linux/drivers/rtc/rtc-bd70528.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2//
   3// Copyright (C) 2018 ROHM Semiconductors
   4//
   5// RTC driver for ROHM BD70528 PMIC
   6
   7#include <linux/bcd.h>
   8#include <linux/mfd/rohm-bd70528.h>
   9#include <linux/module.h>
  10#include <linux/of.h>
  11#include <linux/platform_device.h>
  12#include <linux/regmap.h>
  13#include <linux/rtc.h>
  14
  15/*
  16 * We read regs RTC_SEC => RTC_YEAR
  17 * this struct is ordered according to chip registers.
  18 * Keep it u8 only to avoid padding issues.
  19 */
  20struct bd70528_rtc_day {
  21        u8 sec;
  22        u8 min;
  23        u8 hour;
  24} __packed;
  25
  26struct bd70528_rtc_data {
  27        struct bd70528_rtc_day time;
  28        u8 week;
  29        u8 day;
  30        u8 month;
  31        u8 year;
  32} __packed;
  33
  34struct bd70528_rtc_wake {
  35        struct bd70528_rtc_day time;
  36        u8 ctrl;
  37} __packed;
  38
  39struct bd70528_rtc_alm {
  40        struct bd70528_rtc_data data;
  41        u8 alm_mask;
  42        u8 alm_repeat;
  43} __packed;
  44
  45struct bd70528_rtc {
  46        struct rohm_regmap_dev *mfd;
  47        struct device *dev;
  48};
  49
  50static int bd70528_set_wake(struct rohm_regmap_dev *bd70528,
  51                            int enable, int *old_state)
  52{
  53        int ret;
  54        unsigned int ctrl_reg;
  55
  56        ret = regmap_read(bd70528->regmap, BD70528_REG_WAKE_EN, &ctrl_reg);
  57        if (ret)
  58                return ret;
  59
  60        if (old_state) {
  61                if (ctrl_reg & BD70528_MASK_WAKE_EN)
  62                        *old_state |= BD70528_WAKE_STATE_BIT;
  63                else
  64                        *old_state &= ~BD70528_WAKE_STATE_BIT;
  65
  66                if (!enable == !(*old_state & BD70528_WAKE_STATE_BIT))
  67                        return 0;
  68        }
  69
  70        if (enable)
  71                ctrl_reg |= BD70528_MASK_WAKE_EN;
  72        else
  73                ctrl_reg &= ~BD70528_MASK_WAKE_EN;
  74
  75        return regmap_write(bd70528->regmap, BD70528_REG_WAKE_EN,
  76                            ctrl_reg);
  77}
  78
  79static int bd70528_set_elapsed_tmr(struct rohm_regmap_dev *bd70528,
  80                                   int enable, int *old_state)
  81{
  82        int ret;
  83        unsigned int ctrl_reg;
  84
  85        /*
  86         * TBD
  87         * What is the purpose of elapsed timer ?
  88         * Is the timeout registers counting down, or is the disable - re-enable
  89         * going to restart the elapsed-time counting? If counting is restarted
  90         * the timeout should be decreased by the amount of time that has
  91         * elapsed since starting the timer. Maybe we should store the monotonic
  92         * clock value when timer is started so that if RTC is set while timer
  93         * is armed we could do the compensation. This is a hack if RTC/system
  94         * clk are drifting. OTOH, RTC controlled via I2C is in any case
  95         * inaccurate...
  96         */
  97        ret = regmap_read(bd70528->regmap, BD70528_REG_ELAPSED_TIMER_EN,
  98                          &ctrl_reg);
  99        if (ret)
 100                return ret;
 101
 102        if (old_state) {
 103                if (ctrl_reg & BD70528_MASK_ELAPSED_TIMER_EN)
 104                        *old_state |= BD70528_ELAPSED_STATE_BIT;
 105                else
 106                        *old_state &= ~BD70528_ELAPSED_STATE_BIT;
 107
 108                if ((!enable) == (!(*old_state & BD70528_ELAPSED_STATE_BIT)))
 109                        return 0;
 110        }
 111
 112        if (enable)
 113                ctrl_reg |= BD70528_MASK_ELAPSED_TIMER_EN;
 114        else
 115                ctrl_reg &= ~BD70528_MASK_ELAPSED_TIMER_EN;
 116
 117        return regmap_write(bd70528->regmap, BD70528_REG_ELAPSED_TIMER_EN,
 118                            ctrl_reg);
 119}
 120
 121static int bd70528_set_rtc_based_timers(struct bd70528_rtc *r, int new_state,
 122                                        int *old_state)
 123{
 124        int ret;
 125
 126        ret = bd70528_wdt_set(r->mfd, new_state & BD70528_WDT_STATE_BIT,
 127                              old_state);
 128        if (ret) {
 129                dev_err(r->dev,
 130                        "Failed to disable WDG for RTC setting (%d)\n", ret);
 131                return ret;
 132        }
 133        ret = bd70528_set_elapsed_tmr(r->mfd,
 134                                      new_state & BD70528_ELAPSED_STATE_BIT,
 135                                      old_state);
 136        if (ret) {
 137                dev_err(r->dev,
 138                        "Failed to disable 'elapsed timer' for RTC setting\n");
 139                return ret;
 140        }
 141        ret = bd70528_set_wake(r->mfd, new_state & BD70528_WAKE_STATE_BIT,
 142                               old_state);
 143        if (ret) {
 144                dev_err(r->dev,
 145                        "Failed to disable 'wake timer' for RTC setting\n");
 146                return ret;
 147        }
 148
 149        return ret;
 150}
 151
 152static int bd70528_re_enable_rtc_based_timers(struct bd70528_rtc *r,
 153                                              int old_state)
 154{
 155        return bd70528_set_rtc_based_timers(r, old_state, NULL);
 156}
 157
 158static int bd70528_disable_rtc_based_timers(struct bd70528_rtc *r,
 159                                            int *old_state)
 160{
 161        return bd70528_set_rtc_based_timers(r, 0, old_state);
 162}
 163
 164static inline void tmday2rtc(struct rtc_time *t, struct bd70528_rtc_day *d)
 165{
 166        d->sec &= ~BD70528_MASK_RTC_SEC;
 167        d->min &= ~BD70528_MASK_RTC_MINUTE;
 168        d->hour &= ~BD70528_MASK_RTC_HOUR;
 169        d->sec |= bin2bcd(t->tm_sec);
 170        d->min |= bin2bcd(t->tm_min);
 171        d->hour |= bin2bcd(t->tm_hour);
 172}
 173
 174static inline void tm2rtc(struct rtc_time *t, struct bd70528_rtc_data *r)
 175{
 176        r->day &= ~BD70528_MASK_RTC_DAY;
 177        r->week &= ~BD70528_MASK_RTC_WEEK;
 178        r->month &= ~BD70528_MASK_RTC_MONTH;
 179        /*
 180         * PM and 24H bits are not used by Wake - thus we clear them
 181         * here and not in tmday2rtc() which is also used by wake.
 182         */
 183        r->time.hour &= ~(BD70528_MASK_RTC_HOUR_PM | BD70528_MASK_RTC_HOUR_24H);
 184
 185        tmday2rtc(t, &r->time);
 186        /*
 187         * We do always set time in 24H mode.
 188         */
 189        r->time.hour |= BD70528_MASK_RTC_HOUR_24H;
 190        r->day |= bin2bcd(t->tm_mday);
 191        r->week |= bin2bcd(t->tm_wday);
 192        r->month |= bin2bcd(t->tm_mon + 1);
 193        r->year = bin2bcd(t->tm_year - 100);
 194}
 195
 196static inline void rtc2tm(struct bd70528_rtc_data *r, struct rtc_time *t)
 197{
 198        t->tm_sec = bcd2bin(r->time.sec & BD70528_MASK_RTC_SEC);
 199        t->tm_min = bcd2bin(r->time.min & BD70528_MASK_RTC_MINUTE);
 200        t->tm_hour = bcd2bin(r->time.hour & BD70528_MASK_RTC_HOUR);
 201        /*
 202         * If RTC is in 12H mode, then bit BD70528_MASK_RTC_HOUR_PM
 203         * is not BCD value but tells whether it is AM or PM
 204         */
 205        if (!(r->time.hour & BD70528_MASK_RTC_HOUR_24H)) {
 206                t->tm_hour %= 12;
 207                if (r->time.hour & BD70528_MASK_RTC_HOUR_PM)
 208                        t->tm_hour += 12;
 209        }
 210        t->tm_mday = bcd2bin(r->day & BD70528_MASK_RTC_DAY);
 211        t->tm_mon = bcd2bin(r->month & BD70528_MASK_RTC_MONTH) - 1;
 212        t->tm_year = 100 + bcd2bin(r->year & BD70528_MASK_RTC_YEAR);
 213        t->tm_wday = bcd2bin(r->week & BD70528_MASK_RTC_WEEK);
 214}
 215
 216static int bd70528_set_alarm(struct device *dev, struct rtc_wkalrm *a)
 217{
 218        struct bd70528_rtc_wake wake;
 219        struct bd70528_rtc_alm alm;
 220        int ret;
 221        struct bd70528_rtc *r = dev_get_drvdata(dev);
 222        struct rohm_regmap_dev *bd70528 = r->mfd;
 223
 224        ret = regmap_bulk_read(bd70528->regmap, BD70528_REG_RTC_WAKE_START,
 225                               &wake, sizeof(wake));
 226        if (ret) {
 227                dev_err(dev, "Failed to read wake regs\n");
 228                return ret;
 229        }
 230
 231        ret = regmap_bulk_read(bd70528->regmap, BD70528_REG_RTC_ALM_START,
 232                               &alm, sizeof(alm));
 233        if (ret) {
 234                dev_err(dev, "Failed to read alarm regs\n");
 235                return ret;
 236        }
 237
 238        tm2rtc(&a->time, &alm.data);
 239        tmday2rtc(&a->time, &wake.time);
 240
 241        if (a->enabled) {
 242                alm.alm_mask &= ~BD70528_MASK_ALM_EN;
 243                wake.ctrl |= BD70528_MASK_WAKE_EN;
 244        } else {
 245                alm.alm_mask |= BD70528_MASK_ALM_EN;
 246                wake.ctrl &= ~BD70528_MASK_WAKE_EN;
 247        }
 248
 249        ret = regmap_bulk_write(bd70528->regmap,
 250                                BD70528_REG_RTC_WAKE_START, &wake,
 251                                sizeof(wake));
 252        if (ret) {
 253                dev_err(dev, "Failed to set wake time\n");
 254                return ret;
 255        }
 256        ret = regmap_bulk_write(bd70528->regmap, BD70528_REG_RTC_ALM_START,
 257                                &alm, sizeof(alm));
 258        if (ret)
 259                dev_err(dev, "Failed to set alarm time\n");
 260
 261        return ret;
 262}
 263
 264static int bd70528_read_alarm(struct device *dev, struct rtc_wkalrm *a)
 265{
 266        struct bd70528_rtc_alm alm;
 267        int ret;
 268        struct bd70528_rtc *r = dev_get_drvdata(dev);
 269        struct rohm_regmap_dev *bd70528 = r->mfd;
 270
 271        ret = regmap_bulk_read(bd70528->regmap, BD70528_REG_RTC_ALM_START,
 272                               &alm, sizeof(alm));
 273        if (ret) {
 274                dev_err(dev, "Failed to read alarm regs\n");
 275                return ret;
 276        }
 277
 278        rtc2tm(&alm.data, &a->time);
 279        a->time.tm_mday = -1;
 280        a->time.tm_mon = -1;
 281        a->time.tm_year = -1;
 282        a->enabled = !(alm.alm_mask & BD70528_MASK_ALM_EN);
 283        a->pending = 0;
 284
 285        return 0;
 286}
 287
 288static int bd70528_set_time_locked(struct device *dev, struct rtc_time *t)
 289{
 290        int ret, tmpret, old_states;
 291        struct bd70528_rtc_data rtc_data;
 292        struct bd70528_rtc *r = dev_get_drvdata(dev);
 293        struct rohm_regmap_dev *bd70528 = r->mfd;
 294
 295        ret = bd70528_disable_rtc_based_timers(r, &old_states);
 296        if (ret)
 297                return ret;
 298
 299        tmpret = regmap_bulk_read(bd70528->regmap,
 300                                  BD70528_REG_RTC_START, &rtc_data,
 301                                  sizeof(rtc_data));
 302        if (tmpret) {
 303                dev_err(dev, "Failed to read RTC time registers\n");
 304                goto renable_out;
 305        }
 306        tm2rtc(t, &rtc_data);
 307
 308        tmpret = regmap_bulk_write(bd70528->regmap,
 309                                   BD70528_REG_RTC_START, &rtc_data,
 310                                   sizeof(rtc_data));
 311        if (tmpret) {
 312                dev_err(dev, "Failed to set RTC time\n");
 313                goto renable_out;
 314        }
 315
 316renable_out:
 317        ret = bd70528_re_enable_rtc_based_timers(r, old_states);
 318        if (tmpret)
 319                ret = tmpret;
 320
 321        return ret;
 322}
 323
 324static int bd70528_set_time(struct device *dev, struct rtc_time *t)
 325{
 326        int ret;
 327        struct bd70528_rtc *r = dev_get_drvdata(dev);
 328
 329        bd70528_wdt_lock(r->mfd);
 330        ret = bd70528_set_time_locked(dev, t);
 331        bd70528_wdt_unlock(r->mfd);
 332        return ret;
 333}
 334
 335static int bd70528_get_time(struct device *dev, struct rtc_time *t)
 336{
 337        struct bd70528_rtc *r = dev_get_drvdata(dev);
 338        struct rohm_regmap_dev *bd70528 = r->mfd;
 339        struct bd70528_rtc_data rtc_data;
 340        int ret;
 341
 342        /* read the RTC date and time registers all at once */
 343        ret = regmap_bulk_read(bd70528->regmap,
 344                               BD70528_REG_RTC_START, &rtc_data,
 345                               sizeof(rtc_data));
 346        if (ret) {
 347                dev_err(dev, "Failed to read RTC time (err %d)\n", ret);
 348                return ret;
 349        }
 350
 351        rtc2tm(&rtc_data, t);
 352
 353        return 0;
 354}
 355
 356static int bd70528_alm_enable(struct device *dev, unsigned int enabled)
 357{
 358        int ret;
 359        unsigned int enableval = BD70528_MASK_ALM_EN;
 360        struct bd70528_rtc *r = dev_get_drvdata(dev);
 361
 362        if (enabled)
 363                enableval = 0;
 364
 365        bd70528_wdt_lock(r->mfd);
 366        ret = bd70528_set_wake(r->mfd, enabled, NULL);
 367        if (ret) {
 368                dev_err(dev, "Failed to change wake state\n");
 369                goto out_unlock;
 370        }
 371        ret = regmap_update_bits(r->mfd->regmap, BD70528_REG_RTC_ALM_MASK,
 372                                 BD70528_MASK_ALM_EN, enableval);
 373        if (ret)
 374                dev_err(dev, "Failed to change alarm state\n");
 375
 376out_unlock:
 377        bd70528_wdt_unlock(r->mfd);
 378        return ret;
 379}
 380
 381static const struct rtc_class_ops bd70528_rtc_ops = {
 382        .read_time              = bd70528_get_time,
 383        .set_time               = bd70528_set_time,
 384        .read_alarm             = bd70528_read_alarm,
 385        .set_alarm              = bd70528_set_alarm,
 386        .alarm_irq_enable       = bd70528_alm_enable,
 387};
 388
 389static irqreturn_t alm_hndlr(int irq, void *data)
 390{
 391        struct rtc_device *rtc = data;
 392
 393        rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF | RTC_PF);
 394        return IRQ_HANDLED;
 395}
 396
 397static int bd70528_probe(struct platform_device *pdev)
 398{
 399        struct bd70528_rtc *bd_rtc;
 400        struct rohm_regmap_dev *mfd;
 401        int ret;
 402        struct rtc_device *rtc;
 403        int irq;
 404        unsigned int hr;
 405
 406        mfd = dev_get_drvdata(pdev->dev.parent);
 407        if (!mfd) {
 408                dev_err(&pdev->dev, "No MFD driver data\n");
 409                return -EINVAL;
 410        }
 411        bd_rtc = devm_kzalloc(&pdev->dev, sizeof(*bd_rtc), GFP_KERNEL);
 412        if (!bd_rtc)
 413                return -ENOMEM;
 414
 415        bd_rtc->mfd = mfd;
 416        bd_rtc->dev = &pdev->dev;
 417
 418        irq = platform_get_irq_byname(pdev, "bd70528-rtc-alm");
 419        if (irq < 0)
 420                return irq;
 421
 422        platform_set_drvdata(pdev, bd_rtc);
 423
 424        ret = regmap_read(mfd->regmap, BD70528_REG_RTC_HOUR, &hr);
 425
 426        if (ret) {
 427                dev_err(&pdev->dev, "Failed to reag RTC clock\n");
 428                return ret;
 429        }
 430
 431        if (!(hr & BD70528_MASK_RTC_HOUR_24H)) {
 432                struct rtc_time t;
 433
 434                ret = bd70528_get_time(&pdev->dev, &t);
 435
 436                if (!ret)
 437                        ret = bd70528_set_time(&pdev->dev, &t);
 438
 439                if (ret) {
 440                        dev_err(&pdev->dev,
 441                                "Setting 24H clock for RTC failed\n");
 442                        return ret;
 443                }
 444        }
 445
 446        device_set_wakeup_capable(&pdev->dev, true);
 447        device_wakeup_enable(&pdev->dev);
 448
 449        rtc = devm_rtc_allocate_device(&pdev->dev);
 450        if (IS_ERR(rtc)) {
 451                dev_err(&pdev->dev, "RTC device creation failed\n");
 452                return PTR_ERR(rtc);
 453        }
 454
 455        rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 456        rtc->range_max = RTC_TIMESTAMP_END_2099;
 457        rtc->ops = &bd70528_rtc_ops;
 458
 459        /* Request alarm IRQ prior to registerig the RTC */
 460        ret = devm_request_threaded_irq(&pdev->dev, irq, NULL, &alm_hndlr,
 461                                        IRQF_ONESHOT, "bd70528-rtc", rtc);
 462        if (ret)
 463                return ret;
 464
 465        /*
 466         *  BD70528 irq controller is not touching the main mask register.
 467         *  So enable the RTC block interrupts at main level. We can just
 468         *  leave them enabled as irq-controller should disable irqs
 469         *  from sub-registers when IRQ is disabled or freed.
 470         */
 471        ret = regmap_update_bits(mfd->regmap,
 472                                 BD70528_REG_INT_MAIN_MASK,
 473                                 BD70528_INT_RTC_MASK, 0);
 474        if (ret) {
 475                dev_err(&pdev->dev, "Failed to enable RTC interrupts\n");
 476                return ret;
 477        }
 478
 479        return rtc_register_device(rtc);
 480}
 481
 482static struct platform_driver bd70528_rtc = {
 483        .driver = {
 484                .name = "bd70528-rtc"
 485        },
 486        .probe = bd70528_probe,
 487};
 488
 489module_platform_driver(bd70528_rtc);
 490
 491MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
 492MODULE_DESCRIPTION("BD70528 RTC driver");
 493MODULE_LICENSE("GPL");
 494