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
  45 struct 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
  53 struct 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  */
  69 static 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
  74 static 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
  81 static 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 */
  97 static 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 */
 148 static 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 */
 191 static 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
 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->creg->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->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
 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 %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
 292 static 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  */
 313 static 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
 334 static 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. */
 344 static 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  */
 357 static 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
 368 static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops,
 369         rk808_rtc_suspend, rk808_rtc_resume);
 370
 371 static 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
 379 static 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
 387 static 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
 453 static 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
 461 module_platform_driver(rk808_rtc_driver);
 462
 463 MODULE_DESCRIPTION("RTC driver for the rk808 series PMICs");
 464 MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>");
 465 MODULE_AUTHOR("Zhang Qing <zhangqing@rock-chips.com>");
 466 MODULE_LICENSE("GPL");
 467 MODULE_ALIAS("platform:rk808-rtc");