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 %ptRd(%d) %ptRt\n", tm, tm->tm_wday, tm);
 142
 143         return ret;
 144 }
 145
 146 /* Set current time and date in RTC */
 147 static int rk808_rtc_set_time(struct device *dev, struct rtc_time *tm)
 148 {
 149         struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 150         struct rk808 *rk808 = rk808_rtc->rk808;
 151         u8 rtc_data[NUM_TIME_REGS];
 152         int ret;
 153
 154         dev_dbg(dev, "set RTC date/time %ptRd(%d) %ptRt\n", tm, tm->tm_wday, tm);
 155         gregorian_to_rockchip(tm);
 156         rtc_data[0] = bin2bcd(tm->tm_sec);
 157         rtc_data[1] = bin2bcd(tm->tm_min);
 158         rtc_data[2] = bin2bcd(tm->tm_hour);
 159         rtc_data[3] = bin2bcd(tm->tm_mday);
 160         rtc_data[4] = bin2bcd(tm->tm_mon + 1);
 161         rtc_data[5] = bin2bcd(tm->tm_year - 100);
 162         rtc_data[6] = bin2bcd(tm->tm_wday);
 163
 164         /* Stop RTC while updating the RTC registers */
 165         ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 166                                  BIT_RTC_CTRL_REG_STOP_RTC_M,
 167                                  BIT_RTC_CTRL_REG_STOP_RTC_M);
 168         if (ret) {
 169                 dev_err(dev, "Failed to update RTC control: %d\n", ret);
 170                 return ret;
 171         }
 172
 173         ret = regmap_bulk_write(rk808->regmap, RK808_SECONDS_REG,
 174                                 rtc_data, NUM_TIME_REGS);
 175         if (ret) {
 176                 dev_err(dev, "Failed to bull write rtc_data: %d\n", ret);
 177                 return ret;
 178         }
 179         /* Start RTC again */
 180         ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 181                                  BIT_RTC_CTRL_REG_STOP_RTC_M, 0);
 182         if (ret) {
 183                 dev_err(dev, "Failed to update RTC control: %d\n", ret);
 184                 return ret;
 185         }
 186         return 0;
 187 }
 188
 189 /* Read alarm time and date in RTC */
 190 static int rk808_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 191 {
 192         struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 193         struct rk808 *rk808 = rk808_rtc->rk808;
 194         u8 alrm_data[NUM_ALARM_REGS];
 195         uint32_t int_reg;
 196         int ret;
 197
 198         ret = regmap_bulk_read(rk808->regmap, RK808_ALARM_SECONDS_REG,
 199                                alrm_data, NUM_ALARM_REGS);
 200
 201         alrm->time.tm_sec = bcd2bin(alrm_data[0] & SECONDS_REG_MSK);
 202         alrm->time.tm_min = bcd2bin(alrm_data[1] & MINUTES_REG_MAK);
 203         alrm->time.tm_hour = bcd2bin(alrm_data[2] & HOURS_REG_MSK);
 204         alrm->time.tm_mday = bcd2bin(alrm_data[3] & DAYS_REG_MSK);
 205         alrm->time.tm_mon = (bcd2bin(alrm_data[4] & MONTHS_REG_MSK)) - 1;
 206         alrm->time.tm_year = (bcd2bin(alrm_data[5] & YEARS_REG_MSK)) + 100;
 207         rockchip_to_gregorian(&alrm->time);
 208
 209         ret = regmap_read(rk808->regmap, RK808_RTC_INT_REG, &int_reg);
 210         if (ret) {
 211                 dev_err(dev, "Failed to read RTC INT REG: %d\n", ret);
 212                 return ret;
 213         }
 214
 215         dev_dbg(dev, "alrm read RTC date/time %ptRd(%d) %ptRt\n",
 216                 &alrm->time, alrm->time.tm_wday, &alrm->time);
 217
 218         alrm->enabled = (int_reg & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M) ? 1 : 0;
 219
 220         return 0;
 221 }
 222
 223 static int rk808_rtc_stop_alarm(struct rk808_rtc *rk808_rtc)
 224 {
 225         struct rk808 *rk808 = rk808_rtc->rk808;
 226         int ret;
 227
 228         ret = regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG,
 229                                  BIT_RTC_INTERRUPTS_REG_IT_ALARM_M, 0);
 230
 231         return ret;
 232 }
 233
 234 static int rk808_rtc_start_alarm(struct rk808_rtc *rk808_rtc)
 235 {
 236         struct rk808 *rk808 = rk808_rtc->rk808;
 237         int ret;
 238
 239         ret = regmap_update_bits(rk808->regmap, RK808_RTC_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         struct rk808 *rk808 = rk808_rtc->rk808;
 250         u8 alrm_data[NUM_ALARM_REGS];
 251         int ret;
 252
 253         ret = rk808_rtc_stop_alarm(rk808_rtc);
 254         if (ret) {
 255                 dev_err(dev, "Failed to stop alarm: %d\n", ret);
 256                 return ret;
 257         }
 258         dev_dbg(dev, "alrm set RTC date/time %ptRd(%d) %ptRt\n",
 259                 &alrm->time, alrm->time.tm_wday, &alrm->time);
 260
 261         gregorian_to_rockchip(&alrm->time);
 262         alrm_data[0] = bin2bcd(alrm->time.tm_sec);
 263         alrm_data[1] = bin2bcd(alrm->time.tm_min);
 264         alrm_data[2] = bin2bcd(alrm->time.tm_hour);
 265         alrm_data[3] = bin2bcd(alrm->time.tm_mday);
 266         alrm_data[4] = bin2bcd(alrm->time.tm_mon + 1);
 267         alrm_data[5] = bin2bcd(alrm->time.tm_year - 100);
 268
 269         ret = regmap_bulk_write(rk808->regmap, RK808_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         struct rk808 *rk808 = rk808_rtc->rk808;
 310         struct i2c_client *client = rk808->i2c;
 311         int ret;
 312
 313         ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG,
 314                            RTC_STATUS_MASK);
 315         if (ret) {
 316                 dev_err(&client->dev,
 317                         "%s:Failed to update RTC status: %d\n", __func__, ret);
 318                 return ret;
 319         }
 320
 321         rtc_update_irq(rk808_rtc->rtc, 1, RTC_IRQF | RTC_AF);
 322         dev_dbg(&client->dev,
 323                  "%s:irq=%d\n", __func__, irq);
 324         return IRQ_HANDLED;
 325 }
 326
 327 static const struct rtc_class_ops rk808_rtc_ops = {
 328         .read_time = rk808_rtc_readtime,
 329         .set_time = rk808_rtc_set_time,
 330         .read_alarm = rk808_rtc_readalarm,
 331         .set_alarm = rk808_rtc_setalarm,
 332         .alarm_irq_enable = rk808_rtc_alarm_irq_enable,
 333 };
 334
 335 #ifdef CONFIG_PM_SLEEP
 336 /* Turn off the alarm if it should not be a wake source. */
 337 static int rk808_rtc_suspend(struct device *dev)
 338 {
 339         struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 340
 341         if (device_may_wakeup(dev))
 342                 enable_irq_wake(rk808_rtc->irq);
 343
 344         return 0;
 345 }
 346
 347 /* Enable the alarm if it should be enabled (in case it was disabled to
 348  * prevent use as a wake source).
 349  */
 350 static int rk808_rtc_resume(struct device *dev)
 351 {
 352         struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 353
 354         if (device_may_wakeup(dev))
 355                 disable_irq_wake(rk808_rtc->irq);
 356
 357         return 0;
 358 }
 359 #endif
 360
 361 static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops,
 362         rk808_rtc_suspend, rk808_rtc_resume);
 363
 364 static int rk808_rtc_probe(struct platform_device *pdev)
 365 {
 366         struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent);
 367         struct rk808_rtc *rk808_rtc;
 368         int ret;
 369
 370         rk808_rtc = devm_kzalloc(&pdev->dev, sizeof(*rk808_rtc), GFP_KERNEL);
 371         if (rk808_rtc == NULL)
 372                 return -ENOMEM;
 373
 374         platform_set_drvdata(pdev, rk808_rtc);
 375         rk808_rtc->rk808 = rk808;
 376
 377         /* start rtc running by default, and use shadowed timer. */
 378         ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 379                                  BIT_RTC_CTRL_REG_STOP_RTC_M |
 380                                  BIT_RTC_CTRL_REG_RTC_READSEL_M,
 381                                  BIT_RTC_CTRL_REG_RTC_READSEL_M);
 382         if (ret) {
 383                 dev_err(&pdev->dev,
 384                         "Failed to update RTC control: %d\n", ret);
 385                 return ret;
 386         }
 387
 388         ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG,
 389                            RTC_STATUS_MASK);
 390         if (ret) {
 391                 dev_err(&pdev->dev,
 392                         "Failed to write RTC status: %d\n", ret);
 393                 return ret;
 394         }
 395
 396         device_init_wakeup(&pdev->dev, 1);
 397
 398         rk808_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 399         if (IS_ERR(rk808_rtc->rtc))
 400                 return PTR_ERR(rk808_rtc->rtc);
 401
 402         rk808_rtc->rtc->ops = &rk808_rtc_ops;
 403
 404         rk808_rtc->irq = platform_get_irq(pdev, 0);
 405         if (rk808_rtc->irq < 0) {
 406                 if (rk808_rtc->irq != -EPROBE_DEFER)
 407                         dev_err(&pdev->dev, "Wake up is not possible as irq = %d\n",
 408                                 rk808_rtc->irq);
 409                 return rk808_rtc->irq;
 410         }
 411
 412         /* request alarm irq of rk808 */
 413         ret = devm_request_threaded_irq(&pdev->dev, rk808_rtc->irq, NULL,
 414                                         rk808_alarm_irq, 0,
 415                                         "RTC alarm", rk808_rtc);
 416         if (ret) {
 417                 dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
 418                         rk808_rtc->irq, ret);
 419                 return ret;
 420         }
 421
 422         return rtc_register_device(rk808_rtc->rtc);
 423 }
 424
 425 static struct platform_driver rk808_rtc_driver = {
 426         .probe = rk808_rtc_probe,
 427         .driver = {
 428                 .name = "rk808-rtc",
 429                 .pm = &rk808_rtc_pm_ops,
 430         },
 431 };
 432
 433 module_platform_driver(rk808_rtc_driver);
 434
 435 MODULE_DESCRIPTION("RTC driver for the rk808 series PMICs");
 436 MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>");
 437 MODULE_AUTHOR("Zhang Qing <zhangqing@rock-chips.com>");
 438 MODULE_LICENSE("GPL");
 439 MODULE_ALIAS("platform:rk808-rtc");