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 /* Read current time and date in RTC */
  60 static int rk808_rtc_readtime(struct device *dev, struct rtc_time *tm)
  61 {
  62         struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
  63         struct rk808 *rk808 = rk808_rtc->rk808;
  64         u8 rtc_data[NUM_TIME_REGS];
  65         int ret;
  66
  67         /* Force an update of the shadowed registers right now */
  68         ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
  69                                  BIT_RTC_CTRL_REG_RTC_GET_TIME,
  70                                  0);
  71         if (ret) {
  72                 dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
  73                 return ret;
  74         }
  75
  76         ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
  77                                  BIT_RTC_CTRL_REG_RTC_GET_TIME,
  78                                  BIT_RTC_CTRL_REG_RTC_GET_TIME);
  79         if (ret) {
  80                 dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
  81                 return ret;
  82         }
  83
  84         ret = regmap_bulk_read(rk808->regmap, RK808_SECONDS_REG,
  85                                rtc_data, NUM_TIME_REGS);
  86         if (ret) {
  87                 dev_err(dev, "Failed to bulk read rtc_data: %d\n", ret);
  88                 return ret;
  89         }
  90
  91         tm->tm_sec = bcd2bin(rtc_data[0] & SECONDS_REG_MSK);
  92         tm->tm_min = bcd2bin(rtc_data[1] & MINUTES_REG_MAK);
  93         tm->tm_hour = bcd2bin(rtc_data[2] & HOURS_REG_MSK);
  94         tm->tm_mday = bcd2bin(rtc_data[3] & DAYS_REG_MSK);
  95         tm->tm_mon = (bcd2bin(rtc_data[4] & MONTHS_REG_MSK)) - 1;
  96         tm->tm_year = (bcd2bin(rtc_data[5] & YEARS_REG_MSK)) + 100;
  97         tm->tm_wday = bcd2bin(rtc_data[6] & WEEKS_REG_MSK);
  98         dev_dbg(dev, "RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
  99                 1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
 100                 tm->tm_wday, tm->tm_hour , tm->tm_min, tm->tm_sec);
 101
 102         return ret;
 103 }
 104
 105 /* Set current time and date in RTC */
 106 static int rk808_rtc_set_time(struct device *dev, struct rtc_time *tm)
 107 {
 108         struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 109         struct rk808 *rk808 = rk808_rtc->rk808;
 110         u8 rtc_data[NUM_TIME_REGS];
 111         int ret;
 112
 113         rtc_data[0] = bin2bcd(tm->tm_sec);
 114         rtc_data[1] = bin2bcd(tm->tm_min);
 115         rtc_data[2] = bin2bcd(tm->tm_hour);
 116         rtc_data[3] = bin2bcd(tm->tm_mday);
 117         rtc_data[4] = bin2bcd(tm->tm_mon + 1);
 118         rtc_data[5] = bin2bcd(tm->tm_year - 100);
 119         rtc_data[6] = bin2bcd(tm->tm_wday);
 120         dev_dbg(dev, "set RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
 121                 1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
 122                 tm->tm_wday, tm->tm_hour , tm->tm_min, tm->tm_sec);
 123
 124         /* Stop RTC while updating the RTC registers */
 125         ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 126                                  BIT_RTC_CTRL_REG_STOP_RTC_M,
 127                                  BIT_RTC_CTRL_REG_STOP_RTC_M);
 128         if (ret) {
 129                 dev_err(dev, "Failed to update RTC control: %d\n", ret);
 130                 return ret;
 131         }
 132
 133         ret = regmap_bulk_write(rk808->regmap, RK808_SECONDS_REG,
 134                                 rtc_data, NUM_TIME_REGS);
 135         if (ret) {
 136                 dev_err(dev, "Failed to bull write rtc_data: %d\n", ret);
 137                 return ret;
 138         }
 139         /* Start RTC again */
 140         ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 141                                  BIT_RTC_CTRL_REG_STOP_RTC_M, 0);
 142         if (ret) {
 143                 dev_err(dev, "Failed to update RTC control: %d\n", ret);
 144                 return ret;
 145         }
 146         return 0;
 147 }
 148
 149 /* Read alarm time and date in RTC */
 150 static int rk808_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 151 {
 152         struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 153         struct rk808 *rk808 = rk808_rtc->rk808;
 154         u8 alrm_data[NUM_ALARM_REGS];
 155         uint32_t int_reg;
 156         int ret;
 157
 158         ret = regmap_bulk_read(rk808->regmap, RK808_ALARM_SECONDS_REG,
 159                                alrm_data, NUM_ALARM_REGS);
 160
 161         alrm->time.tm_sec = bcd2bin(alrm_data[0] & SECONDS_REG_MSK);
 162         alrm->time.tm_min = bcd2bin(alrm_data[1] & MINUTES_REG_MAK);
 163         alrm->time.tm_hour = bcd2bin(alrm_data[2] & HOURS_REG_MSK);
 164         alrm->time.tm_mday = bcd2bin(alrm_data[3] & DAYS_REG_MSK);
 165         alrm->time.tm_mon = (bcd2bin(alrm_data[4] & MONTHS_REG_MSK)) - 1;
 166         alrm->time.tm_year = (bcd2bin(alrm_data[5] & YEARS_REG_MSK)) + 100;
 167
 168         ret = regmap_read(rk808->regmap, RK808_RTC_INT_REG, &int_reg);
 169         if (ret) {
 170                 dev_err(dev, "Failed to read RTC INT REG: %d\n", ret);
 171                 return ret;
 172         }
 173
 174         dev_dbg(dev, "alrm read RTC date/time %4d-%02d-%02d(%d) %02d:%02d:%02d\n",
 175                 1900 + alrm->time.tm_year, alrm->time.tm_mon + 1,
 176                 alrm->time.tm_mday, alrm->time.tm_wday, alrm->time.tm_hour,
 177                 alrm->time.tm_min, alrm->time.tm_sec);
 178
 179         alrm->enabled = (int_reg & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M) ? 1 : 0;
 180
 181         return 0;
 182 }
 183
 184 static int rk808_rtc_stop_alarm(struct rk808_rtc *rk808_rtc)
 185 {
 186         struct rk808 *rk808 = rk808_rtc->rk808;
 187         int ret;
 188
 189         ret = regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG,
 190                                  BIT_RTC_INTERRUPTS_REG_IT_ALARM_M, 0);
 191
 192         return ret;
 193 }
 194
 195 static int rk808_rtc_start_alarm(struct rk808_rtc *rk808_rtc)
 196 {
 197         struct rk808 *rk808 = rk808_rtc->rk808;
 198         int ret;
 199
 200         ret = regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG,
 201                                  BIT_RTC_INTERRUPTS_REG_IT_ALARM_M,
 202                                  BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
 203
 204         return ret;
 205 }
 206
 207 static int rk808_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 208 {
 209         struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 210         struct rk808 *rk808 = rk808_rtc->rk808;
 211         u8 alrm_data[NUM_ALARM_REGS];
 212         int ret;
 213
 214         ret = rk808_rtc_stop_alarm(rk808_rtc);
 215         if (ret) {
 216                 dev_err(dev, "Failed to stop alarm: %d\n", ret);
 217                 return ret;
 218         }
 219         dev_dbg(dev, "alrm set 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_data[0] = bin2bcd(alrm->time.tm_sec);
 225         alrm_data[1] = bin2bcd(alrm->time.tm_min);
 226         alrm_data[2] = bin2bcd(alrm->time.tm_hour);
 227         alrm_data[3] = bin2bcd(alrm->time.tm_mday);
 228         alrm_data[4] = bin2bcd(alrm->time.tm_mon + 1);
 229         alrm_data[5] = bin2bcd(alrm->time.tm_year - 100);
 230
 231         ret = regmap_bulk_write(rk808->regmap, RK808_ALARM_SECONDS_REG,
 232                                 alrm_data, NUM_ALARM_REGS);
 233         if (ret) {
 234                 dev_err(dev, "Failed to bulk write: %d\n", ret);
 235                 return ret;
 236         }
 237         if (alrm->enabled) {
 238                 ret = rk808_rtc_start_alarm(rk808_rtc);
 239                 if (ret) {
 240                         dev_err(dev, "Failed to start alarm: %d\n", ret);
 241                         return ret;
 242                 }
 243         }
 244         return 0;
 245 }
 246
 247 static int rk808_rtc_alarm_irq_enable(struct device *dev,
 248                                       unsigned int enabled)
 249 {
 250         struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
 251
 252         if (enabled)
 253                 return rk808_rtc_start_alarm(rk808_rtc);
 254
 255         return rk808_rtc_stop_alarm(rk808_rtc);
 256 }
 257
 258 /*
 259  * We will just handle setting the frequency and make use the framework for
 260  * reading the periodic interupts.
 261  *
 262  * @freq: Current periodic IRQ freq:
 263  * bit 0: every second
 264  * bit 1: every minute
 265  * bit 2: every hour
 266  * bit 3: every day
 267  */
 268 static irqreturn_t rk808_alarm_irq(int irq, void *data)
 269 {
 270         struct rk808_rtc *rk808_rtc = data;
 271         struct rk808 *rk808 = rk808_rtc->rk808;
 272         struct i2c_client *client = rk808->i2c;
 273         int ret;
 274
 275         ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG,
 276                            RTC_STATUS_MASK);
 277         if (ret) {
 278                 dev_err(&client->dev,
 279                         "%s:Failed to update RTC status: %d\n", __func__, ret);
 280                 return ret;
 281         }
 282
 283         rtc_update_irq(rk808_rtc->rtc, 1, RTC_IRQF | RTC_AF);
 284         dev_dbg(&client->dev,
 285                  "%s:irq=%d\n", __func__, irq);
 286         return IRQ_HANDLED;
 287 }
 288
 289 static const struct rtc_class_ops rk808_rtc_ops = {
 290         .read_time = rk808_rtc_readtime,
 291         .set_time = rk808_rtc_set_time,
 292         .read_alarm = rk808_rtc_readalarm,
 293         .set_alarm = rk808_rtc_setalarm,
 294         .alarm_irq_enable = rk808_rtc_alarm_irq_enable,
 295 };
 296
 297 #ifdef CONFIG_PM_SLEEP
 298 /* Turn off the alarm if it should not be a wake source. */
 299 static int rk808_rtc_suspend(struct device *dev)
 300 {
 301         struct platform_device *pdev = to_platform_device(dev);
 302         struct rk808_rtc *rk808_rtc = dev_get_drvdata(&pdev->dev);
 303
 304         if (device_may_wakeup(dev))
 305                 enable_irq_wake(rk808_rtc->irq);
 306
 307         return 0;
 308 }
 309
 310 /* Enable the alarm if it should be enabled (in case it was disabled to
 311  * prevent use as a wake source).
 312  */
 313 static int rk808_rtc_resume(struct device *dev)
 314 {
 315         struct platform_device *pdev = to_platform_device(dev);
 316         struct rk808_rtc *rk808_rtc = dev_get_drvdata(&pdev->dev);
 317
 318         if (device_may_wakeup(dev))
 319                 disable_irq_wake(rk808_rtc->irq);
 320
 321         return 0;
 322 }
 323 #endif
 324
 325 static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops,
 326         rk808_rtc_suspend, rk808_rtc_resume);
 327
 328 static int rk808_rtc_probe(struct platform_device *pdev)
 329 {
 330         struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent);
 331         struct rk808_rtc *rk808_rtc;
 332         struct rtc_time tm;
 333         int ret;
 334
 335         rk808_rtc = devm_kzalloc(&pdev->dev, sizeof(*rk808_rtc), GFP_KERNEL);
 336         if (rk808_rtc == NULL)
 337                 return -ENOMEM;
 338
 339         platform_set_drvdata(pdev, rk808_rtc);
 340         rk808_rtc->rk808 = rk808;
 341
 342         /* start rtc running by default, and use shadowed timer. */
 343         ret = regmap_update_bits(rk808->regmap, RK808_RTC_CTRL_REG,
 344                                  BIT_RTC_CTRL_REG_STOP_RTC_M |
 345                                  BIT_RTC_CTRL_REG_RTC_READSEL_M,
 346                                  BIT_RTC_CTRL_REG_RTC_READSEL_M);
 347         if (ret) {
 348                 dev_err(&pdev->dev,
 349                         "Failed to update RTC control: %d\n", ret);
 350                 return ret;
 351         }
 352
 353         ret = regmap_write(rk808->regmap, RK808_RTC_STATUS_REG,
 354                            RTC_STATUS_MASK);
 355         if (ret) {
 356                 dev_err(&pdev->dev,
 357                         "Failed to write RTC status: %d\n", ret);
 358                         return ret;
 359         }
 360
 361         /* set init time */
 362         ret = rk808_rtc_readtime(&pdev->dev, &tm);
 363         if (ret) {
 364                 dev_err(&pdev->dev, "Failed to read RTC time\n");
 365                 return ret;
 366         }
 367         ret = rtc_valid_tm(&tm);
 368         if (ret)
 369                 dev_warn(&pdev->dev, "invalid date/time\n");
 370
 371         device_init_wakeup(&pdev->dev, 1);
 372
 373         rk808_rtc->rtc = devm_rtc_device_register(&pdev->dev, "rk808-rtc",
 374                                                   &rk808_rtc_ops, THIS_MODULE);
 375         if (IS_ERR(rk808_rtc->rtc)) {
 376                 ret = PTR_ERR(rk808_rtc->rtc);
 377                 return ret;
 378         }
 379
 380         rk808_rtc->irq = platform_get_irq(pdev, 0);
 381         if (rk808_rtc->irq < 0) {
 382                 if (rk808_rtc->irq != -EPROBE_DEFER)
 383                         dev_err(&pdev->dev, "Wake up is not possible as irq = %d\n",
 384                                 rk808_rtc->irq);
 385                 return rk808_rtc->irq;
 386         }
 387
 388         /* request alarm irq of rk808 */
 389         ret = devm_request_threaded_irq(&pdev->dev, rk808_rtc->irq, NULL,
 390                                         rk808_alarm_irq, 0,
 391                                         "RTC alarm", rk808_rtc);
 392         if (ret) {
 393                 dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
 394                         rk808_rtc->irq, ret);
 395         }
 396
 397         return ret;
 398 }
 399
 400 static struct platform_driver rk808_rtc_driver = {
 401         .probe = rk808_rtc_probe,
 402         .driver = {
 403                 .name = "rk808-rtc",
 404                 .pm = &rk808_rtc_pm_ops,
 405         },
 406 };
 407
 408 module_platform_driver(rk808_rtc_driver);
 409
 410 MODULE_DESCRIPTION("RTC driver for the rk808 series PMICs");
 411 MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>");
 412 MODULE_AUTHOR("Zhang Qing <zhangqing@rock-chips.com>");
 413 MODULE_LICENSE("GPL");
 414 MODULE_ALIAS("platform:rk808-rtc");