drivers/rtc/rtc-max77686.c

   1 /*
   2  * RTC driver for Maxim MAX77686
   3  *
   4  * Copyright (C) 2012 Samsung Electronics Co.Ltd
   5  *
   6  *  based on rtc-max8997.c
   7  *
   8  *  This program is free software; you can redistribute  it and/or modify it
   9  *  under  the terms of  the GNU General  Public License as published by the
  10  *  Free Software Foundation;  either version 2 of the  License, or (at your
  11  *  option) any later version.
  12  *
  13  */
  14
  15 #include <linux/slab.h>
  16 #include <linux/rtc.h>
  17 #include <linux/delay.h>
  18 #include <linux/mutex.h>
  19 #include <linux/module.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/mfd/max77686-private.h>
  22 #include <linux/irqdomain.h>
  23 #include <linux/regmap.h>
  24
  25 /* RTC Control Register */
  26 #define BCD_EN_SHIFT                    0
  27 #define BCD_EN_MASK                     (1 << BCD_EN_SHIFT)
  28 #define MODEL24_SHIFT                   1
  29 #define MODEL24_MASK                    (1 << MODEL24_SHIFT)
  30 /* RTC Update Register1 */
  31 #define RTC_UDR_SHIFT                   0
  32 #define RTC_UDR_MASK                    (1 << RTC_UDR_SHIFT)
  33 #define RTC_RBUDR_SHIFT                 4
  34 #define RTC_RBUDR_MASK                  (1 << RTC_RBUDR_SHIFT)
  35 /* WTSR and SMPL Register */
  36 #define WTSRT_SHIFT                     0
  37 #define SMPLT_SHIFT                     2
  38 #define WTSR_EN_SHIFT                   6
  39 #define SMPL_EN_SHIFT                   7
  40 #define WTSRT_MASK                      (3 << WTSRT_SHIFT)
  41 #define SMPLT_MASK                      (3 << SMPLT_SHIFT)
  42 #define WTSR_EN_MASK                    (1 << WTSR_EN_SHIFT)
  43 #define SMPL_EN_MASK                    (1 << SMPL_EN_SHIFT)
  44 /* RTC Hour register */
  45 #define HOUR_PM_SHIFT                   6
  46 #define HOUR_PM_MASK                    (1 << HOUR_PM_SHIFT)
  47 /* RTC Alarm Enable */
  48 #define ALARM_ENABLE_SHIFT              7
  49 #define ALARM_ENABLE_MASK               (1 << ALARM_ENABLE_SHIFT)
  50
  51 #define MAX77686_RTC_UPDATE_DELAY       16
  52 #undef MAX77686_RTC_WTSR_SMPL
  53
  54 enum {
  55         RTC_SEC = 0,
  56         RTC_MIN,
  57         RTC_HOUR,
  58         RTC_WEEKDAY,
  59         RTC_MONTH,
  60         RTC_YEAR,
  61         RTC_DATE,
  62         RTC_NR_TIME
  63 };
  64
  65 struct max77686_rtc_info {
  66         struct device           *dev;
  67         struct max77686_dev     *max77686;
  68         struct i2c_client       *rtc;
  69         struct rtc_device       *rtc_dev;
  70         struct mutex            lock;
  71
  72         struct regmap           *regmap;
  73
  74         int virq;
  75         int rtc_24hr_mode;
  76 };
  77
  78 enum MAX77686_RTC_OP {
  79         MAX77686_RTC_WRITE,
  80         MAX77686_RTC_READ,
  81 };
  82
  83 static inline int max77686_rtc_calculate_wday(u8 shifted)
  84 {
  85         int counter = -1;
  86         while (shifted) {
  87                 shifted >>= 1;
  88                 counter++;
  89         }
  90         return counter;
  91 }
  92
  93 static void max77686_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
  94                                    int rtc_24hr_mode)
  95 {
  96         tm->tm_sec = data[RTC_SEC] & 0x7f;
  97         tm->tm_min = data[RTC_MIN] & 0x7f;
  98         if (rtc_24hr_mode)
  99                 tm->tm_hour = data[RTC_HOUR] & 0x1f;
 100         else {
 101                 tm->tm_hour = data[RTC_HOUR] & 0x0f;
 102                 if (data[RTC_HOUR] & HOUR_PM_MASK)
 103                         tm->tm_hour += 12;
 104         }
 105
 106         tm->tm_wday = max77686_rtc_calculate_wday(data[RTC_WEEKDAY] & 0x7f);
 107         tm->tm_mday = data[RTC_DATE] & 0x1f;
 108         tm->tm_mon = (data[RTC_MONTH] & 0x0f) - 1;
 109         tm->tm_year = (data[RTC_YEAR] & 0x7f) + 100;
 110         tm->tm_yday = 0;
 111         tm->tm_isdst = 0;
 112 }
 113
 114 static int max77686_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
 115 {
 116         data[RTC_SEC] = tm->tm_sec;
 117         data[RTC_MIN] = tm->tm_min;
 118         data[RTC_HOUR] = tm->tm_hour;
 119         data[RTC_WEEKDAY] = 1 << tm->tm_wday;
 120         data[RTC_DATE] = tm->tm_mday;
 121         data[RTC_MONTH] = tm->tm_mon + 1;
 122         data[RTC_YEAR] = tm->tm_year > 100 ? (tm->tm_year - 100) : 0;
 123
 124         if (tm->tm_year < 100) {
 125                 pr_warn("%s: MAX77686 RTC cannot handle the year %d."
 126                         "Assume it's 2000.\n", __func__, 1900 + tm->tm_year);
 127                 return -EINVAL;
 128         }
 129         return 0;
 130 }
 131
 132 static int max77686_rtc_update(struct max77686_rtc_info *info,
 133         enum MAX77686_RTC_OP op)
 134 {
 135         int ret;
 136         unsigned int data;
 137
 138         if (op == MAX77686_RTC_WRITE)
 139                 data = 1 << RTC_UDR_SHIFT;
 140         else
 141                 data = 1 << RTC_RBUDR_SHIFT;
 142
 143         ret = regmap_update_bits(info->max77686->rtc_regmap,
 144                                  MAX77686_RTC_UPDATE0, data, data);
 145         if (ret < 0)
 146                 dev_err(info->dev, "%s: fail to write update reg(ret=%d, data=0x%x)\n",
 147                                 __func__, ret, data);
 148         else {
 149                 /* Minimum 16ms delay required before RTC update. */
 150                 msleep(MAX77686_RTC_UPDATE_DELAY);
 151         }
 152
 153         return ret;
 154 }
 155
 156 static int max77686_rtc_read_time(struct device *dev, struct rtc_time *tm)
 157 {
 158         struct max77686_rtc_info *info = dev_get_drvdata(dev);
 159         u8 data[RTC_NR_TIME];
 160         int ret;
 161
 162         mutex_lock(&info->lock);
 163
 164         ret = max77686_rtc_update(info, MAX77686_RTC_READ);
 165         if (ret < 0)
 166                 goto out;
 167
 168         ret = regmap_bulk_read(info->max77686->rtc_regmap,
 169                                 MAX77686_RTC_SEC, data, RTC_NR_TIME);
 170         if (ret < 0) {
 171                 dev_err(info->dev, "%s: fail to read time reg(%d)\n", __func__, ret);
 172                 goto out;
 173         }
 174
 175         max77686_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);
 176
 177         ret = rtc_valid_tm(tm);
 178
 179 out:
 180         mutex_unlock(&info->lock);
 181         return ret;
 182 }
 183
 184 static int max77686_rtc_set_time(struct device *dev, struct rtc_time *tm)
 185 {
 186         struct max77686_rtc_info *info = dev_get_drvdata(dev);
 187         u8 data[RTC_NR_TIME];
 188         int ret;
 189
 190         ret = max77686_rtc_tm_to_data(tm, data);
 191         if (ret < 0)
 192                 return ret;
 193
 194         mutex_lock(&info->lock);
 195
 196         ret = regmap_bulk_write(info->max77686->rtc_regmap,
 197                                  MAX77686_RTC_SEC, data, RTC_NR_TIME);
 198         if (ret < 0) {
 199                 dev_err(info->dev, "%s: fail to write time reg(%d)\n", __func__,
 200                                 ret);
 201                 goto out;
 202         }
 203
 204         ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
 205
 206 out:
 207         mutex_unlock(&info->lock);
 208         return ret;
 209 }
 210
 211 static int max77686_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 212 {
 213         struct max77686_rtc_info *info = dev_get_drvdata(dev);
 214         u8 data[RTC_NR_TIME];
 215         unsigned int val;
 216         int i, ret;
 217
 218         mutex_lock(&info->lock);
 219
 220         ret = max77686_rtc_update(info, MAX77686_RTC_READ);
 221         if (ret < 0)
 222                 goto out;
 223
 224         ret = regmap_bulk_read(info->max77686->rtc_regmap,
 225                                  MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
 226         if (ret < 0) {
 227                 dev_err(info->dev, "%s:%d fail to read alarm reg(%d)\n",
 228                                 __func__, __LINE__, ret);
 229                 goto out;
 230         }
 231
 232         max77686_rtc_data_to_tm(data, &alrm->time, info->rtc_24hr_mode);
 233
 234         alrm->enabled = 0;
 235         for (i = 0; i < RTC_NR_TIME; i++) {
 236                 if (data[i] & ALARM_ENABLE_MASK) {
 237                         alrm->enabled = 1;
 238                         break;
 239                 }
 240         }
 241
 242         alrm->pending = 0;
 243         ret = regmap_read(info->max77686->regmap, MAX77686_REG_STATUS2, &val);
 244         if (ret < 0) {
 245                 dev_err(info->dev, "%s:%d fail to read status2 reg(%d)\n",
 246                                 __func__, __LINE__, ret);
 247                 goto out;
 248         }
 249
 250         if (val & (1 << 4)) /* RTCA1 */
 251                 alrm->pending = 1;
 252
 253 out:
 254         mutex_unlock(&info->lock);
 255         return 0;
 256 }
 257
 258 static int max77686_rtc_stop_alarm(struct max77686_rtc_info *info)
 259 {
 260         u8 data[RTC_NR_TIME];
 261         int ret, i;
 262         struct rtc_time tm;
 263
 264         if (!mutex_is_locked(&info->lock))
 265                 dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
 266
 267         ret = max77686_rtc_update(info, MAX77686_RTC_READ);
 268         if (ret < 0)
 269                 goto out;
 270
 271         ret = regmap_bulk_read(info->max77686->rtc_regmap,
 272                                  MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
 273         if (ret < 0) {
 274                 dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
 275                                 __func__, ret);
 276                 goto out;
 277         }
 278
 279         max77686_rtc_data_to_tm(data, &tm, info->rtc_24hr_mode);
 280
 281         for (i = 0; i < RTC_NR_TIME; i++)
 282                 data[i] &= ~ALARM_ENABLE_MASK;
 283
 284         ret = regmap_bulk_write(info->max77686->rtc_regmap,
 285                                  MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
 286         if (ret < 0) {
 287                 dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
 288                                 __func__, ret);
 289                 goto out;
 290         }
 291
 292         ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
 293 out:
 294         return ret;
 295 }
 296
 297 static int max77686_rtc_start_alarm(struct max77686_rtc_info *info)
 298 {
 299         u8 data[RTC_NR_TIME];
 300         int ret;
 301         struct rtc_time tm;
 302
 303         if (!mutex_is_locked(&info->lock))
 304                 dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
 305
 306         ret = max77686_rtc_update(info, MAX77686_RTC_READ);
 307         if (ret < 0)
 308                 goto out;
 309
 310         ret = regmap_bulk_read(info->max77686->rtc_regmap,
 311                                  MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
 312         if (ret < 0) {
 313                 dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
 314                                 __func__, ret);
 315                 goto out;
 316         }
 317
 318         max77686_rtc_data_to_tm(data, &tm, info->rtc_24hr_mode);
 319
 320         data[RTC_SEC] |= (1 << ALARM_ENABLE_SHIFT);
 321         data[RTC_MIN] |= (1 << ALARM_ENABLE_SHIFT);
 322         data[RTC_HOUR] |= (1 << ALARM_ENABLE_SHIFT);
 323         data[RTC_WEEKDAY] &= ~ALARM_ENABLE_MASK;
 324         if (data[RTC_MONTH] & 0xf)
 325                 data[RTC_MONTH] |= (1 << ALARM_ENABLE_SHIFT);
 326         if (data[RTC_YEAR] & 0x7f)
 327                 data[RTC_YEAR] |= (1 << ALARM_ENABLE_SHIFT);
 328         if (data[RTC_DATE] & 0x1f)
 329                 data[RTC_DATE] |= (1 << ALARM_ENABLE_SHIFT);
 330
 331         ret = regmap_bulk_write(info->max77686->rtc_regmap,
 332                                  MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
 333         if (ret < 0) {
 334                 dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
 335                                 __func__, ret);
 336                 goto out;
 337         }
 338
 339         ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
 340 out:
 341         return ret;
 342 }
 343
 344 static int max77686_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 345 {
 346         struct max77686_rtc_info *info = dev_get_drvdata(dev);
 347         u8 data[RTC_NR_TIME];
 348         int ret;
 349
 350         ret = max77686_rtc_tm_to_data(&alrm->time, data);
 351         if (ret < 0)
 352                 return ret;
 353
 354         mutex_lock(&info->lock);
 355
 356         ret = max77686_rtc_stop_alarm(info);
 357         if (ret < 0)
 358                 goto out;
 359
 360         ret = regmap_bulk_write(info->max77686->rtc_regmap,
 361                                  MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
 362
 363         if (ret < 0) {
 364                 dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
 365                                 __func__, ret);
 366                 goto out;
 367         }
 368
 369         ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
 370         if (ret < 0)
 371                 goto out;
 372
 373         if (alrm->enabled)
 374                 ret = max77686_rtc_start_alarm(info);
 375 out:
 376         mutex_unlock(&info->lock);
 377         return ret;
 378 }
 379
 380 static int max77686_rtc_alarm_irq_enable(struct device *dev,
 381                                         unsigned int enabled)
 382 {
 383         struct max77686_rtc_info *info = dev_get_drvdata(dev);
 384         int ret;
 385
 386         mutex_lock(&info->lock);
 387         if (enabled)
 388                 ret = max77686_rtc_start_alarm(info);
 389         else
 390                 ret = max77686_rtc_stop_alarm(info);
 391         mutex_unlock(&info->lock);
 392
 393         return ret;
 394 }
 395
 396 static irqreturn_t max77686_rtc_alarm_irq(int irq, void *data)
 397 {
 398         struct max77686_rtc_info *info = data;
 399
 400         dev_info(info->dev, "%s:irq(%d)\n", __func__, irq);
 401
 402         rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
 403
 404         return IRQ_HANDLED;
 405 }
 406
 407 static const struct rtc_class_ops max77686_rtc_ops = {
 408         .read_time = max77686_rtc_read_time,
 409         .set_time = max77686_rtc_set_time,
 410         .read_alarm = max77686_rtc_read_alarm,
 411         .set_alarm = max77686_rtc_set_alarm,
 412         .alarm_irq_enable = max77686_rtc_alarm_irq_enable,
 413 };
 414
 415 #ifdef MAX77686_RTC_WTSR_SMPL
 416 static void max77686_rtc_enable_wtsr(struct max77686_rtc_info *info, bool enable)
 417 {
 418         int ret;
 419         unsigned int val, mask;
 420
 421         if (enable)
 422                 val = (1 << WTSR_EN_SHIFT) | (3 << WTSRT_SHIFT);
 423         else
 424                 val = 0;
 425
 426         mask = WTSR_EN_MASK | WTSRT_MASK;
 427
 428         dev_info(info->dev, "%s: %s WTSR\n", __func__,
 429                         enable ? "enable" : "disable");
 430
 431         ret = regmap_update_bits(info->max77686->rtc_regmap,
 432                                  MAX77686_WTSR_SMPL_CNTL, mask, val);
 433         if (ret < 0) {
 434                 dev_err(info->dev, "%s: fail to update WTSR reg(%d)\n",
 435                                 __func__, ret);
 436                 return;
 437         }
 438
 439         max77686_rtc_update(info, MAX77686_RTC_WRITE);
 440 }
 441
 442 static void max77686_rtc_enable_smpl(struct max77686_rtc_info *info, bool enable)
 443 {
 444         int ret;
 445         unsigned int val, mask;
 446
 447         if (enable)
 448                 val = (1 << SMPL_EN_SHIFT) | (0 << SMPLT_SHIFT);
 449         else
 450                 val = 0;
 451
 452         mask = SMPL_EN_MASK | SMPLT_MASK;
 453
 454         dev_info(info->dev, "%s: %s SMPL\n", __func__,
 455                         enable ? "enable" : "disable");
 456
 457         ret = regmap_update_bits(info->max77686->rtc_regmap,
 458                                  MAX77686_WTSR_SMPL_CNTL, mask, val);
 459         if (ret < 0) {
 460                 dev_err(info->dev, "%s: fail to update SMPL reg(%d)\n",
 461                                 __func__, ret);
 462                 return;
 463         }
 464
 465         max77686_rtc_update(info, MAX77686_RTC_WRITE);
 466
 467         val = 0;
 468         regmap_read(info->max77686->rtc_regmap, MAX77686_WTSR_SMPL_CNTL, &val);
 469         dev_info(info->dev, "%s: WTSR_SMPL(0x%02x)\n", __func__, val);
 470 }
 471 #endif /* MAX77686_RTC_WTSR_SMPL */
 472
 473 static int max77686_rtc_init_reg(struct max77686_rtc_info *info)
 474 {
 475         u8 data[2];
 476         int ret;
 477
 478         /* Set RTC control register : Binary mode, 24hour mdoe */
 479         data[0] = (1 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
 480         data[1] = (0 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
 481
 482         info->rtc_24hr_mode = 1;
 483
 484         ret = regmap_bulk_write(info->max77686->rtc_regmap, MAX77686_RTC_CONTROLM, data, 2);
 485         if (ret < 0) {
 486                 dev_err(info->dev, "%s: fail to write controlm reg(%d)\n",
 487                                 __func__, ret);
 488                 return ret;
 489         }
 490
 491         ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
 492         return ret;
 493 }
 494
 495 static int max77686_rtc_probe(struct platform_device *pdev)
 496 {
 497         struct max77686_dev *max77686 = dev_get_drvdata(pdev->dev.parent);
 498         struct max77686_rtc_info *info;
 499         int ret;
 500
 501         dev_info(&pdev->dev, "%s\n", __func__);
 502
 503         info = devm_kzalloc(&pdev->dev, sizeof(struct max77686_rtc_info),
 504                                 GFP_KERNEL);
 505         if (!info)
 506                 return -ENOMEM;
 507
 508         mutex_init(&info->lock);
 509         info->dev = &pdev->dev;
 510         info->max77686 = max77686;
 511         info->rtc = max77686->rtc;
 512
 513         platform_set_drvdata(pdev, info);
 514
 515         ret = max77686_rtc_init_reg(info);
 516
 517         if (ret < 0) {
 518                 dev_err(&pdev->dev, "Failed to initialize RTC reg:%d\n", ret);
 519                 goto err_rtc;
 520         }
 521
 522 #ifdef MAX77686_RTC_WTSR_SMPL
 523         max77686_rtc_enable_wtsr(info, true);
 524         max77686_rtc_enable_smpl(info, true);
 525 #endif
 526
 527         device_init_wakeup(&pdev->dev, 1);
 528
 529         info->rtc_dev = devm_rtc_device_register(&pdev->dev, "max77686-rtc",
 530                                         &max77686_rtc_ops, THIS_MODULE);
 531
 532         if (IS_ERR(info->rtc_dev)) {
 533                 dev_info(&pdev->dev, "%s: fail\n", __func__);
 534
 535                 ret = PTR_ERR(info->rtc_dev);
 536                 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
 537                 if (ret == 0)
 538                         ret = -EINVAL;
 539                 goto err_rtc;
 540         }
 541
 542         info->virq = regmap_irq_get_virq(max77686->rtc_irq_data,
 543                                          MAX77686_RTCIRQ_RTCA1);
 544         if (!info->virq) {
 545                 ret = -ENXIO;
 546                 goto err_rtc;
 547         }
 548
 549         ret = devm_request_threaded_irq(&pdev->dev, info->virq, NULL,
 550                                 max77686_rtc_alarm_irq, 0, "rtc-alarm1", info);
 551         if (ret < 0)
 552                 dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
 553                         info->virq, ret);
 554
 555 err_rtc:
 556         return ret;
 557 }
 558
 559 static void max77686_rtc_shutdown(struct platform_device *pdev)
 560 {
 561 #ifdef MAX77686_RTC_WTSR_SMPL
 562         struct max77686_rtc_info *info = platform_get_drvdata(pdev);
 563         int i;
 564         u8 val = 0;
 565
 566         for (i = 0; i < 3; i++) {
 567                 max77686_rtc_enable_wtsr(info, false);
 568                 regmap_read(info->max77686->rtc_regmap, MAX77686_WTSR_SMPL_CNTL, &val);
 569                 dev_info(info->dev, "%s: WTSR_SMPL reg(0x%02x)\n", __func__,
 570                                 val);
 571                 if (val & WTSR_EN_MASK) {
 572                         dev_emerg(info->dev, "%s: fail to disable WTSR\n",
 573                                         __func__);
 574                 } else {
 575                         dev_info(info->dev, "%s: success to disable WTSR\n",
 576                                         __func__);
 577                         break;
 578                 }
 579         }
 580
 581         /* Disable SMPL when power off */
 582         max77686_rtc_enable_smpl(info, false);
 583 #endif /* MAX77686_RTC_WTSR_SMPL */
 584 }
 585
 586 static const struct platform_device_id rtc_id[] = {
 587         { "max77686-rtc", 0 },
 588         {},
 589 };
 590
 591 static struct platform_driver max77686_rtc_driver = {
 592         .driver         = {
 593                 .name   = "max77686-rtc",
 594                 .owner  = THIS_MODULE,
 595         },
 596         .probe          = max77686_rtc_probe,
 597         .shutdown       = max77686_rtc_shutdown,
 598         .id_table       = rtc_id,
 599 };
 600
 601 module_platform_driver(max77686_rtc_driver);
 602
 603 MODULE_DESCRIPTION("Maxim MAX77686 RTC driver");
 604 MODULE_AUTHOR("Chiwoong Byun <woong.byun@samsung.com>");
 605 MODULE_LICENSE("GPL");