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