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