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 DECLARE_COMPLETION(at91_rtc_upd_rdy);
  52 static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
  53 static void __iomem *at91_rtc_regs;
  54 static int irq;
  55 static DEFINE_SPINLOCK(at91_rtc_lock);
  56 static u32 at91_rtc_shadow_imr;
  57
  58 static void at91_rtc_write_ier(u32 mask)
  59 {
  60         unsigned long flags;
  61
  62         spin_lock_irqsave(&at91_rtc_lock, flags);
  63         at91_rtc_shadow_imr |= mask;
  64         at91_rtc_write(AT91_RTC_IER, mask);
  65         spin_unlock_irqrestore(&at91_rtc_lock, flags);
  66 }
  67
  68 static void at91_rtc_write_idr(u32 mask)
  69 {
  70         unsigned long flags;
  71
  72         spin_lock_irqsave(&at91_rtc_lock, flags);
  73         at91_rtc_write(AT91_RTC_IDR, mask);
  74         /*
  75          * Register read back (of any RTC-register) needed to make sure
  76          * IDR-register write has reached the peripheral before updating
  77          * shadow mask.
  78          *
  79          * Note that there is still a possibility that the mask is updated
  80          * before interrupts have actually been disabled in hardware. The only
  81          * way to be certain would be to poll the IMR-register, which is is
  82          * the very register we are trying to emulate. The register read back
  83          * is a reasonable heuristic.
  84          */
  85         at91_rtc_read(AT91_RTC_SR);
  86         at91_rtc_shadow_imr &= ~mask;
  87         spin_unlock_irqrestore(&at91_rtc_lock, flags);
  88 }
  89
  90 static u32 at91_rtc_read_imr(void)
  91 {
  92         unsigned long flags;
  93         u32 mask;
  94
  95         if (at91_rtc_config->use_shadow_imr) {
  96                 spin_lock_irqsave(&at91_rtc_lock, flags);
  97                 mask = at91_rtc_shadow_imr;
  98                 spin_unlock_irqrestore(&at91_rtc_lock, flags);
  99         } else {
 100                 mask = at91_rtc_read(AT91_RTC_IMR);
 101         }
 102
 103         return mask;
 104 }
 105
 106 /*
 107  * Decode time/date into rtc_time structure
 108  */
 109 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
 110                                 struct rtc_time *tm)
 111 {
 112         unsigned int time, date;
 113
 114         /* must read twice in case it changes */
 115         do {
 116                 time = at91_rtc_read(timereg);
 117                 date = at91_rtc_read(calreg);
 118         } while ((time != at91_rtc_read(timereg)) ||
 119                         (date != at91_rtc_read(calreg)));
 120
 121         tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
 122         tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
 123         tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
 124
 125         /*
 126          * The Calendar Alarm register does not have a field for
 127          * the year - so these will return an invalid value.  When an
 128          * alarm is set, at91_alarm_year will store the current year.
 129          */
 130         tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;     /* century */
 131         tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);    /* year */
 132
 133         tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
 134         tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
 135         tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
 136 }
 137
 138 /*
 139  * Read current time and date in RTC
 140  */
 141 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
 142 {
 143         at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
 144         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 145         tm->tm_year = tm->tm_year - 1900;
 146
 147         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 148                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 149                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 150
 151         return 0;
 152 }
 153
 154 /*
 155  * Set current time and date in RTC
 156  */
 157 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
 158 {
 159         unsigned long cr;
 160
 161         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 162                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 163                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 164
 165         wait_for_completion(&at91_rtc_upd_rdy);
 166
 167         /* Stop Time/Calendar from counting */
 168         cr = at91_rtc_read(AT91_RTC_CR);
 169         at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
 170
 171         at91_rtc_write_ier(AT91_RTC_ACKUPD);
 172         wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
 173         at91_rtc_write_idr(AT91_RTC_ACKUPD);
 174
 175         at91_rtc_write(AT91_RTC_TIMR,
 176                           bin2bcd(tm->tm_sec) << 0
 177                         | bin2bcd(tm->tm_min) << 8
 178                         | bin2bcd(tm->tm_hour) << 16);
 179
 180         at91_rtc_write(AT91_RTC_CALR,
 181                           bin2bcd((tm->tm_year + 1900) / 100)   /* century */
 182                         | bin2bcd(tm->tm_year % 100) << 8       /* year */
 183                         | bin2bcd(tm->tm_mon + 1) << 16         /* tm_mon starts at zero */
 184                         | bin2bcd(tm->tm_wday + 1) << 21        /* day of the week [0-6], Sunday=0 */
 185                         | bin2bcd(tm->tm_mday) << 24);
 186
 187         /* Restart Time/Calendar */
 188         cr = at91_rtc_read(AT91_RTC_CR);
 189         at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
 190         at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
 191         at91_rtc_write_ier(AT91_RTC_SECEV);
 192
 193         return 0;
 194 }
 195
 196 /*
 197  * Read alarm time and date in RTC
 198  */
 199 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 200 {
 201         struct rtc_time *tm = &alrm->time;
 202
 203         at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
 204         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 205         tm->tm_year = at91_alarm_year - 1900;
 206
 207         alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
 208                         ? 1 : 0;
 209
 210         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 211                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 212                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 213
 214         return 0;
 215 }
 216
 217 /*
 218  * Set alarm time and date in RTC
 219  */
 220 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 221 {
 222         struct rtc_time tm;
 223
 224         at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
 225
 226         at91_alarm_year = tm.tm_year;
 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                 at91_alarm_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
 294         rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
 295         if (rtsr) {             /* this interrupt is shared!  Is it ours? */
 296                 if (rtsr & AT91_RTC_ALARM)
 297                         events |= (RTC_AF | RTC_IRQF);
 298                 if (rtsr & AT91_RTC_SECEV) {
 299                         complete(&at91_rtc_upd_rdy);
 300                         at91_rtc_write_idr(AT91_RTC_SECEV);
 301                 }
 302                 if (rtsr & AT91_RTC_ACKUPD)
 303                         complete(&at91_rtc_updated);
 304
 305                 at91_rtc_write(AT91_RTC_SCCR, rtsr);    /* clear status reg */
 306
 307                 rtc_update_irq(rtc, 1, events);
 308
 309                 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", __func__,
 310                         events >> 8, events & 0x000000FF);
 311
 312                 return IRQ_HANDLED;
 313         }
 314         return IRQ_NONE;                /* not handled */
 315 }
 316
 317 static const struct at91_rtc_config at91rm9200_config = {
 318 };
 319
 320 static const struct at91_rtc_config at91sam9x5_config = {
 321         .use_shadow_imr = true,
 322 };
 323
 324 #ifdef CONFIG_OF
 325 static const struct of_device_id at91_rtc_dt_ids[] = {
 326         {
 327                 .compatible = "atmel,at91rm9200-rtc",
 328                 .data = &at91rm9200_config,
 329         }, {
 330                 .compatible = "atmel,at91sam9x5-rtc",
 331                 .data = &at91sam9x5_config,
 332         }, {
 333                 /* sentinel */
 334         }
 335 };
 336 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
 337 #endif
 338
 339 static const struct at91_rtc_config *
 340 at91_rtc_get_config(struct platform_device *pdev)
 341 {
 342         const struct of_device_id *match;
 343
 344         if (pdev->dev.of_node) {
 345                 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
 346                 if (!match)
 347                         return NULL;
 348                 return (const struct at91_rtc_config *)match->data;
 349         }
 350
 351         return &at91rm9200_config;
 352 }
 353
 354 static const struct rtc_class_ops at91_rtc_ops = {
 355         .read_time      = at91_rtc_readtime,
 356         .set_time       = at91_rtc_settime,
 357         .read_alarm     = at91_rtc_readalarm,
 358         .set_alarm      = at91_rtc_setalarm,
 359         .proc           = at91_rtc_proc,
 360         .alarm_irq_enable = at91_rtc_alarm_irq_enable,
 361 };
 362
 363 /*
 364  * Initialize and install RTC driver
 365  */
 366 static int __init at91_rtc_probe(struct platform_device *pdev)
 367 {
 368         struct rtc_device *rtc;
 369         struct resource *regs;
 370         int ret = 0;
 371
 372         at91_rtc_config = at91_rtc_get_config(pdev);
 373         if (!at91_rtc_config)
 374                 return -ENODEV;
 375
 376         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 377         if (!regs) {
 378                 dev_err(&pdev->dev, "no mmio resource defined\n");
 379                 return -ENXIO;
 380         }
 381
 382         irq = platform_get_irq(pdev, 0);
 383         if (irq < 0) {
 384                 dev_err(&pdev->dev, "no irq resource defined\n");
 385                 return -ENXIO;
 386         }
 387
 388         at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start,
 389                                      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 = devm_request_irq(&pdev->dev, 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                 return ret;
 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 = devm_rtc_device_register(&pdev->dev, pdev->name,
 418                                 &at91_rtc_ops, THIS_MODULE);
 419         if (IS_ERR(rtc))
 420                 return PTR_ERR(rtc);
 421         platform_set_drvdata(pdev, rtc);
 422
 423         /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
 424          * completion.
 425          */
 426         at91_rtc_write_ier(AT91_RTC_SECEV);
 427
 428         dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
 429         return 0;
 430 }
 431
 432 /*
 433  * Disable and remove the RTC driver
 434  */
 435 static int __exit at91_rtc_remove(struct platform_device *pdev)
 436 {
 437         /* Disable all interrupts */
 438         at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 439                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 440                                         AT91_RTC_CALEV);
 441
 442         return 0;
 443 }
 444
 445 static void at91_rtc_shutdown(struct platform_device *pdev)
 446 {
 447         /* Disable all interrupts */
 448         at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 449                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 450                                         AT91_RTC_CALEV);
 451 }
 452
 453 #ifdef CONFIG_PM_SLEEP
 454
 455 /* AT91RM9200 RTC Power management control */
 456
 457 static u32 at91_rtc_imr;
 458
 459 static int at91_rtc_suspend(struct device *dev)
 460 {
 461         /* this IRQ is shared with DBGU and other hardware which isn't
 462          * necessarily doing PM like we are...
 463          */
 464         at91_rtc_imr = at91_rtc_read_imr()
 465                         & (AT91_RTC_ALARM|AT91_RTC_SECEV);
 466         if (at91_rtc_imr) {
 467                 if (device_may_wakeup(dev))
 468                         enable_irq_wake(irq);
 469                 else
 470                         at91_rtc_write_idr(at91_rtc_imr);
 471         }
 472         return 0;
 473 }
 474
 475 static int at91_rtc_resume(struct device *dev)
 476 {
 477         if (at91_rtc_imr) {
 478                 if (device_may_wakeup(dev))
 479                         disable_irq_wake(irq);
 480                 else
 481                         at91_rtc_write_ier(at91_rtc_imr);
 482         }
 483         return 0;
 484 }
 485 #endif
 486
 487 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
 488
 489 static struct platform_driver at91_rtc_driver = {
 490         .remove         = __exit_p(at91_rtc_remove),
 491         .shutdown       = at91_rtc_shutdown,
 492         .driver         = {
 493                 .name   = "at91_rtc",
 494                 .owner  = THIS_MODULE,
 495                 .pm     = &at91_rtc_pm_ops,
 496                 .of_match_table = of_match_ptr(at91_rtc_dt_ids),
 497         },
 498 };
 499
 500 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
 501
 502 MODULE_AUTHOR("Rick Bronson");
 503 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
 504 MODULE_LICENSE("GPL");
 505 MODULE_ALIAS("platform:at91_rtc");