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
  61         /*
  62          * Avoid reading CTRL2 register as it causes WD_VAL register
  63          * value to reset to 0 which means watchdog is stopped.
  64          */
  65         ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_CTRL3,
  66                                (buf + PCF2127_REG_CTRL3),
  67                                ARRAY_SIZE(buf) - PCF2127_REG_CTRL3);
  68         if (ret) {
  69                 dev_err(dev, "%s: read error\n", __func__);
  70                 return ret;
  71         }
  72
  73         if (buf[PCF2127_REG_CTRL3] & PCF2127_REG_CTRL3_BLF)
  74                 dev_info(dev,
  75                         "low voltage detected, check/replace RTC battery.\n");
  76
  77         if (buf[PCF2127_REG_SC] & PCF2127_OSF) {
  78                 /*
  79                  * no need clear the flag here,
  80                  * it will be cleared once the new date is saved
  81                  */
  82                 dev_warn(dev,
  83                          "oscillator stop detected, date/time is not reliable\n");
  84                 return -EINVAL;
  85         }
  86
  87         dev_dbg(dev,
  88                 "%s: raw data is cr3=%02x, sec=%02x, min=%02x, hr=%02x, "
  89                 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
  90                 __func__, buf[PCF2127_REG_CTRL3], buf[PCF2127_REG_SC],
  91                 buf[PCF2127_REG_MN], buf[PCF2127_REG_HR],
  92                 buf[PCF2127_REG_DM], buf[PCF2127_REG_DW],
  93                 buf[PCF2127_REG_MO], buf[PCF2127_REG_YR]);
  94
  95         tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F);
  96         tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F);
  97         tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */
  98         tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F);
  99         tm->tm_wday = buf[PCF2127_REG_DW] & 0x07;
 100         tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
 101         tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]);
 102         if (tm->tm_year < 70)
 103                 tm->tm_year += 100;     /* assume we are in 1970...2069 */
 104
 105         dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 106                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 107                 __func__,
 108                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 109                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 110
 111         return 0;
 112 }
 113
 114 static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
 115 {
 116         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
 117         unsigned char buf[7];
 118         int i = 0, err;
 119
 120         dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "
 121                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 122                 __func__,
 123                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 124                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 125
 126         /* hours, minutes and seconds */
 127         buf[i++] = bin2bcd(tm->tm_sec); /* this will also clear OSF flag */
 128         buf[i++] = bin2bcd(tm->tm_min);
 129         buf[i++] = bin2bcd(tm->tm_hour);
 130         buf[i++] = bin2bcd(tm->tm_mday);
 131         buf[i++] = tm->tm_wday & 0x07;
 132
 133         /* month, 1 - 12 */
 134         buf[i++] = bin2bcd(tm->tm_mon + 1);
 135
 136         /* year */
 137         buf[i++] = bin2bcd(tm->tm_year % 100);
 138
 139         /* write register's data */
 140         err = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_SC, buf, i);
 141         if (err) {
 142                 dev_err(dev,
 143                         "%s: err=%d", __func__, err);
 144                 return err;
 145         }
 146
 147         return 0;
 148 }
 149
 150 #ifdef CONFIG_RTC_INTF_DEV
 151 static int pcf2127_rtc_ioctl(struct device *dev,
 152                                 unsigned int cmd, unsigned long arg)
 153 {
 154         struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
 155         int touser;
 156         int ret;
 157
 158         switch (cmd) {
 159         case RTC_VL_READ:
 160                 ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &touser);
 161                 if (ret)
 162                         return ret;
 163
 164                 touser = touser & PCF2127_REG_CTRL3_BLF ? 1 : 0;
 165
 166                 if (copy_to_user((void __user *)arg, &touser, sizeof(int)))
 167                         return -EFAULT;
 168                 return 0;
 169         default:
 170                 return -ENOIOCTLCMD;
 171         }
 172 }
 173 #else
 174 #define pcf2127_rtc_ioctl NULL
 175 #endif
 176
 177 static const struct rtc_class_ops pcf2127_rtc_ops = {
 178         .ioctl          = pcf2127_rtc_ioctl,
 179         .read_time      = pcf2127_rtc_read_time,
 180         .set_time       = pcf2127_rtc_set_time,
 181 };
 182
 183 static int pcf2127_nvmem_read(void *priv, unsigned int offset,
 184                               void *val, size_t bytes)
 185 {
 186         struct pcf2127 *pcf2127 = priv;
 187         int ret;
 188         unsigned char offsetbuf[] = { offset >> 8, offset };
 189
 190         ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_addr_MSB,
 191                                 offsetbuf, 2);
 192         if (ret)
 193                 return ret;
 194
 195         ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_RAM_rd_cmd,
 196                                val, bytes);
 197
 198         return ret ?: bytes;
 199 }
 200
 201 static int pcf2127_nvmem_write(void *priv, unsigned int offset,
 202                                void *val, size_t bytes)
 203 {
 204         struct pcf2127 *pcf2127 = priv;
 205         int ret;
 206         unsigned char offsetbuf[] = { offset >> 8, offset };
 207
 208         ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_addr_MSB,
 209                                 offsetbuf, 2);
 210         if (ret)
 211                 return ret;
 212
 213         ret = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_RAM_wrt_cmd,
 214                                 val, bytes);
 215
 216         return ret ?: bytes;
 217 }
 218
 219 static int pcf2127_probe(struct device *dev, struct regmap *regmap,
 220                         const char *name, bool has_nvmem)
 221 {
 222         struct pcf2127 *pcf2127;
 223         int ret = 0;
 224
 225         dev_dbg(dev, "%s\n", __func__);
 226
 227         pcf2127 = devm_kzalloc(dev, sizeof(*pcf2127), GFP_KERNEL);
 228         if (!pcf2127)
 229                 return -ENOMEM;
 230
 231         pcf2127->regmap = regmap;
 232
 233         dev_set_drvdata(dev, pcf2127);
 234
 235         pcf2127->rtc = devm_rtc_device_register(dev, name, &pcf2127_rtc_ops,
 236                                                 THIS_MODULE);
 237         if (IS_ERR(pcf2127->rtc))
 238                 return PTR_ERR(pcf2127->rtc);
 239
 240         if (has_nvmem) {
 241                 struct nvmem_config nvmem_cfg = {
 242                         .priv = pcf2127,
 243                         .reg_read = pcf2127_nvmem_read,
 244                         .reg_write = pcf2127_nvmem_write,
 245                         .size = 512,
 246                 };
 247
 248                 ret = rtc_nvmem_register(pcf2127->rtc, &nvmem_cfg);
 249         }
 250
 251         return ret;
 252 }
 253
 254 #ifdef CONFIG_OF
 255 static const struct of_device_id pcf2127_of_match[] = {
 256         { .compatible = "nxp,pcf2127" },
 257         { .compatible = "nxp,pcf2129" },
 258         {}
 259 };
 260 MODULE_DEVICE_TABLE(of, pcf2127_of_match);
 261 #endif
 262
 263 #if IS_ENABLED(CONFIG_I2C)
 264
 265 static int pcf2127_i2c_write(void *context, const void *data, size_t count)
 266 {
 267         struct device *dev = context;
 268         struct i2c_client *client = to_i2c_client(dev);
 269         int ret;
 270
 271         ret = i2c_master_send(client, data, count);
 272         if (ret != count)
 273                 return ret < 0 ? ret : -EIO;
 274
 275         return 0;
 276 }
 277
 278 static int pcf2127_i2c_gather_write(void *context,
 279                                 const void *reg, size_t reg_size,
 280                                 const void *val, size_t val_size)
 281 {
 282         struct device *dev = context;
 283         struct i2c_client *client = to_i2c_client(dev);
 284         int ret;
 285         void *buf;
 286
 287         if (WARN_ON(reg_size != 1))
 288                 return -EINVAL;
 289
 290         buf = kmalloc(val_size + 1, GFP_KERNEL);
 291         if (!buf)
 292                 return -ENOMEM;
 293
 294         memcpy(buf, reg, 1);
 295         memcpy(buf + 1, val, val_size);
 296
 297         ret = i2c_master_send(client, buf, val_size + 1);
 298
 299         kfree(buf);
 300
 301         if (ret != val_size + 1)
 302                 return ret < 0 ? ret : -EIO;
 303
 304         return 0;
 305 }
 306
 307 static int pcf2127_i2c_read(void *context, const void *reg, size_t reg_size,
 308                                 void *val, size_t val_size)
 309 {
 310         struct device *dev = context;
 311         struct i2c_client *client = to_i2c_client(dev);
 312         int ret;
 313
 314         if (WARN_ON(reg_size != 1))
 315                 return -EINVAL;
 316
 317         ret = i2c_master_send(client, reg, 1);
 318         if (ret != 1)
 319                 return ret < 0 ? ret : -EIO;
 320
 321         ret = i2c_master_recv(client, val, val_size);
 322         if (ret != val_size)
 323                 return ret < 0 ? ret : -EIO;
 324
 325         return 0;
 326 }
 327
 328 /*
 329  * The reason we need this custom regmap_bus instead of using regmap_init_i2c()
 330  * is that the STOP condition is required between set register address and
 331  * read register data when reading from registers.
 332  */
 333 static const struct regmap_bus pcf2127_i2c_regmap = {
 334         .write = pcf2127_i2c_write,
 335         .gather_write = pcf2127_i2c_gather_write,
 336         .read = pcf2127_i2c_read,
 337 };
 338
 339 static struct i2c_driver pcf2127_i2c_driver;
 340
 341 static int pcf2127_i2c_probe(struct i2c_client *client,
 342                                 const struct i2c_device_id *id)
 343 {
 344         struct regmap *regmap;
 345         static const struct regmap_config config = {
 346                 .reg_bits = 8,
 347                 .val_bits = 8,
 348         };
 349
 350         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 351                 return -ENODEV;
 352
 353         regmap = devm_regmap_init(&client->dev, &pcf2127_i2c_regmap,
 354                                         &client->dev, &config);
 355         if (IS_ERR(regmap)) {
 356                 dev_err(&client->dev, "%s: regmap allocation failed: %ld\n",
 357                         __func__, PTR_ERR(regmap));
 358                 return PTR_ERR(regmap);
 359         }
 360
 361         return pcf2127_probe(&client->dev, regmap,
 362                              pcf2127_i2c_driver.driver.name, id->driver_data);
 363 }
 364
 365 static const struct i2c_device_id pcf2127_i2c_id[] = {
 366         { "pcf2127", 1 },
 367         { "pcf2129", 0 },
 368         { }
 369 };
 370 MODULE_DEVICE_TABLE(i2c, pcf2127_i2c_id);
 371
 372 static struct i2c_driver pcf2127_i2c_driver = {
 373         .driver         = {
 374                 .name   = "rtc-pcf2127-i2c",
 375                 .of_match_table = of_match_ptr(pcf2127_of_match),
 376         },
 377         .probe          = pcf2127_i2c_probe,
 378         .id_table       = pcf2127_i2c_id,
 379 };
 380
 381 static int pcf2127_i2c_register_driver(void)
 382 {
 383         return i2c_add_driver(&pcf2127_i2c_driver);
 384 }
 385
 386 static void pcf2127_i2c_unregister_driver(void)
 387 {
 388         i2c_del_driver(&pcf2127_i2c_driver);
 389 }
 390
 391 #else
 392
 393 static int pcf2127_i2c_register_driver(void)
 394 {
 395         return 0;
 396 }
 397
 398 static void pcf2127_i2c_unregister_driver(void)
 399 {
 400 }
 401
 402 #endif
 403
 404 #if IS_ENABLED(CONFIG_SPI_MASTER)
 405
 406 static struct spi_driver pcf2127_spi_driver;
 407
 408 static int pcf2127_spi_probe(struct spi_device *spi)
 409 {
 410         static const struct regmap_config config = {
 411                 .reg_bits = 8,
 412                 .val_bits = 8,
 413                 .read_flag_mask = 0xa0,
 414                 .write_flag_mask = 0x20,
 415         };
 416         struct regmap *regmap;
 417
 418         regmap = devm_regmap_init_spi(spi, &config);
 419         if (IS_ERR(regmap)) {
 420                 dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
 421                         __func__, PTR_ERR(regmap));
 422                 return PTR_ERR(regmap);
 423         }
 424
 425         return pcf2127_probe(&spi->dev, regmap, pcf2127_spi_driver.driver.name,
 426                              spi_get_device_id(spi)->driver_data);
 427 }
 428
 429 static const struct spi_device_id pcf2127_spi_id[] = {
 430         { "pcf2127", 1 },
 431         { "pcf2129", 0 },
 432         { }
 433 };
 434 MODULE_DEVICE_TABLE(spi, pcf2127_spi_id);
 435
 436 static struct spi_driver pcf2127_spi_driver = {
 437         .driver         = {
 438                 .name   = "rtc-pcf2127-spi",
 439                 .of_match_table = of_match_ptr(pcf2127_of_match),
 440         },
 441         .probe          = pcf2127_spi_probe,
 442         .id_table       = pcf2127_spi_id,
 443 };
 444
 445 static int pcf2127_spi_register_driver(void)
 446 {
 447         return spi_register_driver(&pcf2127_spi_driver);
 448 }
 449
 450 static void pcf2127_spi_unregister_driver(void)
 451 {
 452         spi_unregister_driver(&pcf2127_spi_driver);
 453 }
 454
 455 #else
 456
 457 static int pcf2127_spi_register_driver(void)
 458 {
 459         return 0;
 460 }
 461
 462 static void pcf2127_spi_unregister_driver(void)
 463 {
 464 }
 465
 466 #endif
 467
 468 static int __init pcf2127_init(void)
 469 {
 470         int ret;
 471
 472         ret = pcf2127_i2c_register_driver();
 473         if (ret) {
 474                 pr_err("Failed to register pcf2127 i2c driver: %d\n", ret);
 475                 return ret;
 476         }
 477
 478         ret = pcf2127_spi_register_driver();
 479         if (ret) {
 480                 pr_err("Failed to register pcf2127 spi driver: %d\n", ret);
 481                 pcf2127_i2c_unregister_driver();
 482         }
 483
 484         return ret;
 485 }
 486 module_init(pcf2127_init)
 487
 488 static void __exit pcf2127_exit(void)
 489 {
 490         pcf2127_spi_unregister_driver();
 491         pcf2127_i2c_unregister_driver();
 492 }
 493 module_exit(pcf2127_exit)
 494
 495 MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
 496 MODULE_DESCRIPTION("NXP PCF2127/29 RTC driver");
 497 MODULE_LICENSE("GPL v2");