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 #include <linux/of.h>
  24 #include <linux/of_device.h>
  25 #include <linux/pm_runtime.h>
  26 #include <linux/io.h>
  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) for OMAP1 boards (OMAP-L138 has this built into
  39  * the SoC). See the BOARD-SPECIFIC CUSTOMIZATION comment.
  40  */
  41
  42 #define DRIVER_NAME                     "omap_rtc"
  43
  44 #define OMAP_RTC_BASE                   0xfffb4800
  45
  46 /* RTC registers */
  47 #define OMAP_RTC_SECONDS_REG            0x00
  48 #define OMAP_RTC_MINUTES_REG            0x04
  49 #define OMAP_RTC_HOURS_REG              0x08
  50 #define OMAP_RTC_DAYS_REG               0x0C
  51 #define OMAP_RTC_MONTHS_REG             0x10
  52 #define OMAP_RTC_YEARS_REG              0x14
  53 #define OMAP_RTC_WEEKS_REG              0x18
  54
  55 #define OMAP_RTC_ALARM_SECONDS_REG      0x20
  56 #define OMAP_RTC_ALARM_MINUTES_REG      0x24
  57 #define OMAP_RTC_ALARM_HOURS_REG        0x28
  58 #define OMAP_RTC_ALARM_DAYS_REG         0x2c
  59 #define OMAP_RTC_ALARM_MONTHS_REG       0x30
  60 #define OMAP_RTC_ALARM_YEARS_REG        0x34
  61
  62 #define OMAP_RTC_CTRL_REG               0x40
  63 #define OMAP_RTC_STATUS_REG             0x44
  64 #define OMAP_RTC_INTERRUPTS_REG         0x48
  65
  66 #define OMAP_RTC_COMP_LSB_REG           0x4c
  67 #define OMAP_RTC_COMP_MSB_REG           0x50
  68 #define OMAP_RTC_OSC_REG                0x54
  69
  70 #define OMAP_RTC_KICK0_REG              0x6c
  71 #define OMAP_RTC_KICK1_REG              0x70
  72
  73 /* OMAP_RTC_CTRL_REG bit fields: */
  74 #define OMAP_RTC_CTRL_SPLIT             (1<<7)
  75 #define OMAP_RTC_CTRL_DISABLE           (1<<6)
  76 #define OMAP_RTC_CTRL_SET_32_COUNTER    (1<<5)
  77 #define OMAP_RTC_CTRL_TEST              (1<<4)
  78 #define OMAP_RTC_CTRL_MODE_12_24        (1<<3)
  79 #define OMAP_RTC_CTRL_AUTO_COMP         (1<<2)
  80 #define OMAP_RTC_CTRL_ROUND_30S         (1<<1)
  81 #define OMAP_RTC_CTRL_STOP              (1<<0)
  82
  83 /* OMAP_RTC_STATUS_REG bit fields: */
  84 #define OMAP_RTC_STATUS_POWER_UP        (1<<7)
  85 #define OMAP_RTC_STATUS_ALARM           (1<<6)
  86 #define OMAP_RTC_STATUS_1D_EVENT        (1<<5)
  87 #define OMAP_RTC_STATUS_1H_EVENT        (1<<4)
  88 #define OMAP_RTC_STATUS_1M_EVENT        (1<<3)
  89 #define OMAP_RTC_STATUS_1S_EVENT        (1<<2)
  90 #define OMAP_RTC_STATUS_RUN             (1<<1)
  91 #define OMAP_RTC_STATUS_BUSY            (1<<0)
  92
  93 /* OMAP_RTC_INTERRUPTS_REG bit fields: */
  94 #define OMAP_RTC_INTERRUPTS_IT_ALARM    (1<<3)
  95 #define OMAP_RTC_INTERRUPTS_IT_TIMER    (1<<2)
  96
  97 /* OMAP_RTC_KICKER values */
  98 #define KICK0_VALUE                     0x83e70b13
  99 #define KICK1_VALUE                     0x95a4f1e0
 100
 101 #define OMAP_RTC_HAS_KICKER             0x1
 102
 103 static void __iomem     *rtc_base;
 104
 105 #define rtc_read(addr)          readb(rtc_base + (addr))
 106 #define rtc_write(val, addr)    writeb(val, rtc_base + (addr))
 107
 108 #define rtc_writel(val, addr)   writel(val, rtc_base + (addr))
 109
 110
 111 /* we rely on the rtc framework to handle locking (rtc->ops_lock),
 112  * so the only other requirement is that register accesses which
 113  * require BUSY to be clear are made with IRQs locally disabled
 114  */
 115 static void rtc_wait_not_busy(void)
 116 {
 117         int     count = 0;
 118         u8      status;
 119
 120         /* BUSY may stay active for 1/32768 second (~30 usec) */
 121         for (count = 0; count < 50; count++) {
 122                 status = rtc_read(OMAP_RTC_STATUS_REG);
 123                 if ((status & (u8)OMAP_RTC_STATUS_BUSY) == 0)
 124                         break;
 125                 udelay(1);
 126         }
 127         /* now we have ~15 usec to read/write various registers */
 128 }
 129
 130 static irqreturn_t rtc_irq(int irq, void *rtc)
 131 {
 132         unsigned long           events = 0;
 133         u8                      irq_data;
 134
 135         irq_data = rtc_read(OMAP_RTC_STATUS_REG);
 136
 137         /* alarm irq? */
 138         if (irq_data & OMAP_RTC_STATUS_ALARM) {
 139                 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
 140                 events |= RTC_IRQF | RTC_AF;
 141         }
 142
 143         /* 1/sec periodic/update irq? */
 144         if (irq_data & OMAP_RTC_STATUS_1S_EVENT)
 145                 events |= RTC_IRQF | RTC_UF;
 146
 147         rtc_update_irq(rtc, 1, events);
 148
 149         return IRQ_HANDLED;
 150 }
 151
 152 static int omap_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 153 {
 154         u8 reg;
 155
 156         local_irq_disable();
 157         rtc_wait_not_busy();
 158         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 159         if (enabled)
 160                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 161         else
 162                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 163         rtc_wait_not_busy();
 164         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 165         local_irq_enable();
 166
 167         return 0;
 168 }
 169
 170 /* this hardware doesn't support "don't care" alarm fields */
 171 static int tm2bcd(struct rtc_time *tm)
 172 {
 173         if (rtc_valid_tm(tm) != 0)
 174                 return -EINVAL;
 175
 176         tm->tm_sec = bin2bcd(tm->tm_sec);
 177         tm->tm_min = bin2bcd(tm->tm_min);
 178         tm->tm_hour = bin2bcd(tm->tm_hour);
 179         tm->tm_mday = bin2bcd(tm->tm_mday);
 180
 181         tm->tm_mon = bin2bcd(tm->tm_mon + 1);
 182
 183         /* epoch == 1900 */
 184         if (tm->tm_year < 100 || tm->tm_year > 199)
 185                 return -EINVAL;
 186         tm->tm_year = bin2bcd(tm->tm_year - 100);
 187
 188         return 0;
 189 }
 190
 191 static void bcd2tm(struct rtc_time *tm)
 192 {
 193         tm->tm_sec = bcd2bin(tm->tm_sec);
 194         tm->tm_min = bcd2bin(tm->tm_min);
 195         tm->tm_hour = bcd2bin(tm->tm_hour);
 196         tm->tm_mday = bcd2bin(tm->tm_mday);
 197         tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
 198         /* epoch == 1900 */
 199         tm->tm_year = bcd2bin(tm->tm_year) + 100;
 200 }
 201
 202
 203 static int omap_rtc_read_time(struct device *dev, struct rtc_time *tm)
 204 {
 205         /* we don't report wday/yday/isdst ... */
 206         local_irq_disable();
 207         rtc_wait_not_busy();
 208
 209         tm->tm_sec = rtc_read(OMAP_RTC_SECONDS_REG);
 210         tm->tm_min = rtc_read(OMAP_RTC_MINUTES_REG);
 211         tm->tm_hour = rtc_read(OMAP_RTC_HOURS_REG);
 212         tm->tm_mday = rtc_read(OMAP_RTC_DAYS_REG);
 213         tm->tm_mon = rtc_read(OMAP_RTC_MONTHS_REG);
 214         tm->tm_year = rtc_read(OMAP_RTC_YEARS_REG);
 215
 216         local_irq_enable();
 217
 218         bcd2tm(tm);
 219         return 0;
 220 }
 221
 222 static int omap_rtc_set_time(struct device *dev, struct rtc_time *tm)
 223 {
 224         if (tm2bcd(tm) < 0)
 225                 return -EINVAL;
 226         local_irq_disable();
 227         rtc_wait_not_busy();
 228
 229         rtc_write(tm->tm_year, OMAP_RTC_YEARS_REG);
 230         rtc_write(tm->tm_mon, OMAP_RTC_MONTHS_REG);
 231         rtc_write(tm->tm_mday, OMAP_RTC_DAYS_REG);
 232         rtc_write(tm->tm_hour, OMAP_RTC_HOURS_REG);
 233         rtc_write(tm->tm_min, OMAP_RTC_MINUTES_REG);
 234         rtc_write(tm->tm_sec, OMAP_RTC_SECONDS_REG);
 235
 236         local_irq_enable();
 237
 238         return 0;
 239 }
 240
 241 static int omap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 242 {
 243         local_irq_disable();
 244         rtc_wait_not_busy();
 245
 246         alm->time.tm_sec = rtc_read(OMAP_RTC_ALARM_SECONDS_REG);
 247         alm->time.tm_min = rtc_read(OMAP_RTC_ALARM_MINUTES_REG);
 248         alm->time.tm_hour = rtc_read(OMAP_RTC_ALARM_HOURS_REG);
 249         alm->time.tm_mday = rtc_read(OMAP_RTC_ALARM_DAYS_REG);
 250         alm->time.tm_mon = rtc_read(OMAP_RTC_ALARM_MONTHS_REG);
 251         alm->time.tm_year = rtc_read(OMAP_RTC_ALARM_YEARS_REG);
 252
 253         local_irq_enable();
 254
 255         bcd2tm(&alm->time);
 256         alm->enabled = !!(rtc_read(OMAP_RTC_INTERRUPTS_REG)
 257                         & OMAP_RTC_INTERRUPTS_IT_ALARM);
 258
 259         return 0;
 260 }
 261
 262 static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 263 {
 264         u8 reg;
 265
 266         if (tm2bcd(&alm->time) < 0)
 267                 return -EINVAL;
 268
 269         local_irq_disable();
 270         rtc_wait_not_busy();
 271
 272         rtc_write(alm->time.tm_year, OMAP_RTC_ALARM_YEARS_REG);
 273         rtc_write(alm->time.tm_mon, OMAP_RTC_ALARM_MONTHS_REG);
 274         rtc_write(alm->time.tm_mday, OMAP_RTC_ALARM_DAYS_REG);
 275         rtc_write(alm->time.tm_hour, OMAP_RTC_ALARM_HOURS_REG);
 276         rtc_write(alm->time.tm_min, OMAP_RTC_ALARM_MINUTES_REG);
 277         rtc_write(alm->time.tm_sec, OMAP_RTC_ALARM_SECONDS_REG);
 278
 279         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 280         if (alm->enabled)
 281                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 282         else
 283                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 284         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 285
 286         local_irq_enable();
 287
 288         return 0;
 289 }
 290
 291 static struct rtc_class_ops omap_rtc_ops = {
 292         .read_time      = omap_rtc_read_time,
 293         .set_time       = omap_rtc_set_time,
 294         .read_alarm     = omap_rtc_read_alarm,
 295         .set_alarm      = omap_rtc_set_alarm,
 296         .alarm_irq_enable = omap_rtc_alarm_irq_enable,
 297 };
 298
 299 static int omap_rtc_alarm;
 300 static int omap_rtc_timer;
 301
 302 #define OMAP_RTC_DATA_DA830_IDX 1
 303
 304 static struct platform_device_id omap_rtc_devtype[] = {
 305         {
 306                 .name   = DRIVER_NAME,
 307         }, {
 308                 .name   = "da830-rtc",
 309                 .driver_data = OMAP_RTC_HAS_KICKER,
 310         },
 311         {},
 312 };
 313 MODULE_DEVICE_TABLE(platform, omap_rtc_devtype);
 314
 315 static const struct of_device_id omap_rtc_of_match[] = {
 316         {       .compatible     = "ti,da830-rtc",
 317                 .data           = &omap_rtc_devtype[OMAP_RTC_DATA_DA830_IDX],
 318         },
 319         {},
 320 };
 321 MODULE_DEVICE_TABLE(of, omap_rtc_of_match);
 322
 323 static int __init omap_rtc_probe(struct platform_device *pdev)
 324 {
 325         struct resource         *res;
 326         struct rtc_device       *rtc;
 327         u8                      reg, new_ctrl;
 328         const struct platform_device_id *id_entry;
 329         const struct of_device_id *of_id;
 330
 331         of_id = of_match_device(omap_rtc_of_match, &pdev->dev);
 332         if (of_id)
 333                 pdev->id_entry = of_id->data;
 334
 335         omap_rtc_timer = platform_get_irq(pdev, 0);
 336         if (omap_rtc_timer <= 0) {
 337                 pr_debug("%s: no update irq?\n", pdev->name);
 338                 return -ENOENT;
 339         }
 340
 341         omap_rtc_alarm = platform_get_irq(pdev, 1);
 342         if (omap_rtc_alarm <= 0) {
 343                 pr_debug("%s: no alarm irq?\n", pdev->name);
 344                 return -ENOENT;
 345         }
 346
 347         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 348         rtc_base = devm_ioremap_resource(&pdev->dev, res);
 349         if (IS_ERR(rtc_base))
 350                 return PTR_ERR(rtc_base);
 351
 352         /* Enable the clock/module so that we can access the registers */
 353         pm_runtime_enable(&pdev->dev);
 354         pm_runtime_get_sync(&pdev->dev);
 355
 356         id_entry = platform_get_device_id(pdev);
 357         if (id_entry && (id_entry->driver_data & OMAP_RTC_HAS_KICKER)) {
 358                 rtc_writel(KICK0_VALUE, OMAP_RTC_KICK0_REG);
 359                 rtc_writel(KICK1_VALUE, OMAP_RTC_KICK1_REG);
 360         }
 361
 362         rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 363                         &omap_rtc_ops, THIS_MODULE);
 364         if (IS_ERR(rtc)) {
 365                 pr_debug("%s: can't register RTC device, err %ld\n",
 366                         pdev->name, PTR_ERR(rtc));
 367                 goto fail0;
 368         }
 369         platform_set_drvdata(pdev, rtc);
 370
 371         /* clear pending irqs, and set 1/second periodic,
 372          * which we'll use instead of update irqs
 373          */
 374         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 375
 376         /* clear old status */
 377         reg = rtc_read(OMAP_RTC_STATUS_REG);
 378         if (reg & (u8) OMAP_RTC_STATUS_POWER_UP) {
 379                 pr_info("%s: RTC power up reset detected\n",
 380                         pdev->name);
 381                 rtc_write(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG);
 382         }
 383         if (reg & (u8) OMAP_RTC_STATUS_ALARM)
 384                 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
 385
 386         /* handle periodic and alarm irqs */
 387         if (devm_request_irq(&pdev->dev, omap_rtc_timer, rtc_irq, 0,
 388                         dev_name(&rtc->dev), rtc)) {
 389                 pr_debug("%s: RTC timer interrupt IRQ%d already claimed\n",
 390                         pdev->name, omap_rtc_timer);
 391                 goto fail0;
 392         }
 393         if ((omap_rtc_timer != omap_rtc_alarm) &&
 394                 (devm_request_irq(&pdev->dev, omap_rtc_alarm, rtc_irq, 0,
 395                         dev_name(&rtc->dev), rtc))) {
 396                 pr_debug("%s: RTC alarm interrupt IRQ%d already claimed\n",
 397                         pdev->name, omap_rtc_alarm);
 398                 goto fail0;
 399         }
 400
 401         /* On boards with split power, RTC_ON_NOFF won't reset the RTC */
 402         reg = rtc_read(OMAP_RTC_CTRL_REG);
 403         if (reg & (u8) OMAP_RTC_CTRL_STOP)
 404                 pr_info("%s: already running\n", pdev->name);
 405
 406         /* force to 24 hour mode */
 407         new_ctrl = reg & (OMAP_RTC_CTRL_SPLIT|OMAP_RTC_CTRL_AUTO_COMP);
 408         new_ctrl |= OMAP_RTC_CTRL_STOP;
 409
 410         /* BOARD-SPECIFIC CUSTOMIZATION CAN GO HERE:
 411          *
 412          *  - Device wake-up capability setting should come through chip
 413          *    init logic. OMAP1 boards should initialize the "wakeup capable"
 414          *    flag in the platform device if the board is wired right for
 415          *    being woken up by RTC alarm. For OMAP-L138, this capability
 416          *    is built into the SoC by the "Deep Sleep" capability.
 417          *
 418          *  - Boards wired so RTC_ON_nOFF is used as the reset signal,
 419          *    rather than nPWRON_RESET, should forcibly enable split
 420          *    power mode.  (Some chip errata report that RTC_CTRL_SPLIT
 421          *    is write-only, and always reads as zero...)
 422          */
 423
 424         device_init_wakeup(&pdev->dev, true);
 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 fail0:
 435         if (id_entry && (id_entry->driver_data & OMAP_RTC_HAS_KICKER))
 436                 rtc_writel(0, OMAP_RTC_KICK0_REG);
 437         pm_runtime_put_sync(&pdev->dev);
 438         pm_runtime_disable(&pdev->dev);
 439         return -EIO;
 440 }
 441
 442 static int __exit omap_rtc_remove(struct platform_device *pdev)
 443 {
 444         const struct platform_device_id *id_entry =
 445                                 platform_get_device_id(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         if (id_entry && (id_entry->driver_data & OMAP_RTC_HAS_KICKER))
 453                 rtc_writel(0, OMAP_RTC_KICK0_REG);
 454
 455         /* Disable the clock/module */
 456         pm_runtime_put_sync(&pdev->dev);
 457         pm_runtime_disable(&pdev->dev);
 458
 459         return 0;
 460 }
 461
 462 #ifdef CONFIG_PM_SLEEP
 463 static u8 irqstat;
 464
 465 static int omap_rtc_suspend(struct device *dev)
 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(dev))
 474                 enable_irq_wake(omap_rtc_alarm);
 475         else
 476                 rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 477
 478         /* Disable the clock/module */
 479         pm_runtime_put_sync(dev);
 480
 481         return 0;
 482 }
 483
 484 static int omap_rtc_resume(struct device *dev)
 485 {
 486         /* Enable the clock/module so that we can access the registers */
 487         pm_runtime_get_sync(dev);
 488
 489         if (device_may_wakeup(dev))
 490                 disable_irq_wake(omap_rtc_alarm);
 491         else
 492                 rtc_write(irqstat, OMAP_RTC_INTERRUPTS_REG);
 493         return 0;
 494 }
 495 #endif
 496
 497 static SIMPLE_DEV_PM_OPS(omap_rtc_pm_ops, omap_rtc_suspend, omap_rtc_resume);
 498
 499 static void omap_rtc_shutdown(struct platform_device *pdev)
 500 {
 501         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 502 }
 503
 504 MODULE_ALIAS("platform:omap_rtc");
 505 static struct platform_driver omap_rtc_driver = {
 506         .remove         = __exit_p(omap_rtc_remove),
 507         .shutdown       = omap_rtc_shutdown,
 508         .driver         = {
 509                 .name   = DRIVER_NAME,
 510                 .owner  = THIS_MODULE,
 511                 .pm     = &omap_rtc_pm_ops,
 512                 .of_match_table = of_match_ptr(omap_rtc_of_match),
 513         },
 514         .id_table       = omap_rtc_devtype,
 515 };
 516
 517 module_platform_driver_probe(omap_rtc_driver, omap_rtc_probe);
 518
 519 MODULE_AUTHOR("George G. Davis (and others)");
 520 MODULE_LICENSE("GPL");