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 struct at91_rtc_config {
  46         bool use_shadow_imr;
  47 };
  48
  49 static const struct at91_rtc_config *at91_rtc_config;
  50 static DECLARE_COMPLETION(at91_rtc_updated);
  51 static DECLARE_COMPLETION(at91_rtc_upd_rdy);
  52 static void __iomem *at91_rtc_regs;
  53 static int irq;
  54 static DEFINE_SPINLOCK(at91_rtc_lock);
  55 static u32 at91_rtc_shadow_imr;
  56 static bool suspended;
  57 static DEFINE_SPINLOCK(suspended_lock);
  58 static unsigned long cached_events;
  59 static u32 at91_rtc_imr;
  60 static struct clk *sclk;
  61
  62 static void at91_rtc_write_ier(u32 mask)
  63 {
  64         unsigned long flags;
  65
  66         spin_lock_irqsave(&at91_rtc_lock, flags);
  67         at91_rtc_shadow_imr |= mask;
  68         at91_rtc_write(AT91_RTC_IER, mask);
  69         spin_unlock_irqrestore(&at91_rtc_lock, flags);
  70 }
  71
  72 static void at91_rtc_write_idr(u32 mask)
  73 {
  74         unsigned long flags;
  75
  76         spin_lock_irqsave(&at91_rtc_lock, flags);
  77         at91_rtc_write(AT91_RTC_IDR, mask);
  78         /*
  79          * Register read back (of any RTC-register) needed to make sure
  80          * IDR-register write has reached the peripheral before updating
  81          * shadow mask.
  82          *
  83          * Note that there is still a possibility that the mask is updated
  84          * before interrupts have actually been disabled in hardware. The only
  85          * way to be certain would be to poll the IMR-register, which is is
  86          * the very register we are trying to emulate. The register read back
  87          * is a reasonable heuristic.
  88          */
  89         at91_rtc_read(AT91_RTC_SR);
  90         at91_rtc_shadow_imr &= ~mask;
  91         spin_unlock_irqrestore(&at91_rtc_lock, flags);
  92 }
  93
  94 static u32 at91_rtc_read_imr(void)
  95 {
  96         unsigned long flags;
  97         u32 mask;
  98
  99         if (at91_rtc_config->use_shadow_imr) {
 100                 spin_lock_irqsave(&at91_rtc_lock, flags);
 101                 mask = at91_rtc_shadow_imr;
 102                 spin_unlock_irqrestore(&at91_rtc_lock, flags);
 103         } else {
 104                 mask = at91_rtc_read(AT91_RTC_IMR);
 105         }
 106
 107         return mask;
 108 }
 109
 110 /*
 111  * Decode time/date into rtc_time structure
 112  */
 113 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
 114                                 struct rtc_time *tm)
 115 {
 116         unsigned int time, date;
 117
 118         /* must read twice in case it changes */
 119         do {
 120                 time = at91_rtc_read(timereg);
 121                 date = at91_rtc_read(calreg);
 122         } while ((time != at91_rtc_read(timereg)) ||
 123                         (date != at91_rtc_read(calreg)));
 124
 125         tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
 126         tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
 127         tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
 128
 129         /*
 130          * The Calendar Alarm register does not have a field for
 131          * the year - so these will return an invalid value.
 132          */
 133         tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;     /* century */
 134         tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);    /* year */
 135
 136         tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
 137         tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
 138         tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
 139 }
 140
 141 /*
 142  * Read current time and date in RTC
 143  */
 144 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
 145 {
 146         at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
 147         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 148         tm->tm_year = tm->tm_year - 1900;
 149
 150         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 151                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 152                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 153
 154         return 0;
 155 }
 156
 157 /*
 158  * Set current time and date in RTC
 159  */
 160 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
 161 {
 162         unsigned long cr;
 163
 164         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 165                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 166                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 167
 168         wait_for_completion(&at91_rtc_upd_rdy);
 169
 170         /* Stop Time/Calendar from counting */
 171         cr = at91_rtc_read(AT91_RTC_CR);
 172         at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
 173
 174         at91_rtc_write_ier(AT91_RTC_ACKUPD);
 175         wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
 176         at91_rtc_write_idr(AT91_RTC_ACKUPD);
 177
 178         at91_rtc_write(AT91_RTC_TIMR,
 179                           bin2bcd(tm->tm_sec) << 0
 180                         | bin2bcd(tm->tm_min) << 8
 181                         | bin2bcd(tm->tm_hour) << 16);
 182
 183         at91_rtc_write(AT91_RTC_CALR,
 184                           bin2bcd((tm->tm_year + 1900) / 100)   /* century */
 185                         | bin2bcd(tm->tm_year % 100) << 8       /* year */
 186                         | bin2bcd(tm->tm_mon + 1) << 16         /* tm_mon starts at zero */
 187                         | bin2bcd(tm->tm_wday + 1) << 21        /* day of the week [0-6], Sunday=0 */
 188                         | bin2bcd(tm->tm_mday) << 24);
 189
 190         /* Restart Time/Calendar */
 191         cr = at91_rtc_read(AT91_RTC_CR);
 192         at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
 193         at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
 194         at91_rtc_write_ier(AT91_RTC_SECEV);
 195
 196         return 0;
 197 }
 198
 199 /*
 200  * Read alarm time and date in RTC
 201  */
 202 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 203 {
 204         struct rtc_time *tm = &alrm->time;
 205
 206         at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
 207         tm->tm_year = -1;
 208
 209         alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
 210                         ? 1 : 0;
 211
 212         dev_dbg(dev, "%s(): %02d-%02d %02d:%02d:%02d %sabled\n", __func__,
 213                 tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec,
 214                 alrm->enabled ? "en" : "dis");
 215
 216         return 0;
 217 }
 218
 219 /*
 220  * Set alarm time and date in RTC
 221  */
 222 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 223 {
 224         struct rtc_time tm;
 225
 226         at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
 227
 228         tm.tm_mon = alrm->time.tm_mon;
 229         tm.tm_mday = alrm->time.tm_mday;
 230         tm.tm_hour = alrm->time.tm_hour;
 231         tm.tm_min = alrm->time.tm_min;
 232         tm.tm_sec = alrm->time.tm_sec;
 233
 234         at91_rtc_write_idr(AT91_RTC_ALARM);
 235         at91_rtc_write(AT91_RTC_TIMALR,
 236                   bin2bcd(tm.tm_sec) << 0
 237                 | bin2bcd(tm.tm_min) << 8
 238                 | bin2bcd(tm.tm_hour) << 16
 239                 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
 240         at91_rtc_write(AT91_RTC_CALALR,
 241                   bin2bcd(tm.tm_mon + 1) << 16          /* tm_mon starts at zero */
 242                 | bin2bcd(tm.tm_mday) << 24
 243                 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
 244
 245         if (alrm->enabled) {
 246                 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 247                 at91_rtc_write_ier(AT91_RTC_ALARM);
 248         }
 249
 250         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 251                 tm.tm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
 252                 tm.tm_min, tm.tm_sec);
 253
 254         return 0;
 255 }
 256
 257 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 258 {
 259         dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
 260
 261         if (enabled) {
 262                 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 263                 at91_rtc_write_ier(AT91_RTC_ALARM);
 264         } else
 265                 at91_rtc_write_idr(AT91_RTC_ALARM);
 266
 267         return 0;
 268 }
 269 /*
 270  * Provide additional RTC information in /proc/driver/rtc
 271  */
 272 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
 273 {
 274         unsigned long imr = at91_rtc_read_imr();
 275
 276         seq_printf(seq, "update_IRQ\t: %s\n",
 277                         (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
 278         seq_printf(seq, "periodic_IRQ\t: %s\n",
 279                         (imr & AT91_RTC_SECEV) ? "yes" : "no");
 280
 281         return 0;
 282 }
 283
 284 /*
 285  * IRQ handler for the RTC
 286  */
 287 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
 288 {
 289         struct platform_device *pdev = dev_id;
 290         struct rtc_device *rtc = platform_get_drvdata(pdev);
 291         unsigned int rtsr;
 292         unsigned long events = 0;
 293         int ret = IRQ_NONE;
 294
 295         spin_lock(&suspended_lock);
 296         rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
 297         if (rtsr) {             /* this interrupt is shared!  Is it ours? */
 298                 if (rtsr & AT91_RTC_ALARM)
 299                         events |= (RTC_AF | RTC_IRQF);
 300                 if (rtsr & AT91_RTC_SECEV) {
 301                         complete(&at91_rtc_upd_rdy);
 302                         at91_rtc_write_idr(AT91_RTC_SECEV);
 303                 }
 304                 if (rtsr & AT91_RTC_ACKUPD)
 305                         complete(&at91_rtc_updated);
 306
 307                 at91_rtc_write(AT91_RTC_SCCR, rtsr);    /* clear status reg */
 308
 309                 if (!suspended) {
 310                         rtc_update_irq(rtc, 1, events);
 311
 312                         dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n",
 313                                 __func__, events >> 8, events & 0x000000FF);
 314                 } else {
 315                         cached_events |= events;
 316                         at91_rtc_write_idr(at91_rtc_imr);
 317                         pm_system_wakeup();
 318                 }
 319
 320                 ret = IRQ_HANDLED;
 321         }
 322         spin_unlock(&suspended_lock);
 323
 324         return ret;
 325 }
 326
 327 static const struct at91_rtc_config at91rm9200_config = {
 328 };
 329
 330 static const struct at91_rtc_config at91sam9x5_config = {
 331         .use_shadow_imr = true,
 332 };
 333
 334 #ifdef CONFIG_OF
 335 static const struct of_device_id at91_rtc_dt_ids[] = {
 336         {
 337                 .compatible = "atmel,at91rm9200-rtc",
 338                 .data = &at91rm9200_config,
 339         }, {
 340                 .compatible = "atmel,at91sam9x5-rtc",
 341                 .data = &at91sam9x5_config,
 342         }, {
 343                 /* sentinel */
 344         }
 345 };
 346 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
 347 #endif
 348
 349 static const struct at91_rtc_config *
 350 at91_rtc_get_config(struct platform_device *pdev)
 351 {
 352         const struct of_device_id *match;
 353
 354         if (pdev->dev.of_node) {
 355                 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
 356                 if (!match)
 357                         return NULL;
 358                 return (const struct at91_rtc_config *)match->data;
 359         }
 360
 361         return &at91rm9200_config;
 362 }
 363
 364 static const struct rtc_class_ops at91_rtc_ops = {
 365         .read_time      = at91_rtc_readtime,
 366         .set_time       = at91_rtc_settime,
 367         .read_alarm     = at91_rtc_readalarm,
 368         .set_alarm      = at91_rtc_setalarm,
 369         .proc           = at91_rtc_proc,
 370         .alarm_irq_enable = at91_rtc_alarm_irq_enable,
 371 };
 372
 373 /*
 374  * Initialize and install RTC driver
 375  */
 376 static int __init at91_rtc_probe(struct platform_device *pdev)
 377 {
 378         struct rtc_device *rtc;
 379         struct resource *regs;
 380         int ret = 0;
 381
 382         at91_rtc_config = at91_rtc_get_config(pdev);
 383         if (!at91_rtc_config)
 384                 return -ENODEV;
 385
 386         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 387         if (!regs) {
 388                 dev_err(&pdev->dev, "no mmio resource defined\n");
 389                 return -ENXIO;
 390         }
 391
 392         irq = platform_get_irq(pdev, 0);
 393         if (irq < 0) {
 394                 dev_err(&pdev->dev, "no irq resource defined\n");
 395                 return -ENXIO;
 396         }
 397
 398         at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start,
 399                                      resource_size(regs));
 400         if (!at91_rtc_regs) {
 401                 dev_err(&pdev->dev, "failed to map registers, aborting.\n");
 402                 return -ENOMEM;
 403         }
 404
 405         rtc = devm_rtc_allocate_device(&pdev->dev);
 406         if (IS_ERR(rtc))
 407                 return PTR_ERR(rtc);
 408         platform_set_drvdata(pdev, rtc);
 409
 410         sclk = devm_clk_get(&pdev->dev, NULL);
 411         if (IS_ERR(sclk))
 412                 return PTR_ERR(sclk);
 413
 414         ret = clk_prepare_enable(sclk);
 415         if (ret) {
 416                 dev_err(&pdev->dev, "Could not enable slow clock\n");
 417                 return ret;
 418         }
 419
 420         at91_rtc_write(AT91_RTC_CR, 0);
 421         at91_rtc_write(AT91_RTC_MR, 0);         /* 24 hour mode */
 422
 423         /* Disable all interrupts */
 424         at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 425                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 426                                         AT91_RTC_CALEV);
 427
 428         ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt,
 429                                IRQF_SHARED | IRQF_COND_SUSPEND,
 430                                "at91_rtc", pdev);
 431         if (ret) {
 432                 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
 433                 goto err_clk;
 434         }
 435
 436         /* cpu init code should really have flagged this device as
 437          * being wake-capable; if it didn't, do that here.
 438          */
 439         if (!device_can_wakeup(&pdev->dev))
 440                 device_init_wakeup(&pdev->dev, 1);
 441
 442         rtc->ops = &at91_rtc_ops;
 443         rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
 444         rtc->range_max = RTC_TIMESTAMP_END_2099;
 445         ret = rtc_register_device(rtc);
 446         if (ret)
 447                 goto err_clk;
 448
 449         /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
 450          * completion.
 451          */
 452         at91_rtc_write_ier(AT91_RTC_SECEV);
 453
 454         dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
 455         return 0;
 456
 457 err_clk:
 458         clk_disable_unprepare(sclk);
 459
 460         return ret;
 461 }
 462
 463 /*
 464  * Disable and remove the RTC driver
 465  */
 466 static int __exit at91_rtc_remove(struct platform_device *pdev)
 467 {
 468         /* Disable all interrupts */
 469         at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 470                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 471                                         AT91_RTC_CALEV);
 472
 473         clk_disable_unprepare(sclk);
 474
 475         return 0;
 476 }
 477
 478 static void at91_rtc_shutdown(struct platform_device *pdev)
 479 {
 480         /* Disable all interrupts */
 481         at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 482                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 483                                         AT91_RTC_CALEV);
 484 }
 485
 486 #ifdef CONFIG_PM_SLEEP
 487
 488 /* AT91RM9200 RTC Power management control */
 489
 490 static int at91_rtc_suspend(struct device *dev)
 491 {
 492         /* this IRQ is shared with DBGU and other hardware which isn't
 493          * necessarily doing PM like we are...
 494          */
 495         at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 496
 497         at91_rtc_imr = at91_rtc_read_imr()
 498                         & (AT91_RTC_ALARM|AT91_RTC_SECEV);
 499         if (at91_rtc_imr) {
 500                 if (device_may_wakeup(dev)) {
 501                         unsigned long flags;
 502
 503                         enable_irq_wake(irq);
 504
 505                         spin_lock_irqsave(&suspended_lock, flags);
 506                         suspended = true;
 507                         spin_unlock_irqrestore(&suspended_lock, flags);
 508                 } else {
 509                         at91_rtc_write_idr(at91_rtc_imr);
 510                 }
 511         }
 512         return 0;
 513 }
 514
 515 static int at91_rtc_resume(struct device *dev)
 516 {
 517         struct rtc_device *rtc = dev_get_drvdata(dev);
 518
 519         if (at91_rtc_imr) {
 520                 if (device_may_wakeup(dev)) {
 521                         unsigned long flags;
 522
 523                         spin_lock_irqsave(&suspended_lock, flags);
 524
 525                         if (cached_events) {
 526                                 rtc_update_irq(rtc, 1, cached_events);
 527                                 cached_events = 0;
 528                         }
 529
 530                         suspended = false;
 531                         spin_unlock_irqrestore(&suspended_lock, flags);
 532
 533                         disable_irq_wake(irq);
 534                 }
 535                 at91_rtc_write_ier(at91_rtc_imr);
 536         }
 537         return 0;
 538 }
 539 #endif
 540
 541 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
 542
 543 static struct platform_driver at91_rtc_driver = {
 544         .remove         = __exit_p(at91_rtc_remove),
 545         .shutdown       = at91_rtc_shutdown,
 546         .driver         = {
 547                 .name   = "at91_rtc",
 548                 .pm     = &at91_rtc_pm_ops,
 549                 .of_match_table = of_match_ptr(at91_rtc_dt_ids),
 550         },
 551 };
 552
 553 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
 554
 555 MODULE_AUTHOR("Rick Bronson");
 556 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
 557 MODULE_LICENSE("GPL");
 558 MODULE_ALIAS("platform:at91_rtc");