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 #include <asm/arch/at91_rtc.h>
  33
  34
  35 #define AT91_RTC_FREQ           1
  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 wille 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_hour = alrm->time.tm_hour;
 160         tm.tm_min = alrm->time.tm_min;
 161         tm.tm_sec = alrm->time.tm_sec;
 162
 163         at91_sys_write(AT91_RTC_IDR, AT91_RTC_ALARM);
 164         at91_sys_write(AT91_RTC_TIMALR,
 165                   BIN2BCD(tm.tm_sec) << 0
 166                 | BIN2BCD(tm.tm_min) << 8
 167                 | BIN2BCD(tm.tm_hour) << 16
 168                 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
 169         at91_sys_write(AT91_RTC_CALALR,
 170                   BIN2BCD(tm.tm_mon + 1) << 16          /* tm_mon starts at zero */
 171                 | BIN2BCD(tm.tm_mday) << 24
 172                 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
 173
 174         if (alrm->enabled) {
 175                 at91_sys_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 176                 at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM);
 177         }
 178
 179         pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 180                 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
 181                 tm.tm_min, tm.tm_sec);
 182
 183         return 0;
 184 }
 185
 186 /*
 187  * Handle commands from user-space
 188  */
 189 static int at91_rtc_ioctl(struct device *dev, unsigned int cmd,
 190                         unsigned long arg)
 191 {
 192         int ret = 0;
 193
 194         pr_debug("%s(): cmd=%08x, arg=%08lx.\n", __func__, cmd, arg);
 195
 196         /* important:  scrub old status before enabling IRQs */
 197         switch (cmd) {
 198         case RTC_AIE_OFF:       /* alarm off */
 199                 at91_sys_write(AT91_RTC_IDR, AT91_RTC_ALARM);
 200                 break;
 201         case RTC_AIE_ON:        /* alarm on */
 202                 at91_sys_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 203                 at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM);
 204                 break;
 205         case RTC_UIE_OFF:       /* update off */
 206                 at91_sys_write(AT91_RTC_IDR, AT91_RTC_SECEV);
 207                 break;
 208         case RTC_UIE_ON:        /* update on */
 209                 at91_sys_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
 210                 at91_sys_write(AT91_RTC_IER, AT91_RTC_SECEV);
 211                 break;
 212         default:
 213                 ret = -ENOIOCTLCMD;
 214                 break;
 215         }
 216
 217         return ret;
 218 }
 219
 220 /*
 221  * Provide additional RTC information in /proc/driver/rtc
 222  */
 223 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
 224 {
 225         unsigned long imr = at91_sys_read(AT91_RTC_IMR);
 226
 227         seq_printf(seq, "update_IRQ\t: %s\n",
 228                         (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
 229         seq_printf(seq, "periodic_IRQ\t: %s\n",
 230                         (imr & AT91_RTC_SECEV) ? "yes" : "no");
 231         seq_printf(seq, "periodic_freq\t: %ld\n",
 232                         (unsigned long) AT91_RTC_FREQ);
 233
 234         return 0;
 235 }
 236
 237 /*
 238  * IRQ handler for the RTC
 239  */
 240 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
 241 {
 242         struct platform_device *pdev = dev_id;
 243         struct rtc_device *rtc = platform_get_drvdata(pdev);
 244         unsigned int rtsr;
 245         unsigned long events = 0;
 246
 247         rtsr = at91_sys_read(AT91_RTC_SR) & at91_sys_read(AT91_RTC_IMR);
 248         if (rtsr) {             /* this interrupt is shared!  Is it ours? */
 249                 if (rtsr & AT91_RTC_ALARM)
 250                         events |= (RTC_AF | RTC_IRQF);
 251                 if (rtsr & AT91_RTC_SECEV)
 252                         events |= (RTC_UF | RTC_IRQF);
 253                 if (rtsr & AT91_RTC_ACKUPD)
 254                         complete(&at91_rtc_updated);
 255
 256                 at91_sys_write(AT91_RTC_SCCR, rtsr);    /* clear status reg */
 257
 258                 rtc_update_irq(rtc, 1, events);
 259
 260                 pr_debug("%s(): num=%ld, events=0x%02lx\n", __func__,
 261                         events >> 8, events & 0x000000FF);
 262
 263                 return IRQ_HANDLED;
 264         }
 265         return IRQ_NONE;                /* not handled */
 266 }
 267
 268 static const struct rtc_class_ops at91_rtc_ops = {
 269         .ioctl          = at91_rtc_ioctl,
 270         .read_time      = at91_rtc_readtime,
 271         .set_time       = at91_rtc_settime,
 272         .read_alarm     = at91_rtc_readalarm,
 273         .set_alarm      = at91_rtc_setalarm,
 274         .proc           = at91_rtc_proc,
 275 };
 276
 277 /*
 278  * Initialize and install RTC driver
 279  */
 280 static int __init at91_rtc_probe(struct platform_device *pdev)
 281 {
 282         struct rtc_device *rtc;
 283         int ret;
 284
 285         at91_sys_write(AT91_RTC_CR, 0);
 286         at91_sys_write(AT91_RTC_MR, 0);         /* 24 hour mode */
 287
 288         /* Disable all interrupts */
 289         at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 290                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 291                                         AT91_RTC_CALEV);
 292
 293         ret = request_irq(AT91_ID_SYS, at91_rtc_interrupt,
 294                                 IRQF_DISABLED | IRQF_SHARED,
 295                                 "at91_rtc", pdev);
 296         if (ret) {
 297                 printk(KERN_ERR "at91_rtc: IRQ %d already in use.\n",
 298                                 AT91_ID_SYS);
 299                 return ret;
 300         }
 301
 302         /* cpu init code should really have flagged this device as
 303          * being wake-capable; if it didn't, do that here.
 304          */
 305         if (!device_can_wakeup(&pdev->dev))
 306                 device_init_wakeup(&pdev->dev, 1);
 307
 308         rtc = rtc_device_register(pdev->name, &pdev->dev,
 309                                 &at91_rtc_ops, THIS_MODULE);
 310         if (IS_ERR(rtc)) {
 311                 free_irq(AT91_ID_SYS, pdev);
 312                 return PTR_ERR(rtc);
 313         }
 314         platform_set_drvdata(pdev, rtc);
 315
 316         printk(KERN_INFO "AT91 Real Time Clock driver.\n");
 317         return 0;
 318 }
 319
 320 /*
 321  * Disable and remove the RTC driver
 322  */
 323 static int __exit at91_rtc_remove(struct platform_device *pdev)
 324 {
 325         struct rtc_device *rtc = platform_get_drvdata(pdev);
 326
 327         /* Disable all interrupts */
 328         at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 329                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 330                                         AT91_RTC_CALEV);
 331         free_irq(AT91_ID_SYS, pdev);
 332
 333         rtc_device_unregister(rtc);
 334         platform_set_drvdata(pdev, NULL);
 335
 336         return 0;
 337 }
 338
 339 #ifdef CONFIG_PM
 340
 341 /* AT91RM9200 RTC Power management control */
 342
 343 static u32 at91_rtc_imr;
 344
 345 static int at91_rtc_suspend(struct platform_device *pdev, pm_message_t state)
 346 {
 347         /* this IRQ is shared with DBGU and other hardware which isn't
 348          * necessarily doing PM like we are...
 349          */
 350         at91_rtc_imr = at91_sys_read(AT91_RTC_IMR)
 351                         & (AT91_RTC_ALARM|AT91_RTC_SECEV);
 352         if (at91_rtc_imr) {
 353                 if (device_may_wakeup(&pdev->dev))
 354                         enable_irq_wake(AT91_ID_SYS);
 355                 else
 356                         at91_sys_write(AT91_RTC_IDR, at91_rtc_imr);
 357         }
 358         return 0;
 359 }
 360
 361 static int at91_rtc_resume(struct platform_device *pdev)
 362 {
 363         if (at91_rtc_imr) {
 364                 if (device_may_wakeup(&pdev->dev))
 365                         disable_irq_wake(AT91_ID_SYS);
 366                 else
 367                         at91_sys_write(AT91_RTC_IER, at91_rtc_imr);
 368         }
 369         return 0;
 370 }
 371 #else
 372 #define at91_rtc_suspend NULL
 373 #define at91_rtc_resume  NULL
 374 #endif
 375
 376 static struct platform_driver at91_rtc_driver = {
 377         .remove         = __exit_p(at91_rtc_remove),
 378         .suspend        = at91_rtc_suspend,
 379         .resume         = at91_rtc_resume,
 380         .driver         = {
 381                 .name   = "at91_rtc",
 382                 .owner  = THIS_MODULE,
 383         },
 384 };
 385
 386 static int __init at91_rtc_init(void)
 387 {
 388         return platform_driver_probe(&at91_rtc_driver, at91_rtc_probe);
 389 }
 390
 391 static void __exit at91_rtc_exit(void)
 392 {
 393         platform_driver_unregister(&at91_rtc_driver);
 394 }
 395
 396 module_init(at91_rtc_init);
 397 module_exit(at91_rtc_exit);
 398
 399 MODULE_AUTHOR("Rick Bronson");
 400 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
 401 MODULE_LICENSE("GPL");
 402 MODULE_ALIAS("platform:at91_rtc");