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