drivers/rtc/rtc-sa1100.c

   1 /*
   2  * Real Time Clock interface for StrongARM SA1x00 and XScale PXA2xx
   3  *
   4  * Copyright (c) 2000 Nils Faerber
   5  *
   6  * Based on rtc.c by Paul Gortmaker
   7  *
   8  * Original Driver by Nils Faerber <nils@kernelconcepts.de>
   9  *
  10  * Modifications from:
  11  *   CIH <cih@coventive.com>
  12  *   Nicolas Pitre <nico@cam.org>
  13  *   Andrew Christian <andrew.christian@hp.com>
  14  *
  15  * Converted to the RTC subsystem and Driver Model
  16  *   by Richard Purdie <rpurdie@rpsys.net>
  17  *
  18  * This program is free software; you can redistribute it and/or
  19  * modify it under the terms of the GNU General Public License
  20  * as published by the Free Software Foundation; either version
  21  * 2 of the License, or (at your option) any later version.
  22  */
  23
  24 #include <linux/platform_device.h>
  25 #include <linux/module.h>
  26 #include <linux/rtc.h>
  27 #include <linux/init.h>
  28 #include <linux/fs.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/string.h>
  31 #include <linux/pm.h>
  32 #include <linux/bitops.h>
  33
  34 #include <mach/hardware.h>
  35 #include <asm/irq.h>
  36
  37 #ifdef CONFIG_ARCH_PXA
  38 #include <mach/regs-rtc.h>
  39 #include <mach/regs-ost.h>
  40 #endif
  41
  42 #define RTC_DEF_DIVIDER         32768 - 1
  43 #define RTC_DEF_TRIM            0
  44
  45 static unsigned long rtc_freq = 1024;
  46 static unsigned long timer_freq;
  47 static struct rtc_time rtc_alarm;
  48 static DEFINE_SPINLOCK(sa1100_rtc_lock);
  49
  50 static inline int rtc_periodic_alarm(struct rtc_time *tm)
  51 {
  52         return  (tm->tm_year == -1) ||
  53                 ((unsigned)tm->tm_mon >= 12) ||
  54                 ((unsigned)(tm->tm_mday - 1) >= 31) ||
  55                 ((unsigned)tm->tm_hour > 23) ||
  56                 ((unsigned)tm->tm_min > 59) ||
  57                 ((unsigned)tm->tm_sec > 59);
  58 }
  59
  60 /*
  61  * Calculate the next alarm time given the requested alarm time mask
  62  * and the current time.
  63  */
  64 static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now, struct rtc_time *alrm)
  65 {
  66         unsigned long next_time;
  67         unsigned long now_time;
  68
  69         next->tm_year = now->tm_year;
  70         next->tm_mon = now->tm_mon;
  71         next->tm_mday = now->tm_mday;
  72         next->tm_hour = alrm->tm_hour;
  73         next->tm_min = alrm->tm_min;
  74         next->tm_sec = alrm->tm_sec;
  75
  76         rtc_tm_to_time(now, &now_time);
  77         rtc_tm_to_time(next, &next_time);
  78
  79         if (next_time < now_time) {
  80                 /* Advance one day */
  81                 next_time += 60 * 60 * 24;
  82                 rtc_time_to_tm(next_time, next);
  83         }
  84 }
  85
  86 static int rtc_update_alarm(struct rtc_time *alrm)
  87 {
  88         struct rtc_time alarm_tm, now_tm;
  89         unsigned long now, time;
  90         int ret;
  91
  92         do {
  93                 now = RCNR;
  94                 rtc_time_to_tm(now, &now_tm);
  95                 rtc_next_alarm_time(&alarm_tm, &now_tm, alrm);
  96                 ret = rtc_tm_to_time(&alarm_tm, &time);
  97                 if (ret != 0)
  98                         break;
  99
 100                 RTSR = RTSR & (RTSR_HZE|RTSR_ALE|RTSR_AL);
 101                 RTAR = time;
 102         } while (now != RCNR);
 103
 104         return ret;
 105 }
 106
 107 static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id)
 108 {
 109         struct platform_device *pdev = to_platform_device(dev_id);
 110         struct rtc_device *rtc = platform_get_drvdata(pdev);
 111         unsigned int rtsr;
 112         unsigned long events = 0;
 113
 114         spin_lock(&sa1100_rtc_lock);
 115
 116         rtsr = RTSR;
 117         /* clear interrupt sources */
 118         RTSR = 0;
 119         RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2);
 120
 121         /* clear alarm interrupt if it has occurred */
 122         if (rtsr & RTSR_AL)
 123                 rtsr &= ~RTSR_ALE;
 124         RTSR = rtsr & (RTSR_ALE | RTSR_HZE);
 125
 126         /* update irq data & counter */
 127         if (rtsr & RTSR_AL)
 128                 events |= RTC_AF | RTC_IRQF;
 129         if (rtsr & RTSR_HZ)
 130                 events |= RTC_UF | RTC_IRQF;
 131
 132         rtc_update_irq(rtc, 1, events);
 133
 134         if (rtsr & RTSR_AL && rtc_periodic_alarm(&rtc_alarm))
 135                 rtc_update_alarm(&rtc_alarm);
 136
 137         spin_unlock(&sa1100_rtc_lock);
 138
 139         return IRQ_HANDLED;
 140 }
 141
 142 static int rtc_timer1_count;
 143
 144 static irqreturn_t timer1_interrupt(int irq, void *dev_id)
 145 {
 146         struct platform_device *pdev = to_platform_device(dev_id);
 147         struct rtc_device *rtc = platform_get_drvdata(pdev);
 148
 149         /*
 150          * If we match for the first time, rtc_timer1_count will be 1.
 151          * Otherwise, we wrapped around (very unlikely but
 152          * still possible) so compute the amount of missed periods.
 153          * The match reg is updated only when the data is actually retrieved
 154          * to avoid unnecessary interrupts.
 155          */
 156         OSSR = OSSR_M1; /* clear match on timer1 */
 157
 158         rtc_update_irq(rtc, rtc_timer1_count, RTC_PF | RTC_IRQF);
 159
 160         if (rtc_timer1_count == 1)
 161                 rtc_timer1_count = (rtc_freq * ((1 << 30) / (timer_freq >> 2)));
 162
 163         return IRQ_HANDLED;
 164 }
 165
 166 static int sa1100_rtc_read_callback(struct device *dev, int data)
 167 {
 168         if (data & RTC_PF) {
 169                 /* interpolate missed periods and set match for the next */
 170                 unsigned long period = timer_freq / rtc_freq;
 171                 unsigned long oscr = OSCR;
 172                 unsigned long osmr1 = OSMR1;
 173                 unsigned long missed = (oscr - osmr1)/period;
 174                 data += missed << 8;
 175                 OSSR = OSSR_M1; /* clear match on timer 1 */
 176                 OSMR1 = osmr1 + (missed + 1)*period;
 177                 /* Ensure we didn't miss another match in the mean time.
 178                  * Here we compare (match - OSCR) 8 instead of 0 --
 179                  * see comment in pxa_timer_interrupt() for explanation.
 180                  */
 181                 while( (signed long)((osmr1 = OSMR1) - OSCR) <= 8 ) {
 182                         data += 0x100;
 183                         OSSR = OSSR_M1; /* clear match on timer 1 */
 184                         OSMR1 = osmr1 + period;
 185                 }
 186         }
 187         return data;
 188 }
 189
 190 static int sa1100_rtc_open(struct device *dev)
 191 {
 192         int ret;
 193
 194         ret = request_irq(IRQ_RTC1Hz, sa1100_rtc_interrupt, IRQF_DISABLED,
 195                                 "rtc 1Hz", dev);
 196         if (ret) {
 197                 dev_err(dev, "IRQ %d already in use.\n", IRQ_RTC1Hz);
 198                 goto fail_ui;
 199         }
 200         ret = request_irq(IRQ_RTCAlrm, sa1100_rtc_interrupt, IRQF_DISABLED,
 201                                 "rtc Alrm", dev);
 202         if (ret) {
 203                 dev_err(dev, "IRQ %d already in use.\n", IRQ_RTCAlrm);
 204                 goto fail_ai;
 205         }
 206         ret = request_irq(IRQ_OST1, timer1_interrupt, IRQF_DISABLED,
 207                                 "rtc timer", dev);
 208         if (ret) {
 209                 dev_err(dev, "IRQ %d already in use.\n", IRQ_OST1);
 210                 goto fail_pi;
 211         }
 212         return 0;
 213
 214  fail_pi:
 215         free_irq(IRQ_RTCAlrm, dev);
 216  fail_ai:
 217         free_irq(IRQ_RTC1Hz, dev);
 218  fail_ui:
 219         return ret;
 220 }
 221
 222 static void sa1100_rtc_release(struct device *dev)
 223 {
 224         spin_lock_irq(&sa1100_rtc_lock);
 225         RTSR = 0;
 226         OIER &= ~OIER_E1;
 227         OSSR = OSSR_M1;
 228         spin_unlock_irq(&sa1100_rtc_lock);
 229
 230         free_irq(IRQ_OST1, dev);
 231         free_irq(IRQ_RTCAlrm, dev);
 232         free_irq(IRQ_RTC1Hz, dev);
 233 }
 234
 235
 236 static int sa1100_rtc_ioctl(struct device *dev, unsigned int cmd,
 237                 unsigned long arg)
 238 {
 239         switch(cmd) {
 240         case RTC_AIE_OFF:
 241                 spin_lock_irq(&sa1100_rtc_lock);
 242                 RTSR &= ~RTSR_ALE;
 243                 spin_unlock_irq(&sa1100_rtc_lock);
 244                 return 0;
 245         case RTC_AIE_ON:
 246                 spin_lock_irq(&sa1100_rtc_lock);
 247                 RTSR |= RTSR_ALE;
 248                 spin_unlock_irq(&sa1100_rtc_lock);
 249                 return 0;
 250         case RTC_UIE_OFF:
 251                 spin_lock_irq(&sa1100_rtc_lock);
 252                 RTSR &= ~RTSR_HZE;
 253                 spin_unlock_irq(&sa1100_rtc_lock);
 254                 return 0;
 255         case RTC_UIE_ON:
 256                 spin_lock_irq(&sa1100_rtc_lock);
 257                 RTSR |= RTSR_HZE;
 258                 spin_unlock_irq(&sa1100_rtc_lock);
 259                 return 0;
 260         case RTC_PIE_OFF:
 261                 spin_lock_irq(&sa1100_rtc_lock);
 262                 OIER &= ~OIER_E1;
 263                 spin_unlock_irq(&sa1100_rtc_lock);
 264                 return 0;
 265         case RTC_PIE_ON:
 266                 spin_lock_irq(&sa1100_rtc_lock);
 267                 OSMR1 = timer_freq / rtc_freq + OSCR;
 268                 OIER |= OIER_E1;
 269                 rtc_timer1_count = 1;
 270                 spin_unlock_irq(&sa1100_rtc_lock);
 271                 return 0;
 272         case RTC_IRQP_READ:
 273                 return put_user(rtc_freq, (unsigned long *)arg);
 274         case RTC_IRQP_SET:
 275                 if (arg < 1 || arg > timer_freq)
 276                         return -EINVAL;
 277                 rtc_freq = arg;
 278                 return 0;
 279         }
 280         return -ENOIOCTLCMD;
 281 }
 282
 283 static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm)
 284 {
 285         rtc_time_to_tm(RCNR, tm);
 286         return 0;
 287 }
 288
 289 static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm)
 290 {
 291         unsigned long time;
 292         int ret;
 293
 294         ret = rtc_tm_to_time(tm, &time);
 295         if (ret == 0)
 296                 RCNR = time;
 297         return ret;
 298 }
 299
 300 static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 301 {
 302         u32     rtsr;
 303
 304         memcpy(&alrm->time, &rtc_alarm, sizeof(struct rtc_time));
 305         rtsr = RTSR;
 306         alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0;
 307         alrm->pending = (rtsr & RTSR_AL) ? 1 : 0;
 308         return 0;
 309 }
 310
 311 static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 312 {
 313         int ret;
 314
 315         spin_lock_irq(&sa1100_rtc_lock);
 316         ret = rtc_update_alarm(&alrm->time);
 317         if (ret == 0) {
 318                 if (alrm->enabled)
 319                         RTSR |= RTSR_ALE;
 320                 else
 321                         RTSR &= ~RTSR_ALE;
 322         }
 323         spin_unlock_irq(&sa1100_rtc_lock);
 324
 325         return ret;
 326 }
 327
 328 static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq)
 329 {
 330         seq_printf(seq, "trim/divider\t: 0x%08x\n", (u32) RTTR);
 331         seq_printf(seq, "update_IRQ\t: %s\n",
 332                         (RTSR & RTSR_HZE) ? "yes" : "no");
 333         seq_printf(seq, "periodic_IRQ\t: %s\n",
 334                         (OIER & OIER_E1) ? "yes" : "no");
 335         seq_printf(seq, "periodic_freq\t: %ld\n", rtc_freq);
 336
 337         return 0;
 338 }
 339
 340 static const struct rtc_class_ops sa1100_rtc_ops = {
 341         .open = sa1100_rtc_open,
 342         .read_callback = sa1100_rtc_read_callback,
 343         .release = sa1100_rtc_release,
 344         .ioctl = sa1100_rtc_ioctl,
 345         .read_time = sa1100_rtc_read_time,
 346         .set_time = sa1100_rtc_set_time,
 347         .read_alarm = sa1100_rtc_read_alarm,
 348         .set_alarm = sa1100_rtc_set_alarm,
 349         .proc = sa1100_rtc_proc,
 350 };
 351
 352 static int sa1100_rtc_probe(struct platform_device *pdev)
 353 {
 354         struct rtc_device *rtc;
 355
 356         timer_freq = get_clock_tick_rate();
 357
 358         /*
 359          * According to the manual we should be able to let RTTR be zero
 360          * and then a default diviser for a 32.768KHz clock is used.
 361          * Apparently this doesn't work, at least for my SA1110 rev 5.
 362          * If the clock divider is uninitialized then reset it to the
 363          * default value to get the 1Hz clock.
 364          */
 365         if (RTTR == 0) {
 366                 RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16);
 367                 dev_warn(&pdev->dev, "warning: initializing default clock divider/trim value\n");
 368                 /* The current RTC value probably doesn't make sense either */
 369                 RCNR = 0;
 370         }
 371
 372         device_init_wakeup(&pdev->dev, 1);
 373
 374         rtc = rtc_device_register(pdev->name, &pdev->dev, &sa1100_rtc_ops,
 375                                 THIS_MODULE);
 376
 377         if (IS_ERR(rtc))
 378                 return PTR_ERR(rtc);
 379
 380         platform_set_drvdata(pdev, rtc);
 381
 382         return 0;
 383 }
 384
 385 static int sa1100_rtc_remove(struct platform_device *pdev)
 386 {
 387         struct rtc_device *rtc = platform_get_drvdata(pdev);
 388
 389         if (rtc)
 390                 rtc_device_unregister(rtc);
 391
 392         return 0;
 393 }
 394
 395 #ifdef CONFIG_PM
 396 static int sa1100_rtc_suspend(struct platform_device *pdev, pm_message_t state)
 397 {
 398         if (device_may_wakeup(&pdev->dev))
 399                 enable_irq_wake(IRQ_RTCAlrm);
 400         return 0;
 401 }
 402
 403 static int sa1100_rtc_resume(struct platform_device *pdev)
 404 {
 405         if (device_may_wakeup(&pdev->dev))
 406                 disable_irq_wake(IRQ_RTCAlrm);
 407         return 0;
 408 }
 409 #else
 410 #define sa1100_rtc_suspend      NULL
 411 #define sa1100_rtc_resume       NULL
 412 #endif
 413
 414 static struct platform_driver sa1100_rtc_driver = {
 415         .probe          = sa1100_rtc_probe,
 416         .remove         = sa1100_rtc_remove,
 417         .suspend        = sa1100_rtc_suspend,
 418         .resume         = sa1100_rtc_resume,
 419         .driver         = {
 420                 .name           = "sa1100-rtc",
 421         },
 422 };
 423
 424 static int __init sa1100_rtc_init(void)
 425 {
 426         return platform_driver_register(&sa1100_rtc_driver);
 427 }
 428
 429 static void __exit sa1100_rtc_exit(void)
 430 {
 431         platform_driver_unregister(&sa1100_rtc_driver);
 432 }
 433
 434 module_init(sa1100_rtc_init);
 435 module_exit(sa1100_rtc_exit);
 436
 437 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
 438 MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)");
 439 MODULE_LICENSE("GPL");
 440 MODULE_ALIAS("platform:sa1100-rtc");