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@fluxnic.net>
  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/pm.h>
  31 #include <linux/slab.h>
  32 #include <linux/clk.h>
  33 #include <linux/io.h>
  34
  35 #include <mach/hardware.h>
  36 #include <asm/irq.h>
  37
  38 #define RTC_DEF_DIVIDER         (32768 - 1)
  39 #define RTC_DEF_TRIM            0
  40 #define RTC_FREQ                1024
  41
  42 #define RCNR            0x00    /* RTC Count Register */
  43 #define RTAR            0x04    /* RTC Alarm Register */
  44 #define RTSR            0x08    /* RTC Status Register */
  45 #define RTTR            0x0c    /* RTC Timer Trim Register */
  46
  47 #define RTSR_HZE        (1 << 3)        /* HZ interrupt enable */
  48 #define RTSR_ALE        (1 << 2)        /* RTC alarm interrupt enable */
  49 #define RTSR_HZ         (1 << 1)        /* HZ rising-edge detected */
  50 #define RTSR_AL         (1 << 0)        /* RTC alarm detected */
  51
  52 #define rtc_readl(sa1100_rtc, reg)      \
  53         readl_relaxed((sa1100_rtc)->base + (reg))
  54 #define rtc_writel(sa1100_rtc, reg, value)      \
  55         writel_relaxed((value), (sa1100_rtc)->base + (reg))
  56
  57 struct sa1100_rtc {
  58         struct resource         *ress;
  59         void __iomem            *base;
  60         struct clk              *clk;
  61         int                     irq_1Hz;
  62         int                     irq_Alrm;
  63         struct rtc_device       *rtc;
  64         spinlock_t              lock;           /* Protects this structure */
  65 };
  66 /*
  67  * Calculate the next alarm time given the requested alarm time mask
  68  * and the current time.
  69  */
  70 static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now,
  71         struct rtc_time *alrm)
  72 {
  73         unsigned long next_time;
  74         unsigned long now_time;
  75
  76         next->tm_year = now->tm_year;
  77         next->tm_mon = now->tm_mon;
  78         next->tm_mday = now->tm_mday;
  79         next->tm_hour = alrm->tm_hour;
  80         next->tm_min = alrm->tm_min;
  81         next->tm_sec = alrm->tm_sec;
  82
  83         rtc_tm_to_time(now, &now_time);
  84         rtc_tm_to_time(next, &next_time);
  85
  86         if (next_time < now_time) {
  87                 /* Advance one day */
  88                 next_time += 60 * 60 * 24;
  89                 rtc_time_to_tm(next_time, next);
  90         }
  91 }
  92
  93 static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id)
  94 {
  95         struct platform_device *pdev = to_platform_device(dev_id);
  96         struct sa1100_rtc *sa1100_rtc = platform_get_drvdata(pdev);
  97         unsigned int rtsr;
  98         unsigned long events = 0;
  99
 100         spin_lock(&sa1100_rtc->lock);
 101
 102         /* clear interrupt sources */
 103         rtsr = rtc_readl(sa1100_rtc, RTSR);
 104         rtc_writel(sa1100_rtc, RTSR, 0);
 105
 106         /* Fix for a nasty initialization problem the in SA11xx RTSR register.
 107          * See also the comments in sa1100_rtc_probe(). */
 108         if (rtsr & (RTSR_ALE | RTSR_HZE)) {
 109                 /* This is the original code, before there was the if test
 110                  * above. This code does not clear interrupts that were not
 111                  * enabled. */
 112                 rtc_writel(sa1100_rtc, RTSR, (RTSR_AL | RTSR_HZ) & (rtsr >> 2));
 113         } else {
 114                 /* For some reason, it is possible to enter this routine
 115                  * without interruptions enabled, it has been tested with
 116                  * several units (Bug in SA11xx chip?).
 117                  *
 118                  * This situation leads to an infinite "loop" of interrupt
 119                  * routine calling and as a result the processor seems to
 120                  * lock on its first call to open(). */
 121                 rtc_writel(sa1100_rtc, RTSR, (RTSR_AL | RTSR_HZ));
 122         }
 123
 124         /* clear alarm interrupt if it has occurred */
 125         if (rtsr & RTSR_AL)
 126                 rtsr &= ~RTSR_ALE;
 127         rtc_writel(sa1100_rtc, RTSR, rtsr & (RTSR_ALE | RTSR_HZE));
 128
 129         /* update irq data & counter */
 130         if (rtsr & RTSR_AL)
 131                 events |= RTC_AF | RTC_IRQF;
 132         if (rtsr & RTSR_HZ)
 133                 events |= RTC_UF | RTC_IRQF;
 134
 135         rtc_update_irq(sa1100_rtc->rtc, 1, events);
 136
 137         spin_unlock(&sa1100_rtc->lock);
 138
 139         return IRQ_HANDLED;
 140 }
 141
 142 static int sa1100_rtc_open(struct device *dev)
 143 {
 144         struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);
 145         int ret;
 146
 147         ret = request_irq(sa1100_rtc->irq_1Hz, sa1100_rtc_interrupt,
 148                                 IRQF_DISABLED, "rtc 1Hz", dev);
 149         if (ret) {
 150                 dev_err(dev, "IRQ %d already in use.\n", sa1100_rtc->irq_1Hz);
 151                 goto fail_ui;
 152         }
 153         ret = request_irq(sa1100_rtc->irq_Alrm, sa1100_rtc_interrupt,
 154                                 IRQF_DISABLED, "rtc Alrm", dev);
 155         if (ret) {
 156                 dev_err(dev, "IRQ %d already in use.\n", sa1100_rtc->irq_Alrm);
 157                 goto fail_ai;
 158         }
 159         sa1100_rtc->rtc->max_user_freq = RTC_FREQ;
 160         rtc_irq_set_freq(sa1100_rtc->rtc, NULL, RTC_FREQ);
 161
 162         return 0;
 163
 164  fail_ai:
 165         free_irq(sa1100_rtc->irq_1Hz, dev);
 166  fail_ui:
 167         return ret;
 168 }
 169
 170 static void sa1100_rtc_release(struct device *dev)
 171 {
 172         struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);
 173
 174         spin_lock_irq(&sa1100_rtc->lock);
 175         rtc_writel(sa1100_rtc, RTSR, 0);
 176         spin_unlock_irq(&sa1100_rtc->lock);
 177
 178         free_irq(sa1100_rtc->irq_Alrm, dev);
 179         free_irq(sa1100_rtc->irq_1Hz, dev);
 180 }
 181
 182 static int sa1100_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 183 {
 184         struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);
 185         unsigned int rtsr;
 186
 187         spin_lock_irq(&sa1100_rtc->lock);
 188
 189         rtsr = rtc_readl(sa1100_rtc, RTSR);
 190         if (enabled)
 191                 rtsr |= RTSR_ALE;
 192         else
 193                 rtsr &= ~RTSR_ALE;
 194         rtc_writel(sa1100_rtc, RTSR, rtsr);
 195
 196         spin_unlock_irq(&sa1100_rtc->lock);
 197         return 0;
 198 }
 199
 200 static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm)
 201 {
 202         struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);
 203
 204         rtc_time_to_tm(rtc_readl(sa1100_rtc, RCNR), tm);
 205         return 0;
 206 }
 207
 208 static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm)
 209 {
 210         struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);
 211         unsigned long time;
 212         int ret;
 213
 214         ret = rtc_tm_to_time(tm, &time);
 215         if (ret == 0)
 216                 rtc_writel(sa1100_rtc, RCNR, time);
 217         return ret;
 218 }
 219
 220 static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 221 {
 222         struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);
 223         unsigned long time;
 224         unsigned int rtsr;
 225
 226         time = rtc_readl(sa1100_rtc, RCNR);
 227         rtc_time_to_tm(time, &alrm->time);
 228         rtsr = rtc_readl(sa1100_rtc, RTSR);
 229         alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0;
 230         alrm->pending = (rtsr & RTSR_AL) ? 1 : 0;
 231         return 0;
 232 }
 233
 234 static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 235 {
 236         struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);
 237         struct rtc_time now_tm, alarm_tm;
 238         unsigned long time, alarm;
 239         unsigned int rtsr;
 240
 241         spin_lock_irq(&sa1100_rtc->lock);
 242
 243         time = rtc_readl(sa1100_rtc, RCNR);
 244         rtc_time_to_tm(time, &now_tm);
 245         rtc_next_alarm_time(&alarm_tm, &now_tm, &alrm->time);
 246         rtc_tm_to_time(&alarm_tm, &alarm);
 247         rtc_writel(sa1100_rtc, RTAR, alarm);
 248
 249         rtsr = rtc_readl(sa1100_rtc, RTSR);
 250         if (alrm->enabled)
 251                 rtsr |= RTSR_ALE;
 252         else
 253                 rtsr &= ~RTSR_ALE;
 254         rtc_writel(sa1100_rtc, RTSR, rtsr);
 255
 256         spin_unlock_irq(&sa1100_rtc->lock);
 257
 258         return 0;
 259 }
 260
 261 static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq)
 262 {
 263         struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);
 264
 265         seq_printf(seq, "trim/divider\t\t: 0x%08x\n",
 266                         rtc_readl(sa1100_rtc, RTTR));
 267         seq_printf(seq, "RTSR\t\t\t: 0x%08x\n",
 268                         rtc_readl(sa1100_rtc, RTSR));
 269         return 0;
 270 }
 271
 272 static const struct rtc_class_ops sa1100_rtc_ops = {
 273         .open = sa1100_rtc_open,
 274         .release = sa1100_rtc_release,
 275         .read_time = sa1100_rtc_read_time,
 276         .set_time = sa1100_rtc_set_time,
 277         .read_alarm = sa1100_rtc_read_alarm,
 278         .set_alarm = sa1100_rtc_set_alarm,
 279         .proc = sa1100_rtc_proc,
 280         .alarm_irq_enable = sa1100_rtc_alarm_irq_enable,
 281 };
 282
 283 static int sa1100_rtc_probe(struct platform_device *pdev)
 284 {
 285         struct sa1100_rtc *sa1100_rtc;
 286         unsigned int rttr;
 287         int ret;
 288
 289         sa1100_rtc = kzalloc(sizeof(struct sa1100_rtc), GFP_KERNEL);
 290         if (!sa1100_rtc)
 291                 return -ENOMEM;
 292
 293         spin_lock_init(&sa1100_rtc->lock);
 294         platform_set_drvdata(pdev, sa1100_rtc);
 295
 296         ret = -ENXIO;
 297         sa1100_rtc->ress = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 298         if (!sa1100_rtc->ress) {
 299                 dev_err(&pdev->dev, "No I/O memory resource defined\n");
 300                 goto err_ress;
 301         }
 302
 303         sa1100_rtc->irq_1Hz = platform_get_irq(pdev, 0);
 304         if (sa1100_rtc->irq_1Hz < 0) {
 305                 dev_err(&pdev->dev, "No 1Hz IRQ resource defined\n");
 306                 goto err_ress;
 307         }
 308         sa1100_rtc->irq_Alrm = platform_get_irq(pdev, 1);
 309         if (sa1100_rtc->irq_Alrm < 0) {
 310                 dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
 311                 goto err_ress;
 312         }
 313
 314         ret = -ENOMEM;
 315         sa1100_rtc->base = ioremap(sa1100_rtc->ress->start,
 316                                 resource_size(sa1100_rtc->ress));
 317         if (!sa1100_rtc->base) {
 318                 dev_err(&pdev->dev, "Unable to map pxa RTC I/O memory\n");
 319                 goto err_map;
 320         }
 321
 322         sa1100_rtc->clk = clk_get(&pdev->dev, NULL);
 323         if (IS_ERR(sa1100_rtc->clk)) {
 324                 dev_err(&pdev->dev, "failed to find rtc clock source\n");
 325                 ret = PTR_ERR(sa1100_rtc->clk);
 326                 goto err_clk;
 327         }
 328         clk_prepare(sa1100_rtc->clk);
 329         clk_enable(sa1100_rtc->clk);
 330
 331         /*
 332          * According to the manual we should be able to let RTTR be zero
 333          * and then a default diviser for a 32.768KHz clock is used.
 334          * Apparently this doesn't work, at least for my SA1110 rev 5.
 335          * If the clock divider is uninitialized then reset it to the
 336          * default value to get the 1Hz clock.
 337          */
 338         if (rtc_readl(sa1100_rtc, RTTR) == 0) {
 339                 rttr = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16);
 340                 rtc_writel(sa1100_rtc, RTTR, rttr);
 341                 dev_warn(&pdev->dev, "warning: initializing default clock"
 342                          " divider/trim value\n");
 343                 /* The current RTC value probably doesn't make sense either */
 344                 rtc_writel(sa1100_rtc, RCNR, 0);
 345         }
 346
 347         device_init_wakeup(&pdev->dev, 1);
 348
 349         sa1100_rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
 350                                                 &sa1100_rtc_ops, THIS_MODULE);
 351         if (IS_ERR(sa1100_rtc->rtc)) {
 352                 dev_err(&pdev->dev, "Failed to register RTC device -> %d\n",
 353                         ret);
 354                 goto err_rtc_reg;
 355         }
 356         /* Fix for a nasty initialization problem the in SA11xx RTSR register.
 357          * See also the comments in sa1100_rtc_interrupt().
 358          *
 359          * Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an
 360          * interrupt pending, even though interrupts were never enabled.
 361          * In this case, this bit it must be reset before enabling
 362          * interruptions to avoid a nonexistent interrupt to occur.
 363          *
 364          * In principle, the same problem would apply to bit 0, although it has
 365          * never been observed to happen.
 366          *
 367          * This issue is addressed both here and in sa1100_rtc_interrupt().
 368          * If the issue is not addressed here, in the times when the processor
 369          * wakes up with the bit set there will be one spurious interrupt.
 370          *
 371          * The issue is also dealt with in sa1100_rtc_interrupt() to be on the
 372          * safe side, once the condition that lead to this strange
 373          * initialization is unknown and could in principle happen during
 374          * normal processing.
 375          *
 376          * Notice that clearing bit 1 and 0 is accomplished by writting ONES to
 377          * the corresponding bits in RTSR. */
 378         rtc_writel(sa1100_rtc, RTSR, (RTSR_AL | RTSR_HZ));
 379
 380         return 0;
 381
 382 err_rtc_reg:
 383 err_clk:
 384         iounmap(sa1100_rtc->base);
 385 err_ress:
 386 err_map:
 387         kfree(sa1100_rtc);
 388         return ret;
 389 }
 390
 391 static int sa1100_rtc_remove(struct platform_device *pdev)
 392 {
 393         struct sa1100_rtc *sa1100_rtc = platform_get_drvdata(pdev);
 394
 395         rtc_device_unregister(sa1100_rtc->rtc);
 396         clk_disable(sa1100_rtc->clk);
 397         clk_unprepare(sa1100_rtc->clk);
 398         iounmap(sa1100_rtc->base);
 399         return 0;
 400 }
 401
 402 #ifdef CONFIG_PM
 403 static int sa1100_rtc_suspend(struct device *dev)
 404 {
 405         struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);
 406
 407         if (device_may_wakeup(dev))
 408                 enable_irq_wake(sa1100_rtc->irq_Alrm);
 409         return 0;
 410 }
 411
 412 static int sa1100_rtc_resume(struct device *dev)
 413 {
 414         struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);
 415
 416         if (device_may_wakeup(dev))
 417                 disable_irq_wake(sa1100_rtc->irq_Alrm);
 418         return 0;
 419 }
 420
 421 static const struct dev_pm_ops sa1100_rtc_pm_ops = {
 422         .suspend        = sa1100_rtc_suspend,
 423         .resume         = sa1100_rtc_resume,
 424 };
 425 #endif
 426
 427 static struct platform_driver sa1100_rtc_driver = {
 428         .probe          = sa1100_rtc_probe,
 429         .remove         = sa1100_rtc_remove,
 430         .driver         = {
 431                 .name   = "sa1100-rtc",
 432 #ifdef CONFIG_PM
 433                 .pm     = &sa1100_rtc_pm_ops,
 434 #endif
 435         },
 436 };
 437
 438 module_platform_driver(sa1100_rtc_driver);
 439
 440 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
 441 MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)");
 442 MODULE_LICENSE("GPL");
 443 MODULE_ALIAS("platform:sa1100-rtc");