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 static void __iomem     *rtc_base;
  91
  92 #define rtc_read(addr)          __raw_readb(rtc_base + (addr))
  93 #define rtc_write(val, addr)    __raw_writeb(val, rtc_base + (addr))
  94
  95
  96 /* we rely on the rtc framework to handle locking (rtc->ops_lock),
  97  * so the only other requirement is that register accesses which
  98  * require BUSY to be clear are made with IRQs locally disabled
  99  */
 100 static void rtc_wait_not_busy(void)
 101 {
 102         int     count = 0;
 103         u8      status;
 104
 105         /* BUSY may stay active for 1/32768 second (~30 usec) */
 106         for (count = 0; count < 50; count++) {
 107                 status = rtc_read(OMAP_RTC_STATUS_REG);
 108                 if ((status & (u8)OMAP_RTC_STATUS_BUSY) == 0)
 109                         break;
 110                 udelay(1);
 111         }
 112         /* now we have ~15 usec to read/write various registers */
 113 }
 114
 115 static irqreturn_t rtc_irq(int irq, void *rtc)
 116 {
 117         unsigned long           events = 0;
 118         u8                      irq_data;
 119
 120         irq_data = rtc_read(OMAP_RTC_STATUS_REG);
 121
 122         /* alarm irq? */
 123         if (irq_data & OMAP_RTC_STATUS_ALARM) {
 124                 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
 125                 events |= RTC_IRQF | RTC_AF;
 126         }
 127
 128         /* 1/sec periodic/update irq? */
 129         if (irq_data & OMAP_RTC_STATUS_1S_EVENT)
 130                 events |= RTC_IRQF | RTC_UF;
 131
 132         rtc_update_irq(rtc, 1, events);
 133
 134         return IRQ_HANDLED;
 135 }
 136
 137 #ifdef  CONFIG_RTC_INTF_DEV
 138
 139 static int
 140 omap_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 141 {
 142         u8 reg;
 143
 144         switch (cmd) {
 145         case RTC_AIE_OFF:
 146         case RTC_AIE_ON:
 147         case RTC_UIE_OFF:
 148         case RTC_UIE_ON:
 149                 break;
 150         default:
 151                 return -ENOIOCTLCMD;
 152         }
 153
 154         local_irq_disable();
 155         rtc_wait_not_busy();
 156         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 157         switch (cmd) {
 158         /* AIE = Alarm Interrupt Enable */
 159         case RTC_AIE_OFF:
 160                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 161                 break;
 162         case RTC_AIE_ON:
 163                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 164                 break;
 165         /* UIE = Update Interrupt Enable (1/second) */
 166         case RTC_UIE_OFF:
 167                 reg &= ~OMAP_RTC_INTERRUPTS_IT_TIMER;
 168                 break;
 169         case RTC_UIE_ON:
 170                 reg |= OMAP_RTC_INTERRUPTS_IT_TIMER;
 171                 break;
 172         }
 173         rtc_wait_not_busy();
 174         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 175         local_irq_enable();
 176
 177         return 0;
 178 }
 179
 180 #else
 181 #define omap_rtc_ioctl  NULL
 182 #endif
 183
 184 /* this hardware doesn't support "don't care" alarm fields */
 185 static int tm2bcd(struct rtc_time *tm)
 186 {
 187         if (rtc_valid_tm(tm) != 0)
 188                 return -EINVAL;
 189
 190         tm->tm_sec = bin2bcd(tm->tm_sec);
 191         tm->tm_min = bin2bcd(tm->tm_min);
 192         tm->tm_hour = bin2bcd(tm->tm_hour);
 193         tm->tm_mday = bin2bcd(tm->tm_mday);
 194
 195         tm->tm_mon = bin2bcd(tm->tm_mon + 1);
 196
 197         /* epoch == 1900 */
 198         if (tm->tm_year < 100 || tm->tm_year > 199)
 199                 return -EINVAL;
 200         tm->tm_year = bin2bcd(tm->tm_year - 100);
 201
 202         return 0;
 203 }
 204
 205 static void bcd2tm(struct rtc_time *tm)
 206 {
 207         tm->tm_sec = bcd2bin(tm->tm_sec);
 208         tm->tm_min = bcd2bin(tm->tm_min);
 209         tm->tm_hour = bcd2bin(tm->tm_hour);
 210         tm->tm_mday = bcd2bin(tm->tm_mday);
 211         tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
 212         /* epoch == 1900 */
 213         tm->tm_year = bcd2bin(tm->tm_year) + 100;
 214 }
 215
 216
 217 static int omap_rtc_read_time(struct device *dev, struct rtc_time *tm)
 218 {
 219         /* we don't report wday/yday/isdst ... */
 220         local_irq_disable();
 221         rtc_wait_not_busy();
 222
 223         tm->tm_sec = rtc_read(OMAP_RTC_SECONDS_REG);
 224         tm->tm_min = rtc_read(OMAP_RTC_MINUTES_REG);
 225         tm->tm_hour = rtc_read(OMAP_RTC_HOURS_REG);
 226         tm->tm_mday = rtc_read(OMAP_RTC_DAYS_REG);
 227         tm->tm_mon = rtc_read(OMAP_RTC_MONTHS_REG);
 228         tm->tm_year = rtc_read(OMAP_RTC_YEARS_REG);
 229
 230         local_irq_enable();
 231
 232         bcd2tm(tm);
 233         return 0;
 234 }
 235
 236 static int omap_rtc_set_time(struct device *dev, struct rtc_time *tm)
 237 {
 238         if (tm2bcd(tm) < 0)
 239                 return -EINVAL;
 240         local_irq_disable();
 241         rtc_wait_not_busy();
 242
 243         rtc_write(tm->tm_year, OMAP_RTC_YEARS_REG);
 244         rtc_write(tm->tm_mon, OMAP_RTC_MONTHS_REG);
 245         rtc_write(tm->tm_mday, OMAP_RTC_DAYS_REG);
 246         rtc_write(tm->tm_hour, OMAP_RTC_HOURS_REG);
 247         rtc_write(tm->tm_min, OMAP_RTC_MINUTES_REG);
 248         rtc_write(tm->tm_sec, OMAP_RTC_SECONDS_REG);
 249
 250         local_irq_enable();
 251
 252         return 0;
 253 }
 254
 255 static int omap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 256 {
 257         local_irq_disable();
 258         rtc_wait_not_busy();
 259
 260         alm->time.tm_sec = rtc_read(OMAP_RTC_ALARM_SECONDS_REG);
 261         alm->time.tm_min = rtc_read(OMAP_RTC_ALARM_MINUTES_REG);
 262         alm->time.tm_hour = rtc_read(OMAP_RTC_ALARM_HOURS_REG);
 263         alm->time.tm_mday = rtc_read(OMAP_RTC_ALARM_DAYS_REG);
 264         alm->time.tm_mon = rtc_read(OMAP_RTC_ALARM_MONTHS_REG);
 265         alm->time.tm_year = rtc_read(OMAP_RTC_ALARM_YEARS_REG);
 266
 267         local_irq_enable();
 268
 269         bcd2tm(&alm->time);
 270         alm->enabled = !!(rtc_read(OMAP_RTC_INTERRUPTS_REG)
 271                         & OMAP_RTC_INTERRUPTS_IT_ALARM);
 272
 273         return 0;
 274 }
 275
 276 static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 277 {
 278         u8 reg;
 279
 280         if (tm2bcd(&alm->time) < 0)
 281                 return -EINVAL;
 282
 283         local_irq_disable();
 284         rtc_wait_not_busy();
 285
 286         rtc_write(alm->time.tm_year, OMAP_RTC_ALARM_YEARS_REG);
 287         rtc_write(alm->time.tm_mon, OMAP_RTC_ALARM_MONTHS_REG);
 288         rtc_write(alm->time.tm_mday, OMAP_RTC_ALARM_DAYS_REG);
 289         rtc_write(alm->time.tm_hour, OMAP_RTC_ALARM_HOURS_REG);
 290         rtc_write(alm->time.tm_min, OMAP_RTC_ALARM_MINUTES_REG);
 291         rtc_write(alm->time.tm_sec, OMAP_RTC_ALARM_SECONDS_REG);
 292
 293         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 294         if (alm->enabled)
 295                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 296         else
 297                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 298         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 299
 300         local_irq_enable();
 301
 302         return 0;
 303 }
 304
 305 static struct rtc_class_ops omap_rtc_ops = {
 306         .ioctl          = omap_rtc_ioctl,
 307         .read_time      = omap_rtc_read_time,
 308         .set_time       = omap_rtc_set_time,
 309         .read_alarm     = omap_rtc_read_alarm,
 310         .set_alarm      = omap_rtc_set_alarm,
 311 };
 312
 313 static int omap_rtc_alarm;
 314 static int omap_rtc_timer;
 315
 316 static int __init omap_rtc_probe(struct platform_device *pdev)
 317 {
 318         struct resource         *res, *mem;
 319         struct rtc_device       *rtc;
 320         u8                      reg, new_ctrl;
 321
 322         omap_rtc_timer = platform_get_irq(pdev, 0);
 323         if (omap_rtc_timer <= 0) {
 324                 pr_debug("%s: no update irq?\n", pdev->name);
 325                 return -ENOENT;
 326         }
 327
 328         omap_rtc_alarm = platform_get_irq(pdev, 1);
 329         if (omap_rtc_alarm <= 0) {
 330                 pr_debug("%s: no alarm irq?\n", pdev->name);
 331                 return -ENOENT;
 332         }
 333
 334         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 335         if (!res) {
 336                 pr_debug("%s: RTC resource data missing\n", pdev->name);
 337                 return -ENOENT;
 338         }
 339
 340         mem = request_mem_region(res->start, resource_size(res), pdev->name);
 341         if (!mem) {
 342                 pr_debug("%s: RTC registers at %08x are not free\n",
 343                         pdev->name, res->start);
 344                 return -EBUSY;
 345         }
 346
 347         rtc_base = ioremap(res->start, resource_size(res));
 348         if (!rtc_base) {
 349                 pr_debug("%s: RTC registers can't be mapped\n", pdev->name);
 350                 goto fail;
 351         }
 352
 353         rtc = rtc_device_register(pdev->name, &pdev->dev,
 354                         &omap_rtc_ops, THIS_MODULE);
 355         if (IS_ERR(rtc)) {
 356                 pr_debug("%s: can't register RTC device, err %ld\n",
 357                         pdev->name, PTR_ERR(rtc));
 358                 goto fail0;
 359         }
 360         platform_set_drvdata(pdev, rtc);
 361         dev_set_drvdata(&rtc->dev, mem);
 362
 363         /* clear pending irqs, and set 1/second periodic,
 364          * which we'll use instead of update irqs
 365          */
 366         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 367
 368         /* clear old status */
 369         reg = rtc_read(OMAP_RTC_STATUS_REG);
 370         if (reg & (u8) OMAP_RTC_STATUS_POWER_UP) {
 371                 pr_info("%s: RTC power up reset detected\n",
 372                         pdev->name);
 373                 rtc_write(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG);
 374         }
 375         if (reg & (u8) OMAP_RTC_STATUS_ALARM)
 376                 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
 377
 378         /* handle periodic and alarm irqs */
 379         if (request_irq(omap_rtc_timer, rtc_irq, IRQF_DISABLED,
 380                         dev_name(&rtc->dev), rtc)) {
 381                 pr_debug("%s: RTC timer interrupt IRQ%d already claimed\n",
 382                         pdev->name, omap_rtc_timer);
 383                 goto fail1;
 384         }
 385         if ((omap_rtc_timer != omap_rtc_alarm) &&
 386                 (request_irq(omap_rtc_alarm, rtc_irq, IRQF_DISABLED,
 387                         dev_name(&rtc->dev), rtc))) {
 388                 pr_debug("%s: RTC alarm interrupt IRQ%d already claimed\n",
 389                         pdev->name, omap_rtc_alarm);
 390                 goto fail2;
 391         }
 392
 393         /* On boards with split power, RTC_ON_NOFF won't reset the RTC */
 394         reg = rtc_read(OMAP_RTC_CTRL_REG);
 395         if (reg & (u8) OMAP_RTC_CTRL_STOP)
 396                 pr_info("%s: already running\n", pdev->name);
 397
 398         /* force to 24 hour mode */
 399         new_ctrl = reg & ~(OMAP_RTC_CTRL_SPLIT|OMAP_RTC_CTRL_AUTO_COMP);
 400         new_ctrl |= OMAP_RTC_CTRL_STOP;
 401
 402         /* BOARD-SPECIFIC CUSTOMIZATION CAN GO HERE:
 403          *
 404          *  - Boards wired so that RTC_WAKE_INT does something, and muxed
 405          *    right (W13_1610_RTC_WAKE_INT is the default after chip reset),
 406          *    should initialize the device wakeup flag appropriately.
 407          *
 408          *  - Boards wired so RTC_ON_nOFF is used as the reset signal,
 409          *    rather than nPWRON_RESET, should forcibly enable split
 410          *    power mode.  (Some chip errata report that RTC_CTRL_SPLIT
 411          *    is write-only, and always reads as zero...)
 412          */
 413         device_init_wakeup(&pdev->dev, 0);
 414
 415         if (new_ctrl & (u8) OMAP_RTC_CTRL_SPLIT)
 416                 pr_info("%s: split power mode\n", pdev->name);
 417
 418         if (reg != new_ctrl)
 419                 rtc_write(new_ctrl, OMAP_RTC_CTRL_REG);
 420
 421         return 0;
 422
 423 fail2:
 424         free_irq(omap_rtc_timer, NULL);
 425 fail1:
 426         rtc_device_unregister(rtc);
 427 fail0:
 428         iounmap(rtc_base);
 429 fail:
 430         release_resource(mem);
 431         return -EIO;
 432 }
 433
 434 static int __exit omap_rtc_remove(struct platform_device *pdev)
 435 {
 436         struct rtc_device       *rtc = platform_get_drvdata(pdev);
 437
 438         device_init_wakeup(&pdev->dev, 0);
 439
 440         /* leave rtc running, but disable irqs */
 441         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 442
 443         free_irq(omap_rtc_timer, rtc);
 444
 445         if (omap_rtc_timer != omap_rtc_alarm)
 446                 free_irq(omap_rtc_alarm, rtc);
 447
 448         release_resource(dev_get_drvdata(&rtc->dev));
 449         rtc_device_unregister(rtc);
 450         return 0;
 451 }
 452
 453 #ifdef CONFIG_PM
 454
 455 static u8 irqstat;
 456
 457 static int omap_rtc_suspend(struct platform_device *pdev, pm_message_t state)
 458 {
 459         irqstat = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 460
 461         /* FIXME the RTC alarm is not currently acting as a wakeup event
 462          * source, and in fact this enable() call is just saving a flag
 463          * that's never used...
 464          */
 465         if (device_may_wakeup(&pdev->dev))
 466                 enable_irq_wake(omap_rtc_alarm);
 467         else
 468                 rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 469
 470         return 0;
 471 }
 472
 473 static int omap_rtc_resume(struct platform_device *pdev)
 474 {
 475         if (device_may_wakeup(&pdev->dev))
 476                 disable_irq_wake(omap_rtc_alarm);
 477         else
 478                 rtc_write(irqstat, OMAP_RTC_INTERRUPTS_REG);
 479         return 0;
 480 }
 481
 482 #else
 483 #define omap_rtc_suspend NULL
 484 #define omap_rtc_resume  NULL
 485 #endif
 486
 487 static void omap_rtc_shutdown(struct platform_device *pdev)
 488 {
 489         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 490 }
 491
 492 MODULE_ALIAS("platform:omap_rtc");
 493 static struct platform_driver omap_rtc_driver = {
 494         .remove         = __exit_p(omap_rtc_remove),
 495         .suspend        = omap_rtc_suspend,
 496         .resume         = omap_rtc_resume,
 497         .shutdown       = omap_rtc_shutdown,
 498         .driver         = {
 499                 .name   = "omap_rtc",
 500                 .owner  = THIS_MODULE,
 501         },
 502 };
 503
 504 static int __init rtc_init(void)
 505 {
 506         return platform_driver_probe(&omap_rtc_driver, omap_rtc_probe);
 507 }
 508 module_init(rtc_init);
 509
 510 static void __exit rtc_exit(void)
 511 {
 512         platform_driver_unregister(&omap_rtc_driver);
 513 }
 514 module_exit(rtc_exit);
 515
 516 MODULE_AUTHOR("George G. Davis (and others)");
 517 MODULE_LICENSE("GPL");