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