drivers/rtc/rtc-omap.c

   1 /*
   2  * TI OMAP1 Real Time Clock interface for Linux
   3  *
   4  * Copyright (C) 2003 MontaVista Software, Inc.
   5  * Author: George G. Davis <gdavis@mvista.com> or <source@mvista.com>
   6  *
   7  * Copyright (C) 2006 David Brownell (new RTC framework)
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version
  12  * 2 of the License, or (at your option) any later version.
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/ioport.h>
  19 #include <linux/delay.h>
  20 #include <linux/rtc.h>
  21 #include <linux/bcd.h>
  22 #include <linux/platform_device.h>
  23
  24 #include <asm/io.h>
  25 #include <asm/mach/time.h>
  26
  27
  28 /* The OMAP1 RTC is a year/month/day/hours/minutes/seconds BCD clock
  29  * with century-range alarm matching, driven by the 32kHz clock.
  30  *
  31  * The main user-visible ways it differs from PC RTCs are by omitting
  32  * "don't care" alarm fields and sub-second periodic IRQs, and having
  33  * an autoadjust mechanism to calibrate to the true oscillator rate.
  34  *
  35  * Board-specific wiring options include using split power mode with
  36  * RTC_OFF_NOFF used as the reset signal (so the RTC won't be reset),
  37  * and wiring RTC_WAKE_INT (so the RTC alarm can wake the system from
  38  * low power modes).  See the BOARD-SPECIFIC CUSTOMIZATION comment.
  39  */
  40
  41 #define OMAP_RTC_BASE                   0xfffb4800
  42
  43 /* RTC registers */
  44 #define OMAP_RTC_SECONDS_REG            0x00
  45 #define OMAP_RTC_MINUTES_REG            0x04
  46 #define OMAP_RTC_HOURS_REG              0x08
  47 #define OMAP_RTC_DAYS_REG               0x0C
  48 #define OMAP_RTC_MONTHS_REG             0x10
  49 #define OMAP_RTC_YEARS_REG              0x14
  50 #define OMAP_RTC_WEEKS_REG              0x18
  51
  52 #define OMAP_RTC_ALARM_SECONDS_REG      0x20
  53 #define OMAP_RTC_ALARM_MINUTES_REG      0x24
  54 #define OMAP_RTC_ALARM_HOURS_REG        0x28
  55 #define OMAP_RTC_ALARM_DAYS_REG         0x2c
  56 #define OMAP_RTC_ALARM_MONTHS_REG       0x30
  57 #define OMAP_RTC_ALARM_YEARS_REG        0x34
  58
  59 #define OMAP_RTC_CTRL_REG               0x40
  60 #define OMAP_RTC_STATUS_REG             0x44
  61 #define OMAP_RTC_INTERRUPTS_REG         0x48
  62
  63 #define OMAP_RTC_COMP_LSB_REG           0x4c
  64 #define OMAP_RTC_COMP_MSB_REG           0x50
  65 #define OMAP_RTC_OSC_REG                0x54
  66
  67 /* OMAP_RTC_CTRL_REG bit fields: */
  68 #define OMAP_RTC_CTRL_SPLIT             (1<<7)
  69 #define OMAP_RTC_CTRL_DISABLE           (1<<6)
  70 #define OMAP_RTC_CTRL_SET_32_COUNTER    (1<<5)
  71 #define OMAP_RTC_CTRL_TEST              (1<<4)
  72 #define OMAP_RTC_CTRL_MODE_12_24        (1<<3)
  73 #define OMAP_RTC_CTRL_AUTO_COMP         (1<<2)
  74 #define OMAP_RTC_CTRL_ROUND_30S         (1<<1)
  75 #define OMAP_RTC_CTRL_STOP              (1<<0)
  76
  77 /* OMAP_RTC_STATUS_REG bit fields: */
  78 #define OMAP_RTC_STATUS_POWER_UP        (1<<7)
  79 #define OMAP_RTC_STATUS_ALARM           (1<<6)
  80 #define OMAP_RTC_STATUS_1D_EVENT        (1<<5)
  81 #define OMAP_RTC_STATUS_1H_EVENT        (1<<4)
  82 #define OMAP_RTC_STATUS_1M_EVENT        (1<<3)
  83 #define OMAP_RTC_STATUS_1S_EVENT        (1<<2)
  84 #define OMAP_RTC_STATUS_RUN             (1<<1)
  85 #define OMAP_RTC_STATUS_BUSY            (1<<0)
  86
  87 /* OMAP_RTC_INTERRUPTS_REG bit fields: */
  88 #define OMAP_RTC_INTERRUPTS_IT_ALARM    (1<<3)
  89 #define OMAP_RTC_INTERRUPTS_IT_TIMER    (1<<2)
  90
  91
  92 #define rtc_read(addr)          omap_readb(OMAP_RTC_BASE + (addr))
  93 #define rtc_write(val, addr)    omap_writeb(val, OMAP_RTC_BASE + (addr))
  94
  95
  96 /* platform_bus isn't hotpluggable, so for static linkage it'd be safe
  97  * to get rid of probe() and remove() code ... too bad the driver struct
  98  * remembers probe(), that's about 25% of the runtime footprint!!
  99  */
 100 #ifndef MODULE
 101 #undef  __devexit
 102 #undef  __devexit_p
 103 #define __devexit       __exit
 104 #define __devexit_p     __exit_p
 105 #endif
 106
 107
 108 /* we rely on the rtc framework to handle locking (rtc->ops_lock),
 109  * so the only other requirement is that register accesses which
 110  * require BUSY to be clear are made with IRQs locally disabled
 111  */
 112 static void rtc_wait_not_busy(void)
 113 {
 114         int     count = 0;
 115         u8      status;
 116
 117         /* BUSY may stay active for 1/32768 second (~30 usec) */
 118         for (count = 0; count < 50; count++) {
 119                 status = rtc_read(OMAP_RTC_STATUS_REG);
 120                 if ((status & (u8)OMAP_RTC_STATUS_BUSY) == 0)
 121                         break;
 122                 udelay(1);
 123         }
 124         /* now we have ~15 usec to read/write various registers */
 125 }
 126
 127 static irqreturn_t rtc_irq(int irq, void *rtc)
 128 {
 129         unsigned long           events = 0;
 130         u8                      irq_data;
 131
 132         irq_data = rtc_read(OMAP_RTC_STATUS_REG);
 133
 134         /* alarm irq? */
 135         if (irq_data & OMAP_RTC_STATUS_ALARM) {
 136                 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
 137                 events |= RTC_IRQF | RTC_AF;
 138         }
 139
 140         /* 1/sec periodic/update irq? */
 141         if (irq_data & OMAP_RTC_STATUS_1S_EVENT)
 142                 events |= RTC_IRQF | RTC_UF;
 143
 144         rtc_update_irq(rtc, 1, events);
 145
 146         return IRQ_HANDLED;
 147 }
 148
 149 #ifdef  CONFIG_RTC_INTF_DEV
 150
 151 static int
 152 omap_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 153 {
 154         u8 reg;
 155
 156         switch (cmd) {
 157         case RTC_AIE_OFF:
 158         case RTC_AIE_ON:
 159         case RTC_UIE_OFF:
 160         case RTC_UIE_ON:
 161                 break;
 162         default:
 163                 return -ENOIOCTLCMD;
 164         }
 165
 166         local_irq_disable();
 167         rtc_wait_not_busy();
 168         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 169         switch (cmd) {
 170         /* AIE = Alarm Interrupt Enable */
 171         case RTC_AIE_OFF:
 172                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 173                 break;
 174         case RTC_AIE_ON:
 175                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 176                 break;
 177         /* UIE = Update Interrupt Enable (1/second) */
 178         case RTC_UIE_OFF:
 179                 reg &= ~OMAP_RTC_INTERRUPTS_IT_TIMER;
 180                 break;
 181         case RTC_UIE_ON:
 182                 reg |= OMAP_RTC_INTERRUPTS_IT_TIMER;
 183                 break;
 184         }
 185         rtc_wait_not_busy();
 186         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 187         local_irq_enable();
 188
 189         return 0;
 190 }
 191
 192 #else
 193 #define omap_rtc_ioctl  NULL
 194 #endif
 195
 196 /* this hardware doesn't support "don't care" alarm fields */
 197 static int tm2bcd(struct rtc_time *tm)
 198 {
 199         if (rtc_valid_tm(tm) != 0)
 200                 return -EINVAL;
 201
 202         tm->tm_sec = BIN2BCD(tm->tm_sec);
 203         tm->tm_min = BIN2BCD(tm->tm_min);
 204         tm->tm_hour = BIN2BCD(tm->tm_hour);
 205         tm->tm_mday = BIN2BCD(tm->tm_mday);
 206
 207         tm->tm_mon = BIN2BCD(tm->tm_mon + 1);
 208
 209         /* epoch == 1900 */
 210         if (tm->tm_year < 100 || tm->tm_year > 199)
 211                 return -EINVAL;
 212         tm->tm_year = BIN2BCD(tm->tm_year - 100);
 213
 214         return 0;
 215 }
 216
 217 static void bcd2tm(struct rtc_time *tm)
 218 {
 219         tm->tm_sec = BCD2BIN(tm->tm_sec);
 220         tm->tm_min = BCD2BIN(tm->tm_min);
 221         tm->tm_hour = BCD2BIN(tm->tm_hour);
 222         tm->tm_mday = BCD2BIN(tm->tm_mday);
 223         tm->tm_mon = BCD2BIN(tm->tm_mon) - 1;
 224         /* epoch == 1900 */
 225         tm->tm_year = BCD2BIN(tm->tm_year) + 100;
 226 }
 227
 228
 229 static int omap_rtc_read_time(struct device *dev, struct rtc_time *tm)
 230 {
 231         /* we don't report wday/yday/isdst ... */
 232         local_irq_disable();
 233         rtc_wait_not_busy();
 234
 235         tm->tm_sec = rtc_read(OMAP_RTC_SECONDS_REG);
 236         tm->tm_min = rtc_read(OMAP_RTC_MINUTES_REG);
 237         tm->tm_hour = rtc_read(OMAP_RTC_HOURS_REG);
 238         tm->tm_mday = rtc_read(OMAP_RTC_DAYS_REG);
 239         tm->tm_mon = rtc_read(OMAP_RTC_MONTHS_REG);
 240         tm->tm_year = rtc_read(OMAP_RTC_YEARS_REG);
 241
 242         local_irq_enable();
 243
 244         bcd2tm(tm);
 245         return 0;
 246 }
 247
 248 static int omap_rtc_set_time(struct device *dev, struct rtc_time *tm)
 249 {
 250         if (tm2bcd(tm) < 0)
 251                 return -EINVAL;
 252         local_irq_disable();
 253         rtc_wait_not_busy();
 254
 255         rtc_write(tm->tm_year, OMAP_RTC_YEARS_REG);
 256         rtc_write(tm->tm_mon, OMAP_RTC_MONTHS_REG);
 257         rtc_write(tm->tm_mday, OMAP_RTC_DAYS_REG);
 258         rtc_write(tm->tm_hour, OMAP_RTC_HOURS_REG);
 259         rtc_write(tm->tm_min, OMAP_RTC_MINUTES_REG);
 260         rtc_write(tm->tm_sec, OMAP_RTC_SECONDS_REG);
 261
 262         local_irq_enable();
 263
 264         return 0;
 265 }
 266
 267 static int omap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 268 {
 269         local_irq_disable();
 270         rtc_wait_not_busy();
 271
 272         alm->time.tm_sec = rtc_read(OMAP_RTC_ALARM_SECONDS_REG);
 273         alm->time.tm_min = rtc_read(OMAP_RTC_ALARM_MINUTES_REG);
 274         alm->time.tm_hour = rtc_read(OMAP_RTC_ALARM_HOURS_REG);
 275         alm->time.tm_mday = rtc_read(OMAP_RTC_ALARM_DAYS_REG);
 276         alm->time.tm_mon = rtc_read(OMAP_RTC_ALARM_MONTHS_REG);
 277         alm->time.tm_year = rtc_read(OMAP_RTC_ALARM_YEARS_REG);
 278
 279         local_irq_enable();
 280
 281         bcd2tm(&alm->time);
 282         alm->enabled = !!(rtc_read(OMAP_RTC_INTERRUPTS_REG)
 283                         & OMAP_RTC_INTERRUPTS_IT_ALARM);
 284
 285         return 0;
 286 }
 287
 288 static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 289 {
 290         u8 reg;
 291
 292         if (tm2bcd(&alm->time) < 0)
 293                 return -EINVAL;
 294
 295         local_irq_disable();
 296         rtc_wait_not_busy();
 297
 298         rtc_write(alm->time.tm_year, OMAP_RTC_ALARM_YEARS_REG);
 299         rtc_write(alm->time.tm_mon, OMAP_RTC_ALARM_MONTHS_REG);
 300         rtc_write(alm->time.tm_mday, OMAP_RTC_ALARM_DAYS_REG);
 301         rtc_write(alm->time.tm_hour, OMAP_RTC_ALARM_HOURS_REG);
 302         rtc_write(alm->time.tm_min, OMAP_RTC_ALARM_MINUTES_REG);
 303         rtc_write(alm->time.tm_sec, OMAP_RTC_ALARM_SECONDS_REG);
 304
 305         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 306         if (alm->enabled)
 307                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 308         else
 309                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 310         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 311
 312         local_irq_enable();
 313
 314         return 0;
 315 }
 316
 317 static struct rtc_class_ops omap_rtc_ops = {
 318         .ioctl          = omap_rtc_ioctl,
 319         .read_time      = omap_rtc_read_time,
 320         .set_time       = omap_rtc_set_time,
 321         .read_alarm     = omap_rtc_read_alarm,
 322         .set_alarm      = omap_rtc_set_alarm,
 323 };
 324
 325 static int omap_rtc_alarm;
 326 static int omap_rtc_timer;
 327
 328 static int __devinit omap_rtc_probe(struct platform_device *pdev)
 329 {
 330         struct resource         *res, *mem;
 331         struct rtc_device       *rtc;
 332         u8                      reg, new_ctrl;
 333
 334         omap_rtc_timer = platform_get_irq(pdev, 0);
 335         if (omap_rtc_timer <= 0) {
 336                 pr_debug("%s: no update irq?\n", pdev->name);
 337                 return -ENOENT;
 338         }
 339
 340         omap_rtc_alarm = platform_get_irq(pdev, 1);
 341         if (omap_rtc_alarm <= 0) {
 342                 pr_debug("%s: no alarm irq?\n", pdev->name);
 343                 return -ENOENT;
 344         }
 345
 346         /* NOTE:  using static mapping for RTC registers */
 347         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 348         if (res && res->start != OMAP_RTC_BASE) {
 349                 pr_debug("%s: RTC registers at %08x, expected %08x\n",
 350                         pdev->name, (unsigned) res->start, OMAP_RTC_BASE);
 351                 return -ENOENT;
 352         }
 353
 354         if (res)
 355                 mem = request_mem_region(res->start,
 356                                 res->end - res->start + 1,
 357                                 pdev->name);
 358         else
 359                 mem = NULL;
 360         if (!mem) {
 361                 pr_debug("%s: RTC registers at %08x are not free\n",
 362                         pdev->name, OMAP_RTC_BASE);
 363                 return -EBUSY;
 364         }
 365
 366         rtc = rtc_device_register(pdev->name, &pdev->dev,
 367                         &omap_rtc_ops, THIS_MODULE);
 368         if (IS_ERR(rtc)) {
 369                 pr_debug("%s: can't register RTC device, err %ld\n",
 370                         pdev->name, PTR_ERR(rtc));
 371                 goto fail;
 372         }
 373         platform_set_drvdata(pdev, rtc);
 374         dev_set_drvdata(&rtc->dev, mem);
 375
 376         /* clear pending irqs, and set 1/second periodic,
 377          * which we'll use instead of update irqs
 378          */
 379         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 380
 381         /* clear old status */
 382         reg = rtc_read(OMAP_RTC_STATUS_REG);
 383         if (reg & (u8) OMAP_RTC_STATUS_POWER_UP) {
 384                 pr_info("%s: RTC power up reset detected\n",
 385                         pdev->name);
 386                 rtc_write(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG);
 387         }
 388         if (reg & (u8) OMAP_RTC_STATUS_ALARM)
 389                 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
 390
 391         /* handle periodic and alarm irqs */
 392         if (request_irq(omap_rtc_timer, rtc_irq, IRQF_DISABLED,
 393                         rtc->dev.bus_id, rtc)) {
 394                 pr_debug("%s: RTC timer interrupt IRQ%d already claimed\n",
 395                         pdev->name, omap_rtc_timer);
 396                 goto fail0;
 397         }
 398         if (request_irq(omap_rtc_alarm, rtc_irq, IRQF_DISABLED,
 399                         rtc->dev.bus_id, rtc)) {
 400                 pr_debug("%s: RTC alarm interrupt IRQ%d already claimed\n",
 401                         pdev->name, omap_rtc_alarm);
 402                 goto fail1;
 403         }
 404
 405         /* On boards with split power, RTC_ON_NOFF won't reset the RTC */
 406         reg = rtc_read(OMAP_RTC_CTRL_REG);
 407         if (reg & (u8) OMAP_RTC_CTRL_STOP)
 408                 pr_info("%s: already running\n", pdev->name);
 409
 410         /* force to 24 hour mode */
 411         new_ctrl = reg & ~(OMAP_RTC_CTRL_SPLIT|OMAP_RTC_CTRL_AUTO_COMP);
 412         new_ctrl |= OMAP_RTC_CTRL_STOP;
 413
 414         /* BOARD-SPECIFIC CUSTOMIZATION CAN GO HERE:
 415          *
 416          *  - Boards wired so that RTC_WAKE_INT does something, and muxed
 417          *    right (W13_1610_RTC_WAKE_INT is the default after chip reset),
 418          *    should initialize the device wakeup flag appropriately.
 419          *
 420          *  - Boards wired so RTC_ON_nOFF is used as the reset signal,
 421          *    rather than nPWRON_RESET, should forcibly enable split
 422          *    power mode.  (Some chip errata report that RTC_CTRL_SPLIT
 423          *    is write-only, and always reads as zero...)
 424          */
 425         device_init_wakeup(&pdev->dev, 0);
 426
 427         if (new_ctrl & (u8) OMAP_RTC_CTRL_SPLIT)
 428                 pr_info("%s: split power mode\n", pdev->name);
 429
 430         if (reg != new_ctrl)
 431                 rtc_write(new_ctrl, OMAP_RTC_CTRL_REG);
 432
 433         return 0;
 434
 435 fail1:
 436         free_irq(omap_rtc_timer, NULL);
 437 fail0:
 438         rtc_device_unregister(rtc);
 439 fail:
 440         release_resource(mem);
 441         return -EIO;
 442 }
 443
 444 static int __devexit omap_rtc_remove(struct platform_device *pdev)
 445 {
 446         struct rtc_device       *rtc = platform_get_drvdata(pdev);;
 447
 448         device_init_wakeup(&pdev->dev, 0);
 449
 450         /* leave rtc running, but disable irqs */
 451         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 452
 453         free_irq(omap_rtc_timer, rtc);
 454         free_irq(omap_rtc_alarm, rtc);
 455
 456         release_resource(dev_get_drvdata(&rtc->dev));
 457         rtc_device_unregister(rtc);
 458         return 0;
 459 }
 460
 461 #ifdef CONFIG_PM
 462
 463 static u8 irqstat;
 464
 465 static int omap_rtc_suspend(struct platform_device *pdev, pm_message_t state)
 466 {
 467         irqstat = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 468
 469         /* FIXME the RTC alarm is not currently acting as a wakeup event
 470          * source, and in fact this enable() call is just saving a flag
 471          * that's never used...
 472          */
 473         if (device_may_wakeup(&pdev->dev))
 474                 enable_irq_wake(omap_rtc_alarm);
 475         else
 476                 rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 477
 478         return 0;
 479 }
 480
 481 static int omap_rtc_resume(struct platform_device *pdev)
 482 {
 483         if (device_may_wakeup(&pdev->dev))
 484                 disable_irq_wake(omap_rtc_alarm);
 485         else
 486                 rtc_write(irqstat, OMAP_RTC_INTERRUPTS_REG);
 487         return 0;
 488 }
 489
 490 #else
 491 #define omap_rtc_suspend NULL
 492 #define omap_rtc_resume  NULL
 493 #endif
 494
 495 static void omap_rtc_shutdown(struct platform_device *pdev)
 496 {
 497         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 498 }
 499
 500 MODULE_ALIAS("omap_rtc");
 501 static struct platform_driver omap_rtc_driver = {
 502         .probe          = omap_rtc_probe,
 503         .remove         = __devexit_p(omap_rtc_remove),
 504         .suspend        = omap_rtc_suspend,
 505         .resume         = omap_rtc_resume,
 506         .shutdown       = omap_rtc_shutdown,
 507         .driver         = {
 508                 .name   = "omap_rtc",
 509                 .owner  = THIS_MODULE,
 510         },
 511 };
 512
 513 static int __init rtc_init(void)
 514 {
 515         return platform_driver_register(&omap_rtc_driver);
 516 }
 517 module_init(rtc_init);
 518
 519 static void __exit rtc_exit(void)
 520 {
 521         platform_driver_unregister(&omap_rtc_driver);
 522 }
 523 module_exit(rtc_exit);
 524
 525 MODULE_AUTHOR("George G. Davis (and others)");
 526 MODULE_LICENSE("GPL");