drivers/rtc/rtc-rc5t619.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  * drivers/rtc/rtc-rc5t619.c
0004  *
0005  * Real time clock driver for RICOH RC5T619 power management chip.
0006  *
0007  * Copyright (C) 2019 Andreas Kemnade
0008  */
0009
0010 #include <linux/kernel.h>
0011 #include <linux/device.h>
0012 #include <linux/errno.h>
0013 #include <linux/init.h>
0014 #include <linux/module.h>
0015 #include <linux/mfd/rn5t618.h>
0016 #include <linux/platform_device.h>
0017 #include <linux/regmap.h>
0018 #include <linux/bcd.h>
0019 #include <linux/rtc.h>
0020 #include <linux/slab.h>
0021 #include <linux/irqdomain.h>
0022
0023 struct rc5t619_rtc {
0024     int         irq;
0025     struct rtc_device   *rtc;
0026     struct rn5t618 *rn5t618;
0027 };
0028
0029 #define CTRL1_ALARM_ENABLED 0x40
0030 #define CTRL1_24HR 0x20
0031 #define CTRL1_PERIODIC_MASK 0xf
0032
0033 #define CTRL2_PON 0x10
0034 #define CTRL2_ALARM_STATUS 0x80
0035 #define CTRL2_CTFG 0x4
0036 #define CTRL2_CTC 0x1
0037
0038 #define MONTH_CENTFLAG 0x80
0039 #define HOUR_PMFLAG 0x20
0040 #define MDAY_DAL_EXT 0x80
0041
0042 static uint8_t rtc5t619_12hour_bcd2bin(uint8_t hour)
0043 {
0044     if (hour & HOUR_PMFLAG) {
0045         hour = bcd2bin(hour & ~HOUR_PMFLAG);
0046         return hour == 12 ? 12 : 12 + hour;
0047     }
0048
0049     hour = bcd2bin(hour);
0050     return hour == 12 ? 0 : hour;
0051 }
0052
0053 static uint8_t rtc5t619_12hour_bin2bcd(uint8_t hour)
0054 {
0055     if (!hour)
0056         return 0x12;
0057
0058     if (hour < 12)
0059         return bin2bcd(hour);
0060
0061     if (hour == 12)
0062         return 0x12 | HOUR_PMFLAG;
0063
0064     return bin2bcd(hour - 12) | HOUR_PMFLAG;
0065 }
0066
0067 static int rc5t619_rtc_periodic_disable(struct device *dev)
0068 {
0069     struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
0070     int err;
0071
0072     /* disable function */
0073     err = regmap_update_bits(rtc->rn5t618->regmap,
0074                  RN5T618_RTC_CTRL1, CTRL1_PERIODIC_MASK, 0);
0075     if (err < 0)
0076         return err;
0077
0078     /* clear alarm flag and CTFG */
0079     err = regmap_update_bits(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2,
0080                  CTRL2_ALARM_STATUS | CTRL2_CTFG | CTRL2_CTC,
0081                  0);
0082     if (err < 0)
0083         return err;
0084
0085     return 0;
0086 }
0087
0088 /* things to be done once after power on */
0089 static int rc5t619_rtc_pon_setup(struct device *dev)
0090 {
0091     struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
0092     int err;
0093     unsigned int reg_data;
0094
0095     err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &reg_data);
0096     if (err < 0)
0097         return err;
0098
0099     /* clear VDET PON */
0100     reg_data &= ~(CTRL2_PON | CTRL2_CTC | 0x4a);    /* 0101-1011 */
0101     reg_data |= 0x20;   /* 0010-0000 */
0102     err = regmap_write(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, reg_data);
0103     if (err < 0)
0104         return err;
0105
0106     /* clearing RTC Adjust register */
0107     err = regmap_write(rtc->rn5t618->regmap, RN5T618_RTC_ADJUST, 0);
0108     if (err)
0109         return err;
0110
0111     return regmap_update_bits(rtc->rn5t618->regmap,
0112                     RN5T618_RTC_CTRL1,
0113                     CTRL1_24HR, CTRL1_24HR);
0114 }
0115
0116 static int rc5t619_rtc_read_time(struct device *dev, struct rtc_time *tm)
0117 {
0118     struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
0119     u8 buff[7];
0120     int err;
0121     int cent_flag;
0122     unsigned int ctrl1;
0123     unsigned int ctrl2;
0124
0125     err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &ctrl2);
0126     if (err < 0)
0127         return err;
0128
0129     if (ctrl2 & CTRL2_PON)
0130         return -EINVAL;
0131
0132     err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
0133     if (err < 0)
0134         return err;
0135
0136     err = regmap_bulk_read(rtc->rn5t618->regmap, RN5T618_RTC_SECONDS,
0137                    buff, sizeof(buff));
0138     if (err < 0)
0139         return err;
0140
0141     if (buff[5] & MONTH_CENTFLAG)
0142         cent_flag = 1;
0143     else
0144         cent_flag = 0;
0145
0146     tm->tm_sec  = bcd2bin(buff[0]);
0147     tm->tm_min  = bcd2bin(buff[1]);
0148
0149     if (ctrl1 & CTRL1_24HR)
0150         tm->tm_hour = bcd2bin(buff[2]);
0151     else
0152         tm->tm_hour = rtc5t619_12hour_bcd2bin(buff[2]);
0153
0154     tm->tm_wday = bcd2bin(buff[3]);
0155     tm->tm_mday = bcd2bin(buff[4]);
0156     tm->tm_mon  = bcd2bin(buff[5] & 0x1f) - 1; /* back to system 0-11 */
0157     tm->tm_year = bcd2bin(buff[6]) + 100 * cent_flag;
0158
0159     return 0;
0160 }
0161
0162 static int rc5t619_rtc_set_time(struct device *dev, struct rtc_time *tm)
0163 {
0164     struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
0165     u8 buff[7];
0166     int err;
0167     int cent_flag;
0168     unsigned int ctrl1;
0169     unsigned int ctrl2;
0170
0171     err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &ctrl2);
0172     if (err < 0)
0173         return err;
0174
0175     if (ctrl2 & CTRL2_PON)
0176         rc5t619_rtc_pon_setup(dev);
0177
0178     err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
0179     if (err < 0)
0180         return err;
0181
0182     if (tm->tm_year >= 100)
0183         cent_flag = 1;
0184     else
0185         cent_flag = 0;
0186
0187     buff[0] = bin2bcd(tm->tm_sec);
0188     buff[1] = bin2bcd(tm->tm_min);
0189
0190     if (ctrl1 & CTRL1_24HR)
0191         buff[2] = bin2bcd(tm->tm_hour);
0192     else
0193         buff[2] = rtc5t619_12hour_bin2bcd(tm->tm_hour);
0194
0195     buff[3] = bin2bcd(tm->tm_wday);
0196     buff[4] = bin2bcd(tm->tm_mday);
0197     buff[5] = bin2bcd(tm->tm_mon + 1);  /* system set 0-11 */
0198     buff[6] = bin2bcd(tm->tm_year - cent_flag * 100);
0199
0200     if (cent_flag)
0201         buff[5] |= MONTH_CENTFLAG;
0202
0203     err = regmap_bulk_write(rtc->rn5t618->regmap, RN5T618_RTC_SECONDS,
0204                 buff, sizeof(buff));
0205     if (err < 0) {
0206         dev_err(dev, "failed to program new time: %d\n", err);
0207         return err;
0208     }
0209
0210     return 0;
0211 }
0212
0213 /* 0-disable, 1-enable */
0214 static int rc5t619_rtc_alarm_enable(struct device *dev, unsigned int enabled)
0215 {
0216     struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
0217
0218     return regmap_update_bits(rtc->rn5t618->regmap,
0219             RN5T618_RTC_CTRL1,
0220             CTRL1_ALARM_ENABLED,
0221             enabled ? CTRL1_ALARM_ENABLED : 0);
0222 }
0223
0224 static int rc5t619_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
0225 {
0226     struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
0227     u8 buff[6];
0228     unsigned int buff_cent;
0229     int err;
0230     int cent_flag;
0231     unsigned int ctrl1;
0232
0233     err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
0234     if (err)
0235         return err;
0236
0237     err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_MONTH, &buff_cent);
0238     if (err < 0) {
0239         dev_err(dev, "failed to read time: %d\n", err);
0240         return err;
0241     }
0242
0243     if (buff_cent & MONTH_CENTFLAG)
0244         cent_flag = 1;
0245     else
0246         cent_flag = 0;
0247
0248     err = regmap_bulk_read(rtc->rn5t618->regmap, RN5T618_RTC_ALARM_Y_SEC,
0249                    buff, sizeof(buff));
0250     if (err)
0251         return err;
0252
0253     buff[3] = buff[3] & 0x3f;
0254
0255     alrm->time.tm_sec  = bcd2bin(buff[0]);
0256     alrm->time.tm_min  = bcd2bin(buff[1]);
0257
0258     if (ctrl1 & CTRL1_24HR)
0259         alrm->time.tm_hour = bcd2bin(buff[2]);
0260     else
0261         alrm->time.tm_hour = rtc5t619_12hour_bcd2bin(buff[2]);
0262
0263     alrm->time.tm_mday = bcd2bin(buff[3]);
0264     alrm->time.tm_mon  = bcd2bin(buff[4]) - 1;
0265     alrm->time.tm_year = bcd2bin(buff[5]) + 100 * cent_flag;
0266     alrm->enabled = !!(ctrl1 & CTRL1_ALARM_ENABLED);
0267     dev_dbg(dev, "read alarm: %ptR\n", &alrm->time);
0268
0269     return 0;
0270 }
0271
0272 static int rc5t619_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
0273 {
0274     struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
0275     u8 buff[6];
0276     int err;
0277     int cent_flag;
0278     unsigned int ctrl1;
0279
0280     err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
0281     if (err)
0282         return err;
0283
0284     err = rc5t619_rtc_alarm_enable(dev, 0);
0285     if (err < 0)
0286         return err;
0287
0288     if (rtc->irq == -1)
0289         return -EINVAL;
0290
0291     if (alrm->enabled == 0)
0292         return 0;
0293
0294     if (alrm->time.tm_year >= 100)
0295         cent_flag = 1;
0296     else
0297         cent_flag = 0;
0298
0299     alrm->time.tm_mon += 1;
0300     buff[0] = bin2bcd(alrm->time.tm_sec);
0301     buff[1] = bin2bcd(alrm->time.tm_min);
0302
0303     if (ctrl1 & CTRL1_24HR)
0304         buff[2] = bin2bcd(alrm->time.tm_hour);
0305     else
0306         buff[2] = rtc5t619_12hour_bin2bcd(alrm->time.tm_hour);
0307
0308     buff[3] = bin2bcd(alrm->time.tm_mday);
0309     buff[4] = bin2bcd(alrm->time.tm_mon);
0310     buff[5] = bin2bcd(alrm->time.tm_year - 100 * cent_flag);
0311     buff[3] |= MDAY_DAL_EXT;
0312
0313     err = regmap_bulk_write(rtc->rn5t618->regmap, RN5T618_RTC_ALARM_Y_SEC,
0314                 buff, sizeof(buff));
0315     if (err < 0)
0316         return err;
0317
0318     return rc5t619_rtc_alarm_enable(dev, alrm->enabled);
0319 }
0320
0321 static const struct rtc_class_ops rc5t619_rtc_ops = {
0322     .read_time  = rc5t619_rtc_read_time,
0323     .set_time   = rc5t619_rtc_set_time,
0324     .set_alarm  = rc5t619_rtc_set_alarm,
0325     .read_alarm = rc5t619_rtc_read_alarm,
0326     .alarm_irq_enable = rc5t619_rtc_alarm_enable,
0327 };
0328
0329 static int rc5t619_rtc_alarm_flag_clr(struct device *dev)
0330 {
0331     struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
0332
0333     /* clear alarm-D status bits.*/
0334     return regmap_update_bits(rtc->rn5t618->regmap,
0335                 RN5T618_RTC_CTRL2,
0336                 CTRL2_ALARM_STATUS | CTRL2_CTC, 0);
0337 }
0338
0339 static irqreturn_t rc5t619_rtc_irq(int irq, void *data)
0340 {
0341     struct device *dev = data;
0342     struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
0343
0344     rc5t619_rtc_alarm_flag_clr(dev);
0345
0346     rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
0347     return IRQ_HANDLED;
0348 }
0349
0350 static int rc5t619_rtc_probe(struct platform_device *pdev)
0351 {
0352     struct device *dev = &pdev->dev;
0353     struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
0354     struct rc5t619_rtc *rtc;
0355     unsigned int ctrl2;
0356     int err;
0357
0358     rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
0359     if (!rtc)
0360         return -ENOMEM;
0361
0362     rtc->rn5t618 = rn5t618;
0363
0364     dev_set_drvdata(dev, rtc);
0365     rtc->irq = -1;
0366
0367     if (rn5t618->irq_data)
0368         rtc->irq = regmap_irq_get_virq(rn5t618->irq_data,
0369                            RN5T618_IRQ_RTC);
0370
0371     if (rtc->irq  < 0)
0372         rtc->irq = -1;
0373
0374     err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &ctrl2);
0375     if (err < 0)
0376         return err;
0377
0378     /* disable rtc periodic function */
0379     err = rc5t619_rtc_periodic_disable(&pdev->dev);
0380     if (err)
0381         return err;
0382
0383     if (ctrl2 & CTRL2_PON) {
0384         err = rc5t619_rtc_alarm_flag_clr(&pdev->dev);
0385         if (err)
0386             return err;
0387     }
0388
0389     rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
0390     if (IS_ERR(rtc->rtc)) {
0391         err = PTR_ERR(rtc->rtc);
0392         dev_err(dev, "RTC device register: err %d\n", err);
0393         return err;
0394     }
0395
0396     rtc->rtc->ops = &rc5t619_rtc_ops;
0397     rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
0398     rtc->rtc->range_max = RTC_TIMESTAMP_END_2099;
0399
0400     /* set interrupt and enable it */
0401     if (rtc->irq != -1) {
0402         err = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
0403                         rc5t619_rtc_irq,
0404                         IRQF_ONESHOT,
0405                         "rtc-rc5t619",
0406                         &pdev->dev);
0407         if (err < 0) {
0408             dev_err(&pdev->dev, "request IRQ:%d fail\n", rtc->irq);
0409             rtc->irq = -1;
0410
0411             err = rc5t619_rtc_alarm_enable(&pdev->dev, 0);
0412             if (err)
0413                 return err;
0414
0415         } else {
0416             /* enable wake */
0417             device_init_wakeup(&pdev->dev, 1);
0418             enable_irq_wake(rtc->irq);
0419         }
0420     } else {
0421         /* system don't want to using alarm interrupt, so close it */
0422         err = rc5t619_rtc_alarm_enable(&pdev->dev, 0);
0423         if (err)
0424             return err;
0425
0426         dev_warn(&pdev->dev, "rc5t619 interrupt is disabled\n");
0427     }
0428
0429     return devm_rtc_register_device(rtc->rtc);
0430 }
0431
0432 static struct platform_driver rc5t619_rtc_driver = {
0433     .driver = {
0434         .name   = "rc5t619-rtc",
0435     },
0436     .probe  = rc5t619_rtc_probe,
0437 };
0438
0439 module_platform_driver(rc5t619_rtc_driver);
0440 MODULE_ALIAS("platform:rc5t619-rtc");
0441 MODULE_DESCRIPTION("RICOH RC5T619 RTC driver");
0442 MODULE_LICENSE("GPL");