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
  53 struct 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  */
  68 static 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
  73 static 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
  80 static 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 */
  96 static 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 */
 149 static 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 */
 194 static 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
 229 static 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
 240 static 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
 252 static 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
 293 static 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  */
 314 static 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
 335 static 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. */
 345 static 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  */
 359 static 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
 371 static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops,
 372         rk808_rtc_suspend, rk808_rtc_resume);
 373
 374 static 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
 446 static 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
 454 module_platform_driver(rk808_rtc_driver);
 455
 456 MODULE_DESCRIPTION("RTC driver for the rk808 series PMICs");
 457 MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>");
 458 MODULE_AUTHOR("Zhang Qing <zhangqing@rock-chips.com>");
 459 MODULE_LICENSE("GPL");
 460 MODULE_ALIAS("platform:rk808-rtc");