LXR linux/drivers/rtc/rtc-rk808.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * RTC driver for Rockchip RK808
   4 *
   5 * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
   6 *
   7 * Author: Chris Zhong <zyw@rock-chips.com>
   8 * Author: Zhang Qing <zhangqing@rock-chips.com>
   9 */
  10
  11#include <linux/module.h>
  12#include <linux/kernel.h>
  13#include <linux/rtc.h>
  14#include <linux/bcd.h>
  15#include <linux/mfd/rk808.h>
  16#include <linux/platform_device.h>
  17#include <linux/i2c.h>
  18
  19/* RTC_CTRL_REG bitfields */
  20#define BIT_RTC_CTRL_REG_STOP_RTC_M             BIT(0)
  21
  22/* RK808 has a shadowed register for saving a "frozen" RTC time.
  23 * When user setting "GET_TIME" to 1, the time will save in this shadowed
  24 * register. If set "READSEL" to 1, user read rtc time register, actually
  25 * get the time of that moment. If we need the real time, clr this bit.
  26 */
  27#define BIT_RTC_CTRL_REG_RTC_GET_TIME           BIT(6)
  28#define BIT_RTC_CTRL_REG_RTC_READSEL_M          BIT(7)
  29#define BIT_RTC_INTERRUPTS_REG_IT_ALARM_M       BIT(3)
  30#define RTC_STATUS_MASK         0xFE
  31
  32#define SECONDS_REG_MSK         0x7F
  33#define MINUTES_REG_MAK         0x7F
  34#define HOURS_REG_MSK           0x3F
  35#define DAYS_REG_MSK            0x3F
  36#define MONTHS_REG_MSK          0x1F
  37#define YEARS_REG_MSK           0xFF
  38#define WEEKS_REG_MSK           0x7
  39
  40/* REG_SECONDS_REG through REG_YEARS_REG is how many registers? */
  41
  42#define NUM_TIME_REGS   (RK808_WEEKS_REG - RK808_SECONDS_REG + 1)
  43#define NUM_ALARM_REGS  (RK808_ALARM_YEARS_REG - RK808_ALARM_SECONDS_REG + 1)
  44
  45struct rk_rtc_compat_reg {
  46        unsigned int ctrl_reg;
  47        unsigned int status_reg;
  48        unsigned int alarm_seconds_reg;
  49        unsigned int int_reg;
  50        unsigned int seconds_reg;
  51};
  52
  53struct rk808_rtc {
  54        struct rk808 *rk808;
  55        struct rtc_device *rtc;
  56        struct rk_rtc_compat_reg *creg;
  57        int irq;
  58};
  59
  60/*
  61 * The Rockchip calendar used by the RK808 counts November with 31 days. We use
  62 * these translation functions to convert its dates to/from the Gregorian
  63 * calendar used by the rest of the world. We arbitrarily define Jan 1st, 2016
  64 * as the day when both calendars were in sync, and treat all other dates
  65 * relative to that.
  66 * NOTE: Other system software (e.g. firmware) that reads the same hardware must
  67 * implement this exact same conversion algorithm, with the same anchor date.
  68 */
  69static time64_t nov2dec_transitions(struct rtc_time *tm)
  70{
  71        return (tm->tm_year + 1900) - 2016 + (tm->tm_mon + 1 > 11 ? 1 : 0);
  72}
  73
  74static void rockchip_to_gregorian(struct rtc_time *tm)
  75{
  76        /* If it's Nov 31st, rtc_tm_to_time64() will count that like Dec 1st */
  77        time64_t time = rtc_tm_to_time64(tm);
  78        rtc_time64_to_tm(time + nov2dec_transitions(tm) * 86400, tm);
  79}
  80
  81static void gregorian_to_rockchip(struct rtc_time *tm)
  82{
  83        time64_t extra_days = nov2dec_transitions(tm);
  84        time64_t time = rtc_tm_to_time64(tm);
  85        rtc_time64_to_tm(time - extra_days * 86400, tm);
  86
  87        /* Compensate if we went back over Nov 31st (will work up to 2381) */
  88        if (nov2dec_transitions(tm) < extra_days) {
  89                if (tm->tm_mon + 1 == 11)
  90                        tm->tm_mday++;  /* This may result in 31! */
  91                else
  92                        rtc_time64_to_tm(time - (extra_days - 1) * 86400, tm);
  93        }
  94}
  95
  96/* Read current time and date in RTC */
  97static int rk808_rtc_readtime(struct device *dev, struct rtc_time *tm)
  98{
  99        struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 100        struct rk808 *rk808 = rk808_rtc->rk808;
 101        u8 rtc_data[NUM_TIME_REGS];
 102        int ret;
 103
 104        /* Force an update of the shadowed registers right now */
 105        ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
 106                                 BIT_RTC_CTRL_REG_RTC_GET_TIME,
 107                                 BIT_RTC_CTRL_REG_RTC_GET_TIME);
 108        if (ret) {
 109                dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
 110                return ret;
 111        }
 112
 113        /*
 114         * After we set the GET_TIME bit, the rtc time can't be read
 115         * immediately. So we should wait up to 31.25 us, about one cycle of
 116         * 32khz. If we clear the GET_TIME bit here, the time of i2c transfer
 117         * certainly more than 31.25us: 16 * 2.5us at 400kHz bus frequency.
 118         */
 119        ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
 120                                 BIT_RTC_CTRL_REG_RTC_GET_TIME,
 121                                 0);
 122        if (ret) {
 123                dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
 124                return ret;
 125        }
 126
 127        ret = regmap_bulk_read(rk808->regmap, rk808_rtc->creg->seconds_reg,
 128                               rtc_data, NUM_TIME_REGS);
 129        if (ret) {
 130                dev_err(dev, "Failed to bulk read rtc_data: %d\n", ret);
 131                return ret;
 132        }
 133
 134        tm->tm_sec = bcd2bin(rtc_data[0] & SECONDS_REG_MSK);
 135        tm->tm_min = bcd2bin(rtc_data[1] & MINUTES_REG_MAK);
 136        tm->tm_hour = bcd2bin(rtc_data[2] & HOURS_REG_MSK);
 137        tm->tm_mday = bcd2bin(rtc_data[3] & DAYS_REG_MSK);
 138        tm->tm_mon = (bcd2bin(rtc_data[4] & MONTHS_REG_MSK)) - 1;
 139        tm->tm_year = (bcd2bin(rtc_data[5] & YEARS_REG_MSK)) + 100;
 140        tm->tm_wday = bcd2bin(rtc_data[6] & WEEKS_REG_MSK);
 141        rockchip_to_gregorian(tm);
 142        dev_dbg(dev, "RTC date/time %ptRd(%d) %ptRt\n", tm, tm->tm_wday, tm);
 143
 144        return ret;
 145}
 146
 147/* Set current time and date in RTC */
 148static int rk808_rtc_set_time(struct device *dev, struct rtc_time *tm)
 149{
 150        struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 151        struct rk808 *rk808 = rk808_rtc->rk808;
 152        u8 rtc_data[NUM_TIME_REGS];
 153        int ret;
 154
 155        dev_dbg(dev, "set RTC date/time %ptRd(%d) %ptRt\n", tm, tm->tm_wday, tm);
 156        gregorian_to_rockchip(tm);
 157        rtc_data[0] = bin2bcd(tm->tm_sec);
 158        rtc_data[1] = bin2bcd(tm->tm_min);
 159        rtc_data[2] = bin2bcd(tm->tm_hour);
 160        rtc_data[3] = bin2bcd(tm->tm_mday);
 161        rtc_data[4] = bin2bcd(tm->tm_mon + 1);
 162        rtc_data[5] = bin2bcd(tm->tm_year - 100);
 163        rtc_data[6] = bin2bcd(tm->tm_wday);
 164
 165        /* Stop RTC while updating the RTC registers */
 166        ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
 167                                 BIT_RTC_CTRL_REG_STOP_RTC_M,
 168                                 BIT_RTC_CTRL_REG_STOP_RTC_M);
 169        if (ret) {
 170                dev_err(dev, "Failed to update RTC control: %d\n", ret);
 171                return ret;
 172        }
 173
 174        ret = regmap_bulk_write(rk808->regmap, rk808_rtc->creg->seconds_reg,
 175                                rtc_data, NUM_TIME_REGS);
 176        if (ret) {
 177                dev_err(dev, "Failed to bull write rtc_data: %d\n", ret);
 178                return ret;
 179        }
 180        /* Start RTC again */
 181        ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
 182                                 BIT_RTC_CTRL_REG_STOP_RTC_M, 0);
 183        if (ret) {
 184                dev_err(dev, "Failed to update RTC control: %d\n", ret);
 185                return ret;
 186        }
 187        return 0;
 188}
 189
 190/* Read alarm time and date in RTC */
 191static int rk808_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 192{
 193        struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 194        struct rk808 *rk808 = rk808_rtc->rk808;
 195        u8 alrm_data[NUM_ALARM_REGS];
 196        uint32_t int_reg;
 197        int ret;
 198
 199        ret = regmap_bulk_read(rk808->regmap,
 200                               rk808_rtc->creg->alarm_seconds_reg,
 201                               alrm_data, NUM_ALARM_REGS);
 202        if (ret) {
 203                dev_err(dev, "Failed to read RTC alarm date REG: %d\n", ret);
 204                return ret;
 205        }
 206
 207        alrm->time.tm_sec = bcd2bin(alrm_data[0] & SECONDS_REG_MSK);
 208        alrm->time.tm_min = bcd2bin(alrm_data[1] & MINUTES_REG_MAK);
 209        alrm->time.tm_hour = bcd2bin(alrm_data[2] & HOURS_REG_MSK);
 210        alrm->time.tm_mday = bcd2bin(alrm_data[3] & DAYS_REG_MSK);
 211        alrm->time.tm_mon = (bcd2bin(alrm_data[4] & MONTHS_REG_MSK)) - 1;
 212        alrm->time.tm_year = (bcd2bin(alrm_data[5] & YEARS_REG_MSK)) + 100;
 213        rockchip_to_gregorian(&alrm->time);
 214
 215        ret = regmap_read(rk808->regmap, rk808_rtc->creg->int_reg, &int_reg);
 216        if (ret) {
 217                dev_err(dev, "Failed to read RTC INT REG: %d\n", ret);
 218                return ret;
 219        }
 220
 221        dev_dbg(dev, "alrm read RTC date/time %ptRd(%d) %ptRt\n",
 222                &alrm->time, alrm->time.tm_wday, &alrm->time);
 223
 224        alrm->enabled = (int_reg & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M) ? 1 : 0;
 225
 226        return 0;
 227}
 228
 229static int rk808_rtc_stop_alarm(struct rk808_rtc *rk808_rtc)
 230{
 231        struct rk808 *rk808 = rk808_rtc->rk808;
 232        int ret;
 233
 234        ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->int_reg,
 235                                 BIT_RTC_INTERRUPTS_REG_IT_ALARM_M, 0);
 236
 237        return ret;
 238}
 239
 240static int rk808_rtc_start_alarm(struct rk808_rtc *rk808_rtc)
 241{
 242        struct rk808 *rk808 = rk808_rtc->rk808;
 243        int ret;
 244
 245        ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->int_reg,
 246                                 BIT_RTC_INTERRUPTS_REG_IT_ALARM_M,
 247                                 BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
 248
 249        return ret;
 250}
 251
 252static int rk808_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 253{
 254        struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 255        struct rk808 *rk808 = rk808_rtc->rk808;
 256        u8 alrm_data[NUM_ALARM_REGS];
 257        int ret;
 258
 259        ret = rk808_rtc_stop_alarm(rk808_rtc);
 260        if (ret) {
 261                dev_err(dev, "Failed to stop alarm: %d\n", ret);
 262                return ret;
 263        }
 264        dev_dbg(dev, "alrm set RTC date/time %ptRd(%d) %ptRt\n",
 265                &alrm->time, alrm->time.tm_wday, &alrm->time);
 266
 267        gregorian_to_rockchip(&alrm->time);
 268        alrm_data[0] = bin2bcd(alrm->time.tm_sec);
 269        alrm_data[1] = bin2bcd(alrm->time.tm_min);
 270        alrm_data[2] = bin2bcd(alrm->time.tm_hour);
 271        alrm_data[3] = bin2bcd(alrm->time.tm_mday);
 272        alrm_data[4] = bin2bcd(alrm->time.tm_mon + 1);
 273        alrm_data[5] = bin2bcd(alrm->time.tm_year - 100);
 274
 275        ret = regmap_bulk_write(rk808->regmap,
 276                                rk808_rtc->creg->alarm_seconds_reg,
 277                                alrm_data, NUM_ALARM_REGS);
 278        if (ret) {
 279                dev_err(dev, "Failed to bulk write: %d\n", ret);
 280                return ret;
 281        }
 282        if (alrm->enabled) {
 283                ret = rk808_rtc_start_alarm(rk808_rtc);
 284                if (ret) {
 285                        dev_err(dev, "Failed to start alarm: %d\n", ret);
 286                        return ret;
 287                }
 288        }
 289        return 0;
 290}
 291
 292static int rk808_rtc_alarm_irq_enable(struct device *dev,
 293                                      unsigned int enabled)
 294{
 295        struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 296
 297        if (enabled)
 298                return rk808_rtc_start_alarm(rk808_rtc);
 299
 300        return rk808_rtc_stop_alarm(rk808_rtc);
 301}
 302
 303/*
 304 * We will just handle setting the frequency and make use the framework for
 305 * reading the periodic interupts.
 306 *
 307 * @freq: Current periodic IRQ freq:
 308 * bit 0: every second
 309 * bit 1: every minute
 310 * bit 2: every hour
 311 * bit 3: every day
 312 */
 313static irqreturn_t rk808_alarm_irq(int irq, void *data)
 314{
 315        struct rk808_rtc *rk808_rtc = data;
 316        struct rk808 *rk808 = rk808_rtc->rk808;
 317        struct i2c_client *client = rk808->i2c;
 318        int ret;
 319
 320        ret = regmap_write(rk808->regmap, rk808_rtc->creg->status_reg,
 321                           RTC_STATUS_MASK);
 322        if (ret) {
 323                dev_err(&client->dev,
 324                        "%s:Failed to update RTC status: %d\n", __func__, ret);
 325                return ret;
 326        }
 327
 328        rtc_update_irq(rk808_rtc->rtc, 1, RTC_IRQF | RTC_AF);
 329        dev_dbg(&client->dev,
 330                 "%s:irq=%d\n", __func__, irq);
 331        return IRQ_HANDLED;
 332}
 333
 334static const struct rtc_class_ops rk808_rtc_ops = {
 335        .read_time = rk808_rtc_readtime,
 336        .set_time = rk808_rtc_set_time,
 337        .read_alarm = rk808_rtc_readalarm,
 338        .set_alarm = rk808_rtc_setalarm,
 339        .alarm_irq_enable = rk808_rtc_alarm_irq_enable,
 340};
 341
 342#ifdef CONFIG_PM_SLEEP
 343/* Turn off the alarm if it should not be a wake source. */
 344static int rk808_rtc_suspend(struct device *dev)
 345{
 346        struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 347
 348        if (device_may_wakeup(dev))
 349                enable_irq_wake(rk808_rtc->irq);
 350
 351        return 0;
 352}
 353
 354/* Enable the alarm if it should be enabled (in case it was disabled to
 355 * prevent use as a wake source).
 356 */
 357static int rk808_rtc_resume(struct device *dev)
 358{
 359        struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 360
 361        if (device_may_wakeup(dev))
 362                disable_irq_wake(rk808_rtc->irq);
 363
 364        return 0;
 365}
 366#endif
 367
 368static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops,
 369        rk808_rtc_suspend, rk808_rtc_resume);
 370
 371static struct rk_rtc_compat_reg rk808_creg = {
 372        .ctrl_reg = RK808_RTC_CTRL_REG,
 373        .status_reg = RK808_RTC_STATUS_REG,
 374        .alarm_seconds_reg = RK808_ALARM_SECONDS_REG,
 375        .int_reg = RK808_RTC_INT_REG,
 376        .seconds_reg = RK808_SECONDS_REG,
 377};
 378
 379static struct rk_rtc_compat_reg rk817_creg = {
 380        .ctrl_reg = RK817_RTC_CTRL_REG,
 381        .status_reg = RK817_RTC_STATUS_REG,
 382        .alarm_seconds_reg = RK817_ALARM_SECONDS_REG,
 383        .int_reg = RK817_RTC_INT_REG,
 384        .seconds_reg = RK817_SECONDS_REG,
 385};
 386
 387static int rk808_rtc_probe(struct platform_device *pdev)
 388{
 389        struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent);
 390        struct rk808_rtc *rk808_rtc;
 391        int ret;
 392
 393        rk808_rtc = devm_kzalloc(&pdev->dev, sizeof(*rk808_rtc), GFP_KERNEL);
 394        if (rk808_rtc == NULL)
 395                return -ENOMEM;
 396
 397        switch (rk808->variant) {
 398        case RK809_ID:
 399        case RK817_ID:
 400                rk808_rtc->creg = &rk817_creg;
 401                break;
 402        default:
 403                rk808_rtc->creg = &rk808_creg;
 404                break;
 405        }
 406        platform_set_drvdata(pdev, rk808_rtc);
 407        rk808_rtc->rk808 = rk808;
 408
 409        /* start rtc running by default, and use shadowed timer. */
 410        ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
 411                                 BIT_RTC_CTRL_REG_STOP_RTC_M |
 412                                 BIT_RTC_CTRL_REG_RTC_READSEL_M,
 413                                 BIT_RTC_CTRL_REG_RTC_READSEL_M);
 414        if (ret) {
 415                dev_err(&pdev->dev,
 416                        "Failed to update RTC control: %d\n", ret);
 417                return ret;
 418        }
 419
 420        ret = regmap_write(rk808->regmap, rk808_rtc->creg->status_reg,
 421                           RTC_STATUS_MASK);
 422        if (ret) {
 423                dev_err(&pdev->dev,
 424                        "Failed to write RTC status: %d\n", ret);
 425                return ret;
 426        }
 427
 428        device_init_wakeup(&pdev->dev, 1);
 429
 430        rk808_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 431        if (IS_ERR(rk808_rtc->rtc))
 432                return PTR_ERR(rk808_rtc->rtc);
 433
 434        rk808_rtc->rtc->ops = &rk808_rtc_ops;
 435
 436        rk808_rtc->irq = platform_get_irq(pdev, 0);
 437        if (rk808_rtc->irq < 0)
 438                return rk808_rtc->irq;
 439
 440        /* request alarm irq of rk808 */
 441        ret = devm_request_threaded_irq(&pdev->dev, rk808_rtc->irq, NULL,
 442                                        rk808_alarm_irq, 0,
 443                                        "RTC alarm", rk808_rtc);
 444        if (ret) {
 445                dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
 446                        rk808_rtc->irq, ret);
 447                return ret;
 448        }
 449
 450        return devm_rtc_register_device(rk808_rtc->rtc);
 451}
 452
 453static struct platform_driver rk808_rtc_driver = {
 454        .probe = rk808_rtc_probe,
 455        .driver = {
 456                .name = "rk808-rtc",
 457                .pm = &rk808_rtc_pm_ops,
 458        },
 459};
 460
 461module_platform_driver(rk808_rtc_driver);
 462
 463MODULE_DESCRIPTION("RTC driver for the rk808 series PMICs");
 464MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>");
 465MODULE_AUTHOR("Zhang Qing <zhangqing@rock-chips.com>");
 466MODULE_LICENSE("GPL");
 467MODULE_ALIAS("platform:rk808-rtc");
 468