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_rtc_set_time(struct device *dev, struct rtc_time *tm)
 214 {
 215         struct i2c_client *client = to_i2c_client(dev);
 216         struct s35390a  *s35390a = i2c_get_clientdata(client);
 217         int i, err;
 218         char buf[7], status;
 219
 220         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, "
 221                 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
 222                 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
 223                 tm->tm_wday);
 224
 225         if (s35390a_read_status(s35390a, &status) == 1)
 226                 s35390a_init(s35390a);
 227
 228         buf[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 100);
 229         buf[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon + 1);
 230         buf[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday);
 231         buf[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday);
 232         buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour);
 233         buf[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min);
 234         buf[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec);
 235
 236         /* This chip expects the bits of each byte to be in reverse order */
 237         for (i = 0; i < 7; ++i)
 238                 buf[i] = bitrev8(buf[i]);
 239
 240         err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
 241
 242         return err;
 243 }
 244
 245 static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm)
 246 {
 247         struct i2c_client *client = to_i2c_client(dev);
 248         struct s35390a *s35390a = i2c_get_clientdata(client);
 249         char buf[7], status;
 250         int i, err;
 251
 252         if (s35390a_read_status(s35390a, &status) == 1)
 253                 return -EINVAL;
 254
 255         err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
 256         if (err < 0)
 257                 return err;
 258
 259         /* This chip returns the bits of each byte in reverse order */
 260         for (i = 0; i < 7; ++i)
 261                 buf[i] = bitrev8(buf[i]);
 262
 263         tm->tm_sec = bcd2bin(buf[S35390A_BYTE_SECS]);
 264         tm->tm_min = bcd2bin(buf[S35390A_BYTE_MINS]);
 265         tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]);
 266         tm->tm_wday = bcd2bin(buf[S35390A_BYTE_WDAY]);
 267         tm->tm_mday = bcd2bin(buf[S35390A_BYTE_DAY]);
 268         tm->tm_mon = bcd2bin(buf[S35390A_BYTE_MONTH]) - 1;
 269         tm->tm_year = bcd2bin(buf[S35390A_BYTE_YEAR]) + 100;
 270
 271         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, "
 272                 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
 273                 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
 274                 tm->tm_wday);
 275
 276         return 0;
 277 }
 278
 279 static int s35390a_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 280 {
 281         struct i2c_client *client = to_i2c_client(dev);
 282         struct s35390a *s35390a = i2c_get_clientdata(client);
 283         char buf[3], sts = 0;
 284         int err, i;
 285
 286         dev_dbg(&client->dev, "%s: alm is secs=%d, mins=%d, hours=%d mday=%d, "\
 287                 "mon=%d, year=%d, wday=%d\n", __func__, alm->time.tm_sec,
 288                 alm->time.tm_min, alm->time.tm_hour, alm->time.tm_mday,
 289                 alm->time.tm_mon, alm->time.tm_year, alm->time.tm_wday);
 290
 291         /* disable interrupt (which deasserts the irq line) */
 292         err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
 293         if (err < 0)
 294                 return err;
 295
 296         /* clear pending interrupt (in STATUS1 only), if any */
 297         err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &sts, sizeof(sts));
 298         if (err < 0)
 299                 return err;
 300
 301         if (alm->enabled)
 302                 sts = S35390A_INT2_MODE_ALARM;
 303         else
 304                 sts = S35390A_INT2_MODE_NOINTR;
 305
 306         /* This chip expects the bits of each byte to be in reverse order */
 307         sts = bitrev8(sts);
 308
 309         /* set interupt mode*/
 310         err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
 311         if (err < 0)
 312                 return err;
 313
 314         if (alm->time.tm_wday != -1)
 315                 buf[S35390A_ALRM_BYTE_WDAY] = bin2bcd(alm->time.tm_wday) | 0x80;
 316         else
 317                 buf[S35390A_ALRM_BYTE_WDAY] = 0;
 318
 319         buf[S35390A_ALRM_BYTE_HOURS] = s35390a_hr2reg(s35390a,
 320                         alm->time.tm_hour) | 0x80;
 321         buf[S35390A_ALRM_BYTE_MINS] = bin2bcd(alm->time.tm_min) | 0x80;
 322
 323         if (alm->time.tm_hour >= 12)
 324                 buf[S35390A_ALRM_BYTE_HOURS] |= 0x40;
 325
 326         for (i = 0; i < 3; ++i)
 327                 buf[i] = bitrev8(buf[i]);
 328
 329         err = s35390a_set_reg(s35390a, S35390A_CMD_INT2_REG1, buf,
 330                                                                 sizeof(buf));
 331
 332         return err;
 333 }
 334
 335 static int s35390a_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 336 {
 337         struct i2c_client *client = to_i2c_client(dev);
 338         struct s35390a *s35390a = i2c_get_clientdata(client);
 339         char buf[3], sts;
 340         int i, err;
 341
 342         err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
 343         if (err < 0)
 344                 return err;
 345
 346         if ((bitrev8(sts) & S35390A_INT2_MODE_MASK) != S35390A_INT2_MODE_ALARM) {
 347                 /*
 348                  * When the alarm isn't enabled, the register to configure
 349                  * the alarm time isn't accessible.
 350                  */
 351                 alm->enabled = 0;
 352                 return 0;
 353         } else {
 354                 alm->enabled = 1;
 355         }
 356
 357         err = s35390a_get_reg(s35390a, S35390A_CMD_INT2_REG1, buf, sizeof(buf));
 358         if (err < 0)
 359                 return err;
 360
 361         /* This chip returns the bits of each byte in reverse order */
 362         for (i = 0; i < 3; ++i)
 363                 buf[i] = bitrev8(buf[i]);
 364
 365         /*
 366          * B0 of the three matching registers is an enable flag. Iff it is set
 367          * the configured value is used for matching.
 368          */
 369         if (buf[S35390A_ALRM_BYTE_WDAY] & 0x80)
 370                 alm->time.tm_wday =
 371                         bcd2bin(buf[S35390A_ALRM_BYTE_WDAY] & ~0x80);
 372
 373         if (buf[S35390A_ALRM_BYTE_HOURS] & 0x80)
 374                 alm->time.tm_hour =
 375                         s35390a_reg2hr(s35390a,
 376                                        buf[S35390A_ALRM_BYTE_HOURS] & ~0x80);
 377
 378         if (buf[S35390A_ALRM_BYTE_MINS] & 0x80)
 379                 alm->time.tm_min = bcd2bin(buf[S35390A_ALRM_BYTE_MINS] & ~0x80);
 380
 381         /* alarm triggers always at s=0 */
 382         alm->time.tm_sec = 0;
 383
 384         dev_dbg(&client->dev, "%s: alm is mins=%d, hours=%d, wday=%d\n",
 385                         __func__, alm->time.tm_min, alm->time.tm_hour,
 386                         alm->time.tm_wday);
 387
 388         return 0;
 389 }
 390
 391 static int s35390a_rtc_ioctl(struct device *dev, unsigned int cmd,
 392                              unsigned long arg)
 393 {
 394         struct i2c_client *client = to_i2c_client(dev);
 395         struct s35390a *s35390a = i2c_get_clientdata(client);
 396         char sts;
 397         int err;
 398
 399         switch (cmd) {
 400         case RTC_VL_READ:
 401                 /* s35390a_reset set lowvoltage flag and init RTC if needed */
 402                 err = s35390a_read_status(s35390a, &sts);
 403                 if (err < 0)
 404                         return err;
 405                 if (copy_to_user((void __user *)arg, &err, sizeof(int)))
 406                         return -EFAULT;
 407                 break;
 408         case RTC_VL_CLR:
 409                 /* update flag and clear register */
 410                 err = s35390a_init(s35390a);
 411                 if (err < 0)
 412                         return err;
 413                 break;
 414         default:
 415                 return -ENOIOCTLCMD;
 416         }
 417
 418         return 0;
 419 }
 420
 421 static const struct rtc_class_ops s35390a_rtc_ops = {
 422         .read_time      = s35390a_rtc_read_time,
 423         .set_time       = s35390a_rtc_set_time,
 424         .set_alarm      = s35390a_rtc_set_alarm,
 425         .read_alarm     = s35390a_rtc_read_alarm,
 426         .ioctl          = s35390a_rtc_ioctl,
 427 };
 428
 429 static struct i2c_driver s35390a_driver;
 430
 431 static int s35390a_probe(struct i2c_client *client,
 432                          const struct i2c_device_id *id)
 433 {
 434         int err, err_read;
 435         unsigned int i;
 436         struct s35390a *s35390a;
 437         char buf, status1;
 438
 439         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 440                 err = -ENODEV;
 441                 goto exit;
 442         }
 443
 444         s35390a = devm_kzalloc(&client->dev, sizeof(struct s35390a),
 445                                 GFP_KERNEL);
 446         if (!s35390a) {
 447                 err = -ENOMEM;
 448                 goto exit;
 449         }
 450
 451         s35390a->client[0] = client;
 452         i2c_set_clientdata(client, s35390a);
 453
 454         /* This chip uses multiple addresses, use dummy devices for them */
 455         for (i = 1; i < 8; ++i) {
 456                 s35390a->client[i] = i2c_new_dummy(client->adapter,
 457                                         client->addr + i);
 458                 if (!s35390a->client[i]) {
 459                         dev_err(&client->dev, "Address %02x unavailable\n",
 460                                                 client->addr + i);
 461                         err = -EBUSY;
 462                         goto exit_dummy;
 463                 }
 464         }
 465
 466         err_read = s35390a_read_status(s35390a, &status1);
 467         if (err_read < 0) {
 468                 err = err_read;
 469                 dev_err(&client->dev, "error resetting chip\n");
 470                 goto exit_dummy;
 471         }
 472
 473         if (status1 & S35390A_FLAG_24H)
 474                 s35390a->twentyfourhour = 1;
 475         else
 476                 s35390a->twentyfourhour = 0;
 477
 478         if (status1 & S35390A_FLAG_INT2) {
 479                 /* disable alarm (and maybe test mode) */
 480                 buf = 0;
 481                 err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &buf, 1);
 482                 if (err < 0) {
 483                         dev_err(&client->dev, "error disabling alarm");
 484                         goto exit_dummy;
 485                 }
 486         } else {
 487                 err = s35390a_disable_test_mode(s35390a);
 488                 if (err < 0) {
 489                         dev_err(&client->dev, "error disabling test mode\n");
 490                         goto exit_dummy;
 491                 }
 492         }
 493
 494         device_set_wakeup_capable(&client->dev, 1);
 495
 496         s35390a->rtc = devm_rtc_device_register(&client->dev,
 497                                         s35390a_driver.driver.name,
 498                                         &s35390a_rtc_ops, THIS_MODULE);
 499
 500         if (IS_ERR(s35390a->rtc)) {
 501                 err = PTR_ERR(s35390a->rtc);
 502                 goto exit_dummy;
 503         }
 504
 505         if (status1 & S35390A_FLAG_INT2)
 506                 rtc_update_irq(s35390a->rtc, 1, RTC_AF);
 507
 508         return 0;
 509
 510 exit_dummy:
 511         for (i = 1; i < 8; ++i)
 512                 if (s35390a->client[i])
 513                         i2c_unregister_device(s35390a->client[i]);
 514
 515 exit:
 516         return err;
 517 }
 518
 519 static int s35390a_remove(struct i2c_client *client)
 520 {
 521         unsigned int i;
 522         struct s35390a *s35390a = i2c_get_clientdata(client);
 523
 524         for (i = 1; i < 8; ++i)
 525                 if (s35390a->client[i])
 526                         i2c_unregister_device(s35390a->client[i]);
 527
 528         return 0;
 529 }
 530
 531 static struct i2c_driver s35390a_driver = {
 532         .driver         = {
 533                 .name   = "rtc-s35390a",
 534                 .of_match_table = of_match_ptr(s35390a_of_match),
 535         },
 536         .probe          = s35390a_probe,
 537         .remove         = s35390a_remove,
 538         .id_table       = s35390a_id,
 539 };
 540
 541 module_i2c_driver(s35390a_driver);
 542
 543 MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>");
 544 MODULE_DESCRIPTION("S35390A RTC driver");
 545 MODULE_LICENSE("GPL");