drivers/rtc/rtc-max77802.c

   1 /*
   2  * RTC driver for Maxim MAX77802
   3  *
   4  * Copyright (C) 2013 Google, Inc
   5  *
   6  * Copyright (C) 2012 Samsung Electronics Co.Ltd
   7  *
   8  *  based on rtc-max8997.c
   9  *
  10  *  This program is free software; you can redistribute  it and/or modify it
  11  *  under  the terms of  the GNU General  Public License as published by the
  12  *  Free Software Foundation;  either version 2 of the  License, or (at your
  13  *  option) any later version.
  14  *
  15  */
  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 /* For the RTCAE1 register, we write this value to enable the alarm */
  45 #define ALARM_ENABLE_VALUE              0x77
  46
  47 #define MAX77802_RTC_UPDATE_DELAY_US    200
  48
  49 enum {
  50         RTC_SEC = 0,
  51         RTC_MIN,
  52         RTC_HOUR,
  53         RTC_WEEKDAY,
  54         RTC_MONTH,
  55         RTC_YEAR,
  56         RTC_DATE,
  57         RTC_NR_TIME
  58 };
  59
  60 struct max77802_rtc_info {
  61         struct device           *dev;
  62         struct max77686_dev     *max77802;
  63         struct i2c_client       *rtc;
  64         struct rtc_device       *rtc_dev;
  65         struct mutex            lock;
  66
  67         struct regmap           *regmap;
  68
  69         int virq;
  70         int rtc_24hr_mode;
  71 };
  72
  73 enum MAX77802_RTC_OP {
  74         MAX77802_RTC_WRITE,
  75         MAX77802_RTC_READ,
  76 };
  77
  78 static void max77802_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
  79                                    int rtc_24hr_mode)
  80 {
  81         tm->tm_sec = data[RTC_SEC] & 0xff;
  82         tm->tm_min = data[RTC_MIN] & 0xff;
  83         if (rtc_24hr_mode)
  84                 tm->tm_hour = data[RTC_HOUR] & 0x1f;
  85         else {
  86                 tm->tm_hour = data[RTC_HOUR] & 0x0f;
  87                 if (data[RTC_HOUR] & HOUR_PM_MASK)
  88                         tm->tm_hour += 12;
  89         }
  90
  91         /* Only a single bit is set in data[], so fls() would be equivalent */
  92         tm->tm_wday = ffs(data[RTC_WEEKDAY] & 0xff) - 1;
  93         tm->tm_mday = data[RTC_DATE] & 0x1f;
  94         tm->tm_mon = (data[RTC_MONTH] & 0x0f) - 1;
  95
  96         tm->tm_year = data[RTC_YEAR] & 0xff;
  97         tm->tm_yday = 0;
  98         tm->tm_isdst = 0;
  99 }
 100
 101 static int max77802_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;
 110
 111         return 0;
 112 }
 113
 114 static int max77802_rtc_update(struct max77802_rtc_info *info,
 115         enum MAX77802_RTC_OP op)
 116 {
 117         int ret;
 118         unsigned int data;
 119
 120         if (op == MAX77802_RTC_WRITE)
 121                 data = 1 << RTC_UDR_SHIFT;
 122         else
 123                 data = 1 << RTC_RBUDR_SHIFT;
 124
 125         ret = regmap_update_bits(info->max77802->regmap,
 126                                  MAX77802_RTC_UPDATE0, data, data);
 127         if (ret < 0)
 128                 dev_err(info->dev, "%s: fail to write update reg(ret=%d, data=0x%x)\n",
 129                                 __func__, ret, data);
 130         else {
 131                 /* Minimum delay required before RTC update. */
 132                 usleep_range(MAX77802_RTC_UPDATE_DELAY_US,
 133                              MAX77802_RTC_UPDATE_DELAY_US * 2);
 134         }
 135
 136         return ret;
 137 }
 138
 139 static int max77802_rtc_read_time(struct device *dev, struct rtc_time *tm)
 140 {
 141         struct max77802_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 = max77802_rtc_update(info, MAX77802_RTC_READ);
 148         if (ret < 0)
 149                 goto out;
 150
 151         ret = regmap_bulk_read(info->max77802->regmap,
 152                                 MAX77802_RTC_SEC, data, RTC_NR_TIME);
 153         if (ret < 0) {
 154                 dev_err(info->dev, "%s: fail to read time reg(%d)\n", __func__,
 155                         ret);
 156                 goto out;
 157         }
 158
 159         max77802_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);
 160
 161         ret = rtc_valid_tm(tm);
 162
 163 out:
 164         mutex_unlock(&info->lock);
 165         return ret;
 166 }
 167
 168 static int max77802_rtc_set_time(struct device *dev, struct rtc_time *tm)
 169 {
 170         struct max77802_rtc_info *info = dev_get_drvdata(dev);
 171         u8 data[RTC_NR_TIME];
 172         int ret;
 173
 174         ret = max77802_rtc_tm_to_data(tm, data);
 175         if (ret < 0)
 176                 return ret;
 177
 178         mutex_lock(&info->lock);
 179
 180         ret = regmap_bulk_write(info->max77802->regmap,
 181                                  MAX77802_RTC_SEC, data, RTC_NR_TIME);
 182         if (ret < 0) {
 183                 dev_err(info->dev, "%s: fail to write time reg(%d)\n", __func__,
 184                         ret);
 185                 goto out;
 186         }
 187
 188         ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
 189
 190 out:
 191         mutex_unlock(&info->lock);
 192         return ret;
 193 }
 194
 195 static int max77802_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 196 {
 197         struct max77802_rtc_info *info = dev_get_drvdata(dev);
 198         u8 data[RTC_NR_TIME];
 199         unsigned int val;
 200         int ret;
 201
 202         mutex_lock(&info->lock);
 203
 204         ret = max77802_rtc_update(info, MAX77802_RTC_READ);
 205         if (ret < 0)
 206                 goto out;
 207
 208         ret = regmap_bulk_read(info->max77802->regmap,
 209                                  MAX77802_ALARM1_SEC, data, RTC_NR_TIME);
 210         if (ret < 0) {
 211                 dev_err(info->dev, "%s:%d fail to read alarm reg(%d)\n",
 212                                 __func__, __LINE__, ret);
 213                 goto out;
 214         }
 215
 216         max77802_rtc_data_to_tm(data, &alrm->time, info->rtc_24hr_mode);
 217
 218         alrm->enabled = 0;
 219         ret = regmap_read(info->max77802->regmap,
 220                           MAX77802_RTC_AE1, &val);
 221         if (ret < 0) {
 222                 dev_err(info->dev, "%s:%d fail to read alarm enable(%d)\n",
 223                         __func__, __LINE__, ret);
 224                 goto out;
 225         }
 226         if (val)
 227                 alrm->enabled = 1;
 228
 229         alrm->pending = 0;
 230         ret = regmap_read(info->max77802->regmap, MAX77802_REG_STATUS2, &val);
 231         if (ret < 0) {
 232                 dev_err(info->dev, "%s:%d fail to read status2 reg(%d)\n",
 233                                 __func__, __LINE__, ret);
 234                 goto out;
 235         }
 236
 237         if (val & (1 << 2)) /* RTCA1 */
 238                 alrm->pending = 1;
 239
 240 out:
 241         mutex_unlock(&info->lock);
 242         return 0;
 243 }
 244
 245 static int max77802_rtc_stop_alarm(struct max77802_rtc_info *info)
 246 {
 247         int ret;
 248
 249         if (!mutex_is_locked(&info->lock))
 250                 dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
 251
 252         ret = max77802_rtc_update(info, MAX77802_RTC_READ);
 253         if (ret < 0)
 254                 goto out;
 255
 256         ret = regmap_write(info->max77802->regmap,
 257                            MAX77802_RTC_AE1, 0);
 258         if (ret < 0) {
 259                 dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
 260                         __func__, ret);
 261                 goto out;
 262         }
 263
 264         ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
 265 out:
 266         return ret;
 267 }
 268
 269 static int max77802_rtc_start_alarm(struct max77802_rtc_info *info)
 270 {
 271         int ret;
 272
 273         if (!mutex_is_locked(&info->lock))
 274                 dev_warn(info->dev, "%s: should have mutex locked\n",
 275                          __func__);
 276
 277         ret = max77802_rtc_update(info, MAX77802_RTC_READ);
 278         if (ret < 0)
 279                 goto out;
 280
 281         ret = regmap_write(info->max77802->regmap,
 282                                    MAX77802_RTC_AE1,
 283                                    ALARM_ENABLE_VALUE);
 284
 285         if (ret < 0) {
 286                 dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
 287                                 __func__, ret);
 288                 goto out;
 289         }
 290
 291         ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
 292 out:
 293         return ret;
 294 }
 295
 296 static int max77802_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 297 {
 298         struct max77802_rtc_info *info = dev_get_drvdata(dev);
 299         u8 data[RTC_NR_TIME];
 300         int ret;
 301
 302         ret = max77802_rtc_tm_to_data(&alrm->time, data);
 303         if (ret < 0)
 304                 return ret;
 305
 306         mutex_lock(&info->lock);
 307
 308         ret = max77802_rtc_stop_alarm(info);
 309         if (ret < 0)
 310                 goto out;
 311
 312         ret = regmap_bulk_write(info->max77802->regmap,
 313                                  MAX77802_ALARM1_SEC, data, RTC_NR_TIME);
 314
 315         if (ret < 0) {
 316                 dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
 317                                 __func__, ret);
 318                 goto out;
 319         }
 320
 321         ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
 322         if (ret < 0)
 323                 goto out;
 324
 325         if (alrm->enabled)
 326                 ret = max77802_rtc_start_alarm(info);
 327 out:
 328         mutex_unlock(&info->lock);
 329         return ret;
 330 }
 331
 332 static int max77802_rtc_alarm_irq_enable(struct device *dev,
 333                                          unsigned int enabled)
 334 {
 335         struct max77802_rtc_info *info = dev_get_drvdata(dev);
 336         int ret;
 337
 338         mutex_lock(&info->lock);
 339         if (enabled)
 340                 ret = max77802_rtc_start_alarm(info);
 341         else
 342                 ret = max77802_rtc_stop_alarm(info);
 343         mutex_unlock(&info->lock);
 344
 345         return ret;
 346 }
 347
 348 static irqreturn_t max77802_rtc_alarm_irq(int irq, void *data)
 349 {
 350         struct max77802_rtc_info *info = data;
 351
 352         dev_dbg(info->dev, "%s:irq(%d)\n", __func__, irq);
 353
 354         rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
 355
 356         return IRQ_HANDLED;
 357 }
 358
 359 static const struct rtc_class_ops max77802_rtc_ops = {
 360         .read_time = max77802_rtc_read_time,
 361         .set_time = max77802_rtc_set_time,
 362         .read_alarm = max77802_rtc_read_alarm,
 363         .set_alarm = max77802_rtc_set_alarm,
 364         .alarm_irq_enable = max77802_rtc_alarm_irq_enable,
 365 };
 366
 367 static int max77802_rtc_init_reg(struct max77802_rtc_info *info)
 368 {
 369         u8 data[2];
 370         int ret;
 371
 372         max77802_rtc_update(info, MAX77802_RTC_READ);
 373
 374         /* Set RTC control register : Binary mode, 24hour mdoe */
 375         data[0] = (1 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
 376         data[1] = (0 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
 377
 378         info->rtc_24hr_mode = 1;
 379
 380         ret = regmap_bulk_write(info->max77802->regmap,
 381                                 MAX77802_RTC_CONTROLM, data, ARRAY_SIZE(data));
 382         if (ret < 0) {
 383                 dev_err(info->dev, "%s: fail to write controlm reg(%d)\n",
 384                                 __func__, ret);
 385                 return ret;
 386         }
 387
 388         ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
 389         return ret;
 390 }
 391
 392 static int max77802_rtc_probe(struct platform_device *pdev)
 393 {
 394         struct max77686_dev *max77802 = dev_get_drvdata(pdev->dev.parent);
 395         struct max77802_rtc_info *info;
 396         int ret;
 397
 398         dev_dbg(&pdev->dev, "%s\n", __func__);
 399
 400         info = devm_kzalloc(&pdev->dev, sizeof(struct max77802_rtc_info),
 401                             GFP_KERNEL);
 402         if (!info)
 403                 return -ENOMEM;
 404
 405         mutex_init(&info->lock);
 406         info->dev = &pdev->dev;
 407         info->max77802 = max77802;
 408         info->rtc = max77802->i2c;
 409
 410         platform_set_drvdata(pdev, info);
 411
 412         ret = max77802_rtc_init_reg(info);
 413
 414         if (ret < 0) {
 415                 dev_err(&pdev->dev, "Failed to initialize RTC reg:%d\n", ret);
 416                 return ret;
 417         }
 418
 419         device_init_wakeup(&pdev->dev, 1);
 420
 421         info->rtc_dev = devm_rtc_device_register(&pdev->dev, "max77802-rtc",
 422                                                  &max77802_rtc_ops, THIS_MODULE);
 423
 424         if (IS_ERR(info->rtc_dev)) {
 425                 ret = PTR_ERR(info->rtc_dev);
 426                 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
 427                 if (ret == 0)
 428                         ret = -EINVAL;
 429                 return ret;
 430         }
 431
 432         if (!max77802->rtc_irq_data) {
 433                 dev_err(&pdev->dev, "No RTC regmap IRQ chip\n");
 434                 return -EINVAL;
 435         }
 436
 437         info->virq = regmap_irq_get_virq(max77802->rtc_irq_data,
 438                                          MAX77686_RTCIRQ_RTCA1);
 439
 440         if (info->virq <= 0) {
 441                 dev_err(&pdev->dev, "Failed to get virtual IRQ %d\n",
 442                         MAX77686_RTCIRQ_RTCA1);
 443                 return -EINVAL;
 444         }
 445
 446         ret = devm_request_threaded_irq(&pdev->dev, info->virq, NULL,
 447                                         max77802_rtc_alarm_irq, 0, "rtc-alarm1",
 448                                         info);
 449         if (ret < 0)
 450                 dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
 451                         info->virq, ret);
 452
 453         return ret;
 454 }
 455
 456 #ifdef CONFIG_PM_SLEEP
 457 static int max77802_rtc_suspend(struct device *dev)
 458 {
 459         if (device_may_wakeup(dev)) {
 460                 struct max77802_rtc_info *info = dev_get_drvdata(dev);
 461
 462                 return enable_irq_wake(info->virq);
 463         }
 464
 465         return 0;
 466 }
 467
 468 static int max77802_rtc_resume(struct device *dev)
 469 {
 470         if (device_may_wakeup(dev)) {
 471                 struct max77802_rtc_info *info = dev_get_drvdata(dev);
 472
 473                 return disable_irq_wake(info->virq);
 474         }
 475
 476         return 0;
 477 }
 478 #endif
 479
 480 static SIMPLE_DEV_PM_OPS(max77802_rtc_pm_ops,
 481                          max77802_rtc_suspend, max77802_rtc_resume);
 482
 483 static const struct platform_device_id rtc_id[] = {
 484         { "max77802-rtc", 0 },
 485         {},
 486 };
 487
 488 static struct platform_driver max77802_rtc_driver = {
 489         .driver         = {
 490                 .name   = "max77802-rtc",
 491                 .pm     = &max77802_rtc_pm_ops,
 492         },
 493         .probe          = max77802_rtc_probe,
 494         .id_table       = rtc_id,
 495 };
 496
 497 module_platform_driver(max77802_rtc_driver);
 498
 499 MODULE_DESCRIPTION("Maxim MAX77802 RTC driver");
 500 MODULE_AUTHOR("Simon Glass <sjg@chromium.org>");
 501 MODULE_LICENSE("GPL");