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 <[email protected]>
   7  *
   8  * Watchdog and tamper functions
   9  * Author: Bruno Thomsen <[email protected]>
  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         ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_RAM_RD_CMD,
 234                                val, bytes);
 235
 236         return ret ?: bytes;
 237 }
 238
 239 static int pcf2127_nvmem_write(void *priv, unsigned int offset,
 240                                void *val, size_t bytes)
 241 {
 242         struct pcf2127 *pcf2127 = priv;
 243         int ret;
 244         unsigned char offsetbuf[] = { offset >> 8, offset };
 245
 246         ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_ADDR_MSB,
 247                                 offsetbuf, 2);
 248         if (ret)
 249                 return ret;
 250
 251         ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_WRT_CMD,
 252                                 val, bytes);
 253
 254         return ret ?: bytes;
 255 }
 256
 257 /* watchdog driver */
 258
 259 static int pcf2127_wdt_ping(struct watchdog_device *wdd)
 260 {
 261         struct pcf2127 *pcf2127 = watchdog_get_drvdata(wdd);
 262
 263         return regmap_write(pcf2127->regmap, PCF2127_REG_WD_VAL, wdd->timeout);
 264 }
 265
 266 /*
 267  * Restart watchdog timer if feature is active.
 268  *
 269  * Note: Reading CTRL2 register causes watchdog to stop which is unfortunate,
 270  * since register also contain control/status flags for other features.
 271  * Always call this function after reading CTRL2 register.
 272  */
 273 static int pcf2127_wdt_active_ping(struct watchdog_device *wdd)
 274 {
 275         int ret = 0;
 276
 277         if (watchdog_active(wdd)) {
 278                 ret = pcf2127_wdt_ping(wdd);
 279                 if (ret)
 280                         dev_err(wdd->parent,
 281                                 "%s: watchdog restart failed, ret=%d\n",
 282                                 __func__, ret);
 283         }
 284
 285         return ret;
 286 }
 287
 288 static int pcf2127_wdt_start(struct watchdog_device *wdd)
 289 {
 290         return pcf2127_wdt_ping(wdd);
 291 }
 292
 293 static int pcf2127_wdt_stop(struct watchdog_device *wdd)
 294 {
 295         struct pcf2127 *pcf2127 = watchdog_get_drvdata(wdd);
 296
 297         return regmap_write(pcf2127->regmap, PCF2127_REG_WD_VAL,
 298                             PCF2127_WD_VAL_STOP);
 299 }
 300
 301 static int pcf2127_wdt_set_timeout(struct watchdog_device *wdd,
 302                                    unsigned int new_timeout)
 303 {
 304         dev_dbg(wdd->parent, "new watchdog timeout: %is (old: %is)\n",
 305                 new_timeout, wdd->timeout);
 306
 307         wdd->timeout = new_timeout;
 308
 309         return pcf2127_wdt_active_ping(wdd);
 310 }
 311
 312 static const struct watchdog_info pcf2127_wdt_info = {
 313         .identity = "NXP PCF2127/PCF2129 Watchdog",
 314         .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
 315 };
 316
 317 static const struct watchdog_ops pcf2127_watchdog_ops = {
 318         .owner = THIS_MODULE,
 319         .start = pcf2127_wdt_start,
 320         .stop = pcf2127_wdt_stop,
 321         .ping = pcf2127_wdt_ping,
 322         .set_timeout = pcf2127_wdt_set_timeout,
 323 };
 324
 325 /* sysfs interface */
 326
 327 static ssize_t timestamp0_store(struct device *dev,
 328                                 struct device_attribute *attr,
 329                                 const char *buf, size_t count)
 330 {
 331         struct pcf2127 *pcf2127 = dev_get_drvdata(dev->parent);
 332         int ret;
 333
 334         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL1,
 335                                  PCF2127_BIT_CTRL1_TSF1, 0);
 336         if (ret) {
 337                 dev_err(dev, "%s: update ctrl1 ret=%d\n", __func__, ret);
 338                 return ret;
 339         }
 340
 341         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
 342                                  PCF2127_BIT_CTRL2_TSF2, 0);
 343         if (ret) {
 344                 dev_err(dev, "%s: update ctrl2 ret=%d\n", __func__, ret);
 345                 return ret;
 346         }
 347
 348         ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
 349         if (ret)
 350                 return ret;
 351
 352         return count;
 353 };
 354
 355 static ssize_t timestamp0_show(struct device *dev,
 356                                struct device_attribute *attr, char *buf)
 357 {
 358         struct pcf2127 *pcf2127 = dev_get_drvdata(dev->parent);
 359         struct rtc_time tm;
 360         int ret;
 361         unsigned char data[25];
 362
 363         ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_CTRL1, data,
 364                                sizeof(data));
 365         if (ret) {
 366                 dev_err(dev, "%s: read error ret=%d\n", __func__, ret);
 367                 return ret;
 368         }
 369
 370         dev_dbg(dev,
 371                 "%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, ts_sc=%02x, "
 372                 "ts_mn=%02x, ts_hr=%02x, ts_dm=%02x, ts_mo=%02x, ts_yr=%02x\n",
 373                 __func__, data[PCF2127_REG_CTRL1], data[PCF2127_REG_CTRL2],
 374                 data[PCF2127_REG_CTRL3], data[PCF2127_REG_TS_SC],
 375                 data[PCF2127_REG_TS_MN], data[PCF2127_REG_TS_HR],
 376                 data[PCF2127_REG_TS_DM], data[PCF2127_REG_TS_MO],
 377                 data[PCF2127_REG_TS_YR]);
 378
 379         ret = pcf2127_wdt_active_ping(&pcf2127->wdd);
 380         if (ret)
 381                 return ret;
 382
 383         if (!(data[PCF2127_REG_CTRL1] & PCF2127_BIT_CTRL1_TSF1) &&
 384             !(data[PCF2127_REG_CTRL2] & PCF2127_BIT_CTRL2_TSF2))
 385                 return 0;
 386
 387         tm.tm_sec = bcd2bin(data[PCF2127_REG_TS_SC] & 0x7F);
 388         tm.tm_min = bcd2bin(data[PCF2127_REG_TS_MN] & 0x7F);
 389         tm.tm_hour = bcd2bin(data[PCF2127_REG_TS_HR] & 0x3F);
 390         tm.tm_mday = bcd2bin(data[PCF2127_REG_TS_DM] & 0x3F);
 391         /* TS_MO register (month) value range: 1-12 */
 392         tm.tm_mon = bcd2bin(data[PCF2127_REG_TS_MO] & 0x1F) - 1;
 393         tm.tm_year = bcd2bin(data[PCF2127_REG_TS_YR]);
 394         if (tm.tm_year < 70)
 395                 tm.tm_year += 100; /* assume we are in 1970...2069 */
 396
 397         ret = rtc_valid_tm(&tm);
 398         if (ret)
 399                 return ret;
 400
 401         return sprintf(buf, "%llu\n",
 402                        (unsigned long long)rtc_tm_to_time64(&tm));
 403 };
 404
 405 static DEVICE_ATTR_RW(timestamp0);
 406
 407 static struct attribute *pcf2127_attrs[] = {
 408         &dev_attr_timestamp0.attr,
 409         NULL
 410 };
 411
 412 static const struct attribute_group pcf2127_attr_group = {
 413         .attrs  = pcf2127_attrs,
 414 };
 415
 416 static int pcf2127_probe(struct device *dev, struct regmap *regmap,
 417                         const char *name, bool has_nvmem)
 418 {
 419         struct pcf2127 *pcf2127;
 420         int ret = 0;
 421
 422         dev_dbg(dev, "%s\n", __func__);
 423
 424         pcf2127 = devm_kzalloc(dev, sizeof(*pcf2127), GFP_KERNEL);
 425         if (!pcf2127)
 426                 return -ENOMEM;
 427
 428         pcf2127->regmap = regmap;
 429
 430         dev_set_drvdata(dev, pcf2127);
 431
 432         pcf2127->rtc = devm_rtc_allocate_device(dev);
 433         if (IS_ERR(pcf2127->rtc))
 434                 return PTR_ERR(pcf2127->rtc);
 435
 436         pcf2127->rtc->ops = &pcf2127_rtc_ops;
 437
 438         pcf2127->wdd.parent = dev;
 439         pcf2127->wdd.info = &pcf2127_wdt_info;
 440         pcf2127->wdd.ops = &pcf2127_watchdog_ops;
 441         pcf2127->wdd.min_timeout = PCF2127_WD_VAL_MIN;
 442         pcf2127->wdd.max_timeout = PCF2127_WD_VAL_MAX;
 443         pcf2127->wdd.timeout = PCF2127_WD_VAL_DEFAULT;
 444         pcf2127->wdd.min_hw_heartbeat_ms = 500;
 445
 446         watchdog_set_drvdata(&pcf2127->wdd, pcf2127);
 447
 448         if (has_nvmem) {
 449                 struct nvmem_config nvmem_cfg = {
 450                         .priv = pcf2127,
 451                         .reg_read = pcf2127_nvmem_read,
 452                         .reg_write = pcf2127_nvmem_write,
 453                         .size = 512,
 454                 };
 455
 456                 ret = rtc_nvmem_register(pcf2127->rtc, &nvmem_cfg);
 457         }
 458
 459         /*
 460          * Watchdog timer enabled and reset pin /RST activated when timed out.
 461          * Select 1Hz clock source for watchdog timer.
 462          * Timer is not started until WD_VAL is loaded with a valid value.
 463          * Note: Countdown timer disabled and not available.
 464          */
 465         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_WD_CTL,
 466                                  PCF2127_BIT_WD_CTL_CD1 |
 467                                  PCF2127_BIT_WD_CTL_CD0 |
 468                                  PCF2127_BIT_WD_CTL_TF1 |
 469                                  PCF2127_BIT_WD_CTL_TF0,
 470                                  PCF2127_BIT_WD_CTL_CD1 |
 471                                  PCF2127_BIT_WD_CTL_CD0 |
 472                                  PCF2127_BIT_WD_CTL_TF1);
 473         if (ret) {
 474                 dev_err(dev, "%s: watchdog config (wd_ctl) failed\n", __func__);
 475                 return ret;
 476         }
 477
 478 #ifdef CONFIG_WATCHDOG
 479         ret = devm_watchdog_register_device(dev, &pcf2127->wdd);
 480         if (ret)
 481                 return ret;
 482 #endif /* CONFIG_WATCHDOG */
 483
 484         /*
 485          * Disable battery low/switch-over timestamp and interrupts.
 486          * Clear battery interrupt flags which can block new trigger events.
 487          * Note: This is the default chip behaviour but added to ensure
 488          * correct tamper timestamp and interrupt function.
 489          */
 490         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL3,
 491                                  PCF2127_BIT_CTRL3_BTSE |
 492                                  PCF2127_BIT_CTRL3_BF |
 493                                  PCF2127_BIT_CTRL3_BIE |
 494                                  PCF2127_BIT_CTRL3_BLIE, 0);
 495         if (ret) {
 496                 dev_err(dev, "%s: interrupt config (ctrl3) failed\n",
 497                         __func__);
 498                 return ret;
 499         }
 500
 501         /*
 502          * Enable timestamp function and store timestamp of first trigger
 503          * event until TSF1 and TFS2 interrupt flags are cleared.
 504          */
 505         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_TS_CTRL,
 506                                  PCF2127_BIT_TS_CTRL_TSOFF |
 507                                  PCF2127_BIT_TS_CTRL_TSM,
 508                                  PCF2127_BIT_TS_CTRL_TSM);
 509         if (ret) {
 510                 dev_err(dev, "%s: tamper detection config (ts_ctrl) failed\n",
 511                         __func__);
 512                 return ret;
 513         }
 514
 515         /*
 516          * Enable interrupt generation when TSF1 or TSF2 timestamp flags
 517          * are set. Interrupt signal is an open-drain output and can be
 518          * left floating if unused.
 519          */
 520         ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL2,
 521                                  PCF2127_BIT_CTRL2_TSIE,
 522                                  PCF2127_BIT_CTRL2_TSIE);
 523         if (ret) {
 524                 dev_err(dev, "%s: tamper detection config (ctrl2) failed\n",
 525                         __func__);
 526                 return ret;
 527         }
 528
 529         ret = rtc_add_group(pcf2127->rtc, &pcf2127_attr_group);
 530         if (ret) {
 531                 dev_err(dev, "%s: tamper sysfs registering failed\n",
 532                         __func__);
 533                 return ret;
 534         }
 535
 536         return rtc_register_device(pcf2127->rtc);
 537 }
 538
 539 #ifdef CONFIG_OF
 540 static const struct of_device_id pcf2127_of_match[] = {
 541         { .compatible = "nxp,pcf2127" },
 542         { .compatible = "nxp,pcf2129" },
 543         {}
 544 };
 545 MODULE_DEVICE_TABLE(of, pcf2127_of_match);
 546 #endif
 547
 548 #if IS_ENABLED(CONFIG_I2C)
 549
 550 static int pcf2127_i2c_write(void *context, const void *data, size_t count)
 551 {
 552         struct device *dev = context;
 553         struct i2c_client *client = to_i2c_client(dev);
 554         int ret;
 555
 556         ret = i2c_master_send(client, data, count);
 557         if (ret != count)
 558                 return ret < 0 ? ret : -EIO;
 559
 560         return 0;
 561 }
 562
 563 static int pcf2127_i2c_gather_write(void *context,
 564                                 const void *reg, size_t reg_size,
 565                                 const void *val, size_t val_size)
 566 {
 567         struct device *dev = context;
 568         struct i2c_client *client = to_i2c_client(dev);
 569         int ret;
 570         void *buf;
 571
 572         if (WARN_ON(reg_size != 1))
 573                 return -EINVAL;
 574
 575         buf = kmalloc(val_size + 1, GFP_KERNEL);
 576         if (!buf)
 577                 return -ENOMEM;
 578
 579         memcpy(buf, reg, 1);
 580         memcpy(buf + 1, val, val_size);
 581
 582         ret = i2c_master_send(client, buf, val_size + 1);
 583
 584         kfree(buf);
 585
 586         if (ret != val_size + 1)
 587                 return ret < 0 ? ret : -EIO;
 588
 589         return 0;
 590 }
 591
 592 static int pcf2127_i2c_read(void *context, const void *reg, size_t reg_size,
 593                                 void *val, size_t val_size)
 594 {
 595         struct device *dev = context;
 596         struct i2c_client *client = to_i2c_client(dev);
 597         int ret;
 598
 599         if (WARN_ON(reg_size != 1))
 600                 return -EINVAL;
 601
 602         ret = i2c_master_send(client, reg, 1);
 603         if (ret != 1)
 604                 return ret < 0 ? ret : -EIO;
 605
 606         ret = i2c_master_recv(client, val, val_size);
 607         if (ret != val_size)
 608                 return ret < 0 ? ret : -EIO;
 609
 610         return 0;
 611 }
 612
 613 /*
 614  * The reason we need this custom regmap_bus instead of using regmap_init_i2c()
 615  * is that the STOP condition is required between set register address and
 616  * read register data when reading from registers.
 617  */
 618 static const struct regmap_bus pcf2127_i2c_regmap = {
 619         .write = pcf2127_i2c_write,
 620         .gather_write = pcf2127_i2c_gather_write,
 621         .read = pcf2127_i2c_read,
 622 };
 623
 624 static struct i2c_driver pcf2127_i2c_driver;
 625
 626 static int pcf2127_i2c_probe(struct i2c_client *client,
 627                                 const struct i2c_device_id *id)
 628 {
 629         struct regmap *regmap;
 630         static const struct regmap_config config = {
 631                 .reg_bits = 8,
 632                 .val_bits = 8,
 633         };
 634
 635         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 636                 return -ENODEV;
 637
 638         regmap = devm_regmap_init(&client->dev, &pcf2127_i2c_regmap,
 639                                         &client->dev, &config);
 640         if (IS_ERR(regmap)) {
 641                 dev_err(&client->dev, "%s: regmap allocation failed: %ld\n",
 642                         __func__, PTR_ERR(regmap));
 643                 return PTR_ERR(regmap);
 644         }
 645
 646         return pcf2127_probe(&client->dev, regmap,
 647                              pcf2127_i2c_driver.driver.name, id->driver_data);
 648 }
 649
 650 static const struct i2c_device_id pcf2127_i2c_id[] = {
 651         { "pcf2127", 1 },
 652         { "pcf2129", 0 },
 653         { }
 654 };
 655 MODULE_DEVICE_TABLE(i2c, pcf2127_i2c_id);
 656
 657 static struct i2c_driver pcf2127_i2c_driver = {
 658         .driver         = {
 659                 .name   = "rtc-pcf2127-i2c",
 660                 .of_match_table = of_match_ptr(pcf2127_of_match),
 661         },
 662         .probe          = pcf2127_i2c_probe,
 663         .id_table       = pcf2127_i2c_id,
 664 };
 665
 666 static int pcf2127_i2c_register_driver(void)
 667 {
 668         return i2c_add_driver(&pcf2127_i2c_driver);
 669 }
 670
 671 static void pcf2127_i2c_unregister_driver(void)
 672 {
 673         i2c_del_driver(&pcf2127_i2c_driver);
 674 }
 675
 676 #else
 677
 678 static int pcf2127_i2c_register_driver(void)
 679 {
 680         return 0;
 681 }
 682
 683 static void pcf2127_i2c_unregister_driver(void)
 684 {
 685 }
 686
 687 #endif
 688
 689 #if IS_ENABLED(CONFIG_SPI_MASTER)
 690
 691 static struct spi_driver pcf2127_spi_driver;
 692
 693 static int pcf2127_spi_probe(struct spi_device *spi)
 694 {
 695         static const struct regmap_config config = {
 696                 .reg_bits = 8,
 697                 .val_bits = 8,
 698                 .read_flag_mask = 0xa0,
 699                 .write_flag_mask = 0x20,
 700         };
 701         struct regmap *regmap;
 702
 703         regmap = devm_regmap_init_spi(spi, &config);
 704         if (IS_ERR(regmap)) {
 705                 dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
 706                         __func__, PTR_ERR(regmap));
 707                 return PTR_ERR(regmap);
 708         }
 709
 710         return pcf2127_probe(&spi->dev, regmap, pcf2127_spi_driver.driver.name,
 711                              spi_get_device_id(spi)->driver_data);
 712 }
 713
 714 static const struct spi_device_id pcf2127_spi_id[] = {
 715         { "pcf2127", 1 },
 716         { "pcf2129", 0 },
 717         { }
 718 };
 719 MODULE_DEVICE_TABLE(spi, pcf2127_spi_id);
 720
 721 static struct spi_driver pcf2127_spi_driver = {
 722         .driver         = {
 723                 .name   = "rtc-pcf2127-spi",
 724                 .of_match_table = of_match_ptr(pcf2127_of_match),
 725         },
 726         .probe          = pcf2127_spi_probe,
 727         .id_table       = pcf2127_spi_id,
 728 };
 729
 730 static int pcf2127_spi_register_driver(void)
 731 {
 732         return spi_register_driver(&pcf2127_spi_driver);
 733 }
 734
 735 static void pcf2127_spi_unregister_driver(void)
 736 {
 737         spi_unregister_driver(&pcf2127_spi_driver);
 738 }
 739
 740 #else
 741
 742 static int pcf2127_spi_register_driver(void)
 743 {
 744         return 0;
 745 }
 746
 747 static void pcf2127_spi_unregister_driver(void)
 748 {
 749 }
 750
 751 #endif
 752
 753 static int __init pcf2127_init(void)
 754 {
 755         int ret;
 756
 757         ret = pcf2127_i2c_register_driver();
 758         if (ret) {
 759                 pr_err("Failed to register pcf2127 i2c driver: %d\n", ret);
 760                 return ret;
 761         }
 762
 763         ret = pcf2127_spi_register_driver();
 764         if (ret) {
 765                 pr_err("Failed to register pcf2127 spi driver: %d\n", ret);
 766                 pcf2127_i2c_unregister_driver();
 767         }
 768
 769         return ret;
 770 }
 771 module_init(pcf2127_init)
 772
 773 static void __exit pcf2127_exit(void)
 774 {
 775         pcf2127_spi_unregister_driver();
 776         pcf2127_i2c_unregister_driver();
 777 }
 778 module_exit(pcf2127_exit)
 779
 780 MODULE_AUTHOR("Renaud Cerrato <[email protected]>");
 781 MODULE_DESCRIPTION("NXP PCF2127/29 RTC driver");
 782 MODULE_LICENSE("GPL v2");