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/ioctl.h>
  29#include <linux/completion.h>
  30#include <linux/io.h>
  31
  32#include <asm/uaccess.h>
  33
  34#include "rtc-at91rm9200.h"
  35
  36#define at91_rtc_read(field) \
  37        __raw_readl(at91_rtc_regs + field)
  38#define at91_rtc_write(field, val) \
  39        __raw_writel((val), at91_rtc_regs + field)
  40
  41#define AT91_RTC_EPOCH          1900UL  /* just like arch/arm/common/rtctime.c */
  42
  43static DECLARE_COMPLETION(at91_rtc_updated);
  44static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
  45static void __iomem *at91_rtc_regs;
  46static int irq;
  47static u32 at91_rtc_imr;
  48
  49/*
  50 * Decode time/date into rtc_time structure
  51 */
  52static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
  53                                struct rtc_time *tm)
  54{
  55        unsigned int time, date;
  56
  57        /* must read twice in case it changes */
  58        do {
  59                time = at91_rtc_read(timereg);
  60                date = at91_rtc_read(calreg);
  61        } while ((time != at91_rtc_read(timereg)) ||
  62                        (date != at91_rtc_read(calreg)));
  63
  64        tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
  65        tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
  66        tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
  67
  68        /*
  69         * The Calendar Alarm register does not have a field for
  70         * the year - so these will return an invalid value.  When an
  71         * alarm is set, at91_alarm_year will store the current year.
  72         */
  73        tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;     /* century */
  74        tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);    /* year */
  75
  76        tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
  77        tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
  78        tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
  79}
  80
  81/*
  82 * Read current time and date in RTC
  83 */
  84static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
  85{
  86        at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
  87        tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
  88        tm->tm_year = tm->tm_year - 1900;
  89
  90        pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
  91                1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
  92                tm->tm_hour, tm->tm_min, tm->tm_sec);
  93
  94        return 0;
  95}
  96
  97/*
  98 * Set current time and date in RTC
  99 */
 100static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
 101{
 102        unsigned long cr;
 103
 104        pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 105                1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 106                tm->tm_hour, tm->tm_min, tm->tm_sec);
 107
 108        /* Stop Time/Calendar from counting */
 109        cr = at91_rtc_read(AT91_RTC_CR);
 110        at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
 111
 112        at91_rtc_imr |= AT91_RTC_ACKUPD;
 113        at91_rtc_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
 114        wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
 115        at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);
 116        at91_rtc_imr &= ~AT91_RTC_ACKUPD;
 117
 118        at91_rtc_write(AT91_RTC_TIMR,
 119                          bin2bcd(tm->tm_sec) << 0
 120                        | bin2bcd(tm->tm_min) << 8
 121                        | bin2bcd(tm->tm_hour) << 16);
 122
 123        at91_rtc_write(AT91_RTC_CALR,
 124                          bin2bcd((tm->tm_year + 1900) / 100)   /* century */
 125                        | bin2bcd(tm->tm_year % 100) << 8       /* year */
 126                        | bin2bcd(tm->tm_mon + 1) << 16         /* tm_mon starts at zero */
 127                        | bin2bcd(tm->tm_wday + 1) << 21        /* day of the week [0-6], Sunday=0 */
 128                        | bin2bcd(tm->tm_mday) << 24);
 129
 130        /* Restart Time/Calendar */
 131        cr = at91_rtc_read(AT91_RTC_CR);
 132        at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
 133
 134        return 0;
 135}
 136
 137/*
 138 * Read alarm time and date in RTC
 139 */
 140static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 141{
 142        struct rtc_time *tm = &alrm->time;
 143
 144        at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
 145        tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 146        tm->tm_year = at91_alarm_year - 1900;
 147
 148        alrm->enabled = (at91_rtc_imr & AT91_RTC_ALARM)
 149                        ? 1 : 0;
 150
 151        pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 152                1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 153                tm->tm_hour, tm->tm_min, tm->tm_sec);
 154
 155        return 0;
 156}
 157
 158/*
 159 * Set alarm time and date in RTC
 160 */
 161static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 162{
 163        struct rtc_time tm;
 164
 165        at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
 166
 167        at91_alarm_year = tm.tm_year;
 168
 169        tm.tm_hour = alrm->time.tm_hour;
 170        tm.tm_min = alrm->time.tm_min;
 171        tm.tm_sec = alrm->time.tm_sec;
 172
 173        at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
 174        at91_rtc_imr &= ~AT91_RTC_ALARM;
 175        at91_rtc_write(AT91_RTC_TIMALR,
 176                  bin2bcd(tm.tm_sec) << 0
 177                | bin2bcd(tm.tm_min) << 8
 178                | bin2bcd(tm.tm_hour) << 16
 179                | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
 180        at91_rtc_write(AT91_RTC_CALALR,
 181                  bin2bcd(tm.tm_mon + 1) << 16          /* tm_mon starts at zero */
 182                | bin2bcd(tm.tm_mday) << 24
 183                | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
 184
 185        if (alrm->enabled) {
 186                at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 187                at91_rtc_imr |= AT91_RTC_ALARM;
 188                at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
 189        }
 190
 191        pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 192                at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
 193                tm.tm_min, tm.tm_sec);
 194
 195        return 0;
 196}
 197
 198static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 199{
 200        pr_debug("%s(): cmd=%08x\n", __func__, enabled);
 201
 202        if (enabled) {
 203                at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 204                at91_rtc_imr |= AT91_RTC_ALARM;
 205                at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
 206        } else {
 207                at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
 208                at91_rtc_imr &= ~AT91_RTC_ALARM;
 209        }
 210
 211        return 0;
 212}
 213/*
 214 * Provide additional RTC information in /proc/driver/rtc
 215 */
 216static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
 217{
 218        seq_printf(seq, "update_IRQ\t: %s\n",
 219                        (at91_rtc_imr & AT91_RTC_ACKUPD) ? "yes" : "no");
 220        seq_printf(seq, "periodic_IRQ\t: %s\n",
 221                        (at91_rtc_imr & AT91_RTC_SECEV) ? "yes" : "no");
 222
 223        return 0;
 224}
 225
 226/*
 227 * IRQ handler for the RTC
 228 */
 229static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
 230{
 231        struct platform_device *pdev = dev_id;
 232        struct rtc_device *rtc = platform_get_drvdata(pdev);
 233        unsigned int rtsr;
 234        unsigned long events = 0;
 235
 236        rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_imr;
 237        if (rtsr) {             /* this interrupt is shared!  Is it ours? */
 238                if (rtsr & AT91_RTC_ALARM)
 239                        events |= (RTC_AF | RTC_IRQF);
 240                if (rtsr & AT91_RTC_SECEV)
 241                        events |= (RTC_UF | RTC_IRQF);
 242                if (rtsr & AT91_RTC_ACKUPD)
 243                        complete(&at91_rtc_updated);
 244
 245                at91_rtc_write(AT91_RTC_SCCR, rtsr);    /* clear status reg */
 246
 247                rtc_update_irq(rtc, 1, events);
 248
 249                pr_debug("%s(): num=%ld, events=0x%02lx\n", __func__,
 250                        events >> 8, events & 0x000000FF);
 251
 252                return IRQ_HANDLED;
 253        }
 254        return IRQ_NONE;                /* not handled */
 255}
 256
 257static const struct rtc_class_ops at91_rtc_ops = {
 258        .read_time      = at91_rtc_readtime,
 259        .set_time       = at91_rtc_settime,
 260        .read_alarm     = at91_rtc_readalarm,
 261        .set_alarm      = at91_rtc_setalarm,
 262        .proc           = at91_rtc_proc,
 263        .alarm_irq_enable = at91_rtc_alarm_irq_enable,
 264};
 265
 266/*
 267 * Initialize and install RTC driver
 268 */
 269static int __init at91_rtc_probe(struct platform_device *pdev)
 270{
 271        struct rtc_device *rtc;
 272        struct resource *regs;
 273        int ret = 0;
 274
 275        regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 276        if (!regs) {
 277                dev_err(&pdev->dev, "no mmio resource defined\n");
 278                return -ENXIO;
 279        }
 280
 281        irq = platform_get_irq(pdev, 0);
 282        if (irq < 0) {
 283                dev_err(&pdev->dev, "no irq resource defined\n");
 284                return -ENXIO;
 285        }
 286
 287        at91_rtc_regs = ioremap(regs->start, resource_size(regs));
 288        if (!at91_rtc_regs) {
 289                dev_err(&pdev->dev, "failed to map registers, aborting.\n");
 290                return -ENOMEM;
 291        }
 292
 293        at91_rtc_write(AT91_RTC_CR, 0);
 294        at91_rtc_write(AT91_RTC_MR, 0);         /* 24 hour mode */
 295
 296        /* Disable all interrupts */
 297        at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 298                                        AT91_RTC_SECEV | AT91_RTC_TIMEV |
 299                                        AT91_RTC_CALEV);
 300        at91_rtc_imr = 0;
 301
 302        ret = request_irq(irq, at91_rtc_interrupt,
 303                                IRQF_SHARED,
 304                                "at91_rtc", pdev);
 305        if (ret) {
 306                printk(KERN_ERR "at91_rtc: IRQ %d already in use.\n",
 307                                irq);
 308                return ret;
 309        }
 310
 311        /* cpu init code should really have flagged this device as
 312         * being wake-capable; if it didn't, do that here.
 313         */
 314        if (!device_can_wakeup(&pdev->dev))
 315                device_init_wakeup(&pdev->dev, 1);
 316
 317        rtc = rtc_device_register(pdev->name, &pdev->dev,
 318                                &at91_rtc_ops, THIS_MODULE);
 319        if (IS_ERR(rtc)) {
 320                free_irq(irq, pdev);
 321                return PTR_ERR(rtc);
 322        }
 323        platform_set_drvdata(pdev, rtc);
 324
 325        printk(KERN_INFO "AT91 Real Time Clock driver.\n");
 326        return 0;
 327}
 328
 329/*
 330 * Disable and remove the RTC driver
 331 */
 332static int __exit at91_rtc_remove(struct platform_device *pdev)
 333{
 334        struct rtc_device *rtc = platform_get_drvdata(pdev);
 335
 336        /* Disable all interrupts */
 337        at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 338                                        AT91_RTC_SECEV | AT91_RTC_TIMEV |
 339                                        AT91_RTC_CALEV);
 340        at91_rtc_imr = 0;
 341        free_irq(irq, pdev);
 342
 343        rtc_device_unregister(rtc);
 344        platform_set_drvdata(pdev, NULL);
 345
 346        return 0;
 347}
 348
 349#ifdef CONFIG_PM
 350
 351/* AT91RM9200 RTC Power management control */
 352
 353static u32 at91_rtc_bkpimr;
 354
 355
 356static int at91_rtc_suspend(struct device *dev)
 357{
 358        /* this IRQ is shared with DBGU and other hardware which isn't
 359         * necessarily doing PM like we are...
 360         */
 361        at91_rtc_bkpimr = at91_rtc_imr & (AT91_RTC_ALARM|AT91_RTC_SECEV);
 362        if (at91_rtc_bkpimr) {
 363                if (device_may_wakeup(dev)) {
 364                        enable_irq_wake(irq);
 365                } else {
 366                        at91_rtc_write(AT91_RTC_IDR, at91_rtc_bkpimr);
 367                        at91_rtc_imr &= ~at91_rtc_bkpimr;
 368                }
 369}
 370        return 0;
 371}
 372
 373static int at91_rtc_resume(struct device *dev)
 374{
 375        if (at91_rtc_bkpimr) {
 376                if (device_may_wakeup(dev)) {
 377                        disable_irq_wake(irq);
 378                } else {
 379                        at91_rtc_imr |= at91_rtc_bkpimr;
 380                        at91_rtc_write(AT91_RTC_IER, at91_rtc_bkpimr);
 381                }
 382        }
 383        return 0;
 384}
 385
 386static const struct dev_pm_ops at91_rtc_pm = {
 387        .suspend =      at91_rtc_suspend,
 388        .resume =       at91_rtc_resume,
 389};
 390
 391#define at91_rtc_pm_ptr &at91_rtc_pm
 392
 393#else
 394#define at91_rtc_pm_ptr NULL
 395#endif
 396
 397static struct platform_driver at91_rtc_driver = {
 398        .remove         = __exit_p(at91_rtc_remove),
 399        .driver         = {
 400                .name   = "at91_rtc",
 401                .owner  = THIS_MODULE,
 402                .pm     = at91_rtc_pm_ptr,
 403        },
 404};
 405
 406static int __init at91_rtc_init(void)
 407{
 408        return platform_driver_probe(&at91_rtc_driver, at91_rtc_probe);
 409}
 410
 411static void __exit at91_rtc_exit(void)
 412{
 413        platform_driver_unregister(&at91_rtc_driver);
 414}
 415
 416module_init(at91_rtc_init);
 417module_exit(at91_rtc_exit);
 418
 419MODULE_AUTHOR("Rick Bronson");
 420MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
 421MODULE_LICENSE("GPL");
 422MODULE_ALIAS("platform:at91_rtc");
 423
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