drivers/rtc/rtc-wm8350.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      Real Time Clock driver for Wolfson Microelectronics WM8350
   4  *
   5  *      Copyright (C) 2007, 2008 Wolfson Microelectronics PLC.
   6  *
   7  *  Author: Liam Girdwood
   8  *          linux@wolfsonmicro.com
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/kernel.h>
  13 #include <linux/time.h>
  14 #include <linux/rtc.h>
  15 #include <linux/bcd.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/ioctl.h>
  18 #include <linux/completion.h>
  19 #include <linux/mfd/wm8350/rtc.h>
  20 #include <linux/mfd/wm8350/core.h>
  21 #include <linux/delay.h>
  22 #include <linux/platform_device.h>
  23
  24 #define WM8350_SET_ALM_RETRIES  5
  25 #define WM8350_SET_TIME_RETRIES 5
  26 #define WM8350_GET_TIME_RETRIES 5
  27
  28 /*
  29  * Read current time and date in RTC
  30  */
  31 static int wm8350_rtc_readtime(struct device *dev, struct rtc_time *tm)
  32 {
  33         struct wm8350 *wm8350 = dev_get_drvdata(dev);
  34         u16 time1[4], time2[4];
  35         int retries = WM8350_GET_TIME_RETRIES, ret;
  36
  37         /*
  38          * Read the time twice and compare.
  39          * If time1 == time2, then time is valid else retry.
  40          */
  41         do {
  42                 ret = wm8350_block_read(wm8350, WM8350_RTC_SECONDS_MINUTES,
  43                                         4, time1);
  44                 if (ret < 0)
  45                         return ret;
  46                 ret = wm8350_block_read(wm8350, WM8350_RTC_SECONDS_MINUTES,
  47                                         4, time2);
  48                 if (ret < 0)
  49                         return ret;
  50
  51                 if (memcmp(time1, time2, sizeof(time1)) == 0) {
  52                         tm->tm_sec = time1[0] & WM8350_RTC_SECS_MASK;
  53
  54                         tm->tm_min = (time1[0] & WM8350_RTC_MINS_MASK)
  55                             >> WM8350_RTC_MINS_SHIFT;
  56
  57                         tm->tm_hour = time1[1] & WM8350_RTC_HRS_MASK;
  58
  59                         tm->tm_wday = ((time1[1] >> WM8350_RTC_DAY_SHIFT)
  60                                        & 0x7) - 1;
  61
  62                         tm->tm_mon = ((time1[2] & WM8350_RTC_MTH_MASK)
  63                                       >> WM8350_RTC_MTH_SHIFT) - 1;
  64
  65                         tm->tm_mday = (time1[2] & WM8350_RTC_DATE_MASK);
  66
  67                         tm->tm_year = ((time1[3] & WM8350_RTC_YHUNDREDS_MASK)
  68                                        >> WM8350_RTC_YHUNDREDS_SHIFT) * 100;
  69                         tm->tm_year += time1[3] & WM8350_RTC_YUNITS_MASK;
  70
  71                         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon,
  72                                                     tm->tm_year);
  73                         tm->tm_year -= 1900;
  74
  75                         dev_dbg(dev, "Read (%d left): %04x %04x %04x %04x\n",
  76                                 retries,
  77                                 time1[0], time1[1], time1[2], time1[3]);
  78
  79                         return 0;
  80                 }
  81         } while (retries--);
  82
  83         dev_err(dev, "timed out reading RTC time\n");
  84         return -EIO;
  85 }
  86
  87 /*
  88  * Set current time and date in RTC
  89  */
  90 static int wm8350_rtc_settime(struct device *dev, struct rtc_time *tm)
  91 {
  92         struct wm8350 *wm8350 = dev_get_drvdata(dev);
  93         u16 time[4];
  94         u16 rtc_ctrl;
  95         int ret, retries = WM8350_SET_TIME_RETRIES;
  96
  97         time[0] = tm->tm_sec;
  98         time[0] |= tm->tm_min << WM8350_RTC_MINS_SHIFT;
  99         time[1] = tm->tm_hour;
 100         time[1] |= (tm->tm_wday + 1) << WM8350_RTC_DAY_SHIFT;
 101         time[2] = tm->tm_mday;
 102         time[2] |= (tm->tm_mon + 1) << WM8350_RTC_MTH_SHIFT;
 103         time[3] = ((tm->tm_year + 1900) / 100) << WM8350_RTC_YHUNDREDS_SHIFT;
 104         time[3] |= (tm->tm_year + 1900) % 100;
 105
 106         dev_dbg(dev, "Setting: %04x %04x %04x %04x\n",
 107                 time[0], time[1], time[2], time[3]);
 108
 109         /* Set RTC_SET to stop the clock */
 110         ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL, WM8350_RTC_SET);
 111         if (ret < 0)
 112                 return ret;
 113
 114         /* Wait until confirmation of stopping */
 115         do {
 116                 rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
 117                 schedule_timeout_uninterruptible(msecs_to_jiffies(1));
 118         } while (--retries && !(rtc_ctrl & WM8350_RTC_STS));
 119
 120         if (!retries) {
 121                 dev_err(dev, "timed out on set confirmation\n");
 122                 return -EIO;
 123         }
 124
 125         /* Write time to RTC */
 126         ret = wm8350_block_write(wm8350, WM8350_RTC_SECONDS_MINUTES, 4, time);
 127         if (ret < 0)
 128                 return ret;
 129
 130         /* Clear RTC_SET to start the clock */
 131         ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
 132                                 WM8350_RTC_SET);
 133         return ret;
 134 }
 135
 136 /*
 137  * Read alarm time and date in RTC
 138  */
 139 static int wm8350_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 140 {
 141         struct wm8350 *wm8350 = dev_get_drvdata(dev);
 142         struct rtc_time *tm = &alrm->time;
 143         u16 time[4];
 144         int ret;
 145
 146         ret = wm8350_block_read(wm8350, WM8350_ALARM_SECONDS_MINUTES, 4, time);
 147         if (ret < 0)
 148                 return ret;
 149
 150         tm->tm_sec = time[0] & WM8350_RTC_ALMSECS_MASK;
 151         if (tm->tm_sec == WM8350_RTC_ALMSECS_MASK)
 152                 tm->tm_sec = -1;
 153
 154         tm->tm_min = time[0] & WM8350_RTC_ALMMINS_MASK;
 155         if (tm->tm_min == WM8350_RTC_ALMMINS_MASK)
 156                 tm->tm_min = -1;
 157         else
 158                 tm->tm_min >>= WM8350_RTC_ALMMINS_SHIFT;
 159
 160         tm->tm_hour = time[1] & WM8350_RTC_ALMHRS_MASK;
 161         if (tm->tm_hour == WM8350_RTC_ALMHRS_MASK)
 162                 tm->tm_hour = -1;
 163
 164         tm->tm_wday = ((time[1] >> WM8350_RTC_ALMDAY_SHIFT) & 0x7) - 1;
 165         if (tm->tm_wday > 7)
 166                 tm->tm_wday = -1;
 167
 168         tm->tm_mon = time[2] & WM8350_RTC_ALMMTH_MASK;
 169         if (tm->tm_mon == WM8350_RTC_ALMMTH_MASK)
 170                 tm->tm_mon = -1;
 171         else
 172                 tm->tm_mon = (tm->tm_mon >> WM8350_RTC_ALMMTH_SHIFT) - 1;
 173
 174         tm->tm_mday = (time[2] & WM8350_RTC_ALMDATE_MASK);
 175         if (tm->tm_mday == WM8350_RTC_ALMDATE_MASK)
 176                 tm->tm_mday = -1;
 177
 178         tm->tm_year = -1;
 179
 180         alrm->enabled = !(time[3] & WM8350_RTC_ALMSTS);
 181
 182         return 0;
 183 }
 184
 185 static int wm8350_rtc_stop_alarm(struct wm8350 *wm8350)
 186 {
 187         int retries = WM8350_SET_ALM_RETRIES;
 188         u16 rtc_ctrl;
 189         int ret;
 190
 191         /* Set RTC_SET to stop the clock */
 192         ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL,
 193                               WM8350_RTC_ALMSET);
 194         if (ret < 0)
 195                 return ret;
 196
 197         /* Wait until confirmation of stopping */
 198         do {
 199                 rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
 200                 schedule_timeout_uninterruptible(msecs_to_jiffies(1));
 201         } while (retries-- && !(rtc_ctrl & WM8350_RTC_ALMSTS));
 202
 203         if (!(rtc_ctrl & WM8350_RTC_ALMSTS))
 204                 return -ETIMEDOUT;
 205
 206         return 0;
 207 }
 208
 209 static int wm8350_rtc_start_alarm(struct wm8350 *wm8350)
 210 {
 211         int ret;
 212         int retries = WM8350_SET_ALM_RETRIES;
 213         u16 rtc_ctrl;
 214
 215         ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
 216                                 WM8350_RTC_ALMSET);
 217         if (ret < 0)
 218                 return ret;
 219
 220         /* Wait until confirmation */
 221         do {
 222                 rtc_ctrl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
 223                 schedule_timeout_uninterruptible(msecs_to_jiffies(1));
 224         } while (retries-- && rtc_ctrl & WM8350_RTC_ALMSTS);
 225
 226         if (rtc_ctrl & WM8350_RTC_ALMSTS)
 227                 return -ETIMEDOUT;
 228
 229         return 0;
 230 }
 231
 232 static int wm8350_rtc_alarm_irq_enable(struct device *dev,
 233                                        unsigned int enabled)
 234 {
 235         struct wm8350 *wm8350 = dev_get_drvdata(dev);
 236
 237         if (enabled)
 238                 return wm8350_rtc_start_alarm(wm8350);
 239         else
 240                 return wm8350_rtc_stop_alarm(wm8350);
 241 }
 242
 243 static int wm8350_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 244 {
 245         struct wm8350 *wm8350 = dev_get_drvdata(dev);
 246         struct rtc_time *tm = &alrm->time;
 247         u16 time[3];
 248         int ret;
 249
 250         memset(time, 0, sizeof(time));
 251
 252         if (tm->tm_sec != -1)
 253                 time[0] |= tm->tm_sec;
 254         else
 255                 time[0] |= WM8350_RTC_ALMSECS_MASK;
 256
 257         if (tm->tm_min != -1)
 258                 time[0] |= tm->tm_min << WM8350_RTC_ALMMINS_SHIFT;
 259         else
 260                 time[0] |= WM8350_RTC_ALMMINS_MASK;
 261
 262         if (tm->tm_hour != -1)
 263                 time[1] |= tm->tm_hour;
 264         else
 265                 time[1] |= WM8350_RTC_ALMHRS_MASK;
 266
 267         if (tm->tm_wday != -1)
 268                 time[1] |= (tm->tm_wday + 1) << WM8350_RTC_ALMDAY_SHIFT;
 269         else
 270                 time[1] |= WM8350_RTC_ALMDAY_MASK;
 271
 272         if (tm->tm_mday != -1)
 273                 time[2] |= tm->tm_mday;
 274         else
 275                 time[2] |= WM8350_RTC_ALMDATE_MASK;
 276
 277         if (tm->tm_mon != -1)
 278                 time[2] |= (tm->tm_mon + 1) << WM8350_RTC_ALMMTH_SHIFT;
 279         else
 280                 time[2] |= WM8350_RTC_ALMMTH_MASK;
 281
 282         ret = wm8350_rtc_stop_alarm(wm8350);
 283         if (ret < 0)
 284                 return ret;
 285
 286         /* Write time to RTC */
 287         ret = wm8350_block_write(wm8350, WM8350_ALARM_SECONDS_MINUTES,
 288                                  3, time);
 289         if (ret < 0)
 290                 return ret;
 291
 292         if (alrm->enabled)
 293                 ret = wm8350_rtc_start_alarm(wm8350);
 294
 295         return ret;
 296 }
 297
 298 static irqreturn_t wm8350_rtc_alarm_handler(int irq, void *data)
 299 {
 300         struct wm8350 *wm8350 = data;
 301         struct rtc_device *rtc = wm8350->rtc.rtc;
 302         int ret;
 303
 304         rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
 305
 306         /* Make it one shot */
 307         ret = wm8350_set_bits(wm8350, WM8350_RTC_TIME_CONTROL,
 308                               WM8350_RTC_ALMSET);
 309         if (ret != 0) {
 310                 dev_err(&(wm8350->rtc.pdev->dev),
 311                         "Failed to disable alarm: %d\n", ret);
 312         }
 313
 314         return IRQ_HANDLED;
 315 }
 316
 317 static irqreturn_t wm8350_rtc_update_handler(int irq, void *data)
 318 {
 319         struct wm8350 *wm8350 = data;
 320         struct rtc_device *rtc = wm8350->rtc.rtc;
 321
 322         rtc_update_irq(rtc, 1, RTC_IRQF | RTC_UF);
 323
 324         return IRQ_HANDLED;
 325 }
 326
 327 static const struct rtc_class_ops wm8350_rtc_ops = {
 328         .read_time = wm8350_rtc_readtime,
 329         .set_time = wm8350_rtc_settime,
 330         .read_alarm = wm8350_rtc_readalarm,
 331         .set_alarm = wm8350_rtc_setalarm,
 332         .alarm_irq_enable = wm8350_rtc_alarm_irq_enable,
 333 };
 334
 335 #ifdef CONFIG_PM_SLEEP
 336 static int wm8350_rtc_suspend(struct device *dev)
 337 {
 338         struct wm8350 *wm8350 = dev_get_drvdata(dev);
 339         int ret = 0;
 340         u16 reg;
 341
 342         reg = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
 343
 344         if (device_may_wakeup(&wm8350->rtc.pdev->dev) &&
 345             reg & WM8350_RTC_ALMSTS) {
 346                 ret = wm8350_rtc_stop_alarm(wm8350);
 347                 if (ret != 0)
 348                         dev_err(dev, "Failed to stop RTC alarm: %d\n", ret);
 349         }
 350
 351         return ret;
 352 }
 353
 354 static int wm8350_rtc_resume(struct device *dev)
 355 {
 356         struct wm8350 *wm8350 = dev_get_drvdata(dev);
 357         int ret;
 358
 359         if (wm8350->rtc.alarm_enabled) {
 360                 ret = wm8350_rtc_start_alarm(wm8350);
 361                 if (ret != 0)
 362                         dev_err(dev, "Failed to restart RTC alarm: %d\n", ret);
 363         }
 364
 365         return 0;
 366 }
 367 #endif
 368
 369 static int wm8350_rtc_probe(struct platform_device *pdev)
 370 {
 371         struct wm8350 *wm8350 = platform_get_drvdata(pdev);
 372         struct wm8350_rtc *wm_rtc = &wm8350->rtc;
 373         int ret = 0;
 374         u16 timectl, power5;
 375
 376         timectl = wm8350_reg_read(wm8350, WM8350_RTC_TIME_CONTROL);
 377         if (timectl & WM8350_RTC_BCD) {
 378                 dev_err(&pdev->dev, "RTC BCD mode not supported\n");
 379                 return -EINVAL;
 380         }
 381         if (timectl & WM8350_RTC_12HR) {
 382                 dev_err(&pdev->dev, "RTC 12 hour mode not supported\n");
 383                 return -EINVAL;
 384         }
 385
 386         /* enable the RTC if it's not already enabled */
 387         power5 = wm8350_reg_read(wm8350, WM8350_POWER_MGMT_5);
 388         if (!(power5 &  WM8350_RTC_TICK_ENA)) {
 389                 dev_info(wm8350->dev, "Starting RTC\n");
 390
 391                 wm8350_reg_unlock(wm8350);
 392
 393                 ret = wm8350_set_bits(wm8350, WM8350_POWER_MGMT_5,
 394                                       WM8350_RTC_TICK_ENA);
 395                 if (ret < 0) {
 396                         dev_err(&pdev->dev, "failed to enable RTC: %d\n", ret);
 397                         return ret;
 398                 }
 399
 400                 wm8350_reg_lock(wm8350);
 401         }
 402
 403         if (timectl & WM8350_RTC_STS) {
 404                 int retries;
 405
 406                 ret = wm8350_clear_bits(wm8350, WM8350_RTC_TIME_CONTROL,
 407                                         WM8350_RTC_SET);
 408                 if (ret < 0) {
 409                         dev_err(&pdev->dev, "failed to start: %d\n", ret);
 410                         return ret;
 411                 }
 412
 413                 retries = WM8350_SET_TIME_RETRIES;
 414                 do {
 415                         timectl = wm8350_reg_read(wm8350,
 416                                                   WM8350_RTC_TIME_CONTROL);
 417                 } while (timectl & WM8350_RTC_STS && --retries);
 418
 419                 if (retries == 0) {
 420                         dev_err(&pdev->dev, "failed to start: timeout\n");
 421                         return -ENODEV;
 422                 }
 423         }
 424
 425         device_init_wakeup(&pdev->dev, 1);
 426
 427         wm_rtc->rtc = devm_rtc_device_register(&pdev->dev, "wm8350",
 428                                         &wm8350_rtc_ops, THIS_MODULE);
 429         if (IS_ERR(wm_rtc->rtc)) {
 430                 ret = PTR_ERR(wm_rtc->rtc);
 431                 dev_err(&pdev->dev, "failed to register RTC: %d\n", ret);
 432                 return ret;
 433         }
 434
 435         wm8350_register_irq(wm8350, WM8350_IRQ_RTC_SEC,
 436                             wm8350_rtc_update_handler, 0,
 437                             "RTC Seconds", wm8350);
 438         wm8350_mask_irq(wm8350, WM8350_IRQ_RTC_SEC);
 439
 440         wm8350_register_irq(wm8350, WM8350_IRQ_RTC_ALM,
 441                             wm8350_rtc_alarm_handler, 0,
 442                             "RTC Alarm", wm8350);
 443
 444         return 0;
 445 }
 446
 447 static int wm8350_rtc_remove(struct platform_device *pdev)
 448 {
 449         struct wm8350 *wm8350 = platform_get_drvdata(pdev);
 450
 451         wm8350_free_irq(wm8350, WM8350_IRQ_RTC_SEC, wm8350);
 452         wm8350_free_irq(wm8350, WM8350_IRQ_RTC_ALM, wm8350);
 453
 454         return 0;
 455 }
 456
 457 static SIMPLE_DEV_PM_OPS(wm8350_rtc_pm_ops, wm8350_rtc_suspend,
 458                         wm8350_rtc_resume);
 459
 460 static struct platform_driver wm8350_rtc_driver = {
 461         .probe = wm8350_rtc_probe,
 462         .remove = wm8350_rtc_remove,
 463         .driver = {
 464                 .name = "wm8350-rtc",
 465                 .pm = &wm8350_rtc_pm_ops,
 466         },
 467 };
 468
 469 module_platform_driver(wm8350_rtc_driver);
 470
 471 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 472 MODULE_DESCRIPTION("RTC driver for the WM8350");
 473 MODULE_LICENSE("GPL");
 474 MODULE_ALIAS("platform:wm8350-rtc");