drivers/rtc/rtc-wm831x.c

   1 /*
   2  *      Real Time Clock driver for Wolfson Microelectronics WM831x
   3  *
   4  *      Copyright (C) 2009 Wolfson Microelectronics PLC.
   5  *
   6  *  Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   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/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/time.h>
  18 #include <linux/rtc.h>
  19 #include <linux/bcd.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/ioctl.h>
  22 #include <linux/completion.h>
  23 #include <linux/mfd/wm831x/core.h>
  24 #include <linux/delay.h>
  25 #include <linux/platform_device.h>
  26
  27
  28 /*
  29  * R16416 (0x4020) - RTC Write Counter
  30  */
  31 #define WM831X_RTC_WR_CNT_MASK                  0xFFFF  /* RTC_WR_CNT - [15:0] */
  32 #define WM831X_RTC_WR_CNT_SHIFT                      0  /* RTC_WR_CNT - [15:0] */
  33 #define WM831X_RTC_WR_CNT_WIDTH                     16  /* RTC_WR_CNT - [15:0] */
  34
  35 /*
  36  * R16417 (0x4021) - RTC Time 1
  37  */
  38 #define WM831X_RTC_TIME_MASK                    0xFFFF  /* RTC_TIME - [15:0] */
  39 #define WM831X_RTC_TIME_SHIFT                        0  /* RTC_TIME - [15:0] */
  40 #define WM831X_RTC_TIME_WIDTH                       16  /* RTC_TIME - [15:0] */
  41
  42 /*
  43  * R16418 (0x4022) - RTC Time 2
  44  */
  45 #define WM831X_RTC_TIME_MASK                    0xFFFF  /* RTC_TIME - [15:0] */
  46 #define WM831X_RTC_TIME_SHIFT                        0  /* RTC_TIME - [15:0] */
  47 #define WM831X_RTC_TIME_WIDTH                       16  /* RTC_TIME - [15:0] */
  48
  49 /*
  50  * R16419 (0x4023) - RTC Alarm 1
  51  */
  52 #define WM831X_RTC_ALM_MASK                     0xFFFF  /* RTC_ALM - [15:0] */
  53 #define WM831X_RTC_ALM_SHIFT                         0  /* RTC_ALM - [15:0] */
  54 #define WM831X_RTC_ALM_WIDTH                        16  /* RTC_ALM - [15:0] */
  55
  56 /*
  57  * R16420 (0x4024) - RTC Alarm 2
  58  */
  59 #define WM831X_RTC_ALM_MASK                     0xFFFF  /* RTC_ALM - [15:0] */
  60 #define WM831X_RTC_ALM_SHIFT                         0  /* RTC_ALM - [15:0] */
  61 #define WM831X_RTC_ALM_WIDTH                        16  /* RTC_ALM - [15:0] */
  62
  63 /*
  64  * R16421 (0x4025) - RTC Control
  65  */
  66 #define WM831X_RTC_VALID                        0x8000  /* RTC_VALID */
  67 #define WM831X_RTC_VALID_MASK                   0x8000  /* RTC_VALID */
  68 #define WM831X_RTC_VALID_SHIFT                      15  /* RTC_VALID */
  69 #define WM831X_RTC_VALID_WIDTH                       1  /* RTC_VALID */
  70 #define WM831X_RTC_SYNC_BUSY                    0x4000  /* RTC_SYNC_BUSY */
  71 #define WM831X_RTC_SYNC_BUSY_MASK               0x4000  /* RTC_SYNC_BUSY */
  72 #define WM831X_RTC_SYNC_BUSY_SHIFT                  14  /* RTC_SYNC_BUSY */
  73 #define WM831X_RTC_SYNC_BUSY_WIDTH                   1  /* RTC_SYNC_BUSY */
  74 #define WM831X_RTC_ALM_ENA                      0x0400  /* RTC_ALM_ENA */
  75 #define WM831X_RTC_ALM_ENA_MASK                 0x0400  /* RTC_ALM_ENA */
  76 #define WM831X_RTC_ALM_ENA_SHIFT                    10  /* RTC_ALM_ENA */
  77 #define WM831X_RTC_ALM_ENA_WIDTH                     1  /* RTC_ALM_ENA */
  78 #define WM831X_RTC_PINT_FREQ_MASK               0x0070  /* RTC_PINT_FREQ - [6:4] */
  79 #define WM831X_RTC_PINT_FREQ_SHIFT                   4  /* RTC_PINT_FREQ - [6:4] */
  80 #define WM831X_RTC_PINT_FREQ_WIDTH                   3  /* RTC_PINT_FREQ - [6:4] */
  81
  82 /*
  83  * R16422 (0x4026) - RTC Trim
  84  */
  85 #define WM831X_RTC_TRIM_MASK                    0x03FF  /* RTC_TRIM - [9:0] */
  86 #define WM831X_RTC_TRIM_SHIFT                        0  /* RTC_TRIM - [9:0] */
  87 #define WM831X_RTC_TRIM_WIDTH                       10  /* RTC_TRIM - [9:0] */
  88
  89 #define WM831X_SET_TIME_RETRIES 5
  90 #define WM831X_GET_TIME_RETRIES 5
  91
  92 struct wm831x_rtc {
  93         struct wm831x *wm831x;
  94         struct rtc_device *rtc;
  95         unsigned int alarm_enabled:1;
  96 };
  97
  98 /*
  99  * Read current time and date in RTC
 100  */
 101 static int wm831x_rtc_readtime(struct device *dev, struct rtc_time *tm)
 102 {
 103         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
 104         struct wm831x *wm831x = wm831x_rtc->wm831x;
 105         u16 time1[2], time2[2];
 106         int ret;
 107         int count = 0;
 108
 109         /* Has the RTC been programmed? */
 110         ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
 111         if (ret < 0) {
 112                 dev_err(dev, "Failed to read RTC control: %d\n", ret);
 113                 return ret;
 114         }
 115         if (!(ret & WM831X_RTC_VALID)) {
 116                 dev_dbg(dev, "RTC not yet configured\n");
 117                 return -EINVAL;
 118         }
 119
 120         /* Read twice to make sure we don't read a corrupt, partially
 121          * incremented, value.
 122          */
 123         do {
 124                 ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1,
 125                                        2, time1);
 126                 if (ret != 0)
 127                         continue;
 128
 129                 ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1,
 130                                        2, time2);
 131                 if (ret != 0)
 132                         continue;
 133
 134                 if (memcmp(time1, time2, sizeof(time1)) == 0) {
 135                         u32 time = (time1[0] << 16) | time1[1];
 136
 137                         rtc_time_to_tm(time, tm);
 138                         return rtc_valid_tm(tm);
 139                 }
 140
 141         } while (++count < WM831X_GET_TIME_RETRIES);
 142
 143         dev_err(dev, "Timed out reading current time\n");
 144
 145         return -EIO;
 146 }
 147
 148 /*
 149  * Set current time and date in RTC
 150  */
 151 static int wm831x_rtc_set_mmss(struct device *dev, unsigned long time)
 152 {
 153         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
 154         struct wm831x *wm831x = wm831x_rtc->wm831x;
 155         struct rtc_time new_tm;
 156         unsigned long new_time;
 157         int ret;
 158         int count = 0;
 159
 160         ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_1,
 161                                (time >> 16) & 0xffff);
 162         if (ret < 0) {
 163                 dev_err(dev, "Failed to write TIME_1: %d\n", ret);
 164                 return ret;
 165         }
 166
 167         ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_2, time & 0xffff);
 168         if (ret < 0) {
 169                 dev_err(dev, "Failed to write TIME_2: %d\n", ret);
 170                 return ret;
 171         }
 172
 173         /* Wait for the update to complete - should happen first time
 174          * round but be conservative.
 175          */
 176         do {
 177                 msleep(1);
 178
 179                 ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
 180                 if (ret < 0)
 181                         ret = WM831X_RTC_SYNC_BUSY;
 182         } while (!(ret & WM831X_RTC_SYNC_BUSY) &&
 183                  ++count < WM831X_SET_TIME_RETRIES);
 184
 185         if (ret & WM831X_RTC_SYNC_BUSY) {
 186                 dev_err(dev, "Timed out writing RTC update\n");
 187                 return -EIO;
 188         }
 189
 190         /* Check that the update was accepted; security features may
 191          * have caused the update to be ignored.
 192          */
 193         ret = wm831x_rtc_readtime(dev, &new_tm);
 194         if (ret < 0)
 195                 return ret;
 196
 197         ret = rtc_tm_to_time(&new_tm, &new_time);
 198         if (ret < 0) {
 199                 dev_err(dev, "Failed to convert time: %d\n", ret);
 200                 return ret;
 201         }
 202
 203         /* Allow a second of change in case of tick */
 204         if (new_time - time > 1) {
 205                 dev_err(dev, "RTC update not permitted by hardware\n");
 206                 return -EPERM;
 207         }
 208
 209         return 0;
 210 }
 211
 212 /*
 213  * Read alarm time and date in RTC
 214  */
 215 static int wm831x_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 216 {
 217         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
 218         int ret;
 219         u16 data[2];
 220         u32 time;
 221
 222         ret = wm831x_bulk_read(wm831x_rtc->wm831x, WM831X_RTC_ALARM_1,
 223                                2, data);
 224         if (ret != 0) {
 225                 dev_err(dev, "Failed to read alarm time: %d\n", ret);
 226                 return ret;
 227         }
 228
 229         time = (data[0] << 16) | data[1];
 230
 231         rtc_time_to_tm(time, &alrm->time);
 232
 233         ret = wm831x_reg_read(wm831x_rtc->wm831x, WM831X_RTC_CONTROL);
 234         if (ret < 0) {
 235                 dev_err(dev, "Failed to read RTC control: %d\n", ret);
 236                 return ret;
 237         }
 238
 239         if (ret & WM831X_RTC_ALM_ENA)
 240                 alrm->enabled = 1;
 241         else
 242                 alrm->enabled = 0;
 243
 244         return 0;
 245 }
 246
 247 static int wm831x_rtc_stop_alarm(struct wm831x_rtc *wm831x_rtc)
 248 {
 249         wm831x_rtc->alarm_enabled = 0;
 250
 251         return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
 252                                WM831X_RTC_ALM_ENA, 0);
 253 }
 254
 255 static int wm831x_rtc_start_alarm(struct wm831x_rtc *wm831x_rtc)
 256 {
 257         wm831x_rtc->alarm_enabled = 1;
 258
 259         return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
 260                                WM831X_RTC_ALM_ENA, WM831X_RTC_ALM_ENA);
 261 }
 262
 263 static int wm831x_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 264 {
 265         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
 266         struct wm831x *wm831x = wm831x_rtc->wm831x;
 267         int ret;
 268         unsigned long time;
 269
 270         ret = rtc_tm_to_time(&alrm->time, &time);
 271         if (ret < 0) {
 272                 dev_err(dev, "Failed to convert time: %d\n", ret);
 273                 return ret;
 274         }
 275
 276         ret = wm831x_rtc_stop_alarm(wm831x_rtc);
 277         if (ret < 0) {
 278                 dev_err(dev, "Failed to stop alarm: %d\n", ret);
 279                 return ret;
 280         }
 281
 282         ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_1,
 283                                (time >> 16) & 0xffff);
 284         if (ret < 0) {
 285                 dev_err(dev, "Failed to write ALARM_1: %d\n", ret);
 286                 return ret;
 287         }
 288
 289         ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_2, time & 0xffff);
 290         if (ret < 0) {
 291                 dev_err(dev, "Failed to write ALARM_2: %d\n", ret);
 292                 return ret;
 293         }
 294
 295         if (alrm->enabled) {
 296                 ret = wm831x_rtc_start_alarm(wm831x_rtc);
 297                 if (ret < 0) {
 298                         dev_err(dev, "Failed to start alarm: %d\n", ret);
 299                         return ret;
 300                 }
 301         }
 302
 303         return 0;
 304 }
 305
 306 static int wm831x_rtc_alarm_irq_enable(struct device *dev,
 307                                        unsigned int enabled)
 308 {
 309         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
 310
 311         if (enabled)
 312                 return wm831x_rtc_start_alarm(wm831x_rtc);
 313         else
 314                 return wm831x_rtc_stop_alarm(wm831x_rtc);
 315 }
 316
 317 static int wm831x_rtc_update_irq_enable(struct device *dev,
 318                                         unsigned int enabled)
 319 {
 320         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
 321         int val;
 322
 323         if (enabled)
 324                 val = 1 << WM831X_RTC_PINT_FREQ_SHIFT;
 325         else
 326                 val = 0;
 327
 328         return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
 329                                WM831X_RTC_PINT_FREQ_MASK, val);
 330 }
 331
 332 static irqreturn_t wm831x_alm_irq(int irq, void *data)
 333 {
 334         struct wm831x_rtc *wm831x_rtc = data;
 335
 336         rtc_update_irq(wm831x_rtc->rtc, 1, RTC_IRQF | RTC_AF);
 337
 338         return IRQ_HANDLED;
 339 }
 340
 341 static irqreturn_t wm831x_per_irq(int irq, void *data)
 342 {
 343         struct wm831x_rtc *wm831x_rtc = data;
 344
 345         rtc_update_irq(wm831x_rtc->rtc, 1, RTC_IRQF | RTC_UF);
 346
 347         return IRQ_HANDLED;
 348 }
 349
 350 static const struct rtc_class_ops wm831x_rtc_ops = {
 351         .read_time = wm831x_rtc_readtime,
 352         .set_mmss = wm831x_rtc_set_mmss,
 353         .read_alarm = wm831x_rtc_readalarm,
 354         .set_alarm = wm831x_rtc_setalarm,
 355         .alarm_irq_enable = wm831x_rtc_alarm_irq_enable,
 356         .update_irq_enable = wm831x_rtc_update_irq_enable,
 357 };
 358
 359 #ifdef CONFIG_PM
 360 /* Turn off the alarm if it should not be a wake source. */
 361 static int wm831x_rtc_suspend(struct device *dev)
 362 {
 363         struct platform_device *pdev = to_platform_device(dev);
 364         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
 365         int ret, enable;
 366
 367         if (wm831x_rtc->alarm_enabled && device_may_wakeup(&pdev->dev))
 368                 enable = WM831X_RTC_ALM_ENA;
 369         else
 370                 enable = 0;
 371
 372         ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
 373                               WM831X_RTC_ALM_ENA, enable);
 374         if (ret != 0)
 375                 dev_err(&pdev->dev, "Failed to update RTC alarm: %d\n", ret);
 376
 377         return 0;
 378 }
 379
 380 /* Enable the alarm if it should be enabled (in case it was disabled to
 381  * prevent use as a wake source).
 382  */
 383 static int wm831x_rtc_resume(struct device *dev)
 384 {
 385         struct platform_device *pdev = to_platform_device(dev);
 386         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
 387         int ret;
 388
 389         if (wm831x_rtc->alarm_enabled) {
 390                 ret = wm831x_rtc_start_alarm(wm831x_rtc);
 391                 if (ret != 0)
 392                         dev_err(&pdev->dev,
 393                                 "Failed to restart RTC alarm: %d\n", ret);
 394         }
 395
 396         return 0;
 397 }
 398
 399 /* Unconditionally disable the alarm */
 400 static int wm831x_rtc_freeze(struct device *dev)
 401 {
 402         struct platform_device *pdev = to_platform_device(dev);
 403         struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
 404         int ret;
 405
 406         ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
 407                               WM831X_RTC_ALM_ENA, 0);
 408         if (ret != 0)
 409                 dev_err(&pdev->dev, "Failed to stop RTC alarm: %d\n", ret);
 410
 411         return 0;
 412 }
 413 #else
 414 #define wm831x_rtc_suspend NULL
 415 #define wm831x_rtc_resume NULL
 416 #define wm831x_rtc_freeze NULL
 417 #endif
 418
 419 static int wm831x_rtc_probe(struct platform_device *pdev)
 420 {
 421         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
 422         struct wm831x_rtc *wm831x_rtc;
 423         int per_irq = platform_get_irq_byname(pdev, "PER");
 424         int alm_irq = platform_get_irq_byname(pdev, "ALM");
 425         int ret = 0;
 426
 427         wm831x_rtc = kzalloc(sizeof(*wm831x_rtc), GFP_KERNEL);
 428         if (wm831x_rtc == NULL)
 429                 return -ENOMEM;
 430
 431         platform_set_drvdata(pdev, wm831x_rtc);
 432         wm831x_rtc->wm831x = wm831x;
 433
 434         ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
 435         if (ret < 0) {
 436                 dev_err(&pdev->dev, "Failed to read RTC control: %d\n", ret);
 437                 goto err;
 438         }
 439         if (ret & WM831X_RTC_ALM_ENA)
 440                 wm831x_rtc->alarm_enabled = 1;
 441
 442         device_init_wakeup(&pdev->dev, 1);
 443
 444         wm831x_rtc->rtc = rtc_device_register("wm831x", &pdev->dev,
 445                                               &wm831x_rtc_ops, THIS_MODULE);
 446         if (IS_ERR(wm831x_rtc->rtc)) {
 447                 ret = PTR_ERR(wm831x_rtc->rtc);
 448                 goto err;
 449         }
 450
 451         ret = wm831x_request_irq(wm831x, per_irq, wm831x_per_irq,
 452                                  IRQF_TRIGGER_RISING, "wm831x_rtc_per",
 453                                  wm831x_rtc);
 454         if (ret != 0) {
 455                 dev_err(&pdev->dev, "Failed to request periodic IRQ %d: %d\n",
 456                         per_irq, ret);
 457         }
 458
 459         ret = wm831x_request_irq(wm831x, alm_irq, wm831x_alm_irq,
 460                                  IRQF_TRIGGER_RISING, "wm831x_rtc_alm",
 461                                  wm831x_rtc);
 462         if (ret != 0) {
 463                 dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
 464                         alm_irq, ret);
 465         }
 466
 467         return 0;
 468
 469 err:
 470         kfree(wm831x_rtc);
 471         return ret;
 472 }
 473
 474 static int __devexit wm831x_rtc_remove(struct platform_device *pdev)
 475 {
 476         struct wm831x_rtc *wm831x_rtc = platform_get_drvdata(pdev);
 477         int per_irq = platform_get_irq_byname(pdev, "PER");
 478         int alm_irq = platform_get_irq_byname(pdev, "ALM");
 479
 480         wm831x_free_irq(wm831x_rtc->wm831x, alm_irq, wm831x_rtc);
 481         wm831x_free_irq(wm831x_rtc->wm831x, per_irq, wm831x_rtc);
 482         rtc_device_unregister(wm831x_rtc->rtc);
 483         kfree(wm831x_rtc);
 484
 485         return 0;
 486 }
 487
 488 static const struct dev_pm_ops wm831x_rtc_pm_ops = {
 489         .suspend = wm831x_rtc_suspend,
 490         .resume = wm831x_rtc_resume,
 491
 492         .freeze = wm831x_rtc_freeze,
 493         .thaw = wm831x_rtc_resume,
 494         .restore = wm831x_rtc_resume,
 495
 496         .poweroff = wm831x_rtc_suspend,
 497 };
 498
 499 static struct platform_driver wm831x_rtc_driver = {
 500         .probe = wm831x_rtc_probe,
 501         .remove = __devexit_p(wm831x_rtc_remove),
 502         .driver = {
 503                 .name = "wm831x-rtc",
 504                 .pm = &wm831x_rtc_pm_ops,
 505         },
 506 };
 507
 508 static int __init wm831x_rtc_init(void)
 509 {
 510         return platform_driver_register(&wm831x_rtc_driver);
 511 }
 512 module_init(wm831x_rtc_init);
 513
 514 static void __exit wm831x_rtc_exit(void)
 515 {
 516         platform_driver_unregister(&wm831x_rtc_driver);
 517 }
 518 module_exit(wm831x_rtc_exit);
 519
 520 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 521 MODULE_DESCRIPTION("RTC driver for the WM831x series PMICs");
 522 MODULE_LICENSE("GPL");
 523 MODULE_ALIAS("platform:wm831x-rtc");