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 int wm8350_rtc_update_irq_enable(struct device *dev,
 306                                         unsigned int enabled)
 307 {
 308         struct wm8350 *wm8350 = dev_get_drvdata(dev);
 309
 310         /* Suppress duplicate changes since genirq nests enable and
 311          * disable calls. */
 312         if (enabled == wm8350->rtc.update_enabled)
 313                 return 0;
 314
 315         if (enabled)
 316                 wm8350_unmask_irq(wm8350, WM8350_IRQ_RTC_SEC);
 317         else
 318                 wm8350_mask_irq(wm8350, WM8350_IRQ_RTC_SEC);
 319
 320         wm8350->rtc.update_enabled = enabled;
 321
 322         return 0;
 323 }
 324
 325 static irqreturn_t wm8350_rtc_alarm_handler(int irq, void *data)
 326 {
 327         struct wm8350 *wm8350 = data;
 328         struct rtc_device *rtc = wm8350->rtc.rtc;
 329         int ret;
 330
 331         rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
 332
 333         /* Make it one shot */
 334         ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL,
 335                               WM8350_RTC_ALMSET);
 336         if (ret != 0) {
 337                 dev_err(&(wm8350->rtc.pdev->dev),
 338                         "Failed to disable alarm: %d\n", ret);
 339         }
 340
 341         return IRQ_HANDLED;
 342 }
 343
 344 static irqreturn_t wm8350_rtc_update_handler(int irq, void *data)
 345 {
 346         struct wm8350 *wm8350 = data;
 347         struct rtc_device *rtc = wm8350->rtc.rtc;
 348
 349         rtc_update_irq(rtc, 1, RTC_IRQF | RTC_UF);
 350
 351         return IRQ_HANDLED;
 352 }
 353
 354 static const struct rtc_class_ops wm8350_rtc_ops = {
 355         .read_time = wm8350_rtc_readtime,
 356         .set_time = wm8350_rtc_settime,
 357         .read_alarm = wm8350_rtc_readalarm,
 358         .set_alarm = wm8350_rtc_setalarm,
 359         .alarm_irq_enable = wm8350_rtc_alarm_irq_enable,
 360         .update_irq_enable = wm8350_rtc_update_irq_enable,
 361 };
 362
 363 #ifdef CONFIG_PM
 364 static int wm8350_rtc_suspend(struct device *dev)
 365 {
 366         struct platform_device *pdev = to_platform_device(dev);
 367         struct wm8350 *wm8350 = dev_get_drvdata(&pdev->dev);
 368         int ret = 0;
 369         u16 reg;
 370
 371         reg = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
 372
 373         if (device_may_wakeup(&wm8350->rtc.pdev->dev) &&
 374             reg & WM8350_RTC_ALMSTS) {
 375                 ret = wm8350_rtc_stop_alarm(wm8350);
 376                 if (ret != 0)
 377                         dev_err(&pdev->dev, "Failed to stop RTC alarm: %d\n",
 378                                 ret);
 379         }
 380
 381         return ret;
 382 }
 383
 384 static int wm8350_rtc_resume(struct device *dev)
 385 {
 386         struct platform_device *pdev = to_platform_device(dev);
 387         struct wm8350 *wm8350 = dev_get_drvdata(&pdev->dev);
 388         int ret;
 389
 390         if (wm8350->rtc.alarm_enabled) {
 391                 ret = wm8350_rtc_start_alarm(wm8350);
 392                 if (ret != 0)
 393                         dev_err(&pdev->dev,
 394                                 "Failed to restart RTC alarm: %d\n", ret);
 395         }
 396
 397         return 0;
 398 }
 399
 400 #else
 401 #define wm8350_rtc_suspend NULL
 402 #define wm8350_rtc_resume NULL
 403 #endif
 404
 405 static int wm8350_rtc_probe(struct platform_device *pdev)
 406 {
 407         struct wm8350 *wm8350 = platform_get_drvdata(pdev);
 408         struct wm8350_rtc *wm_rtc = &wm8350->rtc;
 409         int ret = 0;
 410         u16 timectl, power5;
 411
 412         timectl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
 413         if (timectl & WM8350_RTC_BCD) {
 414                 dev_err(&pdev->dev, "RTC BCD mode not supported\n");
 415                 return -EINVAL;
 416         }
 417         if (timectl & WM8350_RTC_12HR) {
 418                 dev_err(&pdev->dev, "RTC 12 hour mode not supported\n");
 419                 return -EINVAL;
 420         }
 421
 422         /* enable the RTC if it's not already enabled */
 423         power5 = wm8350_reg_read(wm8350, WM8350_POWER_MGMT_5);
 424         if (!(power5 &  WM8350_RTC_TICK_ENA)) {
 425                 dev_info(wm8350->dev, "Starting RTC\n");
 426
 427                 wm8350_reg_unlock(wm8350);
 428
 429                 ret = wm8350_set_bits(wm8350, WM8350_POWER_MGMT_5,
 430                                       WM8350_RTC_TICK_ENA);
 431                 if (ret < 0) {
 432                         dev_err(&pdev->dev, "failed to enable RTC: %d\n", ret);
 433                         return ret;
 434                 }
 435
 436                 wm8350_reg_lock(wm8350);
 437         }
 438
 439         if (timectl & WM8350_RTC_STS) {
 440                 int retries;
 441
 442                 ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
 443                                         WM8350_RTC_SET);
 444                 if (ret < 0) {
 445                         dev_err(&pdev->dev, "failed to start: %d\n", ret);
 446                         return ret;
 447                 }
 448
 449                 retries = WM8350_SET_TIME_RETRIES;
 450                 do {
 451                         timectl = wm8350_reg_read(wm8350,
 452                                                   WM8350_RTC_TIME_CONTROL);
 453                 } while (timectl & WM8350_RTC_STS && --retries);
 454
 455                 if (retries == 0) {
 456                         dev_err(&pdev->dev, "failed to start: timeout\n");
 457                         return -ENODEV;
 458                 }
 459         }
 460
 461         device_init_wakeup(&pdev->dev, 1);
 462
 463         wm_rtc->rtc = rtc_device_register("wm8350", &pdev->dev,
 464                                           &wm8350_rtc_ops, THIS_MODULE);
 465         if (IS_ERR(wm_rtc->rtc)) {
 466                 ret = PTR_ERR(wm_rtc->rtc);
 467                 dev_err(&pdev->dev, "failed to register RTC: %d\n", ret);
 468                 return ret;
 469         }
 470
 471         wm8350_register_irq(wm8350, WM8350_IRQ_RTC_SEC,
 472                             wm8350_rtc_update_handler, 0,
 473                             "RTC Seconds", wm8350);
 474         wm8350_mask_irq(wm8350, WM8350_IRQ_RTC_SEC);
 475
 476         wm8350_register_irq(wm8350, WM8350_IRQ_RTC_ALM,
 477                             wm8350_rtc_alarm_handler, 0,
 478                             "RTC Alarm", wm8350);
 479
 480         return 0;
 481 }
 482
 483 static int __devexit wm8350_rtc_remove(struct platform_device *pdev)
 484 {
 485         struct wm8350 *wm8350 = platform_get_drvdata(pdev);
 486         struct wm8350_rtc *wm_rtc = &wm8350->rtc;
 487
 488         wm8350_free_irq(wm8350, WM8350_IRQ_RTC_SEC, wm8350);
 489         wm8350_free_irq(wm8350, WM8350_IRQ_RTC_ALM, wm8350);
 490
 491         rtc_device_unregister(wm_rtc->rtc);
 492
 493         return 0;
 494 }
 495
 496 static struct dev_pm_ops wm8350_rtc_pm_ops = {
 497         .suspend = wm8350_rtc_suspend,
 498         .resume = wm8350_rtc_resume,
 499 };
 500
 501 static struct platform_driver wm8350_rtc_driver = {
 502         .probe = wm8350_rtc_probe,
 503         .remove = __devexit_p(wm8350_rtc_remove),
 504         .driver = {
 505                 .name = "wm8350-rtc",
 506                 .pm = &wm8350_rtc_pm_ops,
 507         },
 508 };
 509
 510 static int __init wm8350_rtc_init(void)
 511 {
 512         return platform_driver_register(&wm8350_rtc_driver);
 513 }
 514 module_init(wm8350_rtc_init);
 515
 516 static void __exit wm8350_rtc_exit(void)
 517 {
 518         platform_driver_unregister(&wm8350_rtc_driver);
 519 }
 520 module_exit(wm8350_rtc_exit);
 521
 522 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 523 MODULE_DESCRIPTION("RTC driver for the WM8350");
 524 MODULE_LICENSE("GPL");
 525 MODULE_ALIAS("platform:wm8350-rtc");