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