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