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 <mach/at91_rtc.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;
  47
  48/*
  49 * Decode time/date into rtc_time structure
  50 */
  51static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
  52                                struct rtc_time *tm)
  53{
  54        unsigned int time, date;
  55
  56        /* must read twice in case it changes */
  57        do {
  58                time = at91_rtc_read(timereg);
  59                date = at91_rtc_read(calreg);
  60        } while ((time != at91_rtc_read(timereg)) ||
  61                        (date != at91_rtc_read(calreg)));
  62
  63        tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
  64        tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
  65        tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
  66
  67        /*
  68         * The Calendar Alarm register does not have a field for
  69         * the year - so these will return an invalid value.  When an
  70         * alarm is set, at91_alarm_year will store the current year.
  71         */
  72        tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;     /* century */
  73        tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);    /* year */
  74
  75        tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
  76        tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
  77        tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
  78}
  79
  80/*
  81 * Read current time and date in RTC
  82 */
  83static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
  84{
  85        at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
  86        tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
  87        tm->tm_year = tm->tm_year - 1900;
  88
  89        pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
  90                1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
  91                tm->tm_hour, tm->tm_min, tm->tm_sec);
  92
  93        return 0;
  94}
  95
  96/*
  97 * Set current time and date in RTC
  98 */
  99static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
 100{
 101        unsigned long cr;
 102
 103        pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 104                1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 105                tm->tm_hour, tm->tm_min, tm->tm_sec);
 106
 107        /* Stop Time/Calendar from counting */
 108        cr = at91_rtc_read(AT91_RTC_CR);
 109        at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
 110
 111        at91_rtc_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
 112        wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
 113        at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);
 114
 115        at91_rtc_write(AT91_RTC_TIMR,
 116                          bin2bcd(tm->tm_sec) << 0
 117                        | bin2bcd(tm->tm_min) << 8
 118                        | bin2bcd(tm->tm_hour) << 16);
 119
 120        at91_rtc_write(AT91_RTC_CALR,
 121                          bin2bcd((tm->tm_year + 1900) / 100)   /* century */
 122                        | bin2bcd(tm->tm_year % 100) << 8       /* year */
 123                        | bin2bcd(tm->tm_mon + 1) << 16         /* tm_mon starts at zero */
 124                        | bin2bcd(tm->tm_wday + 1) << 21        /* day of the week [0-6], Sunday=0 */
 125                        | bin2bcd(tm->tm_mday) << 24);
 126
 127        /* Restart Time/Calendar */
 128        cr = at91_rtc_read(AT91_RTC_CR);
 129        at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
 130
 131        return 0;
 132}
 133
 134/*
 135 * Read alarm time and date in RTC
 136 */
 137static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 138{
 139        struct rtc_time *tm = &alrm->time;
 140
 141        at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
 142        tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 143        tm->tm_year = at91_alarm_year - 1900;
 144
 145        alrm->enabled = (at91_rtc_read(AT91_RTC_IMR) & AT91_RTC_ALARM)
 146                        ? 1 : 0;
 147
 148        pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 149                1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 150                tm->tm_hour, tm->tm_min, tm->tm_sec);
 151
 152        return 0;
 153}
 154
 155/*
 156 * Set alarm time and date in RTC
 157 */
 158static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 159{
 160        struct rtc_time tm;
 161
 162        at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
 163
 164        at91_alarm_year = tm.tm_year;
 165
 166        tm.tm_hour = alrm->time.tm_hour;
 167        tm.tm_min = alrm->time.tm_min;
 168        tm.tm_sec = alrm->time.tm_sec;
 169
 170        at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
 171        at91_rtc_write(AT91_RTC_TIMALR,
 172                  bin2bcd(tm.tm_sec) << 0
 173                | bin2bcd(tm.tm_min) << 8
 174                | bin2bcd(tm.tm_hour) << 16
 175                | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
 176        at91_rtc_write(AT91_RTC_CALALR,
 177                  bin2bcd(tm.tm_mon + 1) << 16          /* tm_mon starts at zero */
 178                | bin2bcd(tm.tm_mday) << 24
 179                | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
 180
 181        if (alrm->enabled) {
 182                at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 183                at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
 184        }
 185
 186        pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 187                at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
 188                tm.tm_min, tm.tm_sec);
 189
 190        return 0;
 191}
 192
 193static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 194{
 195        pr_debug("%s(): cmd=%08x\n", __func__, enabled);
 196
 197        if (enabled) {
 198                at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 199                at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
 200        } else
 201                at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
 202
 203        return 0;
 204}
 205/*
 206 * Provide additional RTC information in /proc/driver/rtc
 207 */
 208static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
 209{
 210        unsigned long imr = at91_rtc_read(AT91_RTC_IMR);
 211
 212        seq_printf(seq, "update_IRQ\t: %s\n",
 213                        (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
 214        seq_printf(seq, "periodic_IRQ\t: %s\n",
 215                        (imr & AT91_RTC_SECEV) ? "yes" : "no");
 216
 217        return 0;
 218}
 219
 220/*
 221 * IRQ handler for the RTC
 222 */
 223static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
 224{
 225        struct platform_device *pdev = dev_id;
 226        struct rtc_device *rtc = platform_get_drvdata(pdev);
 227        unsigned int rtsr;
 228        unsigned long events = 0;
 229
 230        rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read(AT91_RTC_IMR);
 231        if (rtsr) {             /* this interrupt is shared!  Is it ours? */
 232                if (rtsr & AT91_RTC_ALARM)
 233                        events |= (RTC_AF | RTC_IRQF);
 234                if (rtsr & AT91_RTC_SECEV)
 235                        events |= (RTC_UF | RTC_IRQF);
 236                if (rtsr & AT91_RTC_ACKUPD)
 237                        complete(&at91_rtc_updated);
 238
 239                at91_rtc_write(AT91_RTC_SCCR, rtsr);    /* clear status reg */
 240
 241                rtc_update_irq(rtc, 1, events);
 242
 243                pr_debug("%s(): num=%ld, events=0x%02lx\n", __func__,
 244                        events >> 8, events & 0x000000FF);
 245
 246                return IRQ_HANDLED;
 247        }
 248        return IRQ_NONE;                /* not handled */
 249}
 250
 251static const struct rtc_class_ops at91_rtc_ops = {
 252        .read_time      = at91_rtc_readtime,
 253        .set_time       = at91_rtc_settime,
 254        .read_alarm     = at91_rtc_readalarm,
 255        .set_alarm      = at91_rtc_setalarm,
 256        .proc           = at91_rtc_proc,
 257        .alarm_irq_enable = at91_rtc_alarm_irq_enable,
 258};
 259
 260/*
 261 * Initialize and install RTC driver
 262 */
 263static int __init at91_rtc_probe(struct platform_device *pdev)
 264{
 265        struct rtc_device *rtc;
 266        struct resource *regs;
 267        int ret = 0;
 268
 269        regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 270        if (!regs) {
 271                dev_err(&pdev->dev, "no mmio resource defined\n");
 272                return -ENXIO;
 273        }
 274
 275        irq = platform_get_irq(pdev, 0);
 276        if (irq < 0) {
 277                dev_err(&pdev->dev, "no irq resource defined\n");
 278                return -ENXIO;
 279        }
 280
 281        at91_rtc_regs = ioremap(regs->start, resource_size(regs));
 282        if (!at91_rtc_regs) {
 283                dev_err(&pdev->dev, "failed to map registers, aborting.\n");
 284                return -ENOMEM;
 285        }
 286
 287        at91_rtc_write(AT91_RTC_CR, 0);
 288        at91_rtc_write(AT91_RTC_MR, 0);         /* 24 hour mode */
 289
 290        /* Disable all interrupts */
 291        at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 292                                        AT91_RTC_SECEV | AT91_RTC_TIMEV |
 293                                        AT91_RTC_CALEV);
 294
 295        ret = request_irq(irq, at91_rtc_interrupt,
 296                                IRQF_SHARED,
 297                                "at91_rtc", pdev);
 298        if (ret) {
 299                printk(KERN_ERR "at91_rtc: IRQ %d already in use.\n",
 300                                irq);
 301                return ret;
 302        }
 303
 304        /* cpu init code should really have flagged this device as
 305         * being wake-capable; if it didn't, do that here.
 306         */
 307        if (!device_can_wakeup(&pdev->dev))
 308                device_init_wakeup(&pdev->dev, 1);
 309
 310        rtc = rtc_device_register(pdev->name, &pdev->dev,
 311                                &at91_rtc_ops, THIS_MODULE);
 312        if (IS_ERR(rtc)) {
 313                free_irq(irq, pdev);
 314                return PTR_ERR(rtc);
 315        }
 316        platform_set_drvdata(pdev, rtc);
 317
 318        printk(KERN_INFO "AT91 Real Time Clock driver.\n");
 319        return 0;
 320}
 321
 322/*
 323 * Disable and remove the RTC driver
 324 */
 325static int __exit at91_rtc_remove(struct platform_device *pdev)
 326{
 327        struct rtc_device *rtc = platform_get_drvdata(pdev);
 328
 329        /* Disable all interrupts */
 330        at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 331                                        AT91_RTC_SECEV | AT91_RTC_TIMEV |
 332                                        AT91_RTC_CALEV);
 333        free_irq(irq, pdev);
 334
 335        rtc_device_unregister(rtc);
 336        platform_set_drvdata(pdev, NULL);
 337
 338        return 0;
 339}
 340
 341#ifdef CONFIG_PM
 342
 343/* AT91RM9200 RTC Power management control */
 344
 345static u32 at91_rtc_imr;
 346
 347static int at91_rtc_suspend(struct device *dev)
 348{
 349        /* this IRQ is shared with DBGU and other hardware which isn't
 350         * necessarily doing PM like we are...
 351         */
 352        at91_rtc_imr = at91_rtc_read(AT91_RTC_IMR)
 353                        & (AT91_RTC_ALARM|AT91_RTC_SECEV);
 354        if (at91_rtc_imr) {
 355                if (device_may_wakeup(dev))
 356                        enable_irq_wake(irq);
 357                else
 358                        at91_rtc_write(AT91_RTC_IDR, at91_rtc_imr);
 359        }
 360        return 0;
 361}
 362
 363static int at91_rtc_resume(struct device *dev)
 364{
 365        if (at91_rtc_imr) {
 366                if (device_may_wakeup(dev))
 367                        disable_irq_wake(irq);
 368                else
 369                        at91_rtc_write(AT91_RTC_IER, at91_rtc_imr);
 370        }
 371        return 0;
 372}
 373
 374static const struct dev_pm_ops at91_rtc_pm = {
 375        .suspend =      at91_rtc_suspend,
 376        .resume =       at91_rtc_resume,
 377};
 378
 379#define at91_rtc_pm_ptr &at91_rtc_pm
 380
 381#else
 382#define at91_rtc_pm_ptr NULL
 383#endif
 384
 385static struct platform_driver at91_rtc_driver = {
 386        .remove         = __exit_p(at91_rtc_remove),
 387        .driver         = {
 388                .name   = "at91_rtc",
 389                .owner  = THIS_MODULE,
 390                .pm     = at91_rtc_pm_ptr,
 391        },
 392};
 393
 394static int __init at91_rtc_init(void)
 395{
 396        return platform_driver_probe(&at91_rtc_driver, at91_rtc_probe);
 397}
 398
 399static void __exit at91_rtc_exit(void)
 400{
 401        platform_driver_unregister(&at91_rtc_driver);
 402}
 403
 404module_init(at91_rtc_init);
 405module_exit(at91_rtc_exit);
 406
 407MODULE_AUTHOR("Rick Bronson");
 408MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
 409MODULE_LICENSE("GPL");
 410MODULE_ALIAS("platform:at91_rtc");
 411
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