drivers/rtc/rtc-max8997.c

   1 /*
   2  * RTC driver for Maxim MAX8997
   3  *
   4  * Copyright (C) 2013 Samsung Electronics Co.Ltd
   5  *
   6  *  based on rtc-max8998.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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  16
  17 #include <linux/slab.h>
  18 #include <linux/rtc.h>
  19 #include <linux/delay.h>
  20 #include <linux/mutex.h>
  21 #include <linux/module.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/mfd/max8997-private.h>
  24 #include <linux/irqdomain.h>
  25
  26 /* Module parameter for WTSR function control */
  27 static int wtsr_en = 1;
  28 module_param(wtsr_en, int, 0444);
  29 MODULE_PARM_DESC(wtsr_en, "Watchdog Timeout & Software Reset (default=on)");
  30 /* Module parameter for SMPL function control */
  31 static int smpl_en = 1;
  32 module_param(smpl_en, int, 0444);
  33 MODULE_PARM_DESC(smpl_en, "Sudden Momentary Power Loss (default=on)");
  34
  35 /* RTC Control Register */
  36 #define BCD_EN_SHIFT                    0
  37 #define BCD_EN_MASK                     (1 << BCD_EN_SHIFT)
  38 #define MODEL24_SHIFT                   1
  39 #define MODEL24_MASK                    (1 << MODEL24_SHIFT)
  40 /* RTC Update Register1 */
  41 #define RTC_UDR_SHIFT                   0
  42 #define RTC_UDR_MASK                    (1 << RTC_UDR_SHIFT)
  43 /* WTSR and SMPL Register */
  44 #define WTSRT_SHIFT                     0
  45 #define SMPLT_SHIFT                     2
  46 #define WTSR_EN_SHIFT                   6
  47 #define SMPL_EN_SHIFT                   7
  48 #define WTSRT_MASK                      (3 << WTSRT_SHIFT)
  49 #define SMPLT_MASK                      (3 << SMPLT_SHIFT)
  50 #define WTSR_EN_MASK                    (1 << WTSR_EN_SHIFT)
  51 #define SMPL_EN_MASK                    (1 << SMPL_EN_SHIFT)
  52 /* RTC Hour register */
  53 #define HOUR_PM_SHIFT                   6
  54 #define HOUR_PM_MASK                    (1 << HOUR_PM_SHIFT)
  55 /* RTC Alarm Enable */
  56 #define ALARM_ENABLE_SHIFT              7
  57 #define ALARM_ENABLE_MASK               (1 << ALARM_ENABLE_SHIFT)
  58
  59 enum {
  60         RTC_SEC = 0,
  61         RTC_MIN,
  62         RTC_HOUR,
  63         RTC_WEEKDAY,
  64         RTC_MONTH,
  65         RTC_YEAR,
  66         RTC_DATE,
  67         RTC_NR_TIME
  68 };
  69
  70 struct max8997_rtc_info {
  71         struct device           *dev;
  72         struct max8997_dev      *max8997;
  73         struct i2c_client       *rtc;
  74         struct rtc_device       *rtc_dev;
  75         struct mutex            lock;
  76         int virq;
  77         int rtc_24hr_mode;
  78 };
  79
  80 static void max8997_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
  81                                    int rtc_24hr_mode)
  82 {
  83         tm->tm_sec = data[RTC_SEC] & 0x7f;
  84         tm->tm_min = data[RTC_MIN] & 0x7f;
  85         if (rtc_24hr_mode)
  86                 tm->tm_hour = data[RTC_HOUR] & 0x1f;
  87         else {
  88                 tm->tm_hour = data[RTC_HOUR] & 0x0f;
  89                 if (data[RTC_HOUR] & HOUR_PM_MASK)
  90                         tm->tm_hour += 12;
  91         }
  92
  93         tm->tm_wday = fls(data[RTC_WEEKDAY] & 0x7f) - 1;
  94         tm->tm_mday = data[RTC_DATE] & 0x1f;
  95         tm->tm_mon = (data[RTC_MONTH] & 0x0f) - 1;
  96         tm->tm_year = (data[RTC_YEAR] & 0x7f) + 100;
  97         tm->tm_yday = 0;
  98         tm->tm_isdst = 0;
  99 }
 100
 101 static int max8997_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
 102 {
 103         data[RTC_SEC] = tm->tm_sec;
 104         data[RTC_MIN] = tm->tm_min;
 105         data[RTC_HOUR] = tm->tm_hour;
 106         data[RTC_WEEKDAY] = 1 << tm->tm_wday;
 107         data[RTC_DATE] = tm->tm_mday;
 108         data[RTC_MONTH] = tm->tm_mon + 1;
 109         data[RTC_YEAR] = tm->tm_year > 100 ? (tm->tm_year - 100) : 0;
 110
 111         if (tm->tm_year < 100) {
 112                 pr_warn("RTC cannot handle the year %d.  Assume it's 2000.\n",
 113                         1900 + tm->tm_year);
 114                 return -EINVAL;
 115         }
 116         return 0;
 117 }
 118
 119 static inline int max8997_rtc_set_update_reg(struct max8997_rtc_info *info)
 120 {
 121         int ret;
 122
 123         ret = max8997_write_reg(info->rtc, MAX8997_RTC_UPDATE1,
 124                                                 RTC_UDR_MASK);
 125         if (ret < 0)
 126                 dev_err(info->dev, "%s: fail to write update reg(%d)\n",
 127                                 __func__, ret);
 128         else {
 129                 /* Minimum 16ms delay required before RTC update.
 130                  * Otherwise, we may read and update based on out-of-date
 131                  * value */
 132                 msleep(20);
 133         }
 134
 135         return ret;
 136 }
 137
 138 static int max8997_rtc_read_time(struct device *dev, struct rtc_time *tm)
 139 {
 140         struct max8997_rtc_info *info = dev_get_drvdata(dev);
 141         u8 data[RTC_NR_TIME];
 142         int ret;
 143
 144         mutex_lock(&info->lock);
 145         ret = max8997_bulk_read(info->rtc, MAX8997_RTC_SEC, RTC_NR_TIME, data);
 146         mutex_unlock(&info->lock);
 147
 148         if (ret < 0) {
 149                 dev_err(info->dev, "%s: fail to read time reg(%d)\n", __func__,
 150                                 ret);
 151                 return ret;
 152         }
 153
 154         max8997_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);
 155
 156         return rtc_valid_tm(tm);
 157 }
 158
 159 static int max8997_rtc_set_time(struct device *dev, struct rtc_time *tm)
 160 {
 161         struct max8997_rtc_info *info = dev_get_drvdata(dev);
 162         u8 data[RTC_NR_TIME];
 163         int ret;
 164
 165         ret = max8997_rtc_tm_to_data(tm, data);
 166         if (ret < 0)
 167                 return ret;
 168
 169         mutex_lock(&info->lock);
 170
 171         ret = max8997_bulk_write(info->rtc, MAX8997_RTC_SEC, RTC_NR_TIME, data);
 172         if (ret < 0) {
 173                 dev_err(info->dev, "%s: fail to write time reg(%d)\n", __func__,
 174                                 ret);
 175                 goto out;
 176         }
 177
 178         ret = max8997_rtc_set_update_reg(info);
 179 out:
 180         mutex_unlock(&info->lock);
 181         return ret;
 182 }
 183
 184 static int max8997_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 185 {
 186         struct max8997_rtc_info *info = dev_get_drvdata(dev);
 187         u8 data[RTC_NR_TIME];
 188         u8 val;
 189         int i, ret;
 190
 191         mutex_lock(&info->lock);
 192
 193         ret = max8997_bulk_read(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
 194                         data);
 195         if (ret < 0) {
 196                 dev_err(info->dev, "%s:%d fail to read alarm reg(%d)\n",
 197                                 __func__, __LINE__, ret);
 198                 goto out;
 199         }
 200
 201         max8997_rtc_data_to_tm(data, &alrm->time, info->rtc_24hr_mode);
 202
 203         alrm->enabled = 0;
 204         for (i = 0; i < RTC_NR_TIME; i++) {
 205                 if (data[i] & ALARM_ENABLE_MASK) {
 206                         alrm->enabled = 1;
 207                         break;
 208                 }
 209         }
 210
 211         alrm->pending = 0;
 212         ret = max8997_read_reg(info->max8997->i2c, MAX8997_REG_STATUS1, &val);
 213         if (ret < 0) {
 214                 dev_err(info->dev, "%s:%d fail to read status1 reg(%d)\n",
 215                                 __func__, __LINE__, ret);
 216                 goto out;
 217         }
 218
 219         if (val & (1 << 4)) /* RTCA1 */
 220                 alrm->pending = 1;
 221
 222 out:
 223         mutex_unlock(&info->lock);
 224         return 0;
 225 }
 226
 227 static int max8997_rtc_stop_alarm(struct max8997_rtc_info *info)
 228 {
 229         u8 data[RTC_NR_TIME];
 230         int ret, i;
 231
 232         if (!mutex_is_locked(&info->lock))
 233                 dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
 234
 235         ret = max8997_bulk_read(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
 236                                 data);
 237         if (ret < 0) {
 238                 dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
 239                                 __func__, ret);
 240                 goto out;
 241         }
 242
 243         for (i = 0; i < RTC_NR_TIME; i++)
 244                 data[i] &= ~ALARM_ENABLE_MASK;
 245
 246         ret = max8997_bulk_write(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
 247                                  data);
 248         if (ret < 0) {
 249                 dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
 250                                 __func__, ret);
 251                 goto out;
 252         }
 253
 254         ret = max8997_rtc_set_update_reg(info);
 255 out:
 256         return ret;
 257 }
 258
 259 static int max8997_rtc_start_alarm(struct max8997_rtc_info *info)
 260 {
 261         u8 data[RTC_NR_TIME];
 262         int ret;
 263
 264         if (!mutex_is_locked(&info->lock))
 265                 dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
 266
 267         ret = max8997_bulk_read(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
 268                                 data);
 269         if (ret < 0) {
 270                 dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
 271                                 __func__, ret);
 272                 goto out;
 273         }
 274
 275         data[RTC_SEC] |= (1 << ALARM_ENABLE_SHIFT);
 276         data[RTC_MIN] |= (1 << ALARM_ENABLE_SHIFT);
 277         data[RTC_HOUR] |= (1 << ALARM_ENABLE_SHIFT);
 278         data[RTC_WEEKDAY] &= ~ALARM_ENABLE_MASK;
 279         if (data[RTC_MONTH] & 0xf)
 280                 data[RTC_MONTH] |= (1 << ALARM_ENABLE_SHIFT);
 281         if (data[RTC_YEAR] & 0x7f)
 282                 data[RTC_YEAR] |= (1 << ALARM_ENABLE_SHIFT);
 283         if (data[RTC_DATE] & 0x1f)
 284                 data[RTC_DATE] |= (1 << ALARM_ENABLE_SHIFT);
 285
 286         ret = max8997_bulk_write(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
 287                                  data);
 288         if (ret < 0) {
 289                 dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
 290                                 __func__, ret);
 291                 goto out;
 292         }
 293
 294         ret = max8997_rtc_set_update_reg(info);
 295 out:
 296         return ret;
 297 }
 298 static int max8997_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 299 {
 300         struct max8997_rtc_info *info = dev_get_drvdata(dev);
 301         u8 data[RTC_NR_TIME];
 302         int ret;
 303
 304         ret = max8997_rtc_tm_to_data(&alrm->time, data);
 305         if (ret < 0)
 306                 return ret;
 307
 308         dev_info(info->dev, "%s: %d-%02d-%02d %02d:%02d:%02d\n", __func__,
 309                         data[RTC_YEAR] + 2000, data[RTC_MONTH], data[RTC_DATE],
 310                         data[RTC_HOUR], data[RTC_MIN], data[RTC_SEC]);
 311
 312         mutex_lock(&info->lock);
 313
 314         ret = max8997_rtc_stop_alarm(info);
 315         if (ret < 0)
 316                 goto out;
 317
 318         ret = max8997_bulk_write(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
 319                                 data);
 320         if (ret < 0) {
 321                 dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
 322                                 __func__, ret);
 323                 goto out;
 324         }
 325
 326         ret = max8997_rtc_set_update_reg(info);
 327         if (ret < 0)
 328                 goto out;
 329
 330         if (alrm->enabled)
 331                 ret = max8997_rtc_start_alarm(info);
 332 out:
 333         mutex_unlock(&info->lock);
 334         return ret;
 335 }
 336
 337 static int max8997_rtc_alarm_irq_enable(struct device *dev,
 338                                         unsigned int enabled)
 339 {
 340         struct max8997_rtc_info *info = dev_get_drvdata(dev);
 341         int ret;
 342
 343         mutex_lock(&info->lock);
 344         if (enabled)
 345                 ret = max8997_rtc_start_alarm(info);
 346         else
 347                 ret = max8997_rtc_stop_alarm(info);
 348         mutex_unlock(&info->lock);
 349
 350         return ret;
 351 }
 352
 353 static irqreturn_t max8997_rtc_alarm_irq(int irq, void *data)
 354 {
 355         struct max8997_rtc_info *info = data;
 356
 357         dev_info(info->dev, "%s:irq(%d)\n", __func__, irq);
 358
 359         rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
 360
 361         return IRQ_HANDLED;
 362 }
 363
 364 static const struct rtc_class_ops max8997_rtc_ops = {
 365         .read_time = max8997_rtc_read_time,
 366         .set_time = max8997_rtc_set_time,
 367         .read_alarm = max8997_rtc_read_alarm,
 368         .set_alarm = max8997_rtc_set_alarm,
 369         .alarm_irq_enable = max8997_rtc_alarm_irq_enable,
 370 };
 371
 372 static void max8997_rtc_enable_wtsr(struct max8997_rtc_info *info, bool enable)
 373 {
 374         int ret;
 375         u8 val, mask;
 376
 377         if (!wtsr_en)
 378                 return;
 379
 380         if (enable)
 381                 val = (1 << WTSR_EN_SHIFT) | (3 << WTSRT_SHIFT);
 382         else
 383                 val = 0;
 384
 385         mask = WTSR_EN_MASK | WTSRT_MASK;
 386
 387         dev_info(info->dev, "%s: %s WTSR\n", __func__,
 388                         enable ? "enable" : "disable");
 389
 390         ret = max8997_update_reg(info->rtc, MAX8997_RTC_WTSR_SMPL, val, mask);
 391         if (ret < 0) {
 392                 dev_err(info->dev, "%s: fail to update WTSR reg(%d)\n",
 393                                 __func__, ret);
 394                 return;
 395         }
 396
 397         max8997_rtc_set_update_reg(info);
 398 }
 399
 400 static void max8997_rtc_enable_smpl(struct max8997_rtc_info *info, bool enable)
 401 {
 402         int ret;
 403         u8 val, mask;
 404
 405         if (!smpl_en)
 406                 return;
 407
 408         if (enable)
 409                 val = (1 << SMPL_EN_SHIFT) | (0 << SMPLT_SHIFT);
 410         else
 411                 val = 0;
 412
 413         mask = SMPL_EN_MASK | SMPLT_MASK;
 414
 415         dev_info(info->dev, "%s: %s SMPL\n", __func__,
 416                         enable ? "enable" : "disable");
 417
 418         ret = max8997_update_reg(info->rtc, MAX8997_RTC_WTSR_SMPL, val, mask);
 419         if (ret < 0) {
 420                 dev_err(info->dev, "%s: fail to update SMPL reg(%d)\n",
 421                                 __func__, ret);
 422                 return;
 423         }
 424
 425         max8997_rtc_set_update_reg(info);
 426
 427         val = 0;
 428         max8997_read_reg(info->rtc, MAX8997_RTC_WTSR_SMPL, &val);
 429         pr_info("WTSR_SMPL(0x%02x)\n", val);
 430 }
 431
 432 static int max8997_rtc_init_reg(struct max8997_rtc_info *info)
 433 {
 434         u8 data[2];
 435         int ret;
 436
 437         /* Set RTC control register : Binary mode, 24hour mdoe */
 438         data[0] = (1 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
 439         data[1] = (0 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
 440
 441         info->rtc_24hr_mode = 1;
 442
 443         ret = max8997_bulk_write(info->rtc, MAX8997_RTC_CTRLMASK, 2, data);
 444         if (ret < 0) {
 445                 dev_err(info->dev, "%s: fail to write controlm reg(%d)\n",
 446                                 __func__, ret);
 447                 return ret;
 448         }
 449
 450         ret = max8997_rtc_set_update_reg(info);
 451         return ret;
 452 }
 453
 454 static int max8997_rtc_probe(struct platform_device *pdev)
 455 {
 456         struct max8997_dev *max8997 = dev_get_drvdata(pdev->dev.parent);
 457         struct max8997_rtc_info *info;
 458         int ret, virq;
 459
 460         info = devm_kzalloc(&pdev->dev, sizeof(struct max8997_rtc_info),
 461                         GFP_KERNEL);
 462         if (!info)
 463                 return -ENOMEM;
 464
 465         mutex_init(&info->lock);
 466         info->dev = &pdev->dev;
 467         info->max8997 = max8997;
 468         info->rtc = max8997->rtc;
 469
 470         platform_set_drvdata(pdev, info);
 471
 472         ret = max8997_rtc_init_reg(info);
 473
 474         if (ret < 0) {
 475                 dev_err(&pdev->dev, "Failed to initialize RTC reg:%d\n", ret);
 476                 return ret;
 477         }
 478
 479         max8997_rtc_enable_wtsr(info, true);
 480         max8997_rtc_enable_smpl(info, true);
 481
 482         device_init_wakeup(&pdev->dev, 1);
 483
 484         info->rtc_dev = devm_rtc_device_register(&pdev->dev, "max8997-rtc",
 485                                         &max8997_rtc_ops, THIS_MODULE);
 486
 487         if (IS_ERR(info->rtc_dev)) {
 488                 ret = PTR_ERR(info->rtc_dev);
 489                 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
 490                 return ret;
 491         }
 492
 493         virq = irq_create_mapping(max8997->irq_domain, MAX8997_PMICIRQ_RTCA1);
 494         if (!virq) {
 495                 dev_err(&pdev->dev, "Failed to create mapping alarm IRQ\n");
 496                 ret = -ENXIO;
 497                 goto err_out;
 498         }
 499         info->virq = virq;
 500
 501         ret = devm_request_threaded_irq(&pdev->dev, virq, NULL,
 502                                 max8997_rtc_alarm_irq, 0,
 503                                 "rtc-alarm0", info);
 504         if (ret < 0)
 505                 dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
 506                         info->virq, ret);
 507
 508 err_out:
 509         return ret;
 510 }
 511
 512 static void max8997_rtc_shutdown(struct platform_device *pdev)
 513 {
 514         struct max8997_rtc_info *info = platform_get_drvdata(pdev);
 515
 516         max8997_rtc_enable_wtsr(info, false);
 517         max8997_rtc_enable_smpl(info, false);
 518 }
 519
 520 static const struct platform_device_id rtc_id[] = {
 521         { "max8997-rtc", 0 },
 522         {},
 523 };
 524
 525 static struct platform_driver max8997_rtc_driver = {
 526         .driver         = {
 527                 .name   = "max8997-rtc",
 528         },
 529         .probe          = max8997_rtc_probe,
 530         .shutdown       = max8997_rtc_shutdown,
 531         .id_table       = rtc_id,
 532 };
 533
 534 module_platform_driver(max8997_rtc_driver);
 535
 536 MODULE_DESCRIPTION("Maxim MAX8997 RTC driver");
 537 MODULE_AUTHOR("<ms925.kim@samsung.com>");
 538 MODULE_LICENSE("GPL");