LXR linux/drivers/rtc/rtc-at91rm9200.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *      Real Time Clock interface for Linux on Atmel AT91RM9200
   4 *
   5 *      Copyright (C) 2002 Rick Bronson
   6 *
   7 *      Converted to RTC class model by Andrew Victor
   8 *
   9 *      Ported to Linux 2.6 by Steven Scholz
  10 *      Based on s3c2410-rtc.c Simtec Electronics
  11 *
  12 *      Based on sa1100-rtc.c by Nils Faerber
  13 *      Based on rtc.c by Paul Gortmaker
  14 */
  15
  16#include <linux/bcd.h>
  17#include <linux/clk.h>
  18#include <linux/completion.h>
  19#include <linux/interrupt.h>
  20#include <linux/ioctl.h>
  21#include <linux/io.h>
  22#include <linux/kernel.h>
  23#include <linux/module.h>
  24#include <linux/of_device.h>
  25#include <linux/of.h>
  26#include <linux/platform_device.h>
  27#include <linux/rtc.h>
  28#include <linux/spinlock.h>
  29#include <linux/suspend.h>
  30#include <linux/time.h>
  31#include <linux/uaccess.h>
  32
  33#include "rtc-at91rm9200.h"
  34
  35#define at91_rtc_read(field) \
  36        readl_relaxed(at91_rtc_regs + field)
  37#define at91_rtc_write(field, val) \
  38        writel_relaxed((val), at91_rtc_regs + field)
  39
  40struct at91_rtc_config {
  41        bool use_shadow_imr;
  42};
  43
  44static const struct at91_rtc_config *at91_rtc_config;
  45static DECLARE_COMPLETION(at91_rtc_updated);
  46static DECLARE_COMPLETION(at91_rtc_upd_rdy);
  47static void __iomem *at91_rtc_regs;
  48static int irq;
  49static DEFINE_SPINLOCK(at91_rtc_lock);
  50static u32 at91_rtc_shadow_imr;
  51static bool suspended;
  52static DEFINE_SPINLOCK(suspended_lock);
  53static unsigned long cached_events;
  54static u32 at91_rtc_imr;
  55static struct clk *sclk;
  56
  57static void at91_rtc_write_ier(u32 mask)
  58{
  59        unsigned long flags;
  60
  61        spin_lock_irqsave(&at91_rtc_lock, flags);
  62        at91_rtc_shadow_imr |= mask;
  63        at91_rtc_write(AT91_RTC_IER, mask);
  64        spin_unlock_irqrestore(&at91_rtc_lock, flags);
  65}
  66
  67static void at91_rtc_write_idr(u32 mask)
  68{
  69        unsigned long flags;
  70
  71        spin_lock_irqsave(&at91_rtc_lock, flags);
  72        at91_rtc_write(AT91_RTC_IDR, mask);
  73        /*
  74         * Register read back (of any RTC-register) needed to make sure
  75         * IDR-register write has reached the peripheral before updating
  76         * shadow mask.
  77         *
  78         * Note that there is still a possibility that the mask is updated
  79         * before interrupts have actually been disabled in hardware. The only
  80         * way to be certain would be to poll the IMR-register, which is is
  81         * the very register we are trying to emulate. The register read back
  82         * is a reasonable heuristic.
  83         */
  84        at91_rtc_read(AT91_RTC_SR);
  85        at91_rtc_shadow_imr &= ~mask;
  86        spin_unlock_irqrestore(&at91_rtc_lock, flags);
  87}
  88
  89static u32 at91_rtc_read_imr(void)
  90{
  91        unsigned long flags;
  92        u32 mask;
  93
  94        if (at91_rtc_config->use_shadow_imr) {
  95                spin_lock_irqsave(&at91_rtc_lock, flags);
  96                mask = at91_rtc_shadow_imr;
  97                spin_unlock_irqrestore(&at91_rtc_lock, flags);
  98        } else {
  99                mask = at91_rtc_read(AT91_RTC_IMR);
 100        }
 101
 102        return mask;
 103}
 104
 105/*
 106 * Decode time/date into rtc_time structure
 107 */
 108static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
 109                                struct rtc_time *tm)
 110{
 111        unsigned int time, date;
 112
 113        /* must read twice in case it changes */
 114        do {
 115                time = at91_rtc_read(timereg);
 116                date = at91_rtc_read(calreg);
 117        } while ((time != at91_rtc_read(timereg)) ||
 118                        (date != at91_rtc_read(calreg)));
 119
 120        tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
 121        tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
 122        tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
 123
 124        /*
 125         * The Calendar Alarm register does not have a field for
 126         * the year - so these will return an invalid value.
 127         */
 128        tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;     /* century */
 129        tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);    /* year */
 130
 131        tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
 132        tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
 133        tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
 134}
 135
 136/*
 137 * Read current time and date in RTC
 138 */
 139static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
 140{
 141        at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
 142        tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 143        tm->tm_year = tm->tm_year - 1900;
 144
 145        dev_dbg(dev, "%s(): %ptR\n", __func__, tm);
 146
 147        return 0;
 148}
 149
 150/*
 151 * Set current time and date in RTC
 152 */
 153static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
 154{
 155        unsigned long cr;
 156
 157        dev_dbg(dev, "%s(): %ptR\n", __func__, tm);
 158
 159        wait_for_completion(&at91_rtc_upd_rdy);
 160
 161        /* Stop Time/Calendar from counting */
 162        cr = at91_rtc_read(AT91_RTC_CR);
 163        at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
 164
 165        at91_rtc_write_ier(AT91_RTC_ACKUPD);
 166        wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
 167        at91_rtc_write_idr(AT91_RTC_ACKUPD);
 168
 169        at91_rtc_write(AT91_RTC_TIMR,
 170                          bin2bcd(tm->tm_sec) << 0
 171                        | bin2bcd(tm->tm_min) << 8
 172                        | bin2bcd(tm->tm_hour) << 16);
 173
 174        at91_rtc_write(AT91_RTC_CALR,
 175                          bin2bcd((tm->tm_year + 1900) / 100)   /* century */
 176                        | bin2bcd(tm->tm_year % 100) << 8       /* year */
 177                        | bin2bcd(tm->tm_mon + 1) << 16         /* tm_mon starts at zero */
 178                        | bin2bcd(tm->tm_wday + 1) << 21        /* day of the week [0-6], Sunday=0 */
 179                        | bin2bcd(tm->tm_mday) << 24);
 180
 181        /* Restart Time/Calendar */
 182        cr = at91_rtc_read(AT91_RTC_CR);
 183        at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
 184        at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
 185        at91_rtc_write_ier(AT91_RTC_SECEV);
 186
 187        return 0;
 188}
 189
 190/*
 191 * Read alarm time and date in RTC
 192 */
 193static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 194{
 195        struct rtc_time *tm = &alrm->time;
 196
 197        at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
 198        tm->tm_year = -1;
 199
 200        alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
 201                        ? 1 : 0;
 202
 203        dev_dbg(dev, "%s(): %ptR %sabled\n", __func__, tm,
 204                alrm->enabled ? "en" : "dis");
 205
 206        return 0;
 207}
 208
 209/*
 210 * Set alarm time and date in RTC
 211 */
 212static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 213{
 214        struct rtc_time tm;
 215
 216        at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
 217
 218        tm.tm_mon = alrm->time.tm_mon;
 219        tm.tm_mday = alrm->time.tm_mday;
 220        tm.tm_hour = alrm->time.tm_hour;
 221        tm.tm_min = alrm->time.tm_min;
 222        tm.tm_sec = alrm->time.tm_sec;
 223
 224        at91_rtc_write_idr(AT91_RTC_ALARM);
 225        at91_rtc_write(AT91_RTC_TIMALR,
 226                  bin2bcd(tm.tm_sec) << 0
 227                | bin2bcd(tm.tm_min) << 8
 228                | bin2bcd(tm.tm_hour) << 16
 229                | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
 230        at91_rtc_write(AT91_RTC_CALALR,
 231                  bin2bcd(tm.tm_mon + 1) << 16          /* tm_mon starts at zero */
 232                | bin2bcd(tm.tm_mday) << 24
 233                | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
 234
 235        if (alrm->enabled) {
 236                at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 237                at91_rtc_write_ier(AT91_RTC_ALARM);
 238        }
 239
 240        dev_dbg(dev, "%s(): %ptR\n", __func__, &tm);
 241
 242        return 0;
 243}
 244
 245static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 246{
 247        dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
 248
 249        if (enabled) {
 250                at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 251                at91_rtc_write_ier(AT91_RTC_ALARM);
 252        } else
 253                at91_rtc_write_idr(AT91_RTC_ALARM);
 254
 255        return 0;
 256}
 257/*
 258 * Provide additional RTC information in /proc/driver/rtc
 259 */
 260static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
 261{
 262        unsigned long imr = at91_rtc_read_imr();
 263
 264        seq_printf(seq, "update_IRQ\t: %s\n",
 265                        (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
 266        seq_printf(seq, "periodic_IRQ\t: %s\n",
 267                        (imr & AT91_RTC_SECEV) ? "yes" : "no");
 268
 269        return 0;
 270}
 271
 272/*
 273 * IRQ handler for the RTC
 274 */
 275static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
 276{
 277        struct platform_device *pdev = dev_id;
 278        struct rtc_device *rtc = platform_get_drvdata(pdev);
 279        unsigned int rtsr;
 280        unsigned long events = 0;
 281        int ret = IRQ_NONE;
 282
 283        spin_lock(&suspended_lock);
 284        rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
 285        if (rtsr) {             /* this interrupt is shared!  Is it ours? */
 286                if (rtsr & AT91_RTC_ALARM)
 287                        events |= (RTC_AF | RTC_IRQF);
 288                if (rtsr & AT91_RTC_SECEV) {
 289                        complete(&at91_rtc_upd_rdy);
 290                        at91_rtc_write_idr(AT91_RTC_SECEV);
 291                }
 292                if (rtsr & AT91_RTC_ACKUPD)
 293                        complete(&at91_rtc_updated);
 294
 295                at91_rtc_write(AT91_RTC_SCCR, rtsr);    /* clear status reg */
 296
 297                if (!suspended) {
 298                        rtc_update_irq(rtc, 1, events);
 299
 300                        dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n",
 301                                __func__, events >> 8, events & 0x000000FF);
 302                } else {
 303                        cached_events |= events;
 304                        at91_rtc_write_idr(at91_rtc_imr);
 305                        pm_system_wakeup();
 306                }
 307
 308                ret = IRQ_HANDLED;
 309        }
 310        spin_unlock(&suspended_lock);
 311
 312        return ret;
 313}
 314
 315static const struct at91_rtc_config at91rm9200_config = {
 316};
 317
 318static const struct at91_rtc_config at91sam9x5_config = {
 319        .use_shadow_imr = true,
 320};
 321
 322#ifdef CONFIG_OF
 323static const struct of_device_id at91_rtc_dt_ids[] = {
 324        {
 325                .compatible = "atmel,at91rm9200-rtc",
 326                .data = &at91rm9200_config,
 327        }, {
 328                .compatible = "atmel,at91sam9x5-rtc",
 329                .data = &at91sam9x5_config,
 330        }, {
 331                /* sentinel */
 332        }
 333};
 334MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
 335#endif
 336
 337static const struct at91_rtc_config *
 338at91_rtc_get_config(struct platform_device *pdev)
 339{
 340        const struct of_device_id *match;
 341
 342        if (pdev->dev.of_node) {
 343                match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
 344                if (!match)
 345                        return NULL;
 346                return (const struct at91_rtc_config *)match->data;
 347        }
 348
 349        return &at91rm9200_config;
 350}
 351
 352static const struct rtc_class_ops at91_rtc_ops = {
 353        .read_time      = at91_rtc_readtime,
 354        .set_time       = at91_rtc_settime,
 355        .read_alarm     = at91_rtc_readalarm,
 356        .set_alarm      = at91_rtc_setalarm,
 357        .proc           = at91_rtc_proc,
 358        .alarm_irq_enable = at91_rtc_alarm_irq_enable,
 359};
 360
 361/*
 362 * Initialize and install RTC driver
 363 */
 364static int __init at91_rtc_probe(struct platform_device *pdev)
 365{
 366        struct rtc_device *rtc;
 367        struct resource *regs;
 368        int ret = 0;
 369
 370        at91_rtc_config = at91_rtc_get_config(pdev);
 371        if (!at91_rtc_config)
 372                return -ENODEV;
 373
 374        regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 375        if (!regs) {
 376                dev_err(&pdev->dev, "no mmio resource defined\n");
 377                return -ENXIO;
 378        }
 379
 380        irq = platform_get_irq(pdev, 0);
 381        if (irq < 0) {
 382                dev_err(&pdev->dev, "no irq resource defined\n");
 383                return -ENXIO;
 384        }
 385
 386        at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start,
 387                                     resource_size(regs));
 388        if (!at91_rtc_regs) {
 389                dev_err(&pdev->dev, "failed to map registers, aborting.\n");
 390                return -ENOMEM;
 391        }
 392
 393        rtc = devm_rtc_allocate_device(&pdev->dev);
 394        if (IS_ERR(rtc))
 395                return PTR_ERR(rtc);
 396        platform_set_drvdata(pdev, rtc);
 397
 398        sclk = devm_clk_get(&pdev->dev, NULL);
 399        if (IS_ERR(sclk))
 400                return PTR_ERR(sclk);
 401
 402        ret = clk_prepare_enable(sclk);
 403        if (ret) {
 404                dev_err(&pdev->dev, "Could not enable slow clock\n");
 405                return ret;
 406        }
 407
 408        at91_rtc_write(AT91_RTC_CR, 0);
 409        at91_rtc_write(AT91_RTC_MR, 0);         /* 24 hour mode */
 410
 411        /* Disable all interrupts */
 412        at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 413                                        AT91_RTC_SECEV | AT91_RTC_TIMEV |
 414                                        AT91_RTC_CALEV);
 415
 416        ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt,
 417                               IRQF_SHARED | IRQF_COND_SUSPEND,
 418                               "at91_rtc", pdev);
 419        if (ret) {
 420                dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
 421                goto err_clk;
 422        }
 423
 424        /* cpu init code should really have flagged this device as
 425         * being wake-capable; if it didn't, do that here.
 426         */
 427        if (!device_can_wakeup(&pdev->dev))
 428                device_init_wakeup(&pdev->dev, 1);
 429
 430        rtc->ops = &at91_rtc_ops;
 431        rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
 432        rtc->range_max = RTC_TIMESTAMP_END_2099;
 433        ret = rtc_register_device(rtc);
 434        if (ret)
 435                goto err_clk;
 436
 437        /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
 438         * completion.
 439         */
 440        at91_rtc_write_ier(AT91_RTC_SECEV);
 441
 442        dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
 443        return 0;
 444
 445err_clk:
 446        clk_disable_unprepare(sclk);
 447
 448        return ret;
 449}
 450
 451/*
 452 * Disable and remove the RTC driver
 453 */
 454static int __exit at91_rtc_remove(struct platform_device *pdev)
 455{
 456        /* Disable all interrupts */
 457        at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 458                                        AT91_RTC_SECEV | AT91_RTC_TIMEV |
 459                                        AT91_RTC_CALEV);
 460
 461        clk_disable_unprepare(sclk);
 462
 463        return 0;
 464}
 465
 466static void at91_rtc_shutdown(struct platform_device *pdev)
 467{
 468        /* Disable all interrupts */
 469        at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 470                                        AT91_RTC_SECEV | AT91_RTC_TIMEV |
 471                                        AT91_RTC_CALEV);
 472}
 473
 474#ifdef CONFIG_PM_SLEEP
 475
 476/* AT91RM9200 RTC Power management control */
 477
 478static int at91_rtc_suspend(struct device *dev)
 479{
 480        /* this IRQ is shared with DBGU and other hardware which isn't
 481         * necessarily doing PM like we are...
 482         */
 483        at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 484
 485        at91_rtc_imr = at91_rtc_read_imr()
 486                        & (AT91_RTC_ALARM|AT91_RTC_SECEV);
 487        if (at91_rtc_imr) {
 488                if (device_may_wakeup(dev)) {
 489                        unsigned long flags;
 490
 491                        enable_irq_wake(irq);
 492
 493                        spin_lock_irqsave(&suspended_lock, flags);
 494                        suspended = true;
 495                        spin_unlock_irqrestore(&suspended_lock, flags);
 496                } else {
 497                        at91_rtc_write_idr(at91_rtc_imr);
 498                }
 499        }
 500        return 0;
 501}
 502
 503static int at91_rtc_resume(struct device *dev)
 504{
 505        struct rtc_device *rtc = dev_get_drvdata(dev);
 506
 507        if (at91_rtc_imr) {
 508                if (device_may_wakeup(dev)) {
 509                        unsigned long flags;
 510
 511                        spin_lock_irqsave(&suspended_lock, flags);
 512
 513                        if (cached_events) {
 514                                rtc_update_irq(rtc, 1, cached_events);
 515                                cached_events = 0;
 516                        }
 517
 518                        suspended = false;
 519                        spin_unlock_irqrestore(&suspended_lock, flags);
 520
 521                        disable_irq_wake(irq);
 522                }
 523                at91_rtc_write_ier(at91_rtc_imr);
 524        }
 525        return 0;
 526}
 527#endif
 528
 529static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
 530
 531static struct platform_driver at91_rtc_driver = {
 532        .remove         = __exit_p(at91_rtc_remove),
 533        .shutdown       = at91_rtc_shutdown,
 534        .driver         = {
 535                .name   = "at91_rtc",
 536                .pm     = &at91_rtc_pm_ops,
 537                .of_match_table = of_match_ptr(at91_rtc_dt_ids),
 538        },
 539};
 540
 541module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
 542
 543MODULE_AUTHOR("Rick Bronson");
 544MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
 545MODULE_LICENSE("GPL");
 546MODULE_ALIAS("platform:at91_rtc");
 547