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  * based on the other drivers in this same directory.
   9  *
  10  * Datasheet: http://cache.nxp.com/documents/data_sheet/PCF2127.pdf
  11  */
  12
  13 #include <linux/i2c.h>
  14 #include <linux/spi/spi.h>
  15 #include <linux/bcd.h>
  16 #include <linux/rtc.h>
  17 #include <linux/slab.h>
  18 #include <linux/module.h>
  19 #include <linux/of.h>
  20 #include <linux/regmap.h>
  21
  22 /* Control register 1 */
  23 #define PCF2127_REG_CTRL1               0x00
  24 /* Control register 2 */
  25 #define PCF2127_REG_CTRL2               0x01
  26 /* Control register 3 */
  27 #define PCF2127_REG_CTRL3               0x02
  28 #define PCF2127_BIT_CTRL3_BLF                   BIT(2)
  29 /* Time and date registers */
  30 #define PCF2127_REG_SC                  0x03
  31 #define PCF2127_BIT_SC_OSF                      BIT(7)
  32 #define PCF2127_REG_MN                  0x04
  33 #define PCF2127_REG_HR                  0x05
  34 #define PCF2127_REG_DM                  0x06
  35 #define PCF2127_REG_DW                  0x07
  36 #define PCF2127_REG_MO                  0x08
  37 #define PCF2127_REG_YR                  0x09
  38 /*
  39  * RAM registers
  40  * PCF2127 has 512 bytes general-purpose static RAM (SRAM) that is
  41  * battery backed and can survive a power outage.
  42  * PCF2129 doesn't have this feature.
  43  */
  44 #define PCF2127_REG_RAM_ADDR_MSB        0x1A
  45 #define PCF2127_REG_RAM_WRT_CMD         0x1C
  46 #define PCF2127_REG_RAM_RD_CMD          0x1D
  47
  48
  49 struct pcf2127 {
  50         struct rtc_device *rtc;
  51         struct regmap *regmap;
  52 };
  53
  54 /*
  55  * In the routines that deal directly with the pcf2127 hardware, we use
  56  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
  57  */
  58 static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm)
  59 {
  60         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
  61         unsigned char buf[10];
  62         int ret;
  63
  64         /*
  65          * Avoid reading CTRL2 register as it causes WD_VAL register
  66          * value to reset to 0 which means watchdog is stopped.
  67          */
  68         ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_CTRL3,
  69                                (buf + PCF2127_REG_CTRL3),
  70                                ARRAY_SIZE(buf) - PCF2127_REG_CTRL3);
  71         if (ret) {
  72                 dev_err(dev, "%s: read error\n", __func__);
  73                 return ret;
  74         }
  75
  76         if (buf[PCF2127_REG_CTRL3] & PCF2127_BIT_CTRL3_BLF)
  77                 dev_info(dev,
  78                         "low voltage detected, check/replace RTC battery.\n");
  79
  80         /* Clock integrity is not guaranteed when OSF flag is set. */
  81         if (buf[PCF2127_REG_SC] & PCF2127_BIT_SC_OSF) {
  82                 /*
  83                  * no need clear the flag here,
  84                  * it will be cleared once the new date is saved
  85                  */
  86                 dev_warn(dev,
  87                          "oscillator stop detected, date/time is not reliable\n");
  88                 return -EINVAL;
  89         }
  90
  91         dev_dbg(dev,
  92                 "%s: raw data is cr3=%02x, sec=%02x, min=%02x, hr=%02x, "
  93                 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
  94                 __func__, buf[PCF2127_REG_CTRL3], buf[PCF2127_REG_SC],
  95                 buf[PCF2127_REG_MN], buf[PCF2127_REG_HR],
  96                 buf[PCF2127_REG_DM], buf[PCF2127_REG_DW],
  97                 buf[PCF2127_REG_MO], buf[PCF2127_REG_YR]);
  98
  99         tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F);
 100         tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F);
 101         tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */
 102         tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F);
 103         tm->tm_wday = buf[PCF2127_REG_DW] & 0x07;
 104         tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
 105         tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]);
 106         if (tm->tm_year < 70)
 107                 tm->tm_year += 100;     /* assume we are in 1970...2069 */
 108
 109         dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 110                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 111                 __func__,
 112                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 113                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 114
 115         return 0;
 116 }
 117
 118 static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
 119 {
 120         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
 121         unsigned char buf[7];
 122         int i = 0, err;
 123
 124         dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "
 125                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 126                 __func__,
 127                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 128                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 129
 130         /* hours, minutes and seconds */
 131         buf[i++] = bin2bcd(tm->tm_sec); /* this will also clear OSF flag */
 132         buf[i++] = bin2bcd(tm->tm_min);
 133         buf[i++] = bin2bcd(tm->tm_hour);
 134         buf[i++] = bin2bcd(tm->tm_mday);
 135         buf[i++] = tm->tm_wday & 0x07;
 136
 137         /* month, 1 - 12 */
 138         buf[i++] = bin2bcd(tm->tm_mon + 1);
 139
 140         /* year */
 141         buf[i++] = bin2bcd(tm->tm_year % 100);
 142
 143         /* write register's data */
 144         err = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_SC, buf, i);
 145         if (err) {
 146                 dev_err(dev,
 147                         "%s: err=%d", __func__, err);
 148                 return err;
 149         }
 150
 151         return 0;
 152 }
 153
 154 #ifdef CONFIG_RTC_INTF_DEV
 155 static int pcf2127_rtc_ioctl(struct device *dev,
 156                                 unsigned int cmd, unsigned long arg)
 157 {
 158         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
 159         int touser;
 160         int ret;
 161
 162         switch (cmd) {
 163         case RTC_VL_READ:
 164                 ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &touser);
 165                 if (ret)
 166                         return ret;
 167
 168                 touser = touser & PCF2127_BIT_CTRL3_BLF ? 1 : 0;
 169
 170                 if (copy_to_user((void __user *)arg, &touser, sizeof(int)))
 171                         return -EFAULT;
 172                 return 0;
 173         default:
 174                 return -ENOIOCTLCMD;
 175         }
 176 }
 177 #else
 178 #define pcf2127_rtc_ioctl NULL
 179 #endif
 180
 181 static const struct rtc_class_ops pcf2127_rtc_ops = {
 182         .ioctl          = pcf2127_rtc_ioctl,
 183         .read_time      = pcf2127_rtc_read_time,
 184         .set_time       = pcf2127_rtc_set_time,
 185 };
 186
 187 static int pcf2127_nvmem_read(void *priv, unsigned int offset,
 188                               void *val, size_t bytes)
 189 {
 190         struct pcf2127 *pcf2127 = priv;
 191         int ret;
 192         unsigned char offsetbuf[] = { offset >> 8, offset };
 193
 194         ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_ADDR_MSB,
 195                                 offsetbuf, 2);
 196         if (ret)
 197                 return ret;
 198
 199         ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_RAM_RD_CMD,
 200                                val, bytes);
 201
 202         return ret ?: bytes;
 203 }
 204
 205 static int pcf2127_nvmem_write(void *priv, unsigned int offset,
 206                                void *val, size_t bytes)
 207 {
 208         struct pcf2127 *pcf2127 = priv;
 209         int ret;
 210         unsigned char offsetbuf[] = { offset >> 8, offset };
 211
 212         ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_ADDR_MSB,
 213                                 offsetbuf, 2);
 214         if (ret)
 215                 return ret;
 216
 217         ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_WRT_CMD,
 218                                 val, bytes);
 219
 220         return ret ?: bytes;
 221 }
 222
 223 static int pcf2127_probe(struct device *dev, struct regmap *regmap,
 224                         const char *name, bool has_nvmem)
 225 {
 226         struct pcf2127 *pcf2127;
 227         int ret = 0;
 228
 229         dev_dbg(dev, "%s\n", __func__);
 230
 231         pcf2127 = devm_kzalloc(dev, sizeof(*pcf2127), GFP_KERNEL);
 232         if (!pcf2127)
 233                 return -ENOMEM;
 234
 235         pcf2127->regmap = regmap;
 236
 237         dev_set_drvdata(dev, pcf2127);
 238
 239         pcf2127->rtc = devm_rtc_allocate_device(dev);
 240         if (IS_ERR(pcf2127->rtc))
 241                 return PTR_ERR(pcf2127->rtc);
 242
 243         pcf2127->rtc->ops = &pcf2127_rtc_ops;
 244
 245         if (has_nvmem) {
 246                 struct nvmem_config nvmem_cfg = {
 247                         .priv = pcf2127,
 248                         .reg_read = pcf2127_nvmem_read,
 249                         .reg_write = pcf2127_nvmem_write,
 250                         .size = 512,
 251                 };
 252
 253                 ret = rtc_nvmem_register(pcf2127->rtc, &nvmem_cfg);
 254         }
 255
 256         return rtc_register_device(pcf2127->rtc);
 257 }
 258
 259 #ifdef CONFIG_OF
 260 static const struct of_device_id pcf2127_of_match[] = {
 261         { .compatible = "nxp,pcf2127" },
 262         { .compatible = "nxp,pcf2129" },
 263         {}
 264 };
 265 MODULE_DEVICE_TABLE(of, pcf2127_of_match);
 266 #endif
 267
 268 #if IS_ENABLED(CONFIG_I2C)
 269
 270 static int pcf2127_i2c_write(void *context, const void *data, size_t count)
 271 {
 272         struct device *dev = context;
 273         struct i2c_client *client = to_i2c_client(dev);
 274         int ret;
 275
 276         ret = i2c_master_send(client, data, count);
 277         if (ret != count)
 278                 return ret < 0 ? ret : -EIO;
 279
 280         return 0;
 281 }
 282
 283 static int pcf2127_i2c_gather_write(void *context,
 284                                 const void *reg, size_t reg_size,
 285                                 const void *val, size_t val_size)
 286 {
 287         struct device *dev = context;
 288         struct i2c_client *client = to_i2c_client(dev);
 289         int ret;
 290         void *buf;
 291
 292         if (WARN_ON(reg_size != 1))
 293                 return -EINVAL;
 294
 295         buf = kmalloc(val_size + 1, GFP_KERNEL);
 296         if (!buf)
 297                 return -ENOMEM;
 298
 299         memcpy(buf, reg, 1);
 300         memcpy(buf + 1, val, val_size);
 301
 302         ret = i2c_master_send(client, buf, val_size + 1);
 303
 304         kfree(buf);
 305
 306         if (ret != val_size + 1)
 307                 return ret < 0 ? ret : -EIO;
 308
 309         return 0;
 310 }
 311
 312 static int pcf2127_i2c_read(void *context, const void *reg, size_t reg_size,
 313                                 void *val, size_t val_size)
 314 {
 315         struct device *dev = context;
 316         struct i2c_client *client = to_i2c_client(dev);
 317         int ret;
 318
 319         if (WARN_ON(reg_size != 1))
 320                 return -EINVAL;
 321
 322         ret = i2c_master_send(client, reg, 1);
 323         if (ret != 1)
 324                 return ret < 0 ? ret : -EIO;
 325
 326         ret = i2c_master_recv(client, val, val_size);
 327         if (ret != val_size)
 328                 return ret < 0 ? ret : -EIO;
 329
 330         return 0;
 331 }
 332
 333 /*
 334  * The reason we need this custom regmap_bus instead of using regmap_init_i2c()
 335  * is that the STOP condition is required between set register address and
 336  * read register data when reading from registers.
 337  */
 338 static const struct regmap_bus pcf2127_i2c_regmap = {
 339         .write = pcf2127_i2c_write,
 340         .gather_write = pcf2127_i2c_gather_write,
 341         .read = pcf2127_i2c_read,
 342 };
 343
 344 static struct i2c_driver pcf2127_i2c_driver;
 345
 346 static int pcf2127_i2c_probe(struct i2c_client *client,
 347                                 const struct i2c_device_id *id)
 348 {
 349         struct regmap *regmap;
 350         static const struct regmap_config config = {
 351                 .reg_bits = 8,
 352                 .val_bits = 8,
 353         };
 354
 355         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 356                 return -ENODEV;
 357
 358         regmap = devm_regmap_init(&client->dev, &pcf2127_i2c_regmap,
 359                                         &client->dev, &config);
 360         if (IS_ERR(regmap)) {
 361                 dev_err(&client->dev, "%s: regmap allocation failed: %ld\n",
 362                         __func__, PTR_ERR(regmap));
 363                 return PTR_ERR(regmap);
 364         }
 365
 366         return pcf2127_probe(&client->dev, regmap,
 367                              pcf2127_i2c_driver.driver.name, id->driver_data);
 368 }
 369
 370 static const struct i2c_device_id pcf2127_i2c_id[] = {
 371         { "pcf2127", 1 },
 372         { "pcf2129", 0 },
 373         { }
 374 };
 375 MODULE_DEVICE_TABLE(i2c, pcf2127_i2c_id);
 376
 377 static struct i2c_driver pcf2127_i2c_driver = {
 378         .driver         = {
 379                 .name   = "rtc-pcf2127-i2c",
 380                 .of_match_table = of_match_ptr(pcf2127_of_match),
 381         },
 382         .probe          = pcf2127_i2c_probe,
 383         .id_table       = pcf2127_i2c_id,
 384 };
 385
 386 static int pcf2127_i2c_register_driver(void)
 387 {
 388         return i2c_add_driver(&pcf2127_i2c_driver);
 389 }
 390
 391 static void pcf2127_i2c_unregister_driver(void)
 392 {
 393         i2c_del_driver(&pcf2127_i2c_driver);
 394 }
 395
 396 #else
 397
 398 static int pcf2127_i2c_register_driver(void)
 399 {
 400         return 0;
 401 }
 402
 403 static void pcf2127_i2c_unregister_driver(void)
 404 {
 405 }
 406
 407 #endif
 408
 409 #if IS_ENABLED(CONFIG_SPI_MASTER)
 410
 411 static struct spi_driver pcf2127_spi_driver;
 412
 413 static int pcf2127_spi_probe(struct spi_device *spi)
 414 {
 415         static const struct regmap_config config = {
 416                 .reg_bits = 8,
 417                 .val_bits = 8,
 418                 .read_flag_mask = 0xa0,
 419                 .write_flag_mask = 0x20,
 420         };
 421         struct regmap *regmap;
 422
 423         regmap = devm_regmap_init_spi(spi, &config);
 424         if (IS_ERR(regmap)) {
 425                 dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
 426                         __func__, PTR_ERR(regmap));
 427                 return PTR_ERR(regmap);
 428         }
 429
 430         return pcf2127_probe(&spi->dev, regmap, pcf2127_spi_driver.driver.name,
 431                              spi_get_device_id(spi)->driver_data);
 432 }
 433
 434 static const struct spi_device_id pcf2127_spi_id[] = {
 435         { "pcf2127", 1 },
 436         { "pcf2129", 0 },
 437         { }
 438 };
 439 MODULE_DEVICE_TABLE(spi, pcf2127_spi_id);
 440
 441 static struct spi_driver pcf2127_spi_driver = {
 442         .driver         = {
 443                 .name   = "rtc-pcf2127-spi",
 444                 .of_match_table = of_match_ptr(pcf2127_of_match),
 445         },
 446         .probe          = pcf2127_spi_probe,
 447         .id_table       = pcf2127_spi_id,
 448 };
 449
 450 static int pcf2127_spi_register_driver(void)
 451 {
 452         return spi_register_driver(&pcf2127_spi_driver);
 453 }
 454
 455 static void pcf2127_spi_unregister_driver(void)
 456 {
 457         spi_unregister_driver(&pcf2127_spi_driver);
 458 }
 459
 460 #else
 461
 462 static int pcf2127_spi_register_driver(void)
 463 {
 464         return 0;
 465 }
 466
 467 static void pcf2127_spi_unregister_driver(void)
 468 {
 469 }
 470
 471 #endif
 472
 473 static int __init pcf2127_init(void)
 474 {
 475         int ret;
 476
 477         ret = pcf2127_i2c_register_driver();
 478         if (ret) {
 479                 pr_err("Failed to register pcf2127 i2c driver: %d\n", ret);
 480                 return ret;
 481         }
 482
 483         ret = pcf2127_spi_register_driver();
 484         if (ret) {
 485                 pr_err("Failed to register pcf2127 spi driver: %d\n", ret);
 486                 pcf2127_i2c_unregister_driver();
 487         }
 488
 489         return ret;
 490 }
 491 module_init(pcf2127_init)
 492
 493 static void __exit pcf2127_exit(void)
 494 {
 495         pcf2127_spi_unregister_driver();
 496         pcf2127_i2c_unregister_driver();
 497 }
 498 module_exit(pcf2127_exit)
 499
 500 MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
 501 MODULE_DESCRIPTION("NXP PCF2127/29 RTC driver");
 502 MODULE_LICENSE("GPL v2");