drivers/rtc/rtc-pcf2127.c

   1 /*
   2  * An I2C and SPI driver for the NXP PCF2127 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  * http://www.nxp.com/documents/data_sheet/PCF2127AT.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         {}
 200 };
 201 MODULE_DEVICE_TABLE(of, pcf2127_of_match);
 202 #endif
 203
 204 #if IS_ENABLED(CONFIG_I2C)
 205
 206 static int pcf2127_i2c_write(void *context, const void *data, size_t count)
 207 {
 208         struct device *dev = context;
 209         struct i2c_client *client = to_i2c_client(dev);
 210         int ret;
 211
 212         ret = i2c_master_send(client, data, count);
 213         if (ret != count)
 214                 return ret < 0 ? ret : -EIO;
 215
 216         return 0;
 217 }
 218
 219 static int pcf2127_i2c_gather_write(void *context,
 220                                 const void *reg, size_t reg_size,
 221                                 const void *val, size_t val_size)
 222 {
 223         struct device *dev = context;
 224         struct i2c_client *client = to_i2c_client(dev);
 225         int ret;
 226         void *buf;
 227
 228         if (WARN_ON(reg_size != 1))
 229                 return -EINVAL;
 230
 231         buf = kmalloc(val_size + 1, GFP_KERNEL);
 232         if (!buf)
 233                 return -ENOMEM;
 234
 235         memcpy(buf, reg, 1);
 236         memcpy(buf + 1, val, val_size);
 237
 238         ret = i2c_master_send(client, buf, val_size + 1);
 239         if (ret != val_size + 1)
 240                 return ret < 0 ? ret : -EIO;
 241
 242         return 0;
 243 }
 244
 245 static int pcf2127_i2c_read(void *context, const void *reg, size_t reg_size,
 246                                 void *val, size_t val_size)
 247 {
 248         struct device *dev = context;
 249         struct i2c_client *client = to_i2c_client(dev);
 250         int ret;
 251
 252         if (WARN_ON(reg_size != 1))
 253                 return -EINVAL;
 254
 255         ret = i2c_master_send(client, reg, 1);
 256         if (ret != 1)
 257                 return ret < 0 ? ret : -EIO;
 258
 259         ret = i2c_master_recv(client, val, val_size);
 260         if (ret != val_size)
 261                 return ret < 0 ? ret : -EIO;
 262
 263         return 0;
 264 }
 265
 266 /*
 267  * The reason we need this custom regmap_bus instead of using regmap_init_i2c()
 268  * is that the STOP condition is required between set register address and
 269  * read register data when reading from registers.
 270  */
 271 static const struct regmap_bus pcf2127_i2c_regmap = {
 272         .write = pcf2127_i2c_write,
 273         .gather_write = pcf2127_i2c_gather_write,
 274         .read = pcf2127_i2c_read,
 275 };
 276
 277 static struct i2c_driver pcf2127_i2c_driver;
 278
 279 static int pcf2127_i2c_probe(struct i2c_client *client,
 280                                 const struct i2c_device_id *id)
 281 {
 282         struct regmap *regmap;
 283         static const struct regmap_config config = {
 284                 .reg_bits = 8,
 285                 .val_bits = 8,
 286         };
 287
 288         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 289                 return -ENODEV;
 290
 291         regmap = devm_regmap_init(&client->dev, &pcf2127_i2c_regmap,
 292                                         &client->dev, &config);
 293         if (IS_ERR(regmap)) {
 294                 dev_err(&client->dev, "%s: regmap allocation failed: %ld\n",
 295                         __func__, PTR_ERR(regmap));
 296                 return PTR_ERR(regmap);
 297         }
 298
 299         return pcf2127_probe(&client->dev, regmap,
 300                                 pcf2127_i2c_driver.driver.name);
 301 }
 302
 303 static const struct i2c_device_id pcf2127_i2c_id[] = {
 304         { "pcf2127", 0 },
 305         { }
 306 };
 307 MODULE_DEVICE_TABLE(i2c, pcf2127_i2c_id);
 308
 309 static struct i2c_driver pcf2127_i2c_driver = {
 310         .driver         = {
 311                 .name   = "rtc-pcf2127-i2c",
 312                 .of_match_table = of_match_ptr(pcf2127_of_match),
 313         },
 314         .probe          = pcf2127_i2c_probe,
 315         .id_table       = pcf2127_i2c_id,
 316 };
 317
 318 static int pcf2127_i2c_register_driver(void)
 319 {
 320         return i2c_add_driver(&pcf2127_i2c_driver);
 321 }
 322
 323 static void pcf2127_i2c_unregister_driver(void)
 324 {
 325         i2c_del_driver(&pcf2127_i2c_driver);
 326 }
 327
 328 #else
 329
 330 static int pcf2127_i2c_register_driver(void)
 331 {
 332         return 0;
 333 }
 334
 335 static void pcf2127_i2c_unregister_driver(void)
 336 {
 337 }
 338
 339 #endif
 340
 341 #if IS_ENABLED(CONFIG_SPI_MASTER)
 342
 343 static struct spi_driver pcf2127_spi_driver;
 344
 345 static int pcf2127_spi_probe(struct spi_device *spi)
 346 {
 347         static const struct regmap_config config = {
 348                 .reg_bits = 8,
 349                 .val_bits = 8,
 350                 .read_flag_mask = 0xa0,
 351                 .write_flag_mask = 0x20,
 352         };
 353         struct regmap *regmap;
 354
 355         regmap = devm_regmap_init_spi(spi, &config);
 356         if (IS_ERR(regmap)) {
 357                 dev_err(&spi->dev, "%s: regmap allocation failed: %ld\n",
 358                         __func__, PTR_ERR(regmap));
 359                 return PTR_ERR(regmap);
 360         }
 361
 362         return pcf2127_probe(&spi->dev, regmap, pcf2127_spi_driver.driver.name);
 363 }
 364
 365 static const struct spi_device_id pcf2127_spi_id[] = {
 366         { "pcf2127", 0 },
 367         { }
 368 };
 369 MODULE_DEVICE_TABLE(spi, pcf2127_spi_id);
 370
 371 static struct spi_driver pcf2127_spi_driver = {
 372         .driver         = {
 373                 .name   = "rtc-pcf2127-spi",
 374                 .of_match_table = of_match_ptr(pcf2127_of_match),
 375         },
 376         .probe          = pcf2127_spi_probe,
 377         .id_table       = pcf2127_spi_id,
 378 };
 379
 380 static int pcf2127_spi_register_driver(void)
 381 {
 382         return spi_register_driver(&pcf2127_spi_driver);
 383 }
 384
 385 static void pcf2127_spi_unregister_driver(void)
 386 {
 387         spi_unregister_driver(&pcf2127_spi_driver);
 388 }
 389
 390 #else
 391
 392 static int pcf2127_spi_register_driver(void)
 393 {
 394         return 0;
 395 }
 396
 397 static void pcf2127_spi_unregister_driver(void)
 398 {
 399 }
 400
 401 #endif
 402
 403 static int __init pcf2127_init(void)
 404 {
 405         int ret;
 406
 407         ret = pcf2127_i2c_register_driver();
 408         if (ret) {
 409                 pr_err("Failed to register pcf2127 i2c driver: %d\n", ret);
 410                 return ret;
 411         }
 412
 413         ret = pcf2127_spi_register_driver();
 414         if (ret) {
 415                 pr_err("Failed to register pcf2127 spi driver: %d\n", ret);
 416                 pcf2127_i2c_unregister_driver();
 417         }
 418
 419         return ret;
 420 }
 421 module_init(pcf2127_init)
 422
 423 static void __exit pcf2127_exit(void)
 424 {
 425         pcf2127_spi_unregister_driver();
 426         pcf2127_i2c_unregister_driver();
 427 }
 428 module_exit(pcf2127_exit)
 429
 430 MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
 431 MODULE_DESCRIPTION("NXP PCF2127 RTC driver");
 432 MODULE_LICENSE("GPL v2");