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 /*
 110  * Returns <0 on error, 0 if rtc is setup fine and 1 if the chip was reset.
 111  * To keep the information if an irq is pending, pass the value read from
 112  * STATUS1 to the caller.
 113  */
 114 static int s35390a_reset(struct s35390a *s35390a, char *status1)
 115 {
 116         char buf;
 117         int ret;
 118         unsigned initcount = 0;
 119
 120         ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, status1, 1);
 121         if (ret < 0)
 122                 return ret;
 123
 124         if (*status1 & S35390A_FLAG_POC)
 125                 /*
 126                  * Do not communicate for 0.5 seconds since the power-on
 127                  * detection circuit is in operation.
 128                  */
 129                 msleep(500);
 130         else if (!(*status1 & S35390A_FLAG_BLD))
 131                 /*
 132                  * If both POC and BLD are unset everything is fine.
 133                  */
 134                 return 0;
 135
 136         /*
 137          * At least one of POC and BLD are set, so reinitialise chip. Keeping
 138          * this information in the hardware to know later that the time isn't
 139          * valid is unfortunately not possible because POC and BLD are cleared
 140          * on read. So the reset is best done now.
 141          *
 142          * The 24H bit is kept over reset, so set it already here.
 143          */
 144 initialize:
 145         *status1 = S35390A_FLAG_24H;
 146         buf = S35390A_FLAG_RESET | S35390A_FLAG_24H;
 147         ret = s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
 148
 149         if (ret < 0)
 150                 return ret;
 151
 152         ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
 153         if (ret < 0)
 154                 return ret;
 155
 156         if (buf & (S35390A_FLAG_POC | S35390A_FLAG_BLD)) {
 157                 /* Try up to five times to reset the chip */
 158                 if (initcount < 5) {
 159                         ++initcount;
 160                         goto initialize;
 161                 } else
 162                         return -EIO;
 163         }
 164
 165         return 1;
 166 }
 167
 168 static int s35390a_disable_test_mode(struct s35390a *s35390a)
 169 {
 170         char buf[1];
 171
 172         if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0)
 173                 return -EIO;
 174
 175         if (!(buf[0] & S35390A_FLAG_TEST))
 176                 return 0;
 177
 178         buf[0] &= ~S35390A_FLAG_TEST;
 179         return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf));
 180 }
 181
 182 static char s35390a_hr2reg(struct s35390a *s35390a, int hour)
 183 {
 184         if (s35390a->twentyfourhour)
 185                 return bin2bcd(hour);
 186
 187         if (hour < 12)
 188                 return bin2bcd(hour);
 189
 190         return 0x40 | bin2bcd(hour - 12);
 191 }
 192
 193 static int s35390a_reg2hr(struct s35390a *s35390a, char reg)
 194 {
 195         unsigned hour;
 196
 197         if (s35390a->twentyfourhour)
 198                 return bcd2bin(reg & 0x3f);
 199
 200         hour = bcd2bin(reg & 0x3f);
 201         if (reg & 0x40)
 202                 hour += 12;
 203
 204         return hour;
 205 }
 206
 207 static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm)
 208 {
 209         struct s35390a  *s35390a = i2c_get_clientdata(client);
 210         int i, err;
 211         char buf[7];
 212
 213         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, "
 214                 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
 215                 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
 216                 tm->tm_wday);
 217
 218         buf[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 100);
 219         buf[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon + 1);
 220         buf[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday);
 221         buf[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday);
 222         buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour);
 223         buf[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min);
 224         buf[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec);
 225
 226         /* This chip expects the bits of each byte to be in reverse order */
 227         for (i = 0; i < 7; ++i)
 228                 buf[i] = bitrev8(buf[i]);
 229
 230         err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
 231
 232         return err;
 233 }
 234
 235 static int s35390a_get_datetime(struct i2c_client *client, struct rtc_time *tm)
 236 {
 237         struct s35390a *s35390a = i2c_get_clientdata(client);
 238         char buf[7];
 239         int i, err;
 240
 241         err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
 242         if (err < 0)
 243                 return err;
 244
 245         /* This chip returns the bits of each byte in reverse order */
 246         for (i = 0; i < 7; ++i)
 247                 buf[i] = bitrev8(buf[i]);
 248
 249         tm->tm_sec = bcd2bin(buf[S35390A_BYTE_SECS]);
 250         tm->tm_min = bcd2bin(buf[S35390A_BYTE_MINS]);
 251         tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]);
 252         tm->tm_wday = bcd2bin(buf[S35390A_BYTE_WDAY]);
 253         tm->tm_mday = bcd2bin(buf[S35390A_BYTE_DAY]);
 254         tm->tm_mon = bcd2bin(buf[S35390A_BYTE_MONTH]) - 1;
 255         tm->tm_year = bcd2bin(buf[S35390A_BYTE_YEAR]) + 100;
 256
 257         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, "
 258                 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
 259                 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
 260                 tm->tm_wday);
 261
 262         return rtc_valid_tm(tm);
 263 }
 264
 265 static int s35390a_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
 266 {
 267         struct s35390a *s35390a = i2c_get_clientdata(client);
 268         char buf[3], sts = 0;
 269         int err, i;
 270
 271         dev_dbg(&client->dev, "%s: alm is secs=%d, mins=%d, hours=%d mday=%d, "\
 272                 "mon=%d, year=%d, wday=%d\n", __func__, alm->time.tm_sec,
 273                 alm->time.tm_min, alm->time.tm_hour, alm->time.tm_mday,
 274                 alm->time.tm_mon, alm->time.tm_year, alm->time.tm_wday);
 275
 276         /* disable interrupt (which deasserts the irq line) */
 277         err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
 278         if (err < 0)
 279                 return err;
 280
 281         /* clear pending interrupt (in STATUS1 only), if any */
 282         err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &sts, sizeof(sts));
 283         if (err < 0)
 284                 return err;
 285
 286         if (alm->enabled)
 287                 sts = S35390A_INT2_MODE_ALARM;
 288         else
 289                 sts = S35390A_INT2_MODE_NOINTR;
 290
 291         /* This chip expects the bits of each byte to be in reverse order */
 292         sts = bitrev8(sts);
 293
 294         /* set interupt mode*/
 295         err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
 296         if (err < 0)
 297                 return err;
 298
 299         if (alm->time.tm_wday != -1)
 300                 buf[S35390A_ALRM_BYTE_WDAY] = bin2bcd(alm->time.tm_wday) | 0x80;
 301         else
 302                 buf[S35390A_ALRM_BYTE_WDAY] = 0;
 303
 304         buf[S35390A_ALRM_BYTE_HOURS] = s35390a_hr2reg(s35390a,
 305                         alm->time.tm_hour) | 0x80;
 306         buf[S35390A_ALRM_BYTE_MINS] = bin2bcd(alm->time.tm_min) | 0x80;
 307
 308         if (alm->time.tm_hour >= 12)
 309                 buf[S35390A_ALRM_BYTE_HOURS] |= 0x40;
 310
 311         for (i = 0; i < 3; ++i)
 312                 buf[i] = bitrev8(buf[i]);
 313
 314         err = s35390a_set_reg(s35390a, S35390A_CMD_INT2_REG1, buf,
 315                                                                 sizeof(buf));
 316
 317         return err;
 318 }
 319
 320 static int s35390a_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
 321 {
 322         struct s35390a *s35390a = i2c_get_clientdata(client);
 323         char buf[3], sts;
 324         int i, err;
 325
 326         err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
 327         if (err < 0)
 328                 return err;
 329
 330         if ((bitrev8(sts) & S35390A_INT2_MODE_MASK) != S35390A_INT2_MODE_ALARM) {
 331                 /*
 332                  * When the alarm isn't enabled, the register to configure
 333                  * the alarm time isn't accessible.
 334                  */
 335                 alm->enabled = 0;
 336                 return 0;
 337         } else {
 338                 alm->enabled = 1;
 339         }
 340
 341         err = s35390a_get_reg(s35390a, S35390A_CMD_INT2_REG1, buf, sizeof(buf));
 342         if (err < 0)
 343                 return err;
 344
 345         /* This chip returns the bits of each byte in reverse order */
 346         for (i = 0; i < 3; ++i)
 347                 buf[i] = bitrev8(buf[i]);
 348
 349         /*
 350          * B0 of the three matching registers is an enable flag. Iff it is set
 351          * the configured value is used for matching.
 352          */
 353         if (buf[S35390A_ALRM_BYTE_WDAY] & 0x80)
 354                 alm->time.tm_wday =
 355                         bcd2bin(buf[S35390A_ALRM_BYTE_WDAY] & ~0x80);
 356
 357         if (buf[S35390A_ALRM_BYTE_HOURS] & 0x80)
 358                 alm->time.tm_hour =
 359                         s35390a_reg2hr(s35390a,
 360                                        buf[S35390A_ALRM_BYTE_HOURS] & ~0x80);
 361
 362         if (buf[S35390A_ALRM_BYTE_MINS] & 0x80)
 363                 alm->time.tm_min = bcd2bin(buf[S35390A_ALRM_BYTE_MINS] & ~0x80);
 364
 365         /* alarm triggers always at s=0 */
 366         alm->time.tm_sec = 0;
 367
 368         dev_dbg(&client->dev, "%s: alm is mins=%d, hours=%d, wday=%d\n",
 369                         __func__, alm->time.tm_min, alm->time.tm_hour,
 370                         alm->time.tm_wday);
 371
 372         return 0;
 373 }
 374
 375 static int s35390a_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 376 {
 377         return s35390a_read_alarm(to_i2c_client(dev), alm);
 378 }
 379
 380 static int s35390a_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 381 {
 382         return s35390a_set_alarm(to_i2c_client(dev), alm);
 383 }
 384
 385 static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm)
 386 {
 387         return s35390a_get_datetime(to_i2c_client(dev), tm);
 388 }
 389
 390 static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)
 391 {
 392         return s35390a_set_datetime(to_i2c_client(dev), tm);
 393 }
 394
 395 static const struct rtc_class_ops s35390a_rtc_ops = {
 396         .read_time      = s35390a_rtc_read_time,
 397         .set_time       = s35390a_rtc_set_time,
 398         .set_alarm      = s35390a_rtc_set_alarm,
 399         .read_alarm     = s35390a_rtc_read_alarm,
 400
 401 };
 402
 403 static struct i2c_driver s35390a_driver;
 404
 405 static int s35390a_probe(struct i2c_client *client,
 406                          const struct i2c_device_id *id)
 407 {
 408         int err, err_reset;
 409         unsigned int i;
 410         struct s35390a *s35390a;
 411         struct rtc_time tm;
 412         char buf, status1;
 413
 414         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 415                 err = -ENODEV;
 416                 goto exit;
 417         }
 418
 419         s35390a = devm_kzalloc(&client->dev, sizeof(struct s35390a),
 420                                 GFP_KERNEL);
 421         if (!s35390a) {
 422                 err = -ENOMEM;
 423                 goto exit;
 424         }
 425
 426         s35390a->client[0] = client;
 427         i2c_set_clientdata(client, s35390a);
 428
 429         /* This chip uses multiple addresses, use dummy devices for them */
 430         for (i = 1; i < 8; ++i) {
 431                 s35390a->client[i] = i2c_new_dummy(client->adapter,
 432                                         client->addr + i);
 433                 if (!s35390a->client[i]) {
 434                         dev_err(&client->dev, "Address %02x unavailable\n",
 435                                                 client->addr + i);
 436                         err = -EBUSY;
 437                         goto exit_dummy;
 438                 }
 439         }
 440
 441         err_reset = s35390a_reset(s35390a, &status1);
 442         if (err_reset < 0) {
 443                 err = err_reset;
 444                 dev_err(&client->dev, "error resetting chip\n");
 445                 goto exit_dummy;
 446         }
 447
 448         if (status1 & S35390A_FLAG_24H)
 449                 s35390a->twentyfourhour = 1;
 450         else
 451                 s35390a->twentyfourhour = 0;
 452
 453         if (status1 & S35390A_FLAG_INT2) {
 454                 /* disable alarm (and maybe test mode) */
 455                 buf = 0;
 456                 err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &buf, 1);
 457                 if (err < 0) {
 458                         dev_err(&client->dev, "error disabling alarm");
 459                         goto exit_dummy;
 460                 }
 461         } else {
 462                 err = s35390a_disable_test_mode(s35390a);
 463                 if (err < 0) {
 464                         dev_err(&client->dev, "error disabling test mode\n");
 465                         goto exit_dummy;
 466                 }
 467         }
 468
 469         if (err_reset > 0 || s35390a_get_datetime(client, &tm) < 0)
 470                 dev_warn(&client->dev, "clock needs to be set\n");
 471
 472         device_set_wakeup_capable(&client->dev, 1);
 473
 474         s35390a->rtc = devm_rtc_device_register(&client->dev,
 475                                         s35390a_driver.driver.name,
 476                                         &s35390a_rtc_ops, THIS_MODULE);
 477
 478         if (IS_ERR(s35390a->rtc)) {
 479                 err = PTR_ERR(s35390a->rtc);
 480                 goto exit_dummy;
 481         }
 482
 483         if (status1 & S35390A_FLAG_INT2)
 484                 rtc_update_irq(s35390a->rtc, 1, RTC_AF);
 485
 486         return 0;
 487
 488 exit_dummy:
 489         for (i = 1; i < 8; ++i)
 490                 if (s35390a->client[i])
 491                         i2c_unregister_device(s35390a->client[i]);
 492
 493 exit:
 494         return err;
 495 }
 496
 497 static int s35390a_remove(struct i2c_client *client)
 498 {
 499         unsigned int i;
 500         struct s35390a *s35390a = i2c_get_clientdata(client);
 501
 502         for (i = 1; i < 8; ++i)
 503                 if (s35390a->client[i])
 504                         i2c_unregister_device(s35390a->client[i]);
 505
 506         return 0;
 507 }
 508
 509 static struct i2c_driver s35390a_driver = {
 510         .driver         = {
 511                 .name   = "rtc-s35390a",
 512                 .of_match_table = of_match_ptr(s35390a_of_match),
 513         },
 514         .probe          = s35390a_probe,
 515         .remove         = s35390a_remove,
 516         .id_table       = s35390a_id,
 517 };
 518
 519 module_i2c_driver(s35390a_driver);
 520
 521 MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>");
 522 MODULE_DESCRIPTION("S35390A RTC driver");
 523 MODULE_LICENSE("GPL");