drivers/rtc/rtc-wm8350.c

   1 /*
   2  *      Real Time Clock driver for Wolfson Microelectronics WM8350
   3  *
   4  *      Copyright (C) 2007, 2008 Wolfson Microelectronics PLC.
   5  *
   6  *  Author: Liam Girdwood
   7  *          linux@wolfsonmicro.com
   8  *
   9  *  This program is free software; you can redistribute  it and/or modify it
  10  *  under  the terms of  the GNU General  Public License as published by the
  11  *  Free Software Foundation;  either version 2 of the  License, or (at your
  12  *  option) any later version.
  13  *
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/kernel.h>
  18 #include <linux/time.h>
  19 #include <linux/rtc.h>
  20 #include <linux/bcd.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/ioctl.h>
  23 #include <linux/completion.h>
  24 #include <linux/mfd/wm8350/rtc.h>
  25 #include <linux/mfd/wm8350/core.h>
  26 #include <linux/delay.h>
  27 #include <linux/platform_device.h>
  28
  29 #define WM8350_SET_ALM_RETRIES  5
  30 #define WM8350_SET_TIME_RETRIES 5
  31 #define WM8350_GET_TIME_RETRIES 5
  32
  33 #define to_wm8350_from_rtc_dev(d) container_of(d, struct wm8350, rtc.pdev.dev)
  34
  35 /*
  36  * Read current time and date in RTC
  37  */
  38 static int wm8350_rtc_readtime(struct device *dev, struct rtc_time *tm)
  39 {
  40         struct wm8350 *wm8350 = dev_get_drvdata(dev);
  41         u16 time1[4], time2[4];
  42         int retries = WM8350_GET_TIME_RETRIES, ret;
  43
  44         /*
  45          * Read the time twice and compare.
  46          * If time1 == time2, then time is valid else retry.
  47          */
  48         do {
  49                 ret = wm8350_block_read(wm8350, WM8350_RTC_SECONDS_MINUTES,
  50                                         4, time1);
  51                 if (ret < 0)
  52                         return ret;
  53                 ret = wm8350_block_read(wm8350, WM8350_RTC_SECONDS_MINUTES,
  54                                         4, time2);
  55                 if (ret < 0)
  56                         return ret;
  57
  58                 if (memcmp(time1, time2, sizeof(time1)) == 0) {
  59                         tm->tm_sec = time1[0] & WM8350_RTC_SECS_MASK;
  60
  61                         tm->tm_min = (time1[0] & WM8350_RTC_MINS_MASK)
  62                             >> WM8350_RTC_MINS_SHIFT;
  63
  64                         tm->tm_hour = time1[1] & WM8350_RTC_HRS_MASK;
  65
  66                         tm->tm_wday = ((time1[1] >> WM8350_RTC_DAY_SHIFT)
  67                                        & 0x7) - 1;
  68
  69                         tm->tm_mon = ((time1[2] & WM8350_RTC_MTH_MASK)
  70                                       >> WM8350_RTC_MTH_SHIFT) - 1;
  71
  72                         tm->tm_mday = (time1[2] & WM8350_RTC_DATE_MASK);
  73
  74                         tm->tm_year = ((time1[3] & WM8350_RTC_YHUNDREDS_MASK)
  75                                        >> WM8350_RTC_YHUNDREDS_SHIFT) * 100;
  76                         tm->tm_year += time1[3] & WM8350_RTC_YUNITS_MASK;
  77
  78                         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon,
  79                                                     tm->tm_year);
  80                         tm->tm_year -= 1900;
  81
  82                         dev_dbg(dev, "Read (%d left): %04x %04x %04x %04x\n",
  83                                 retries,
  84                                 time1[0], time1[1], time1[2], time1[3]);
  85
  86                         return 0;
  87                 }
  88         } while (retries--);
  89
  90         dev_err(dev, "timed out reading RTC time\n");
  91         return -EIO;
  92 }
  93
  94 /*
  95  * Set current time and date in RTC
  96  */
  97 static int wm8350_rtc_settime(struct device *dev, struct rtc_time *tm)
  98 {
  99         struct wm8350 *wm8350 = dev_get_drvdata(dev);
 100         u16 time[4];
 101         u16 rtc_ctrl;
 102         int ret, retries = WM8350_SET_TIME_RETRIES;
 103
 104         time[0] = tm->tm_sec;
 105         time[0] |= tm->tm_min << WM8350_RTC_MINS_SHIFT;
 106         time[1] = tm->tm_hour;
 107         time[1] |= (tm->tm_wday + 1) << WM8350_RTC_DAY_SHIFT;
 108         time[2] = tm->tm_mday;
 109         time[2] |= (tm->tm_mon + 1) << WM8350_RTC_MTH_SHIFT;
 110         time[3] = ((tm->tm_year + 1900) / 100) << WM8350_RTC_YHUNDREDS_SHIFT;
 111         time[3] |= (tm->tm_year + 1900) % 100;
 112
 113         dev_dbg(dev, "Setting: %04x %04x %04x %04x\n",
 114                 time[0], time[1], time[2], time[3]);
 115
 116         /* Set RTC_SET to stop the clock */
 117         ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL, WM8350_RTC_SET);
 118         if (ret < 0)
 119                 return ret;
 120
 121         /* Wait until confirmation of stopping */
 122         do {
 123                 rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
 124                 schedule_timeout_uninterruptible(msecs_to_jiffies(1));
 125         } while (--retries && !(rtc_ctrl & WM8350_RTC_STS));
 126
 127         if (!retries) {
 128                 dev_err(dev, "timed out on set confirmation\n");
 129                 return -EIO;
 130         }
 131
 132         /* Write time to RTC */
 133         ret = wm8350_block_write(wm8350, WM8350_RTC_SECONDS_MINUTES, 4, time);
 134         if (ret < 0)
 135                 return ret;
 136
 137         /* Clear RTC_SET to start the clock */
 138         ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
 139                                 WM8350_RTC_SET);
 140         return ret;
 141 }
 142
 143 /*
 144  * Read alarm time and date in RTC
 145  */
 146 static int wm8350_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 147 {
 148         struct wm8350 *wm8350 = dev_get_drvdata(dev);
 149         struct rtc_time *tm = &alrm->time;
 150         u16 time[4];
 151         int ret;
 152
 153         ret = wm8350_block_read(wm8350, WM8350_ALARM_SECONDS_MINUTES, 4, time);
 154         if (ret < 0)
 155                 return ret;
 156
 157         tm->tm_sec = time[0] & WM8350_RTC_ALMSECS_MASK;
 158         if (tm->tm_sec == WM8350_RTC_ALMSECS_MASK)
 159                 tm->tm_sec = -1;
 160
 161         tm->tm_min = time[0] & WM8350_RTC_ALMMINS_MASK;
 162         if (tm->tm_min == WM8350_RTC_ALMMINS_MASK)
 163                 tm->tm_min = -1;
 164         else
 165                 tm->tm_min >>= WM8350_RTC_ALMMINS_SHIFT;
 166
 167         tm->tm_hour = time[1] & WM8350_RTC_ALMHRS_MASK;
 168         if (tm->tm_hour == WM8350_RTC_ALMHRS_MASK)
 169                 tm->tm_hour = -1;
 170
 171         tm->tm_wday = ((time[1] >> WM8350_RTC_ALMDAY_SHIFT) & 0x7) - 1;
 172         if (tm->tm_wday > 7)
 173                 tm->tm_wday = -1;
 174
 175         tm->tm_mon = time[2] & WM8350_RTC_ALMMTH_MASK;
 176         if (tm->tm_mon == WM8350_RTC_ALMMTH_MASK)
 177                 tm->tm_mon = -1;
 178         else
 179                 tm->tm_mon = (tm->tm_mon >> WM8350_RTC_ALMMTH_SHIFT) - 1;
 180
 181         tm->tm_mday = (time[2] & WM8350_RTC_ALMDATE_MASK);
 182         if (tm->tm_mday == WM8350_RTC_ALMDATE_MASK)
 183                 tm->tm_mday = -1;
 184
 185         tm->tm_year = -1;
 186
 187         alrm->enabled = !(time[3] & WM8350_RTC_ALMSTS);
 188
 189         return 0;
 190 }
 191
 192 static int wm8350_rtc_stop_alarm(struct wm8350 *wm8350)
 193 {
 194         int retries = WM8350_SET_ALM_RETRIES;
 195         u16 rtc_ctrl;
 196         int ret;
 197
 198         /* Set RTC_SET to stop the clock */
 199         ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL,
 200                               WM8350_RTC_ALMSET);
 201         if (ret < 0)
 202                 return ret;
 203
 204         /* Wait until confirmation of stopping */
 205         do {
 206                 rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
 207                 schedule_timeout_uninterruptible(msecs_to_jiffies(1));
 208         } while (retries-- && !(rtc_ctrl & WM8350_RTC_ALMSTS));
 209
 210         if (!(rtc_ctrl & WM8350_RTC_ALMSTS))
 211                 return -ETIMEDOUT;
 212
 213         return 0;
 214 }
 215
 216 static int wm8350_rtc_start_alarm(struct wm8350 *wm8350)
 217 {
 218         int ret;
 219         int retries = WM8350_SET_ALM_RETRIES;
 220         u16 rtc_ctrl;
 221
 222         ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
 223                                 WM8350_RTC_ALMSET);
 224         if (ret < 0)
 225                 return ret;
 226
 227         /* Wait until confirmation */
 228         do {
 229                 rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
 230                 schedule_timeout_uninterruptible(msecs_to_jiffies(1));
 231         } while (retries-- && rtc_ctrl & WM8350_RTC_ALMSTS);
 232
 233         if (rtc_ctrl & WM8350_RTC_ALMSTS)
 234                 return -ETIMEDOUT;
 235
 236         return 0;
 237 }
 238
 239 static int wm8350_rtc_alarm_irq_enable(struct device *dev,
 240                                        unsigned int enabled)
 241 {
 242         struct wm8350 *wm8350 = dev_get_drvdata(dev);
 243
 244         if (enabled)
 245                 return wm8350_rtc_start_alarm(wm8350);
 246         else
 247                 return wm8350_rtc_stop_alarm(wm8350);
 248 }
 249
 250 static int wm8350_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 251 {
 252         struct wm8350 *wm8350 = dev_get_drvdata(dev);
 253         struct rtc_time *tm = &alrm->time;
 254         u16 time[3];
 255         int ret;
 256
 257         memset(time, 0, sizeof(time));
 258
 259         if (tm->tm_sec != -1)
 260                 time[0] |= tm->tm_sec;
 261         else
 262                 time[0] |= WM8350_RTC_ALMSECS_MASK;
 263
 264         if (tm->tm_min != -1)
 265                 time[0] |= tm->tm_min << WM8350_RTC_ALMMINS_SHIFT;
 266         else
 267                 time[0] |= WM8350_RTC_ALMMINS_MASK;
 268
 269         if (tm->tm_hour != -1)
 270                 time[1] |= tm->tm_hour;
 271         else
 272                 time[1] |= WM8350_RTC_ALMHRS_MASK;
 273
 274         if (tm->tm_wday != -1)
 275                 time[1] |= (tm->tm_wday + 1) << WM8350_RTC_ALMDAY_SHIFT;
 276         else
 277                 time[1] |= WM8350_RTC_ALMDAY_MASK;
 278
 279         if (tm->tm_mday != -1)
 280                 time[2] |= tm->tm_mday;
 281         else
 282                 time[2] |= WM8350_RTC_ALMDATE_MASK;
 283
 284         if (tm->tm_mon != -1)
 285                 time[2] |= (tm->tm_mon + 1) << WM8350_RTC_ALMMTH_SHIFT;
 286         else
 287                 time[2] |= WM8350_RTC_ALMMTH_MASK;
 288
 289         ret = wm8350_rtc_stop_alarm(wm8350);
 290         if (ret < 0)
 291                 return ret;
 292
 293         /* Write time to RTC */
 294         ret = wm8350_block_write(wm8350, WM8350_ALARM_SECONDS_MINUTES,
 295                                  3, time);
 296         if (ret < 0)
 297                 return ret;
 298
 299         if (alrm->enabled)
 300                 ret = wm8350_rtc_start_alarm(wm8350);
 301
 302         return ret;
 303 }
 304
 305 static irqreturn_t wm8350_rtc_alarm_handler(int irq, void *data)
 306 {
 307         struct wm8350 *wm8350 = data;
 308         struct rtc_device *rtc = wm8350->rtc.rtc;
 309         int ret;
 310
 311         rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
 312
 313         /* Make it one shot */
 314         ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL,
 315                               WM8350_RTC_ALMSET);
 316         if (ret != 0) {
 317                 dev_err(&(wm8350->rtc.pdev->dev),
 318                         "Failed to disable alarm: %d\n", ret);
 319         }
 320
 321         return IRQ_HANDLED;
 322 }
 323
 324 static irqreturn_t wm8350_rtc_update_handler(int irq, void *data)
 325 {
 326         struct wm8350 *wm8350 = data;
 327         struct rtc_device *rtc = wm8350->rtc.rtc;
 328
 329         rtc_update_irq(rtc, 1, RTC_IRQF | RTC_UF);
 330
 331         return IRQ_HANDLED;
 332 }
 333
 334 static const struct rtc_class_ops wm8350_rtc_ops = {
 335         .read_time = wm8350_rtc_readtime,
 336         .set_time = wm8350_rtc_settime,
 337         .read_alarm = wm8350_rtc_readalarm,
 338         .set_alarm = wm8350_rtc_setalarm,
 339         .alarm_irq_enable = wm8350_rtc_alarm_irq_enable,
 340 };
 341
 342 #ifdef CONFIG_PM
 343 static int wm8350_rtc_suspend(struct device *dev)
 344 {
 345         struct platform_device *pdev = to_platform_device(dev);
 346         struct wm8350 *wm8350 = dev_get_drvdata(&pdev->dev);
 347         int ret = 0;
 348         u16 reg;
 349
 350         reg = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
 351
 352         if (device_may_wakeup(&wm8350->rtc.pdev->dev) &&
 353             reg & WM8350_RTC_ALMSTS) {
 354                 ret = wm8350_rtc_stop_alarm(wm8350);
 355                 if (ret != 0)
 356                         dev_err(&pdev->dev, "Failed to stop RTC alarm: %d\n",
 357                                 ret);
 358         }
 359
 360         return ret;
 361 }
 362
 363 static int wm8350_rtc_resume(struct device *dev)
 364 {
 365         struct platform_device *pdev = to_platform_device(dev);
 366         struct wm8350 *wm8350 = dev_get_drvdata(&pdev->dev);
 367         int ret;
 368
 369         if (wm8350->rtc.alarm_enabled) {
 370                 ret = wm8350_rtc_start_alarm(wm8350);
 371                 if (ret != 0)
 372                         dev_err(&pdev->dev,
 373                                 "Failed to restart RTC alarm: %d\n", ret);
 374         }
 375
 376         return 0;
 377 }
 378
 379 #else
 380 #define wm8350_rtc_suspend NULL
 381 #define wm8350_rtc_resume NULL
 382 #endif
 383
 384 static int wm8350_rtc_probe(struct platform_device *pdev)
 385 {
 386         struct wm8350 *wm8350 = platform_get_drvdata(pdev);
 387         struct wm8350_rtc *wm_rtc = &wm8350->rtc;
 388         int ret = 0;
 389         u16 timectl, power5;
 390
 391         timectl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
 392         if (timectl & WM8350_RTC_BCD) {
 393                 dev_err(&pdev->dev, "RTC BCD mode not supported\n");
 394                 return -EINVAL;
 395         }
 396         if (timectl & WM8350_RTC_12HR) {
 397                 dev_err(&pdev->dev, "RTC 12 hour mode not supported\n");
 398                 return -EINVAL;
 399         }
 400
 401         /* enable the RTC if it's not already enabled */
 402         power5 = wm8350_reg_read(wm8350, WM8350_POWER_MGMT_5);
 403         if (!(power5 &  WM8350_RTC_TICK_ENA)) {
 404                 dev_info(wm8350->dev, "Starting RTC\n");
 405
 406                 wm8350_reg_unlock(wm8350);
 407
 408                 ret = wm8350_set_bits(wm8350, WM8350_POWER_MGMT_5,
 409                                       WM8350_RTC_TICK_ENA);
 410                 if (ret < 0) {
 411                         dev_err(&pdev->dev, "failed to enable RTC: %d\n", ret);
 412                         return ret;
 413                 }
 414
 415                 wm8350_reg_lock(wm8350);
 416         }
 417
 418         if (timectl & WM8350_RTC_STS) {
 419                 int retries;
 420
 421                 ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
 422                                         WM8350_RTC_SET);
 423                 if (ret < 0) {
 424                         dev_err(&pdev->dev, "failed to start: %d\n", ret);
 425                         return ret;
 426                 }
 427
 428                 retries = WM8350_SET_TIME_RETRIES;
 429                 do {
 430                         timectl = wm8350_reg_read(wm8350,
 431                                                   WM8350_RTC_TIME_CONTROL);
 432                 } while (timectl & WM8350_RTC_STS && --retries);
 433
 434                 if (retries == 0) {
 435                         dev_err(&pdev->dev, "failed to start: timeout\n");
 436                         return -ENODEV;
 437                 }
 438         }
 439
 440         device_init_wakeup(&pdev->dev, 1);
 441
 442         wm_rtc->rtc = rtc_device_register("wm8350", &pdev->dev,
 443                                           &wm8350_rtc_ops, THIS_MODULE);
 444         if (IS_ERR(wm_rtc->rtc)) {
 445                 ret = PTR_ERR(wm_rtc->rtc);
 446                 dev_err(&pdev->dev, "failed to register RTC: %d\n", ret);
 447                 return ret;
 448         }
 449
 450         wm8350_register_irq(wm8350, WM8350_IRQ_RTC_SEC,
 451                             wm8350_rtc_update_handler, 0,
 452                             "RTC Seconds", wm8350);
 453         wm8350_mask_irq(wm8350, WM8350_IRQ_RTC_SEC);
 454
 455         wm8350_register_irq(wm8350, WM8350_IRQ_RTC_ALM,
 456                             wm8350_rtc_alarm_handler, 0,
 457                             "RTC Alarm", wm8350);
 458
 459         return 0;
 460 }
 461
 462 static int __devexit wm8350_rtc_remove(struct platform_device *pdev)
 463 {
 464         struct wm8350 *wm8350 = platform_get_drvdata(pdev);
 465         struct wm8350_rtc *wm_rtc = &wm8350->rtc;
 466
 467         wm8350_free_irq(wm8350, WM8350_IRQ_RTC_SEC, wm8350);
 468         wm8350_free_irq(wm8350, WM8350_IRQ_RTC_ALM, wm8350);
 469
 470         rtc_device_unregister(wm_rtc->rtc);
 471
 472         return 0;
 473 }
 474
 475 static struct dev_pm_ops wm8350_rtc_pm_ops = {
 476         .suspend = wm8350_rtc_suspend,
 477         .resume = wm8350_rtc_resume,
 478 };
 479
 480 static struct platform_driver wm8350_rtc_driver = {
 481         .probe = wm8350_rtc_probe,
 482         .remove = __devexit_p(wm8350_rtc_remove),
 483         .driver = {
 484                 .name = "wm8350-rtc",
 485                 .pm = &wm8350_rtc_pm_ops,
 486         },
 487 };
 488
 489 static int __init wm8350_rtc_init(void)
 490 {
 491         return platform_driver_register(&wm8350_rtc_driver);
 492 }
 493 module_init(wm8350_rtc_init);
 494
 495 static void __exit wm8350_rtc_exit(void)
 496 {
 497         platform_driver_unregister(&wm8350_rtc_driver);
 498 }
 499 module_exit(wm8350_rtc_exit);
 500
 501 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 502 MODULE_DESCRIPTION("RTC driver for the WM8350");
 503 MODULE_LICENSE("GPL");
 504 MODULE_ALIAS("platform:wm8350-rtc");