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) for OMAP1 boards (OMAP-L138 has this built into
  38  * the SoC). 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 static void __iomem     *rtc_base;
  92
  93 #define rtc_read(addr)          __raw_readb(rtc_base + (addr))
  94 #define rtc_write(val, addr)    __raw_writeb(val, rtc_base + (addr))
  95
  96
  97 /* we rely on the rtc framework to handle locking (rtc->ops_lock),
  98  * so the only other requirement is that register accesses which
  99  * require BUSY to be clear are made with IRQs locally disabled
 100  */
 101 static void rtc_wait_not_busy(void)
 102 {
 103         int     count = 0;
 104         u8      status;
 105
 106         /* BUSY may stay active for 1/32768 second (~30 usec) */
 107         for (count = 0; count < 50; count++) {
 108                 status = rtc_read(OMAP_RTC_STATUS_REG);
 109                 if ((status & (u8)OMAP_RTC_STATUS_BUSY) == 0)
 110                         break;
 111                 udelay(1);
 112         }
 113         /* now we have ~15 usec to read/write various registers */
 114 }
 115
 116 static irqreturn_t rtc_irq(int irq, void *rtc)
 117 {
 118         unsigned long           events = 0;
 119         u8                      irq_data;
 120
 121         irq_data = rtc_read(OMAP_RTC_STATUS_REG);
 122
 123         /* alarm irq? */
 124         if (irq_data & OMAP_RTC_STATUS_ALARM) {
 125                 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
 126                 events |= RTC_IRQF | RTC_AF;
 127         }
 128
 129         /* 1/sec periodic/update irq? */
 130         if (irq_data & OMAP_RTC_STATUS_1S_EVENT)
 131                 events |= RTC_IRQF | RTC_UF;
 132
 133         rtc_update_irq(rtc, 1, events);
 134
 135         return IRQ_HANDLED;
 136 }
 137
 138 #ifdef  CONFIG_RTC_INTF_DEV
 139
 140 static int
 141 omap_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 142 {
 143         u8 reg;
 144
 145         switch (cmd) {
 146         case RTC_UIE_OFF:
 147         case RTC_UIE_ON:
 148                 break;
 149         default:
 150                 return -ENOIOCTLCMD;
 151         }
 152
 153         local_irq_disable();
 154         rtc_wait_not_busy();
 155         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 156         switch (cmd) {
 157         /* UIE = Update Interrupt Enable (1/second) */
 158         case RTC_UIE_OFF:
 159                 reg &= ~OMAP_RTC_INTERRUPTS_IT_TIMER;
 160                 break;
 161         case RTC_UIE_ON:
 162                 reg |= OMAP_RTC_INTERRUPTS_IT_TIMER;
 163                 break;
 164         }
 165         rtc_wait_not_busy();
 166         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 167         local_irq_enable();
 168
 169         return 0;
 170 }
 171
 172 #else
 173 #define omap_rtc_ioctl  NULL
 174 #endif
 175
 176 static int omap_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 177 {
 178         u8 reg;
 179
 180         local_irq_disable();
 181         rtc_wait_not_busy();
 182         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 183         if (enabled)
 184                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 185         else
 186                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 187         rtc_wait_not_busy();
 188         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 189         local_irq_enable();
 190
 191         return 0;
 192 }
 193
 194 /* this hardware doesn't support "don't care" alarm fields */
 195 static int tm2bcd(struct rtc_time *tm)
 196 {
 197         if (rtc_valid_tm(tm) != 0)
 198                 return -EINVAL;
 199
 200         tm->tm_sec = bin2bcd(tm->tm_sec);
 201         tm->tm_min = bin2bcd(tm->tm_min);
 202         tm->tm_hour = bin2bcd(tm->tm_hour);
 203         tm->tm_mday = bin2bcd(tm->tm_mday);
 204
 205         tm->tm_mon = bin2bcd(tm->tm_mon + 1);
 206
 207         /* epoch == 1900 */
 208         if (tm->tm_year < 100 || tm->tm_year > 199)
 209                 return -EINVAL;
 210         tm->tm_year = bin2bcd(tm->tm_year - 100);
 211
 212         return 0;
 213 }
 214
 215 static void bcd2tm(struct rtc_time *tm)
 216 {
 217         tm->tm_sec = bcd2bin(tm->tm_sec);
 218         tm->tm_min = bcd2bin(tm->tm_min);
 219         tm->tm_hour = bcd2bin(tm->tm_hour);
 220         tm->tm_mday = bcd2bin(tm->tm_mday);
 221         tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
 222         /* epoch == 1900 */
 223         tm->tm_year = bcd2bin(tm->tm_year) + 100;
 224 }
 225
 226
 227 static int omap_rtc_read_time(struct device *dev, struct rtc_time *tm)
 228 {
 229         /* we don't report wday/yday/isdst ... */
 230         local_irq_disable();
 231         rtc_wait_not_busy();
 232
 233         tm->tm_sec = rtc_read(OMAP_RTC_SECONDS_REG);
 234         tm->tm_min = rtc_read(OMAP_RTC_MINUTES_REG);
 235         tm->tm_hour = rtc_read(OMAP_RTC_HOURS_REG);
 236         tm->tm_mday = rtc_read(OMAP_RTC_DAYS_REG);
 237         tm->tm_mon = rtc_read(OMAP_RTC_MONTHS_REG);
 238         tm->tm_year = rtc_read(OMAP_RTC_YEARS_REG);
 239
 240         local_irq_enable();
 241
 242         bcd2tm(tm);
 243         return 0;
 244 }
 245
 246 static int omap_rtc_set_time(struct device *dev, struct rtc_time *tm)
 247 {
 248         if (tm2bcd(tm) < 0)
 249                 return -EINVAL;
 250         local_irq_disable();
 251         rtc_wait_not_busy();
 252
 253         rtc_write(tm->tm_year, OMAP_RTC_YEARS_REG);
 254         rtc_write(tm->tm_mon, OMAP_RTC_MONTHS_REG);
 255         rtc_write(tm->tm_mday, OMAP_RTC_DAYS_REG);
 256         rtc_write(tm->tm_hour, OMAP_RTC_HOURS_REG);
 257         rtc_write(tm->tm_min, OMAP_RTC_MINUTES_REG);
 258         rtc_write(tm->tm_sec, OMAP_RTC_SECONDS_REG);
 259
 260         local_irq_enable();
 261
 262         return 0;
 263 }
 264
 265 static int omap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 266 {
 267         local_irq_disable();
 268         rtc_wait_not_busy();
 269
 270         alm->time.tm_sec = rtc_read(OMAP_RTC_ALARM_SECONDS_REG);
 271         alm->time.tm_min = rtc_read(OMAP_RTC_ALARM_MINUTES_REG);
 272         alm->time.tm_hour = rtc_read(OMAP_RTC_ALARM_HOURS_REG);
 273         alm->time.tm_mday = rtc_read(OMAP_RTC_ALARM_DAYS_REG);
 274         alm->time.tm_mon = rtc_read(OMAP_RTC_ALARM_MONTHS_REG);
 275         alm->time.tm_year = rtc_read(OMAP_RTC_ALARM_YEARS_REG);
 276
 277         local_irq_enable();
 278
 279         bcd2tm(&alm->time);
 280         alm->enabled = !!(rtc_read(OMAP_RTC_INTERRUPTS_REG)
 281                         & OMAP_RTC_INTERRUPTS_IT_ALARM);
 282
 283         return 0;
 284 }
 285
 286 static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 287 {
 288         u8 reg;
 289
 290         if (tm2bcd(&alm->time) < 0)
 291                 return -EINVAL;
 292
 293         local_irq_disable();
 294         rtc_wait_not_busy();
 295
 296         rtc_write(alm->time.tm_year, OMAP_RTC_ALARM_YEARS_REG);
 297         rtc_write(alm->time.tm_mon, OMAP_RTC_ALARM_MONTHS_REG);
 298         rtc_write(alm->time.tm_mday, OMAP_RTC_ALARM_DAYS_REG);
 299         rtc_write(alm->time.tm_hour, OMAP_RTC_ALARM_HOURS_REG);
 300         rtc_write(alm->time.tm_min, OMAP_RTC_ALARM_MINUTES_REG);
 301         rtc_write(alm->time.tm_sec, OMAP_RTC_ALARM_SECONDS_REG);
 302
 303         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 304         if (alm->enabled)
 305                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 306         else
 307                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 308         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 309
 310         local_irq_enable();
 311
 312         return 0;
 313 }
 314
 315 static struct rtc_class_ops omap_rtc_ops = {
 316         .ioctl          = omap_rtc_ioctl,
 317         .read_time      = omap_rtc_read_time,
 318         .set_time       = omap_rtc_set_time,
 319         .read_alarm     = omap_rtc_read_alarm,
 320         .set_alarm      = omap_rtc_set_alarm,
 321         .alarm_irq_enable = omap_rtc_alarm_irq_enable,
 322 };
 323
 324 static int omap_rtc_alarm;
 325 static int omap_rtc_timer;
 326
 327 static int __init 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         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 346         if (!res) {
 347                 pr_debug("%s: RTC resource data missing\n", pdev->name);
 348                 return -ENOENT;
 349         }
 350
 351         mem = request_mem_region(res->start, resource_size(res), pdev->name);
 352         if (!mem) {
 353                 pr_debug("%s: RTC registers at %08x are not free\n",
 354                         pdev->name, res->start);
 355                 return -EBUSY;
 356         }
 357
 358         rtc_base = ioremap(res->start, resource_size(res));
 359         if (!rtc_base) {
 360                 pr_debug("%s: RTC registers can't be mapped\n", pdev->name);
 361                 goto fail;
 362         }
 363
 364         rtc = rtc_device_register(pdev->name, &pdev->dev,
 365                         &omap_rtc_ops, THIS_MODULE);
 366         if (IS_ERR(rtc)) {
 367                 pr_debug("%s: can't register RTC device, err %ld\n",
 368                         pdev->name, PTR_ERR(rtc));
 369                 goto fail0;
 370         }
 371         platform_set_drvdata(pdev, rtc);
 372         dev_set_drvdata(&rtc->dev, mem);
 373
 374         /* clear pending irqs, and set 1/second periodic,
 375          * which we'll use instead of update irqs
 376          */
 377         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 378
 379         /* clear old status */
 380         reg = rtc_read(OMAP_RTC_STATUS_REG);
 381         if (reg & (u8) OMAP_RTC_STATUS_POWER_UP) {
 382                 pr_info("%s: RTC power up reset detected\n",
 383                         pdev->name);
 384                 rtc_write(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG);
 385         }
 386         if (reg & (u8) OMAP_RTC_STATUS_ALARM)
 387                 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
 388
 389         /* handle periodic and alarm irqs */
 390         if (request_irq(omap_rtc_timer, rtc_irq, IRQF_DISABLED,
 391                         dev_name(&rtc->dev), rtc)) {
 392                 pr_debug("%s: RTC timer interrupt IRQ%d already claimed\n",
 393                         pdev->name, omap_rtc_timer);
 394                 goto fail1;
 395         }
 396         if ((omap_rtc_timer != omap_rtc_alarm) &&
 397                 (request_irq(omap_rtc_alarm, rtc_irq, IRQF_DISABLED,
 398                         dev_name(&rtc->dev), rtc))) {
 399                 pr_debug("%s: RTC alarm interrupt IRQ%d already claimed\n",
 400                         pdev->name, omap_rtc_alarm);
 401                 goto fail2;
 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          *  - Device wake-up capability setting should come through chip
 416          *    init logic. OMAP1 boards should initialize the "wakeup capable"
 417          *    flag in the platform device if the board is wired right for
 418          *    being woken up by RTC alarm. For OMAP-L138, this capability
 419          *    is built into the SoC by the "Deep Sleep" capability.
 420          *
 421          *  - Boards wired so RTC_ON_nOFF is used as the reset signal,
 422          *    rather than nPWRON_RESET, should forcibly enable split
 423          *    power mode.  (Some chip errata report that RTC_CTRL_SPLIT
 424          *    is write-only, and always reads as zero...)
 425          */
 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 fail2:
 436         free_irq(omap_rtc_timer, NULL);
 437 fail1:
 438         rtc_device_unregister(rtc);
 439 fail0:
 440         iounmap(rtc_base);
 441 fail:
 442         release_mem_region(mem->start, resource_size(mem));
 443         return -EIO;
 444 }
 445
 446 static int __exit omap_rtc_remove(struct platform_device *pdev)
 447 {
 448         struct rtc_device       *rtc = platform_get_drvdata(pdev);
 449         struct resource         *mem = dev_get_drvdata(&rtc->dev);
 450
 451         device_init_wakeup(&pdev->dev, 0);
 452
 453         /* leave rtc running, but disable irqs */
 454         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 455
 456         free_irq(omap_rtc_timer, rtc);
 457
 458         if (omap_rtc_timer != omap_rtc_alarm)
 459                 free_irq(omap_rtc_alarm, rtc);
 460
 461         rtc_device_unregister(rtc);
 462         iounmap(rtc_base);
 463         release_mem_region(mem->start, resource_size(mem));
 464         return 0;
 465 }
 466
 467 #ifdef CONFIG_PM
 468
 469 static u8 irqstat;
 470
 471 static int omap_rtc_suspend(struct platform_device *pdev, pm_message_t state)
 472 {
 473         irqstat = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 474
 475         /* FIXME the RTC alarm is not currently acting as a wakeup event
 476          * source, and in fact this enable() call is just saving a flag
 477          * that's never used...
 478          */
 479         if (device_may_wakeup(&pdev->dev))
 480                 enable_irq_wake(omap_rtc_alarm);
 481         else
 482                 rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 483
 484         return 0;
 485 }
 486
 487 static int omap_rtc_resume(struct platform_device *pdev)
 488 {
 489         if (device_may_wakeup(&pdev->dev))
 490                 disable_irq_wake(omap_rtc_alarm);
 491         else
 492                 rtc_write(irqstat, OMAP_RTC_INTERRUPTS_REG);
 493         return 0;
 494 }
 495
 496 #else
 497 #define omap_rtc_suspend NULL
 498 #define omap_rtc_resume  NULL
 499 #endif
 500
 501 static void omap_rtc_shutdown(struct platform_device *pdev)
 502 {
 503         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 504 }
 505
 506 MODULE_ALIAS("platform:omap_rtc");
 507 static struct platform_driver omap_rtc_driver = {
 508         .remove         = __exit_p(omap_rtc_remove),
 509         .suspend        = omap_rtc_suspend,
 510         .resume         = omap_rtc_resume,
 511         .shutdown       = omap_rtc_shutdown,
 512         .driver         = {
 513                 .name   = "omap_rtc",
 514                 .owner  = THIS_MODULE,
 515         },
 516 };
 517
 518 static int __init rtc_init(void)
 519 {
 520         return platform_driver_probe(&omap_rtc_driver, omap_rtc_probe);
 521 }
 522 module_init(rtc_init);
 523
 524 static void __exit rtc_exit(void)
 525 {
 526         platform_driver_unregister(&omap_rtc_driver);
 527 }
 528 module_exit(rtc_exit);
 529
 530 MODULE_AUTHOR("George G. Davis (and others)");
 531 MODULE_LICENSE("GPL");