linux/drivers/rtc/rtc-omap.c
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   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
  27#include <asm/io.h>
  28
  29
  30/* The OMAP1 RTC is a year/month/day/hours/minutes/seconds BCD clock
  31 * with century-range alarm matching, driven by the 32kHz clock.
  32 *
  33 * The main user-visible ways it differs from PC RTCs are by omitting
  34 * "don't care" alarm fields and sub-second periodic IRQs, and having
  35 * an autoadjust mechanism to calibrate to the true oscillator rate.
  36 *
  37 * Board-specific wiring options include using split power mode with
  38 * RTC_OFF_NOFF used as the reset signal (so the RTC won't be reset),
  39 * and wiring RTC_WAKE_INT (so the RTC alarm can wake the system from
  40 * low power modes) for OMAP1 boards (OMAP-L138 has this built into
  41 * the SoC). See the BOARD-SPECIFIC CUSTOMIZATION comment.
  42 */
  43
  44#define DRIVER_NAME                     "omap_rtc"
  45
  46#define OMAP_RTC_BASE                   0xfffb4800
  47
  48/* RTC registers */
  49#define OMAP_RTC_SECONDS_REG            0x00
  50#define OMAP_RTC_MINUTES_REG            0x04
  51#define OMAP_RTC_HOURS_REG              0x08
  52#define OMAP_RTC_DAYS_REG               0x0C
  53#define OMAP_RTC_MONTHS_REG             0x10
  54#define OMAP_RTC_YEARS_REG              0x14
  55#define OMAP_RTC_WEEKS_REG              0x18
  56
  57#define OMAP_RTC_ALARM_SECONDS_REG      0x20
  58#define OMAP_RTC_ALARM_MINUTES_REG      0x24
  59#define OMAP_RTC_ALARM_HOURS_REG        0x28
  60#define OMAP_RTC_ALARM_DAYS_REG         0x2c
  61#define OMAP_RTC_ALARM_MONTHS_REG       0x30
  62#define OMAP_RTC_ALARM_YEARS_REG        0x34
  63
  64#define OMAP_RTC_CTRL_REG               0x40
  65#define OMAP_RTC_STATUS_REG             0x44
  66#define OMAP_RTC_INTERRUPTS_REG         0x48
  67
  68#define OMAP_RTC_COMP_LSB_REG           0x4c
  69#define OMAP_RTC_COMP_MSB_REG           0x50
  70#define OMAP_RTC_OSC_REG                0x54
  71
  72#define OMAP_RTC_KICK0_REG              0x6c
  73#define OMAP_RTC_KICK1_REG              0x70
  74
  75/* OMAP_RTC_CTRL_REG bit fields: */
  76#define OMAP_RTC_CTRL_SPLIT             (1<<7)
  77#define OMAP_RTC_CTRL_DISABLE           (1<<6)
  78#define OMAP_RTC_CTRL_SET_32_COUNTER    (1<<5)
  79#define OMAP_RTC_CTRL_TEST              (1<<4)
  80#define OMAP_RTC_CTRL_MODE_12_24        (1<<3)
  81#define OMAP_RTC_CTRL_AUTO_COMP         (1<<2)
  82#define OMAP_RTC_CTRL_ROUND_30S         (1<<1)
  83#define OMAP_RTC_CTRL_STOP              (1<<0)
  84
  85/* OMAP_RTC_STATUS_REG bit fields: */
  86#define OMAP_RTC_STATUS_POWER_UP        (1<<7)
  87#define OMAP_RTC_STATUS_ALARM           (1<<6)
  88#define OMAP_RTC_STATUS_1D_EVENT        (1<<5)
  89#define OMAP_RTC_STATUS_1H_EVENT        (1<<4)
  90#define OMAP_RTC_STATUS_1M_EVENT        (1<<3)
  91#define OMAP_RTC_STATUS_1S_EVENT        (1<<2)
  92#define OMAP_RTC_STATUS_RUN             (1<<1)
  93#define OMAP_RTC_STATUS_BUSY            (1<<0)
  94
  95/* OMAP_RTC_INTERRUPTS_REG bit fields: */
  96#define OMAP_RTC_INTERRUPTS_IT_ALARM    (1<<3)
  97#define OMAP_RTC_INTERRUPTS_IT_TIMER    (1<<2)
  98
  99/* OMAP_RTC_KICKER values */
 100#define KICK0_VALUE                     0x83e70b13
 101#define KICK1_VALUE                     0x95a4f1e0
 102
 103#define OMAP_RTC_HAS_KICKER             0x1
 104
 105static void __iomem     *rtc_base;
 106
 107#define rtc_read(addr)          readb(rtc_base + (addr))
 108#define rtc_write(val, addr)    writeb(val, rtc_base + (addr))
 109
 110#define rtc_writel(val, addr)   writel(val, rtc_base + (addr))
 111
 112
 113/* we rely on the rtc framework to handle locking (rtc->ops_lock),
 114 * so the only other requirement is that register accesses which
 115 * require BUSY to be clear are made with IRQs locally disabled
 116 */
 117static void rtc_wait_not_busy(void)
 118{
 119        int     count = 0;
 120        u8      status;
 121
 122        /* BUSY may stay active for 1/32768 second (~30 usec) */
 123        for (count = 0; count < 50; count++) {
 124                status = rtc_read(OMAP_RTC_STATUS_REG);
 125                if ((status & (u8)OMAP_RTC_STATUS_BUSY) == 0)
 126                        break;
 127                udelay(1);
 128        }
 129        /* now we have ~15 usec to read/write various registers */
 130}
 131
 132static irqreturn_t rtc_irq(int irq, void *rtc)
 133{
 134        unsigned long           events = 0;
 135        u8                      irq_data;
 136
 137        irq_data = rtc_read(OMAP_RTC_STATUS_REG);
 138
 139        /* alarm irq? */
 140        if (irq_data & OMAP_RTC_STATUS_ALARM) {
 141                rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
 142                events |= RTC_IRQF | RTC_AF;
 143        }
 144
 145        /* 1/sec periodic/update irq? */
 146        if (irq_data & OMAP_RTC_STATUS_1S_EVENT)
 147                events |= RTC_IRQF | RTC_UF;
 148
 149        rtc_update_irq(rtc, 1, events);
 150
 151        return IRQ_HANDLED;
 152}
 153
 154static int omap_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 155{
 156        u8 reg;
 157
 158        local_irq_disable();
 159        rtc_wait_not_busy();
 160        reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 161        if (enabled)
 162                reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 163        else
 164                reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 165        rtc_wait_not_busy();
 166        rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 167        local_irq_enable();
 168
 169        return 0;
 170}
 171
 172/* this hardware doesn't support "don't care" alarm fields */
 173static int tm2bcd(struct rtc_time *tm)
 174{
 175        if (rtc_valid_tm(tm) != 0)
 176                return -EINVAL;
 177
 178        tm->tm_sec = bin2bcd(tm->tm_sec);
 179        tm->tm_min = bin2bcd(tm->tm_min);
 180        tm->tm_hour = bin2bcd(tm->tm_hour);
 181        tm->tm_mday = bin2bcd(tm->tm_mday);
 182
 183        tm->tm_mon = bin2bcd(tm->tm_mon + 1);
 184
 185        /* epoch == 1900 */
 186        if (tm->tm_year < 100 || tm->tm_year > 199)
 187                return -EINVAL;
 188        tm->tm_year = bin2bcd(tm->tm_year - 100);
 189
 190        return 0;
 191}
 192
 193static void bcd2tm(struct rtc_time *tm)
 194{
 195        tm->tm_sec = bcd2bin(tm->tm_sec);
 196        tm->tm_min = bcd2bin(tm->tm_min);
 197        tm->tm_hour = bcd2bin(tm->tm_hour);
 198        tm->tm_mday = bcd2bin(tm->tm_mday);
 199        tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
 200        /* epoch == 1900 */
 201        tm->tm_year = bcd2bin(tm->tm_year) + 100;
 202}
 203
 204
 205static int omap_rtc_read_time(struct device *dev, struct rtc_time *tm)
 206{
 207        /* we don't report wday/yday/isdst ... */
 208        local_irq_disable();
 209        rtc_wait_not_busy();
 210
 211        tm->tm_sec = rtc_read(OMAP_RTC_SECONDS_REG);
 212        tm->tm_min = rtc_read(OMAP_RTC_MINUTES_REG);
 213        tm->tm_hour = rtc_read(OMAP_RTC_HOURS_REG);
 214        tm->tm_mday = rtc_read(OMAP_RTC_DAYS_REG);
 215        tm->tm_mon = rtc_read(OMAP_RTC_MONTHS_REG);
 216        tm->tm_year = rtc_read(OMAP_RTC_YEARS_REG);
 217
 218        local_irq_enable();
 219
 220        bcd2tm(tm);
 221        return 0;
 222}
 223
 224static int omap_rtc_set_time(struct device *dev, struct rtc_time *tm)
 225{
 226        if (tm2bcd(tm) < 0)
 227                return -EINVAL;
 228        local_irq_disable();
 229        rtc_wait_not_busy();
 230
 231        rtc_write(tm->tm_year, OMAP_RTC_YEARS_REG);
 232        rtc_write(tm->tm_mon, OMAP_RTC_MONTHS_REG);
 233        rtc_write(tm->tm_mday, OMAP_RTC_DAYS_REG);
 234        rtc_write(tm->tm_hour, OMAP_RTC_HOURS_REG);
 235        rtc_write(tm->tm_min, OMAP_RTC_MINUTES_REG);
 236        rtc_write(tm->tm_sec, OMAP_RTC_SECONDS_REG);
 237
 238        local_irq_enable();
 239
 240        return 0;
 241}
 242
 243static int omap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 244{
 245        local_irq_disable();
 246        rtc_wait_not_busy();
 247
 248        alm->time.tm_sec = rtc_read(OMAP_RTC_ALARM_SECONDS_REG);
 249        alm->time.tm_min = rtc_read(OMAP_RTC_ALARM_MINUTES_REG);
 250        alm->time.tm_hour = rtc_read(OMAP_RTC_ALARM_HOURS_REG);
 251        alm->time.tm_mday = rtc_read(OMAP_RTC_ALARM_DAYS_REG);
 252        alm->time.tm_mon = rtc_read(OMAP_RTC_ALARM_MONTHS_REG);
 253        alm->time.tm_year = rtc_read(OMAP_RTC_ALARM_YEARS_REG);
 254
 255        local_irq_enable();
 256
 257        bcd2tm(&alm->time);
 258        alm->enabled = !!(rtc_read(OMAP_RTC_INTERRUPTS_REG)
 259                        & OMAP_RTC_INTERRUPTS_IT_ALARM);
 260
 261        return 0;
 262}
 263
 264static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 265{
 266        u8 reg;
 267
 268        if (tm2bcd(&alm->time) < 0)
 269                return -EINVAL;
 270
 271        local_irq_disable();
 272        rtc_wait_not_busy();
 273
 274        rtc_write(alm->time.tm_year, OMAP_RTC_ALARM_YEARS_REG);
 275        rtc_write(alm->time.tm_mon, OMAP_RTC_ALARM_MONTHS_REG);
 276        rtc_write(alm->time.tm_mday, OMAP_RTC_ALARM_DAYS_REG);
 277        rtc_write(alm->time.tm_hour, OMAP_RTC_ALARM_HOURS_REG);
 278        rtc_write(alm->time.tm_min, OMAP_RTC_ALARM_MINUTES_REG);
 279        rtc_write(alm->time.tm_sec, OMAP_RTC_ALARM_SECONDS_REG);
 280
 281        reg = rtc_read(OMAP_RTC_INTERRUPTS_REG);
 282        if (alm->enabled)
 283                reg |= OMAP_RTC_INTERRUPTS_IT_ALARM;
 284        else
 285                reg &= ~OMAP_RTC_INTERRUPTS_IT_ALARM;
 286        rtc_write(reg, OMAP_RTC_INTERRUPTS_REG);
 287
 288        local_irq_enable();
 289
 290        return 0;
 291}
 292
 293static struct rtc_class_ops omap_rtc_ops = {
 294        .read_time      = omap_rtc_read_time,
 295        .set_time       = omap_rtc_set_time,
 296        .read_alarm     = omap_rtc_read_alarm,
 297        .set_alarm      = omap_rtc_set_alarm,
 298        .alarm_irq_enable = omap_rtc_alarm_irq_enable,
 299};
 300
 301static int omap_rtc_alarm;
 302static int omap_rtc_timer;
 303
 304#define OMAP_RTC_DATA_DA830_IDX 1
 305
 306static struct platform_device_id omap_rtc_devtype[] = {
 307        {
 308                .name   = DRIVER_NAME,
 309        }, {
 310                .name   = "da830-rtc",
 311                .driver_data = OMAP_RTC_HAS_KICKER,
 312        },
 313        {},
 314};
 315MODULE_DEVICE_TABLE(platform, omap_rtc_devtype);
 316
 317static const struct of_device_id omap_rtc_of_match[] = {
 318        {       .compatible     = "ti,da830-rtc",
 319                .data           = &omap_rtc_devtype[OMAP_RTC_DATA_DA830_IDX],
 320        },
 321        {},
 322};
 323MODULE_DEVICE_TABLE(of, omap_rtc_of_match);
 324
 325static int __init omap_rtc_probe(struct platform_device *pdev)
 326{
 327        struct resource         *res;
 328        struct rtc_device       *rtc;
 329        u8                      reg, new_ctrl;
 330        const struct platform_device_id *id_entry;
 331        const struct of_device_id *of_id;
 332
 333        of_id = of_match_device(omap_rtc_of_match, &pdev->dev);
 334        if (of_id)
 335                pdev->id_entry = of_id->data;
 336
 337        omap_rtc_timer = platform_get_irq(pdev, 0);
 338        if (omap_rtc_timer <= 0) {
 339                pr_debug("%s: no update irq?\n", pdev->name);
 340                return -ENOENT;
 341        }
 342
 343        omap_rtc_alarm = platform_get_irq(pdev, 1);
 344        if (omap_rtc_alarm <= 0) {
 345                pr_debug("%s: no alarm irq?\n", pdev->name);
 346                return -ENOENT;
 347        }
 348
 349        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 350        rtc_base = devm_ioremap_resource(&pdev->dev, res);
 351        if (IS_ERR(rtc_base))
 352                return PTR_ERR(rtc_base);
 353
 354        /* Enable the clock/module so that we can access the registers */
 355        pm_runtime_enable(&pdev->dev);
 356        pm_runtime_get_sync(&pdev->dev);
 357
 358        id_entry = platform_get_device_id(pdev);
 359        if (id_entry && (id_entry->driver_data & OMAP_RTC_HAS_KICKER)) {
 360                rtc_writel(KICK0_VALUE, OMAP_RTC_KICK0_REG);
 361                rtc_writel(KICK1_VALUE, OMAP_RTC_KICK1_REG);
 362        }
 363
 364        rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
 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
 373        /* clear pending irqs, and set 1/second periodic,
 374         * which we'll use instead of update irqs
 375         */
 376        rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 377
 378        /* clear old status */
 379        reg = rtc_read(OMAP_RTC_STATUS_REG);
 380        if (reg & (u8) OMAP_RTC_STATUS_POWER_UP) {
 381                pr_info("%s: RTC power up reset detected\n",
 382                        pdev->name);
 383                rtc_write(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG);
 384        }
 385        if (reg & (u8) OMAP_RTC_STATUS_ALARM)
 386                rtc_write(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
 387
 388        /* handle periodic and alarm irqs */
 389        if (devm_request_irq(&pdev->dev, omap_rtc_timer, rtc_irq, 0,
 390                        dev_name(&rtc->dev), rtc)) {
 391                pr_debug("%s: RTC timer interrupt IRQ%d already claimed\n",
 392                        pdev->name, omap_rtc_timer);
 393                goto fail0;
 394        }
 395        if ((omap_rtc_timer != omap_rtc_alarm) &&
 396                (devm_request_irq(&pdev->dev, omap_rtc_alarm, rtc_irq, 0,
 397                        dev_name(&rtc->dev), rtc))) {
 398                pr_debug("%s: RTC alarm interrupt IRQ%d already claimed\n",
 399                        pdev->name, omap_rtc_alarm);
 400                goto fail0;
 401        }
 402
 403        /* On boards with split power, RTC_ON_NOFF won't reset the RTC */
 404        reg = rtc_read(OMAP_RTC_CTRL_REG);
 405        if (reg & (u8) OMAP_RTC_CTRL_STOP)
 406                pr_info("%s: already running\n", pdev->name);
 407
 408        /* force to 24 hour mode */
 409        new_ctrl = reg & (OMAP_RTC_CTRL_SPLIT|OMAP_RTC_CTRL_AUTO_COMP);
 410        new_ctrl |= OMAP_RTC_CTRL_STOP;
 411
 412        /* BOARD-SPECIFIC CUSTOMIZATION CAN GO HERE:
 413         *
 414         *  - Device wake-up capability setting should come through chip
 415         *    init logic. OMAP1 boards should initialize the "wakeup capable"
 416         *    flag in the platform device if the board is wired right for
 417         *    being woken up by RTC alarm. For OMAP-L138, this capability
 418         *    is built into the SoC by the "Deep Sleep" capability.
 419         *
 420         *  - Boards wired so RTC_ON_nOFF is used as the reset signal,
 421         *    rather than nPWRON_RESET, should forcibly enable split
 422         *    power mode.  (Some chip errata report that RTC_CTRL_SPLIT
 423         *    is write-only, and always reads as zero...)
 424         */
 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
 434fail0:
 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
 442static 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
 463static u8 irqstat;
 464
 465static 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
 484static 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
 497static SIMPLE_DEV_PM_OPS(omap_rtc_pm_ops, omap_rtc_suspend, omap_rtc_resume);
 498
 499static void omap_rtc_shutdown(struct platform_device *pdev)
 500{
 501        rtc_write(0, OMAP_RTC_INTERRUPTS_REG);
 502}
 503
 504MODULE_ALIAS("platform:omap_rtc");
 505static 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
 517module_platform_driver_probe(omap_rtc_driver, omap_rtc_probe);
 518
 519MODULE_AUTHOR("George G. Davis (and others)");
 520MODULE_LICENSE("GPL");
 521
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