drivers/rtc/rtc-s35390a.c

   1 /*
   2  * Seiko Instruments S-35390A RTC Driver
   3  *
   4  * Copyright (c) 2007 Byron Bradley
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/rtc.h>
  14 #include <linux/i2c.h>
  15 #include <linux/bitrev.h>
  16 #include <linux/bcd.h>
  17 #include <linux/slab.h>
  18 #include <linux/delay.h>
  19
  20 #define S35390A_CMD_STATUS1     0
  21 #define S35390A_CMD_STATUS2     1
  22 #define S35390A_CMD_TIME1       2
  23 #define S35390A_CMD_TIME2       3
  24 #define S35390A_CMD_INT2_REG1   5
  25
  26 #define S35390A_BYTE_YEAR       0
  27 #define S35390A_BYTE_MONTH      1
  28 #define S35390A_BYTE_DAY        2
  29 #define S35390A_BYTE_WDAY       3
  30 #define S35390A_BYTE_HOURS      4
  31 #define S35390A_BYTE_MINS       5
  32 #define S35390A_BYTE_SECS       6
  33
  34 #define S35390A_ALRM_BYTE_WDAY  0
  35 #define S35390A_ALRM_BYTE_HOURS 1
  36 #define S35390A_ALRM_BYTE_MINS  2
  37
  38 /* flags for STATUS1 */
  39 #define S35390A_FLAG_POC        0x01
  40 #define S35390A_FLAG_BLD        0x02
  41 #define S35390A_FLAG_INT2       0x04
  42 #define S35390A_FLAG_24H        0x40
  43 #define S35390A_FLAG_RESET      0x80
  44
  45 /* flag for STATUS2 */
  46 #define S35390A_FLAG_TEST       0x01
  47
  48 #define S35390A_INT2_MODE_MASK          0xF0
  49
  50 #define S35390A_INT2_MODE_NOINTR        0x00
  51 #define S35390A_INT2_MODE_FREQ          0x10
  52 #define S35390A_INT2_MODE_ALARM         0x40
  53 #define S35390A_INT2_MODE_PMIN_EDG      0x20
  54
  55 static const struct i2c_device_id s35390a_id[] = {
  56         { "s35390a", 0 },
  57         { }
  58 };
  59 MODULE_DEVICE_TABLE(i2c, s35390a_id);
  60
  61 static const struct of_device_id s35390a_of_match[] = {
  62         { .compatible = "s35390a" },
  63         { .compatible = "sii,s35390a" },
  64         { }
  65 };
  66 MODULE_DEVICE_TABLE(of, s35390a_of_match);
  67
  68 struct s35390a {
  69         struct i2c_client *client[8];
  70         struct rtc_device *rtc;
  71         int twentyfourhour;
  72 };
  73
  74 static int s35390a_set_reg(struct s35390a *s35390a, int reg, char *buf, int len)
  75 {
  76         struct i2c_client *client = s35390a->client[reg];
  77         struct i2c_msg msg[] = {
  78                 {
  79                         .addr = client->addr,
  80                         .len = len,
  81                         .buf = buf
  82                 },
  83         };
  84
  85         if ((i2c_transfer(client->adapter, msg, 1)) != 1)
  86                 return -EIO;
  87
  88         return 0;
  89 }
  90
  91 static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len)
  92 {
  93         struct i2c_client *client = s35390a->client[reg];
  94         struct i2c_msg msg[] = {
  95                 {
  96                         .addr = client->addr,
  97                         .flags = I2C_M_RD,
  98                         .len = len,
  99                         .buf = buf
 100                 },
 101         };
 102
 103         if ((i2c_transfer(client->adapter, msg, 1)) != 1)
 104                 return -EIO;
 105
 106         return 0;
 107 }
 108
 109 static int s35390a_init(struct s35390a *s35390a)
 110 {
 111         char buf;
 112         int ret;
 113         unsigned initcount = 0;
 114
 115         /*
 116          * At least one of POC and BLD are set, so reinitialise chip. Keeping
 117          * this information in the hardware to know later that the time isn't
 118          * valid is unfortunately not possible because POC and BLD are cleared
 119          * on read. So the reset is best done now.
 120          *
 121          * The 24H bit is kept over reset, so set it already here.
 122          */
 123 initialize:
 124         buf = S35390A_FLAG_RESET | S35390A_FLAG_24H;
 125         ret = s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
 126
 127         if (ret < 0)
 128                 return ret;
 129
 130         ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
 131         if (ret < 0)
 132                 return ret;
 133
 134         if (buf & (S35390A_FLAG_POC | S35390A_FLAG_BLD)) {
 135                 /* Try up to five times to reset the chip */
 136                 if (initcount < 5) {
 137                         ++initcount;
 138                         goto initialize;
 139                 } else
 140                         return -EIO;
 141         }
 142
 143         return 1;
 144 }
 145
 146 /*
 147  * Returns <0 on error, 0 if rtc is setup fine and 1 if the chip was reset.
 148  * To keep the information if an irq is pending, pass the value read from
 149  * STATUS1 to the caller.
 150  */
 151 static int s35390a_read_status(struct s35390a *s35390a, char *status1)
 152 {
 153         int ret;
 154
 155         ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, status1, 1);
 156         if (ret < 0)
 157                 return ret;
 158
 159         if (*status1 & S35390A_FLAG_POC) {
 160                 /*
 161                  * Do not communicate for 0.5 seconds since the power-on
 162                  * detection circuit is in operation.
 163                  */
 164                 msleep(500);
 165                 return 1;
 166         } else if (*status1 & S35390A_FLAG_BLD)
 167                 return 1;
 168         /*
 169          * If both POC and BLD are unset everything is fine.
 170          */
 171         return 0;
 172 }
 173
 174 static int s35390a_disable_test_mode(struct s35390a *s35390a)
 175 {
 176         char buf[1];
 177
 178         if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0)
 179                 return -EIO;
 180
 181         if (!(buf[0] & S35390A_FLAG_TEST))
 182                 return 0;
 183
 184         buf[0] &= ~S35390A_FLAG_TEST;
 185         return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf));
 186 }
 187
 188 static char s35390a_hr2reg(struct s35390a *s35390a, int hour)
 189 {
 190         if (s35390a->twentyfourhour)
 191                 return bin2bcd(hour);
 192
 193         if (hour < 12)
 194                 return bin2bcd(hour);
 195
 196         return 0x40 | bin2bcd(hour - 12);
 197 }
 198
 199 static int s35390a_reg2hr(struct s35390a *s35390a, char reg)
 200 {
 201         unsigned hour;
 202
 203         if (s35390a->twentyfourhour)
 204                 return bcd2bin(reg & 0x3f);
 205
 206         hour = bcd2bin(reg & 0x3f);
 207         if (reg & 0x40)
 208                 hour += 12;
 209
 210         return hour;
 211 }
 212
 213 static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 214 {
 215         struct s35390a  *s35390a = i2c_get_clientdata(client);
 216         int i, err;
 217         char buf[7], status;
 218
 219         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, "
 220                 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
 221                 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
 222                 tm->tm_wday);
 223
 224         if (s35390a_read_status(s35390a, &status) == 1)
 225                 s35390a_init(s35390a);
 226
 227         buf[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 100);
 228         buf[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon + 1);
 229         buf[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday);
 230         buf[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday);
 231         buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour);
 232         buf[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min);
 233         buf[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec);
 234
 235         /* This chip expects the bits of each byte to be in reverse order */
 236         for (i = 0; i < 7; ++i)
 237                 buf[i] = bitrev8(buf[i]);
 238
 239         err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
 240
 241         return err;
 242 }
 243
 244 static int s35390a_get_datetime(struct i2c_client *client, struct rtc_time *tm)
 245 {
 246         struct s35390a *s35390a = i2c_get_clientdata(client);
 247         char buf[7], status;
 248         int i, err;
 249
 250         if (s35390a_read_status(s35390a, &status) == 1)
 251                 return -EINVAL;
 252
 253         err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
 254         if (err < 0)
 255                 return err;
 256
 257         /* This chip returns the bits of each byte in reverse order */
 258         for (i = 0; i < 7; ++i)
 259                 buf[i] = bitrev8(buf[i]);
 260
 261         tm->tm_sec = bcd2bin(buf[S35390A_BYTE_SECS]);
 262         tm->tm_min = bcd2bin(buf[S35390A_BYTE_MINS]);
 263         tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]);
 264         tm->tm_wday = bcd2bin(buf[S35390A_BYTE_WDAY]);
 265         tm->tm_mday = bcd2bin(buf[S35390A_BYTE_DAY]);
 266         tm->tm_mon = bcd2bin(buf[S35390A_BYTE_MONTH]) - 1;
 267         tm->tm_year = bcd2bin(buf[S35390A_BYTE_YEAR]) + 100;
 268
 269         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, "
 270                 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
 271                 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
 272                 tm->tm_wday);
 273
 274         return rtc_valid_tm(tm);
 275 }
 276
 277 static int s35390a_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
 278 {
 279         struct s35390a *s35390a = i2c_get_clientdata(client);
 280         char buf[3], sts = 0;
 281         int err, i;
 282
 283         dev_dbg(&client->dev, "%s: alm is secs=%d, mins=%d, hours=%d mday=%d, "\
 284                 "mon=%d, year=%d, wday=%d\n", __func__, alm->time.tm_sec,
 285                 alm->time.tm_min, alm->time.tm_hour, alm->time.tm_mday,
 286                 alm->time.tm_mon, alm->time.tm_year, alm->time.tm_wday);
 287
 288         /* disable interrupt (which deasserts the irq line) */
 289         err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
 290         if (err < 0)
 291                 return err;
 292
 293         /* clear pending interrupt (in STATUS1 only), if any */
 294         err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &sts, sizeof(sts));
 295         if (err < 0)
 296                 return err;
 297
 298         if (alm->enabled)
 299                 sts = S35390A_INT2_MODE_ALARM;
 300         else
 301                 sts = S35390A_INT2_MODE_NOINTR;
 302
 303         /* This chip expects the bits of each byte to be in reverse order */
 304         sts = bitrev8(sts);
 305
 306         /* set interupt mode*/
 307         err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
 308         if (err < 0)
 309                 return err;
 310
 311         if (alm->time.tm_wday != -1)
 312                 buf[S35390A_ALRM_BYTE_WDAY] = bin2bcd(alm->time.tm_wday) | 0x80;
 313         else
 314                 buf[S35390A_ALRM_BYTE_WDAY] = 0;
 315
 316         buf[S35390A_ALRM_BYTE_HOURS] = s35390a_hr2reg(s35390a,
 317                         alm->time.tm_hour) | 0x80;
 318         buf[S35390A_ALRM_BYTE_MINS] = bin2bcd(alm->time.tm_min) | 0x80;
 319
 320         if (alm->time.tm_hour >= 12)
 321                 buf[S35390A_ALRM_BYTE_HOURS] |= 0x40;
 322
 323         for (i = 0; i < 3; ++i)
 324                 buf[i] = bitrev8(buf[i]);
 325
 326         err = s35390a_set_reg(s35390a, S35390A_CMD_INT2_REG1, buf,
 327                                                                 sizeof(buf));
 328
 329         return err;
 330 }
 331
 332 static int s35390a_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
 333 {
 334         struct s35390a *s35390a = i2c_get_clientdata(client);
 335         char buf[3], sts;
 336         int i, err;
 337
 338         err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
 339         if (err < 0)
 340                 return err;
 341
 342         if ((bitrev8(sts) & S35390A_INT2_MODE_MASK) != S35390A_INT2_MODE_ALARM) {
 343                 /*
 344                  * When the alarm isn't enabled, the register to configure
 345                  * the alarm time isn't accessible.
 346                  */
 347                 alm->enabled = 0;
 348                 return 0;
 349         } else {
 350                 alm->enabled = 1;
 351         }
 352
 353         err = s35390a_get_reg(s35390a, S35390A_CMD_INT2_REG1, buf, sizeof(buf));
 354         if (err < 0)
 355                 return err;
 356
 357         /* This chip returns the bits of each byte in reverse order */
 358         for (i = 0; i < 3; ++i)
 359                 buf[i] = bitrev8(buf[i]);
 360
 361         /*
 362          * B0 of the three matching registers is an enable flag. Iff it is set
 363          * the configured value is used for matching.
 364          */
 365         if (buf[S35390A_ALRM_BYTE_WDAY] & 0x80)
 366                 alm->time.tm_wday =
 367                         bcd2bin(buf[S35390A_ALRM_BYTE_WDAY] & ~0x80);
 368
 369         if (buf[S35390A_ALRM_BYTE_HOURS] & 0x80)
 370                 alm->time.tm_hour =
 371                         s35390a_reg2hr(s35390a,
 372                                        buf[S35390A_ALRM_BYTE_HOURS] & ~0x80);
 373
 374         if (buf[S35390A_ALRM_BYTE_MINS] & 0x80)
 375                 alm->time.tm_min = bcd2bin(buf[S35390A_ALRM_BYTE_MINS] & ~0x80);
 376
 377         /* alarm triggers always at s=0 */
 378         alm->time.tm_sec = 0;
 379
 380         dev_dbg(&client->dev, "%s: alm is mins=%d, hours=%d, wday=%d\n",
 381                         __func__, alm->time.tm_min, alm->time.tm_hour,
 382                         alm->time.tm_wday);
 383
 384         return 0;
 385 }
 386
 387 static int s35390a_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 388 {
 389         return s35390a_read_alarm(to_i2c_client(dev), alm);
 390 }
 391
 392 static int s35390a_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 393 {
 394         return s35390a_set_alarm(to_i2c_client(dev), alm);
 395 }
 396
 397 static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm)
 398 {
 399         return s35390a_get_datetime(to_i2c_client(dev), tm);
 400 }
 401
 402 static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)
 403 {
 404         return s35390a_set_datetime(to_i2c_client(dev), tm);
 405 }
 406
 407 static int s35390a_rtc_ioctl(struct device *dev, unsigned int cmd,
 408                              unsigned long arg)
 409 {
 410         struct i2c_client *client = to_i2c_client(dev);
 411         struct s35390a *s35390a = i2c_get_clientdata(client);
 412         char sts;
 413         int err;
 414
 415         switch (cmd) {
 416         case RTC_VL_READ:
 417                 /* s35390a_reset set lowvoltage flag and init RTC if needed */
 418                 err = s35390a_read_status(s35390a, &sts);
 419                 if (err < 0)
 420                         return err;
 421                 if (copy_to_user((void __user *)arg, &err, sizeof(int)))
 422                         return -EFAULT;
 423                 break;
 424         case RTC_VL_CLR:
 425                 /* update flag and clear register */
 426                 err = s35390a_init(s35390a);
 427                 if (err < 0)
 428                         return err;
 429                 break;
 430         default:
 431                 return -ENOIOCTLCMD;
 432         }
 433
 434         return 0;
 435 }
 436
 437 static const struct rtc_class_ops s35390a_rtc_ops = {
 438         .read_time      = s35390a_rtc_read_time,
 439         .set_time       = s35390a_rtc_set_time,
 440         .set_alarm      = s35390a_rtc_set_alarm,
 441         .read_alarm     = s35390a_rtc_read_alarm,
 442         .ioctl          = s35390a_rtc_ioctl,
 443 };
 444
 445 static struct i2c_driver s35390a_driver;
 446
 447 static int s35390a_probe(struct i2c_client *client,
 448                          const struct i2c_device_id *id)
 449 {
 450         int err, err_read;
 451         unsigned int i;
 452         struct s35390a *s35390a;
 453         struct rtc_time tm;
 454         char buf, status1;
 455
 456         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 457                 err = -ENODEV;
 458                 goto exit;
 459         }
 460
 461         s35390a = devm_kzalloc(&client->dev, sizeof(struct s35390a),
 462                                 GFP_KERNEL);
 463         if (!s35390a) {
 464                 err = -ENOMEM;
 465                 goto exit;
 466         }
 467
 468         s35390a->client[0] = client;
 469         i2c_set_clientdata(client, s35390a);
 470
 471         /* This chip uses multiple addresses, use dummy devices for them */
 472         for (i = 1; i < 8; ++i) {
 473                 s35390a->client[i] = i2c_new_dummy(client->adapter,
 474                                         client->addr + i);
 475                 if (!s35390a->client[i]) {
 476                         dev_err(&client->dev, "Address %02x unavailable\n",
 477                                                 client->addr + i);
 478                         err = -EBUSY;
 479                         goto exit_dummy;
 480                 }
 481         }
 482
 483         err_read = s35390a_read_status(s35390a, &status1);
 484         if (err_read < 0) {
 485                 err = err_read;
 486                 dev_err(&client->dev, "error resetting chip\n");
 487                 goto exit_dummy;
 488         }
 489
 490         if (status1 & S35390A_FLAG_24H)
 491                 s35390a->twentyfourhour = 1;
 492         else
 493                 s35390a->twentyfourhour = 0;
 494
 495         if (status1 & S35390A_FLAG_INT2) {
 496                 /* disable alarm (and maybe test mode) */
 497                 buf = 0;
 498                 err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &buf, 1);
 499                 if (err < 0) {
 500                         dev_err(&client->dev, "error disabling alarm");
 501                         goto exit_dummy;
 502                 }
 503         } else {
 504                 err = s35390a_disable_test_mode(s35390a);
 505                 if (err < 0) {
 506                         dev_err(&client->dev, "error disabling test mode\n");
 507                         goto exit_dummy;
 508                 }
 509         }
 510
 511         if (err_read > 0 || s35390a_get_datetime(client, &tm) < 0)
 512                 dev_warn(&client->dev, "clock needs to be set\n");
 513
 514         device_set_wakeup_capable(&client->dev, 1);
 515
 516         s35390a->rtc = devm_rtc_device_register(&client->dev,
 517                                         s35390a_driver.driver.name,
 518                                         &s35390a_rtc_ops, THIS_MODULE);
 519
 520         if (IS_ERR(s35390a->rtc)) {
 521                 err = PTR_ERR(s35390a->rtc);
 522                 goto exit_dummy;
 523         }
 524
 525         if (status1 & S35390A_FLAG_INT2)
 526                 rtc_update_irq(s35390a->rtc, 1, RTC_AF);
 527
 528         return 0;
 529
 530 exit_dummy:
 531         for (i = 1; i < 8; ++i)
 532                 if (s35390a->client[i])
 533                         i2c_unregister_device(s35390a->client[i]);
 534
 535 exit:
 536         return err;
 537 }
 538
 539 static int s35390a_remove(struct i2c_client *client)
 540 {
 541         unsigned int i;
 542         struct s35390a *s35390a = i2c_get_clientdata(client);
 543
 544         for (i = 1; i < 8; ++i)
 545                 if (s35390a->client[i])
 546                         i2c_unregister_device(s35390a->client[i]);
 547
 548         return 0;
 549 }
 550
 551 static struct i2c_driver s35390a_driver = {
 552         .driver         = {
 553                 .name   = "rtc-s35390a",
 554                 .of_match_table = of_match_ptr(s35390a_of_match),
 555         },
 556         .probe          = s35390a_probe,
 557         .remove         = s35390a_remove,
 558         .id_table       = s35390a_id,
 559 };
 560
 561 module_i2c_driver(s35390a_driver);
 562
 563 MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>");
 564 MODULE_DESCRIPTION("S35390A RTC driver");
 565 MODULE_LICENSE("GPL");