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
  18 /* RTC_CTRL_REG bitfields */
  19 #define BIT_RTC_CTRL_REG_STOP_RTC_M             BIT(0)
  20
  21 /* RK808 has a shadowed register for saving a "frozen" RTC time.
  22  * When user setting "GET_TIME" to 1, the time will save in this shadowed
  23  * register. If set "READSEL" to 1, user read rtc time register, actually
  24  * get the time of that moment. If we need the real time, clr this bit.
  25  */
  26 #define BIT_RTC_CTRL_REG_RTC_GET_TIME           BIT(6)
  27 #define BIT_RTC_CTRL_REG_RTC_READSEL_M          BIT(7)
  28 #define BIT_RTC_INTERRUPTS_REG_IT_ALARM_M       BIT(3)
  29 #define RTC_STATUS_MASK         0xFE
  30
  31 #define SECONDS_REG_MSK         0x7F
  32 #define MINUTES_REG_MAK         0x7F
  33 #define HOURS_REG_MSK           0x3F
  34 #define DAYS_REG_MSK            0x3F
  35 #define MONTHS_REG_MSK          0x1F
  36 #define YEARS_REG_MSK           0xFF
  37 #define WEEKS_REG_MSK           0x7
  38
  39 /* REG_SECONDS_REG through REG_YEARS_REG is how many registers? */
  40
  41 #define NUM_TIME_REGS   (RK808_WEEKS_REG - RK808_SECONDS_REG + 1)
  42 #define NUM_ALARM_REGS  (RK808_ALARM_YEARS_REG - RK808_ALARM_SECONDS_REG + 1)
  43
  44 struct rk_rtc_compat_reg {
  45         unsigned int ctrl_reg;
  46         unsigned int status_reg;
  47         unsigned int alarm_seconds_reg;
  48         unsigned int int_reg;
  49         unsigned int seconds_reg;
  50 };
  51
  52 struct rk808_rtc {
  53         struct regmap *regmap;
  54         struct rtc_device *rtc;
  55         struct rk_rtc_compat_reg *creg;
  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         u8 rtc_data[NUM_TIME_REGS];
 100         int ret;
 101
 102         /* Force an update of the shadowed registers right now */
 103         ret = regmap_update_bits(rk808_rtc->regmap, rk808_rtc->creg->ctrl_reg,
 104                                  BIT_RTC_CTRL_REG_RTC_GET_TIME,
 105                                  BIT_RTC_CTRL_REG_RTC_GET_TIME);
 106         if (ret) {
 107                 dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
 108                 return ret;
 109         }
 110
 111         /*
 112          * After we set the GET_TIME bit, the rtc time can't be read
 113          * immediately. So we should wait up to 31.25 us, about one cycle of
 114          * 32khz. If we clear the GET_TIME bit here, the time of i2c transfer
 115          * certainly more than 31.25us: 16 * 2.5us at 400kHz bus frequency.
 116          */
 117         ret = regmap_update_bits(rk808_rtc->regmap, rk808_rtc->creg->ctrl_reg,
 118                                  BIT_RTC_CTRL_REG_RTC_GET_TIME,
 119                                  0);
 120         if (ret) {
 121                 dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
 122                 return ret;
 123         }
 124
 125         ret = regmap_bulk_read(rk808_rtc->regmap, rk808_rtc->creg->seconds_reg,
 126                                rtc_data, NUM_TIME_REGS);
 127         if (ret) {
 128                 dev_err(dev, "Failed to bulk read rtc_data: %d\n", ret);
 129                 return ret;
 130         }
 131
 132         tm->tm_sec = bcd2bin(rtc_data[0] & SECONDS_REG_MSK);
 133         tm->tm_min = bcd2bin(rtc_data[1] & MINUTES_REG_MAK);
 134         tm->tm_hour = bcd2bin(rtc_data[2] & HOURS_REG_MSK);
 135         tm->tm_mday = bcd2bin(rtc_data[3] & DAYS_REG_MSK);
 136         tm->tm_mon = (bcd2bin(rtc_data[4] & MONTHS_REG_MSK)) - 1;
 137         tm->tm_year = (bcd2bin(rtc_data[5] & YEARS_REG_MSK)) + 100;
 138         tm->tm_wday = bcd2bin(rtc_data[6] & WEEKS_REG_MSK);
 139         rockchip_to_gregorian(tm);
 140         dev_dbg(dev, "RTC date/time %ptRd(%d) %ptRt\n", tm, tm->tm_wday, tm);
 141
 142         return ret;
 143 }
 144
 145 /* Set current time and date in RTC */
 146 static int rk808_rtc_set_time(struct device *dev, struct rtc_time *tm)
 147 {
 148         struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 149         u8 rtc_data[NUM_TIME_REGS];
 150         int ret;
 151
 152         dev_dbg(dev, "set RTC date/time %ptRd(%d) %ptRt\n", tm, tm->tm_wday, tm);
 153         gregorian_to_rockchip(tm);
 154         rtc_data[0] = bin2bcd(tm->tm_sec);
 155         rtc_data[1] = bin2bcd(tm->tm_min);
 156         rtc_data[2] = bin2bcd(tm->tm_hour);
 157         rtc_data[3] = bin2bcd(tm->tm_mday);
 158         rtc_data[4] = bin2bcd(tm->tm_mon + 1);
 159         rtc_data[5] = bin2bcd(tm->tm_year - 100);
 160         rtc_data[6] = bin2bcd(tm->tm_wday);
 161
 162         /* Stop RTC while updating the RTC registers */
 163         ret = regmap_update_bits(rk808_rtc->regmap, rk808_rtc->creg->ctrl_reg,
 164                                  BIT_RTC_CTRL_REG_STOP_RTC_M,
 165                                  BIT_RTC_CTRL_REG_STOP_RTC_M);
 166         if (ret) {
 167                 dev_err(dev, "Failed to update RTC control: %d\n", ret);
 168                 return ret;
 169         }
 170
 171         ret = regmap_bulk_write(rk808_rtc->regmap, rk808_rtc->creg->seconds_reg,
 172                                 rtc_data, NUM_TIME_REGS);
 173         if (ret) {
 174                 dev_err(dev, "Failed to bull write rtc_data: %d\n", ret);
 175                 return ret;
 176         }
 177         /* Start RTC again */
 178         ret = regmap_update_bits(rk808_rtc->regmap, rk808_rtc->creg->ctrl_reg,
 179                                  BIT_RTC_CTRL_REG_STOP_RTC_M, 0);
 180         if (ret) {
 181                 dev_err(dev, "Failed to update RTC control: %d\n", ret);
 182                 return ret;
 183         }
 184         return 0;
 185 }
 186
 187 /* Read alarm time and date in RTC */
 188 static int rk808_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 189 {
 190         struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 191         u8 alrm_data[NUM_ALARM_REGS];
 192         uint32_t int_reg;
 193         int ret;
 194
 195         ret = regmap_bulk_read(rk808_rtc->regmap,
 196                                rk808_rtc->creg->alarm_seconds_reg,
 197                                alrm_data, NUM_ALARM_REGS);
 198         if (ret) {
 199                 dev_err(dev, "Failed to read RTC alarm date REG: %d\n", ret);
 200                 return ret;
 201         }
 202
 203         alrm->time.tm_sec = bcd2bin(alrm_data[0] & SECONDS_REG_MSK);
 204         alrm->time.tm_min = bcd2bin(alrm_data[1] & MINUTES_REG_MAK);
 205         alrm->time.tm_hour = bcd2bin(alrm_data[2] & HOURS_REG_MSK);
 206         alrm->time.tm_mday = bcd2bin(alrm_data[3] & DAYS_REG_MSK);
 207         alrm->time.tm_mon = (bcd2bin(alrm_data[4] & MONTHS_REG_MSK)) - 1;
 208         alrm->time.tm_year = (bcd2bin(alrm_data[5] & YEARS_REG_MSK)) + 100;
 209         rockchip_to_gregorian(&alrm->time);
 210
 211         ret = regmap_read(rk808_rtc->regmap, rk808_rtc->creg->int_reg, &int_reg);
 212         if (ret) {
 213                 dev_err(dev, "Failed to read RTC INT REG: %d\n", ret);
 214                 return ret;
 215         }
 216
 217         dev_dbg(dev, "alrm read RTC date/time %ptRd(%d) %ptRt\n",
 218                 &alrm->time, alrm->time.tm_wday, &alrm->time);
 219
 220         alrm->enabled = (int_reg & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M) ? 1 : 0;
 221
 222         return 0;
 223 }
 224
 225 static int rk808_rtc_stop_alarm(struct rk808_rtc *rk808_rtc)
 226 {
 227         int ret;
 228
 229         ret = regmap_update_bits(rk808_rtc->regmap, rk808_rtc->creg->int_reg,
 230                                  BIT_RTC_INTERRUPTS_REG_IT_ALARM_M, 0);
 231
 232         return ret;
 233 }
 234
 235 static int rk808_rtc_start_alarm(struct rk808_rtc *rk808_rtc)
 236 {
 237         int ret;
 238
 239         ret = regmap_update_bits(rk808_rtc->regmap, rk808_rtc->creg->int_reg,
 240                                  BIT_RTC_INTERRUPTS_REG_IT_ALARM_M,
 241                                  BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
 242
 243         return ret;
 244 }
 245
 246 static int rk808_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 247 {
 248         struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 249         u8 alrm_data[NUM_ALARM_REGS];
 250         int ret;
 251
 252         ret = rk808_rtc_stop_alarm(rk808_rtc);
 253         if (ret) {
 254                 dev_err(dev, "Failed to stop alarm: %d\n", ret);
 255                 return ret;
 256         }
 257         dev_dbg(dev, "alrm set RTC date/time %ptRd(%d) %ptRt\n",
 258                 &alrm->time, alrm->time.tm_wday, &alrm->time);
 259
 260         gregorian_to_rockchip(&alrm->time);
 261         alrm_data[0] = bin2bcd(alrm->time.tm_sec);
 262         alrm_data[1] = bin2bcd(alrm->time.tm_min);
 263         alrm_data[2] = bin2bcd(alrm->time.tm_hour);
 264         alrm_data[3] = bin2bcd(alrm->time.tm_mday);
 265         alrm_data[4] = bin2bcd(alrm->time.tm_mon + 1);
 266         alrm_data[5] = bin2bcd(alrm->time.tm_year - 100);
 267
 268         ret = regmap_bulk_write(rk808_rtc->regmap,
 269                                 rk808_rtc->creg->alarm_seconds_reg,
 270                                 alrm_data, NUM_ALARM_REGS);
 271         if (ret) {
 272                 dev_err(dev, "Failed to bulk write: %d\n", ret);
 273                 return ret;
 274         }
 275         if (alrm->enabled) {
 276                 ret = rk808_rtc_start_alarm(rk808_rtc);
 277                 if (ret) {
 278                         dev_err(dev, "Failed to start alarm: %d\n", ret);
 279                         return ret;
 280                 }
 281         }
 282         return 0;
 283 }
 284
 285 static int rk808_rtc_alarm_irq_enable(struct device *dev,
 286                                       unsigned int enabled)
 287 {
 288         struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 289
 290         if (enabled)
 291                 return rk808_rtc_start_alarm(rk808_rtc);
 292
 293         return rk808_rtc_stop_alarm(rk808_rtc);
 294 }
 295
 296 /*
 297  * We will just handle setting the frequency and make use the framework for
 298  * reading the periodic interupts.
 299  *
 300  * @freq: Current periodic IRQ freq:
 301  * bit 0: every second
 302  * bit 1: every minute
 303  * bit 2: every hour
 304  * bit 3: every day
 305  */
 306 static irqreturn_t rk808_alarm_irq(int irq, void *data)
 307 {
 308         struct rk808_rtc *rk808_rtc = data;
 309         int ret;
 310
 311         ret = regmap_write(rk808_rtc->regmap, rk808_rtc->creg->status_reg,
 312                            RTC_STATUS_MASK);
 313         if (ret) {
 314                 dev_err(&rk808_rtc->rtc->dev,
 315                         "%s:Failed to update RTC status: %d\n", __func__, ret);
 316                 return ret;
 317         }
 318
 319         rtc_update_irq(rk808_rtc->rtc, 1, RTC_IRQF | RTC_AF);
 320         dev_dbg(&rk808_rtc->rtc->dev,
 321                  "%s:irq=%d\n", __func__, irq);
 322         return IRQ_HANDLED;
 323 }
 324
 325 static const struct rtc_class_ops rk808_rtc_ops = {
 326         .read_time = rk808_rtc_readtime,
 327         .set_time = rk808_rtc_set_time,
 328         .read_alarm = rk808_rtc_readalarm,
 329         .set_alarm = rk808_rtc_setalarm,
 330         .alarm_irq_enable = rk808_rtc_alarm_irq_enable,
 331 };
 332
 333 #ifdef CONFIG_PM_SLEEP
 334 /* Turn off the alarm if it should not be a wake source. */
 335 static int rk808_rtc_suspend(struct device *dev)
 336 {
 337         struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 338
 339         if (device_may_wakeup(dev))
 340                 enable_irq_wake(rk808_rtc->irq);
 341
 342         return 0;
 343 }
 344
 345 /* Enable the alarm if it should be enabled (in case it was disabled to
 346  * prevent use as a wake source).
 347  */
 348 static int rk808_rtc_resume(struct device *dev)
 349 {
 350         struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 351
 352         if (device_may_wakeup(dev))
 353                 disable_irq_wake(rk808_rtc->irq);
 354
 355         return 0;
 356 }
 357 #endif
 358
 359 static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops,
 360         rk808_rtc_suspend, rk808_rtc_resume);
 361
 362 static struct rk_rtc_compat_reg rk808_creg = {
 363         .ctrl_reg = RK808_RTC_CTRL_REG,
 364         .status_reg = RK808_RTC_STATUS_REG,
 365         .alarm_seconds_reg = RK808_ALARM_SECONDS_REG,
 366         .int_reg = RK808_RTC_INT_REG,
 367         .seconds_reg = RK808_SECONDS_REG,
 368 };
 369
 370 static struct rk_rtc_compat_reg rk817_creg = {
 371         .ctrl_reg = RK817_RTC_CTRL_REG,
 372         .status_reg = RK817_RTC_STATUS_REG,
 373         .alarm_seconds_reg = RK817_ALARM_SECONDS_REG,
 374         .int_reg = RK817_RTC_INT_REG,
 375         .seconds_reg = RK817_SECONDS_REG,
 376 };
 377
 378 static int rk808_rtc_probe(struct platform_device *pdev)
 379 {
 380         struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent);
 381         struct rk808_rtc *rk808_rtc;
 382         int ret;
 383
 384         rk808_rtc = devm_kzalloc(&pdev->dev, sizeof(*rk808_rtc), GFP_KERNEL);
 385         if (rk808_rtc == NULL)
 386                 return -ENOMEM;
 387
 388         switch (rk808->variant) {
 389         case RK809_ID:
 390         case RK817_ID:
 391                 rk808_rtc->creg = &rk817_creg;
 392                 break;
 393         default:
 394                 rk808_rtc->creg = &rk808_creg;
 395                 break;
 396         }
 397         platform_set_drvdata(pdev, rk808_rtc);
 398         rk808_rtc->regmap = dev_get_regmap(pdev->dev.parent, NULL);
 399         if (!rk808_rtc->regmap)
 400                 return -ENODEV;
 401
 402         /* start rtc running by default, and use shadowed timer. */
 403         ret = regmap_update_bits(rk808_rtc->regmap, rk808_rtc->creg->ctrl_reg,
 404                                  BIT_RTC_CTRL_REG_STOP_RTC_M |
 405                                  BIT_RTC_CTRL_REG_RTC_READSEL_M,
 406                                  BIT_RTC_CTRL_REG_RTC_READSEL_M);
 407         if (ret) {
 408                 dev_err(&pdev->dev,
 409                         "Failed to update RTC control: %d\n", ret);
 410                 return ret;
 411         }
 412
 413         ret = regmap_write(rk808_rtc->regmap, rk808_rtc->creg->status_reg,
 414                            RTC_STATUS_MASK);
 415         if (ret) {
 416                 dev_err(&pdev->dev,
 417                         "Failed to write RTC status: %d\n", ret);
 418                 return ret;
 419         }
 420
 421         device_init_wakeup(&pdev->dev, 1);
 422
 423         rk808_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 424         if (IS_ERR(rk808_rtc->rtc))
 425                 return PTR_ERR(rk808_rtc->rtc);
 426
 427         rk808_rtc->rtc->ops = &rk808_rtc_ops;
 428
 429         rk808_rtc->irq = platform_get_irq(pdev, 0);
 430         if (rk808_rtc->irq < 0)
 431                 return rk808_rtc->irq;
 432
 433         /* request alarm irq of rk808 */
 434         ret = devm_request_threaded_irq(&pdev->dev, rk808_rtc->irq, NULL,
 435                                         rk808_alarm_irq, 0,
 436                                         "RTC alarm", rk808_rtc);
 437         if (ret) {
 438                 dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
 439                         rk808_rtc->irq, ret);
 440                 return ret;
 441         }
 442
 443         return devm_rtc_register_device(rk808_rtc->rtc);
 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");