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_AIE_OFF:
 147         case RTC_AIE_ON:
 148         case RTC_UIE_OFF:
 149         case RTC_UIE_ON:
 150                 break;
 151         default:
 152                 return -ENOIOCTLCMD;
 153         }
 154
 155         local_irq_disable();
 156         rtc_wait_not_busy();
 157         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 158         switch (cmd) {
 159         /* AIE = Alarm Interrupt Enable */
 160         case RTC_AIE_OFF:
 161                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 162                 break;
 163         case RTC_AIE_ON:
 164                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 165                 break;
 166         /* UIE = Update Interrupt Enable (1/second) */
 167         case RTC_UIE_OFF:
 168                 reg &= ~OMAP_RTC_INTERRUPTS_IT_TIMER;
 169                 break;
 170         case RTC_UIE_ON:
 171                 reg |= OMAP_RTC_INTERRUPTS_IT_TIMER;
 172                 break;
 173         }
 174         rtc_wait_not_busy();
 175         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 176         local_irq_enable();
 177
 178         return 0;
 179 }
 180
 181 #else
 182 #define omap_rtc_ioctl  NULL
 183 #endif
 184
 185 /* this hardware doesn't support "don't care" alarm fields */
 186 static int tm2bcd(struct rtc_time *tm)
 187 {
 188         if (rtc_valid_tm(tm) != 0)
 189                 return -EINVAL;
 190
 191         tm->tm_sec = bin2bcd(tm->tm_sec);
 192         tm->tm_min = bin2bcd(tm->tm_min);
 193         tm->tm_hour = bin2bcd(tm->tm_hour);
 194         tm->tm_mday = bin2bcd(tm->tm_mday);
 195
 196         tm->tm_mon = bin2bcd(tm->tm_mon + 1);
 197
 198         /* epoch == 1900 */
 199         if (tm->tm_year < 100 || tm->tm_year > 199)
 200                 return -EINVAL;
 201         tm->tm_year = bin2bcd(tm->tm_year - 100);
 202
 203         return 0;
 204 }
 205
 206 static void bcd2tm(struct rtc_time *tm)
 207 {
 208         tm->tm_sec = bcd2bin(tm->tm_sec);
 209         tm->tm_min = bcd2bin(tm->tm_min);
 210         tm->tm_hour = bcd2bin(tm->tm_hour);
 211         tm->tm_mday = bcd2bin(tm->tm_mday);
 212         tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
 213         /* epoch == 1900 */
 214         tm->tm_year = bcd2bin(tm->tm_year) + 100;
 215 }
 216
 217
 218 static int omap_rtc_read_time(struct device *dev, struct rtc_time *tm)
 219 {
 220         /* we don't report wday/yday/isdst ... */
 221         local_irq_disable();
 222         rtc_wait_not_busy();
 223
 224         tm->tm_sec = rtc_read(OMAP_RTC_SECONDS_REG);
 225         tm->tm_min = rtc_read(OMAP_RTC_MINUTES_REG);
 226         tm->tm_hour = rtc_read(OMAP_RTC_HOURS_REG);
 227         tm->tm_mday = rtc_read(OMAP_RTC_DAYS_REG);
 228         tm->tm_mon = rtc_read(OMAP_RTC_MONTHS_REG);
 229         tm->tm_year = rtc_read(OMAP_RTC_YEARS_REG);
 230
 231         local_irq_enable();
 232
 233         bcd2tm(tm);
 234         return 0;
 235 }
 236
 237 static int omap_rtc_set_time(struct device *dev, struct rtc_time *tm)
 238 {
 239         if (tm2bcd(tm) < 0)
 240                 return -EINVAL;
 241         local_irq_disable();
 242         rtc_wait_not_busy();
 243
 244         rtc_write(tm->tm_year, OMAP_RTC_YEARS_REG);
 245         rtc_write(tm->tm_mon, OMAP_RTC_MONTHS_REG);
 246         rtc_write(tm->tm_mday, OMAP_RTC_DAYS_REG);
 247         rtc_write(tm->tm_hour, OMAP_RTC_HOURS_REG);
 248         rtc_write(tm->tm_min, OMAP_RTC_MINUTES_REG);
 249         rtc_write(tm->tm_sec, OMAP_RTC_SECONDS_REG);
 250
 251         local_irq_enable();
 252
 253         return 0;
 254 }
 255
 256 static int omap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 257 {
 258         local_irq_disable();
 259         rtc_wait_not_busy();
 260
 261         alm->time.tm_sec = rtc_read(OMAP_RTC_ALARM_SECONDS_REG);
 262         alm->time.tm_min = rtc_read(OMAP_RTC_ALARM_MINUTES_REG);
 263         alm->time.tm_hour = rtc_read(OMAP_RTC_ALARM_HOURS_REG);
 264         alm->time.tm_mday = rtc_read(OMAP_RTC_ALARM_DAYS_REG);
 265         alm->time.tm_mon = rtc_read(OMAP_RTC_ALARM_MONTHS_REG);
 266         alm->time.tm_year = rtc_read(OMAP_RTC_ALARM_YEARS_REG);
 267
 268         local_irq_enable();
 269
 270         bcd2tm(&alm->time);
 271         alm->enabled = !!(rtc_read(OMAP_RTC_INTERRUPTS_REG)
 272                         & OMAP_RTC_INTERRUPTS_IT_ALARM);
 273
 274         return 0;
 275 }
 276
 277 static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 278 {
 279         u8 reg;
 280
 281         if (tm2bcd(&alm->time) < 0)
 282                 return -EINVAL;
 283
 284         local_irq_disable();
 285         rtc_wait_not_busy();
 286
 287         rtc_write(alm->time.tm_year, OMAP_RTC_ALARM_YEARS_REG);
 288         rtc_write(alm->time.tm_mon, OMAP_RTC_ALARM_MONTHS_REG);
 289         rtc_write(alm->time.tm_mday, OMAP_RTC_ALARM_DAYS_REG);
 290         rtc_write(alm->time.tm_hour, OMAP_RTC_ALARM_HOURS_REG);
 291         rtc_write(alm->time.tm_min, OMAP_RTC_ALARM_MINUTES_REG);
 292         rtc_write(alm->time.tm_sec, OMAP_RTC_ALARM_SECONDS_REG);
 293
 294         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 295         if (alm->enabled)
 296                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 297         else
 298                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 299         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 300
 301         local_irq_enable();
 302
 303         return 0;
 304 }
 305
 306 static struct rtc_class_ops omap_rtc_ops = {
 307         .ioctl          = omap_rtc_ioctl,
 308         .read_time      = omap_rtc_read_time,
 309         .set_time       = omap_rtc_set_time,
 310         .read_alarm     = omap_rtc_read_alarm,
 311         .set_alarm      = omap_rtc_set_alarm,
 312 };
 313
 314 static int omap_rtc_alarm;
 315 static int omap_rtc_timer;
 316
 317 static int __init omap_rtc_probe(struct platform_device *pdev)
 318 {
 319         struct resource         *res, *mem;
 320         struct rtc_device       *rtc;
 321         u8                      reg, new_ctrl;
 322
 323         omap_rtc_timer = platform_get_irq(pdev, 0);
 324         if (omap_rtc_timer <= 0) {
 325                 pr_debug("%s: no update irq?\n", pdev->name);
 326                 return -ENOENT;
 327         }
 328
 329         omap_rtc_alarm = platform_get_irq(pdev, 1);
 330         if (omap_rtc_alarm <= 0) {
 331                 pr_debug("%s: no alarm irq?\n", pdev->name);
 332                 return -ENOENT;
 333         }
 334
 335         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 336         if (!res) {
 337                 pr_debug("%s: RTC resource data missing\n", pdev->name);
 338                 return -ENOENT;
 339         }
 340
 341         mem = request_mem_region(res->start, resource_size(res), pdev->name);
 342         if (!mem) {
 343                 pr_debug("%s: RTC registers at %08x are not free\n",
 344                         pdev->name, res->start);
 345                 return -EBUSY;
 346         }
 347
 348         rtc_base = ioremap(res->start, resource_size(res));
 349         if (!rtc_base) {
 350                 pr_debug("%s: RTC registers can't be mapped\n", pdev->name);
 351                 goto fail;
 352         }
 353
 354         rtc = rtc_device_register(pdev->name, &pdev->dev,
 355                         &omap_rtc_ops, THIS_MODULE);
 356         if (IS_ERR(rtc)) {
 357                 pr_debug("%s: can't register RTC device, err %ld\n",
 358                         pdev->name, PTR_ERR(rtc));
 359                 goto fail0;
 360         }
 361         platform_set_drvdata(pdev, rtc);
 362         dev_set_drvdata(&rtc->dev, mem);
 363
 364         /* clear pending irqs, and set 1/second periodic,
 365          * which we'll use instead of update irqs
 366          */
 367         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 368
 369         /* clear old status */
 370         reg = rtc_read(OMAP_RTC_STATUS_REG);
 371         if (reg & (u8) OMAP_RTC_STATUS_POWER_UP) {
 372                 pr_info("%s: RTC power up reset detected\n",
 373                         pdev->name);
 374                 rtc_write(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG);
 375         }
 376         if (reg & (u8) OMAP_RTC_STATUS_ALARM)
 377                 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
 378
 379         /* handle periodic and alarm irqs */
 380         if (request_irq(omap_rtc_timer, rtc_irq, IRQF_DISABLED,
 381                         dev_name(&rtc->dev), rtc)) {
 382                 pr_debug("%s: RTC timer interrupt IRQ%d already claimed\n",
 383                         pdev->name, omap_rtc_timer);
 384                 goto fail1;
 385         }
 386         if ((omap_rtc_timer != omap_rtc_alarm) &&
 387                 (request_irq(omap_rtc_alarm, rtc_irq, IRQF_DISABLED,
 388                         dev_name(&rtc->dev), rtc))) {
 389                 pr_debug("%s: RTC alarm interrupt IRQ%d already claimed\n",
 390                         pdev->name, omap_rtc_alarm);
 391                 goto fail2;
 392         }
 393
 394         /* On boards with split power, RTC_ON_NOFF won't reset the RTC */
 395         reg = rtc_read(OMAP_RTC_CTRL_REG);
 396         if (reg & (u8) OMAP_RTC_CTRL_STOP)
 397                 pr_info("%s: already running\n", pdev->name);
 398
 399         /* force to 24 hour mode */
 400         new_ctrl = reg & ~(OMAP_RTC_CTRL_SPLIT|OMAP_RTC_CTRL_AUTO_COMP);
 401         new_ctrl |= OMAP_RTC_CTRL_STOP;
 402
 403         /* BOARD-SPECIFIC CUSTOMIZATION CAN GO HERE:
 404          *
 405          *  - Device wake-up capability setting should come through chip
 406          *    init logic. OMAP1 boards should initialize the "wakeup capable"
 407          *    flag in the platform device if the board is wired right for
 408          *    being woken up by RTC alarm. For OMAP-L138, this capability
 409          *    is built into the SoC by the "Deep Sleep" capability.
 410          *
 411          *  - Boards wired so RTC_ON_nOFF is used as the reset signal,
 412          *    rather than nPWRON_RESET, should forcibly enable split
 413          *    power mode.  (Some chip errata report that RTC_CTRL_SPLIT
 414          *    is write-only, and always reads as zero...)
 415          */
 416
 417         if (new_ctrl & (u8) OMAP_RTC_CTRL_SPLIT)
 418                 pr_info("%s: split power mode\n", pdev->name);
 419
 420         if (reg != new_ctrl)
 421                 rtc_write(new_ctrl, OMAP_RTC_CTRL_REG);
 422
 423         return 0;
 424
 425 fail2:
 426         free_irq(omap_rtc_timer, NULL);
 427 fail1:
 428         rtc_device_unregister(rtc);
 429 fail0:
 430         iounmap(rtc_base);
 431 fail:
 432         release_mem_region(mem->start, resource_size(mem));
 433         return -EIO;
 434 }
 435
 436 static int __exit omap_rtc_remove(struct platform_device *pdev)
 437 {
 438         struct rtc_device       *rtc = platform_get_drvdata(pdev);
 439         struct resource         *mem = dev_get_drvdata(&rtc->dev);
 440
 441         device_init_wakeup(&pdev->dev, 0);
 442
 443         /* leave rtc running, but disable irqs */
 444         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 445
 446         free_irq(omap_rtc_timer, rtc);
 447
 448         if (omap_rtc_timer != omap_rtc_alarm)
 449                 free_irq(omap_rtc_alarm, rtc);
 450
 451         rtc_device_unregister(rtc);
 452         iounmap(rtc_base);
 453         release_mem_region(mem->start, resource_size(mem));
 454         return 0;
 455 }
 456
 457 #ifdef CONFIG_PM
 458
 459 static u8 irqstat;
 460
 461 static int omap_rtc_suspend(struct platform_device *pdev, pm_message_t state)
 462 {
 463         irqstat = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 464
 465         /* FIXME the RTC alarm is not currently acting as a wakeup event
 466          * source, and in fact this enable() call is just saving a flag
 467          * that's never used...
 468          */
 469         if (device_may_wakeup(&pdev->dev))
 470                 enable_irq_wake(omap_rtc_alarm);
 471         else
 472                 rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 473
 474         return 0;
 475 }
 476
 477 static int omap_rtc_resume(struct platform_device *pdev)
 478 {
 479         if (device_may_wakeup(&pdev->dev))
 480                 disable_irq_wake(omap_rtc_alarm);
 481         else
 482                 rtc_write(irqstat, OMAP_RTC_INTERRUPTS_REG);
 483         return 0;
 484 }
 485
 486 #else
 487 #define omap_rtc_suspend NULL
 488 #define omap_rtc_resume  NULL
 489 #endif
 490
 491 static void omap_rtc_shutdown(struct platform_device *pdev)
 492 {
 493         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 494 }
 495
 496 MODULE_ALIAS("platform:omap_rtc");
 497 static struct platform_driver omap_rtc_driver = {
 498         .remove         = __exit_p(omap_rtc_remove),
 499         .suspend        = omap_rtc_suspend,
 500         .resume         = omap_rtc_resume,
 501         .shutdown       = omap_rtc_shutdown,
 502         .driver         = {
 503                 .name   = "omap_rtc",
 504                 .owner  = THIS_MODULE,
 505         },
 506 };
 507
 508 static int __init rtc_init(void)
 509 {
 510         return platform_driver_probe(&omap_rtc_driver, omap_rtc_probe);
 511 }
 512 module_init(rtc_init);
 513
 514 static void __exit rtc_exit(void)
 515 {
 516         platform_driver_unregister(&omap_rtc_driver);
 517 }
 518 module_exit(rtc_exit);
 519
 520 MODULE_AUTHOR("George G. Davis (and others)");
 521 MODULE_LICENSE("GPL");