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 ? 1 : 0;
 203
 204                 if (copy_to_user((void __user *)arg, &touser, sizeof(int)))
 205                         return -EFAULT;
 206                 return 0;
 207         default:
 208                 return -ENOIOCTLCMD;
 209         }
 210 }
 211 #else
 212 #define pcf2127_rtc_ioctl NULL
 213 #endif
 214
 215 static const struct rtc_class_ops pcf2127_rtc_ops = {
 216         .ioctl          = pcf2127_rtc_ioctl,
 217         .read_time      = pcf2127_rtc_read_time,
 218         .set_time       = pcf2127_rtc_set_time,
 219 };
 220
 221 static int pcf2127_nvmem_read(void *priv, unsigned int offset,
 222                               void *val, size_t bytes)
 223 {
 224         struct pcf2127 *pcf2127 = priv;
 225         int ret;
 226         unsigned char offsetbuf[] = { offset >> 8, offset };
 227
 228         ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_ADDR_MSB,
 229                                 offsetbuf, 2);
 230         if (ret)
 231                 return ret;
 232
 233         return regmap_bulk_read(pcf2127->regmap, PCF2127_REG_RAM_RD_CMD,
 234                                 val, 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         return regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_WRT_CMD,
 250                                  val, bytes);
 251 }
 252
 253 /* watchdog driver */
 254
 255 static int pcf2127_wdt_ping(struct watchdog_device *wdd)
 256 {
 257         struct pcf2127 *pcf2127 = watchdog_get_drvdata(wdd);
 258
 259         return regmap_write(pcf2127->regmap, PCF2127_REG_WD_VAL, wdd->timeout);
 260 }
 261
 262 /*
 263  * Restart watchdog timer if feature is active.
 264  *
 265  * Note: Reading CTRL2 register causes watchdog to stop which is unfortunate,
 266  * since register also contain control/status flags for other features.
 267  * Always call this function after reading CTRL2 register.
 268  */
 269 static int pcf2127_wdt_active_ping(struct watchdog_device *wdd)
 270 {
 271         int ret = 0;
 272
 273         if (watchdog_active(wdd)) {
 274                 ret = pcf2127_wdt_ping(wdd);
 275                 if (ret)
 276                         dev_err(wdd->parent,
 277                                 "%s: watchdog restart failed, ret=%d\n",
 278                                 __func__, ret);
 279         }
 280
 281         return ret;
 282 }
 283
 284 static int pcf2127_wdt_start(struct watchdog_device *wdd)
 285 {
 286         return pcf2127_wdt_ping(wdd);
 287 }
 288
 289 static int pcf2127_wdt_stop(struct watchdog_device *wdd)
 290 {
 291         struct pcf2127 *pcf2127 = watchdog_get_drvdata(wdd);
 292
 293         return regmap_write(pcf2127->regmap, PCF2127_REG_WD_VAL,
 294                             PCF2127_WD_VAL_STOP);
 295 }
 296
 297 static int pcf2127_wdt_set_timeout(struct watchdog_device *wdd,
 298                                    unsigned int new_timeout)
 299 {
 300         dev_dbg(wdd->parent, "new watchdog timeout: %is (old: %is)\n",
 301                 new_timeout, wdd->timeout);
 302
 303         wdd->timeout = new_timeout;
 304
 305         return pcf2127_wdt_active_ping(wdd);
 306 }
 307
 308 static const struct watchdog_info pcf2127_wdt_info = {
 309         .identity = "NXP PCF2127/PCF2129 Watchdog",
 310         .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
 311 };
 312
 313 static const struct watchdog_ops pcf2127_watchdog_ops = {
 314         .owner = THIS_MODULE,
 315         .start = pcf2127_wdt_start,
 316         .stop = pcf2127_wdt_stop,
 317         .ping = pcf2127_wdt_ping,
 318         .set_timeout = pcf2127_wdt_set_timeout,
 319 };
 320
 321 /* sysfs interface */
 322
 323 static ssize_t timestamp0_store(struct device *dev,
 324                                 struct device_attribute *attr,
 325                                 const char *buf, size_t count)
 326 {
 327         struct pcf2127 *pcf2127 = dev_get_drvdata(dev->parent);
 328         int ret;
 329
 330         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL1,
 331                                  PCF2127_BIT_CTRL1_TSF1, 0);
 332         if (ret) {
 333                 dev_err(dev, "%s: update ctrl1 ret=%d\n", __func__, ret);
 334                 return ret;
 335         }
 336
 337         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
 338                                  PCF2127_BIT_CTRL2_TSF2, 0);
 339         if (ret) {
 340                 dev_err(dev, "%s: update ctrl2 ret=%d\n", __func__, ret);
 341                 return ret;
 342         }
 343
 344         ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
 345         if (ret)
 346                 return ret;
 347
 348         return count;
 349 };
 350
 351 static ssize_t timestamp0_show(struct device *dev,
 352                                struct device_attribute *attr, char *buf)
 353 {
 354         struct pcf2127 *pcf2127 = dev_get_drvdata(dev->parent);
 355         struct rtc_time tm;
 356         int ret;
 357         unsigned char data[25];
 358
 359         ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_CTRL1, data,
 360                                sizeof(data));
 361         if (ret) {
 362                 dev_err(dev, "%s: read error ret=%d\n", __func__, ret);
 363                 return ret;
 364         }
 365
 366         dev_dbg(dev,
 367                 "%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, ts_sc=%02x, "
 368                 "ts_mn=%02x, ts_hr=%02x, ts_dm=%02x, ts_mo=%02x, ts_yr=%02x\n",
 369                 __func__, data[PCF2127_REG_CTRL1], data[PCF2127_REG_CTRL2],
 370                 data[PCF2127_REG_CTRL3], data[PCF2127_REG_TS_SC],
 371                 data[PCF2127_REG_TS_MN], data[PCF2127_REG_TS_HR],
 372                 data[PCF2127_REG_TS_DM], data[PCF2127_REG_TS_MO],
 373                 data[PCF2127_REG_TS_YR]);
 374
 375         ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
 376         if (ret)
 377                 return ret;
 378
 379         if (!(data[PCF2127_REG_CTRL1] & PCF2127_BIT_CTRL1_TSF1) &&
 380             !(data[PCF2127_REG_CTRL2] & PCF2127_BIT_CTRL2_TSF2))
 381                 return 0;
 382
 383         tm.tm_sec = bcd2bin(data[PCF2127_REG_TS_SC] & 0x7F);
 384         tm.tm_min = bcd2bin(data[PCF2127_REG_TS_MN] & 0x7F);
 385         tm.tm_hour = bcd2bin(data[PCF2127_REG_TS_HR] & 0x3F);
 386         tm.tm_mday = bcd2bin(data[PCF2127_REG_TS_DM] & 0x3F);
 387         /* TS_MO register (month) value range: 1-12 */
 388         tm.tm_mon = bcd2bin(data[PCF2127_REG_TS_MO] & 0x1F) - 1;
 389         tm.tm_year = bcd2bin(data[PCF2127_REG_TS_YR]);
 390         if (tm.tm_year < 70)
 391                 tm.tm_year += 100; /* assume we are in 1970...2069 */
 392
 393         ret = rtc_valid_tm(&tm);
 394         if (ret)
 395                 return ret;
 396
 397         return sprintf(buf, "%llu\n",
 398                        (unsigned long long)rtc_tm_to_time64(&tm));
 399 };
 400
 401 static DEVICE_ATTR_RW(timestamp0);
 402
 403 static struct attribute *pcf2127_attrs[] = {
 404         &dev_attr_timestamp0.attr,
 405         NULL
 406 };
 407
 408 static const struct attribute_group pcf2127_attr_group = {
 409         .attrs  = pcf2127_attrs,
 410 };
 411
 412 static int pcf2127_probe(struct device *dev, struct regmap *regmap,
 413                         const char *name, bool has_nvmem)
 414 {
 415         struct pcf2127 *pcf2127;
 416         int ret = 0;
 417
 418         dev_dbg(dev, "%s\n", __func__);
 419
 420         pcf2127 = devm_kzalloc(dev, sizeof(*pcf2127), GFP_KERNEL);
 421         if (!pcf2127)
 422                 return -ENOMEM;
 423
 424         pcf2127->regmap = regmap;
 425
 426         dev_set_drvdata(dev, pcf2127);
 427
 428         pcf2127->rtc = devm_rtc_allocate_device(dev);
 429         if (IS_ERR(pcf2127->rtc))
 430                 return PTR_ERR(pcf2127->rtc);
 431
 432         pcf2127->rtc->ops = &pcf2127_rtc_ops;
 433
 434         pcf2127->wdd.parent = dev;
 435         pcf2127->wdd.info = &pcf2127_wdt_info;
 436         pcf2127->wdd.ops = &pcf2127_watchdog_ops;
 437         pcf2127->wdd.min_timeout = PCF2127_WD_VAL_MIN;
 438         pcf2127->wdd.max_timeout = PCF2127_WD_VAL_MAX;
 439         pcf2127->wdd.timeout = PCF2127_WD_VAL_DEFAULT;
 440         pcf2127->wdd.min_hw_heartbeat_ms = 500;
 441
 442         watchdog_set_drvdata(&pcf2127->wdd, pcf2127);
 443
 444         if (has_nvmem) {
 445                 struct nvmem_config nvmem_cfg = {
 446                         .priv = pcf2127,
 447                         .reg_read = pcf2127_nvmem_read,
 448                         .reg_write = pcf2127_nvmem_write,
 449                         .size = 512,
 450                 };
 451
 452                 ret = rtc_nvmem_register(pcf2127->rtc, &nvmem_cfg);
 453         }
 454
 455         /*
 456          * Watchdog timer enabled and reset pin /RST activated when timed out.
 457          * Select 1Hz clock source for watchdog timer.
 458          * Timer is not started until WD_VAL is loaded with a valid value.
 459          * Note: Countdown timer disabled and not available.
 460          */
 461         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_WD_CTL,
 462                                  PCF2127_BIT_WD_CTL_CD1 |
 463                                  PCF2127_BIT_WD_CTL_CD0 |
 464                                  PCF2127_BIT_WD_CTL_TF1 |
 465                                  PCF2127_BIT_WD_CTL_TF0,
 466                                  PCF2127_BIT_WD_CTL_CD1 |
 467                                  PCF2127_BIT_WD_CTL_CD0 |
 468                                  PCF2127_BIT_WD_CTL_TF1);
 469         if (ret) {
 470                 dev_err(dev, "%s: watchdog config (wd_ctl) failed\n", __func__);
 471                 return ret;
 472         }
 473
 474 #ifdef CONFIG_WATCHDOG
 475         ret = devm_watchdog_register_device(dev, &pcf2127->wdd);
 476         if (ret)
 477                 return ret;
 478 #endif /* CONFIG_WATCHDOG */
 479
 480         /*
 481          * Disable battery low/switch-over timestamp and interrupts.
 482          * Clear battery interrupt flags which can block new trigger events.
 483          * Note: This is the default chip behaviour but added to ensure
 484          * correct tamper timestamp and interrupt function.
 485          */
 486         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL3,
 487                                  PCF2127_BIT_CTRL3_BTSE |
 488                                  PCF2127_BIT_CTRL3_BF |
 489                                  PCF2127_BIT_CTRL3_BIE |
 490                                  PCF2127_BIT_CTRL3_BLIE, 0);
 491         if (ret) {
 492                 dev_err(dev, "%s: interrupt config (ctrl3) failed\n",
 493                         __func__);
 494                 return ret;
 495         }
 496
 497         /*
 498          * Enable timestamp function and store timestamp of first trigger
 499          * event until TSF1 and TFS2 interrupt flags are cleared.
 500          */
 501         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_TS_CTRL,
 502                                  PCF2127_BIT_TS_CTRL_TSOFF |
 503                                  PCF2127_BIT_TS_CTRL_TSM,
 504                                  PCF2127_BIT_TS_CTRL_TSM);
 505         if (ret) {
 506                 dev_err(dev, "%s: tamper detection config (ts_ctrl) failed\n",
 507                         __func__);
 508                 return ret;
 509         }
 510
 511         /*
 512          * Enable interrupt generation when TSF1 or TSF2 timestamp flags
 513          * are set. Interrupt signal is an open-drain output and can be
 514          * left floating if unused.
 515          */
 516         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
 517                                  PCF2127_BIT_CTRL2_TSIE,
 518                                  PCF2127_BIT_CTRL2_TSIE);
 519         if (ret) {
 520                 dev_err(dev, "%s: tamper detection config (ctrl2) failed\n",
 521                         __func__);
 522                 return ret;
 523         }
 524
 525         ret = rtc_add_group(pcf2127->rtc, &pcf2127_attr_group);
 526         if (ret) {
 527                 dev_err(dev, "%s: tamper sysfs registering failed\n",
 528                         __func__);
 529                 return ret;
 530         }
 531
 532         return rtc_register_device(pcf2127->rtc);
 533 }
 534
 535 #ifdef CONFIG_OF
 536 static const struct of_device_id pcf2127_of_match[] = {
 537         { .compatible = "nxp,pcf2127" },
 538         { .compatible = "nxp,pcf2129" },
 539         {}
 540 };
 541 MODULE_DEVICE_TABLE(of, pcf2127_of_match);
 542 #endif
 543
 544 #if IS_ENABLED(CONFIG_I2C)
 545
 546 static int pcf2127_i2c_write(void *context, const void *data, size_t count)
 547 {
 548         struct device *dev = context;
 549         struct i2c_client *client = to_i2c_client(dev);
 550         int ret;
 551
 552         ret = i2c_master_send(client, data, count);
 553         if (ret != count)
 554                 return ret < 0 ? ret : -EIO;
 555
 556         return 0;
 557 }
 558
 559 static int pcf2127_i2c_gather_write(void *context,
 560                                 const void *reg, size_t reg_size,
 561                                 const void *val, size_t val_size)
 562 {
 563         struct device *dev = context;
 564         struct i2c_client *client = to_i2c_client(dev);
 565         int ret;
 566         void *buf;
 567
 568         if (WARN_ON(reg_size != 1))
 569                 return -EINVAL;
 570
 571         buf = kmalloc(val_size + 1, GFP_KERNEL);
 572         if (!buf)
 573                 return -ENOMEM;
 574
 575         memcpy(buf, reg, 1);
 576         memcpy(buf + 1, val, val_size);
 577
 578         ret = i2c_master_send(client, buf, val_size + 1);
 579
 580         kfree(buf);
 581
 582         if (ret != val_size + 1)
 583                 return ret < 0 ? ret : -EIO;
 584
 585         return 0;
 586 }
 587
 588 static int pcf2127_i2c_read(void *context, const void *reg, size_t reg_size,
 589                                 void *val, size_t val_size)
 590 {
 591         struct device *dev = context;
 592         struct i2c_client *client = to_i2c_client(dev);
 593         int ret;
 594
 595         if (WARN_ON(reg_size != 1))
 596                 return -EINVAL;
 597
 598         ret = i2c_master_send(client, reg, 1);
 599         if (ret != 1)
 600                 return ret < 0 ? ret : -EIO;
 601
 602         ret = i2c_master_recv(client, val, val_size);
 603         if (ret != val_size)
 604                 return ret < 0 ? ret : -EIO;
 605
 606         return 0;
 607 }
 608
 609 /*
 610  * The reason we need this custom regmap_bus instead of using regmap_init_i2c()
 611  * is that the STOP condition is required between set register address and
 612  * read register data when reading from registers.
 613  */
 614 static const struct regmap_bus pcf2127_i2c_regmap = {
 615         .write = pcf2127_i2c_write,
 616         .gather_write = pcf2127_i2c_gather_write,
 617         .read = pcf2127_i2c_read,
 618 };
 619
 620 static struct i2c_driver pcf2127_i2c_driver;
 621
 622 static int pcf2127_i2c_probe(struct i2c_client *client,
 623                                 const struct i2c_device_id *id)
 624 {
 625         struct regmap *regmap;
 626         static const struct regmap_config config = {
 627                 .reg_bits = 8,
 628                 .val_bits = 8,
 629         };
 630
 631         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 632                 return -ENODEV;
 633
 634         regmap = devm_regmap_init(&client->dev, &pcf2127_i2c_regmap,
 635                                         &client->dev, &config);
 636         if (IS_ERR(regmap)) {
 637                 dev_err(&client->dev, "%s: regmap allocation failed: %ld\n",
 638                         __func__, PTR_ERR(regmap));
 639                 return PTR_ERR(regmap);
 640         }
 641
 642         return pcf2127_probe(&client->dev, regmap,
 643                              pcf2127_i2c_driver.driver.name, id->driver_data);
 644 }
 645
 646 static const struct i2c_device_id pcf2127_i2c_id[] = {
 647         { "pcf2127", 1 },
 648         { "pcf2129", 0 },
 649         { }
 650 };
 651 MODULE_DEVICE_TABLE(i2c, pcf2127_i2c_id);
 652
 653 static struct i2c_driver pcf2127_i2c_driver = {
 654         .driver         = {
 655                 .name   = "rtc-pcf2127-i2c",
 656                 .of_match_table = of_match_ptr(pcf2127_of_match),
 657         },
 658         .probe          = pcf2127_i2c_probe,
 659         .id_table       = pcf2127_i2c_id,
 660 };
 661
 662 static int pcf2127_i2c_register_driver(void)
 663 {
 664         return i2c_add_driver(&pcf2127_i2c_driver);
 665 }
 666
 667 static void pcf2127_i2c_unregister_driver(void)
 668 {
 669         i2c_del_driver(&pcf2127_i2c_driver);
 670 }
 671
 672 #else
 673
 674 static int pcf2127_i2c_register_driver(void)
 675 {
 676         return 0;
 677 }
 678
 679 static void pcf2127_i2c_unregister_driver(void)
 680 {
 681 }
 682
 683 #endif
 684
 685 #if IS_ENABLED(CONFIG_SPI_MASTER)
 686
 687 static struct spi_driver pcf2127_spi_driver;
 688
 689 static int pcf2127_spi_probe(struct spi_device *spi)
 690 {
 691         static const struct regmap_config config = {
 692                 .reg_bits = 8,
 693                 .val_bits = 8,
 694                 .read_flag_mask = 0xa0,
 695                 .write_flag_mask = 0x20,
 696         };
 697         struct regmap *regmap;
 698
 699         regmap = devm_regmap_init_spi(spi, &config);
 700         if (IS_ERR(regmap)) {
 701                 dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
 702                         __func__, PTR_ERR(regmap));
 703                 return PTR_ERR(regmap);
 704         }
 705
 706         return pcf2127_probe(&spi->dev, regmap, pcf2127_spi_driver.driver.name,
 707                              spi_get_device_id(spi)->driver_data);
 708 }
 709
 710 static const struct spi_device_id pcf2127_spi_id[] = {
 711         { "pcf2127", 1 },
 712         { "pcf2129", 0 },
 713         { }
 714 };
 715 MODULE_DEVICE_TABLE(spi, pcf2127_spi_id);
 716
 717 static struct spi_driver pcf2127_spi_driver = {
 718         .driver         = {
 719                 .name   = "rtc-pcf2127-spi",
 720                 .of_match_table = of_match_ptr(pcf2127_of_match),
 721         },
 722         .probe          = pcf2127_spi_probe,
 723         .id_table       = pcf2127_spi_id,
 724 };
 725
 726 static int pcf2127_spi_register_driver(void)
 727 {
 728         return spi_register_driver(&pcf2127_spi_driver);
 729 }
 730
 731 static void pcf2127_spi_unregister_driver(void)
 732 {
 733         spi_unregister_driver(&pcf2127_spi_driver);
 734 }
 735
 736 #else
 737
 738 static int pcf2127_spi_register_driver(void)
 739 {
 740         return 0;
 741 }
 742
 743 static void pcf2127_spi_unregister_driver(void)
 744 {
 745 }
 746
 747 #endif
 748
 749 static int __init pcf2127_init(void)
 750 {
 751         int ret;
 752
 753         ret = pcf2127_i2c_register_driver();
 754         if (ret) {
 755                 pr_err("Failed to register pcf2127 i2c driver: %d\n", ret);
 756                 return ret;
 757         }
 758
 759         ret = pcf2127_spi_register_driver();
 760         if (ret) {
 761                 pr_err("Failed to register pcf2127 spi driver: %d\n", ret);
 762                 pcf2127_i2c_unregister_driver();
 763         }
 764
 765         return ret;
 766 }
 767 module_init(pcf2127_init)
 768
 769 static void __exit pcf2127_exit(void)
 770 {
 771         pcf2127_spi_unregister_driver();
 772         pcf2127_i2c_unregister_driver();
 773 }
 774 module_exit(pcf2127_exit)
 775
 776 MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
 777 MODULE_DESCRIPTION("NXP PCF2127/29 RTC driver");
 778 MODULE_LICENSE("GPL v2");