_hour) << 16);
 184
 185         at91_rtc_write(AT91_RTC_CALR,
 186                           bin2bcd((tm->tm_year + 1900) / 100)   /* century */
 187                         | bin2bcd(tm->tm_year % 100) << 8       /* year */
 188                         | bin2bcd(tm->tm_mon + 1) << 16         /* tm_mon starts at zero */
 189                         | bin2bcd(tm->tm_wday + 1) << 21        /* day of the week [0-6], Sunday=0 */
 190                         | bin2bcd(tm->tm_mday) << 24);
 191
 192         /* Restart Time/Calendar */
 193         cr = at91_rtc_read(AT91_RTC_CR);
 194         at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
 195         at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
 196         at91_rtc_write_ier(AT91_RTC_SECEV);
 197
 198         return 0;
 199 }
 200
 201 /*
 202  * Read alarm time and date in RTC
 203  */
 204 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 205 {
 206         struct rtc_time *tm = &alrm->time;
 207
 208         at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
 209         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 210         tm->tm_year = at91_alarm_year - 1900;
 211
 212         alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
 213                         ? 1 : 0;
 214
 215         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 216                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 217                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 218
 219         return 0;
 220 }
 221
 222 /*
 223  * Set alarm time and date in RTC
 224  */
 225 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 226 {
 227         struct rtc_time tm;
 228
 229         at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
 230
 231         at91_alarm_year = tm.tm_year;
 232
 233         tm.tm_mon = alrm->time.tm_mon;
 234         tm.tm_mday = alrm->time.tm_mday;
 235         tm.tm_hour = alrm->time.tm_hour;
 236         tm.tm_min = alrm->time.tm_min;
 237         tm.tm_sec = alrm->time.tm_sec;
 238
 239         at91_rtc_write_idr(AT91_RTC_ALARM);
 240         at91_rtc_write(AT91_RTC_TIMALR,
 241                   bin2bcd(tm.tm_sec) << 0
 242                 | bin2bcd(tm.tm_min) << 8
 243                 | bin2bcd(tm.tm_hour) << 16
 244                 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
 245         at91_rtc_write(AT91_RTC_CALALR,
 246                   bin2bcd(tm.tm_mon + 1) << 16          /* tm_mon starts at zero */
 247                 | bin2bcd(tm.tm_mday) << 24
 248                 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
 249
 250         if (alrm->enabled) {
 251                 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 252                 at91_rtc_write_ier(AT91_RTC_ALARM);
 253         }
 254
 255         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 256                 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
 257                 tm.tm_min, tm.tm_sec);
 258
 259         return 0;
 260 }
 261
 262 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 263 {
 264         dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
 265
 266         if (enabled) {
 267                 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 268                 at91_rtc_write_ier(AT91_RTC_ALARM);
 269         } else
 270                 at91_rtc_write_idr(AT91_RTC_ALARM);
 271
 272         return 0;
 273 }
 274 /*
 275  * Provide additional RTC information in /proc/driver/rtc
 276  */
 277 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
 278 {
 279         unsigned long imr = at91_rtc_read_imr();
 280
 281         seq_printf(seq, "update_IRQ\t: %s\n",
 282                         (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
 283         seq_printf(seq, "periodic_IRQ\t: %s\n",
 284                         (imr & AT91_RTC_SECEV) ? "yes" : "no");
 285
 286         return 0;
 287 }
 288
 289 /*
 290  * IRQ handler for the RTC
 291  */
 292 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
 293 {
 294         struct platform_device *pdev = dev_id;
 295         struct rtc_device *rtc = platform_get_drvdata(pdev);
 296         unsigned int rtsr;
 297         unsigned long events = 0;
 298         int ret = IRQ_NONE;
 299
 300         spin_lock(&suspended_lock);
 301         rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
 302         if (rtsr) {             /* this interrupt is shared!  Is it ours? */
 303                 if (rtsr & AT91_RTC_ALARM)
 304                         events |= (RTC_AF | RTC_IRQF);
 305                 if (rtsr & AT91_RTC_SECEV) {
 306                         complete(&at91_rtc_upd_rdy);
 307                         at91_rtc_write_idr(AT91_RTC_SECEV);
 308                 }
 309                 if (rtsr & AT91_RTC_ACKUPD)
 310                         complete(&at91_rtc_updated);
 311
 312                 at91_rtc_write(AT91_RTC_SCCR, rtsr);    /* clear status reg */
 313
 314                 if (!suspended) {
 315                         rtc_update_irq(rtc, 1, events);
 316
 317                         dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n",
 318                                 __func__, events >> 8, events & 0x000000FF);
 319                 } else {
 320                         cached_events |= events;
 321                         at91_rtc_write_idr(at91_rtc_imr);
 322                         pm_system_wakeup();
 323                 }
 324
 325                 ret = IRQ_HANDLED;
 326         }
 327         spin_unlock(&suspended_lock);
 328
 329         return ret;
 330 }
 331
 332 static const struct at91_rtc_config at91rm9200_config = {
 333 };
 334
 335 static const struct at91_rtc_config at91sam9x5_config = {
 336         .use_shadow_imr = true,
 337 };
 338
 339 #ifdef CONFIG_OF
 340 static const struct of_device_id at91_rtc_dt_ids[] = {
 341         {
 342                 .compatible = "atmel,at91rm9200-rtc",
 343                 .data = &at91rm9200_config,
 344         }, {
 345                 .compatible = "atmel,at91sam9x5-rtc",
 346                 .data = &at91sam9x5_config,
 347         }, {
 348                 /* sentinel */
 349         }
 350 };
 351 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
 352 #endif
 353
 354 static const struct at91_rtc_config *
 355 at91_rtc_get_config(struct platform_device *pdev)
 356 {
 357         const struct of_device_id *match;
 358
 359         if (pdev->dev.of_node) {
 360                 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
 361                 if (!match)
 362                         return NULL;
 363                 return (const struct at91_rtc_config *)match->data;
 364         }
 365
 366         return &at91rm9200_config;
 367 }
 368
 369 static const struct rtc_class_ops at91_rtc_ops = {
 370         .read_time      = at91_rtc_readtime,
 371         .set_time       = at91_rtc_settime,
 372         .read_alarm     = at91_rtc_readalarm,
 373         .set_alarm      = at91_rtc_setalarm,
 374         .proc           = at91_rtc_proc,
 375         .alarm_irq_enable = at91_rtc_alarm_irq_enable,
 376 };
 377
 378 /*
 379  * Initialize and install RTC driver
 380  */
 381 static int __init at91_rtc_probe(struct platform_device *pdev)
 382 {
 383         struct rtc_device *rtc;
 384         struct resource *regs;
 385         int ret = 0;
 386
 387         at91_rtc_config = at91_rtc_get_config(pdev);
 388         if (!at91_rtc_config)
 389                 return -ENODEV;
 390
 391         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 392         if (!regs) {
 393                 dev_err(&pdev->dev, "no mmio resource defined\n");
 394                 return -ENXIO;
 395         }
 396
 397         irq = platform_get_irq(pdev, 0);
 398         if (irq < 0) {
 399                 dev_err(&pdev->dev, "no irq resource defined\n");
 400                 return -ENXIO;
 401         }
 402
 403         at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start,
 404                                      resource_size(regs));
 405         if (!at91_rtc_regs) {
 406                 dev_err(&pdev->dev, "failed to map registers, aborting.\n");
 407                 return -ENOMEM;
 408         }
 409
 410         at91_rtc_write(AT91_RTC_CR, 0);
 411         at91_rtc_write(AT91_RTC_MR, 0);         /* 24 hour mode */
 412
 413         /* Disable all interrupts */
 414         at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 415                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 416                                         AT91_RTC_CALEV);
 417
 418         ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt,
 419                                IRQF_SHARED | IRQF_COND_SUSPEND,
 420                                "at91_rtc", pdev);
 421         if (ret) {
 422                 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
 423                 return ret;
 424         }
 425
 426         /* cpu init code should really have flagged this device as
 427          * being wake-capable; if it didn't, do that here.
 428          */
 429         if (!device_can_wakeup(&pdev->dev))
 430                 device_init_wakeup(&pdev->dev, 1);
 431
 432         rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 433                                 &at91_rtc_ops, THIS_MODULE);
 434         if (IS_ERR(rtc))
 435                 return PTR_ERR(rtc);
 436         platform_set_drvdata(pdev, rtc);
 437
 438         /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
 439          * completion.
 440          */
 441         at91_rtc_write_ier(AT91_RTC_SECEV);
 442
 443         dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
 444         return 0;
 445 }
 446
 447 /*
 448  * Disable and remove the RTC driver
 449  */
 450 static int __exit at91_rtc_remove(struct platform_device *pdev)
 451 {
 452         /* Disable all interrupts */
 453         at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 454                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 455                                         AT91_RTC_CALEV);
 456
 457         return 0;
 458 }
 459
 460 static void at91_rtc_shutdown(struct platform_device *pdev)
 461 {
 462         /* Disable all interrupts */
 463         at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 464                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 465                                         AT91_RTC_CALEV);
 466 }
 467
 468 #ifdef CONFIG_PM_SLEEP
 469
 470 /* AT91RM9200 RTC Power management control */
 471
 472 static int at91_rtc_suspend(struct device *dev)
 473 {
 474         /* this IRQ is shared with DBGU and other hardware which isn't
 475          * necessarily doing PM like we are...
 476          */
 477         at91_rtc_imr = at91_rtc_read_imr()
 478                         & (AT91_RTC_ALARM|AT91_RTC_SECEV);
 479         if (at91_rtc_imr) {
 480                 if (device_may_wakeup(dev)) {
 481                         unsigned long flags;
 482
 483                         enable_irq_wake(irq);
 484
 485                         spin_lock_irqsave(&suspended_lock, flags);
 486                         suspended = true;
 487                         spin_unlock_irqrestore(&suspended_lock, flags);
 488                 } else {
 489                         at91_rtc_write_idr(at91_rtc_imr);
 490                 }
 491         }
 492         return 0;
 493 }
 494
 495 static int at91_rtc_resume(struct device *dev)
 496 {
 497         struct rtc_device *rtc = dev_get_drvdata(dev);
 498
 499         if (at91_rtc_imr) {
 500                 if (device_may_wakeup(dev)) {
 501                         unsigned long flags;
 502
 503                         spin_lock_irqsave(&suspended_lock, flags);
 504
 505                         if (cached_events) {
 506                                 rtc_update_irq(rtc, 1, cached_events);
 507                                 cached_events = 0;
 508                         }
 509
 510                         suspended = false;
 511                         spin_unlock_irqrestore(&suspended_lock, flags);
 512
 513                         disable_irq_wake(irq);
 514                 }
 515                 at91_rtc_write_ier(at91_rtc_imr);
 516         }
 517         return 0;
 518 }
 519 #endif
 520
 521 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
 522
 523 static struct platform_driver at91_rtc_driver = {
 524         .remove         = __exit_p(at91_rtc_remove),
 525         .shutdown       = at91_rtc_shutdown,
 526         .driver         = {
 527                 .name   = "at91_rtc",
 528                 .pm     = &at91_rtc_pm_ops,
 529                 .of_match_table = of_match_ptr(at91_rtc_dt_ids),
 530         },
 531 };
 532
 533 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
 534
 535 MODULE_AUTHOR("Rick Bronson");
 536 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
 537 MODULE_LICENSE("GPL");
 538 MODULE_ALIAS("platform:at91_rtc");