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#include <linux/module.h> 25#include <linux/bitops.h> 26 27#define DRV_VERSION "1.0.8" 28 29/* offsets into CCR area */ 30 31#define CCR_SEC 0 32#define CCR_MIN 1 33#define CCR_HOUR 2 34#define CCR_MDAY 3 35#define CCR_MONTH 4 36#define CCR_YEAR 5 37#define CCR_WDAY 6 38#define CCR_Y2K 7 39 40#define X1205_REG_SR 0x3F /* status register */ 41#define X1205_REG_Y2K 0x37 42#define X1205_REG_DW 0x36 43#define X1205_REG_YR 0x35 44#define X1205_REG_MO 0x34 45#define X1205_REG_DT 0x33 46#define X1205_REG_HR 0x32 47#define X1205_REG_MN 0x31 48#define X1205_REG_SC 0x30 49#define X1205_REG_DTR 0x13 50#define X1205_REG_ATR 0x12 51#define X1205_REG_INT 0x11 52#define X1205_REG_0 0x10 53#define X1205_REG_Y2K1 0x0F 54#define X1205_REG_DWA1 0x0E 55#define X1205_REG_YRA1 0x0D 56#define X1205_REG_MOA1 0x0C 57#define X1205_REG_DTA1 0x0B 58#define X1205_REG_HRA1 0x0A 59#define X1205_REG_MNA1 0x09 60#define X1205_REG_SCA1 0x08 61#define X1205_REG_Y2K0 0x07 62#define X1205_REG_DWA0 0x06 63#define X1205_REG_YRA0 0x05 64#define X1205_REG_MOA0 0x04 65#define X1205_REG_DTA0 0x03 66#define X1205_REG_HRA0 0x02 67#define X1205_REG_MNA0 0x01 68#define X1205_REG_SCA0 0x00 69 70#define X1205_CCR_BASE 0x30 /* Base address of CCR */ 71#define X1205_ALM0_BASE 0x00 /* Base address of ALARM0 */ 72 73#define X1205_SR_RTCF 0x01 /* Clock failure */ 74#define X1205_SR_WEL 0x02 /* Write Enable Latch */ 75#define X1205_SR_RWEL 0x04 /* Register Write Enable */ 76#define X1205_SR_AL0 0x20 /* Alarm 0 match */ 77 78#define X1205_DTR_DTR0 0x01 79#define X1205_DTR_DTR1 0x02 80#define X1205_DTR_DTR2 0x04 81 82#define X1205_HR_MIL 0x80 /* Set in ccr.hour for 24 hr mode */ 83 84#define X1205_INT_AL0E 0x20 /* Alarm 0 enable */ 85 86static struct i2c_driver x1205_driver; 87 88/* 89 * In the routines that deal directly with the x1205 hardware, we use 90 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch 91 * Epoch is initialized as 2000. Time is set to UTC. 92 */ 93static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm, 94 unsigned char reg_base) 95{ 96 unsigned char dt_addr[2] = { 0, reg_base }; 97 unsigned char buf[8]; 98 int i; 99 100 struct i2c_msg msgs[] = { 101 {/* setup read ptr */ 102 .addr = client->addr, 103 .len = 2, 104 .buf = dt_addr 105 }, 106 {/* read date */ 107 .addr = client->addr, 108 .flags = I2C_M_RD, 109 .len = 8, 110 .buf = buf 111 }, 112 }; 113 114 /* read date registers */ 115 if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) { 116 dev_err(&client->dev, "%s: read error\n", __func__); 117 return -EIO; 118 } 119 120 dev_dbg(&client->dev, 121 "%s: raw read data - sec=%02x, min=%02x, hr=%02x, " 122 "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n", 123 __func__, 124 buf[0], buf[1], buf[2], buf[3], 125 buf[4], buf[5], buf[6], buf[7]); 126 127 /* Mask out the enable bits if these are alarm registers */ 128 if (reg_base < X1205_CCR_BASE) 129 for (i = 0; i <= 4; i++) 130 buf[i] &= 0x7F; 131 132 tm->tm_sec = bcd2bin(buf[CCR_SEC]); 133 tm->tm_min = bcd2bin(buf[CCR_MIN]); 134 tm->tm_hour = bcd2bin(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */ 135 tm->tm_mday = bcd2bin(buf[CCR_MDAY]); 136 tm->tm_mon = bcd2bin(buf[CCR_MONTH]) - 1; /* mon is 0-11 */ 137 tm->tm_year = bcd2bin(buf[CCR_YEAR]) 138 + (bcd2bin(buf[CCR_Y2K]) * 100) - 1900; 139 tm->tm_wday = buf[CCR_WDAY]; 140 141 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 142 "mday=%d, mon=%d, year=%d, wday=%d\n", 143 __func__, 144 tm->tm_sec, tm->tm_min, tm->tm_hour, 145 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 146 147 return 0; 148} 149 150static int x1205_get_status(struct i2c_client *client, unsigned char *sr) 151{ 152 static unsigned char sr_addr[2] = { 0, X1205_REG_SR }; 153 154 struct i2c_msg msgs[] = { 155 { /* setup read ptr */ 156 .addr = client->addr, 157 .len = 2, 158 .buf = sr_addr 159 }, 160 { /* read status */ 161 .addr = client->addr, 162 .flags = I2C_M_RD, 163 .len = 1, 164 .buf = sr 165 }, 166 }; 167 168 /* read status register */ 169 if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) { 170 dev_err(&client->dev, "%s: read error\n", __func__); 171 return -EIO; 172 } 173 174 return 0; 175} 176 177static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm, 178 u8 reg_base, unsigned char alm_enable) 179{ 180 int i, xfer; 181 unsigned char rdata[10] = { 0, reg_base }; 182 unsigned char *buf = rdata + 2; 183 184 static const unsigned char wel[3] = { 0, X1205_REG_SR, 185 X1205_SR_WEL }; 186 187 static const unsigned char rwel[3] = { 0, X1205_REG_SR, 188 X1205_SR_WEL | X1205_SR_RWEL }; 189 190 static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 }; 191 192 dev_dbg(&client->dev, 193 "%s: sec=%d min=%d hour=%d mday=%d mon=%d year=%d wday=%d\n", 194 __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, tm->tm_mday, 195 tm->tm_mon, tm->tm_year, tm->tm_wday); 196 197 buf[CCR_SEC] = bin2bcd(tm->tm_sec); 198 buf[CCR_MIN] = bin2bcd(tm->tm_min); 199 200 /* set hour and 24hr bit */ 201 buf[CCR_HOUR] = bin2bcd(tm->tm_hour) | X1205_HR_MIL; 202 203 buf[CCR_MDAY] = bin2bcd(tm->tm_mday); 204 205 /* month, 1 - 12 */ 206 buf[CCR_MONTH] = bin2bcd(tm->tm_mon + 1); 207 208 /* year, since the rtc epoch*/ 209 buf[CCR_YEAR] = bin2bcd(tm->tm_year % 100); 210 buf[CCR_WDAY] = tm->tm_wday & 0x07; 211 buf[CCR_Y2K] = bin2bcd((tm->tm_year + 1900) / 100); 212 213 /* If writing alarm registers, set compare bits on registers 0-4 */ 214 if (reg_base < X1205_CCR_BASE) 215 for (i = 0; i <= 4; i++) 216 buf[i] |= 0x80; 217 218 /* this sequence is required to unlock the chip */ 219 xfer = i2c_master_send(client, wel, 3); 220 if (xfer != 3) { 221 dev_err(&client->dev, "%s: wel - %d\n", __func__, xfer); 222 return -EIO; 223 } 224 225 xfer = i2c_master_send(client, rwel, 3); 226 if (xfer != 3) { 227 dev_err(&client->dev, "%s: rwel - %d\n", __func__, xfer); 228 return -EIO; 229 } 230 231 xfer = i2c_master_send(client, rdata, sizeof(rdata)); 232 if (xfer != sizeof(rdata)) { 233 dev_err(&client->dev, 234 "%s: result=%d addr=%02x, data=%02x\n", 235 __func__, 236 xfer, rdata[1], rdata[2]); 237 return -EIO; 238 } 239 240 /* If we wrote to the nonvolatile region, wait 10msec for write cycle*/ 241 if (reg_base < X1205_CCR_BASE) { 242 unsigned char al0e[3] = { 0, X1205_REG_INT, 0 }; 243 244 msleep(10); 245 246 /* ...and set or clear the AL0E bit in the INT register */ 247 248 /* Need to set RWEL again as the write has cleared it */ 249 xfer = i2c_master_send(client, rwel, 3); 250 if (xfer != 3) { 251 dev_err(&client->dev, 252 "%s: aloe rwel - %d\n", 253 __func__, 254 xfer); 255 return -EIO; 256 } 257 258 if (alm_enable) 259 al0e[2] = X1205_INT_AL0E; 260 261 xfer = i2c_master_send(client, al0e, 3); 262 if (xfer != 3) { 263 dev_err(&client->dev, 264 "%s: al0e - %d\n", 265 __func__, 266 xfer); 267 return -EIO; 268 } 269 270 /* and wait 10msec again for this write to complete */ 271 msleep(10); 272 } 273 274 /* disable further writes */ 275 xfer = i2c_master_send(client, diswe, 3); 276 if (xfer != 3) { 277 dev_err(&client->dev, "%s: diswe - %d\n", __func__, xfer); 278 return -EIO; 279 } 280 281 return 0; 282} 283 284static int x1205_fix_osc(struct i2c_client *client) 285{ 286 int err; 287 struct rtc_time tm; 288 289 memset(&tm, 0, sizeof(tm)); 290 291 err = x1205_set_datetime(client, &tm, X1205_CCR_BASE, 0); 292 if (err < 0) 293 dev_err(&client->dev, "unable to restart the oscillator\n"); 294 295 return err; 296} 297 298static int x1205_get_dtrim(struct i2c_client *client, int *trim) 299{ 300 unsigned char dtr; 301 static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR }; 302 303 struct i2c_msg msgs[] = { 304 { /* setup read ptr */ 305 .addr = client->addr, 306 .len = 2, 307 .buf = dtr_addr 308 }, 309 { /* read dtr */ 310 .addr = client->addr, 311 .flags = I2C_M_RD, 312 .len = 1, 313 .buf = &dtr 314 }, 315 }; 316 317 /* read dtr register */ 318 if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) { 319 dev_err(&client->dev, "%s: read error\n", __func__); 320 return -EIO; 321 } 322 323 dev_dbg(&client->dev, "%s: raw dtr=%x\n", __func__, dtr); 324 325 *trim = 0; 326 327 if (dtr & X1205_DTR_DTR0) 328 *trim += 20; 329 330 if (dtr & X1205_DTR_DTR1) 331 *trim += 10; 332 333 if (dtr & X1205_DTR_DTR2) 334 *trim = -*trim; 335 336 return 0; 337} 338 339static int x1205_get_atrim(struct i2c_client *client, int *trim) 340{ 341 s8 atr; 342 static unsigned char atr_addr[2] = { 0, X1205_REG_ATR }; 343 344 struct i2c_msg msgs[] = { 345 {/* setup read ptr */ 346 .addr = client->addr, 347 .len = 2, 348 .buf = atr_addr 349 }, 350 {/* read atr */ 351 .addr = client->addr, 352 .flags = I2C_M_RD, 353 .len = 1, 354 .buf = &atr 355 }, 356 }; 357 358 /* read atr register */ 359 if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) { 360 dev_err(&client->dev, "%s: read error\n", __func__); 361 return -EIO; 362 } 363 364 dev_dbg(&client->dev, "%s: raw atr=%x\n", __func__, atr); 365 366 /* atr is a two's complement value on 6 bits, 367 * perform sign extension. The formula is 368 * Catr = (atr * 0.25pF) + 11.00pF. 369 */ 370 atr = sign_extend32(atr, 5); 371 372 dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __func__, atr, atr); 373 374 *trim = (atr * 250) + 11000; 375 376 dev_dbg(&client->dev, "%s: real=%d\n", __func__, *trim); 377 378 return 0; 379} 380 381struct x1205_limit { 382 unsigned char reg, mask, min, max; 383}; 384 385static int x1205_validate_client(struct i2c_client *client) 386{ 387 int i, xfer; 388 389 /* Probe array. We will read the register at the specified 390 * address and check if the given bits are zero. 391 */ 392 static const unsigned char probe_zero_pattern[] = { 393 /* register, mask */ 394 X1205_REG_SR, 0x18, 395 X1205_REG_DTR, 0xF8, 396 X1205_REG_ATR, 0xC0, 397 X1205_REG_INT, 0x18, 398 X1205_REG_0, 0xFF, 399 }; 400 401 static const struct x1205_limit probe_limits_pattern[] = { 402 /* register, mask, min, max */ 403 { X1205_REG_Y2K, 0xFF, 19, 20 }, 404 { X1205_REG_DW, 0xFF, 0, 6 }, 405 { X1205_REG_YR, 0xFF, 0, 99 }, 406 { X1205_REG_MO, 0xFF, 0, 12 }, 407 { X1205_REG_DT, 0xFF, 0, 31 }, 408 { X1205_REG_HR, 0x7F, 0, 23 }, 409 { X1205_REG_MN, 0xFF, 0, 59 }, 410 { X1205_REG_SC, 0xFF, 0, 59 }, 411 { X1205_REG_Y2K1, 0xFF, 19, 20 }, 412 { X1205_REG_Y2K0, 0xFF, 19, 20 }, 413 }; 414 415 /* check that registers have bits a 0 where expected */ 416 for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) { 417 unsigned char buf; 418 419 unsigned char addr[2] = { 0, probe_zero_pattern[i] }; 420 421 struct i2c_msg msgs[2] = { 422 { 423 .addr = client->addr, 424 .len = 2, 425 .buf = addr 426 }, 427 { 428 .addr = client->addr, 429 .flags = I2C_M_RD, 430 .len = 1, 431 .buf = &buf 432 }, 433 }; 434 435 xfer = i2c_transfer(client->adapter, msgs, 2); 436 if (xfer != 2) { 437 dev_err(&client->dev, 438 "%s: could not read register %x\n", 439 __func__, probe_zero_pattern[i]); 440 441 return -EIO; 442 } 443 444 if ((buf & probe_zero_pattern[i+1]) != 0) { 445 dev_err(&client->dev, 446 "%s: register=%02x, zero pattern=%d, value=%x\n", 447 __func__, probe_zero_pattern[i], i, buf); 448 449 return -ENODEV; 450 } 451 } 452 453 /* check limits (only registers with bcd values) */ 454 for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) { 455 unsigned char reg, value; 456 457 unsigned char addr[2] = { 0, probe_limits_pattern[i].reg }; 458 459 struct i2c_msg msgs[2] = { 460 { 461 .addr = client->addr, 462 .len = 2, 463 .buf = addr 464 }, 465 { 466 .addr = client->addr, 467 .flags = I2C_M_RD, 468 .len = 1, 469 .buf = ® 470 }, 471 }; 472 473 xfer = i2c_transfer(client->adapter, msgs, 2); 474 if (xfer != 2) { 475 dev_err(&client->dev, 476 "%s: could not read register %x\n", 477 __func__, probe_limits_pattern[i].reg); 478 479 return -EIO; 480 } 481 482 value = bcd2bin(reg & probe_limits_pattern[i].mask); 483 484 if (value > probe_limits_pattern[i].max || 485 value < probe_limits_pattern[i].min) { 486 dev_dbg(&client->dev, 487 "%s: register=%x, lim pattern=%d, value=%d\n", 488 __func__, probe_limits_pattern[i].reg, 489 i, value); 490 491 return -ENODEV; 492 } 493 } 494 495 return 0; 496} 497 498static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 499{ 500 int err; 501 unsigned char intreg, status; 502 static unsigned char int_addr[2] = { 0, X1205_REG_INT }; 503 struct i2c_client *client = to_i2c_client(dev); 504 struct i2c_msg msgs[] = { 505 { /* setup read ptr */ 506 .addr = client->addr, 507 .len = 2, 508 .buf = int_addr 509 }, 510 {/* read INT register */ 511 512 .addr = client->addr, 513 .flags = I2C_M_RD, 514 .len = 1, 515 .buf = &intreg 516 }, 517 }; 518 519 /* read interrupt register and status register */ 520 if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) { 521 dev_err(&client->dev, "%s: read error\n", __func__); 522 return -EIO; 523 } 524 err = x1205_get_status(client, &status); 525 if (err == 0) { 526 alrm->pending = (status & X1205_SR_AL0) ? 1 : 0; 527 alrm->enabled = (intreg & X1205_INT_AL0E) ? 1 : 0; 528 err = x1205_get_datetime(client, &alrm->time, X1205_ALM0_BASE); 529 } 530 return err; 531} 532 533static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 534{ 535 return x1205_set_datetime(to_i2c_client(dev), 536 &alrm->time, X1205_ALM0_BASE, alrm->enabled); 537} 538 539static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm) 540{ 541 return x1205_get_datetime(to_i2c_client(dev), 542 tm, X1205_CCR_BASE); 543} 544 545static int x1205_rtc_set_time(struct device *dev, struct rtc_time *tm) 546{ 547 return x1205_set_datetime(to_i2c_client(dev), 548 tm, X1205_CCR_BASE, 0); 549} 550 551static int x1205_rtc_proc(struct device *dev, struct seq_file *seq) 552{ 553 int err, dtrim, atrim; 554 555 err = x1205_get_dtrim(to_i2c_client(dev), &dtrim); 556 if (!err) 557 seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim); 558 559 err = x1205_get_atrim(to_i2c_client(dev), &atrim); 560 if (!err) 561 seq_printf(seq, "analog_trim\t: %d.%02d pF\n", 562 atrim / 1000, atrim % 1000); 563 return 0; 564} 565 566static const struct rtc_class_ops x1205_rtc_ops = { 567 .proc = x1205_rtc_proc, 568 .read_time = x1205_rtc_read_time, 569 .set_time = x1205_rtc_set_time, 570 .read_alarm = x1205_rtc_read_alarm, 571 .set_alarm = x1205_rtc_set_alarm, 572}; 573 574static ssize_t x1205_sysfs_show_atrim(struct device *dev, 575 struct device_attribute *attr, char *buf) 576{ 577 int err, atrim; 578 579 err = x1205_get_atrim(to_i2c_client(dev), &atrim); 580 if (err) 581 return err; 582 583 return sprintf(buf, "%d.%02d pF\n", atrim / 1000, atrim % 1000); 584} 585static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL); 586 587static ssize_t x1205_sysfs_show_dtrim(struct device *dev, 588 struct device_attribute *attr, char *buf) 589{ 590 int err, dtrim; 591 592 err = x1205_get_dtrim(to_i2c_client(dev), &dtrim); 593 if (err) 594 return err; 595 596 return sprintf(buf, "%d ppm\n", dtrim); 597} 598static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL); 599 600static int x1205_sysfs_register(struct device *dev) 601{ 602 int err; 603 604 err = device_create_file(dev, &dev_attr_atrim); 605 if (err) 606 return err; 607 608 err = device_create_file(dev, &dev_attr_dtrim); 609 if (err) 610 device_remove_file(dev, &dev_attr_atrim); 611 612 return err; 613} 614 615static void x1205_sysfs_unregister(struct device *dev) 616{ 617 device_remove_file(dev, &dev_attr_atrim); 618 device_remove_file(dev, &dev_attr_dtrim); 619} 620 621 622static int x1205_probe(struct i2c_client *client, 623 const struct i2c_device_id *id) 624{ 625 int err = 0; 626 unsigned char sr; 627 struct rtc_device *rtc; 628 629 dev_dbg(&client->dev, "%s\n", __func__); 630 631 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 632 return -ENODEV; 633 634 if (x1205_validate_client(client) < 0) 635 return -ENODEV; 636 637 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 638 639 rtc = devm_rtc_device_register(&client->dev, x1205_driver.driver.name, 640 &x1205_rtc_ops, THIS_MODULE); 641 642 if (IS_ERR(rtc)) 643 return PTR_ERR(rtc); 644 645 i2c_set_clientdata(client, rtc); 646 647 /* Check for power failures and eventually enable the osc */ 648 err = x1205_get_status(client, &sr); 649 if (!err) { 650 if (sr & X1205_SR_RTCF) { 651 dev_err(&client->dev, 652 "power failure detected, " 653 "please set the clock\n"); 654 udelay(50); 655 x1205_fix_osc(client); 656 } 657 } else { 658 dev_err(&client->dev, "couldn't read status\n"); 659 } 660 661 err = x1205_sysfs_register(&client->dev); 662 if (err) 663 dev_err(&client->dev, "Unable to create sysfs entries\n"); 664 665 return 0; 666} 667 668static int x1205_remove(struct i2c_client *client) 669{ 670 x1205_sysfs_unregister(&client->dev); 671 return 0; 672} 673 674static const struct i2c_device_id x1205_id[] = { 675 { "x1205", 0 }, 676 { } 677}; 678MODULE_DEVICE_TABLE(i2c, x1205_id); 679 680static struct i2c_driver x1205_driver = { 681 .driver = { 682 .name = "rtc-x1205", 683 }, 684 .probe = x1205_probe, 685 .remove = x1205_remove, 686 .id_table = x1205_id, 687}; 688 689module_i2c_driver(x1205_driver); 690 691MODULE_AUTHOR( 692 "Karen Spearel <kas111 at gmail dot com>, " 693 "Alessandro Zummo <a.zummo@towertech.it>"); 694MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver"); 695MODULE_LICENSE("GPL"); 696MODULE_VERSION(DRV_VERSION); 697