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

   1/*
   2 * RTC driver for Rockchip RK808
   3 *
   4 * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
   5 *
   6 * Author: Chris Zhong <zyw@rock-chips.com>
   7 * Author: Zhang Qing <zhangqing@rock-chips.com>
   8 *
   9 * This program is free software; you can redistribute it and/or modify it
  10 * under the terms and conditions of the GNU General Public License,
  11 * version 2, as published by the Free Software Foundation.
  12 *
  13 * This program is distributed in the hope it will be useful, but WITHOUT
  14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  16 * more details.
  17 */
  18
  19#include <linux/module.h>
  20#include <linux/kernel.h>
  21#include <linux/rtc.h>
  22#include <linux/bcd.h>
  23#include <linux/mfd/rk808.h>
  24#include <linux/platform_device.h>
  25#include <linux/i2c.h>
  26
  27/* RTC_CTRL_REG bitfields */
  28#define BIT_RTC_CTRL_REG_STOP_RTC_M             BIT(0)
  29
  30/* RK808 has a shadowed register for saving a "frozen" RTC time.
  31 * When user setting "GET_TIME" to 1, the time will save in this shadowed
  32 * register. If set "READSEL" to 1, user read rtc time register, actually
  33 * get the time of that moment. If we need the real time, clr this bit.
  34 */
  35#define BIT_RTC_CTRL_REG_RTC_GET_TIME           BIT(6)
  36#define BIT_RTC_CTRL_REG_RTC_READSEL_M          BIT(7)
  37#define BIT_RTC_INTERRUPTS_REG_IT_ALARM_M       BIT(3)
  38#define RTC_STATUS_MASK         0xFE
  39
  40#define SECONDS_REG_MSK         0x7F
  41#define MINUTES_REG_MAK         0x7F
  42#define HOURS_REG_MSK           0x3F
  43#define DAYS_REG_MSK            0x3F
  44#define MONTHS_REG_MSK          0x1F
  45#define YEARS_REG_MSK           0xFF
  46#define WEEKS_REG_MSK           0x7
  47
  48/* REG_SECONDS_REG through REG_YEARS_REG is how many registers? */
  49
  50#define NUM_TIME_REGS   (RK808_WEEKS_REG - RK808_SECONDS_REG + 1)
  51#define NUM_ALARM_REGS  (RK808_ALARM_YEARS_REG - RK808_ALARM_SECONDS_REG + 1)
  52
  53struct rk808_rtc {
  54        struct rk808 *rk808;
  55        struct rtc_device *rtc;
  56        int irq;
  57};
  58
  59/*
  60 * The Rockchip calendar used by the RK808 counts November with 31 days. We use
  61 * these translation functions to convert its dates to/from the Gregorian
  62 * calendar used by the rest of the world. We arbitrarily define Jan 1st, 2016
  63 * as the day when both calendars were in sync, and treat all other dates
  64 * relative to that.
  65 * NOTE: Other system software (e.g. firmware) that reads the same hardware must
  66 * implement this exact same conversion algorithm, with the same anchor date.
  67 */
  68static time64_t nov2dec_transitions(struct rtc_time *tm)
  69{
  70        return (tm->tm_year + 1900) - 2016 + (tm->tm_mon + 1 > 11 ? 1 : 0);
  71}
  72
  73static void rockchip_to_gregorian(struct rtc_time *tm)
  74{
  75        /* If it's Nov 31st, rtc_tm_to_time64() will count that like Dec 1st */
  76        time64_t time = rtc_tm_to_time64(tm);
  77        rtc_time64_to_tm(time + nov2dec_transitions(tm) * 86400, tm);
  78}
  79
  80static void gregorian_to_rockchip(struct rtc_time *tm)
  81{
  82        time64_t extra_days = nov2dec_transitions(tm);
  83        time64_t time = rtc_tm_to_time64(tm);
  84        rtc_time64_to_tm(time - extra_days * 86400, tm);
  85
  86        /* Compensate if we went back over Nov 31st (will work up to 2381) */
  87        if (nov2dec_transitions(tm) < extra_days) {
  88                if (tm->tm_mon + 1 == 11)
  89                        tm->tm_mday++;  /* This may result in 31! */
  90                else
  91                        rtc_time64_to_tm(time - (extra_days - 1) * 86400, tm);
  92        }
  93}
  94
  95/* Read current time and date in RTC */
  96static int rk808_rtc_readtime(struct device *dev, struct rtc_time *tm)
  97{
  98        struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
  99        struct rk808 *rk808 = rk808_rtc->rk808;
 100        u8 rtc_data[NUM_TIME_REGS];
 101        int ret;
 102
 103        /* Force an update of the shadowed registers right now */
 104        ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 105                                 BIT_RTC_CTRL_REG_RTC_GET_TIME,
 106                                 BIT_RTC_CTRL_REG_RTC_GET_TIME);
 107        if (ret) {
 108                dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
 109                return ret;
 110        }
 111
 112        /*
 113         * After we set the GET_TIME bit, the rtc time can't be read
 114         * immediately. So we should wait up to 31.25 us, about one cycle of
 115         * 32khz. If we clear the GET_TIME bit here, the time of i2c transfer
 116         * certainly more than 31.25us: 16 * 2.5us at 400kHz bus frequency.
 117         */
 118        ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 119                                 BIT_RTC_CTRL_REG_RTC_GET_TIME,
 120                                 0);
 121        if (ret) {
 122                dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
 123                return ret;
 124        }
 125
 126        ret = regmap_bulk_read(rk808->regmap, RK808_SECONDS_REG,
 127                               rtc_data, NUM_TIME_REGS);
 128        if (ret) {
 129                dev_err(dev, "Failed to bulk read rtc_data: %d\n", ret);
 130                return ret;
 131        }
 132
 133        tm->tm_sec = bcd2bin(rtc_data[0] & SECONDS_REG_MSK);
 134        tm->tm_min = bcd2bin(rtc_data[1] & MINUTES_REG_MAK);
 135        tm->tm_hour = bcd2bin(rtc_data[2] & HOURS_REG_MSK);
 136        tm->tm_mday = bcd2bin(rtc_data[3] & DAYS_REG_MSK);
 137        tm->tm_mon = (bcd2bin(rtc_data[4] & MONTHS_REG_MSK)) - 1;
 138        tm->tm_year = (bcd2bin(rtc_data[5] & YEARS_REG_MSK)) + 100;
 139        tm->tm_wday = bcd2bin(rtc_data[6] & WEEKS_REG_MSK);
 140        rockchip_to_gregorian(tm);
 141        dev_dbg(dev, "RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
 142                1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
 143                tm->tm_wday, tm->tm_hour, tm->tm_min, tm->tm_sec);
 144
 145        return ret;
 146}
 147
 148/* Set current time and date in RTC */
 149static int rk808_rtc_set_time(struct device *dev, struct rtc_time *tm)
 150{
 151        struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 152        struct rk808 *rk808 = rk808_rtc->rk808;
 153        u8 rtc_data[NUM_TIME_REGS];
 154        int ret;
 155
 156        dev_dbg(dev, "set RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
 157                1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
 158                tm->tm_wday, tm->tm_hour, tm->tm_min, tm->tm_sec);
 159        gregorian_to_rockchip(tm);
 160        rtc_data[0] = bin2bcd(tm->tm_sec);
 161        rtc_data[1] = bin2bcd(tm->tm_min);
 162        rtc_data[2] = bin2bcd(tm->tm_hour);
 163        rtc_data[3] = bin2bcd(tm->tm_mday);
 164        rtc_data[4] = bin2bcd(tm->tm_mon + 1);
 165        rtc_data[5] = bin2bcd(tm->tm_year - 100);
 166        rtc_data[6] = bin2bcd(tm->tm_wday);
 167
 168        /* Stop RTC while updating the RTC registers */
 169        ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 170                                 BIT_RTC_CTRL_REG_STOP_RTC_M,
 171                                 BIT_RTC_CTRL_REG_STOP_RTC_M);
 172        if (ret) {
 173                dev_err(dev, "Failed to update RTC control: %d\n", ret);
 174                return ret;
 175        }
 176
 177        ret = regmap_bulk_write(rk808->regmap, RK808_SECONDS_REG,
 178                                rtc_data, NUM_TIME_REGS);
 179        if (ret) {
 180                dev_err(dev, "Failed to bull write rtc_data: %d\n", ret);
 181                return ret;
 182        }
 183        /* Start RTC again */
 184        ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 185                                 BIT_RTC_CTRL_REG_STOP_RTC_M, 0);
 186        if (ret) {
 187                dev_err(dev, "Failed to update RTC control: %d\n", ret);
 188                return ret;
 189        }
 190        return 0;
 191}
 192
 193/* Read alarm time and date in RTC */
 194static int rk808_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 195{
 196        struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 197        struct rk808 *rk808 = rk808_rtc->rk808;
 198        u8 alrm_data[NUM_ALARM_REGS];
 199        uint32_t int_reg;
 200        int ret;
 201
 202        ret = regmap_bulk_read(rk808->regmap, RK808_ALARM_SECONDS_REG,
 203                               alrm_data, NUM_ALARM_REGS);
 204
 205        alrm->time.tm_sec = bcd2bin(alrm_data[0] & SECONDS_REG_MSK);
 206        alrm->time.tm_min = bcd2bin(alrm_data[1] & MINUTES_REG_MAK);
 207        alrm->time.tm_hour = bcd2bin(alrm_data[2] & HOURS_REG_MSK);
 208        alrm->time.tm_mday = bcd2bin(alrm_data[3] & DAYS_REG_MSK);
 209        alrm->time.tm_mon = (bcd2bin(alrm_data[4] & MONTHS_REG_MSK)) - 1;
 210        alrm->time.tm_year = (bcd2bin(alrm_data[5] & YEARS_REG_MSK)) + 100;
 211        rockchip_to_gregorian(&alrm->time);
 212
 213        ret = regmap_read(rk808->regmap, RK808_RTC_INT_REG, &int_reg);
 214        if (ret) {
 215                dev_err(dev, "Failed to read RTC INT REG: %d\n", ret);
 216                return ret;
 217        }
 218
 219        dev_dbg(dev, "alrm read RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
 220                1900 + alrm->time.tm_year, alrm->time.tm_mon + 1,
 221                alrm->time.tm_mday, alrm->time.tm_wday, alrm->time.tm_hour,
 222                alrm->time.tm_min, alrm->time.tm_sec);
 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_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_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 %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
 265                1900 + alrm->time.tm_year, alrm->time.tm_mon + 1,
 266                alrm->time.tm_mday, alrm->time.tm_wday, alrm->time.tm_hour,
 267                alrm->time.tm_min, alrm->time.tm_sec);
 268
 269        gregorian_to_rockchip(&alrm->time);
 270        alrm_data[0] = bin2bcd(alrm->time.tm_sec);
 271        alrm_data[1] = bin2bcd(alrm->time.tm_min);
 272        alrm_data[2] = bin2bcd(alrm->time.tm_hour);
 273        alrm_data[3] = bin2bcd(alrm->time.tm_mday);
 274        alrm_data[4] = bin2bcd(alrm->time.tm_mon + 1);
 275        alrm_data[5] = bin2bcd(alrm->time.tm_year - 100);
 276
 277        ret = regmap_bulk_write(rk808->regmap, RK808_ALARM_SECONDS_REG,
 278                                alrm_data, NUM_ALARM_REGS);
 279        if (ret) {
 280                dev_err(dev, "Failed to bulk write: %d\n", ret);
 281                return ret;
 282        }
 283        if (alrm->enabled) {
 284                ret = rk808_rtc_start_alarm(rk808_rtc);
 285                if (ret) {
 286                        dev_err(dev, "Failed to start alarm: %d\n", ret);
 287                        return ret;
 288                }
 289        }
 290        return 0;
 291}
 292
 293static int rk808_rtc_alarm_irq_enable(struct device *dev,
 294                                      unsigned int enabled)
 295{
 296        struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 297
 298        if (enabled)
 299                return rk808_rtc_start_alarm(rk808_rtc);
 300
 301        return rk808_rtc_stop_alarm(rk808_rtc);
 302}
 303
 304/*
 305 * We will just handle setting the frequency and make use the framework for
 306 * reading the periodic interupts.
 307 *
 308 * @freq: Current periodic IRQ freq:
 309 * bit 0: every second
 310 * bit 1: every minute
 311 * bit 2: every hour
 312 * bit 3: every day
 313 */
 314static irqreturn_t rk808_alarm_irq(int irq, void *data)
 315{
 316        struct rk808_rtc *rk808_rtc = data;
 317        struct rk808 *rk808 = rk808_rtc->rk808;
 318        struct i2c_client *client = rk808->i2c;
 319        int ret;
 320
 321        ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG,
 322                           RTC_STATUS_MASK);
 323        if (ret) {
 324                dev_err(&client->dev,
 325                        "%s:Failed to update RTC status: %d\n", __func__, ret);
 326                return ret;
 327        }
 328
 329        rtc_update_irq(rk808_rtc->rtc, 1, RTC_IRQF | RTC_AF);
 330        dev_dbg(&client->dev,
 331                 "%s:irq=%d\n", __func__, irq);
 332        return IRQ_HANDLED;
 333}
 334
 335static const struct rtc_class_ops rk808_rtc_ops = {
 336        .read_time = rk808_rtc_readtime,
 337        .set_time = rk808_rtc_set_time,
 338        .read_alarm = rk808_rtc_readalarm,
 339        .set_alarm = rk808_rtc_setalarm,
 340        .alarm_irq_enable = rk808_rtc_alarm_irq_enable,
 341};
 342
 343#ifdef CONFIG_PM_SLEEP
 344/* Turn off the alarm if it should not be a wake source. */
 345static int rk808_rtc_suspend(struct device *dev)
 346{
 347        struct platform_device *pdev = to_platform_device(dev);
 348        struct rk808_rtc *rk808_rtc = dev_get_drvdata(&pdev->dev);
 349
 350        if (device_may_wakeup(dev))
 351                enable_irq_wake(rk808_rtc->irq);
 352
 353        return 0;
 354}
 355
 356/* Enable the alarm if it should be enabled (in case it was disabled to
 357 * prevent use as a wake source).
 358 */
 359static int rk808_rtc_resume(struct device *dev)
 360{
 361        struct platform_device *pdev = to_platform_device(dev);
 362        struct rk808_rtc *rk808_rtc = dev_get_drvdata(&pdev->dev);
 363
 364        if (device_may_wakeup(dev))
 365                disable_irq_wake(rk808_rtc->irq);
 366
 367        return 0;
 368}
 369#endif
 370
 371static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops,
 372        rk808_rtc_suspend, rk808_rtc_resume);
 373
 374static int rk808_rtc_probe(struct platform_device *pdev)
 375{
 376        struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent);
 377        struct rk808_rtc *rk808_rtc;
 378        struct rtc_time tm;
 379        int ret;
 380
 381        rk808_rtc = devm_kzalloc(&pdev->dev, sizeof(*rk808_rtc), GFP_KERNEL);
 382        if (rk808_rtc == NULL)
 383                return -ENOMEM;
 384
 385        platform_set_drvdata(pdev, rk808_rtc);
 386        rk808_rtc->rk808 = rk808;
 387
 388        /* start rtc running by default, and use shadowed timer. */
 389        ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 390                                 BIT_RTC_CTRL_REG_STOP_RTC_M |
 391                                 BIT_RTC_CTRL_REG_RTC_READSEL_M,
 392                                 BIT_RTC_CTRL_REG_RTC_READSEL_M);
 393        if (ret) {
 394                dev_err(&pdev->dev,
 395                        "Failed to update RTC control: %d\n", ret);
 396                return ret;
 397        }
 398
 399        ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG,
 400                           RTC_STATUS_MASK);
 401        if (ret) {
 402                dev_err(&pdev->dev,
 403                        "Failed to write RTC status: %d\n", ret);
 404                        return ret;
 405        }
 406
 407        /* set init time */
 408        ret = rk808_rtc_readtime(&pdev->dev, &tm);
 409        if (ret) {
 410                dev_err(&pdev->dev, "Failed to read RTC time\n");
 411                return ret;
 412        }
 413        ret = rtc_valid_tm(&tm);
 414        if (ret)
 415                dev_warn(&pdev->dev, "invalid date/time\n");
 416
 417        device_init_wakeup(&pdev->dev, 1);
 418
 419        rk808_rtc->rtc = devm_rtc_device_register(&pdev->dev, "rk808-rtc",
 420                                                  &rk808_rtc_ops, THIS_MODULE);
 421        if (IS_ERR(rk808_rtc->rtc)) {
 422                ret = PTR_ERR(rk808_rtc->rtc);
 423                return ret;
 424        }
 425
 426        rk808_rtc->irq = platform_get_irq(pdev, 0);
 427        if (rk808_rtc->irq < 0) {
 428                if (rk808_rtc->irq != -EPROBE_DEFER)
 429                        dev_err(&pdev->dev, "Wake up is not possible as irq = %d\n",
 430                                rk808_rtc->irq);
 431                return rk808_rtc->irq;
 432        }
 433
 434        /* request alarm irq of rk808 */
 435        ret = devm_request_threaded_irq(&pdev->dev, rk808_rtc->irq, NULL,
 436                                        rk808_alarm_irq, 0,
 437                                        "RTC alarm", rk808_rtc);
 438        if (ret) {
 439                dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
 440                        rk808_rtc->irq, ret);
 441        }
 442
 443        return ret;
 444}
 445
 446static struct platform_driver rk808_rtc_driver = {
 447        .probe = rk808_rtc_probe,
 448        .driver = {
 449                .name = "rk808-rtc",
 450                .pm = &rk808_rtc_pm_ops,
 451        },
 452};
 453
 454module_platform_driver(rk808_rtc_driver);
 455
 456MODULE_DESCRIPTION("RTC driver for the rk808 series PMICs");
 457MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>");
 458MODULE_AUTHOR("Zhang Qing <zhangqing@rock-chips.com>");
 459MODULE_LICENSE("GPL");
 460MODULE_ALIAS("platform:rk808-rtc");
 461