linux/drivers/rtc/rtc-at91rm9200.c
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   1/*
   2 *      Real Time Clock interface for Linux on Atmel AT91RM9200
   3 *
   4 *      Copyright (C) 2002 Rick Bronson
   5 *
   6 *      Converted to RTC class model by Andrew Victor
   7 *
   8 *      Ported to Linux 2.6 by Steven Scholz
   9 *      Based on s3c2410-rtc.c Simtec Electronics
  10 *
  11 *      Based on sa1100-rtc.c by Nils Faerber
  12 *      Based on rtc.c by Paul Gortmaker
  13 *
  14 *      This program is free software; you can redistribute it and/or
  15 *      modify it under the terms of the GNU General Public License
  16 *      as published by the Free Software Foundation; either version
  17 *      2 of the License, or (at your option) any later version.
  18 *
  19 */
  20
  21#include <linux/module.h>
  22#include <linux/kernel.h>
  23#include <linux/platform_device.h>
  24#include <linux/time.h>
  25#include <linux/rtc.h>
  26#include <linux/bcd.h>
  27#include <linux/interrupt.h>
  28#include <linux/spinlock.h>
  29#include <linux/ioctl.h>
  30#include <linux/completion.h>
  31#include <linux/io.h>
  32#include <linux/of.h>
  33#include <linux/of_device.h>
  34#include <linux/uaccess.h>
  35
  36#include "rtc-at91rm9200.h"
  37
  38#define at91_rtc_read(field) \
  39        __raw_readl(at91_rtc_regs + field)
  40#define at91_rtc_write(field, val) \
  41        __raw_writel((val), at91_rtc_regs + field)
  42
  43#define AT91_RTC_EPOCH          1900UL  /* just like arch/arm/common/rtctime.c */
  44
  45struct at91_rtc_config {
  46        bool use_shadow_imr;
  47};
  48
  49static const struct at91_rtc_config *at91_rtc_config;
  50static DECLARE_COMPLETION(at91_rtc_updated);
  51static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
  52static void __iomem *at91_rtc_regs;
  53static int irq;
  54static DEFINE_SPINLOCK(at91_rtc_lock);
  55static u32 at91_rtc_shadow_imr;
  56
  57static void at91_rtc_write_ier(u32 mask)
  58{
  59        unsigned long flags;
  60
  61        spin_lock_irqsave(&at91_rtc_lock, flags);
  62        at91_rtc_shadow_imr |= mask;
  63        at91_rtc_write(AT91_RTC_IER, mask);
  64        spin_unlock_irqrestore(&at91_rtc_lock, flags);
  65}
  66
  67static void at91_rtc_write_idr(u32 mask)
  68{
  69        unsigned long flags;
  70
  71        spin_lock_irqsave(&at91_rtc_lock, flags);
  72        at91_rtc_write(AT91_RTC_IDR, mask);
  73        /*
  74         * Register read back (of any RTC-register) needed to make sure
  75         * IDR-register write has reached the peripheral before updating
  76         * shadow mask.
  77         *
  78         * Note that there is still a possibility that the mask is updated
  79         * before interrupts have actually been disabled in hardware. The only
  80         * way to be certain would be to poll the IMR-register, which is is
  81         * the very register we are trying to emulate. The register read back
  82         * is a reasonable heuristic.
  83         */
  84        at91_rtc_read(AT91_RTC_SR);
  85        at91_rtc_shadow_imr &= ~mask;
  86        spin_unlock_irqrestore(&at91_rtc_lock, flags);
  87}
  88
  89static u32 at91_rtc_read_imr(void)
  90{
  91        unsigned long flags;
  92        u32 mask;
  93
  94        if (at91_rtc_config->use_shadow_imr) {
  95                spin_lock_irqsave(&at91_rtc_lock, flags);
  96                mask = at91_rtc_shadow_imr;
  97                spin_unlock_irqrestore(&at91_rtc_lock, flags);
  98        } else {
  99                mask = at91_rtc_read(AT91_RTC_IMR);
 100        }
 101
 102        return mask;
 103}
 104
 105/*
 106 * Decode time/date into rtc_time structure
 107 */
 108static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
 109                                struct rtc_time *tm)
 110{
 111        unsigned int time, date;
 112
 113        /* must read twice in case it changes */
 114        do {
 115                time = at91_rtc_read(timereg);
 116                date = at91_rtc_read(calreg);
 117        } while ((time != at91_rtc_read(timereg)) ||
 118                        (date != at91_rtc_read(calreg)));
 119
 120        tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
 121        tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
 122        tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
 123
 124        /*
 125         * The Calendar Alarm register does not have a field for
 126         * the year - so these will return an invalid value.  When an
 127         * alarm is set, at91_alarm_year will store the current year.
 128         */
 129        tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;     /* century */
 130        tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);    /* year */
 131
 132        tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
 133        tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
 134        tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
 135}
 136
 137/*
 138 * Read current time and date in RTC
 139 */
 140static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
 141{
 142        at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
 143        tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 144        tm->tm_year = tm->tm_year - 1900;
 145
 146        dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 147                1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 148                tm->tm_hour, tm->tm_min, tm->tm_sec);
 149
 150        return 0;
 151}
 152
 153/*
 154 * Set current time and date in RTC
 155 */
 156static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
 157{
 158        unsigned long cr;
 159
 160        dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 161                1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 162                tm->tm_hour, tm->tm_min, tm->tm_sec);
 163
 164        /* Stop Time/Calendar from counting */
 165        cr = at91_rtc_read(AT91_RTC_CR);
 166        at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
 167
 168        at91_rtc_write_ier(AT91_RTC_ACKUPD);
 169        wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
 170        at91_rtc_write_idr(AT91_RTC_ACKUPD);
 171
 172        at91_rtc_write(AT91_RTC_TIMR,
 173                          bin2bcd(tm->tm_sec) << 0
 174                        | bin2bcd(tm->tm_min) << 8
 175                        | bin2bcd(tm->tm_hour) << 16);
 176
 177        at91_rtc_write(AT91_RTC_CALR,
 178                          bin2bcd((tm->tm_year + 1900) / 100)   /* century */
 179                        | bin2bcd(tm->tm_year % 100) << 8       /* year */
 180                        | bin2bcd(tm->tm_mon + 1) << 16         /* tm_mon starts at zero */
 181                        | bin2bcd(tm->tm_wday + 1) << 21        /* day of the week [0-6], Sunday=0 */
 182                        | bin2bcd(tm->tm_mday) << 24);
 183
 184        /* Restart Time/Calendar */
 185        cr = at91_rtc_read(AT91_RTC_CR);
 186        at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
 187
 188        return 0;
 189}
 190
 191/*
 192 * Read alarm time and date in RTC
 193 */
 194static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 195{
 196        struct rtc_time *tm = &alrm->time;
 197
 198        at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
 199        tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 200        tm->tm_year = at91_alarm_year - 1900;
 201
 202        alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
 203                        ? 1 : 0;
 204
 205        dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 206                1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 207                tm->tm_hour, tm->tm_min, tm->tm_sec);
 208
 209        return 0;
 210}
 211
 212/*
 213 * Set alarm time and date in RTC
 214 */
 215static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 216{
 217        struct rtc_time tm;
 218
 219        at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
 220
 221        at91_alarm_year = tm.tm_year;
 222
 223        tm.tm_hour = alrm->time.tm_hour;
 224        tm.tm_min = alrm->time.tm_min;
 225        tm.tm_sec = alrm->time.tm_sec;
 226
 227        at91_rtc_write_idr(AT91_RTC_ALARM);
 228        at91_rtc_write(AT91_RTC_TIMALR,
 229                  bin2bcd(tm.tm_sec) << 0
 230                | bin2bcd(tm.tm_min) << 8
 231                | bin2bcd(tm.tm_hour) << 16
 232                | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
 233        at91_rtc_write(AT91_RTC_CALALR,
 234                  bin2bcd(tm.tm_mon + 1) << 16          /* tm_mon starts at zero */
 235                | bin2bcd(tm.tm_mday) << 24
 236                | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
 237
 238        if (alrm->enabled) {
 239                at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 240                at91_rtc_write_ier(AT91_RTC_ALARM);
 241        }
 242
 243        dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 244                at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
 245                tm.tm_min, tm.tm_sec);
 246
 247        return 0;
 248}
 249
 250static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 251{
 252        dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
 253
 254        if (enabled) {
 255                at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 256                at91_rtc_write_ier(AT91_RTC_ALARM);
 257        } else
 258                at91_rtc_write_idr(AT91_RTC_ALARM);
 259
 260        return 0;
 261}
 262/*
 263 * Provide additional RTC information in /proc/driver/rtc
 264 */
 265static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
 266{
 267        unsigned long imr = at91_rtc_read_imr();
 268
 269        seq_printf(seq, "update_IRQ\t: %s\n",
 270                        (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
 271        seq_printf(seq, "periodic_IRQ\t: %s\n",
 272                        (imr & AT91_RTC_SECEV) ? "yes" : "no");
 273
 274        return 0;
 275}
 276
 277/*
 278 * IRQ handler for the RTC
 279 */
 280static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
 281{
 282        struct platform_device *pdev = dev_id;
 283        struct rtc_device *rtc = platform_get_drvdata(pdev);
 284        unsigned int rtsr;
 285        unsigned long events = 0;
 286
 287        rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
 288        if (rtsr) {             /* this interrupt is shared!  Is it ours? */
 289                if (rtsr & AT91_RTC_ALARM)
 290                        events |= (RTC_AF | RTC_IRQF);
 291                if (rtsr & AT91_RTC_SECEV)
 292                        events |= (RTC_UF | RTC_IRQF);
 293                if (rtsr & AT91_RTC_ACKUPD)
 294                        complete(&at91_rtc_updated);
 295
 296                at91_rtc_write(AT91_RTC_SCCR, rtsr);    /* clear status reg */
 297
 298                rtc_update_irq(rtc, 1, events);
 299
 300                dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", __func__,
 301                        events >> 8, events & 0x000000FF);
 302
 303                return IRQ_HANDLED;
 304        }
 305        return IRQ_NONE;                /* not handled */
 306}
 307
 308static const struct at91_rtc_config at91rm9200_config = {
 309};
 310
 311static const struct at91_rtc_config at91sam9x5_config = {
 312        .use_shadow_imr = true,
 313};
 314
 315#ifdef CONFIG_OF
 316static const struct of_device_id at91_rtc_dt_ids[] = {
 317        {
 318                .compatible = "atmel,at91rm9200-rtc",
 319                .data = &at91rm9200_config,
 320        }, {
 321                .compatible = "atmel,at91sam9x5-rtc",
 322                .data = &at91sam9x5_config,
 323        }, {
 324                /* sentinel */
 325        }
 326};
 327MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
 328#endif
 329
 330static const struct at91_rtc_config *
 331at91_rtc_get_config(struct platform_device *pdev)
 332{
 333        const struct of_device_id *match;
 334
 335        if (pdev->dev.of_node) {
 336                match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
 337                if (!match)
 338                        return NULL;
 339                return (const struct at91_rtc_config *)match->data;
 340        }
 341
 342        return &at91rm9200_config;
 343}
 344
 345static const struct rtc_class_ops at91_rtc_ops = {
 346        .read_time      = at91_rtc_readtime,
 347        .set_time       = at91_rtc_settime,
 348        .read_alarm     = at91_rtc_readalarm,
 349        .set_alarm      = at91_rtc_setalarm,
 350        .proc           = at91_rtc_proc,
 351        .alarm_irq_enable = at91_rtc_alarm_irq_enable,
 352};
 353
 354/*
 355 * Initialize and install RTC driver
 356 */
 357static int __init at91_rtc_probe(struct platform_device *pdev)
 358{
 359        struct rtc_device *rtc;
 360        struct resource *regs;
 361        int ret = 0;
 362
 363        at91_rtc_config = at91_rtc_get_config(pdev);
 364        if (!at91_rtc_config)
 365                return -ENODEV;
 366
 367        regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 368        if (!regs) {
 369                dev_err(&pdev->dev, "no mmio resource defined\n");
 370                return -ENXIO;
 371        }
 372
 373        irq = platform_get_irq(pdev, 0);
 374        if (irq < 0) {
 375                dev_err(&pdev->dev, "no irq resource defined\n");
 376                return -ENXIO;
 377        }
 378
 379        at91_rtc_regs = ioremap(regs->start, resource_size(regs));
 380        if (!at91_rtc_regs) {
 381                dev_err(&pdev->dev, "failed to map registers, aborting.\n");
 382                return -ENOMEM;
 383        }
 384
 385        at91_rtc_write(AT91_RTC_CR, 0);
 386        at91_rtc_write(AT91_RTC_MR, 0);         /* 24 hour mode */
 387
 388        /* Disable all interrupts */
 389        at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 390                                        AT91_RTC_SECEV | AT91_RTC_TIMEV |
 391                                        AT91_RTC_CALEV);
 392
 393        ret = request_irq(irq, at91_rtc_interrupt,
 394                                IRQF_SHARED,
 395                                "at91_rtc", pdev);
 396        if (ret) {
 397                dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
 398                goto err_unmap;
 399        }
 400
 401        /* cpu init code should really have flagged this device as
 402         * being wake-capable; if it didn't, do that here.
 403         */
 404        if (!device_can_wakeup(&pdev->dev))
 405                device_init_wakeup(&pdev->dev, 1);
 406
 407        rtc = rtc_device_register(pdev->name, &pdev->dev,
 408                                &at91_rtc_ops, THIS_MODULE);
 409        if (IS_ERR(rtc)) {
 410                ret = PTR_ERR(rtc);
 411                goto err_free_irq;
 412        }
 413        platform_set_drvdata(pdev, rtc);
 414
 415        dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
 416        return 0;
 417
 418err_free_irq:
 419        free_irq(irq, pdev);
 420err_unmap:
 421        iounmap(at91_rtc_regs);
 422
 423        return ret;
 424}
 425
 426/*
 427 * Disable and remove the RTC driver
 428 */
 429static int __exit at91_rtc_remove(struct platform_device *pdev)
 430{
 431        struct rtc_device *rtc = platform_get_drvdata(pdev);
 432
 433        /* Disable all interrupts */
 434        at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 435                                        AT91_RTC_SECEV | AT91_RTC_TIMEV |
 436                                        AT91_RTC_CALEV);
 437        free_irq(irq, pdev);
 438
 439        rtc_device_unregister(rtc);
 440        iounmap(at91_rtc_regs);
 441
 442        return 0;
 443}
 444
 445#ifdef CONFIG_PM_SLEEP
 446
 447/* AT91RM9200 RTC Power management control */
 448
 449static u32 at91_rtc_imr;
 450
 451static int at91_rtc_suspend(struct device *dev)
 452{
 453        /* this IRQ is shared with DBGU and other hardware which isn't
 454         * necessarily doing PM like we are...
 455         */
 456        at91_rtc_imr = at91_rtc_read_imr()
 457                        & (AT91_RTC_ALARM|AT91_RTC_SECEV);
 458        if (at91_rtc_imr) {
 459                if (device_may_wakeup(dev))
 460                        enable_irq_wake(irq);
 461                else
 462                        at91_rtc_write_idr(at91_rtc_imr);
 463        }
 464        return 0;
 465}
 466
 467static int at91_rtc_resume(struct device *dev)
 468{
 469        if (at91_rtc_imr) {
 470                if (device_may_wakeup(dev))
 471                        disable_irq_wake(irq);
 472                else
 473                        at91_rtc_write_ier(at91_rtc_imr);
 474        }
 475        return 0;
 476}
 477#endif
 478
 479static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
 480
 481static struct platform_driver at91_rtc_driver = {
 482        .remove         = __exit_p(at91_rtc_remove),
 483        .driver         = {
 484                .name   = "at91_rtc",
 485                .owner  = THIS_MODULE,
 486                .pm     = &at91_rtc_pm_ops,
 487                .of_match_table = of_match_ptr(at91_rtc_dt_ids),
 488        },
 489};
 490
 491module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
 492
 493MODULE_AUTHOR("Rick Bronson");
 494MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
 495MODULE_LICENSE("GPL");
 496MODULE_ALIAS("platform:at91_rtc");
 497
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