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 #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/max77686-private.h>
  24 #include <linux/irqdomain.h>
  25 #include <linux/regmap.h>
  26
  27 /* RTC Control Register */
  28 #define BCD_EN_SHIFT                    0
  29 #define BCD_EN_MASK                     (1 << BCD_EN_SHIFT)
  30 #define MODEL24_SHIFT                   1
  31 #define MODEL24_MASK                    (1 << MODEL24_SHIFT)
  32 /* RTC Update Register1 */
  33 #define RTC_UDR_SHIFT                   0
  34 #define RTC_UDR_MASK                    (1 << RTC_UDR_SHIFT)
  35 #define RTC_RBUDR_SHIFT                 4
  36 #define RTC_RBUDR_MASK                  (1 << RTC_RBUDR_SHIFT)
  37 /* RTC Hour register */
  38 #define HOUR_PM_SHIFT                   6
  39 #define HOUR_PM_MASK                    (1 << HOUR_PM_SHIFT)
  40 /* RTC Alarm Enable */
  41 #define ALARM_ENABLE_SHIFT              7
  42 #define ALARM_ENABLE_MASK               (1 << ALARM_ENABLE_SHIFT)
  43
  44 #define MAX77686_RTC_UPDATE_DELAY       16
  45
  46 enum {
  47         RTC_SEC = 0,
  48         RTC_MIN,
  49         RTC_HOUR,
  50         RTC_WEEKDAY,
  51         RTC_MONTH,
  52         RTC_YEAR,
  53         RTC_DATE,
  54         RTC_NR_TIME
  55 };
  56
  57 struct max77686_rtc_info {
  58         struct device           *dev;
  59         struct max77686_dev     *max77686;
  60         struct i2c_client       *rtc;
  61         struct rtc_device       *rtc_dev;
  62         struct mutex            lock;
  63
  64         struct regmap           *regmap;
  65
  66         int virq;
  67         int rtc_24hr_mode;
  68 };
  69
  70 enum MAX77686_RTC_OP {
  71         MAX77686_RTC_WRITE,
  72         MAX77686_RTC_READ,
  73 };
  74
  75 static void max77686_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
  76                                    int rtc_24hr_mode)
  77 {
  78         tm->tm_sec = data[RTC_SEC] & 0x7f;
  79         tm->tm_min = data[RTC_MIN] & 0x7f;
  80         if (rtc_24hr_mode)
  81                 tm->tm_hour = data[RTC_HOUR] & 0x1f;
  82         else {
  83                 tm->tm_hour = data[RTC_HOUR] & 0x0f;
  84                 if (data[RTC_HOUR] & HOUR_PM_MASK)
  85                         tm->tm_hour += 12;
  86         }
  87
  88         /* Only a single bit is set in data[], so fls() would be equivalent */
  89         tm->tm_wday = ffs(data[RTC_WEEKDAY] & 0x7f) - 1;
  90         tm->tm_mday = data[RTC_DATE] & 0x1f;
  91         tm->tm_mon = (data[RTC_MONTH] & 0x0f) - 1;
  92         tm->tm_year = (data[RTC_YEAR] & 0x7f) + 100;
  93         tm->tm_yday = 0;
  94         tm->tm_isdst = 0;
  95 }
  96
  97 static int max77686_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
  98 {
  99         data[RTC_SEC] = tm->tm_sec;
 100         data[RTC_MIN] = tm->tm_min;
 101         data[RTC_HOUR] = tm->tm_hour;
 102         data[RTC_WEEKDAY] = 1 << tm->tm_wday;
 103         data[RTC_DATE] = tm->tm_mday;
 104         data[RTC_MONTH] = tm->tm_mon + 1;
 105         data[RTC_YEAR] = tm->tm_year > 100 ? (tm->tm_year - 100) : 0;
 106
 107         if (tm->tm_year < 100) {
 108                 pr_warn("RTC cannot handle the year %d.  Assume it's 2000.\n",
 109                         1900 + tm->tm_year);
 110                 return -EINVAL;
 111         }
 112         return 0;
 113 }
 114
 115 static int max77686_rtc_update(struct max77686_rtc_info *info,
 116         enum MAX77686_RTC_OP op)
 117 {
 118         int ret;
 119         unsigned int data;
 120
 121         if (op == MAX77686_RTC_WRITE)
 122                 data = 1 << RTC_UDR_SHIFT;
 123         else
 124                 data = 1 << RTC_RBUDR_SHIFT;
 125
 126         ret = regmap_update_bits(info->max77686->rtc_regmap,
 127                                  MAX77686_RTC_UPDATE0, data, data);
 128         if (ret < 0)
 129                 dev_err(info->dev, "%s: fail to write update reg(ret=%d, data=0x%x)\n",
 130                                 __func__, ret, data);
 131         else {
 132                 /* Minimum 16ms delay required before RTC update. */
 133                 msleep(MAX77686_RTC_UPDATE_DELAY);
 134         }
 135
 136         return ret;
 137 }
 138
 139 static int max77686_rtc_read_time(struct device *dev, struct rtc_time *tm)
 140 {
 141         struct max77686_rtc_info *info = dev_get_drvdata(dev);
 142         u8 data[RTC_NR_TIME];
 143         int ret;
 144
 145         mutex_lock(&info->lock);
 146
 147         ret = max77686_rtc_update(info, MAX77686_RTC_READ);
 148         if (ret < 0)
 149                 goto out;
 150
 151         ret = regmap_bulk_read(info->max77686->rtc_regmap,
 152                                 MAX77686_RTC_SEC, data, RTC_NR_TIME);
 153         if (ret < 0) {
 154                 dev_err(info->dev, "%s: fail to read time reg(%d)\n", __func__, ret);
 155                 goto out;
 156         }
 157
 158         max77686_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);
 159
 160         ret = rtc_valid_tm(tm);
 161
 162 out:
 163         mutex_unlock(&info->lock);
 164         return ret;
 165 }
 166
 167 static int max77686_rtc_set_time(struct device *dev, struct rtc_time *tm)
 168 {
 169         struct max77686_rtc_info *info = dev_get_drvdata(dev);
 170         u8 data[RTC_NR_TIME];
 171         int ret;
 172
 173         ret = max77686_rtc_tm_to_data(tm, data);
 174         if (ret < 0)
 175                 return ret;
 176
 177         mutex_lock(&info->lock);
 178
 179         ret = regmap_bulk_write(info->max77686->rtc_regmap,
 180                                  MAX77686_RTC_SEC, data, RTC_NR_TIME);
 181         if (ret < 0) {
 182                 dev_err(info->dev, "%s: fail to write time reg(%d)\n", __func__,
 183                                 ret);
 184                 goto out;
 185         }
 186
 187         ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
 188
 189 out:
 190         mutex_unlock(&info->lock);
 191         return ret;
 192 }
 193
 194 static int max77686_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 195 {
 196         struct max77686_rtc_info *info = dev_get_drvdata(dev);
 197         u8 data[RTC_NR_TIME];
 198         unsigned int val;
 199         int i, ret;
 200
 201         mutex_lock(&info->lock);
 202
 203         ret = max77686_rtc_update(info, MAX77686_RTC_READ);
 204         if (ret < 0)
 205                 goto out;
 206
 207         ret = regmap_bulk_read(info->max77686->rtc_regmap,
 208                                  MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
 209         if (ret < 0) {
 210                 dev_err(info->dev, "%s:%d fail to read alarm reg(%d)\n",
 211                                 __func__, __LINE__, ret);
 212                 goto out;
 213         }
 214
 215         max77686_rtc_data_to_tm(data, &alrm->time, info->rtc_24hr_mode);
 216
 217         alrm->enabled = 0;
 218         for (i = 0; i < RTC_NR_TIME; i++) {
 219                 if (data[i] & ALARM_ENABLE_MASK) {
 220                         alrm->enabled = 1;
 221                         break;
 222                 }
 223         }
 224
 225         alrm->pending = 0;
 226         ret = regmap_read(info->max77686->regmap, MAX77686_REG_STATUS2, &val);
 227         if (ret < 0) {
 228                 dev_err(info->dev, "%s:%d fail to read status2 reg(%d)\n",
 229                                 __func__, __LINE__, ret);
 230                 goto out;
 231         }
 232
 233         if (val & (1 << 4)) /* RTCA1 */
 234                 alrm->pending = 1;
 235
 236 out:
 237         mutex_unlock(&info->lock);
 238         return 0;
 239 }
 240
 241 static int max77686_rtc_stop_alarm(struct max77686_rtc_info *info)
 242 {
 243         u8 data[RTC_NR_TIME];
 244         int ret, i;
 245         struct rtc_time tm;
 246
 247         if (!mutex_is_locked(&info->lock))
 248                 dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
 249
 250         ret = max77686_rtc_update(info, MAX77686_RTC_READ);
 251         if (ret < 0)
 252                 goto out;
 253
 254         ret = regmap_bulk_read(info->max77686->rtc_regmap,
 255                                  MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
 256         if (ret < 0) {
 257                 dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
 258                                 __func__, ret);
 259                 goto out;
 260         }
 261
 262         max77686_rtc_data_to_tm(data, &tm, info->rtc_24hr_mode);
 263
 264         for (i = 0; i < RTC_NR_TIME; i++)
 265                 data[i] &= ~ALARM_ENABLE_MASK;
 266
 267         ret = regmap_bulk_write(info->max77686->rtc_regmap,
 268                                  MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
 269         if (ret < 0) {
 270                 dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
 271                                 __func__, ret);
 272                 goto out;
 273         }
 274
 275         ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
 276 out:
 277         return ret;
 278 }
 279
 280 static int max77686_rtc_start_alarm(struct max77686_rtc_info *info)
 281 {
 282         u8 data[RTC_NR_TIME];
 283         int ret;
 284         struct rtc_time tm;
 285
 286         if (!mutex_is_locked(&info->lock))
 287                 dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
 288
 289         ret = max77686_rtc_update(info, MAX77686_RTC_READ);
 290         if (ret < 0)
 291                 goto out;
 292
 293         ret = regmap_bulk_read(info->max77686->rtc_regmap,
 294                                  MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
 295         if (ret < 0) {
 296                 dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
 297                                 __func__, ret);
 298                 goto out;
 299         }
 300
 301         max77686_rtc_data_to_tm(data, &tm, info->rtc_24hr_mode);
 302
 303         data[RTC_SEC] |= (1 << ALARM_ENABLE_SHIFT);
 304         data[RTC_MIN] |= (1 << ALARM_ENABLE_SHIFT);
 305         data[RTC_HOUR] |= (1 << ALARM_ENABLE_SHIFT);
 306         data[RTC_WEEKDAY] &= ~ALARM_ENABLE_MASK;
 307         if (data[RTC_MONTH] & 0xf)
 308                 data[RTC_MONTH] |= (1 << ALARM_ENABLE_SHIFT);
 309         if (data[RTC_YEAR] & 0x7f)
 310                 data[RTC_YEAR] |= (1 << ALARM_ENABLE_SHIFT);
 311         if (data[RTC_DATE] & 0x1f)
 312                 data[RTC_DATE] |= (1 << ALARM_ENABLE_SHIFT);
 313
 314         ret = regmap_bulk_write(info->max77686->rtc_regmap,
 315                                  MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
 316         if (ret < 0) {
 317                 dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
 318                                 __func__, ret);
 319                 goto out;
 320         }
 321
 322         ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
 323 out:
 324         return ret;
 325 }
 326
 327 static int max77686_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 328 {
 329         struct max77686_rtc_info *info = dev_get_drvdata(dev);
 330         u8 data[RTC_NR_TIME];
 331         int ret;
 332
 333         ret = max77686_rtc_tm_to_data(&alrm->time, data);
 334         if (ret < 0)
 335                 return ret;
 336
 337         mutex_lock(&info->lock);
 338
 339         ret = max77686_rtc_stop_alarm(info);
 340         if (ret < 0)
 341                 goto out;
 342
 343         ret = regmap_bulk_write(info->max77686->rtc_regmap,
 344                                  MAX77686_ALARM1_SEC, data, RTC_NR_TIME);
 345
 346         if (ret < 0) {
 347                 dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
 348                                 __func__, ret);
 349                 goto out;
 350         }
 351
 352         ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
 353         if (ret < 0)
 354                 goto out;
 355
 356         if (alrm->enabled)
 357                 ret = max77686_rtc_start_alarm(info);
 358 out:
 359         mutex_unlock(&info->lock);
 360         return ret;
 361 }
 362
 363 static int max77686_rtc_alarm_irq_enable(struct device *dev,
 364                                         unsigned int enabled)
 365 {
 366         struct max77686_rtc_info *info = dev_get_drvdata(dev);
 367         int ret;
 368
 369         mutex_lock(&info->lock);
 370         if (enabled)
 371                 ret = max77686_rtc_start_alarm(info);
 372         else
 373                 ret = max77686_rtc_stop_alarm(info);
 374         mutex_unlock(&info->lock);
 375
 376         return ret;
 377 }
 378
 379 static irqreturn_t max77686_rtc_alarm_irq(int irq, void *data)
 380 {
 381         struct max77686_rtc_info *info = data;
 382
 383         dev_info(info->dev, "%s:irq(%d)\n", __func__, irq);
 384
 385         rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
 386
 387         return IRQ_HANDLED;
 388 }
 389
 390 static const struct rtc_class_ops max77686_rtc_ops = {
 391         .read_time = max77686_rtc_read_time,
 392         .set_time = max77686_rtc_set_time,
 393         .read_alarm = max77686_rtc_read_alarm,
 394         .set_alarm = max77686_rtc_set_alarm,
 395         .alarm_irq_enable = max77686_rtc_alarm_irq_enable,
 396 };
 397
 398 static int max77686_rtc_init_reg(struct max77686_rtc_info *info)
 399 {
 400         u8 data[2];
 401         int ret;
 402
 403         /* Set RTC control register : Binary mode, 24hour mdoe */
 404         data[0] = (1 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
 405         data[1] = (0 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
 406
 407         info->rtc_24hr_mode = 1;
 408
 409         ret = regmap_bulk_write(info->max77686->rtc_regmap, MAX77686_RTC_CONTROLM, data, 2);
 410         if (ret < 0) {
 411                 dev_err(info->dev, "%s: fail to write controlm reg(%d)\n",
 412                                 __func__, ret);
 413                 return ret;
 414         }
 415
 416         ret = max77686_rtc_update(info, MAX77686_RTC_WRITE);
 417         return ret;
 418 }
 419
 420 static int max77686_rtc_probe(struct platform_device *pdev)
 421 {
 422         struct max77686_dev *max77686 = dev_get_drvdata(pdev->dev.parent);
 423         struct max77686_rtc_info *info;
 424         int ret;
 425
 426         dev_info(&pdev->dev, "%s\n", __func__);
 427
 428         info = devm_kzalloc(&pdev->dev, sizeof(struct max77686_rtc_info),
 429                                 GFP_KERNEL);
 430         if (!info)
 431                 return -ENOMEM;
 432
 433         mutex_init(&info->lock);
 434         info->dev = &pdev->dev;
 435         info->max77686 = max77686;
 436         info->rtc = max77686->rtc;
 437
 438         platform_set_drvdata(pdev, info);
 439
 440         ret = max77686_rtc_init_reg(info);
 441
 442         if (ret < 0) {
 443                 dev_err(&pdev->dev, "Failed to initialize RTC reg:%d\n", ret);
 444                 goto err_rtc;
 445         }
 446
 447         device_init_wakeup(&pdev->dev, 1);
 448
 449         info->rtc_dev = devm_rtc_device_register(&pdev->dev, "max77686-rtc",
 450                                         &max77686_rtc_ops, THIS_MODULE);
 451
 452         if (IS_ERR(info->rtc_dev)) {
 453                 ret = PTR_ERR(info->rtc_dev);
 454                 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
 455                 if (ret == 0)
 456                         ret = -EINVAL;
 457                 goto err_rtc;
 458         }
 459
 460         if (!max77686->rtc_irq_data) {
 461                 ret = -EINVAL;
 462                 dev_err(&pdev->dev, "%s: no RTC regmap IRQ chip\n", __func__);
 463                 goto err_rtc;
 464         }
 465
 466         info->virq = regmap_irq_get_virq(max77686->rtc_irq_data,
 467                                          MAX77686_RTCIRQ_RTCA1);
 468         if (!info->virq) {
 469                 ret = -ENXIO;
 470                 goto err_rtc;
 471         }
 472
 473         ret = devm_request_threaded_irq(&pdev->dev, info->virq, NULL,
 474                                 max77686_rtc_alarm_irq, 0, "rtc-alarm1", info);
 475         if (ret < 0)
 476                 dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
 477                         info->virq, ret);
 478
 479 err_rtc:
 480         return ret;
 481 }
 482
 483 #ifdef CONFIG_PM_SLEEP
 484 static int max77686_rtc_suspend(struct device *dev)
 485 {
 486         if (device_may_wakeup(dev)) {
 487                 struct max77686_rtc_info *info = dev_get_drvdata(dev);
 488
 489                 return enable_irq_wake(info->virq);
 490         }
 491
 492         return 0;
 493 }
 494
 495 static int max77686_rtc_resume(struct device *dev)
 496 {
 497         if (device_may_wakeup(dev)) {
 498                 struct max77686_rtc_info *info = dev_get_drvdata(dev);
 499
 500                 return disable_irq_wake(info->virq);
 501         }
 502
 503         return 0;
 504 }
 505 #endif
 506
 507 static SIMPLE_DEV_PM_OPS(max77686_rtc_pm_ops,
 508                          max77686_rtc_suspend, max77686_rtc_resume);
 509
 510 static const struct platform_device_id rtc_id[] = {
 511         { "max77686-rtc", 0 },
 512         {},
 513 };
 514 MODULE_DEVICE_TABLE(platform, rtc_id);
 515
 516 static struct platform_driver max77686_rtc_driver = {
 517         .driver         = {
 518                 .name   = "max77686-rtc",
 519                 .pm     = &max77686_rtc_pm_ops,
 520         },
 521         .probe          = max77686_rtc_probe,
 522         .id_table       = rtc_id,
 523 };
 524
 525 module_platform_driver(max77686_rtc_driver);
 526
 527 MODULE_DESCRIPTION("Maxim MAX77686 RTC driver");
 528 MODULE_AUTHOR("Chiwoong Byun <woong.byun@samsung.com>");
 529 MODULE_LICENSE("GPL");