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/bcd.h>
  22 #include <linux/clk.h>
  23 #include <linux/completion.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/ioctl.h>
  26 #include <linux/io.h>
  27 #include <linux/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/of_device.h>
  30 #include <linux/of.h>
  31 #include <linux/platform_device.h>
  32 #include <linux/rtc.h>
  33 #include <linux/spinlock.h>
  34 #include <linux/suspend.h>
  35 #include <linux/time.h>
  36 #include <linux/uaccess.h>
  37
  38 #include "rtc-at91rm9200.h"
  39
  40 #define at91_rtc_read(field) \
  41         readl_relaxed(at91_rtc_regs + field)
  42 #define at91_rtc_write(field, val) \
  43         writel_relaxed((val), at91_rtc_regs + field)
  44
  45 #define AT91_RTC_EPOCH          1900UL  /* just like arch/arm/common/rtctime.c */
  46
  47 struct at91_rtc_config {
  48         bool use_shadow_imr;
  49 };
  50
  51 static const struct at91_rtc_config *at91_rtc_config;
  52 static DECLARE_COMPLETION(at91_rtc_updated);
  53 static DECLARE_COMPLETION(at91_rtc_upd_rdy);
  54 static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
  55 static void __iomem *at91_rtc_regs;
  56 static int irq;
  57 static DEFINE_SPINLOCK(at91_rtc_lock);
  58 static u32 at91_rtc_shadow_imr;
  59 static bool suspended;
  60 static DEFINE_SPINLOCK(suspended_lock);
  61 static unsigned long cached_events;
  62 static u32 at91_rtc_imr;
  63 static struct clk *sclk;
  64
  65 static void at91_rtc_write_ier(u32 mask)
  66 {
  67         unsigned long flags;
  68
  69         spin_lock_irqsave(&at91_rtc_lock, flags);
  70         at91_rtc_shadow_imr |= mask;
  71         at91_rtc_write(AT91_RTC_IER, mask);
  72         spin_unlock_irqrestore(&at91_rtc_lock, flags);
  73 }
  74
  75 static void at91_rtc_write_idr(u32 mask)
  76 {
  77         unsigned long flags;
  78
  79         spin_lock_irqsave(&at91_rtc_lock, flags);
  80         at91_rtc_write(AT91_RTC_IDR, mask);
  81         /*
  82          * Register read back (of any RTC-register) needed to make sure
  83          * IDR-register write has reached the peripheral before updating
  84          * shadow mask.
  85          *
  86          * Note that there is still a possibility that the mask is updated
  87          * before interrupts have actually been disabled in hardware. The only
  88          * way to be certain would be to poll the IMR-register, which is is
  89          * the very register we are trying to emulate. The register read back
  90          * is a reasonable heuristic.
  91          */
  92         at91_rtc_read(AT91_RTC_SR);
  93         at91_rtc_shadow_imr &= ~mask;
  94         spin_unlock_irqrestore(&at91_rtc_lock, flags);
  95 }
  96
  97 static u32 at91_rtc_read_imr(void)
  98 {
  99         unsigned long flags;
 100         u32 mask;
 101
 102         if (at91_rtc_config->use_shadow_imr) {
 103                 spin_lock_irqsave(&at91_rtc_lock, flags);
 104                 mask = at91_rtc_shadow_imr;
 105                 spin_unlock_irqrestore(&at91_rtc_lock, flags);
 106         } else {
 107                 mask = at91_rtc_read(AT91_RTC_IMR);
 108         }
 109
 110         return mask;
 111 }
 112
 113 /*
 114  * Decode time/date into rtc_time structure
 115  */
 116 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
 117                                 struct rtc_time *tm)
 118 {
 119         unsigned int time, date;
 120
 121         /* must read twice in case it changes */
 122         do {
 123                 time = at91_rtc_read(timereg);
 124                 date = at91_rtc_read(calreg);
 125         } while ((time != at91_rtc_read(timereg)) ||
 126                         (date != at91_rtc_read(calreg)));
 127
 128         tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
 129         tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
 130         tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
 131
 132         /*
 133          * The Calendar Alarm register does not have a field for
 134          * the year - so these will return an invalid value.  When an
 135          * alarm is set, at91_alarm_year will store the current year.
 136          */
 137         tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;     /* century */
 138         tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);    /* year */
 139
 140         tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
 141         tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
 142         tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
 143 }
 144
 145 /*
 146  * Read current time and date in RTC
 147  */
 148 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
 149 {
 150         at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
 151         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 152         tm->tm_year = tm->tm_year - 1900;
 153
 154         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 155                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 156                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 157
 158         return 0;
 159 }
 160
 161 /*
 162  * Set current time and date in RTC
 163  */
 164 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
 165 {
 166         unsigned long cr;
 167
 168         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 169                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 170                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 171
 172         wait_for_completion(&at91_rtc_upd_rdy);
 173
 174         /* Stop Time/Calendar from counting */
 175         cr = at91_rtc_read(AT91_RTC_CR);
 176         at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
 177
 178         at91_rtc_write_ier(AT91_RTC_ACKUPD);
 179         wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
 180         at91_rtc_write_idr(AT91_RTC_ACKUPD);
 181
 182         at91_rtc_write(AT91_RTC_TIMR,
 183                           bin2bcd(tm->tm_sec) << 0
 184                         | bin2bcd(tm->tm_min) << 8
 185                         | bin2bcd(tm->tm_hour) << 16);
 186
 187         at91_rtc_write(AT91_RTC_CALR,
 188                           bin2bcd((tm->tm_year + 1900) / 100)   /* century */
 189                         | bin2bcd(tm->tm_year % 100) << 8       /* year */
 190                         | bin2bcd(tm->tm_mon + 1) << 16         /* tm_mon starts at zero */
 191                         | bin2bcd(tm->tm_wday + 1) << 21        /* day of the week [0-6], Sunday=0 */
 192                         | bin2bcd(tm->tm_mday) << 24);
 193
 194         /* Restart Time/Calendar */
 195         cr = at91_rtc_read(AT91_RTC_CR);
 196         at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
 197         at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
 198         at91_rtc_write_ier(AT91_RTC_SECEV);
 199
 200         return 0;
 201 }
 202
 203 /*
 204  * Read alarm time and date in RTC
 205  */
 206 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 207 {
 208         struct rtc_time *tm = &alrm->time;
 209
 210         at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
 211         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 212         tm->tm_year = at91_alarm_year - 1900;
 213
 214         alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
 215                         ? 1 : 0;
 216
 217         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 218                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 219                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 220
 221         return 0;
 222 }
 223
 224 /*
 225  * Set alarm time and date in RTC
 226  */
 227 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 228 {
 229         struct rtc_time tm;
 230
 231         at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
 232
 233         at91_alarm_year = tm.tm_year;
 234
 235         tm.tm_mon = alrm->time.tm_mon;
 236         tm.tm_mday = alrm->time.tm_mday;
 237         tm.tm_hour = alrm->time.tm_hour;
 238         tm.tm_min = alrm->time.tm_min;
 239         tm.tm_sec = alrm->time.tm_sec;
 240
 241         at91_rtc_write_idr(AT91_RTC_ALARM);
 242         at91_rtc_write(AT91_RTC_TIMALR,
 243                   bin2bcd(tm.tm_sec) << 0
 244                 | bin2bcd(tm.tm_min) << 8
 245                 | bin2bcd(tm.tm_hour) << 16
 246                 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
 247         at91_rtc_write(AT91_RTC_CALALR,
 248                   bin2bcd(tm.tm_mon + 1) << 16          /* tm_mon starts at zero */
 249                 | bin2bcd(tm.tm_mday) << 24
 250                 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
 251
 252         if (alrm->enabled) {
 253                 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 254                 at91_rtc_write_ier(AT91_RTC_ALARM);
 255         }
 256
 257         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 258                 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
 259                 tm.tm_min, tm.tm_sec);
 260
 261         return 0;
 262 }
 263
 264 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 265 {
 266         dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
 267
 268         if (enabled) {
 269                 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 270                 at91_rtc_write_ier(AT91_RTC_ALARM);
 271         } else
 272                 at91_rtc_write_idr(AT91_RTC_ALARM);
 273
 274         return 0;
 275 }
 276 /*
 277  * Provide additional RTC information in /proc/driver/rtc
 278  */
 279 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
 280 {
 281         unsigned long imr = at91_rtc_read_imr();
 282
 283         seq_printf(seq, "update_IRQ\t: %s\n",
 284                         (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
 285         seq_printf(seq, "periodic_IRQ\t: %s\n",
 286                         (imr & AT91_RTC_SECEV) ? "yes" : "no");
 287
 288         return 0;
 289 }
 290
 291 /*
 292  * IRQ handler for the RTC
 293  */
 294 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
 295 {
 296         struct platform_device *pdev = dev_id;
 297         struct rtc_device *rtc = platform_get_drvdata(pdev);
 298         unsigned int rtsr;
 299         unsigned long events = 0;
 300         int ret = IRQ_NONE;
 301
 302         spin_lock(&suspended_lock);
 303         rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
 304         if (rtsr) {             /* this interrupt is shared!  Is it ours? */
 305                 if (rtsr & AT91_RTC_ALARM)
 306                         events |= (RTC_AF | RTC_IRQF);
 307                 if (rtsr & AT91_RTC_SECEV) {
 308                         complete(&at91_rtc_upd_rdy);
 309                         at91_rtc_write_idr(AT91_RTC_SECEV);
 310                 }
 311                 if (rtsr & AT91_RTC_ACKUPD)
 312                         complete(&at91_rtc_updated);
 313
 314                 at91_rtc_write(AT91_RTC_SCCR, rtsr);    /* clear status reg */
 315
 316                 if (!suspended) {
 317                         rtc_update_irq(rtc, 1, events);
 318
 319                         dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n",
 320                                 __func__, events >> 8, events & 0x000000FF);
 321                 } else {
 322                         cached_events |= events;
 323                         at91_rtc_write_idr(at91_rtc_imr);
 324                         pm_system_wakeup();
 325                 }
 326
 327                 ret = IRQ_HANDLED;
 328         }
 329         spin_unlock(&suspended_lock);
 330
 331         return ret;
 332 }
 333
 334 static const struct at91_rtc_config at91rm9200_config = {
 335 };
 336
 337 static const struct at91_rtc_config at91sam9x5_config = {
 338         .use_shadow_imr = true,
 339 };
 340
 341 #ifdef CONFIG_OF
 342 static const struct of_device_id at91_rtc_dt_ids[] = {
 343         {
 344                 .compatible = "atmel,at91rm9200-rtc",
 345                 .data = &at91rm9200_config,
 346         }, {
 347                 .compatible = "atmel,at91sam9x5-rtc",
 348                 .data = &at91sam9x5_config,
 349         }, {
 350                 /* sentinel */
 351         }
 352 };
 353 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
 354 #endif
 355
 356 static const struct at91_rtc_config *
 357 at91_rtc_get_config(struct platform_device *pdev)
 358 {
 359         const struct of_device_id *match;
 360
 361         if (pdev->dev.of_node) {
 362                 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
 363                 if (!match)
 364                         return NULL;
 365                 return (const struct at91_rtc_config *)match->data;
 366         }
 367
 368         return &at91rm9200_config;
 369 }
 370
 371 static const struct rtc_class_ops at91_rtc_ops = {
 372         .read_time      = at91_rtc_readtime,
 373         .set_time       = at91_rtc_settime,
 374         .read_alarm     = at91_rtc_readalarm,
 375         .set_alarm      = at91_rtc_setalarm,
 376         .proc           = at91_rtc_proc,
 377         .alarm_irq_enable = at91_rtc_alarm_irq_enable,
 378 };
 379
 380 /*
 381  * Initialize and install RTC driver
 382  */
 383 static int __init at91_rtc_probe(struct platform_device *pdev)
 384 {
 385         struct rtc_device *rtc;
 386         struct resource *regs;
 387         int ret = 0;
 388
 389         at91_rtc_config = at91_rtc_get_config(pdev);
 390         if (!at91_rtc_config)
 391                 return -ENODEV;
 392
 393         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 394         if (!regs) {
 395                 dev_err(&pdev->dev, "no mmio resource defined\n");
 396                 return -ENXIO;
 397         }
 398
 399         irq = platform_get_irq(pdev, 0);
 400         if (irq < 0) {
 401                 dev_err(&pdev->dev, "no irq resource defined\n");
 402                 return -ENXIO;
 403         }
 404
 405         at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start,
 406                                      resource_size(regs));
 407         if (!at91_rtc_regs) {
 408                 dev_err(&pdev->dev, "failed to map registers, aborting.\n");
 409                 return -ENOMEM;
 410         }
 411
 412         sclk = devm_clk_get(&pdev->dev, NULL);
 413         if (IS_ERR(sclk))
 414                 return PTR_ERR(sclk);
 415
 416         ret = clk_prepare_enable(sclk);
 417         if (ret) {
 418                 dev_err(&pdev->dev, "Could not enable slow clock\n");
 419                 return ret;
 420         }
 421
 422         at91_rtc_write(AT91_RTC_CR, 0);
 423         at91_rtc_write(AT91_RTC_MR, 0);         /* 24 hour mode */
 424
 425         /* Disable all interrupts */
 426         at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 427                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 428                                         AT91_RTC_CALEV);
 429
 430         ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt,
 431                                IRQF_SHARED | IRQF_COND_SUSPEND,
 432                                "at91_rtc", pdev);
 433         if (ret) {
 434                 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
 435                 goto err_clk;
 436         }
 437
 438         /* cpu init code should really have flagged this device as
 439          * being wake-capable; if it didn't, do that here.
 440          */
 441         if (!device_can_wakeup(&pdev->dev))
 442                 device_init_wakeup(&pdev->dev, 1);
 443
 444         rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 445                                 &at91_rtc_ops, THIS_MODULE);
 446         if (IS_ERR(rtc)) {
 447                 ret = PTR_ERR(rtc);
 448                 goto err_clk;
 449         }
 450         platform_set_drvdata(pdev, rtc);
 451
 452         /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
 453          * completion.
 454          */
 455         at91_rtc_write_ier(AT91_RTC_SECEV);
 456
 457         dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
 458         return 0;
 459
 460 err_clk:
 461         clk_disable_unprepare(sclk);
 462
 463         return ret;
 464 }
 465
 466 /*
 467  * Disable and remove the RTC driver
 468  */
 469 static int __exit at91_rtc_remove(struct platform_device *pdev)
 470 {
 471         /* Disable all interrupts */
 472         at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 473                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 474                                         AT91_RTC_CALEV);
 475
 476         clk_disable_unprepare(sclk);
 477
 478         return 0;
 479 }
 480
 481 static void at91_rtc_shutdown(struct platform_device *pdev)
 482 {
 483         /* Disable all interrupts */
 484         at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 485                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 486                                         AT91_RTC_CALEV);
 487 }
 488
 489 #ifdef CONFIG_PM_SLEEP
 490
 491 /* AT91RM9200 RTC Power management control */
 492
 493 static int at91_rtc_suspend(struct device *dev)
 494 {
 495         /* this IRQ is shared with DBGU and other hardware which isn't
 496          * necessarily doing PM like we are...
 497          */
 498         at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 499
 500         at91_rtc_imr = at91_rtc_read_imr()
 501                         & (AT91_RTC_ALARM|AT91_RTC_SECEV);
 502         if (at91_rtc_imr) {
 503                 if (device_may_wakeup(dev)) {
 504                         unsigned long flags;
 505
 506                         enable_irq_wake(irq);
 507
 508                         spin_lock_irqsave(&suspended_lock, flags);
 509                         suspended = true;
 510                         spin_unlock_irqrestore(&suspended_lock, flags);
 511                 } else {
 512                         at91_rtc_write_idr(at91_rtc_imr);
 513                 }
 514         }
 515         return 0;
 516 }
 517
 518 static int at91_rtc_resume(struct device *dev)
 519 {
 520         struct rtc_device *rtc = dev_get_drvdata(dev);
 521
 522         if (at91_rtc_imr) {
 523                 if (device_may_wakeup(dev)) {
 524                         unsigned long flags;
 525
 526                         spin_lock_irqsave(&suspended_lock, flags);
 527
 528                         if (cached_events) {
 529                                 rtc_update_irq(rtc, 1, cached_events);
 530                                 cached_events = 0;
 531                         }
 532
 533                         suspended = false;
 534                         spin_unlock_irqrestore(&suspended_lock, flags);
 535
 536                         disable_irq_wake(irq);
 537                 }
 538                 at91_rtc_write_ier(at91_rtc_imr);
 539         }
 540         return 0;
 541 }
 542 #endif
 543
 544 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
 545
 546 static struct platform_driver at91_rtc_driver = {
 547         .remove         = __exit_p(at91_rtc_remove),
 548         .shutdown       = at91_rtc_shutdown,
 549         .driver         = {
 550                 .name   = "at91_rtc",
 551                 .pm     = &at91_rtc_pm_ops,
 552                 .of_match_table = of_match_ptr(at91_rtc_dt_ids),
 553         },
 554 };
 555
 556 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
 557
 558 MODULE_AUTHOR("Rick Bronson");
 559 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
 560 MODULE_LICENSE("GPL");
 561 MODULE_ALIAS("platform:at91_rtc");