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0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * RTC driver for Rockchip RK808
0004  *
0005  * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
0006  *
0007  * Author: Chris Zhong <zyw@rock-chips.com>
0008  * Author: Zhang Qing <zhangqing@rock-chips.com>
0009  */
0010 
0011 #include <linux/module.h>
0012 #include <linux/kernel.h>
0013 #include <linux/rtc.h>
0014 #include <linux/bcd.h>
0015 #include <linux/mfd/rk808.h>
0016 #include <linux/platform_device.h>
0017 #include <linux/i2c.h>
0018 
0019 /* RTC_CTRL_REG bitfields */
0020 #define BIT_RTC_CTRL_REG_STOP_RTC_M     BIT(0)
0021 
0022 /* RK808 has a shadowed register for saving a "frozen" RTC time.
0023  * When user setting "GET_TIME" to 1, the time will save in this shadowed
0024  * register. If set "READSEL" to 1, user read rtc time register, actually
0025  * get the time of that moment. If we need the real time, clr this bit.
0026  */
0027 #define BIT_RTC_CTRL_REG_RTC_GET_TIME       BIT(6)
0028 #define BIT_RTC_CTRL_REG_RTC_READSEL_M      BIT(7)
0029 #define BIT_RTC_INTERRUPTS_REG_IT_ALARM_M   BIT(3)
0030 #define RTC_STATUS_MASK     0xFE
0031 
0032 #define SECONDS_REG_MSK     0x7F
0033 #define MINUTES_REG_MAK     0x7F
0034 #define HOURS_REG_MSK       0x3F
0035 #define DAYS_REG_MSK        0x3F
0036 #define MONTHS_REG_MSK      0x1F
0037 #define YEARS_REG_MSK       0xFF
0038 #define WEEKS_REG_MSK       0x7
0039 
0040 /* REG_SECONDS_REG through REG_YEARS_REG is how many registers? */
0041 
0042 #define NUM_TIME_REGS   (RK808_WEEKS_REG - RK808_SECONDS_REG + 1)
0043 #define NUM_ALARM_REGS  (RK808_ALARM_YEARS_REG - RK808_ALARM_SECONDS_REG + 1)
0044 
0045 struct rk_rtc_compat_reg {
0046     unsigned int ctrl_reg;
0047     unsigned int status_reg;
0048     unsigned int alarm_seconds_reg;
0049     unsigned int int_reg;
0050     unsigned int seconds_reg;
0051 };
0052 
0053 struct rk808_rtc {
0054     struct rk808 *rk808;
0055     struct rtc_device *rtc;
0056     struct rk_rtc_compat_reg *creg;
0057     int irq;
0058 };
0059 
0060 /*
0061  * The Rockchip calendar used by the RK808 counts November with 31 days. We use
0062  * these translation functions to convert its dates to/from the Gregorian
0063  * calendar used by the rest of the world. We arbitrarily define Jan 1st, 2016
0064  * as the day when both calendars were in sync, and treat all other dates
0065  * relative to that.
0066  * NOTE: Other system software (e.g. firmware) that reads the same hardware must
0067  * implement this exact same conversion algorithm, with the same anchor date.
0068  */
0069 static time64_t nov2dec_transitions(struct rtc_time *tm)
0070 {
0071     return (tm->tm_year + 1900) - 2016 + (tm->tm_mon + 1 > 11 ? 1 : 0);
0072 }
0073 
0074 static void rockchip_to_gregorian(struct rtc_time *tm)
0075 {
0076     /* If it's Nov 31st, rtc_tm_to_time64() will count that like Dec 1st */
0077     time64_t time = rtc_tm_to_time64(tm);
0078     rtc_time64_to_tm(time + nov2dec_transitions(tm) * 86400, tm);
0079 }
0080 
0081 static void gregorian_to_rockchip(struct rtc_time *tm)
0082 {
0083     time64_t extra_days = nov2dec_transitions(tm);
0084     time64_t time = rtc_tm_to_time64(tm);
0085     rtc_time64_to_tm(time - extra_days * 86400, tm);
0086 
0087     /* Compensate if we went back over Nov 31st (will work up to 2381) */
0088     if (nov2dec_transitions(tm) < extra_days) {
0089         if (tm->tm_mon + 1 == 11)
0090             tm->tm_mday++;  /* This may result in 31! */
0091         else
0092             rtc_time64_to_tm(time - (extra_days - 1) * 86400, tm);
0093     }
0094 }
0095 
0096 /* Read current time and date in RTC */
0097 static int rk808_rtc_readtime(struct device *dev, struct rtc_time *tm)
0098 {
0099     struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
0100     struct rk808 *rk808 = rk808_rtc->rk808;
0101     u8 rtc_data[NUM_TIME_REGS];
0102     int ret;
0103 
0104     /* Force an update of the shadowed registers right now */
0105     ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
0106                  BIT_RTC_CTRL_REG_RTC_GET_TIME,
0107                  BIT_RTC_CTRL_REG_RTC_GET_TIME);
0108     if (ret) {
0109         dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
0110         return ret;
0111     }
0112 
0113     /*
0114      * After we set the GET_TIME bit, the rtc time can't be read
0115      * immediately. So we should wait up to 31.25 us, about one cycle of
0116      * 32khz. If we clear the GET_TIME bit here, the time of i2c transfer
0117      * certainly more than 31.25us: 16 * 2.5us at 400kHz bus frequency.
0118      */
0119     ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
0120                  BIT_RTC_CTRL_REG_RTC_GET_TIME,
0121                  0);
0122     if (ret) {
0123         dev_err(dev, "Failed to update bits rtc_ctrl: %d\n", ret);
0124         return ret;
0125     }
0126 
0127     ret = regmap_bulk_read(rk808->regmap, rk808_rtc->creg->seconds_reg,
0128                    rtc_data, NUM_TIME_REGS);
0129     if (ret) {
0130         dev_err(dev, "Failed to bulk read rtc_data: %d\n", ret);
0131         return ret;
0132     }
0133 
0134     tm->tm_sec = bcd2bin(rtc_data[0] & SECONDS_REG_MSK);
0135     tm->tm_min = bcd2bin(rtc_data[1] & MINUTES_REG_MAK);
0136     tm->tm_hour = bcd2bin(rtc_data[2] & HOURS_REG_MSK);
0137     tm->tm_mday = bcd2bin(rtc_data[3] & DAYS_REG_MSK);
0138     tm->tm_mon = (bcd2bin(rtc_data[4] & MONTHS_REG_MSK)) - 1;
0139     tm->tm_year = (bcd2bin(rtc_data[5] & YEARS_REG_MSK)) + 100;
0140     tm->tm_wday = bcd2bin(rtc_data[6] & WEEKS_REG_MSK);
0141     rockchip_to_gregorian(tm);
0142     dev_dbg(dev, "RTC date/time %ptRd(%d) %ptRt\n", tm, tm->tm_wday, tm);
0143 
0144     return ret;
0145 }
0146 
0147 /* Set current time and date in RTC */
0148 static int rk808_rtc_set_time(struct device *dev, struct rtc_time *tm)
0149 {
0150     struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
0151     struct rk808 *rk808 = rk808_rtc->rk808;
0152     u8 rtc_data[NUM_TIME_REGS];
0153     int ret;
0154 
0155     dev_dbg(dev, "set RTC date/time %ptRd(%d) %ptRt\n", tm, tm->tm_wday, tm);
0156     gregorian_to_rockchip(tm);
0157     rtc_data[0] = bin2bcd(tm->tm_sec);
0158     rtc_data[1] = bin2bcd(tm->tm_min);
0159     rtc_data[2] = bin2bcd(tm->tm_hour);
0160     rtc_data[3] = bin2bcd(tm->tm_mday);
0161     rtc_data[4] = bin2bcd(tm->tm_mon + 1);
0162     rtc_data[5] = bin2bcd(tm->tm_year - 100);
0163     rtc_data[6] = bin2bcd(tm->tm_wday);
0164 
0165     /* Stop RTC while updating the RTC registers */
0166     ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
0167                  BIT_RTC_CTRL_REG_STOP_RTC_M,
0168                  BIT_RTC_CTRL_REG_STOP_RTC_M);
0169     if (ret) {
0170         dev_err(dev, "Failed to update RTC control: %d\n", ret);
0171         return ret;
0172     }
0173 
0174     ret = regmap_bulk_write(rk808->regmap, rk808_rtc->creg->seconds_reg,
0175                 rtc_data, NUM_TIME_REGS);
0176     if (ret) {
0177         dev_err(dev, "Failed to bull write rtc_data: %d\n", ret);
0178         return ret;
0179     }
0180     /* Start RTC again */
0181     ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
0182                  BIT_RTC_CTRL_REG_STOP_RTC_M, 0);
0183     if (ret) {
0184         dev_err(dev, "Failed to update RTC control: %d\n", ret);
0185         return ret;
0186     }
0187     return 0;
0188 }
0189 
0190 /* Read alarm time and date in RTC */
0191 static int rk808_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
0192 {
0193     struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
0194     struct rk808 *rk808 = rk808_rtc->rk808;
0195     u8 alrm_data[NUM_ALARM_REGS];
0196     uint32_t int_reg;
0197     int ret;
0198 
0199     ret = regmap_bulk_read(rk808->regmap,
0200                    rk808_rtc->creg->alarm_seconds_reg,
0201                    alrm_data, NUM_ALARM_REGS);
0202     if (ret) {
0203         dev_err(dev, "Failed to read RTC alarm date REG: %d\n", ret);
0204         return ret;
0205     }
0206 
0207     alrm->time.tm_sec = bcd2bin(alrm_data[0] & SECONDS_REG_MSK);
0208     alrm->time.tm_min = bcd2bin(alrm_data[1] & MINUTES_REG_MAK);
0209     alrm->time.tm_hour = bcd2bin(alrm_data[2] & HOURS_REG_MSK);
0210     alrm->time.tm_mday = bcd2bin(alrm_data[3] & DAYS_REG_MSK);
0211     alrm->time.tm_mon = (bcd2bin(alrm_data[4] & MONTHS_REG_MSK)) - 1;
0212     alrm->time.tm_year = (bcd2bin(alrm_data[5] & YEARS_REG_MSK)) + 100;
0213     rockchip_to_gregorian(&alrm->time);
0214 
0215     ret = regmap_read(rk808->regmap, rk808_rtc->creg->int_reg, &int_reg);
0216     if (ret) {
0217         dev_err(dev, "Failed to read RTC INT REG: %d\n", ret);
0218         return ret;
0219     }
0220 
0221     dev_dbg(dev, "alrm read RTC date/time %ptRd(%d) %ptRt\n",
0222         &alrm->time, alrm->time.tm_wday, &alrm->time);
0223 
0224     alrm->enabled = (int_reg & BIT_RTC_INTERRUPTS_REG_IT_ALARM_M) ? 1 : 0;
0225 
0226     return 0;
0227 }
0228 
0229 static int rk808_rtc_stop_alarm(struct rk808_rtc *rk808_rtc)
0230 {
0231     struct rk808 *rk808 = rk808_rtc->rk808;
0232     int ret;
0233 
0234     ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->int_reg,
0235                  BIT_RTC_INTERRUPTS_REG_IT_ALARM_M, 0);
0236 
0237     return ret;
0238 }
0239 
0240 static int rk808_rtc_start_alarm(struct rk808_rtc *rk808_rtc)
0241 {
0242     struct rk808 *rk808 = rk808_rtc->rk808;
0243     int ret;
0244 
0245     ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->int_reg,
0246                  BIT_RTC_INTERRUPTS_REG_IT_ALARM_M,
0247                  BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
0248 
0249     return ret;
0250 }
0251 
0252 static int rk808_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
0253 {
0254     struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
0255     struct rk808 *rk808 = rk808_rtc->rk808;
0256     u8 alrm_data[NUM_ALARM_REGS];
0257     int ret;
0258 
0259     ret = rk808_rtc_stop_alarm(rk808_rtc);
0260     if (ret) {
0261         dev_err(dev, "Failed to stop alarm: %d\n", ret);
0262         return ret;
0263     }
0264     dev_dbg(dev, "alrm set RTC date/time %ptRd(%d) %ptRt\n",
0265         &alrm->time, alrm->time.tm_wday, &alrm->time);
0266 
0267     gregorian_to_rockchip(&alrm->time);
0268     alrm_data[0] = bin2bcd(alrm->time.tm_sec);
0269     alrm_data[1] = bin2bcd(alrm->time.tm_min);
0270     alrm_data[2] = bin2bcd(alrm->time.tm_hour);
0271     alrm_data[3] = bin2bcd(alrm->time.tm_mday);
0272     alrm_data[4] = bin2bcd(alrm->time.tm_mon + 1);
0273     alrm_data[5] = bin2bcd(alrm->time.tm_year - 100);
0274 
0275     ret = regmap_bulk_write(rk808->regmap,
0276                 rk808_rtc->creg->alarm_seconds_reg,
0277                 alrm_data, NUM_ALARM_REGS);
0278     if (ret) {
0279         dev_err(dev, "Failed to bulk write: %d\n", ret);
0280         return ret;
0281     }
0282     if (alrm->enabled) {
0283         ret = rk808_rtc_start_alarm(rk808_rtc);
0284         if (ret) {
0285             dev_err(dev, "Failed to start alarm: %d\n", ret);
0286             return ret;
0287         }
0288     }
0289     return 0;
0290 }
0291 
0292 static int rk808_rtc_alarm_irq_enable(struct device *dev,
0293                       unsigned int enabled)
0294 {
0295     struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
0296 
0297     if (enabled)
0298         return rk808_rtc_start_alarm(rk808_rtc);
0299 
0300     return rk808_rtc_stop_alarm(rk808_rtc);
0301 }
0302 
0303 /*
0304  * We will just handle setting the frequency and make use the framework for
0305  * reading the periodic interupts.
0306  *
0307  * @freq: Current periodic IRQ freq:
0308  * bit 0: every second
0309  * bit 1: every minute
0310  * bit 2: every hour
0311  * bit 3: every day
0312  */
0313 static irqreturn_t rk808_alarm_irq(int irq, void *data)
0314 {
0315     struct rk808_rtc *rk808_rtc = data;
0316     struct rk808 *rk808 = rk808_rtc->rk808;
0317     struct i2c_client *client = rk808->i2c;
0318     int ret;
0319 
0320     ret = regmap_write(rk808->regmap, rk808_rtc->creg->status_reg,
0321                RTC_STATUS_MASK);
0322     if (ret) {
0323         dev_err(&client->dev,
0324             "%s:Failed to update RTC status: %d\n", __func__, ret);
0325         return ret;
0326     }
0327 
0328     rtc_update_irq(rk808_rtc->rtc, 1, RTC_IRQF | RTC_AF);
0329     dev_dbg(&client->dev,
0330          "%s:irq=%d\n", __func__, irq);
0331     return IRQ_HANDLED;
0332 }
0333 
0334 static const struct rtc_class_ops rk808_rtc_ops = {
0335     .read_time = rk808_rtc_readtime,
0336     .set_time = rk808_rtc_set_time,
0337     .read_alarm = rk808_rtc_readalarm,
0338     .set_alarm = rk808_rtc_setalarm,
0339     .alarm_irq_enable = rk808_rtc_alarm_irq_enable,
0340 };
0341 
0342 #ifdef CONFIG_PM_SLEEP
0343 /* Turn off the alarm if it should not be a wake source. */
0344 static int rk808_rtc_suspend(struct device *dev)
0345 {
0346     struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
0347 
0348     if (device_may_wakeup(dev))
0349         enable_irq_wake(rk808_rtc->irq);
0350 
0351     return 0;
0352 }
0353 
0354 /* Enable the alarm if it should be enabled (in case it was disabled to
0355  * prevent use as a wake source).
0356  */
0357 static int rk808_rtc_resume(struct device *dev)
0358 {
0359     struct rk808_rtc *rk808_rtc = dev_get_drvdata(dev);
0360 
0361     if (device_may_wakeup(dev))
0362         disable_irq_wake(rk808_rtc->irq);
0363 
0364     return 0;
0365 }
0366 #endif
0367 
0368 static SIMPLE_DEV_PM_OPS(rk808_rtc_pm_ops,
0369     rk808_rtc_suspend, rk808_rtc_resume);
0370 
0371 static struct rk_rtc_compat_reg rk808_creg = {
0372     .ctrl_reg = RK808_RTC_CTRL_REG,
0373     .status_reg = RK808_RTC_STATUS_REG,
0374     .alarm_seconds_reg = RK808_ALARM_SECONDS_REG,
0375     .int_reg = RK808_RTC_INT_REG,
0376     .seconds_reg = RK808_SECONDS_REG,
0377 };
0378 
0379 static struct rk_rtc_compat_reg rk817_creg = {
0380     .ctrl_reg = RK817_RTC_CTRL_REG,
0381     .status_reg = RK817_RTC_STATUS_REG,
0382     .alarm_seconds_reg = RK817_ALARM_SECONDS_REG,
0383     .int_reg = RK817_RTC_INT_REG,
0384     .seconds_reg = RK817_SECONDS_REG,
0385 };
0386 
0387 static int rk808_rtc_probe(struct platform_device *pdev)
0388 {
0389     struct rk808 *rk808 = dev_get_drvdata(pdev->dev.parent);
0390     struct rk808_rtc *rk808_rtc;
0391     int ret;
0392 
0393     rk808_rtc = devm_kzalloc(&pdev->dev, sizeof(*rk808_rtc), GFP_KERNEL);
0394     if (rk808_rtc == NULL)
0395         return -ENOMEM;
0396 
0397     switch (rk808->variant) {
0398     case RK809_ID:
0399     case RK817_ID:
0400         rk808_rtc->creg = &rk817_creg;
0401         break;
0402     default:
0403         rk808_rtc->creg = &rk808_creg;
0404         break;
0405     }
0406     platform_set_drvdata(pdev, rk808_rtc);
0407     rk808_rtc->rk808 = rk808;
0408 
0409     /* start rtc running by default, and use shadowed timer. */
0410     ret = regmap_update_bits(rk808->regmap, rk808_rtc->creg->ctrl_reg,
0411                  BIT_RTC_CTRL_REG_STOP_RTC_M |
0412                  BIT_RTC_CTRL_REG_RTC_READSEL_M,
0413                  BIT_RTC_CTRL_REG_RTC_READSEL_M);
0414     if (ret) {
0415         dev_err(&pdev->dev,
0416             "Failed to update RTC control: %d\n", ret);
0417         return ret;
0418     }
0419 
0420     ret = regmap_write(rk808->regmap, rk808_rtc->creg->status_reg,
0421                RTC_STATUS_MASK);
0422     if (ret) {
0423         dev_err(&pdev->dev,
0424             "Failed to write RTC status: %d\n", ret);
0425         return ret;
0426     }
0427 
0428     device_init_wakeup(&pdev->dev, 1);
0429 
0430     rk808_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
0431     if (IS_ERR(rk808_rtc->rtc))
0432         return PTR_ERR(rk808_rtc->rtc);
0433 
0434     rk808_rtc->rtc->ops = &rk808_rtc_ops;
0435 
0436     rk808_rtc->irq = platform_get_irq(pdev, 0);
0437     if (rk808_rtc->irq < 0)
0438         return rk808_rtc->irq;
0439 
0440     /* request alarm irq of rk808 */
0441     ret = devm_request_threaded_irq(&pdev->dev, rk808_rtc->irq, NULL,
0442                     rk808_alarm_irq, 0,
0443                     "RTC alarm", rk808_rtc);
0444     if (ret) {
0445         dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
0446             rk808_rtc->irq, ret);
0447         return ret;
0448     }
0449 
0450     return devm_rtc_register_device(rk808_rtc->rtc);
0451 }
0452 
0453 static struct platform_driver rk808_rtc_driver = {
0454     .probe = rk808_rtc_probe,
0455     .driver = {
0456         .name = "rk808-rtc",
0457         .pm = &rk808_rtc_pm_ops,
0458     },
0459 };
0460 
0461 module_platform_driver(rk808_rtc_driver);
0462 
0463 MODULE_DESCRIPTION("RTC driver for the rk808 series PMICs");
0464 MODULE_AUTHOR("Chris Zhong <zyw@rock-chips.com>");
0465 MODULE_AUTHOR("Zhang Qing <zhangqing@rock-chips.com>");
0466 MODULE_LICENSE("GPL");
0467 MODULE_ALIAS("platform:rk808-rtc");
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