drivers/rtc/rtc-s3c.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* drivers/rtc/rtc-s3c.c
   3  *
   4  * Copyright (c) 2010 Samsung Electronics Co., Ltd.
   5  *              http://www.samsung.com/
   6  *
   7  * Copyright (c) 2004,2006 Simtec Electronics
   8  *      Ben Dooks, <ben@simtec.co.uk>
   9  *      http://armlinux.simtec.co.uk/
  10  *
  11  * S3C2410/S3C2440/S3C24XX Internal RTC Driver
  12 */
  13
  14 #include <linux/module.h>
  15 #include <linux/fs.h>
  16 #include <linux/string.h>
  17 #include <linux/init.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/rtc.h>
  21 #include <linux/bcd.h>
  22 #include <linux/clk.h>
  23 #include <linux/log2.h>
  24 #include <linux/slab.h>
  25 #include <linux/of.h>
  26 #include <linux/of_device.h>
  27 #include <linux/uaccess.h>
  28 #include <linux/io.h>
  29
  30 #include <asm/irq.h>
  31 #include "rtc-s3c.h"
  32
  33 struct s3c_rtc {
  34         struct device *dev;
  35         struct rtc_device *rtc;
  36
  37         void __iomem *base;
  38         struct clk *rtc_clk;
  39         struct clk *rtc_src_clk;
  40         bool alarm_enabled;
  41
  42         const struct s3c_rtc_data *data;
  43
  44         int irq_alarm;
  45         spinlock_t alarm_lock;
  46
  47         bool wake_en;
  48 };
  49
  50 struct s3c_rtc_data {
  51         bool needs_src_clk;
  52
  53         void (*irq_handler) (struct s3c_rtc *info, int mask);
  54         void (*enable) (struct s3c_rtc *info);
  55         void (*disable) (struct s3c_rtc *info);
  56 };
  57
  58 static int s3c_rtc_enable_clk(struct s3c_rtc *info)
  59 {
  60         int ret;
  61
  62         ret = clk_enable(info->rtc_clk);
  63         if (ret)
  64                 return ret;
  65
  66         if (info->data->needs_src_clk) {
  67                 ret = clk_enable(info->rtc_src_clk);
  68                 if (ret) {
  69                         clk_disable(info->rtc_clk);
  70                         return ret;
  71                 }
  72         }
  73         return 0;
  74 }
  75
  76 static void s3c_rtc_disable_clk(struct s3c_rtc *info)
  77 {
  78         if (info->data->needs_src_clk)
  79                 clk_disable(info->rtc_src_clk);
  80         clk_disable(info->rtc_clk);
  81 }
  82
  83 /* IRQ Handler */
  84 static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)
  85 {
  86         struct s3c_rtc *info = (struct s3c_rtc *)id;
  87
  88         if (info->data->irq_handler)
  89                 info->data->irq_handler(info, S3C2410_INTP_ALM);
  90
  91         return IRQ_HANDLED;
  92 }
  93
  94 /* Update control registers */
  95 static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)
  96 {
  97         struct s3c_rtc *info = dev_get_drvdata(dev);
  98         unsigned long flags;
  99         unsigned int tmp;
 100         int ret;
 101
 102         dev_dbg(info->dev, "%s: aie=%d\n", __func__, enabled);
 103
 104         ret = s3c_rtc_enable_clk(info);
 105         if (ret)
 106                 return ret;
 107
 108         tmp = readb(info->base + S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;
 109
 110         if (enabled)
 111                 tmp |= S3C2410_RTCALM_ALMEN;
 112
 113         writeb(tmp, info->base + S3C2410_RTCALM);
 114
 115         spin_lock_irqsave(&info->alarm_lock, flags);
 116
 117         if (info->alarm_enabled && !enabled)
 118                 s3c_rtc_disable_clk(info);
 119         else if (!info->alarm_enabled && enabled)
 120                 ret = s3c_rtc_enable_clk(info);
 121
 122         info->alarm_enabled = enabled;
 123         spin_unlock_irqrestore(&info->alarm_lock, flags);
 124
 125         s3c_rtc_disable_clk(info);
 126
 127         return ret;
 128 }
 129
 130 /* Time read/write */
 131 static int s3c_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
 132 {
 133         struct s3c_rtc *info = dev_get_drvdata(dev);
 134         unsigned int have_retried = 0;
 135         int ret;
 136
 137         ret = s3c_rtc_enable_clk(info);
 138         if (ret)
 139                 return ret;
 140
 141 retry_get_time:
 142         rtc_tm->tm_min  = readb(info->base + S3C2410_RTCMIN);
 143         rtc_tm->tm_hour = readb(info->base + S3C2410_RTCHOUR);
 144         rtc_tm->tm_mday = readb(info->base + S3C2410_RTCDATE);
 145         rtc_tm->tm_mon  = readb(info->base + S3C2410_RTCMON);
 146         rtc_tm->tm_year = readb(info->base + S3C2410_RTCYEAR);
 147         rtc_tm->tm_sec  = readb(info->base + S3C2410_RTCSEC);
 148
 149         /* the only way to work out whether the system was mid-update
 150          * when we read it is to check the second counter, and if it
 151          * is zero, then we re-try the entire read
 152          */
 153
 154         if (rtc_tm->tm_sec == 0 && !have_retried) {
 155                 have_retried = 1;
 156                 goto retry_get_time;
 157         }
 158
 159         rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
 160         rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
 161         rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
 162         rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
 163         rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
 164         rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
 165
 166         s3c_rtc_disable_clk(info);
 167
 168         rtc_tm->tm_year += 100;
 169         rtc_tm->tm_mon -= 1;
 170
 171         dev_dbg(dev, "read time %ptR\n", rtc_tm);
 172         return 0;
 173 }
 174
 175 static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm)
 176 {
 177         struct s3c_rtc *info = dev_get_drvdata(dev);
 178         int year = tm->tm_year - 100;
 179         int ret;
 180
 181         dev_dbg(dev, "set time %ptR\n", tm);
 182
 183         /* we get around y2k by simply not supporting it */
 184
 185         if (year < 0 || year >= 100) {
 186                 dev_err(dev, "rtc only supports 100 years\n");
 187                 return -EINVAL;
 188         }
 189
 190         ret = s3c_rtc_enable_clk(info);
 191         if (ret)
 192                 return ret;
 193
 194         writeb(bin2bcd(tm->tm_sec),  info->base + S3C2410_RTCSEC);
 195         writeb(bin2bcd(tm->tm_min),  info->base + S3C2410_RTCMIN);
 196         writeb(bin2bcd(tm->tm_hour), info->base + S3C2410_RTCHOUR);
 197         writeb(bin2bcd(tm->tm_mday), info->base + S3C2410_RTCDATE);
 198         writeb(bin2bcd(tm->tm_mon + 1), info->base + S3C2410_RTCMON);
 199         writeb(bin2bcd(year), info->base + S3C2410_RTCYEAR);
 200
 201         s3c_rtc_disable_clk(info);
 202
 203         return 0;
 204 }
 205
 206 static int s3c_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
 207 {
 208         struct s3c_rtc *info = dev_get_drvdata(dev);
 209         struct rtc_time *alm_tm = &alrm->time;
 210         unsigned int alm_en;
 211         int ret;
 212
 213         ret = s3c_rtc_enable_clk(info);
 214         if (ret)
 215                 return ret;
 216
 217         alm_tm->tm_sec  = readb(info->base + S3C2410_ALMSEC);
 218         alm_tm->tm_min  = readb(info->base + S3C2410_ALMMIN);
 219         alm_tm->tm_hour = readb(info->base + S3C2410_ALMHOUR);
 220         alm_tm->tm_mon  = readb(info->base + S3C2410_ALMMON);
 221         alm_tm->tm_mday = readb(info->base + S3C2410_ALMDATE);
 222         alm_tm->tm_year = readb(info->base + S3C2410_ALMYEAR);
 223
 224         alm_en = readb(info->base + S3C2410_RTCALM);
 225
 226         s3c_rtc_disable_clk(info);
 227
 228         alrm->enabled = (alm_en & S3C2410_RTCALM_ALMEN) ? 1 : 0;
 229
 230         dev_dbg(dev, "read alarm %d, %ptR\n", alm_en, alm_tm);
 231
 232         /* decode the alarm enable field */
 233         if (alm_en & S3C2410_RTCALM_SECEN)
 234                 alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec);
 235
 236         if (alm_en & S3C2410_RTCALM_MINEN)
 237                 alm_tm->tm_min = bcd2bin(alm_tm->tm_min);
 238
 239         if (alm_en & S3C2410_RTCALM_HOUREN)
 240                 alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour);
 241
 242         if (alm_en & S3C2410_RTCALM_DAYEN)
 243                 alm_tm->tm_mday = bcd2bin(alm_tm->tm_mday);
 244
 245         if (alm_en & S3C2410_RTCALM_MONEN) {
 246                 alm_tm->tm_mon = bcd2bin(alm_tm->tm_mon);
 247                 alm_tm->tm_mon -= 1;
 248         }
 249
 250         if (alm_en & S3C2410_RTCALM_YEAREN)
 251                 alm_tm->tm_year = bcd2bin(alm_tm->tm_year);
 252
 253         return 0;
 254 }
 255
 256 static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 257 {
 258         struct s3c_rtc *info = dev_get_drvdata(dev);
 259         struct rtc_time *tm = &alrm->time;
 260         unsigned int alrm_en;
 261         int ret;
 262
 263         dev_dbg(dev, "s3c_rtc_setalarm: %d, %ptR\n", alrm->enabled, tm);
 264
 265         ret = s3c_rtc_enable_clk(info);
 266         if (ret)
 267                 return ret;
 268
 269         alrm_en = readb(info->base + S3C2410_RTCALM) & S3C2410_RTCALM_ALMEN;
 270         writeb(0x00, info->base + S3C2410_RTCALM);
 271
 272         if (tm->tm_sec < 60 && tm->tm_sec >= 0) {
 273                 alrm_en |= S3C2410_RTCALM_SECEN;
 274                 writeb(bin2bcd(tm->tm_sec), info->base + S3C2410_ALMSEC);
 275         }
 276
 277         if (tm->tm_min < 60 && tm->tm_min >= 0) {
 278                 alrm_en |= S3C2410_RTCALM_MINEN;
 279                 writeb(bin2bcd(tm->tm_min), info->base + S3C2410_ALMMIN);
 280         }
 281
 282         if (tm->tm_hour < 24 && tm->tm_hour >= 0) {
 283                 alrm_en |= S3C2410_RTCALM_HOUREN;
 284                 writeb(bin2bcd(tm->tm_hour), info->base + S3C2410_ALMHOUR);
 285         }
 286
 287         if (tm->tm_mon < 12 && tm->tm_mon >= 0) {
 288                 alrm_en |= S3C2410_RTCALM_MONEN;
 289                 writeb(bin2bcd(tm->tm_mon + 1), info->base + S3C2410_ALMMON);
 290         }
 291
 292         if (tm->tm_mday <= 31 && tm->tm_mday >= 1) {
 293                 alrm_en |= S3C2410_RTCALM_DAYEN;
 294                 writeb(bin2bcd(tm->tm_mday), info->base + S3C2410_ALMDATE);
 295         }
 296
 297         dev_dbg(dev, "setting S3C2410_RTCALM to %08x\n", alrm_en);
 298
 299         writeb(alrm_en, info->base + S3C2410_RTCALM);
 300
 301         s3c_rtc_setaie(dev, alrm->enabled);
 302
 303         s3c_rtc_disable_clk(info);
 304
 305         return 0;
 306 }
 307
 308 static const struct rtc_class_ops s3c_rtcops = {
 309         .read_time      = s3c_rtc_gettime,
 310         .set_time       = s3c_rtc_settime,
 311         .read_alarm     = s3c_rtc_getalarm,
 312         .set_alarm      = s3c_rtc_setalarm,
 313         .alarm_irq_enable = s3c_rtc_setaie,
 314 };
 315
 316 static void s3c24xx_rtc_enable(struct s3c_rtc *info)
 317 {
 318         unsigned int con, tmp;
 319
 320         con = readw(info->base + S3C2410_RTCCON);
 321         /* re-enable the device, and check it is ok */
 322         if ((con & S3C2410_RTCCON_RTCEN) == 0) {
 323                 dev_info(info->dev, "rtc disabled, re-enabling\n");
 324
 325                 tmp = readw(info->base + S3C2410_RTCCON);
 326                 writew(tmp | S3C2410_RTCCON_RTCEN, info->base + S3C2410_RTCCON);
 327         }
 328
 329         if (con & S3C2410_RTCCON_CNTSEL) {
 330                 dev_info(info->dev, "removing RTCCON_CNTSEL\n");
 331
 332                 tmp = readw(info->base + S3C2410_RTCCON);
 333                 writew(tmp & ~S3C2410_RTCCON_CNTSEL,
 334                        info->base + S3C2410_RTCCON);
 335         }
 336
 337         if (con & S3C2410_RTCCON_CLKRST) {
 338                 dev_info(info->dev, "removing RTCCON_CLKRST\n");
 339
 340                 tmp = readw(info->base + S3C2410_RTCCON);
 341                 writew(tmp & ~S3C2410_RTCCON_CLKRST,
 342                        info->base + S3C2410_RTCCON);
 343         }
 344 }
 345
 346 static void s3c24xx_rtc_disable(struct s3c_rtc *info)
 347 {
 348         unsigned int con;
 349
 350         con = readw(info->base + S3C2410_RTCCON);
 351         con &= ~S3C2410_RTCCON_RTCEN;
 352         writew(con, info->base + S3C2410_RTCCON);
 353
 354         con = readb(info->base + S3C2410_TICNT);
 355         con &= ~S3C2410_TICNT_ENABLE;
 356         writeb(con, info->base + S3C2410_TICNT);
 357 }
 358
 359 static void s3c6410_rtc_disable(struct s3c_rtc *info)
 360 {
 361         unsigned int con;
 362
 363         con = readw(info->base + S3C2410_RTCCON);
 364         con &= ~S3C64XX_RTCCON_TICEN;
 365         con &= ~S3C2410_RTCCON_RTCEN;
 366         writew(con, info->base + S3C2410_RTCCON);
 367 }
 368
 369 static int s3c_rtc_remove(struct platform_device *pdev)
 370 {
 371         struct s3c_rtc *info = platform_get_drvdata(pdev);
 372
 373         s3c_rtc_setaie(info->dev, 0);
 374
 375         if (info->data->needs_src_clk)
 376                 clk_unprepare(info->rtc_src_clk);
 377         clk_unprepare(info->rtc_clk);
 378
 379         return 0;
 380 }
 381
 382 static int s3c_rtc_probe(struct platform_device *pdev)
 383 {
 384         struct s3c_rtc *info = NULL;
 385         int ret;
 386
 387         info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
 388         if (!info)
 389                 return -ENOMEM;
 390
 391         info->dev = &pdev->dev;
 392         info->data = of_device_get_match_data(&pdev->dev);
 393         if (!info->data) {
 394                 dev_err(&pdev->dev, "failed getting s3c_rtc_data\n");
 395                 return -EINVAL;
 396         }
 397         spin_lock_init(&info->alarm_lock);
 398
 399         platform_set_drvdata(pdev, info);
 400
 401         info->irq_alarm = platform_get_irq(pdev, 0);
 402         if (info->irq_alarm < 0)
 403                 return info->irq_alarm;
 404
 405         dev_dbg(&pdev->dev, "s3c2410_rtc: alarm irq %d\n", info->irq_alarm);
 406
 407         /* get the memory region */
 408         info->base = devm_platform_ioremap_resource(pdev, 0);
 409         if (IS_ERR(info->base))
 410                 return PTR_ERR(info->base);
 411
 412         info->rtc_clk = devm_clk_get(&pdev->dev, "rtc");
 413         if (IS_ERR(info->rtc_clk)) {
 414                 ret = PTR_ERR(info->rtc_clk);
 415                 if (ret != -EPROBE_DEFER)
 416                         dev_err(&pdev->dev, "failed to find rtc clock\n");
 417                 else
 418                         dev_dbg(&pdev->dev, "probe deferred due to missing rtc clk\n");
 419                 return ret;
 420         }
 421         ret = clk_prepare_enable(info->rtc_clk);
 422         if (ret)
 423                 return ret;
 424
 425         if (info->data->needs_src_clk) {
 426                 info->rtc_src_clk = devm_clk_get(&pdev->dev, "rtc_src");
 427                 if (IS_ERR(info->rtc_src_clk)) {
 428                         ret = dev_err_probe(&pdev->dev, PTR_ERR(info->rtc_src_clk),
 429                                             "failed to find rtc source clock\n");
 430                         goto err_src_clk;
 431                 }
 432                 ret = clk_prepare_enable(info->rtc_src_clk);
 433                 if (ret)
 434                         goto err_src_clk;
 435         }
 436
 437         /* disable RTC enable bits potentially set by the bootloader */
 438         if (info->data->disable)
 439                 info->data->disable(info);
 440
 441         /* check to see if everything is setup correctly */
 442         if (info->data->enable)
 443                 info->data->enable(info);
 444
 445         dev_dbg(&pdev->dev, "s3c2410_rtc: RTCCON=%02x\n",
 446                 readw(info->base + S3C2410_RTCCON));
 447
 448         device_init_wakeup(&pdev->dev, 1);
 449
 450         /* register RTC and exit */
 451         info->rtc = devm_rtc_device_register(&pdev->dev, "s3c", &s3c_rtcops,
 452                                              THIS_MODULE);
 453         if (IS_ERR(info->rtc)) {
 454                 dev_err(&pdev->dev, "cannot attach rtc\n");
 455                 ret = PTR_ERR(info->rtc);
 456                 goto err_nortc;
 457         }
 458
 459         ret = devm_request_irq(&pdev->dev, info->irq_alarm, s3c_rtc_alarmirq,
 460                                0, "s3c2410-rtc alarm", info);
 461         if (ret) {
 462                 dev_err(&pdev->dev, "IRQ%d error %d\n", info->irq_alarm, ret);
 463                 goto err_nortc;
 464         }
 465
 466         s3c_rtc_disable_clk(info);
 467
 468         return 0;
 469
 470 err_nortc:
 471         if (info->data->disable)
 472                 info->data->disable(info);
 473
 474         if (info->data->needs_src_clk)
 475                 clk_disable_unprepare(info->rtc_src_clk);
 476 err_src_clk:
 477         clk_disable_unprepare(info->rtc_clk);
 478
 479         return ret;
 480 }
 481
 482 #ifdef CONFIG_PM_SLEEP
 483
 484 static int s3c_rtc_suspend(struct device *dev)
 485 {
 486         struct s3c_rtc *info = dev_get_drvdata(dev);
 487         int ret;
 488
 489         ret = s3c_rtc_enable_clk(info);
 490         if (ret)
 491                 return ret;
 492
 493         if (info->data->disable)
 494                 info->data->disable(info);
 495
 496         if (device_may_wakeup(dev) && !info->wake_en) {
 497                 if (enable_irq_wake(info->irq_alarm) == 0)
 498                         info->wake_en = true;
 499                 else
 500                         dev_err(dev, "enable_irq_wake failed\n");
 501         }
 502
 503         return 0;
 504 }
 505
 506 static int s3c_rtc_resume(struct device *dev)
 507 {
 508         struct s3c_rtc *info = dev_get_drvdata(dev);
 509
 510         if (info->data->enable)
 511                 info->data->enable(info);
 512
 513         s3c_rtc_disable_clk(info);
 514
 515         if (device_may_wakeup(dev) && info->wake_en) {
 516                 disable_irq_wake(info->irq_alarm);
 517                 info->wake_en = false;
 518         }
 519
 520         return 0;
 521 }
 522 #endif
 523 static SIMPLE_DEV_PM_OPS(s3c_rtc_pm_ops, s3c_rtc_suspend, s3c_rtc_resume);
 524
 525 static void s3c24xx_rtc_irq(struct s3c_rtc *info, int mask)
 526 {
 527         rtc_update_irq(info->rtc, 1, RTC_AF | RTC_IRQF);
 528 }
 529
 530 static void s3c6410_rtc_irq(struct s3c_rtc *info, int mask)
 531 {
 532         rtc_update_irq(info->rtc, 1, RTC_AF | RTC_IRQF);
 533         writeb(mask, info->base + S3C2410_INTP);
 534 }
 535
 536 static struct s3c_rtc_data const s3c2410_rtc_data = {
 537         .irq_handler            = s3c24xx_rtc_irq,
 538         .enable                 = s3c24xx_rtc_enable,
 539         .disable                = s3c24xx_rtc_disable,
 540 };
 541
 542 static struct s3c_rtc_data const s3c2416_rtc_data = {
 543         .irq_handler            = s3c24xx_rtc_irq,
 544         .enable                 = s3c24xx_rtc_enable,
 545         .disable                = s3c24xx_rtc_disable,
 546 };
 547
 548 static struct s3c_rtc_data const s3c2443_rtc_data = {
 549         .irq_handler            = s3c24xx_rtc_irq,
 550         .enable                 = s3c24xx_rtc_enable,
 551         .disable                = s3c24xx_rtc_disable,
 552 };
 553
 554 static struct s3c_rtc_data const s3c6410_rtc_data = {
 555         .needs_src_clk          = true,
 556         .irq_handler            = s3c6410_rtc_irq,
 557         .enable                 = s3c24xx_rtc_enable,
 558         .disable                = s3c6410_rtc_disable,
 559 };
 560
 561 static const __maybe_unused struct of_device_id s3c_rtc_dt_match[] = {
 562         {
 563                 .compatible = "samsung,s3c2410-rtc",
 564                 .data = &s3c2410_rtc_data,
 565         }, {
 566                 .compatible = "samsung,s3c2416-rtc",
 567                 .data = &s3c2416_rtc_data,
 568         }, {
 569                 .compatible = "samsung,s3c2443-rtc",
 570                 .data = &s3c2443_rtc_data,
 571         }, {
 572                 .compatible = "samsung,s3c6410-rtc",
 573                 .data = &s3c6410_rtc_data,
 574         }, {
 575                 .compatible = "samsung,exynos3250-rtc",
 576                 .data = &s3c6410_rtc_data,
 577         },
 578         { /* sentinel */ },
 579 };
 580 MODULE_DEVICE_TABLE(of, s3c_rtc_dt_match);
 581
 582 static struct platform_driver s3c_rtc_driver = {
 583         .probe          = s3c_rtc_probe,
 584         .remove         = s3c_rtc_remove,
 585         .driver         = {
 586                 .name   = "s3c-rtc",
 587                 .pm     = &s3c_rtc_pm_ops,
 588                 .of_match_table = of_match_ptr(s3c_rtc_dt_match),
 589         },
 590 };
 591 module_platform_driver(s3c_rtc_driver);
 592
 593 MODULE_DESCRIPTION("Samsung S3C RTC Driver");
 594 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 595 MODULE_LICENSE("GPL");
 596 MODULE_ALIAS("platform:s3c2410-rtc");