linux/drivers/rtc/rtc-wm8350.c
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   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 */
  31static 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 */
  90static 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 */
 139static 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
 185static 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
 209static 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
 232static 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
 243static 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
 298static 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
 317static 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
 327static 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
 336static 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
 354static 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
 369static 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
 447static 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
 457static SIMPLE_DEV_PM_OPS(wm8350_rtc_pm_ops, wm8350_rtc_suspend,
 458                        wm8350_rtc_resume);
 459
 460static 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
 469module_platform_driver(wm8350_rtc_driver);
 470
 471MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 472MODULE_DESCRIPTION("RTC driver for the WM8350");
 473MODULE_LICENSE("GPL");
 474MODULE_ALIAS("platform:wm8350-rtc");
 475