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