drivers/rtc/rtc-x1205.c

   1 /*
   2  * An i2c driver for the Xicor/Intersil X1205 RTC
   3  * Copyright 2004 Karen Spearel
   4  * Copyright 2005 Alessandro Zummo
   5  *
   6  * please send all reports to:
   7  *      Karen Spearel <kas111 at gmail dot com>
   8  *      Alessandro Zummo <a.zummo@towertech.it>
   9  *
  10  * based on a lot of other RTC drivers.
  11  *
  12  * Information and datasheet:
  13  * http://www.intersil.com/cda/deviceinfo/0,1477,X1205,00.html
  14  *
  15  * This program is free software; you can redistribute it and/or modify
  16  * it under the terms of the GNU General Public License version 2 as
  17  * published by the Free Software Foundation.
  18  */
  19
  20 #include <linux/i2c.h>
  21 #include <linux/bcd.h>
  22 #include <linux/rtc.h>
  23 #include <linux/delay.h>
  24
  25 #define DRV_VERSION "1.0.8"
  26
  27 /* offsets into CCR area */
  28
  29 #define CCR_SEC                 0
  30 #define CCR_MIN                 1
  31 #define CCR_HOUR                2
  32 #define CCR_MDAY                3
  33 #define CCR_MONTH               4
  34 #define CCR_YEAR                5
  35 #define CCR_WDAY                6
  36 #define CCR_Y2K                 7
  37
  38 #define X1205_REG_SR            0x3F    /* status register */
  39 #define X1205_REG_Y2K           0x37
  40 #define X1205_REG_DW            0x36
  41 #define X1205_REG_YR            0x35
  42 #define X1205_REG_MO            0x34
  43 #define X1205_REG_DT            0x33
  44 #define X1205_REG_HR            0x32
  45 #define X1205_REG_MN            0x31
  46 #define X1205_REG_SC            0x30
  47 #define X1205_REG_DTR           0x13
  48 #define X1205_REG_ATR           0x12
  49 #define X1205_REG_INT           0x11
  50 #define X1205_REG_0             0x10
  51 #define X1205_REG_Y2K1          0x0F
  52 #define X1205_REG_DWA1          0x0E
  53 #define X1205_REG_YRA1          0x0D
  54 #define X1205_REG_MOA1          0x0C
  55 #define X1205_REG_DTA1          0x0B
  56 #define X1205_REG_HRA1          0x0A
  57 #define X1205_REG_MNA1          0x09
  58 #define X1205_REG_SCA1          0x08
  59 #define X1205_REG_Y2K0          0x07
  60 #define X1205_REG_DWA0          0x06
  61 #define X1205_REG_YRA0          0x05
  62 #define X1205_REG_MOA0          0x04
  63 #define X1205_REG_DTA0          0x03
  64 #define X1205_REG_HRA0          0x02
  65 #define X1205_REG_MNA0          0x01
  66 #define X1205_REG_SCA0          0x00
  67
  68 #define X1205_CCR_BASE          0x30    /* Base address of CCR */
  69 #define X1205_ALM0_BASE         0x00    /* Base address of ALARM0 */
  70
  71 #define X1205_SR_RTCF           0x01    /* Clock failure */
  72 #define X1205_SR_WEL            0x02    /* Write Enable Latch */
  73 #define X1205_SR_RWEL           0x04    /* Register Write Enable */
  74
  75 #define X1205_DTR_DTR0          0x01
  76 #define X1205_DTR_DTR1          0x02
  77 #define X1205_DTR_DTR2          0x04
  78
  79 #define X1205_HR_MIL            0x80    /* Set in ccr.hour for 24 hr mode */
  80
  81 static struct i2c_driver x1205_driver;
  82
  83 /*
  84  * In the routines that deal directly with the x1205 hardware, we use
  85  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
  86  * Epoch is initialized as 2000. Time is set to UTC.
  87  */
  88 static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,
  89                                 unsigned char reg_base)
  90 {
  91         unsigned char dt_addr[2] = { 0, reg_base };
  92
  93         unsigned char buf[8];
  94
  95         struct i2c_msg msgs[] = {
  96                 { client->addr, 0, 2, dt_addr },        /* setup read ptr */
  97                 { client->addr, I2C_M_RD, 8, buf },     /* read date */
  98         };
  99
 100         /* read date registers */
 101         if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
 102                 dev_err(&client->dev, "%s: read error\n", __func__);
 103                 return -EIO;
 104         }
 105
 106         dev_dbg(&client->dev,
 107                 "%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
 108                 "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
 109                 __func__,
 110                 buf[0], buf[1], buf[2], buf[3],
 111                 buf[4], buf[5], buf[6], buf[7]);
 112
 113         tm->tm_sec = BCD2BIN(buf[CCR_SEC]);
 114         tm->tm_min = BCD2BIN(buf[CCR_MIN]);
 115         tm->tm_hour = BCD2BIN(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */
 116         tm->tm_mday = BCD2BIN(buf[CCR_MDAY]);
 117         tm->tm_mon = BCD2BIN(buf[CCR_MONTH]) - 1; /* mon is 0-11 */
 118         tm->tm_year = BCD2BIN(buf[CCR_YEAR])
 119                         + (BCD2BIN(buf[CCR_Y2K]) * 100) - 1900;
 120         tm->tm_wday = buf[CCR_WDAY];
 121
 122         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
 123                 "mday=%d, mon=%d, year=%d, wday=%d\n",
 124                 __func__,
 125                 tm->tm_sec, tm->tm_min, tm->tm_hour,
 126                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 127
 128         return 0;
 129 }
 130
 131 static int x1205_get_status(struct i2c_client *client, unsigned char *sr)
 132 {
 133         static unsigned char sr_addr[2] = { 0, X1205_REG_SR };
 134
 135         struct i2c_msg msgs[] = {
 136                 { client->addr, 0, 2, sr_addr },        /* setup read ptr */
 137                 { client->addr, I2C_M_RD, 1, sr },      /* read status */
 138         };
 139
 140         /* read status register */
 141         if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
 142                 dev_err(&client->dev, "%s: read error\n", __func__);
 143                 return -EIO;
 144         }
 145
 146         return 0;
 147 }
 148
 149 static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
 150                                 int datetoo, u8 reg_base)
 151 {
 152         int i, xfer;
 153         unsigned char buf[8];
 154
 155         static const unsigned char wel[3] = { 0, X1205_REG_SR,
 156                                                 X1205_SR_WEL };
 157
 158         static const unsigned char rwel[3] = { 0, X1205_REG_SR,
 159                                                 X1205_SR_WEL | X1205_SR_RWEL };
 160
 161         static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 };
 162
 163         dev_dbg(&client->dev,
 164                 "%s: secs=%d, mins=%d, hours=%d\n",
 165                 __func__,
 166                 tm->tm_sec, tm->tm_min, tm->tm_hour);
 167
 168         buf[CCR_SEC] = BIN2BCD(tm->tm_sec);
 169         buf[CCR_MIN] = BIN2BCD(tm->tm_min);
 170
 171         /* set hour and 24hr bit */
 172         buf[CCR_HOUR] = BIN2BCD(tm->tm_hour) | X1205_HR_MIL;
 173
 174         /* should we also set the date? */
 175         if (datetoo) {
 176                 dev_dbg(&client->dev,
 177                         "%s: mday=%d, mon=%d, year=%d, wday=%d\n",
 178                         __func__,
 179                         tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
 180
 181                 buf[CCR_MDAY] = BIN2BCD(tm->tm_mday);
 182
 183                 /* month, 1 - 12 */
 184                 buf[CCR_MONTH] = BIN2BCD(tm->tm_mon + 1);
 185
 186                 /* year, since the rtc epoch*/
 187                 buf[CCR_YEAR] = BIN2BCD(tm->tm_year % 100);
 188                 buf[CCR_WDAY] = tm->tm_wday & 0x07;
 189                 buf[CCR_Y2K] = BIN2BCD(tm->tm_year / 100);
 190         }
 191
 192         /* this sequence is required to unlock the chip */
 193         if ((xfer = i2c_master_send(client, wel, 3)) != 3) {
 194                 dev_err(&client->dev, "%s: wel - %d\n", __func__, xfer);
 195                 return -EIO;
 196         }
 197
 198         if ((xfer = i2c_master_send(client, rwel, 3)) != 3) {
 199                 dev_err(&client->dev, "%s: rwel - %d\n", __func__, xfer);
 200                 return -EIO;
 201         }
 202
 203         /* write register's data */
 204         for (i = 0; i < (datetoo ? 8 : 3); i++) {
 205                 unsigned char rdata[3] = { 0, reg_base + i, buf[i] };
 206
 207                 xfer = i2c_master_send(client, rdata, 3);
 208                 if (xfer != 3) {
 209                         dev_err(&client->dev,
 210                                 "%s: xfer=%d addr=%02x, data=%02x\n",
 211                                 __func__,
 212                                  xfer, rdata[1], rdata[2]);
 213                         return -EIO;
 214                 }
 215         };
 216
 217         /* disable further writes */
 218         if ((xfer = i2c_master_send(client, diswe, 3)) != 3) {
 219                 dev_err(&client->dev, "%s: diswe - %d\n", __func__, xfer);
 220                 return -EIO;
 221         }
 222
 223         return 0;
 224 }
 225
 226 static int x1205_fix_osc(struct i2c_client *client)
 227 {
 228         int err;
 229         struct rtc_time tm;
 230
 231         tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
 232
 233         if ((err = x1205_set_datetime(client, &tm, 0, X1205_CCR_BASE)) < 0)
 234                 dev_err(&client->dev,
 235                         "unable to restart the oscillator\n");
 236
 237         return err;
 238 }
 239
 240 static int x1205_get_dtrim(struct i2c_client *client, int *trim)
 241 {
 242         unsigned char dtr;
 243         static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR };
 244
 245         struct i2c_msg msgs[] = {
 246                 { client->addr, 0, 2, dtr_addr },       /* setup read ptr */
 247                 { client->addr, I2C_M_RD, 1, &dtr },    /* read dtr */
 248         };
 249
 250         /* read dtr register */
 251         if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
 252                 dev_err(&client->dev, "%s: read error\n", __func__);
 253                 return -EIO;
 254         }
 255
 256         dev_dbg(&client->dev, "%s: raw dtr=%x\n", __func__, dtr);
 257
 258         *trim = 0;
 259
 260         if (dtr & X1205_DTR_DTR0)
 261                 *trim += 20;
 262
 263         if (dtr & X1205_DTR_DTR1)
 264                 *trim += 10;
 265
 266         if (dtr & X1205_DTR_DTR2)
 267                 *trim = -*trim;
 268
 269         return 0;
 270 }
 271
 272 static int x1205_get_atrim(struct i2c_client *client, int *trim)
 273 {
 274         s8 atr;
 275         static unsigned char atr_addr[2] = { 0, X1205_REG_ATR };
 276
 277         struct i2c_msg msgs[] = {
 278                 { client->addr, 0, 2, atr_addr },       /* setup read ptr */
 279                 { client->addr, I2C_M_RD, 1, &atr },    /* read atr */
 280         };
 281
 282         /* read atr register */
 283         if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
 284                 dev_err(&client->dev, "%s: read error\n", __func__);
 285                 return -EIO;
 286         }
 287
 288         dev_dbg(&client->dev, "%s: raw atr=%x\n", __func__, atr);
 289
 290         /* atr is a two's complement value on 6 bits,
 291          * perform sign extension. The formula is
 292          * Catr = (atr * 0.25pF) + 11.00pF.
 293          */
 294         if (atr & 0x20)
 295                 atr |= 0xC0;
 296
 297         dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __func__, atr, atr);
 298
 299         *trim = (atr * 250) + 11000;
 300
 301         dev_dbg(&client->dev, "%s: real=%d\n", __func__, *trim);
 302
 303         return 0;
 304 }
 305
 306 struct x1205_limit
 307 {
 308         unsigned char reg, mask, min, max;
 309 };
 310
 311 static int x1205_validate_client(struct i2c_client *client)
 312 {
 313         int i, xfer;
 314
 315         /* Probe array. We will read the register at the specified
 316          * address and check if the given bits are zero.
 317          */
 318         static const unsigned char probe_zero_pattern[] = {
 319                 /* register, mask */
 320                 X1205_REG_SR,   0x18,
 321                 X1205_REG_DTR,  0xF8,
 322                 X1205_REG_ATR,  0xC0,
 323                 X1205_REG_INT,  0x18,
 324                 X1205_REG_0,    0xFF,
 325         };
 326
 327         static const struct x1205_limit probe_limits_pattern[] = {
 328                 /* register, mask, min, max */
 329                 { X1205_REG_Y2K,        0xFF,   19,     20      },
 330                 { X1205_REG_DW,         0xFF,   0,      6       },
 331                 { X1205_REG_YR,         0xFF,   0,      99      },
 332                 { X1205_REG_MO,         0xFF,   0,      12      },
 333                 { X1205_REG_DT,         0xFF,   0,      31      },
 334                 { X1205_REG_HR,         0x7F,   0,      23      },
 335                 { X1205_REG_MN,         0xFF,   0,      59      },
 336                 { X1205_REG_SC,         0xFF,   0,      59      },
 337                 { X1205_REG_Y2K1,       0xFF,   19,     20      },
 338                 { X1205_REG_Y2K0,       0xFF,   19,     20      },
 339         };
 340
 341         /* check that registers have bits a 0 where expected */
 342         for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) {
 343                 unsigned char buf;
 344
 345                 unsigned char addr[2] = { 0, probe_zero_pattern[i] };
 346
 347                 struct i2c_msg msgs[2] = {
 348                         { client->addr, 0, 2, addr },
 349                         { client->addr, I2C_M_RD, 1, &buf },
 350                 };
 351
 352                 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
 353                         dev_err(&client->dev,
 354                                 "%s: could not read register %x\n",
 355                                 __func__, probe_zero_pattern[i]);
 356
 357                         return -EIO;
 358                 }
 359
 360                 if ((buf & probe_zero_pattern[i+1]) != 0) {
 361                         dev_err(&client->dev,
 362                                 "%s: register=%02x, zero pattern=%d, value=%x\n",
 363                                 __func__, probe_zero_pattern[i], i, buf);
 364
 365                         return -ENODEV;
 366                 }
 367         }
 368
 369         /* check limits (only registers with bcd values) */
 370         for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) {
 371                 unsigned char reg, value;
 372
 373                 unsigned char addr[2] = { 0, probe_limits_pattern[i].reg };
 374
 375                 struct i2c_msg msgs[2] = {
 376                         { client->addr, 0, 2, addr },
 377                         { client->addr, I2C_M_RD, 1, &reg },
 378                 };
 379
 380                 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
 381                         dev_err(&client->dev,
 382                                 "%s: could not read register %x\n",
 383                                 __func__, probe_limits_pattern[i].reg);
 384
 385                         return -EIO;
 386                 }
 387
 388                 value = BCD2BIN(reg & probe_limits_pattern[i].mask);
 389
 390                 if (value > probe_limits_pattern[i].max ||
 391                         value < probe_limits_pattern[i].min) {
 392                         dev_dbg(&client->dev,
 393                                 "%s: register=%x, lim pattern=%d, value=%d\n",
 394                                 __func__, probe_limits_pattern[i].reg,
 395                                 i, value);
 396
 397                         return -ENODEV;
 398                 }
 399         }
 400
 401         return 0;
 402 }
 403
 404 static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 405 {
 406         return x1205_get_datetime(to_i2c_client(dev),
 407                 &alrm->time, X1205_ALM0_BASE);
 408 }
 409
 410 static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 411 {
 412         return x1205_set_datetime(to_i2c_client(dev),
 413                 &alrm->time, 1, X1205_ALM0_BASE);
 414 }
 415
 416 static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm)
 417 {
 418         return x1205_get_datetime(to_i2c_client(dev),
 419                 tm, X1205_CCR_BASE);
 420 }
 421
 422 static int x1205_rtc_set_time(struct device *dev, struct rtc_time *tm)
 423 {
 424         return x1205_set_datetime(to_i2c_client(dev),
 425                 tm, 1, X1205_CCR_BASE);
 426 }
 427
 428 static int x1205_rtc_proc(struct device *dev, struct seq_file *seq)
 429 {
 430         int err, dtrim, atrim;
 431
 432         if ((err = x1205_get_dtrim(to_i2c_client(dev), &dtrim)) == 0)
 433                 seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim);
 434
 435         if ((err = x1205_get_atrim(to_i2c_client(dev), &atrim)) == 0)
 436                 seq_printf(seq, "analog_trim\t: %d.%02d pF\n",
 437                         atrim / 1000, atrim % 1000);
 438         return 0;
 439 }
 440
 441 static const struct rtc_class_ops x1205_rtc_ops = {
 442         .proc           = x1205_rtc_proc,
 443         .read_time      = x1205_rtc_read_time,
 444         .set_time       = x1205_rtc_set_time,
 445         .read_alarm     = x1205_rtc_read_alarm,
 446         .set_alarm      = x1205_rtc_set_alarm,
 447 };
 448
 449 static ssize_t x1205_sysfs_show_atrim(struct device *dev,
 450                                 struct device_attribute *attr, char *buf)
 451 {
 452         int err, atrim;
 453
 454         err = x1205_get_atrim(to_i2c_client(dev), &atrim);
 455         if (err)
 456                 return err;
 457
 458         return sprintf(buf, "%d.%02d pF\n", atrim / 1000, atrim % 1000);
 459 }
 460 static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL);
 461
 462 static ssize_t x1205_sysfs_show_dtrim(struct device *dev,
 463                                 struct device_attribute *attr, char *buf)
 464 {
 465         int err, dtrim;
 466
 467         err = x1205_get_dtrim(to_i2c_client(dev), &dtrim);
 468         if (err)
 469                 return err;
 470
 471         return sprintf(buf, "%d ppm\n", dtrim);
 472 }
 473 static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL);
 474
 475 static int x1205_sysfs_register(struct device *dev)
 476 {
 477         int err;
 478
 479         err = device_create_file(dev, &dev_attr_atrim);
 480         if (err)
 481                 return err;
 482
 483         err = device_create_file(dev, &dev_attr_dtrim);
 484         if (err)
 485                 device_remove_file(dev, &dev_attr_atrim);
 486
 487         return err;
 488 }
 489
 490 static void x1205_sysfs_unregister(struct device *dev)
 491 {
 492         device_remove_file(dev, &dev_attr_atrim);
 493         device_remove_file(dev, &dev_attr_dtrim);
 494 }
 495
 496
 497 static int x1205_probe(struct i2c_client *client,
 498                         const struct i2c_device_id *id)
 499 {
 500         int err = 0;
 501         unsigned char sr;
 502         struct rtc_device *rtc;
 503
 504         dev_dbg(&client->dev, "%s\n", __func__);
 505
 506         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 507                 return -ENODEV;
 508
 509         if (x1205_validate_client(client) < 0)
 510                 return -ENODEV;
 511
 512         dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
 513
 514         rtc = rtc_device_register(x1205_driver.driver.name, &client->dev,
 515                                 &x1205_rtc_ops, THIS_MODULE);
 516
 517         if (IS_ERR(rtc))
 518                 return PTR_ERR(rtc);
 519
 520         i2c_set_clientdata(client, rtc);
 521
 522         /* Check for power failures and eventualy enable the osc */
 523         if ((err = x1205_get_status(client, &sr)) == 0) {
 524                 if (sr & X1205_SR_RTCF) {
 525                         dev_err(&client->dev,
 526                                 "power failure detected, "
 527                                 "please set the clock\n");
 528                         udelay(50);
 529                         x1205_fix_osc(client);
 530                 }
 531         }
 532         else
 533                 dev_err(&client->dev, "couldn't read status\n");
 534
 535         err = x1205_sysfs_register(&client->dev);
 536         if (err)
 537                 goto exit_devreg;
 538
 539         return 0;
 540
 541 exit_devreg:
 542         rtc_device_unregister(rtc);
 543
 544         return err;
 545 }
 546
 547 static int x1205_remove(struct i2c_client *client)
 548 {
 549         struct rtc_device *rtc = i2c_get_clientdata(client);
 550
 551         rtc_device_unregister(rtc);
 552         x1205_sysfs_unregister(&client->dev);
 553         return 0;
 554 }
 555
 556 static const struct i2c_device_id x1205_id[] = {
 557         { "x1205", 0 },
 558         { }
 559 };
 560 MODULE_DEVICE_TABLE(i2c, x1205_id);
 561
 562 static struct i2c_driver x1205_driver = {
 563         .driver         = {
 564                 .name   = "rtc-x1205",
 565         },
 566         .probe          = x1205_probe,
 567         .remove         = x1205_remove,
 568         .id_table       = x1205_id,
 569 };
 570
 571 static int __init x1205_init(void)
 572 {
 573         return i2c_add_driver(&x1205_driver);
 574 }
 575
 576 static void __exit x1205_exit(void)
 577 {
 578         i2c_del_driver(&x1205_driver);
 579 }
 580
 581 MODULE_AUTHOR(
 582         "Karen Spearel <kas111 at gmail dot com>, "
 583         "Alessandro Zummo <a.zummo@towertech.it>");
 584 MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver");
 585 MODULE_LICENSE("GPL");
 586 MODULE_VERSION(DRV_VERSION);
 587
 588 module_init(x1205_init);
 589 module_exit(x1205_exit);