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