drivers/rtc/rtc-at91rm9200.c

   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
  31 #include <asm/uaccess.h>
  32
  33 #include <mach/at91_rtc.h>
  34
  35
  36 #define AT91_RTC_EPOCH          1900UL  /* just like arch/arm/common/rtctime.c */
  37
  38 static DECLARE_COMPLETION(at91_rtc_updated);
  39 static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
  40
  41 /*
  42  * Decode time/date into rtc_time structure
  43  */
  44 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
  45                                 struct rtc_time *tm)
  46 {
  47         unsigned int time, date;
  48
  49         /* must read twice in case it changes */
  50         do {
  51                 time = at91_sys_read(timereg);
  52                 date = at91_sys_read(calreg);
  53         } while ((time != at91_sys_read(timereg)) ||
  54                         (date != at91_sys_read(calreg)));
  55
  56         tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
  57         tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
  58         tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
  59
  60         /*
  61          * The Calendar Alarm register does not have a field for
  62          * the year - so these will return an invalid value.  When an
  63          * alarm is set, at91_alarm_year will store the current year.
  64          */
  65         tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;     /* century */
  66         tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);    /* year */
  67
  68         tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
  69         tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
  70         tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
  71 }
  72
  73 /*
  74  * Read current time and date in RTC
  75  */
  76 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
  77 {
  78         at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
  79         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
  80         tm->tm_year = tm->tm_year - 1900;
  81
  82         pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
  83                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
  84                 tm->tm_hour, tm->tm_min, tm->tm_sec);
  85
  86         return 0;
  87 }
  88
  89 /*
  90  * Set current time and date in RTC
  91  */
  92 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
  93 {
  94         unsigned long cr;
  95
  96         pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
  97                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
  98                 tm->tm_hour, tm->tm_min, tm->tm_sec);
  99
 100         /* Stop Time/Calendar from counting */
 101         cr = at91_sys_read(AT91_RTC_CR);
 102         at91_sys_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
 103
 104         at91_sys_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
 105         wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
 106         at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);
 107
 108         at91_sys_write(AT91_RTC_TIMR,
 109                           bin2bcd(tm->tm_sec) << 0
 110                         | bin2bcd(tm->tm_min) << 8
 111                         | bin2bcd(tm->tm_hour) << 16);
 112
 113         at91_sys_write(AT91_RTC_CALR,
 114                           bin2bcd((tm->tm_year + 1900) / 100)   /* century */
 115                         | bin2bcd(tm->tm_year % 100) << 8       /* year */
 116                         | bin2bcd(tm->tm_mon + 1) << 16         /* tm_mon starts at zero */
 117                         | bin2bcd(tm->tm_wday + 1) << 21        /* day of the week [0-6], Sunday=0 */
 118                         | bin2bcd(tm->tm_mday) << 24);
 119
 120         /* Restart Time/Calendar */
 121         cr = at91_sys_read(AT91_RTC_CR);
 122         at91_sys_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
 123
 124         return 0;
 125 }
 126
 127 /*
 128  * Read alarm time and date in RTC
 129  */
 130 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 131 {
 132         struct rtc_time *tm = &alrm->time;
 133
 134         at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
 135         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 136         tm->tm_year = at91_alarm_year - 1900;
 137
 138         alrm->enabled = (at91_sys_read(AT91_RTC_IMR) & AT91_RTC_ALARM)
 139                         ? 1 : 0;
 140
 141         pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 142                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 143                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 144
 145         return 0;
 146 }
 147
 148 /*
 149  * Set alarm time and date in RTC
 150  */
 151 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 152 {
 153         struct rtc_time tm;
 154
 155         at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
 156
 157         at91_alarm_year = tm.tm_year;
 158
 159         tm.tm_mon = alrm->time.tm_mon;
 160         tm.tm_mday = alrm->time.tm_mday;
 161         tm.tm_hour = alrm->time.tm_hour;
 162         tm.tm_min = alrm->time.tm_min;
 163         tm.tm_sec = alrm->time.tm_sec;
 164
 165         at91_sys_write(AT91_RTC_IDR, AT91_RTC_ALARM);
 166         at91_sys_write(AT91_RTC_TIMALR,
 167                   bin2bcd(tm.tm_sec) << 0
 168                 | bin2bcd(tm.tm_min) << 8
 169                 | bin2bcd(tm.tm_hour) << 16
 170                 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
 171         at91_sys_write(AT91_RTC_CALALR,
 172                   bin2bcd(tm.tm_mon + 1) << 16          /* tm_mon starts at zero */
 173                 | bin2bcd(tm.tm_mday) << 24
 174                 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
 175
 176         if (alrm->enabled) {
 177                 at91_sys_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 178                 at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM);
 179         }
 180
 181         pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 182                 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
 183                 tm.tm_min, tm.tm_sec);
 184
 185         return 0;
 186 }
 187
 188 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 189 {
 190         pr_debug("%s(): cmd=%08x\n", __func__, enabled);
 191
 192         if (enabled) {
 193                 at91_sys_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 194                 at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM);
 195         } else
 196                 at91_sys_write(AT91_RTC_IDR, AT91_RTC_ALARM);
 197
 198         return 0;
 199 }
 200 /*
 201  * Provide additional RTC information in /proc/driver/rtc
 202  */
 203 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
 204 {
 205         unsigned long imr = at91_sys_read(AT91_RTC_IMR);
 206
 207         seq_printf(seq, "update_IRQ\t: %s\n",
 208                         (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
 209         seq_printf(seq, "periodic_IRQ\t: %s\n",
 210                         (imr & AT91_RTC_SECEV) ? "yes" : "no");
 211
 212         return 0;
 213 }
 214
 215 /*
 216  * IRQ handler for the RTC
 217  */
 218 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
 219 {
 220         struct platform_device *pdev = dev_id;
 221         struct rtc_device *rtc = platform_get_drvdata(pdev);
 222         unsigned int rtsr;
 223         unsigned long events = 0;
 224
 225         rtsr = at91_sys_read(AT91_RTC_SR) & at91_sys_read(AT91_RTC_IMR);
 226         if (rtsr) {             /* this interrupt is shared!  Is it ours? */
 227                 if (rtsr & AT91_RTC_ALARM)
 228                         events |= (RTC_AF | RTC_IRQF);
 229                 if (rtsr & AT91_RTC_SECEV)
 230                         events |= (RTC_UF | RTC_IRQF);
 231                 if (rtsr & AT91_RTC_ACKUPD)
 232                         complete(&at91_rtc_updated);
 233
 234                 at91_sys_write(AT91_RTC_SCCR, rtsr);    /* clear status reg */
 235
 236                 rtc_update_irq(rtc, 1, events);
 237
 238                 pr_debug("%s(): num=%ld, events=0x%02lx\n", __func__,
 239                         events >> 8, events & 0x000000FF);
 240
 241                 return IRQ_HANDLED;
 242         }
 243         return IRQ_NONE;                /* not handled */
 244 }
 245
 246 static const struct rtc_class_ops at91_rtc_ops = {
 247         .read_time      = at91_rtc_readtime,
 248         .set_time       = at91_rtc_settime,
 249         .read_alarm     = at91_rtc_readalarm,
 250         .set_alarm      = at91_rtc_setalarm,
 251         .proc           = at91_rtc_proc,
 252         .alarm_irq_enable = at91_rtc_alarm_irq_enable,
 253 };
 254
 255 /*
 256  * Initialize and install RTC driver
 257  */
 258 static int __init at91_rtc_probe(struct platform_device *pdev)
 259 {
 260         struct rtc_device *rtc;
 261         int ret;
 262
 263         at91_sys_write(AT91_RTC_CR, 0);
 264         at91_sys_write(AT91_RTC_MR, 0);         /* 24 hour mode */
 265
 266         /* Disable all interrupts */
 267         at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 268                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 269                                         AT91_RTC_CALEV);
 270
 271         ret = request_irq(AT91_ID_SYS, at91_rtc_interrupt,
 272                                 IRQF_SHARED,
 273                                 "at91_rtc", pdev);
 274         if (ret) {
 275                 printk(KERN_ERR "at91_rtc: IRQ %d already in use.\n",
 276                                 AT91_ID_SYS);
 277                 return ret;
 278         }
 279
 280         /* cpu init code should really have flagged this device as
 281          * being wake-capable; if it didn't, do that here.
 282          */
 283         if (!device_can_wakeup(&pdev->dev))
 284                 device_init_wakeup(&pdev->dev, 1);
 285
 286         rtc = rtc_device_register(pdev->name, &pdev->dev,
 287                                 &at91_rtc_ops, THIS_MODULE);
 288         if (IS_ERR(rtc)) {
 289                 free_irq(AT91_ID_SYS, pdev);
 290                 return PTR_ERR(rtc);
 291         }
 292         platform_set_drvdata(pdev, rtc);
 293
 294         printk(KERN_INFO "AT91 Real Time Clock driver.\n");
 295         return 0;
 296 }
 297
 298 /*
 299  * Disable and remove the RTC driver
 300  */
 301 static int __exit at91_rtc_remove(struct platform_device *pdev)
 302 {
 303         struct rtc_device *rtc = platform_get_drvdata(pdev);
 304
 305         /* Disable all interrupts */
 306         at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 307                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 308                                         AT91_RTC_CALEV);
 309         free_irq(AT91_ID_SYS, pdev);
 310
 311         rtc_device_unregister(rtc);
 312         platform_set_drvdata(pdev, NULL);
 313
 314         return 0;
 315 }
 316
 317 #ifdef CONFIG_PM
 318
 319 /* AT91RM9200 RTC Power management control */
 320
 321 static u32 at91_rtc_imr;
 322
 323 static int at91_rtc_suspend(struct device *dev)
 324 {
 325         /* this IRQ is shared with DBGU and other hardware which isn't
 326          * necessarily doing PM like we are...
 327          */
 328         at91_rtc_imr = at91_sys_read(AT91_RTC_IMR)
 329                         & (AT91_RTC_ALARM|AT91_RTC_SECEV);
 330         if (at91_rtc_imr) {
 331                 if (device_may_wakeup(dev))
 332                         enable_irq_wake(AT91_ID_SYS);
 333                 else
 334                         at91_sys_write(AT91_RTC_IDR, at91_rtc_imr);
 335         }
 336         return 0;
 337 }
 338
 339 static int at91_rtc_resume(struct device *dev)
 340 {
 341         if (at91_rtc_imr) {
 342                 if (device_may_wakeup(dev))
 343                         disable_irq_wake(AT91_ID_SYS);
 344                 else
 345                         at91_sys_write(AT91_RTC_IER, at91_rtc_imr);
 346         }
 347         return 0;
 348 }
 349
 350 static const struct dev_pm_ops at91_rtc_pm = {
 351         .suspend =      at91_rtc_suspend,
 352         .resume =       at91_rtc_resume,
 353 };
 354
 355 #define at91_rtc_pm_ptr &at91_rtc_pm
 356
 357 #else
 358 #define at91_rtc_pm_ptr NULL
 359 #endif
 360
 361 static struct platform_driver at91_rtc_driver = {
 362         .remove         = __exit_p(at91_rtc_remove),
 363         .driver         = {
 364                 .name   = "at91_rtc",
 365                 .owner  = THIS_MODULE,
 366                 .pm     = at91_rtc_pm_ptr,
 367         },
 368 };
 369
 370 static int __init at91_rtc_init(void)
 371 {
 372         return platform_driver_probe(&at91_rtc_driver, at91_rtc_probe);
 373 }
 374
 375 static void __exit at91_rtc_exit(void)
 376 {
 377         platform_driver_unregister(&at91_rtc_driver);
 378 }
 379
 380 module_init(at91_rtc_init);
 381 module_exit(at91_rtc_exit);
 382
 383 MODULE_AUTHOR("Rick Bronson");
 384 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
 385 MODULE_LICENSE("GPL");
 386 MODULE_ALIAS("platform:at91_rtc");