LXR linux/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 <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
  46static unsigned long rtc_freq = 1024;
  47static struct rtc_time rtc_alarm;
  48static DEFINE_SPINLOCK(sa1100_rtc_lock);
  49
  50static 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
  71static 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, 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
 106static int rtc_timer1_count;
 107
 108static 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, 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
 130static 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
 154static 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
 186static 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
 200static 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
 247static 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
 253static 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
 264static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 265{
 266        u32     rtsr;
 267
 268        memcpy(&alrm->time, &rtc_alarm, sizeof(struct rtc_time));
 269        rtsr = RTSR;
 270        alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0;
 271        alrm->pending = (rtsr & RTSR_AL) ? 1 : 0;
 272        return 0;
 273}
 274
 275static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 276{
 277        int ret;
 278
 279        spin_lock_irq(&sa1100_rtc_lock);
 280        ret = rtc_update_alarm(&alrm->time);
 281        if (ret == 0) {
 282                if (alrm->enabled)
 283                        RTSR |= RTSR_ALE;
 284                else
 285                        RTSR &= ~RTSR_ALE;
 286        }
 287        spin_unlock_irq(&sa1100_rtc_lock);
 288
 289        return ret;
 290}
 291
 292static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq)
 293{
 294        seq_printf(seq, "trim/divider\t: 0x%08x\n", (u32) RTTR);
 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
 304static 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
 316static 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
 345static 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
 355static 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
 363static int __init sa1100_rtc_init(void)
 364{
 365        return platform_driver_register(&sa1100_rtc_driver);
 366}
 367
 368static void __exit sa1100_rtc_exit(void)
 369{
 370        platform_driver_unregister(&sa1100_rtc_driver);
 371}
 372
 373module_init(sa1100_rtc_init);
 374module_exit(sa1100_rtc_exit);
 375
 376MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
 377MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)");
 378MODULE_LICENSE("GPL");
 379