drivers/rtc/rtc-pcf2127.c

   1 /*
   2  * An I2C and SPI driver for the NXP PCF2127/29 RTC
   3  * Copyright 2013 Til-Technologies
   4  *
   5  * Author: Renaud Cerrato <r.cerrato@til-technologies.fr>
   6  *
   7  * based on the other drivers in this same directory.
   8  *
   9  * Datasheet: http://cache.nxp.com/documents/data_sheet/PCF2127.pdf
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  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
  25 #define PCF2127_REG_CTRL1       (0x00)  /* Control Register 1 */
  26 #define PCF2127_REG_CTRL2       (0x01)  /* Control Register 2 */
  27
  28 #define PCF2127_REG_CTRL3       (0x02)  /* Control Register 3 */
  29 #define PCF2127_REG_CTRL3_BLF           BIT(2)
  30
  31 #define PCF2127_REG_SC          (0x03)  /* datetime */
  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 /* the pcf2127 has 512 bytes nvmem, pcf2129 doesn't */
  40 #define PCF2127_REG_RAM_addr_MSB       0x1a
  41 #define PCF2127_REG_RAM_wrt_cmd        0x1c
  42 #define PCF2127_REG_RAM_rd_cmd         0x1d
  43
  44 #define PCF2127_OSF             BIT(7)  /* Oscillator Fail flag */
  45
  46 struct pcf2127 {
  47         struct rtc_device *rtc;
  48         struct regmap *regmap;
  49 };
  50
  51 /*
  52  * In the routines that deal directly with the pcf2127 hardware, we use
  53  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
  54  */
  55 static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm)
  56 {
  57         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
  58         unsigned char buf[10];
  59         int ret;
  60         int i;
  61
  62         for (i = 0; i <= PCF2127_REG_CTRL3; i++) {
  63                 ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL1 + i,
  64                                   (unsigned int *)(buf + i));
  65                 if (ret) {
  66                         dev_err(dev, "%s: read error\n", __func__);
  67                         return ret;
  68                 }
  69         }
  70
  71         ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_SC,
  72                                (buf + PCF2127_REG_SC),
  73                                ARRAY_SIZE(buf) - PCF2127_REG_SC);
  74         if (ret) {
  75                 dev_err(dev, "%s: read error\n", __func__);
  76                 return ret;
  77         }
  78
  79         if (buf[PCF2127_REG_CTRL3] & PCF2127_REG_CTRL3_BLF)
  80                 dev_info(dev,
  81                         "low voltage detected, check/replace RTC battery.\n");
  82
  83         if (buf[PCF2127_REG_SC] & PCF2127_OSF) {
  84                 /*
  85                  * no need clear the flag here,
  86                  * it will be cleared once the new date is saved
  87                  */
  88                 dev_warn(dev,
  89                          "oscillator stop detected, date/time is not reliable\n");
  90                 return -EINVAL;
  91         }
  92
  93         dev_dbg(dev,
  94                 "%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, "
  95                 "sec=%02x, min=%02x, hr=%02x, "
  96                 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
  97                 __func__,
  98                 buf[0], buf[1], buf[2],
  99                 buf[3], buf[4], buf[5],
 100                 buf[6], buf[7], buf[8], buf[9]);
 101
 102
 103         tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F);
 104         tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F);
 105         tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */
 106         tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F);
 107         tm->tm_wday = buf[PCF2127_REG_DW] & 0x07;
 108         tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
 109         tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]);
 110         if (tm->tm_year < 70)
 111                 tm->tm_year += 100;     /* assume we are in 1970...2069 */
 112
 113         dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 114                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 115                 __func__,
 116                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 117                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 118
 119         return 0;
 120 }
 121
 122 static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
 123 {
 124         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
 125         unsigned char buf[7];
 126         int i = 0, err;
 127
 128         dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "
 129                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 130                 __func__,
 131                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 132                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 133
 134         /* hours, minutes and seconds */
 135         buf[i++] = bin2bcd(tm->tm_sec); /* this will also clear OSF flag */
 136         buf[i++] = bin2bcd(tm->tm_min);
 137         buf[i++] = bin2bcd(tm->tm_hour);
 138         buf[i++] = bin2bcd(tm->tm_mday);
 139         buf[i++] = tm->tm_wday & 0x07;
 140
 141         /* month, 1 - 12 */
 142         buf[i++] = bin2bcd(tm->tm_mon + 1);
 143
 144         /* year */
 145         buf[i++] = bin2bcd(tm->tm_year % 100);
 146
 147         /* write register's data */
 148         err = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_SC, buf, i);
 149         if (err) {
 150                 dev_err(dev,
 151                         "%s: err=%d", __func__, err);
 152                 return err;
 153         }
 154
 155         return 0;
 156 }
 157
 158 #ifdef CONFIG_RTC_INTF_DEV
 159 static int pcf2127_rtc_ioctl(struct device *dev,
 160                                 unsigned int cmd, unsigned long arg)
 161 {
 162         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
 163         int touser;
 164         int ret;
 165
 166         switch (cmd) {
 167         case RTC_VL_READ:
 168                 ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &touser);
 169                 if (ret)
 170                         return ret;
 171
 172                 touser = touser & PCF2127_REG_CTRL3_BLF ? 1 : 0;
 173
 174                 if (copy_to_user((void __user *)arg, &touser, sizeof(int)))
 175                         return -EFAULT;
 176                 return 0;
 177         default:
 178                 return -ENOIOCTLCMD;
 179         }
 180 }
 181 #else
 182 #define pcf2127_rtc_ioctl NULL
 183 #endif
 184
 185 static const struct rtc_class_ops pcf2127_rtc_ops = {
 186         .ioctl          = pcf2127_rtc_ioctl,
 187         .read_time      = pcf2127_rtc_read_time,
 188         .set_time       = pcf2127_rtc_set_time,
 189 };
 190
 191 static int pcf2127_nvmem_read(void *priv, unsigned int offset,
 192                               void *val, size_t bytes)
 193 {
 194         struct pcf2127 *pcf2127 = priv;
 195         int ret;
 196         unsigned char offsetbuf[] = { offset >> 8, offset };
 197
 198         ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_addr_MSB,
 199                                 offsetbuf, 2);
 200         if (ret)
 201                 return ret;
 202
 203         ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_RAM_rd_cmd,
 204                                val, bytes);
 205
 206         return ret ?: bytes;
 207 }
 208
 209 static int pcf2127_nvmem_write(void *priv, unsigned int offset,
 210                                void *val, size_t bytes)
 211 {
 212         struct pcf2127 *pcf2127 = priv;
 213         int ret;
 214         unsigned char offsetbuf[] = { offset >> 8, offset };
 215
 216         ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_addr_MSB,
 217                                 offsetbuf, 2);
 218         if (ret)
 219                 return ret;
 220
 221         ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_wrt_cmd,
 222                                 val, bytes);
 223
 224         return ret ?: bytes;
 225 }
 226
 227 static int pcf2127_probe(struct device *dev, struct regmap *regmap,
 228                         const char *name, bool has_nvmem)
 229 {
 230         struct pcf2127 *pcf2127;
 231         int ret = 0;
 232
 233         dev_dbg(dev, "%s\n", __func__);
 234
 235         pcf2127 = devm_kzalloc(dev, sizeof(*pcf2127), GFP_KERNEL);
 236         if (!pcf2127)
 237                 return -ENOMEM;
 238
 239         pcf2127->regmap = regmap;
 240
 241         dev_set_drvdata(dev, pcf2127);
 242
 243         pcf2127->rtc = devm_rtc_device_register(dev, name, &pcf2127_rtc_ops,
 244                                                 THIS_MODULE);
 245         if (IS_ERR(pcf2127->rtc))
 246                 return PTR_ERR(pcf2127->rtc);
 247
 248         if (has_nvmem) {
 249                 struct nvmem_config nvmem_cfg = {
 250                         .priv = pcf2127,
 251                         .reg_read = pcf2127_nvmem_read,
 252                         .reg_write = pcf2127_nvmem_write,
 253                         .size = 512,
 254                 };
 255
 256                 ret = rtc_nvmem_register(pcf2127->rtc, &nvmem_cfg);
 257         }
 258
 259         return ret;
 260 }
 261
 262 #ifdef CONFIG_OF
 263 static const struct of_device_id pcf2127_of_match[] = {
 264         { .compatible = "nxp,pcf2127" },
 265         { .compatible = "nxp,pcf2129" },
 266         {}
 267 };
 268 MODULE_DEVICE_TABLE(of, pcf2127_of_match);
 269 #endif
 270
 271 #if IS_ENABLED(CONFIG_I2C)
 272
 273 static int pcf2127_i2c_write(void *context, const void *data, size_t count)
 274 {
 275         struct device *dev = context;
 276         struct i2c_client *client = to_i2c_client(dev);
 277         int ret;
 278
 279         ret = i2c_master_send(client, data, count);
 280         if (ret != count)
 281                 return ret < 0 ? ret : -EIO;
 282
 283         return 0;
 284 }
 285
 286 static int pcf2127_i2c_gather_write(void *context,
 287                                 const void *reg, size_t reg_size,
 288                                 const void *val, size_t val_size)
 289 {
 290         struct device *dev = context;
 291         struct i2c_client *client = to_i2c_client(dev);
 292         int ret;
 293         void *buf;
 294
 295         if (WARN_ON(reg_size != 1))
 296                 return -EINVAL;
 297
 298         buf = kmalloc(val_size + 1, GFP_KERNEL);
 299         if (!buf)
 300                 return -ENOMEM;
 301
 302         memcpy(buf, reg, 1);
 303         memcpy(buf + 1, val, val_size);
 304
 305         ret = i2c_master_send(client, buf, val_size + 1);
 306
 307         kfree(buf);
 308
 309         if (ret != val_size + 1)
 310                 return ret < 0 ? ret : -EIO;
 311
 312         return 0;
 313 }
 314
 315 static int pcf2127_i2c_read(void *context, const void *reg, size_t reg_size,
 316                                 void *val, size_t val_size)
 317 {
 318         struct device *dev = context;
 319         struct i2c_client *client = to_i2c_client(dev);
 320         int ret;
 321
 322         if (WARN_ON(reg_size != 1))
 323                 return -EINVAL;
 324
 325         ret = i2c_master_send(client, reg, 1);
 326         if (ret != 1)
 327                 return ret < 0 ? ret : -EIO;
 328
 329         ret = i2c_master_recv(client, val, val_size);
 330         if (ret != val_size)
 331                 return ret < 0 ? ret : -EIO;
 332
 333         return 0;
 334 }
 335
 336 /*
 337  * The reason we need this custom regmap_bus instead of using regmap_init_i2c()
 338  * is that the STOP condition is required between set register address and
 339  * read register data when reading from registers.
 340  */
 341 static const struct regmap_bus pcf2127_i2c_regmap = {
 342         .write = pcf2127_i2c_write,
 343         .gather_write = pcf2127_i2c_gather_write,
 344         .read = pcf2127_i2c_read,
 345 };
 346
 347 static struct i2c_driver pcf2127_i2c_driver;
 348
 349 static int pcf2127_i2c_probe(struct i2c_client *client,
 350                                 const struct i2c_device_id *id)
 351 {
 352         struct regmap *regmap;
 353         static const struct regmap_config config = {
 354                 .reg_bits = 8,
 355                 .val_bits = 8,
 356         };
 357
 358         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 359                 return -ENODEV;
 360
 361         regmap = devm_regmap_init(&client->dev, &pcf2127_i2c_regmap,
 362                                         &client->dev, &config);
 363         if (IS_ERR(regmap)) {
 364                 dev_err(&client->dev, "%s: regmap allocation failed: %ld\n",
 365                         __func__, PTR_ERR(regmap));
 366                 return PTR_ERR(regmap);
 367         }
 368
 369         return pcf2127_probe(&client->dev, regmap,
 370                              pcf2127_i2c_driver.driver.name, id->driver_data);
 371 }
 372
 373 static const struct i2c_device_id pcf2127_i2c_id[] = {
 374         { "pcf2127", 1 },
 375         { "pcf2129", 0 },
 376         { }
 377 };
 378 MODULE_DEVICE_TABLE(i2c, pcf2127_i2c_id);
 379
 380 static struct i2c_driver pcf2127_i2c_driver = {
 381         .driver         = {
 382                 .name   = "rtc-pcf2127-i2c",
 383                 .of_match_table = of_match_ptr(pcf2127_of_match),
 384         },
 385         .probe          = pcf2127_i2c_probe,
 386         .id_table       = pcf2127_i2c_id,
 387 };
 388
 389 static int pcf2127_i2c_register_driver(void)
 390 {
 391         return i2c_add_driver(&pcf2127_i2c_driver);
 392 }
 393
 394 static void pcf2127_i2c_unregister_driver(void)
 395 {
 396         i2c_del_driver(&pcf2127_i2c_driver);
 397 }
 398
 399 #else
 400
 401 static int pcf2127_i2c_register_driver(void)
 402 {
 403         return 0;
 404 }
 405
 406 static void pcf2127_i2c_unregister_driver(void)
 407 {
 408 }
 409
 410 #endif
 411
 412 #if IS_ENABLED(CONFIG_SPI_MASTER)
 413
 414 static struct spi_driver pcf2127_spi_driver;
 415
 416 static int pcf2127_spi_probe(struct spi_device *spi)
 417 {
 418         static const struct regmap_config config = {
 419                 .reg_bits = 8,
 420                 .val_bits = 8,
 421                 .read_flag_mask = 0xa0,
 422                 .write_flag_mask = 0x20,
 423         };
 424         struct regmap *regmap;
 425
 426         regmap = devm_regmap_init_spi(spi, &config);
 427         if (IS_ERR(regmap)) {
 428                 dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
 429                         __func__, PTR_ERR(regmap));
 430                 return PTR_ERR(regmap);
 431         }
 432
 433         return pcf2127_probe(&spi->dev, regmap, pcf2127_spi_driver.driver.name,
 434                              spi_get_device_id(spi)->driver_data);
 435 }
 436
 437 static const struct spi_device_id pcf2127_spi_id[] = {
 438         { "pcf2127", 1 },
 439         { "pcf2129", 0 },
 440         { }
 441 };
 442 MODULE_DEVICE_TABLE(spi, pcf2127_spi_id);
 443
 444 static struct spi_driver pcf2127_spi_driver = {
 445         .driver         = {
 446                 .name   = "rtc-pcf2127-spi",
 447                 .of_match_table = of_match_ptr(pcf2127_of_match),
 448         },
 449         .probe          = pcf2127_spi_probe,
 450         .id_table       = pcf2127_spi_id,
 451 };
 452
 453 static int pcf2127_spi_register_driver(void)
 454 {
 455         return spi_register_driver(&pcf2127_spi_driver);
 456 }
 457
 458 static void pcf2127_spi_unregister_driver(void)
 459 {
 460         spi_unregister_driver(&pcf2127_spi_driver);
 461 }
 462
 463 #else
 464
 465 static int pcf2127_spi_register_driver(void)
 466 {
 467         return 0;
 468 }
 469
 470 static void pcf2127_spi_unregister_driver(void)
 471 {
 472 }
 473
 474 #endif
 475
 476 static int __init pcf2127_init(void)
 477 {
 478         int ret;
 479
 480         ret = pcf2127_i2c_register_driver();
 481         if (ret) {
 482                 pr_err("Failed to register pcf2127 i2c driver: %d\n", ret);
 483                 return ret;
 484         }
 485
 486         ret = pcf2127_spi_register_driver();
 487         if (ret) {
 488                 pr_err("Failed to register pcf2127 spi driver: %d\n", ret);
 489                 pcf2127_i2c_unregister_driver();
 490         }
 491
 492         return ret;
 493 }
 494 module_init(pcf2127_init)
 495
 496 static void __exit pcf2127_exit(void)
 497 {
 498         pcf2127_spi_unregister_driver();
 499         pcf2127_i2c_unregister_driver();
 500 }
 501 module_exit(pcf2127_exit)
 502
 503 MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
 504 MODULE_DESCRIPTION("NXP PCF2127/29 RTC driver");
 505 MODULE_LICENSE("GPL v2");