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
  35#include <asm/uaccess.h>
  36
  37#include "rtc-at91rm9200.h"
  38
  39#define at91_rtc_read(field) \
  40        __raw_readl(at91_rtc_regs + field)
  41#define at91_rtc_write(field, val) \
  42        __raw_writel((val), at91_rtc_regs + field)
  43
  44#define AT91_RTC_EPOCH          1900UL  /* just like arch/arm/common/rtctime.c */
  45
  46struct at91_rtc_config {
  47        bool use_shadow_imr;
  48};
  49
  50static const struct at91_rtc_config *at91_rtc_config;
  51static DECLARE_COMPLETION(at91_rtc_updated);
  52static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
  53static void __iomem *at91_rtc_regs;
  54static int irq;
  55static DEFINE_SPINLOCK(at91_rtc_lock);
  56static u32 at91_rtc_shadow_imr;
  57
  58static void at91_rtc_write_ier(u32 mask)
  59{
  60        unsigned long flags;
  61
  62        spin_lock_irqsave(&at91_rtc_lock, flags);
  63        at91_rtc_shadow_imr |= mask;
  64        at91_rtc_write(AT91_RTC_IER, mask);
  65        spin_unlock_irqrestore(&at91_rtc_lock, flags);
  66}
  67
  68static void at91_rtc_write_idr(u32 mask)
  69{
  70        unsigned long flags;
  71
  72        spin_lock_irqsave(&at91_rtc_lock, flags);
  73        at91_rtc_write(AT91_RTC_IDR, mask);
  74        /*
  75         * Register read back (of any RTC-register) needed to make sure
  76         * IDR-register write has reached the peripheral before updating
  77         * shadow mask.
  78         *
  79         * Note that there is still a possibility that the mask is updated
  80         * before interrupts have actually been disabled in hardware. The only
  81         * way to be certain would be to poll the IMR-register, which is is
  82         * the very register we are trying to emulate. The register read back
  83         * is a reasonable heuristic.
  84         */
  85        at91_rtc_read(AT91_RTC_SR);
  86        at91_rtc_shadow_imr &= ~mask;
  87        spin_unlock_irqrestore(&at91_rtc_lock, flags);
  88}
  89
  90static u32 at91_rtc_read_imr(void)
  91{
  92        unsigned long flags;
  93        u32 mask;
  94
  95        if (at91_rtc_config->use_shadow_imr) {
  96                spin_lock_irqsave(&at91_rtc_lock, flags);
  97                mask = at91_rtc_shadow_imr;
  98                spin_unlock_irqrestore(&at91_rtc_lock, flags);
  99        } else {
 100                mask = at91_rtc_read(AT91_RTC_IMR);
 101        }
 102
 103        return mask;
 104}
 105
 106/*
 107 * Decode time/date into rtc_time structure
 108 */
 109static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
 110                                struct rtc_time *tm)
 111{
 112        unsigned int time, date;
 113
 114        /* must read twice in case it changes */
 115        do {
 116                time = at91_rtc_read(timereg);
 117                date = at91_rtc_read(calreg);
 118        } while ((time != at91_rtc_read(timereg)) ||
 119                        (date != at91_rtc_read(calreg)));
 120
 121        tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
 122        tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
 123        tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
 124
 125        /*
 126         * The Calendar Alarm register does not have a field for
 127         * the year - so these will return an invalid value.  When an
 128         * alarm is set, at91_alarm_year will store the current year.
 129         */
 130        tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;     /* century */
 131        tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);    /* year */
 132
 133        tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
 134        tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
 135        tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
 136}
 137
 138/*
 139 * Read current time and date in RTC
 140 */
 141static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
 142{
 143        at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
 144        tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 145        tm->tm_year = tm->tm_year - 1900;
 146
 147        dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 148                1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 149                tm->tm_hour, tm->tm_min, tm->tm_sec);
 150
 151        return 0;
 152}
 153
 154/*
 155 * Set current time and date in RTC
 156 */
 157static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
 158{
 159        unsigned long cr;
 160
 161        dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 162                1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 163                tm->tm_hour, tm->tm_min, tm->tm_sec);
 164
 165        /* Stop Time/Calendar from counting */
 166        cr = at91_rtc_read(AT91_RTC_CR);
 167        at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
 168
 169        at91_rtc_write_ier(AT91_RTC_ACKUPD);
 170        wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
 171        at91_rtc_write_idr(AT91_RTC_ACKUPD);
 172
 173        at91_rtc_write(AT91_RTC_TIMR,
 174                          bin2bcd(tm->tm_sec) << 0
 175                        | bin2bcd(tm->tm_min) << 8
 176                        | bin2bcd(tm->tm_hour) << 16);
 177
 178        at91_rtc_write(AT91_RTC_CALR,
 179                          bin2bcd((tm->tm_year + 1900) / 100)   /* century */
 180                        | bin2bcd(tm->tm_year % 100) << 8       /* year */
 181                        | bin2bcd(tm->tm_mon + 1) << 16         /* tm_mon starts at zero */
 182                        | bin2bcd(tm->tm_wday + 1) << 21        /* day of the week [0-6], Sunday=0 */
 183                        | bin2bcd(tm->tm_mday) << 24);
 184
 185        /* Restart Time/Calendar */
 186        cr = at91_rtc_read(AT91_RTC_CR);
 187        at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
 188
 189        return 0;
 190}
 191
 192/*
 193 * Read alarm time and date in RTC
 194 */
 195static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 196{
 197        struct rtc_time *tm = &alrm->time;
 198
 199        at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
 200        tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 201        tm->tm_year = at91_alarm_year - 1900;
 202
 203        alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
 204                        ? 1 : 0;
 205
 206        dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 207                1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 208                tm->tm_hour, tm->tm_min, tm->tm_sec);
 209
 210        return 0;
 211}
 212
 213/*
 214 * Set alarm time and date in RTC
 215 */
 216static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 217{
 218        struct rtc_time tm;
 219
 220        at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
 221
 222        at91_alarm_year = tm.tm_year;
 223
 224        tm.tm_hour = alrm->time.tm_hour;
 225        tm.tm_min = alrm->time.tm_min;
 226        tm.tm_sec = alrm->time.tm_sec;
 227
 228        at91_rtc_write_idr(AT91_RTC_ALARM);
 229        at91_rtc_write(AT91_RTC_TIMALR,
 230                  bin2bcd(tm.tm_sec) << 0
 231                | bin2bcd(tm.tm_min) << 8
 232                | bin2bcd(tm.tm_hour) << 16
 233                | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
 234        at91_rtc_write(AT91_RTC_CALALR,
 235                  bin2bcd(tm.tm_mon + 1) << 16          /* tm_mon starts at zero */
 236                | bin2bcd(tm.tm_mday) << 24
 237                | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
 238
 239        if (alrm->enabled) {
 240                at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 241                at91_rtc_write_ier(AT91_RTC_ALARM);
 242        }
 243
 244        dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 245                at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
 246                tm.tm_min, tm.tm_sec);
 247
 248        return 0;
 249}
 250
 251static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 252{
 253        dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
 254
 255        if (enabled) {
 256                at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 257                at91_rtc_write_ier(AT91_RTC_ALARM);
 258        } else
 259                at91_rtc_write_idr(AT91_RTC_ALARM);
 260
 261        return 0;
 262}
 263/*
 264 * Provide additional RTC information in /proc/driver/rtc
 265 */
 266static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
 267{
 268        unsigned long imr = at91_rtc_read_imr();
 269
 270        seq_printf(seq, "update_IRQ\t: %s\n",
 271                        (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
 272        seq_printf(seq, "periodic_IRQ\t: %s\n",
 273                        (imr & AT91_RTC_SECEV) ? "yes" : "no");
 274
 275        return 0;
 276}
 277
 278/*
 279 * IRQ handler for the RTC
 280 */
 281static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
 282{
 283        struct platform_device *pdev = dev_id;
 284        struct rtc_device *rtc = platform_get_drvdata(pdev);
 285        unsigned int rtsr;
 286        unsigned long events = 0;
 287
 288        rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
 289        if (rtsr) {             /* this interrupt is shared!  Is it ours? */
 290                if (rtsr & AT91_RTC_ALARM)
 291                        events |= (RTC_AF | RTC_IRQF);
 292                if (rtsr & AT91_RTC_SECEV)
 293                        events |= (RTC_UF | RTC_IRQF);
 294                if (rtsr & AT91_RTC_ACKUPD)
 295                        complete(&at91_rtc_updated);
 296
 297                at91_rtc_write(AT91_RTC_SCCR, rtsr);    /* clear status reg */
 298
 299                rtc_update_irq(rtc, 1, events);
 300
 301                dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", __func__,
 302                        events >> 8, events & 0x000000FF);
 303
 304                return IRQ_HANDLED;
 305        }
 306        return IRQ_NONE;                /* not handled */
 307}
 308
 309static const struct at91_rtc_config at91rm9200_config = {
 310};
 311
 312static const struct at91_rtc_config at91sam9x5_config = {
 313        .use_shadow_imr = true,
 314};
 315
 316#ifdef CONFIG_OF
 317static const struct of_device_id at91_rtc_dt_ids[] = {
 318        {
 319                .compatible = "atmel,at91rm9200-rtc",
 320                .data = &at91rm9200_config,
 321        }, {
 322                .compatible = "atmel,at91sam9x5-rtc",
 323                .data = &at91sam9x5_config,
 324        }, {
 325                /* sentinel */
 326        }
 327};
 328MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
 329#endif
 330
 331static const struct at91_rtc_config *
 332at91_rtc_get_config(struct platform_device *pdev)
 333{
 334        const struct of_device_id *match;
 335
 336        if (pdev->dev.of_node) {
 337                match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
 338                if (!match)
 339                        return NULL;
 340                return (const struct at91_rtc_config *)match->data;
 341        }
 342
 343        return &at91rm9200_config;
 344}
 345
 346static const struct rtc_class_ops at91_rtc_ops = {
 347        .read_time      = at91_rtc_readtime,
 348        .set_time       = at91_rtc_settime,
 349        .read_alarm     = at91_rtc_readalarm,
 350        .set_alarm      = at91_rtc_setalarm,
 351        .proc           = at91_rtc_proc,
 352        .alarm_irq_enable = at91_rtc_alarm_irq_enable,
 353};
 354
 355/*
 356 * Initialize and install RTC driver
 357 */
 358static int __init at91_rtc_probe(struct platform_device *pdev)
 359{
 360        struct rtc_device *rtc;
 361        struct resource *regs;
 362        int ret = 0;
 363
 364        at91_rtc_config = at91_rtc_get_config(pdev);
 365        if (!at91_rtc_config)
 366                return -ENODEV;
 367
 368        regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 369        if (!regs) {
 370                dev_err(&pdev->dev, "no mmio resource defined\n");
 371                return -ENXIO;
 372        }
 373
 374        irq = platform_get_irq(pdev, 0);
 375        if (irq < 0) {
 376                dev_err(&pdev->dev, "no irq resource defined\n");
 377                return -ENXIO;
 378        }
 379
 380        at91_rtc_regs = ioremap(regs->start, resource_size(regs));
 381        if (!at91_rtc_regs) {
 382                dev_err(&pdev->dev, "failed to map registers, aborting.\n");
 383                return -ENOMEM;
 384        }
 385
 386        at91_rtc_write(AT91_RTC_CR, 0);
 387        at91_rtc_write(AT91_RTC_MR, 0);         /* 24 hour mode */
 388
 389        /* Disable all interrupts */
 390        at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 391                                        AT91_RTC_SECEV | AT91_RTC_TIMEV |
 392                                        AT91_RTC_CALEV);
 393
 394        ret = request_irq(irq, at91_rtc_interrupt,
 395                                IRQF_SHARED,
 396                                "at91_rtc", pdev);
 397        if (ret) {
 398                dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
 399                goto err_unmap;
 400        }
 401
 402        /* cpu init code should really have flagged this device as
 403         * being wake-capable; if it didn't, do that here.
 404         */
 405        if (!device_can_wakeup(&pdev->dev))
 406                device_init_wakeup(&pdev->dev, 1);
 407
 408        rtc = rtc_device_register(pdev->name, &pdev->dev,
 409                                &at91_rtc_ops, THIS_MODULE);
 410        if (IS_ERR(rtc)) {
 411                ret = PTR_ERR(rtc);
 412                goto err_free_irq;
 413        }
 414        platform_set_drvdata(pdev, rtc);
 415
 416        dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
 417        return 0;
 418
 419err_free_irq:
 420        free_irq(irq, pdev);
 421err_unmap:
 422        iounmap(at91_rtc_regs);
 423
 424        return ret;
 425}
 426
 427/*
 428 * Disable and remove the RTC driver
 429 */
 430static int __exit at91_rtc_remove(struct platform_device *pdev)
 431{
 432        struct rtc_device *rtc = platform_get_drvdata(pdev);
 433
 434        /* Disable all interrupts */
 435        at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 436                                        AT91_RTC_SECEV | AT91_RTC_TIMEV |
 437                                        AT91_RTC_CALEV);
 438        free_irq(irq, pdev);
 439
 440        rtc_device_unregister(rtc);
 441        iounmap(at91_rtc_regs);
 442        platform_set_drvdata(pdev, NULL);
 443
 444        return 0;
 445}
 446
 447#ifdef CONFIG_PM_SLEEP
 448
 449/* AT91RM9200 RTC Power management control */
 450
 451static u32 at91_rtc_imr;
 452
 453static int at91_rtc_suspend(struct device *dev)
 454{
 455        /* this IRQ is shared with DBGU and other hardware which isn't
 456         * necessarily doing PM like we are...
 457         */
 458        at91_rtc_imr = at91_rtc_read_imr()
 459                        & (AT91_RTC_ALARM|AT91_RTC_SECEV);
 460        if (at91_rtc_imr) {
 461                if (device_may_wakeup(dev))
 462                        enable_irq_wake(irq);
 463                else
 464                        at91_rtc_write_idr(at91_rtc_imr);
 465        }
 466        return 0;
 467}
 468
 469static int at91_rtc_resume(struct device *dev)
 470{
 471        if (at91_rtc_imr) {
 472                if (device_may_wakeup(dev))
 473                        disable_irq_wake(irq);
 474                else
 475                        at91_rtc_write_ier(at91_rtc_imr);
 476        }
 477        return 0;
 478}
 479#endif
 480
 481static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
 482
 483static struct platform_driver at91_rtc_driver = {
 484        .remove         = __exit_p(at91_rtc_remove),
 485        .driver         = {
 486                .name   = "at91_rtc",
 487                .owner  = THIS_MODULE,
 488                .pm     = &at91_rtc_pm_ops,
 489                .of_match_table = of_match_ptr(at91_rtc_dt_ids),
 490        },
 491};
 492
 493module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
 494
 495MODULE_AUTHOR("Rick Bronson");
 496MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
 497MODULE_LICENSE("GPL");
 498MODULE_ALIAS("platform:at91_rtc");
 499
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