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