drivers/rtc/rtc-pcf2127.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * An I2C and SPI driver for the NXP PCF2127/29 RTC
   4  * Copyright 2013 Til-Technologies
   5  *
   6  * Author: Renaud Cerrato <r.cerrato@til-technologies.fr>
   7  *
   8  * Watchdog and tamper functions
   9  * Author: Bruno Thomsen <bruno.thomsen@gmail.com>
  10  *
  11  * based on the other drivers in this same directory.
  12  *
  13  * Datasheet: http://cache.nxp.com/documents/data_sheet/PCF2127.pdf
  14  */
  15
  16 #include <linux/i2c.h>
  17 #include <linux/spi/spi.h>
  18 #include <linux/bcd.h>
  19 #include <linux/rtc.h>
  20 #include <linux/slab.h>
  21 #include <linux/module.h>
  22 #include <linux/of.h>
  23 #include <linux/of_irq.h>
  24 #include <linux/regmap.h>
  25 #include <linux/watchdog.h>
  26
  27 /* Control register 1 */
  28 #define PCF2127_REG_CTRL1               0x00
  29 #define PCF2127_BIT_CTRL1_TSF1                  BIT(4)
  30 /* Control register 2 */
  31 #define PCF2127_REG_CTRL2               0x01
  32 #define PCF2127_BIT_CTRL2_AIE                   BIT(1)
  33 #define PCF2127_BIT_CTRL2_TSIE                  BIT(2)
  34 #define PCF2127_BIT_CTRL2_AF                    BIT(4)
  35 #define PCF2127_BIT_CTRL2_TSF2                  BIT(5)
  36 #define PCF2127_BIT_CTRL2_WDTF                  BIT(6)
  37 /* Control register 3 */
  38 #define PCF2127_REG_CTRL3               0x02
  39 #define PCF2127_BIT_CTRL3_BLIE                  BIT(0)
  40 #define PCF2127_BIT_CTRL3_BIE                   BIT(1)
  41 #define PCF2127_BIT_CTRL3_BLF                   BIT(2)
  42 #define PCF2127_BIT_CTRL3_BF                    BIT(3)
  43 #define PCF2127_BIT_CTRL3_BTSE                  BIT(4)
  44 /* Time and date registers */
  45 #define PCF2127_REG_SC                  0x03
  46 #define PCF2127_BIT_SC_OSF                      BIT(7)
  47 #define PCF2127_REG_MN                  0x04
  48 #define PCF2127_REG_HR                  0x05
  49 #define PCF2127_REG_DM                  0x06
  50 #define PCF2127_REG_DW                  0x07
  51 #define PCF2127_REG_MO                  0x08
  52 #define PCF2127_REG_YR                  0x09
  53 /* Alarm registers */
  54 #define PCF2127_REG_ALARM_SC            0x0A
  55 #define PCF2127_REG_ALARM_MN            0x0B
  56 #define PCF2127_REG_ALARM_HR            0x0C
  57 #define PCF2127_REG_ALARM_DM            0x0D
  58 #define PCF2127_REG_ALARM_DW            0x0E
  59 #define PCF2127_BIT_ALARM_AE                    BIT(7)
  60 /* Watchdog registers */
  61 #define PCF2127_REG_WD_CTL              0x10
  62 #define PCF2127_BIT_WD_CTL_TF0                  BIT(0)
  63 #define PCF2127_BIT_WD_CTL_TF1                  BIT(1)
  64 #define PCF2127_BIT_WD_CTL_CD0                  BIT(6)
  65 #define PCF2127_BIT_WD_CTL_CD1                  BIT(7)
  66 #define PCF2127_REG_WD_VAL              0x11
  67 /* Tamper timestamp registers */
  68 #define PCF2127_REG_TS_CTRL             0x12
  69 #define PCF2127_BIT_TS_CTRL_TSOFF               BIT(6)
  70 #define PCF2127_BIT_TS_CTRL_TSM                 BIT(7)
  71 #define PCF2127_REG_TS_SC               0x13
  72 #define PCF2127_REG_TS_MN               0x14
  73 #define PCF2127_REG_TS_HR               0x15
  74 #define PCF2127_REG_TS_DM               0x16
  75 #define PCF2127_REG_TS_MO               0x17
  76 #define PCF2127_REG_TS_YR               0x18
  77 /*
  78  * RAM registers
  79  * PCF2127 has 512 bytes general-purpose static RAM (SRAM) that is
  80  * battery backed and can survive a power outage.
  81  * PCF2129 doesn't have this feature.
  82  */
  83 #define PCF2127_REG_RAM_ADDR_MSB        0x1A
  84 #define PCF2127_REG_RAM_WRT_CMD         0x1C
  85 #define PCF2127_REG_RAM_RD_CMD          0x1D
  86
  87 /* Watchdog timer value constants */
  88 #define PCF2127_WD_VAL_STOP             0
  89 #define PCF2127_WD_VAL_MIN              2
  90 #define PCF2127_WD_VAL_MAX              255
  91 #define PCF2127_WD_VAL_DEFAULT          60
  92
  93 struct pcf2127 {
  94         struct rtc_device *rtc;
  95         struct watchdog_device wdd;
  96         struct regmap *regmap;
  97 };
  98
  99 /*
 100  * In the routines that deal directly with the pcf2127 hardware, we use
 101  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
 102  */
 103 static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm)
 104 {
 105         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
 106         unsigned char buf[10];
 107         int ret;
 108
 109         /*
 110          * Avoid reading CTRL2 register as it causes WD_VAL register
 111          * value to reset to 0 which means watchdog is stopped.
 112          */
 113         ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_CTRL3,
 114                                (buf + PCF2127_REG_CTRL3),
 115                                ARRAY_SIZE(buf) - PCF2127_REG_CTRL3);
 116         if (ret) {
 117                 dev_err(dev, "%s: read error\n", __func__);
 118                 return ret;
 119         }
 120
 121         if (buf[PCF2127_REG_CTRL3] & PCF2127_BIT_CTRL3_BLF)
 122                 dev_info(dev,
 123                         "low voltage detected, check/replace RTC battery.\n");
 124
 125         /* Clock integrity is not guaranteed when OSF flag is set. */
 126         if (buf[PCF2127_REG_SC] & PCF2127_BIT_SC_OSF) {
 127                 /*
 128                  * no need clear the flag here,
 129                  * it will be cleared once the new date is saved
 130                  */
 131                 dev_warn(dev,
 132                          "oscillator stop detected, date/time is not reliable\n");
 133                 return -EINVAL;
 134         }
 135
 136         dev_dbg(dev,
 137                 "%s: raw data is cr3=%02x, sec=%02x, min=%02x, hr=%02x, "
 138                 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
 139                 __func__, buf[PCF2127_REG_CTRL3], buf[PCF2127_REG_SC],
 140                 buf[PCF2127_REG_MN], buf[PCF2127_REG_HR],
 141                 buf[PCF2127_REG_DM], buf[PCF2127_REG_DW],
 142                 buf[PCF2127_REG_MO], buf[PCF2127_REG_YR]);
 143
 144         tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F);
 145         tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F);
 146         tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */
 147         tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F);
 148         tm->tm_wday = buf[PCF2127_REG_DW] & 0x07;
 149         tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
 150         tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]);
 151         tm->tm_year += 100;
 152
 153         dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 154                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 155                 __func__,
 156                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 157                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 158
 159         return 0;
 160 }
 161
 162 static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
 163 {
 164         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
 165         unsigned char buf[7];
 166         int i = 0, err;
 167
 168         dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "
 169                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 170                 __func__,
 171                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 172                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 173
 174         /* hours, minutes and seconds */
 175         buf[i++] = bin2bcd(tm->tm_sec); /* this will also clear OSF flag */
 176         buf[i++] = bin2bcd(tm->tm_min);
 177         buf[i++] = bin2bcd(tm->tm_hour);
 178         buf[i++] = bin2bcd(tm->tm_mday);
 179         buf[i++] = tm->tm_wday & 0x07;
 180
 181         /* month, 1 - 12 */
 182         buf[i++] = bin2bcd(tm->tm_mon + 1);
 183
 184         /* year */
 185         buf[i++] = bin2bcd(tm->tm_year - 100);
 186
 187         /* write register's data */
 188         err = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_SC, buf, i);
 189         if (err) {
 190                 dev_err(dev,
 191                         "%s: err=%d", __func__, err);
 192                 return err;
 193         }
 194
 195         return 0;
 196 }
 197
 198 static int pcf2127_rtc_ioctl(struct device *dev,
 199                                 unsigned int cmd, unsigned long arg)
 200 {
 201         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
 202         int val, touser = 0;
 203         int ret;
 204
 205         switch (cmd) {
 206         case RTC_VL_READ:
 207                 ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &val);
 208                 if (ret)
 209                         return ret;
 210
 211                 if (val & PCF2127_BIT_CTRL3_BLF)
 212                         touser |= RTC_VL_BACKUP_LOW;
 213
 214                 if (val & PCF2127_BIT_CTRL3_BF)
 215                         touser |= RTC_VL_BACKUP_SWITCH;
 216
 217                 return put_user(touser, (unsigned int __user *)arg);
 218
 219         case RTC_VL_CLR:
 220                 return regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL3,
 221                                           PCF2127_BIT_CTRL3_BF, 0);
 222
 223         default:
 224                 return -ENOIOCTLCMD;
 225         }
 226 }
 227
 228 static const struct rtc_class_ops pcf2127_rtc_ops = {
 229         .ioctl          = pcf2127_rtc_ioctl,
 230         .read_time      = pcf2127_rtc_read_time,
 231         .set_time       = pcf2127_rtc_set_time,
 232 };
 233
 234 static int pcf2127_nvmem_read(void *priv, unsigned int offset,
 235                               void *val, size_t bytes)
 236 {
 237         struct pcf2127 *pcf2127 = priv;
 238         int ret;
 239         unsigned char offsetbuf[] = { offset >> 8, offset };
 240
 241         ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_ADDR_MSB,
 242                                 offsetbuf, 2);
 243         if (ret)
 244                 return ret;
 245
 246         return regmap_bulk_read(pcf2127->regmap, PCF2127_REG_RAM_RD_CMD,
 247                                 val, bytes);
 248 }
 249
 250 static int pcf2127_nvmem_write(void *priv, unsigned int offset,
 251                                void *val, size_t bytes)
 252 {
 253         struct pcf2127 *pcf2127 = priv;
 254         int ret;
 255         unsigned char offsetbuf[] = { offset >> 8, offset };
 256
 257         ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_ADDR_MSB,
 258                                 offsetbuf, 2);
 259         if (ret)
 260                 return ret;
 261
 262         return regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_WRT_CMD,
 263                                  val, bytes);
 264 }
 265
 266 /* watchdog driver */
 267
 268 static int pcf2127_wdt_ping(struct watchdog_device *wdd)
 269 {
 270         struct pcf2127 *pcf2127 = watchdog_get_drvdata(wdd);
 271
 272         return regmap_write(pcf2127->regmap, PCF2127_REG_WD_VAL, wdd->timeout);
 273 }
 274
 275 /*
 276  * Restart watchdog timer if feature is active.
 277  *
 278  * Note: Reading CTRL2 register causes watchdog to stop which is unfortunate,
 279  * since register also contain control/status flags for other features.
 280  * Always call this function after reading CTRL2 register.
 281  */
 282 static int pcf2127_wdt_active_ping(struct watchdog_device *wdd)
 283 {
 284         int ret = 0;
 285
 286         if (watchdog_active(wdd)) {
 287                 ret = pcf2127_wdt_ping(wdd);
 288                 if (ret)
 289                         dev_err(wdd->parent,
 290                                 "%s: watchdog restart failed, ret=%d\n",
 291                                 __func__, ret);
 292         }
 293
 294         return ret;
 295 }
 296
 297 static int pcf2127_wdt_start(struct watchdog_device *wdd)
 298 {
 299         return pcf2127_wdt_ping(wdd);
 300 }
 301
 302 static int pcf2127_wdt_stop(struct watchdog_device *wdd)
 303 {
 304         struct pcf2127 *pcf2127 = watchdog_get_drvdata(wdd);
 305
 306         return regmap_write(pcf2127->regmap, PCF2127_REG_WD_VAL,
 307                             PCF2127_WD_VAL_STOP);
 308 }
 309
 310 static int pcf2127_wdt_set_timeout(struct watchdog_device *wdd,
 311                                    unsigned int new_timeout)
 312 {
 313         dev_dbg(wdd->parent, "new watchdog timeout: %is (old: %is)\n",
 314                 new_timeout, wdd->timeout);
 315
 316         wdd->timeout = new_timeout;
 317
 318         return pcf2127_wdt_active_ping(wdd);
 319 }
 320
 321 static const struct watchdog_info pcf2127_wdt_info = {
 322         .identity = "NXP PCF2127/PCF2129 Watchdog",
 323         .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
 324 };
 325
 326 static const struct watchdog_ops pcf2127_watchdog_ops = {
 327         .owner = THIS_MODULE,
 328         .start = pcf2127_wdt_start,
 329         .stop = pcf2127_wdt_stop,
 330         .ping = pcf2127_wdt_ping,
 331         .set_timeout = pcf2127_wdt_set_timeout,
 332 };
 333
 334 static int pcf2127_watchdog_init(struct device *dev, struct pcf2127 *pcf2127)
 335 {
 336         u32 wdd_timeout;
 337         int ret;
 338
 339         if (!IS_ENABLED(CONFIG_WATCHDOG) ||
 340             !device_property_read_bool(dev, "reset-source"))
 341                 return 0;
 342
 343         pcf2127->wdd.parent = dev;
 344         pcf2127->wdd.info = &pcf2127_wdt_info;
 345         pcf2127->wdd.ops = &pcf2127_watchdog_ops;
 346         pcf2127->wdd.min_timeout = PCF2127_WD_VAL_MIN;
 347         pcf2127->wdd.max_timeout = PCF2127_WD_VAL_MAX;
 348         pcf2127->wdd.timeout = PCF2127_WD_VAL_DEFAULT;
 349         pcf2127->wdd.min_hw_heartbeat_ms = 500;
 350         pcf2127->wdd.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
 351
 352         watchdog_set_drvdata(&pcf2127->wdd, pcf2127);
 353
 354         /* Test if watchdog timer is started by bootloader */
 355         ret = regmap_read(pcf2127->regmap, PCF2127_REG_WD_VAL, &wdd_timeout);
 356         if (ret)
 357                 return ret;
 358
 359         if (wdd_timeout)
 360                 set_bit(WDOG_HW_RUNNING, &pcf2127->wdd.status);
 361
 362         return devm_watchdog_register_device(dev, &pcf2127->wdd);
 363 }
 364
 365 /* Alarm */
 366 static int pcf2127_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 367 {
 368         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
 369         unsigned int buf[5], ctrl2;
 370         int ret;
 371
 372         ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL2, &ctrl2);
 373         if (ret)
 374                 return ret;
 375
 376         ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
 377         if (ret)
 378                 return ret;
 379
 380         ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_ALARM_SC, buf,
 381                                sizeof(buf));
 382         if (ret)
 383                 return ret;
 384
 385         alrm->enabled = ctrl2 & PCF2127_BIT_CTRL2_AIE;
 386         alrm->pending = ctrl2 & PCF2127_BIT_CTRL2_AF;
 387
 388         alrm->time.tm_sec = bcd2bin(buf[0] & 0x7F);
 389         alrm->time.tm_min = bcd2bin(buf[1] & 0x7F);
 390         alrm->time.tm_hour = bcd2bin(buf[2] & 0x3F);
 391         alrm->time.tm_mday = bcd2bin(buf[3] & 0x3F);
 392
 393         return 0;
 394 }
 395
 396 static int pcf2127_rtc_alarm_irq_enable(struct device *dev, u32 enable)
 397 {
 398         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
 399         int ret;
 400
 401         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
 402                                  PCF2127_BIT_CTRL2_AIE,
 403                                  enable ? PCF2127_BIT_CTRL2_AIE : 0);
 404         if (ret)
 405                 return ret;
 406
 407         return pcf2127_wdt_active_ping(&pcf2127->wdd);
 408 }
 409
 410 static int pcf2127_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 411 {
 412         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
 413         uint8_t buf[5];
 414         int ret;
 415
 416         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
 417                                  PCF2127_BIT_CTRL2_AF, 0);
 418         if (ret)
 419                 return ret;
 420
 421         ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
 422         if (ret)
 423                 return ret;
 424
 425         buf[0] = bin2bcd(alrm->time.tm_sec);
 426         buf[1] = bin2bcd(alrm->time.tm_min);
 427         buf[2] = bin2bcd(alrm->time.tm_hour);
 428         buf[3] = bin2bcd(alrm->time.tm_mday);
 429         buf[4] = PCF2127_BIT_ALARM_AE; /* Do not match on week day */
 430
 431         ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_ALARM_SC, buf,
 432                                 sizeof(buf));
 433         if (ret)
 434                 return ret;
 435
 436         return pcf2127_rtc_alarm_irq_enable(dev, alrm->enabled);
 437 }
 438
 439 static irqreturn_t pcf2127_rtc_irq(int irq, void *dev)
 440 {
 441         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
 442         unsigned int ctrl2 = 0;
 443         int ret = 0;
 444
 445         ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL2, &ctrl2);
 446         if (ret)
 447                 return IRQ_NONE;
 448
 449         if (!(ctrl2 & PCF2127_BIT_CTRL2_AF))
 450                 return IRQ_NONE;
 451
 452         regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
 453                      ctrl2 & ~(PCF2127_BIT_CTRL2_AF | PCF2127_BIT_CTRL2_WDTF));
 454
 455         rtc_update_irq(pcf2127->rtc, 1, RTC_IRQF | RTC_AF);
 456
 457         pcf2127_wdt_active_ping(&pcf2127->wdd);
 458
 459         return IRQ_HANDLED;
 460 }
 461
 462 static const struct rtc_class_ops pcf2127_rtc_alrm_ops = {
 463         .ioctl            = pcf2127_rtc_ioctl,
 464         .read_time        = pcf2127_rtc_read_time,
 465         .set_time         = pcf2127_rtc_set_time,
 466         .read_alarm       = pcf2127_rtc_read_alarm,
 467         .set_alarm        = pcf2127_rtc_set_alarm,
 468         .alarm_irq_enable = pcf2127_rtc_alarm_irq_enable,
 469 };
 470
 471 /* sysfs interface */
 472
 473 static ssize_t timestamp0_store(struct device *dev,
 474                                 struct device_attribute *attr,
 475                                 const char *buf, size_t count)
 476 {
 477         struct pcf2127 *pcf2127 = dev_get_drvdata(dev->parent);
 478         int ret;
 479
 480         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL1,
 481                                  PCF2127_BIT_CTRL1_TSF1, 0);
 482         if (ret) {
 483                 dev_err(dev, "%s: update ctrl1 ret=%d\n", __func__, ret);
 484                 return ret;
 485         }
 486
 487         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
 488                                  PCF2127_BIT_CTRL2_TSF2, 0);
 489         if (ret) {
 490                 dev_err(dev, "%s: update ctrl2 ret=%d\n", __func__, ret);
 491                 return ret;
 492         }
 493
 494         ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
 495         if (ret)
 496                 return ret;
 497
 498         return count;
 499 };
 500
 501 static ssize_t timestamp0_show(struct device *dev,
 502                                struct device_attribute *attr, char *buf)
 503 {
 504         struct pcf2127 *pcf2127 = dev_get_drvdata(dev->parent);
 505         struct rtc_time tm;
 506         int ret;
 507         unsigned char data[25];
 508
 509         ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_CTRL1, data,
 510                                sizeof(data));
 511         if (ret) {
 512                 dev_err(dev, "%s: read error ret=%d\n", __func__, ret);
 513                 return ret;
 514         }
 515
 516         dev_dbg(dev,
 517                 "%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, ts_sc=%02x, "
 518                 "ts_mn=%02x, ts_hr=%02x, ts_dm=%02x, ts_mo=%02x, ts_yr=%02x\n",
 519                 __func__, data[PCF2127_REG_CTRL1], data[PCF2127_REG_CTRL2],
 520                 data[PCF2127_REG_CTRL3], data[PCF2127_REG_TS_SC],
 521                 data[PCF2127_REG_TS_MN], data[PCF2127_REG_TS_HR],
 522                 data[PCF2127_REG_TS_DM], data[PCF2127_REG_TS_MO],
 523                 data[PCF2127_REG_TS_YR]);
 524
 525         ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
 526         if (ret)
 527                 return ret;
 528
 529         if (!(data[PCF2127_REG_CTRL1] & PCF2127_BIT_CTRL1_TSF1) &&
 530             !(data[PCF2127_REG_CTRL2] & PCF2127_BIT_CTRL2_TSF2))
 531                 return 0;
 532
 533         tm.tm_sec = bcd2bin(data[PCF2127_REG_TS_SC] & 0x7F);
 534         tm.tm_min = bcd2bin(data[PCF2127_REG_TS_MN] & 0x7F);
 535         tm.tm_hour = bcd2bin(data[PCF2127_REG_TS_HR] & 0x3F);
 536         tm.tm_mday = bcd2bin(data[PCF2127_REG_TS_DM] & 0x3F);
 537         /* TS_MO register (month) value range: 1-12 */
 538         tm.tm_mon = bcd2bin(data[PCF2127_REG_TS_MO] & 0x1F) - 1;
 539         tm.tm_year = bcd2bin(data[PCF2127_REG_TS_YR]);
 540         if (tm.tm_year < 70)
 541                 tm.tm_year += 100; /* assume we are in 1970...2069 */
 542
 543         ret = rtc_valid_tm(&tm);
 544         if (ret)
 545                 return ret;
 546
 547         return sprintf(buf, "%llu\n",
 548                        (unsigned long long)rtc_tm_to_time64(&tm));
 549 };
 550
 551 static DEVICE_ATTR_RW(timestamp0);
 552
 553 static struct attribute *pcf2127_attrs[] = {
 554         &dev_attr_timestamp0.attr,
 555         NULL
 556 };
 557
 558 static const struct attribute_group pcf2127_attr_group = {
 559         .attrs  = pcf2127_attrs,
 560 };
 561
 562 static int pcf2127_probe(struct device *dev, struct regmap *regmap,
 563                          int alarm_irq, const char *name, bool has_nvmem)
 564 {
 565         struct pcf2127 *pcf2127;
 566         int ret = 0;
 567
 568         dev_dbg(dev, "%s\n", __func__);
 569
 570         pcf2127 = devm_kzalloc(dev, sizeof(*pcf2127), GFP_KERNEL);
 571         if (!pcf2127)
 572                 return -ENOMEM;
 573
 574         pcf2127->regmap = regmap;
 575
 576         dev_set_drvdata(dev, pcf2127);
 577
 578         pcf2127->rtc = devm_rtc_allocate_device(dev);
 579         if (IS_ERR(pcf2127->rtc))
 580                 return PTR_ERR(pcf2127->rtc);
 581
 582         pcf2127->rtc->ops = &pcf2127_rtc_ops;
 583         pcf2127->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 584         pcf2127->rtc->range_max = RTC_TIMESTAMP_END_2099;
 585         pcf2127->rtc->set_start_time = true; /* Sets actual start to 1970 */
 586         pcf2127->rtc->uie_unsupported = 1;
 587
 588         if (alarm_irq > 0) {
 589                 ret = devm_request_threaded_irq(dev, alarm_irq, NULL,
 590                                                 pcf2127_rtc_irq,
 591                                                 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 592                                                 dev_name(dev), dev);
 593                 if (ret) {
 594                         dev_err(dev, "failed to request alarm irq\n");
 595                         return ret;
 596                 }
 597         }
 598
 599         if (alarm_irq > 0 || device_property_read_bool(dev, "wakeup-source")) {
 600                 device_init_wakeup(dev, true);
 601                 pcf2127->rtc->ops = &pcf2127_rtc_alrm_ops;
 602         }
 603
 604         if (has_nvmem) {
 605                 struct nvmem_config nvmem_cfg = {
 606                         .priv = pcf2127,
 607                         .reg_read = pcf2127_nvmem_read,
 608                         .reg_write = pcf2127_nvmem_write,
 609                         .size = 512,
 610                 };
 611
 612                 ret = devm_rtc_nvmem_register(pcf2127->rtc, &nvmem_cfg);
 613         }
 614
 615         /*
 616          * Watchdog timer enabled and reset pin /RST activated when timed out.
 617          * Select 1Hz clock source for watchdog timer.
 618          * Note: Countdown timer disabled and not available.
 619          */
 620         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_WD_CTL,
 621                                  PCF2127_BIT_WD_CTL_CD1 |
 622                                  PCF2127_BIT_WD_CTL_CD0 |
 623                                  PCF2127_BIT_WD_CTL_TF1 |
 624                                  PCF2127_BIT_WD_CTL_TF0,
 625                                  PCF2127_BIT_WD_CTL_CD1 |
 626                                  PCF2127_BIT_WD_CTL_CD0 |
 627                                  PCF2127_BIT_WD_CTL_TF1);
 628         if (ret) {
 629                 dev_err(dev, "%s: watchdog config (wd_ctl) failed\n", __func__);
 630                 return ret;
 631         }
 632
 633         pcf2127_watchdog_init(dev, pcf2127);
 634
 635         /*
 636          * Disable battery low/switch-over timestamp and interrupts.
 637          * Clear battery interrupt flags which can block new trigger events.
 638          * Note: This is the default chip behaviour but added to ensure
 639          * correct tamper timestamp and interrupt function.
 640          */
 641         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL3,
 642                                  PCF2127_BIT_CTRL3_BTSE |
 643                                  PCF2127_BIT_CTRL3_BIE |
 644                                  PCF2127_BIT_CTRL3_BLIE, 0);
 645         if (ret) {
 646                 dev_err(dev, "%s: interrupt config (ctrl3) failed\n",
 647                         __func__);
 648                 return ret;
 649         }
 650
 651         /*
 652          * Enable timestamp function and store timestamp of first trigger
 653          * event until TSF1 and TFS2 interrupt flags are cleared.
 654          */
 655         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_TS_CTRL,
 656                                  PCF2127_BIT_TS_CTRL_TSOFF |
 657                                  PCF2127_BIT_TS_CTRL_TSM,
 658                                  PCF2127_BIT_TS_CTRL_TSM);
 659         if (ret) {
 660                 dev_err(dev, "%s: tamper detection config (ts_ctrl) failed\n",
 661                         __func__);
 662                 return ret;
 663         }
 664
 665         /*
 666          * Enable interrupt generation when TSF1 or TSF2 timestamp flags
 667          * are set. Interrupt signal is an open-drain output and can be
 668          * left floating if unused.
 669          */
 670         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
 671                                  PCF2127_BIT_CTRL2_TSIE,
 672                                  PCF2127_BIT_CTRL2_TSIE);
 673         if (ret) {
 674                 dev_err(dev, "%s: tamper detection config (ctrl2) failed\n",
 675                         __func__);
 676                 return ret;
 677         }
 678
 679         ret = rtc_add_group(pcf2127->rtc, &pcf2127_attr_group);
 680         if (ret) {
 681                 dev_err(dev, "%s: tamper sysfs registering failed\n",
 682                         __func__);
 683                 return ret;
 684         }
 685
 686         return devm_rtc_register_device(pcf2127->rtc);
 687 }
 688
 689 #ifdef CONFIG_OF
 690 static const struct of_device_id pcf2127_of_match[] = {
 691         { .compatible = "nxp,pcf2127" },
 692         { .compatible = "nxp,pcf2129" },
 693         { .compatible = "nxp,pca2129" },
 694         {}
 695 };
 696 MODULE_DEVICE_TABLE(of, pcf2127_of_match);
 697 #endif
 698
 699 #if IS_ENABLED(CONFIG_I2C)
 700
 701 static int pcf2127_i2c_write(void *context, const void *data, size_t count)
 702 {
 703         struct device *dev = context;
 704         struct i2c_client *client = to_i2c_client(dev);
 705         int ret;
 706
 707         ret = i2c_master_send(client, data, count);
 708         if (ret != count)
 709                 return ret < 0 ? ret : -EIO;
 710
 711         return 0;
 712 }
 713
 714 static int pcf2127_i2c_gather_write(void *context,
 715                                 const void *reg, size_t reg_size,
 716                                 const void *val, size_t val_size)
 717 {
 718         struct device *dev = context;
 719         struct i2c_client *client = to_i2c_client(dev);
 720         int ret;
 721         void *buf;
 722
 723         if (WARN_ON(reg_size != 1))
 724                 return -EINVAL;
 725
 726         buf = kmalloc(val_size + 1, GFP_KERNEL);
 727         if (!buf)
 728                 return -ENOMEM;
 729
 730         memcpy(buf, reg, 1);
 731         memcpy(buf + 1, val, val_size);
 732
 733         ret = i2c_master_send(client, buf, val_size + 1);
 734
 735         kfree(buf);
 736
 737         if (ret != val_size + 1)
 738                 return ret < 0 ? ret : -EIO;
 739
 740         return 0;
 741 }
 742
 743 static int pcf2127_i2c_read(void *context, const void *reg, size_t reg_size,
 744                                 void *val, size_t val_size)
 745 {
 746         struct device *dev = context;
 747         struct i2c_client *client = to_i2c_client(dev);
 748         int ret;
 749
 750         if (WARN_ON(reg_size != 1))
 751                 return -EINVAL;
 752
 753         ret = i2c_master_send(client, reg, 1);
 754         if (ret != 1)
 755                 return ret < 0 ? ret : -EIO;
 756
 757         ret = i2c_master_recv(client, val, val_size);
 758         if (ret != val_size)
 759                 return ret < 0 ? ret : -EIO;
 760
 761         return 0;
 762 }
 763
 764 /*
 765  * The reason we need this custom regmap_bus instead of using regmap_init_i2c()
 766  * is that the STOP condition is required between set register address and
 767  * read register data when reading from registers.
 768  */
 769 static const struct regmap_bus pcf2127_i2c_regmap = {
 770         .write = pcf2127_i2c_write,
 771         .gather_write = pcf2127_i2c_gather_write,
 772         .read = pcf2127_i2c_read,
 773 };
 774
 775 static struct i2c_driver pcf2127_i2c_driver;
 776
 777 static int pcf2127_i2c_probe(struct i2c_client *client,
 778                                 const struct i2c_device_id *id)
 779 {
 780         struct regmap *regmap;
 781         static const struct regmap_config config = {
 782                 .reg_bits = 8,
 783                 .val_bits = 8,
 784                 .max_register = 0x1d,
 785         };
 786
 787         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 788                 return -ENODEV;
 789
 790         regmap = devm_regmap_init(&client->dev, &pcf2127_i2c_regmap,
 791                                         &client->dev, &config);
 792         if (IS_ERR(regmap)) {
 793                 dev_err(&client->dev, "%s: regmap allocation failed: %ld\n",
 794                         __func__, PTR_ERR(regmap));
 795                 return PTR_ERR(regmap);
 796         }
 797
 798         return pcf2127_probe(&client->dev, regmap, client->irq,
 799                              pcf2127_i2c_driver.driver.name, id->driver_data);
 800 }
 801
 802 static const struct i2c_device_id pcf2127_i2c_id[] = {
 803         { "pcf2127", 1 },
 804         { "pcf2129", 0 },
 805         { "pca2129", 0 },
 806         { }
 807 };
 808 MODULE_DEVICE_TABLE(i2c, pcf2127_i2c_id);
 809
 810 static struct i2c_driver pcf2127_i2c_driver = {
 811         .driver         = {
 812                 .name   = "rtc-pcf2127-i2c",
 813                 .of_match_table = of_match_ptr(pcf2127_of_match),
 814         },
 815         .probe          = pcf2127_i2c_probe,
 816         .id_table       = pcf2127_i2c_id,
 817 };
 818
 819 static int pcf2127_i2c_register_driver(void)
 820 {
 821         return i2c_add_driver(&pcf2127_i2c_driver);
 822 }
 823
 824 static void pcf2127_i2c_unregister_driver(void)
 825 {
 826         i2c_del_driver(&pcf2127_i2c_driver);
 827 }
 828
 829 #else
 830
 831 static int pcf2127_i2c_register_driver(void)
 832 {
 833         return 0;
 834 }
 835
 836 static void pcf2127_i2c_unregister_driver(void)
 837 {
 838 }
 839
 840 #endif
 841
 842 #if IS_ENABLED(CONFIG_SPI_MASTER)
 843
 844 static struct spi_driver pcf2127_spi_driver;
 845
 846 static int pcf2127_spi_probe(struct spi_device *spi)
 847 {
 848         static const struct regmap_config config = {
 849                 .reg_bits = 8,
 850                 .val_bits = 8,
 851                 .read_flag_mask = 0xa0,
 852                 .write_flag_mask = 0x20,
 853                 .max_register = 0x1d,
 854         };
 855         struct regmap *regmap;
 856
 857         regmap = devm_regmap_init_spi(spi, &config);
 858         if (IS_ERR(regmap)) {
 859                 dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
 860                         __func__, PTR_ERR(regmap));
 861                 return PTR_ERR(regmap);
 862         }
 863
 864         return pcf2127_probe(&spi->dev, regmap, spi->irq,
 865                              pcf2127_spi_driver.driver.name,
 866                              spi_get_device_id(spi)->driver_data);
 867 }
 868
 869 static const struct spi_device_id pcf2127_spi_id[] = {
 870         { "pcf2127", 1 },
 871         { "pcf2129", 0 },
 872         { "pca2129", 0 },
 873         { }
 874 };
 875 MODULE_DEVICE_TABLE(spi, pcf2127_spi_id);
 876
 877 static struct spi_driver pcf2127_spi_driver = {
 878         .driver         = {
 879                 .name   = "rtc-pcf2127-spi",
 880                 .of_match_table = of_match_ptr(pcf2127_of_match),
 881         },
 882         .probe          = pcf2127_spi_probe,
 883         .id_table       = pcf2127_spi_id,
 884 };
 885
 886 static int pcf2127_spi_register_driver(void)
 887 {
 888         return spi_register_driver(&pcf2127_spi_driver);
 889 }
 890
 891 static void pcf2127_spi_unregister_driver(void)
 892 {
 893         spi_unregister_driver(&pcf2127_spi_driver);
 894 }
 895
 896 #else
 897
 898 static int pcf2127_spi_register_driver(void)
 899 {
 900         return 0;
 901 }
 902
 903 static void pcf2127_spi_unregister_driver(void)
 904 {
 905 }
 906
 907 #endif
 908
 909 static int __init pcf2127_init(void)
 910 {
 911         int ret;
 912
 913         ret = pcf2127_i2c_register_driver();
 914         if (ret) {
 915                 pr_err("Failed to register pcf2127 i2c driver: %d\n", ret);
 916                 return ret;
 917         }
 918
 919         ret = pcf2127_spi_register_driver();
 920         if (ret) {
 921                 pr_err("Failed to register pcf2127 spi driver: %d\n", ret);
 922                 pcf2127_i2c_unregister_driver();
 923         }
 924
 925         return ret;
 926 }
 927 module_init(pcf2127_init)
 928
 929 static void __exit pcf2127_exit(void)
 930 {
 931         pcf2127_spi_unregister_driver();
 932         pcf2127_i2c_unregister_driver();
 933 }
 934 module_exit(pcf2127_exit)
 935
 936 MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
 937 MODULE_DESCRIPTION("NXP PCF2127/29 RTC driver");
 938 MODULE_LICENSE("GPL v2");