linux/drivers/rtc/rtc-max8997.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2//
   3// RTC driver for Maxim MAX8997
   4//
   5// Copyright (C) 2013 Samsung Electronics Co.Ltd
   6//
   7//  based on rtc-max8998.c
   8
   9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11#include <linux/slab.h>
  12#include <linux/rtc.h>
  13#include <linux/delay.h>
  14#include <linux/mutex.h>
  15#include <linux/module.h>
  16#include <linux/platform_device.h>
  17#include <linux/mfd/max8997-private.h>
  18#include <linux/irqdomain.h>
  19
  20/* Module parameter for WTSR function control */
  21static int wtsr_en = 1;
  22module_param(wtsr_en, int, 0444);
  23MODULE_PARM_DESC(wtsr_en, "Watchdog Timeout & Software Reset (default=on)");
  24/* Module parameter for SMPL function control */
  25static int smpl_en = 1;
  26module_param(smpl_en, int, 0444);
  27MODULE_PARM_DESC(smpl_en, "Sudden Momentary Power Loss (default=on)");
  28
  29/* RTC Control Register */
  30#define BCD_EN_SHIFT                    0
  31#define BCD_EN_MASK                     (1 << BCD_EN_SHIFT)
  32#define MODEL24_SHIFT                   1
  33#define MODEL24_MASK                    (1 << MODEL24_SHIFT)
  34/* RTC Update Register1 */
  35#define RTC_UDR_SHIFT                   0
  36#define RTC_UDR_MASK                    (1 << RTC_UDR_SHIFT)
  37/* WTSR and SMPL Register */
  38#define WTSRT_SHIFT                     0
  39#define SMPLT_SHIFT                     2
  40#define WTSR_EN_SHIFT                   6
  41#define SMPL_EN_SHIFT                   7
  42#define WTSRT_MASK                      (3 << WTSRT_SHIFT)
  43#define SMPLT_MASK                      (3 << SMPLT_SHIFT)
  44#define WTSR_EN_MASK                    (1 << WTSR_EN_SHIFT)
  45#define SMPL_EN_MASK                    (1 << SMPL_EN_SHIFT)
  46/* RTC Hour register */
  47#define HOUR_PM_SHIFT                   6
  48#define HOUR_PM_MASK                    (1 << HOUR_PM_SHIFT)
  49/* RTC Alarm Enable */
  50#define ALARM_ENABLE_SHIFT              7
  51#define ALARM_ENABLE_MASK               (1 << ALARM_ENABLE_SHIFT)
  52
  53enum {
  54        RTC_SEC = 0,
  55        RTC_MIN,
  56        RTC_HOUR,
  57        RTC_WEEKDAY,
  58        RTC_MONTH,
  59        RTC_YEAR,
  60        RTC_DATE,
  61        RTC_NR_TIME
  62};
  63
  64struct max8997_rtc_info {
  65        struct device           *dev;
  66        struct max8997_dev      *max8997;
  67        struct i2c_client       *rtc;
  68        struct rtc_device       *rtc_dev;
  69        struct mutex            lock;
  70        int virq;
  71        int rtc_24hr_mode;
  72};
  73
  74static void max8997_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
  75                                   int rtc_24hr_mode)
  76{
  77        tm->tm_sec = data[RTC_SEC] & 0x7f;
  78        tm->tm_min = data[RTC_MIN] & 0x7f;
  79        if (rtc_24hr_mode)
  80                tm->tm_hour = data[RTC_HOUR] & 0x1f;
  81        else {
  82                tm->tm_hour = data[RTC_HOUR] & 0x0f;
  83                if (data[RTC_HOUR] & HOUR_PM_MASK)
  84                        tm->tm_hour += 12;
  85        }
  86
  87        tm->tm_wday = fls(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
  95static int max8997_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("RTC cannot handle the year %d.  Assume it's 2000.\n",
 107                        1900 + tm->tm_year);
 108                return -EINVAL;
 109        }
 110        return 0;
 111}
 112
 113static inline int max8997_rtc_set_update_reg(struct max8997_rtc_info *info)
 114{
 115        int ret;
 116
 117        ret = max8997_write_reg(info->rtc, MAX8997_RTC_UPDATE1,
 118                                                RTC_UDR_MASK);
 119        if (ret < 0)
 120                dev_err(info->dev, "%s: fail to write update reg(%d)\n",
 121                                __func__, ret);
 122        else {
 123                /* Minimum 16ms delay required before RTC update.
 124                 * Otherwise, we may read and update based on out-of-date
 125                 * value */
 126                msleep(20);
 127        }
 128
 129        return ret;
 130}
 131
 132static int max8997_rtc_read_time(struct device *dev, struct rtc_time *tm)
 133{
 134        struct max8997_rtc_info *info = dev_get_drvdata(dev);
 135        u8 data[RTC_NR_TIME];
 136        int ret;
 137
 138        mutex_lock(&info->lock);
 139        ret = max8997_bulk_read(info->rtc, MAX8997_RTC_SEC, RTC_NR_TIME, data);
 140        mutex_unlock(&info->lock);
 141
 142        if (ret < 0) {
 143                dev_err(info->dev, "%s: fail to read time reg(%d)\n", __func__,
 144                                ret);
 145                return ret;
 146        }
 147
 148        max8997_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);
 149
 150        return 0;
 151}
 152
 153static int max8997_rtc_set_time(struct device *dev, struct rtc_time *tm)
 154{
 155        struct max8997_rtc_info *info = dev_get_drvdata(dev);
 156        u8 data[RTC_NR_TIME];
 157        int ret;
 158
 159        ret = max8997_rtc_tm_to_data(tm, data);
 160        if (ret < 0)
 161                return ret;
 162
 163        mutex_lock(&info->lock);
 164
 165        ret = max8997_bulk_write(info->rtc, MAX8997_RTC_SEC, RTC_NR_TIME, data);
 166        if (ret < 0) {
 167                dev_err(info->dev, "%s: fail to write time reg(%d)\n", __func__,
 168                                ret);
 169                goto out;
 170        }
 171
 172        ret = max8997_rtc_set_update_reg(info);
 173out:
 174        mutex_unlock(&info->lock);
 175        return ret;
 176}
 177
 178static int max8997_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 179{
 180        struct max8997_rtc_info *info = dev_get_drvdata(dev);
 181        u8 data[RTC_NR_TIME];
 182        u8 val;
 183        int i, ret;
 184
 185        mutex_lock(&info->lock);
 186
 187        ret = max8997_bulk_read(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
 188                        data);
 189        if (ret < 0) {
 190                dev_err(info->dev, "%s:%d fail to read alarm reg(%d)\n",
 191                                __func__, __LINE__, ret);
 192                goto out;
 193        }
 194
 195        max8997_rtc_data_to_tm(data, &alrm->time, info->rtc_24hr_mode);
 196
 197        alrm->enabled = 0;
 198        for (i = 0; i < RTC_NR_TIME; i++) {
 199                if (data[i] & ALARM_ENABLE_MASK) {
 200                        alrm->enabled = 1;
 201                        break;
 202                }
 203        }
 204
 205        alrm->pending = 0;
 206        ret = max8997_read_reg(info->max8997->i2c, MAX8997_REG_STATUS1, &val);
 207        if (ret < 0) {
 208                dev_err(info->dev, "%s:%d fail to read status1 reg(%d)\n",
 209                                __func__, __LINE__, ret);
 210                goto out;
 211        }
 212
 213        if (val & (1 << 4)) /* RTCA1 */
 214                alrm->pending = 1;
 215
 216out:
 217        mutex_unlock(&info->lock);
 218        return ret;
 219}
 220
 221static int max8997_rtc_stop_alarm(struct max8997_rtc_info *info)
 222{
 223        u8 data[RTC_NR_TIME];
 224        int ret, i;
 225
 226        if (!mutex_is_locked(&info->lock))
 227                dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
 228
 229        ret = max8997_bulk_read(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
 230                                data);
 231        if (ret < 0) {
 232                dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
 233                                __func__, ret);
 234                goto out;
 235        }
 236
 237        for (i = 0; i < RTC_NR_TIME; i++)
 238                data[i] &= ~ALARM_ENABLE_MASK;
 239
 240        ret = max8997_bulk_write(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
 241                                 data);
 242        if (ret < 0) {
 243                dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
 244                                __func__, ret);
 245                goto out;
 246        }
 247
 248        ret = max8997_rtc_set_update_reg(info);
 249out:
 250        return ret;
 251}
 252
 253static int max8997_rtc_start_alarm(struct max8997_rtc_info *info)
 254{
 255        u8 data[RTC_NR_TIME];
 256        int ret;
 257
 258        if (!mutex_is_locked(&info->lock))
 259                dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
 260
 261        ret = max8997_bulk_read(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
 262                                data);
 263        if (ret < 0) {
 264                dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
 265                                __func__, ret);
 266                goto out;
 267        }
 268
 269        data[RTC_SEC] |= (1 << ALARM_ENABLE_SHIFT);
 270        data[RTC_MIN] |= (1 << ALARM_ENABLE_SHIFT);
 271        data[RTC_HOUR] |= (1 << ALARM_ENABLE_SHIFT);
 272        data[RTC_WEEKDAY] &= ~ALARM_ENABLE_MASK;
 273        if (data[RTC_MONTH] & 0xf)
 274                data[RTC_MONTH] |= (1 << ALARM_ENABLE_SHIFT);
 275        if (data[RTC_YEAR] & 0x7f)
 276                data[RTC_YEAR] |= (1 << ALARM_ENABLE_SHIFT);
 277        if (data[RTC_DATE] & 0x1f)
 278                data[RTC_DATE] |= (1 << ALARM_ENABLE_SHIFT);
 279
 280        ret = max8997_bulk_write(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
 281                                 data);
 282        if (ret < 0) {
 283                dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
 284                                __func__, ret);
 285                goto out;
 286        }
 287
 288        ret = max8997_rtc_set_update_reg(info);
 289out:
 290        return ret;
 291}
 292static int max8997_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 293{
 294        struct max8997_rtc_info *info = dev_get_drvdata(dev);
 295        u8 data[RTC_NR_TIME];
 296        int ret;
 297
 298        ret = max8997_rtc_tm_to_data(&alrm->time, data);
 299        if (ret < 0)
 300                return ret;
 301
 302        dev_info(info->dev, "%s: %d-%02d-%02d %02d:%02d:%02d\n", __func__,
 303                        data[RTC_YEAR] + 2000, data[RTC_MONTH], data[RTC_DATE],
 304                        data[RTC_HOUR], data[RTC_MIN], data[RTC_SEC]);
 305
 306        mutex_lock(&info->lock);
 307
 308        ret = max8997_rtc_stop_alarm(info);
 309        if (ret < 0)
 310                goto out;
 311
 312        ret = max8997_bulk_write(info->rtc, MAX8997_RTC_ALARM1_SEC, RTC_NR_TIME,
 313                                data);
 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 = max8997_rtc_set_update_reg(info);
 321        if (ret < 0)
 322                goto out;
 323
 324        if (alrm->enabled)
 325                ret = max8997_rtc_start_alarm(info);
 326out:
 327        mutex_unlock(&info->lock);
 328        return ret;
 329}
 330
 331static int max8997_rtc_alarm_irq_enable(struct device *dev,
 332                                        unsigned int enabled)
 333{
 334        struct max8997_rtc_info *info = dev_get_drvdata(dev);
 335        int ret;
 336
 337        mutex_lock(&info->lock);
 338        if (enabled)
 339                ret = max8997_rtc_start_alarm(info);
 340        else
 341                ret = max8997_rtc_stop_alarm(info);
 342        mutex_unlock(&info->lock);
 343
 344        return ret;
 345}
 346
 347static irqreturn_t max8997_rtc_alarm_irq(int irq, void *data)
 348{
 349        struct max8997_rtc_info *info = data;
 350
 351        dev_info(info->dev, "%s:irq(%d)\n", __func__, irq);
 352
 353        rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
 354
 355        return IRQ_HANDLED;
 356}
 357
 358static const struct rtc_class_ops max8997_rtc_ops = {
 359        .read_time = max8997_rtc_read_time,
 360        .set_time = max8997_rtc_set_time,
 361        .read_alarm = max8997_rtc_read_alarm,
 362        .set_alarm = max8997_rtc_set_alarm,
 363        .alarm_irq_enable = max8997_rtc_alarm_irq_enable,
 364};
 365
 366static void max8997_rtc_enable_wtsr(struct max8997_rtc_info *info, bool enable)
 367{
 368        int ret;
 369        u8 val, mask;
 370
 371        if (!wtsr_en)
 372                return;
 373
 374        if (enable)
 375                val = (1 << WTSR_EN_SHIFT) | (3 << WTSRT_SHIFT);
 376        else
 377                val = 0;
 378
 379        mask = WTSR_EN_MASK | WTSRT_MASK;
 380
 381        dev_info(info->dev, "%s: %s WTSR\n", __func__,
 382                        enable ? "enable" : "disable");
 383
 384        ret = max8997_update_reg(info->rtc, MAX8997_RTC_WTSR_SMPL, val, mask);
 385        if (ret < 0) {
 386                dev_err(info->dev, "%s: fail to update WTSR reg(%d)\n",
 387                                __func__, ret);
 388                return;
 389        }
 390
 391        max8997_rtc_set_update_reg(info);
 392}
 393
 394static void max8997_rtc_enable_smpl(struct max8997_rtc_info *info, bool enable)
 395{
 396        int ret;
 397        u8 val, mask;
 398
 399        if (!smpl_en)
 400                return;
 401
 402        if (enable)
 403                val = (1 << SMPL_EN_SHIFT) | (0 << SMPLT_SHIFT);
 404        else
 405                val = 0;
 406
 407        mask = SMPL_EN_MASK | SMPLT_MASK;
 408
 409        dev_info(info->dev, "%s: %s SMPL\n", __func__,
 410                        enable ? "enable" : "disable");
 411
 412        ret = max8997_update_reg(info->rtc, MAX8997_RTC_WTSR_SMPL, val, mask);
 413        if (ret < 0) {
 414                dev_err(info->dev, "%s: fail to update SMPL reg(%d)\n",
 415                                __func__, ret);
 416                return;
 417        }
 418
 419        max8997_rtc_set_update_reg(info);
 420
 421        val = 0;
 422        max8997_read_reg(info->rtc, MAX8997_RTC_WTSR_SMPL, &val);
 423        pr_info("WTSR_SMPL(0x%02x)\n", val);
 424}
 425
 426static int max8997_rtc_init_reg(struct max8997_rtc_info *info)
 427{
 428        u8 data[2];
 429        int ret;
 430
 431        /* Set RTC control register : Binary mode, 24hour mdoe */
 432        data[0] = (1 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
 433        data[1] = (0 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
 434
 435        info->rtc_24hr_mode = 1;
 436
 437        ret = max8997_bulk_write(info->rtc, MAX8997_RTC_CTRLMASK, 2, data);
 438        if (ret < 0) {
 439                dev_err(info->dev, "%s: fail to write controlm reg(%d)\n",
 440                                __func__, ret);
 441                return ret;
 442        }
 443
 444        ret = max8997_rtc_set_update_reg(info);
 445        return ret;
 446}
 447
 448static int max8997_rtc_probe(struct platform_device *pdev)
 449{
 450        struct max8997_dev *max8997 = dev_get_drvdata(pdev->dev.parent);
 451        struct max8997_rtc_info *info;
 452        int ret, virq;
 453
 454        info = devm_kzalloc(&pdev->dev, sizeof(struct max8997_rtc_info),
 455                        GFP_KERNEL);
 456        if (!info)
 457                return -ENOMEM;
 458
 459        mutex_init(&info->lock);
 460        info->dev = &pdev->dev;
 461        info->max8997 = max8997;
 462        info->rtc = max8997->rtc;
 463
 464        platform_set_drvdata(pdev, info);
 465
 466        ret = max8997_rtc_init_reg(info);
 467
 468        if (ret < 0) {
 469                dev_err(&pdev->dev, "Failed to initialize RTC reg:%d\n", ret);
 470                return ret;
 471        }
 472
 473        max8997_rtc_enable_wtsr(info, true);
 474        max8997_rtc_enable_smpl(info, true);
 475
 476        device_init_wakeup(&pdev->dev, 1);
 477
 478        info->rtc_dev = devm_rtc_device_register(&pdev->dev, "max8997-rtc",
 479                                        &max8997_rtc_ops, THIS_MODULE);
 480
 481        if (IS_ERR(info->rtc_dev)) {
 482                ret = PTR_ERR(info->rtc_dev);
 483                dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
 484                return ret;
 485        }
 486
 487        virq = irq_create_mapping(max8997->irq_domain, MAX8997_PMICIRQ_RTCA1);
 488        if (!virq) {
 489                dev_err(&pdev->dev, "Failed to create mapping alarm IRQ\n");
 490                ret = -ENXIO;
 491                goto err_out;
 492        }
 493        info->virq = virq;
 494
 495        ret = devm_request_threaded_irq(&pdev->dev, virq, NULL,
 496                                max8997_rtc_alarm_irq, 0,
 497                                "rtc-alarm0", info);
 498        if (ret < 0)
 499                dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
 500                        info->virq, ret);
 501
 502err_out:
 503        return ret;
 504}
 505
 506static void max8997_rtc_shutdown(struct platform_device *pdev)
 507{
 508        struct max8997_rtc_info *info = platform_get_drvdata(pdev);
 509
 510        max8997_rtc_enable_wtsr(info, false);
 511        max8997_rtc_enable_smpl(info, false);
 512}
 513
 514static const struct platform_device_id rtc_id[] = {
 515        { "max8997-rtc", 0 },
 516        {},
 517};
 518MODULE_DEVICE_TABLE(platform, rtc_id);
 519
 520static struct platform_driver max8997_rtc_driver = {
 521        .driver         = {
 522                .name   = "max8997-rtc",
 523        },
 524        .probe          = max8997_rtc_probe,
 525        .shutdown       = max8997_rtc_shutdown,
 526        .id_table       = rtc_id,
 527};
 528
 529module_platform_driver(max8997_rtc_driver);
 530
 531MODULE_DESCRIPTION("Maxim MAX8997 RTC driver");
 532MODULE_AUTHOR("<ms925.kim@samsung.com>");
 533MODULE_LICENSE("GPL");
 534