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 /* we rely on the rtc framework to handle locking (rtc->ops_lock),
  96  * so the only other requirement is that register accesses which
  97  * require BUSY to be clear are made with IRQs locally disabled
  98  */
  99 static void rtc_wait_not_busy(void)
 100 {
 101         int     count = 0;
 102         u8      status;
 103
 104         /* BUSY may stay active for 1/32768 second (~30 usec) */
 105         for (count = 0; count < 50; count++) {
 106                 status = rtc_read(OMAP_RTC_STATUS_REG);
 107                 if ((status & (u8)OMAP_RTC_STATUS_BUSY) == 0)
 108                         break;
 109                 udelay(1);
 110         }
 111         /* now we have ~15 usec to read/write various registers */
 112 }
 113
 114 static irqreturn_t rtc_irq(int irq, void *rtc)
 115 {
 116         unsigned long           events = 0;
 117         u8                      irq_data;
 118
 119         irq_data = rtc_read(OMAP_RTC_STATUS_REG);
 120
 121         /* alarm irq? */
 122         if (irq_data & OMAP_RTC_STATUS_ALARM) {
 123                 rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
 124                 events |= RTC_IRQF | RTC_AF;
 125         }
 126
 127         /* 1/sec periodic/update irq? */
 128         if (irq_data & OMAP_RTC_STATUS_1S_EVENT)
 129                 events |= RTC_IRQF | RTC_UF;
 130
 131         rtc_update_irq(rtc, 1, events);
 132
 133         return IRQ_HANDLED;
 134 }
 135
 136 #ifdef  CONFIG_RTC_INTF_DEV
 137
 138 static int
 139 omap_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 140 {
 141         u8 reg;
 142
 143         switch (cmd) {
 144         case RTC_AIE_OFF:
 145         case RTC_AIE_ON:
 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         /* AIE = Alarm Interrupt Enable */
 158         case RTC_AIE_OFF:
 159                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 160                 break;
 161         case RTC_AIE_ON:
 162                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 163                 break;
 164         /* UIE = Update Interrupt Enable (1/second) */
 165         case RTC_UIE_OFF:
 166                 reg &= ~OMAP_RTC_INTERRUPTS_IT_TIMER;
 167                 break;
 168         case RTC_UIE_ON:
 169                 reg |= OMAP_RTC_INTERRUPTS_IT_TIMER;
 170                 break;
 171         }
 172         rtc_wait_not_busy();
 173         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 174         local_irq_enable();
 175
 176         return 0;
 177 }
 178
 179 #else
 180 #define omap_rtc_ioctl  NULL
 181 #endif
 182
 183 /* this hardware doesn't support "don't care" alarm fields */
 184 static int tm2bcd(struct rtc_time *tm)
 185 {
 186         if (rtc_valid_tm(tm) != 0)
 187                 return -EINVAL;
 188
 189         tm->tm_sec = BIN2BCD(tm->tm_sec);
 190         tm->tm_min = BIN2BCD(tm->tm_min);
 191         tm->tm_hour = BIN2BCD(tm->tm_hour);
 192         tm->tm_mday = BIN2BCD(tm->tm_mday);
 193
 194         tm->tm_mon = BIN2BCD(tm->tm_mon + 1);
 195
 196         /* epoch == 1900 */
 197         if (tm->tm_year < 100 || tm->tm_year > 199)
 198                 return -EINVAL;
 199         tm->tm_year = BIN2BCD(tm->tm_year - 100);
 200
 201         return 0;
 202 }
 203
 204 static void bcd2tm(struct rtc_time *tm)
 205 {
 206         tm->tm_sec = BCD2BIN(tm->tm_sec);
 207         tm->tm_min = BCD2BIN(tm->tm_min);
 208         tm->tm_hour = BCD2BIN(tm->tm_hour);
 209         tm->tm_mday = BCD2BIN(tm->tm_mday);
 210         tm->tm_mon = BCD2BIN(tm->tm_mon) - 1;
 211         /* epoch == 1900 */
 212         tm->tm_year = BCD2BIN(tm->tm_year) + 100;
 213 }
 214
 215
 216 static int omap_rtc_read_time(struct device *dev, struct rtc_time *tm)
 217 {
 218         /* we don't report wday/yday/isdst ... */
 219         local_irq_disable();
 220         rtc_wait_not_busy();
 221
 222         tm->tm_sec = rtc_read(OMAP_RTC_SECONDS_REG);
 223         tm->tm_min = rtc_read(OMAP_RTC_MINUTES_REG);
 224         tm->tm_hour = rtc_read(OMAP_RTC_HOURS_REG);
 225         tm->tm_mday = rtc_read(OMAP_RTC_DAYS_REG);
 226         tm->tm_mon = rtc_read(OMAP_RTC_MONTHS_REG);
 227         tm->tm_year = rtc_read(OMAP_RTC_YEARS_REG);
 228
 229         local_irq_enable();
 230
 231         bcd2tm(tm);
 232         return 0;
 233 }
 234
 235 static int omap_rtc_set_time(struct device *dev, struct rtc_time *tm)
 236 {
 237         if (tm2bcd(tm) < 0)
 238                 return -EINVAL;
 239         local_irq_disable();
 240         rtc_wait_not_busy();
 241
 242         rtc_write(tm->tm_year, OMAP_RTC_YEARS_REG);
 243         rtc_write(tm->tm_mon, OMAP_RTC_MONTHS_REG);
 244         rtc_write(tm->tm_mday, OMAP_RTC_DAYS_REG);
 245         rtc_write(tm->tm_hour, OMAP_RTC_HOURS_REG);
 246         rtc_write(tm->tm_min, OMAP_RTC_MINUTES_REG);
 247         rtc_write(tm->tm_sec, OMAP_RTC_SECONDS_REG);
 248
 249         local_irq_enable();
 250
 251         return 0;
 252 }
 253
 254 static int omap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 255 {
 256         local_irq_disable();
 257         rtc_wait_not_busy();
 258
 259         alm->time.tm_sec = rtc_read(OMAP_RTC_ALARM_SECONDS_REG);
 260         alm->time.tm_min = rtc_read(OMAP_RTC_ALARM_MINUTES_REG);
 261         alm->time.tm_hour = rtc_read(OMAP_RTC_ALARM_HOURS_REG);
 262         alm->time.tm_mday = rtc_read(OMAP_RTC_ALARM_DAYS_REG);
 263         alm->time.tm_mon = rtc_read(OMAP_RTC_ALARM_MONTHS_REG);
 264         alm->time.tm_year = rtc_read(OMAP_RTC_ALARM_YEARS_REG);
 265
 266         local_irq_enable();
 267
 268         bcd2tm(&alm->time);
 269         alm->enabled = !!(rtc_read(OMAP_RTC_INTERRUPTS_REG)
 270                         & OMAP_RTC_INTERRUPTS_IT_ALARM);
 271
 272         return 0;
 273 }
 274
 275 static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 276 {
 277         u8 reg;
 278
 279         if (tm2bcd(&alm->time) < 0)
 280                 return -EINVAL;
 281
 282         local_irq_disable();
 283         rtc_wait_not_busy();
 284
 285         rtc_write(alm->time.tm_year, OMAP_RTC_ALARM_YEARS_REG);
 286         rtc_write(alm->time.tm_mon, OMAP_RTC_ALARM_MONTHS_REG);
 287         rtc_write(alm->time.tm_mday, OMAP_RTC_ALARM_DAYS_REG);
 288         rtc_write(alm->time.tm_hour, OMAP_RTC_ALARM_HOURS_REG);
 289         rtc_write(alm->time.tm_min, OMAP_RTC_ALARM_MINUTES_REG);
 290         rtc_write(alm->time.tm_sec, OMAP_RTC_ALARM_SECONDS_REG);
 291
 292         reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 293         if (alm->enabled)
 294                 reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 295         else
 296                 reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 297         rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 298
 299         local_irq_enable();
 300
 301         return 0;
 302 }
 303
 304 static struct rtc_class_ops omap_rtc_ops = {
 305         .ioctl          = omap_rtc_ioctl,
 306         .read_time      = omap_rtc_read_time,
 307         .set_time       = omap_rtc_set_time,
 308         .read_alarm     = omap_rtc_read_alarm,
 309         .set_alarm      = omap_rtc_set_alarm,
 310 };
 311
 312 static int omap_rtc_alarm;
 313 static int omap_rtc_timer;
 314
 315 static int __init omap_rtc_probe(struct platform_device *pdev)
 316 {
 317         struct resource         *res, *mem;
 318         struct rtc_device       *rtc;
 319         u8                      reg, new_ctrl;
 320
 321         omap_rtc_timer = platform_get_irq(pdev, 0);
 322         if (omap_rtc_timer <= 0) {
 323                 pr_debug("%s: no update irq?\n", pdev->name);
 324                 return -ENOENT;
 325         }
 326
 327         omap_rtc_alarm = platform_get_irq(pdev, 1);
 328         if (omap_rtc_alarm <= 0) {
 329                 pr_debug("%s: no alarm irq?\n", pdev->name);
 330                 return -ENOENT;
 331         }
 332
 333         /* NOTE:  using static mapping for RTC registers */
 334         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 335         if (res && res->start != OMAP_RTC_BASE) {
 336                 pr_debug("%s: RTC registers at %08x, expected %08x\n",
 337                         pdev->name, (unsigned) res->start, OMAP_RTC_BASE);
 338                 return -ENOENT;
 339         }
 340
 341         if (res)
 342                 mem = request_mem_region(res->start,
 343                                 res->end - res->start + 1,
 344                                 pdev->name);
 345         else
 346                 mem = NULL;
 347         if (!mem) {
 348                 pr_debug("%s: RTC registers at %08x are not free\n",
 349                         pdev->name, OMAP_RTC_BASE);
 350                 return -EBUSY;
 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 fail;
 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                         rtc->dev.bus_id, rtc)) {
 381                 pr_debug("%s: RTC timer interrupt IRQ%d already claimed\n",
 382                         pdev->name, omap_rtc_timer);
 383                 goto fail0;
 384         }
 385         if (request_irq(omap_rtc_alarm, rtc_irq, IRQF_DISABLED,
 386                         rtc->dev.bus_id, rtc)) {
 387                 pr_debug("%s: RTC alarm interrupt IRQ%d already claimed\n",
 388                         pdev->name, omap_rtc_alarm);
 389                 goto fail1;
 390         }
 391
 392         /* On boards with split power, RTC_ON_NOFF won't reset the RTC */
 393         reg = rtc_read(OMAP_RTC_CTRL_REG);
 394         if (reg & (u8) OMAP_RTC_CTRL_STOP)
 395                 pr_info("%s: already running\n", pdev->name);
 396
 397         /* force to 24 hour mode */
 398         new_ctrl = reg & ~(OMAP_RTC_CTRL_SPLIT|OMAP_RTC_CTRL_AUTO_COMP);
 399         new_ctrl |= OMAP_RTC_CTRL_STOP;
 400
 401         /* BOARD-SPECIFIC CUSTOMIZATION CAN GO HERE:
 402          *
 403          *  - Boards wired so that RTC_WAKE_INT does something, and muxed
 404          *    right (W13_1610_RTC_WAKE_INT is the default after chip reset),
 405          *    should initialize the device wakeup flag appropriately.
 406          *
 407          *  - Boards wired so RTC_ON_nOFF is used as the reset signal,
 408          *    rather than nPWRON_RESET, should forcibly enable split
 409          *    power mode.  (Some chip errata report that RTC_CTRL_SPLIT
 410          *    is write-only, and always reads as zero...)
 411          */
 412         device_init_wakeup(&pdev->dev, 0);
 413
 414         if (new_ctrl & (u8) OMAP_RTC_CTRL_SPLIT)
 415                 pr_info("%s: split power mode\n", pdev->name);
 416
 417         if (reg != new_ctrl)
 418                 rtc_write(new_ctrl, OMAP_RTC_CTRL_REG);
 419
 420         return 0;
 421
 422 fail1:
 423         free_irq(omap_rtc_timer, NULL);
 424 fail0:
 425         rtc_device_unregister(rtc);
 426 fail:
 427         release_resource(mem);
 428         return -EIO;
 429 }
 430
 431 static int __exit omap_rtc_remove(struct platform_device *pdev)
 432 {
 433         struct rtc_device       *rtc = platform_get_drvdata(pdev);;
 434
 435         device_init_wakeup(&pdev->dev, 0);
 436
 437         /* leave rtc running, but disable irqs */
 438         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 439
 440         free_irq(omap_rtc_timer, rtc);
 441         free_irq(omap_rtc_alarm, rtc);
 442
 443         release_resource(dev_get_drvdata(&rtc->dev));
 444         rtc_device_unregister(rtc);
 445         return 0;
 446 }
 447
 448 #ifdef CONFIG_PM
 449
 450 static u8 irqstat;
 451
 452 static int omap_rtc_suspend(struct platform_device *pdev, pm_message_t state)
 453 {
 454         irqstat = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 455
 456         /* FIXME the RTC alarm is not currently acting as a wakeup event
 457          * source, and in fact this enable() call is just saving a flag
 458          * that's never used...
 459          */
 460         if (device_may_wakeup(&pdev->dev))
 461                 enable_irq_wake(omap_rtc_alarm);
 462         else
 463                 rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 464
 465         return 0;
 466 }
 467
 468 static int omap_rtc_resume(struct platform_device *pdev)
 469 {
 470         if (device_may_wakeup(&pdev->dev))
 471                 disable_irq_wake(omap_rtc_alarm);
 472         else
 473                 rtc_write(irqstat, OMAP_RTC_INTERRUPTS_REG);
 474         return 0;
 475 }
 476
 477 #else
 478 #define omap_rtc_suspend NULL
 479 #define omap_rtc_resume  NULL
 480 #endif
 481
 482 static void omap_rtc_shutdown(struct platform_device *pdev)
 483 {
 484         rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 485 }
 486
 487 MODULE_ALIAS("platform:omap_rtc");
 488 static struct platform_driver omap_rtc_driver = {
 489         .remove         = __exit_p(omap_rtc_remove),
 490         .suspend        = omap_rtc_suspend,
 491         .resume         = omap_rtc_resume,
 492         .shutdown       = omap_rtc_shutdown,
 493         .driver         = {
 494                 .name   = "omap_rtc",
 495                 .owner  = THIS_MODULE,
 496         },
 497 };
 498
 499 static int __init rtc_init(void)
 500 {
 501         return platform_driver_probe(&omap_rtc_driver, omap_rtc_probe);
 502 }
 503 module_init(rtc_init);
 504
 505 static void __exit rtc_exit(void)
 506 {
 507         platform_driver_unregister(&omap_rtc_driver);
 508 }
 509 module_exit(rtc_exit);
 510
 511 MODULE_AUTHOR("George G. Davis (and others)");
 512 MODULE_LICENSE("GPL");