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         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");