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
  33 #include <asm/bitops.h>
  34 #include <asm/hardware.h>
  35 #include <asm/irq.h>
  36 #include <asm/rtc.h>
  37
  38 #ifdef CONFIG_ARCH_PXA
  39 #include <asm/arch/pxa-regs.h>
  40 #endif
  41
  42 #define TIMER_FREQ              CLOCK_TICK_RATE
  43 #define RTC_DEF_DIVIDER         32768 - 1
  44 #define RTC_DEF_TRIM            0
  45
  46 static unsigned long rtc_freq = 1024;
  47 static struct rtc_time rtc_alarm;
  48 static DEFINE_SPINLOCK(sa1100_rtc_lock);
  49
  50 static int rtc_update_alarm(struct rtc_time *alrm)
  51 {
  52         struct rtc_time alarm_tm, now_tm;
  53         unsigned long now, time;
  54         int ret;
  55
  56         do {
  57                 now = RCNR;
  58                 rtc_time_to_tm(now, &now_tm);
  59                 rtc_next_alarm_time(&alarm_tm, &now_tm, alrm);
  60                 ret = rtc_tm_to_time(&alarm_tm, &time);
  61                 if (ret != 0)
  62                         break;
  63
  64                 RTSR = RTSR & (RTSR_HZE|RTSR_ALE|RTSR_AL);
  65                 RTAR = time;
  66         } while (now != RCNR);
  67
  68         return ret;
  69 }
  70
  71 static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id,
  72                 struct pt_regs *regs)
  73 {
  74         struct platform_device *pdev = to_platform_device(dev_id);
  75         struct rtc_device *rtc = platform_get_drvdata(pdev);
  76         unsigned int rtsr;
  77         unsigned long events = 0;
  78
  79         spin_lock(&sa1100_rtc_lock);
  80
  81         rtsr = RTSR;
  82         /* clear interrupt sources */
  83         RTSR = 0;
  84         RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2);
  85
  86         /* clear alarm interrupt if it has occurred */
  87         if (rtsr & RTSR_AL)
  88                 rtsr &= ~RTSR_ALE;
  89         RTSR = rtsr & (RTSR_ALE | RTSR_HZE);
  90
  91         /* update irq data & counter */
  92         if (rtsr & RTSR_AL)
  93                 events |= RTC_AF | RTC_IRQF;
  94         if (rtsr & RTSR_HZ)
  95                 events |= RTC_UF | RTC_IRQF;
  96
  97         rtc_update_irq(&rtc->class_dev, 1, events);
  98
  99         if (rtsr & RTSR_AL && rtc_periodic_alarm(&rtc_alarm))
 100                 rtc_update_alarm(&rtc_alarm);
 101
 102         spin_unlock(&sa1100_rtc_lock);
 103
 104         return IRQ_HANDLED;
 105 }
 106
 107 static int rtc_timer1_count;
 108
 109 static irqreturn_t timer1_interrupt(int irq, void *dev_id,
 110                 struct pt_regs *regs)
 111 {
 112         struct platform_device *pdev = to_platform_device(dev_id);
 113         struct rtc_device *rtc = platform_get_drvdata(pdev);
 114
 115         /*
 116          * If we match for the first time, rtc_timer1_count will be 1.
 117          * Otherwise, we wrapped around (very unlikely but
 118          * still possible) so compute the amount of missed periods.
 119          * The match reg is updated only when the data is actually retrieved
 120          * to avoid unnecessary interrupts.
 121          */
 122         OSSR = OSSR_M1; /* clear match on timer1 */
 123
 124         rtc_update_irq(&rtc->class_dev, rtc_timer1_count, RTC_PF | RTC_IRQF);
 125
 126         if (rtc_timer1_count == 1)
 127                 rtc_timer1_count = (rtc_freq * ((1<<30)/(TIMER_FREQ>>2)));
 128
 129         return IRQ_HANDLED;
 130 }
 131
 132 static int sa1100_rtc_read_callback(struct device *dev, int data)
 133 {
 134         if (data & RTC_PF) {
 135                 /* interpolate missed periods and set match for the next */
 136                 unsigned long period = TIMER_FREQ/rtc_freq;
 137                 unsigned long oscr = OSCR;
 138                 unsigned long osmr1 = OSMR1;
 139                 unsigned long missed = (oscr - osmr1)/period;
 140                 data += missed << 8;
 141                 OSSR = OSSR_M1; /* clear match on timer 1 */
 142                 OSMR1 = osmr1 + (missed + 1)*period;
 143                 /* Ensure we didn't miss another match in the mean time.
 144                  * Here we compare (match - OSCR) 8 instead of 0 --
 145                  * see comment in pxa_timer_interrupt() for explanation.
 146                  */
 147                 while( (signed long)((osmr1 = OSMR1) - OSCR) <= 8 ) {
 148                         data += 0x100;
 149                         OSSR = OSSR_M1; /* clear match on timer 1 */
 150                         OSMR1 = osmr1 + period;
 151                 }
 152         }
 153         return data;
 154 }
 155
 156 static int sa1100_rtc_open(struct device *dev)
 157 {
 158         int ret;
 159
 160         ret = request_irq(IRQ_RTC1Hz, sa1100_rtc_interrupt, SA_INTERRUPT,
 161                                 "rtc 1Hz", dev);
 162         if (ret) {
 163                 dev_err(dev, "IRQ %d already in use.\n", IRQ_RTC1Hz);
 164                 goto fail_ui;
 165         }
 166         ret = request_irq(IRQ_RTCAlrm, sa1100_rtc_interrupt, SA_INTERRUPT,
 167                                 "rtc Alrm", dev);
 168         if (ret) {
 169                 dev_err(dev, "IRQ %d already in use.\n", IRQ_RTCAlrm);
 170                 goto fail_ai;
 171         }
 172         ret = request_irq(IRQ_OST1, timer1_interrupt, SA_INTERRUPT,
 173                                 "rtc timer", dev);
 174         if (ret) {
 175                 dev_err(dev, "IRQ %d already in use.\n", IRQ_OST1);
 176                 goto fail_pi;
 177         }
 178         return 0;
 179
 180  fail_pi:
 181         free_irq(IRQ_RTCAlrm, dev);
 182  fail_ai:
 183         free_irq(IRQ_RTC1Hz, dev);
 184  fail_ui:
 185         return ret;
 186 }
 187
 188 static void sa1100_rtc_release(struct device *dev)
 189 {
 190         spin_lock_irq(&sa1100_rtc_lock);
 191         RTSR = 0;
 192         OIER &= ~OIER_E1;
 193         OSSR = OSSR_M1;
 194         spin_unlock_irq(&sa1100_rtc_lock);
 195
 196         free_irq(IRQ_OST1, dev);
 197         free_irq(IRQ_RTCAlrm, dev);
 198         free_irq(IRQ_RTC1Hz, dev);
 199 }
 200
 201
 202 static int sa1100_rtc_ioctl(struct device *dev, unsigned int cmd,
 203                 unsigned long arg)
 204 {
 205         switch(cmd) {
 206         case RTC_AIE_OFF:
 207                 spin_lock_irq(&sa1100_rtc_lock);
 208                 RTSR &= ~RTSR_ALE;
 209                 spin_unlock_irq(&sa1100_rtc_lock);
 210                 return 0;
 211         case RTC_AIE_ON:
 212                 spin_lock_irq(&sa1100_rtc_lock);
 213                 RTSR |= RTSR_ALE;
 214                 spin_unlock_irq(&sa1100_rtc_lock);
 215                 return 0;
 216         case RTC_UIE_OFF:
 217                 spin_lock_irq(&sa1100_rtc_lock);
 218                 RTSR &= ~RTSR_HZE;
 219                 spin_unlock_irq(&sa1100_rtc_lock);
 220                 return 0;
 221         case RTC_UIE_ON:
 222                 spin_lock_irq(&sa1100_rtc_lock);
 223                 RTSR |= RTSR_HZE;
 224                 spin_unlock_irq(&sa1100_rtc_lock);
 225                 return 0;
 226         case RTC_PIE_OFF:
 227                 spin_lock_irq(&sa1100_rtc_lock);
 228                 OIER &= ~OIER_E1;
 229                 spin_unlock_irq(&sa1100_rtc_lock);
 230                 return 0;
 231         case RTC_PIE_ON:
 232                 spin_lock_irq(&sa1100_rtc_lock);
 233                 OSMR1 = TIMER_FREQ/rtc_freq + OSCR;
 234                 OIER |= OIER_E1;
 235                 rtc_timer1_count = 1;
 236                 spin_unlock_irq(&sa1100_rtc_lock);
 237                 return 0;
 238         case RTC_IRQP_READ:
 239                 return put_user(rtc_freq, (unsigned long *)arg);
 240         case RTC_IRQP_SET:
 241                 if (arg < 1 || arg > TIMER_FREQ)
 242                         return -EINVAL;
 243                 rtc_freq = arg;
 244                 return 0;
 245         }
 246         return -ENOIOCTLCMD;
 247 }
 248
 249 static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm)
 250 {
 251         rtc_time_to_tm(RCNR, tm);
 252         return 0;
 253 }
 254
 255 static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm)
 256 {
 257         unsigned long time;
 258         int ret;
 259
 260         ret = rtc_tm_to_time(tm, &time);
 261         if (ret == 0)
 262                 RCNR = time;
 263         return ret;
 264 }
 265
 266 static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 267 {
 268         memcpy(&alrm->time, &rtc_alarm, sizeof(struct rtc_time));
 269         alrm->pending = RTSR & RTSR_AL ? 1 : 0;
 270         return 0;
 271 }
 272
 273 static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 274 {
 275         int ret;
 276
 277         spin_lock_irq(&sa1100_rtc_lock);
 278         ret = rtc_update_alarm(&alrm->time);
 279         if (ret == 0) {
 280                 memcpy(&rtc_alarm, &alrm->time, sizeof(struct rtc_time));
 281
 282                 if (alrm->enabled)
 283                         enable_irq_wake(IRQ_RTCAlrm);
 284                 else
 285                         disable_irq_wake(IRQ_RTCAlrm);
 286         }
 287         spin_unlock_irq(&sa1100_rtc_lock);
 288
 289         return ret;
 290 }
 291
 292 static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq)
 293 {
 294         seq_printf(seq, "trim/divider\t: 0x%08lx\n", RTTR);
 295         seq_printf(seq, "alarm_IRQ\t: %s\n",
 296                         (RTSR & RTSR_ALE) ? "yes" : "no" );
 297         seq_printf(seq, "update_IRQ\t: %s\n",
 298                         (RTSR & RTSR_HZE) ? "yes" : "no");
 299         seq_printf(seq, "periodic_IRQ\t: %s\n",
 300                         (OIER & OIER_E1) ? "yes" : "no");
 301         seq_printf(seq, "periodic_freq\t: %ld\n", rtc_freq);
 302
 303         return 0;
 304 }
 305
 306 static struct rtc_class_ops sa1100_rtc_ops = {
 307         .open = sa1100_rtc_open,
 308         .read_callback = sa1100_rtc_read_callback,
 309         .release = sa1100_rtc_release,
 310         .ioctl = sa1100_rtc_ioctl,
 311         .read_time = sa1100_rtc_read_time,
 312         .set_time = sa1100_rtc_set_time,
 313         .read_alarm = sa1100_rtc_read_alarm,
 314         .set_alarm = sa1100_rtc_set_alarm,
 315         .proc = sa1100_rtc_proc,
 316 };
 317
 318 static int sa1100_rtc_probe(struct platform_device *pdev)
 319 {
 320         struct rtc_device *rtc;
 321
 322         /*
 323          * According to the manual we should be able to let RTTR be zero
 324          * and then a default diviser for a 32.768KHz clock is used.
 325          * Apparently this doesn't work, at least for my SA1110 rev 5.
 326          * If the clock divider is uninitialized then reset it to the
 327          * default value to get the 1Hz clock.
 328          */
 329         if (RTTR == 0) {
 330                 RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16);
 331                 dev_warn(&pdev->dev, "warning: initializing default clock divider/trim value\n");
 332                 /* The current RTC value probably doesn't make sense either */
 333                 RCNR = 0;
 334         }
 335
 336         rtc = rtc_device_register(pdev->name, &pdev->dev, &sa1100_rtc_ops,
 337                                 THIS_MODULE);
 338
 339         if (IS_ERR(rtc))
 340                 return PTR_ERR(rtc);
 341
 342         platform_set_drvdata(pdev, rtc);
 343
 344         return 0;
 345 }
 346
 347 static int sa1100_rtc_remove(struct platform_device *pdev)
 348 {
 349         struct rtc_device *rtc = platform_get_drvdata(pdev);
 350
 351         if (rtc)
 352                 rtc_device_unregister(rtc);
 353
 354         return 0;
 355 }
 356
 357 static struct platform_driver sa1100_rtc_driver = {
 358         .probe          = sa1100_rtc_probe,
 359         .remove         = sa1100_rtc_remove,
 360         .driver         = {
 361                 .name           = "sa1100-rtc",
 362         },
 363 };
 364
 365 static int __init sa1100_rtc_init(void)
 366 {
 367         return platform_driver_register(&sa1100_rtc_driver);
 368 }
 369
 370 static void __exit sa1100_rtc_exit(void)
 371 {
 372         platform_driver_unregister(&sa1100_rtc_driver);
 373 }
 374
 375 module_init(sa1100_rtc_init);
 376 module_exit(sa1100_rtc_exit);
 377
 378 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
 379 MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)");
 380 MODULE_LICENSE("GPL");