drivers/rtc/rtc-rc5t619.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * drivers/rtc/rtc-rc5t619.c
   4  *
   5  * Real time clock driver for RICOH RC5T619 power management chip.
   6  *
   7  * Copyright (C) 2019 Andreas Kemnade
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/device.h>
  12 #include <linux/errno.h>
  13 #include <linux/init.h>
  14 #include <linux/module.h>
  15 #include <linux/mfd/rn5t618.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/regmap.h>
  18 #include <linux/bcd.h>
  19 #include <linux/rtc.h>
  20 #include <linux/slab.h>
  21 #include <linux/irqdomain.h>
  22
  23 struct rc5t619_rtc {
  24         int                     irq;
  25         struct rtc_device       *rtc;
  26         struct rn5t618 *rn5t618;
  27 };
  28
  29 #define CTRL1_ALARM_ENABLED 0x40
  30 #define CTRL1_24HR 0x20
  31 #define CTRL1_PERIODIC_MASK 0xf
  32
  33 #define CTRL2_PON 0x10
  34 #define CTRL2_ALARM_STATUS 0x80
  35 #define CTRL2_CTFG 0x4
  36 #define CTRL2_CTC 0x1
  37
  38 #define MONTH_CENTFLAG 0x80
  39 #define HOUR_PMFLAG 0x20
  40 #define MDAY_DAL_EXT 0x80
  41
  42 static uint8_t rtc5t619_12hour_bcd2bin(uint8_t hour)
  43 {
  44         if (hour & HOUR_PMFLAG) {
  45                 hour = bcd2bin(hour & ~HOUR_PMFLAG);
  46                 return hour == 12 ? 12 : 12 + hour;
  47         }
  48
  49         hour = bcd2bin(hour);
  50         return hour == 12 ? 0 : hour;
  51 }
  52
  53 static uint8_t rtc5t619_12hour_bin2bcd(uint8_t hour)
  54 {
  55         if (!hour)
  56                 return 0x12;
  57
  58         if (hour < 12)
  59                 return bin2bcd(hour);
  60
  61         if (hour == 12)
  62                 return 0x12 | HOUR_PMFLAG;
  63
  64         return bin2bcd(hour - 12) | HOUR_PMFLAG;
  65 }
  66
  67 static int rc5t619_rtc_periodic_disable(struct device *dev)
  68 {
  69         struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
  70         int err;
  71
  72         /* disable function */
  73         err = regmap_update_bits(rtc->rn5t618->regmap,
  74                                  RN5T618_RTC_CTRL1, CTRL1_PERIODIC_MASK, 0);
  75         if (err < 0)
  76                 return err;
  77
  78         /* clear alarm flag and CTFG */
  79         err = regmap_update_bits(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2,
  80                                  CTRL2_ALARM_STATUS | CTRL2_CTFG | CTRL2_CTC,
  81                                  0);
  82         if (err < 0)
  83                 return err;
  84
  85         return 0;
  86 }
  87
  88 /* things to be done once after power on */
  89 static int rc5t619_rtc_pon_setup(struct device *dev)
  90 {
  91         struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
  92         int err;
  93         unsigned int reg_data;
  94
  95         err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &reg_data);
  96         if (err < 0)
  97                 return err;
  98
  99         /* clear VDET PON */
 100         reg_data &= ~(CTRL2_PON | CTRL2_CTC | 0x4a);    /* 0101-1011 */
 101         reg_data |= 0x20;       /* 0010-0000 */
 102         err = regmap_write(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, reg_data);
 103         if (err < 0)
 104                 return err;
 105
 106         /* clearing RTC Adjust register */
 107         err = regmap_write(rtc->rn5t618->regmap, RN5T618_RTC_ADJUST, 0);
 108         if (err)
 109                 return err;
 110
 111         return regmap_update_bits(rtc->rn5t618->regmap,
 112                                         RN5T618_RTC_CTRL1,
 113                                         CTRL1_24HR, CTRL1_24HR);
 114 }
 115
 116 static int rc5t619_rtc_read_time(struct device *dev, struct rtc_time *tm)
 117 {
 118         struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 119         u8 buff[7];
 120         int err;
 121         int cent_flag;
 122         unsigned int ctrl1;
 123         unsigned int ctrl2;
 124
 125         err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &ctrl2);
 126         if (err < 0)
 127                 return err;
 128
 129         if (ctrl2 & CTRL2_PON)
 130                 return -EINVAL;
 131
 132         err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
 133         if (err < 0)
 134                 return err;
 135
 136         err = regmap_bulk_read(rtc->rn5t618->regmap, RN5T618_RTC_SECONDS,
 137                                buff, sizeof(buff));
 138         if (err < 0)
 139                 return err;
 140
 141         if (buff[5] & MONTH_CENTFLAG)
 142                 cent_flag = 1;
 143         else
 144                 cent_flag = 0;
 145
 146         tm->tm_sec  = bcd2bin(buff[0]);
 147         tm->tm_min  = bcd2bin(buff[1]);
 148
 149         if (ctrl1 & CTRL1_24HR)
 150                 tm->tm_hour = bcd2bin(buff[2]);
 151         else
 152                 tm->tm_hour = rtc5t619_12hour_bcd2bin(buff[2]);
 153
 154         tm->tm_wday = bcd2bin(buff[3]);
 155         tm->tm_mday = bcd2bin(buff[4]);
 156         tm->tm_mon  = bcd2bin(buff[5] & 0x1f) - 1; /* back to system 0-11 */
 157         tm->tm_year = bcd2bin(buff[6]) + 100 * cent_flag;
 158
 159         return 0;
 160 }
 161
 162 static int rc5t619_rtc_set_time(struct device *dev, struct rtc_time *tm)
 163 {
 164         struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 165         u8 buff[7];
 166         int err;
 167         int cent_flag;
 168         unsigned int ctrl1;
 169         unsigned int ctrl2;
 170
 171         err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &ctrl2);
 172         if (err < 0)
 173                 return err;
 174
 175         if (ctrl2 & CTRL2_PON)
 176                 rc5t619_rtc_pon_setup(dev);
 177
 178         err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
 179         if (err < 0)
 180                 return err;
 181
 182         if (tm->tm_year >= 100)
 183                 cent_flag = 1;
 184         else
 185                 cent_flag = 0;
 186
 187         buff[0] = bin2bcd(tm->tm_sec);
 188         buff[1] = bin2bcd(tm->tm_min);
 189
 190         if (ctrl1 & CTRL1_24HR)
 191                 buff[2] = bin2bcd(tm->tm_hour);
 192         else
 193                 buff[2] = rtc5t619_12hour_bin2bcd(tm->tm_hour);
 194
 195         buff[3] = bin2bcd(tm->tm_wday);
 196         buff[4] = bin2bcd(tm->tm_mday);
 197         buff[5] = bin2bcd(tm->tm_mon + 1);      /* system set 0-11 */
 198         buff[6] = bin2bcd(tm->tm_year - cent_flag * 100);
 199
 200         if (cent_flag)
 201                 buff[5] |= MONTH_CENTFLAG;
 202
 203         err = regmap_bulk_write(rtc->rn5t618->regmap, RN5T618_RTC_SECONDS,
 204                                 buff, sizeof(buff));
 205         if (err < 0) {
 206                 dev_err(dev, "failed to program new time: %d\n", err);
 207                 return err;
 208         }
 209
 210         return 0;
 211 }
 212
 213 /* 0-disable, 1-enable */
 214 static int rc5t619_rtc_alarm_enable(struct device *dev, unsigned int enabled)
 215 {
 216         struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 217
 218         return regmap_update_bits(rtc->rn5t618->regmap,
 219                         RN5T618_RTC_CTRL1,
 220                         CTRL1_ALARM_ENABLED,
 221                         enabled ? CTRL1_ALARM_ENABLED : 0);
 222 }
 223
 224 static int rc5t619_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 225 {
 226         struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 227         u8 buff[6];
 228         unsigned int buff_cent;
 229         int err;
 230         int cent_flag;
 231         unsigned int ctrl1;
 232
 233         err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
 234         if (err)
 235                 return err;
 236
 237         err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_MONTH, &buff_cent);
 238         if (err < 0) {
 239                 dev_err(dev, "failed to read time: %d\n", err);
 240                 return err;
 241         }
 242
 243         if (buff_cent & MONTH_CENTFLAG)
 244                 cent_flag = 1;
 245         else
 246                 cent_flag = 0;
 247
 248         err = regmap_bulk_read(rtc->rn5t618->regmap, RN5T618_RTC_ALARM_Y_SEC,
 249                                buff, sizeof(buff));
 250         if (err)
 251                 return err;
 252
 253         buff[3] = buff[3] & 0x3f;
 254
 255         alrm->time.tm_sec  = bcd2bin(buff[0]);
 256         alrm->time.tm_min  = bcd2bin(buff[1]);
 257
 258         if (ctrl1 & CTRL1_24HR)
 259                 alrm->time.tm_hour = bcd2bin(buff[2]);
 260         else
 261                 alrm->time.tm_hour = rtc5t619_12hour_bcd2bin(buff[2]);
 262
 263         alrm->time.tm_mday = bcd2bin(buff[3]);
 264         alrm->time.tm_mon  = bcd2bin(buff[4]) - 1;
 265         alrm->time.tm_year = bcd2bin(buff[5]) + 100 * cent_flag;
 266         alrm->enabled = !!(ctrl1 & CTRL1_ALARM_ENABLED);
 267         dev_dbg(dev, "read alarm: %ptR\n", &alrm->time);
 268
 269         return 0;
 270 }
 271
 272 static int rc5t619_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 273 {
 274         struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 275         u8 buff[6];
 276         int err;
 277         int cent_flag;
 278         unsigned int ctrl1;
 279
 280         err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL1, &ctrl1);
 281         if (err)
 282                 return err;
 283
 284         err = rc5t619_rtc_alarm_enable(dev, 0);
 285         if (err < 0)
 286                 return err;
 287
 288         if (rtc->irq == -1)
 289                 return -EINVAL;
 290
 291         if (alrm->enabled == 0)
 292                 return 0;
 293
 294         if (alrm->time.tm_year >= 100)
 295                 cent_flag = 1;
 296         else
 297                 cent_flag = 0;
 298
 299         alrm->time.tm_mon += 1;
 300         buff[0] = bin2bcd(alrm->time.tm_sec);
 301         buff[1] = bin2bcd(alrm->time.tm_min);
 302
 303         if (ctrl1 & CTRL1_24HR)
 304                 buff[2] = bin2bcd(alrm->time.tm_hour);
 305         else
 306                 buff[2] = rtc5t619_12hour_bin2bcd(alrm->time.tm_hour);
 307
 308         buff[3] = bin2bcd(alrm->time.tm_mday);
 309         buff[4] = bin2bcd(alrm->time.tm_mon);
 310         buff[5] = bin2bcd(alrm->time.tm_year - 100 * cent_flag);
 311         buff[3] |= MDAY_DAL_EXT;
 312
 313         err = regmap_bulk_write(rtc->rn5t618->regmap, RN5T618_RTC_ALARM_Y_SEC,
 314                                 buff, sizeof(buff));
 315         if (err < 0)
 316                 return err;
 317
 318         return rc5t619_rtc_alarm_enable(dev, alrm->enabled);
 319 }
 320
 321 static const struct rtc_class_ops rc5t619_rtc_ops = {
 322         .read_time      = rc5t619_rtc_read_time,
 323         .set_time       = rc5t619_rtc_set_time,
 324         .set_alarm      = rc5t619_rtc_set_alarm,
 325         .read_alarm     = rc5t619_rtc_read_alarm,
 326         .alarm_irq_enable = rc5t619_rtc_alarm_enable,
 327 };
 328
 329 static int rc5t619_rtc_alarm_flag_clr(struct device *dev)
 330 {
 331         struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 332
 333         /* clear alarm-D status bits.*/
 334         return regmap_update_bits(rtc->rn5t618->regmap,
 335                                 RN5T618_RTC_CTRL2,
 336                                 CTRL2_ALARM_STATUS | CTRL2_CTC, 0);
 337 }
 338
 339 static irqreturn_t rc5t619_rtc_irq(int irq, void *data)
 340 {
 341         struct device *dev = data;
 342         struct rc5t619_rtc *rtc = dev_get_drvdata(dev);
 343
 344         rc5t619_rtc_alarm_flag_clr(dev);
 345
 346         rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
 347         return IRQ_HANDLED;
 348 }
 349
 350 static int rc5t619_rtc_probe(struct platform_device *pdev)
 351 {
 352         struct device *dev = &pdev->dev;
 353         struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
 354         struct rc5t619_rtc *rtc;
 355         unsigned int ctrl2;
 356         int err;
 357
 358         rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL);
 359         if (!rtc)
 360                 return -ENOMEM;
 361
 362         rtc->rn5t618 = rn5t618;
 363
 364         dev_set_drvdata(dev, rtc);
 365         rtc->irq = -1;
 366
 367         if (rn5t618->irq_data)
 368                 rtc->irq = regmap_irq_get_virq(rn5t618->irq_data,
 369                                                RN5T618_IRQ_RTC);
 370
 371         if (rtc->irq  < 0)
 372                 rtc->irq = -1;
 373
 374         err = regmap_read(rtc->rn5t618->regmap, RN5T618_RTC_CTRL2, &ctrl2);
 375         if (err < 0)
 376                 return err;
 377
 378         /* disable rtc periodic function */
 379         err = rc5t619_rtc_periodic_disable(&pdev->dev);
 380         if (err)
 381                 return err;
 382
 383         if (ctrl2 & CTRL2_PON) {
 384                 err = rc5t619_rtc_alarm_flag_clr(&pdev->dev);
 385                 if (err)
 386                         return err;
 387         }
 388
 389         rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
 390         if (IS_ERR(rtc->rtc)) {
 391                 err = PTR_ERR(rtc->rtc);
 392                 dev_err(dev, "RTC device register: err %d\n", err);
 393                 return err;
 394         }
 395
 396         rtc->rtc->ops = &rc5t619_rtc_ops;
 397         rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_1900;
 398         rtc->rtc->range_max = RTC_TIMESTAMP_END_2099;
 399
 400         /* set interrupt and enable it */
 401         if (rtc->irq != -1) {
 402                 err = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
 403                                                 rc5t619_rtc_irq,
 404                                                 IRQF_ONESHOT,
 405                                                 "rtc-rc5t619",
 406                                                 &pdev->dev);
 407                 if (err < 0) {
 408                         dev_err(&pdev->dev, "request IRQ:%d fail\n", rtc->irq);
 409                         rtc->irq = -1;
 410
 411                         err = rc5t619_rtc_alarm_enable(&pdev->dev, 0);
 412                         if (err)
 413                                 return err;
 414
 415                 } else {
 416                         /* enable wake */
 417                         device_init_wakeup(&pdev->dev, 1);
 418                         enable_irq_wake(rtc->irq);
 419                 }
 420         } else {
 421                 /* system don't want to using alarm interrupt, so close it */
 422                 err = rc5t619_rtc_alarm_enable(&pdev->dev, 0);
 423                 if (err)
 424                         return err;
 425
 426                 dev_warn(&pdev->dev, "rc5t619 interrupt is disabled\n");
 427         }
 428
 429         return devm_rtc_register_device(rtc->rtc);
 430 }
 431
 432 static struct platform_driver rc5t619_rtc_driver = {
 433         .driver = {
 434                 .name   = "rc5t619-rtc",
 435         },
 436         .probe  = rc5t619_rtc_probe,
 437 };
 438
 439 module_platform_driver(rc5t619_rtc_driver);
 440 MODULE_ALIAS("platform:rc5t619-rtc");
 441 MODULE_DESCRIPTION("RICOH RC5T619 RTC driver");
 442 MODULE_LICENSE("GPL");