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#define X1205_SR_AL0 0x20 /* Alarm 0 match */ 75 76#define X1205_DTR_DTR0 0x01 77#define X1205_DTR_DTR1 0x02 78#define X1205_DTR_DTR2 0x04 79 80#define X1205_HR_MIL 0x80 /* Set in ccr.hour for 24 hr mode */ 81 82#define X1205_INT_AL0E 0x20 /* Alarm 0 enable */ 83 84static struct i2c_driver x1205_driver; 85 86/* 87 * In the routines that deal directly with the x1205 hardware, we use 88 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch 89 * Epoch is initialized as 2000. Time is set to UTC. 90 */ 91static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm, 92 unsigned char reg_base) 93{ 94 unsigned char dt_addr[2] = { 0, reg_base }; 95 unsigned char buf[8]; 96 int i; 97 98 struct i2c_msg msgs[] = { 99 { client->addr, 0, 2, dt_addr }, /* setup read ptr */ 100 { client->addr, I2C_M_RD, 8, buf }, /* read date */ 101 }; 102 103 /* read date registers */ 104 if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) { 105 dev_err(&client->dev, "%s: read error\n", __func__); 106 return -EIO; 107 } 108 109 dev_dbg(&client->dev, 110 "%s: raw read data - sec=%02x, min=%02x, hr=%02x, " 111 "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n", 112 __func__, 113 buf[0], buf[1], buf[2], buf[3], 114 buf[4], buf[5], buf[6], buf[7]); 115 116 /* Mask out the enable bits if these are alarm registers */ 117 if (reg_base < X1205_CCR_BASE) 118 for (i = 0; i <= 4; i++) 119 buf[i] &= 0x7F; 120 121 tm->tm_sec = bcd2bin(buf[CCR_SEC]); 122 tm->tm_min = bcd2bin(buf[CCR_MIN]); 123 tm->tm_hour = bcd2bin(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */ 124 tm->tm_mday = bcd2bin(buf[CCR_MDAY]); 125 tm->tm_mon = bcd2bin(buf[CCR_MONTH]) - 1; /* mon is 0-11 */ 126 tm->tm_year = bcd2bin(buf[CCR_YEAR]) 127 + (bcd2bin(buf[CCR_Y2K]) * 100) - 1900; 128 tm->tm_wday = buf[CCR_WDAY]; 129 130 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 131 "mday=%d, mon=%d, year=%d, wday=%d\n", 132 __func__, 133 tm->tm_sec, tm->tm_min, tm->tm_hour, 134 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 135 136 return 0; 137} 138 139static int x1205_get_status(struct i2c_client *client, unsigned char *sr) 140{ 141 static unsigned char sr_addr[2] = { 0, X1205_REG_SR }; 142 143 struct i2c_msg msgs[] = { 144 { client->addr, 0, 2, sr_addr }, /* setup read ptr */ 145 { client->addr, I2C_M_RD, 1, sr }, /* read status */ 146 }; 147 148 /* read status register */ 149 if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) { 150 dev_err(&client->dev, "%s: read error\n", __func__); 151 return -EIO; 152 } 153 154 return 0; 155} 156 157static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm, 158 u8 reg_base, unsigned char alm_enable) 159{ 160 int i, xfer; 161 unsigned char rdata[10] = { 0, reg_base }; 162 unsigned char *buf = rdata + 2; 163 164 static const unsigned char wel[3] = { 0, X1205_REG_SR, 165 X1205_SR_WEL }; 166 167 static const unsigned char rwel[3] = { 0, X1205_REG_SR, 168 X1205_SR_WEL | X1205_SR_RWEL }; 169 170 static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 }; 171 172 dev_dbg(&client->dev, 173 "%s: sec=%d min=%d hour=%d mday=%d mon=%d year=%d wday=%d\n", 174 __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, tm->tm_mday, 175 tm->tm_mon, tm->tm_year, tm->tm_wday); 176 177 buf[CCR_SEC] = bin2bcd(tm->tm_sec); 178 buf[CCR_MIN] = bin2bcd(tm->tm_min); 179 180 /* set hour and 24hr bit */ 181 buf[CCR_HOUR] = bin2bcd(tm->tm_hour) | X1205_HR_MIL; 182 183 buf[CCR_MDAY] = bin2bcd(tm->tm_mday); 184 185 /* month, 1 - 12 */ 186 buf[CCR_MONTH] = bin2bcd(tm->tm_mon + 1); 187 188 /* year, since the rtc epoch*/ 189 buf[CCR_YEAR] = bin2bcd(tm->tm_year % 100); 190 buf[CCR_WDAY] = tm->tm_wday & 0x07; 191 buf[CCR_Y2K] = bin2bcd((tm->tm_year + 1900) / 100); 192 193 /* If writing alarm registers, set compare bits on registers 0-4 */ 194 if (reg_base < X1205_CCR_BASE) 195 for (i = 0; i <= 4; i++) 196 buf[i] |= 0x80; 197 198 /* this sequence is required to unlock the chip */ 199 if ((xfer = i2c_master_send(client, wel, 3)) != 3) { 200 dev_err(&client->dev, "%s: wel - %d\n", __func__, xfer); 201 return -EIO; 202 } 203 204 if ((xfer = i2c_master_send(client, rwel, 3)) != 3) { 205 dev_err(&client->dev, "%s: rwel - %d\n", __func__, xfer); 206 return -EIO; 207 } 208 209 xfer = i2c_master_send(client, rdata, sizeof(rdata)); 210 if (xfer != sizeof(rdata)) { 211 dev_err(&client->dev, 212 "%s: result=%d addr=%02x, data=%02x\n", 213 __func__, 214 xfer, rdata[1], rdata[2]); 215 return -EIO; 216 } 217 218 /* If we wrote to the nonvolatile region, wait 10msec for write cycle*/ 219 if (reg_base < X1205_CCR_BASE) { 220 unsigned char al0e[3] = { 0, X1205_REG_INT, 0 }; 221 222 msleep(10); 223 224 /* ...and set or clear the AL0E bit in the INT register */ 225 226 /* Need to set RWEL again as the write has cleared it */ 227 xfer = i2c_master_send(client, rwel, 3); 228 if (xfer != 3) { 229 dev_err(&client->dev, 230 "%s: aloe rwel - %d\n", 231 __func__, 232 xfer); 233 return -EIO; 234 } 235 236 if (alm_enable) 237 al0e[2] = X1205_INT_AL0E; 238 239 xfer = i2c_master_send(client, al0e, 3); 240 if (xfer != 3) { 241 dev_err(&client->dev, 242 "%s: al0e - %d\n", 243 __func__, 244 xfer); 245 return -EIO; 246 } 247 248 /* and wait 10msec again for this write to complete */ 249 msleep(10); 250 } 251 252 /* disable further writes */ 253 if ((xfer = i2c_master_send(client, diswe, 3)) != 3) { 254 dev_err(&client->dev, "%s: diswe - %d\n", __func__, xfer); 255 return -EIO; 256 } 257 258 return 0; 259} 260 261static int x1205_fix_osc(struct i2c_client *client) 262{ 263 int err; 264 struct rtc_time tm; 265 266 memset(&tm, 0, sizeof(tm)); 267 268 err = x1205_set_datetime(client, &tm, X1205_CCR_BASE, 0); 269 if (err < 0) 270 dev_err(&client->dev, "unable to restart the oscillator\n"); 271 272 return err; 273} 274 275static int x1205_get_dtrim(struct i2c_client *client, int *trim) 276{ 277 unsigned char dtr; 278 static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR }; 279 280 struct i2c_msg msgs[] = { 281 { client->addr, 0, 2, dtr_addr }, /* setup read ptr */ 282 { client->addr, I2C_M_RD, 1, &dtr }, /* read dtr */ 283 }; 284 285 /* read dtr register */ 286 if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) { 287 dev_err(&client->dev, "%s: read error\n", __func__); 288 return -EIO; 289 } 290 291 dev_dbg(&client->dev, "%s: raw dtr=%x\n", __func__, dtr); 292 293 *trim = 0; 294 295 if (dtr & X1205_DTR_DTR0) 296 *trim += 20; 297 298 if (dtr & X1205_DTR_DTR1) 299 *trim += 10; 300 301 if (dtr & X1205_DTR_DTR2) 302 *trim = -*trim; 303 304 return 0; 305} 306 307static int x1205_get_atrim(struct i2c_client *client, int *trim) 308{ 309 s8 atr; 310 static unsigned char atr_addr[2] = { 0, X1205_REG_ATR }; 311 312 struct i2c_msg msgs[] = { 313 { client->addr, 0, 2, atr_addr }, /* setup read ptr */ 314 { client->addr, I2C_M_RD, 1, &atr }, /* read atr */ 315 }; 316 317 /* read atr 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 atr=%x\n", __func__, atr); 324 325 /* atr is a two's complement value on 6 bits, 326 * perform sign extension. The formula is 327 * Catr = (atr * 0.25pF) + 11.00pF. 328 */ 329 if (atr & 0x20) 330 atr |= 0xC0; 331 332 dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __func__, atr, atr); 333 334 *trim = (atr * 250) + 11000; 335 336 dev_dbg(&client->dev, "%s: real=%d\n", __func__, *trim); 337 338 return 0; 339} 340 341struct x1205_limit 342{ 343 unsigned char reg, mask, min, max; 344}; 345 346static int x1205_validate_client(struct i2c_client *client) 347{ 348 int i, xfer; 349 350 /* Probe array. We will read the register at the specified 351 * address and check if the given bits are zero. 352 */ 353 static const unsigned char probe_zero_pattern[] = { 354 /* register, mask */ 355 X1205_REG_SR, 0x18, 356 X1205_REG_DTR, 0xF8, 357 X1205_REG_ATR, 0xC0, 358 X1205_REG_INT, 0x18, 359 X1205_REG_0, 0xFF, 360 }; 361 362 static const struct x1205_limit probe_limits_pattern[] = { 363 /* register, mask, min, max */ 364 { X1205_REG_Y2K, 0xFF, 19, 20 }, 365 { X1205_REG_DW, 0xFF, 0, 6 }, 366 { X1205_REG_YR, 0xFF, 0, 99 }, 367 { X1205_REG_MO, 0xFF, 0, 12 }, 368 { X1205_REG_DT, 0xFF, 0, 31 }, 369 { X1205_REG_HR, 0x7F, 0, 23 }, 370 { X1205_REG_MN, 0xFF, 0, 59 }, 371 { X1205_REG_SC, 0xFF, 0, 59 }, 372 { X1205_REG_Y2K1, 0xFF, 19, 20 }, 373 { X1205_REG_Y2K0, 0xFF, 19, 20 }, 374 }; 375 376 /* check that registers have bits a 0 where expected */ 377 for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) { 378 unsigned char buf; 379 380 unsigned char addr[2] = { 0, probe_zero_pattern[i] }; 381 382 struct i2c_msg msgs[2] = { 383 { client->addr, 0, 2, addr }, 384 { client->addr, I2C_M_RD, 1, &buf }, 385 }; 386 387 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) { 388 dev_err(&client->dev, 389 "%s: could not read register %x\n", 390 __func__, probe_zero_pattern[i]); 391 392 return -EIO; 393 } 394 395 if ((buf & probe_zero_pattern[i+1]) != 0) { 396 dev_err(&client->dev, 397 "%s: register=%02x, zero pattern=%d, value=%x\n", 398 __func__, probe_zero_pattern[i], i, buf); 399 400 return -ENODEV; 401 } 402 } 403 404 /* check limits (only registers with bcd values) */ 405 for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) { 406 unsigned char reg, value; 407 408 unsigned char addr[2] = { 0, probe_limits_pattern[i].reg }; 409 410 struct i2c_msg msgs[2] = { 411 { client->addr, 0, 2, addr }, 412 { client->addr, I2C_M_RD, 1, ® }, 413 }; 414 415 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) { 416 dev_err(&client->dev, 417 "%s: could not read register %x\n", 418 __func__, probe_limits_pattern[i].reg); 419 420 return -EIO; 421 } 422 423 value = bcd2bin(reg & probe_limits_pattern[i].mask); 424 425 if (value > probe_limits_pattern[i].max || 426 value < probe_limits_pattern[i].min) { 427 dev_dbg(&client->dev, 428 "%s: register=%x, lim pattern=%d, value=%d\n", 429 __func__, probe_limits_pattern[i].reg, 430 i, value); 431 432 return -ENODEV; 433 } 434 } 435 436 return 0; 437} 438 439static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 440{ 441 int err; 442 unsigned char intreg, status; 443 static unsigned char int_addr[2] = { 0, X1205_REG_INT }; 444 struct i2c_client *client = to_i2c_client(dev); 445 struct i2c_msg msgs[] = { 446 { client->addr, 0, 2, int_addr }, /* setup read ptr */ 447 { client->addr, I2C_M_RD, 1, &intreg }, /* read INT register */ 448 }; 449 450 /* read interrupt register and status register */ 451 if (i2c_transfer(client->adapter, &msgs[0], 2) != 2) { 452 dev_err(&client->dev, "%s: read error\n", __func__); 453 return -EIO; 454 } 455 err = x1205_get_status(client, &status); 456 if (err == 0) { 457 alrm->pending = (status & X1205_SR_AL0) ? 1 : 0; 458 alrm->enabled = (intreg & X1205_INT_AL0E) ? 1 : 0; 459 err = x1205_get_datetime(client, &alrm->time, X1205_ALM0_BASE); 460 } 461 return err; 462} 463 464static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 465{ 466 return x1205_set_datetime(to_i2c_client(dev), 467 &alrm->time, X1205_ALM0_BASE, alrm->enabled); 468} 469 470static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm) 471{ 472 return x1205_get_datetime(to_i2c_client(dev), 473 tm, X1205_CCR_BASE); 474} 475 476static int x1205_rtc_set_time(struct device *dev, struct rtc_time *tm) 477{ 478 return x1205_set_datetime(to_i2c_client(dev), 479 tm, X1205_CCR_BASE, 0); 480} 481 482static int x1205_rtc_proc(struct device *dev, struct seq_file *seq) 483{ 484 int err, dtrim, atrim; 485 486 if ((err = x1205_get_dtrim(to_i2c_client(dev), &dtrim)) == 0) 487 seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim); 488 489 if ((err = x1205_get_atrim(to_i2c_client(dev), &atrim)) == 0) 490 seq_printf(seq, "analog_trim\t: %d.%02d pF\n", 491 atrim / 1000, atrim % 1000); 492 return 0; 493} 494 495static const struct rtc_class_ops x1205_rtc_ops = { 496 .proc = x1205_rtc_proc, 497 .read_time = x1205_rtc_read_time, 498 .set_time = x1205_rtc_set_time, 499 .read_alarm = x1205_rtc_read_alarm, 500 .set_alarm = x1205_rtc_set_alarm, 501}; 502 503static ssize_t x1205_sysfs_show_atrim(struct device *dev, 504 struct device_attribute *attr, char *buf) 505{ 506 int err, atrim; 507 508 err = x1205_get_atrim(to_i2c_client(dev), &atrim); 509 if (err) 510 return err; 511 512 return sprintf(buf, "%d.%02d pF\n", atrim / 1000, atrim % 1000); 513} 514static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL); 515 516static ssize_t x1205_sysfs_show_dtrim(struct device *dev, 517 struct device_attribute *attr, char *buf) 518{ 519 int err, dtrim; 520 521 err = x1205_get_dtrim(to_i2c_client(dev), &dtrim); 522 if (err) 523 return err; 524 525 return sprintf(buf, "%d ppm\n", dtrim); 526} 527static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL); 528 529static int x1205_sysfs_register(struct device *dev) 530{ 531 int err; 532 533 err = device_create_file(dev, &dev_attr_atrim); 534 if (err) 535 return err; 536 537 err = device_create_file(dev, &dev_attr_dtrim); 538 if (err) 539 device_remove_file(dev, &dev_attr_atrim); 540 541 return err; 542} 543 544static void x1205_sysfs_unregister(struct device *dev) 545{ 546 device_remove_file(dev, &dev_attr_atrim); 547 device_remove_file(dev, &dev_attr_dtrim); 548} 549 550 551static int x1205_probe(struct i2c_client *client, 552 const struct i2c_device_id *id) 553{ 554 int err = 0; 555 unsigned char sr; 556 struct rtc_device *rtc; 557 558 dev_dbg(&client->dev, "%s\n", __func__); 559 560 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 561 return -ENODEV; 562 563 if (x1205_validate_client(client) < 0) 564 return -ENODEV; 565 566 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 567 568 rtc = rtc_device_register(x1205_driver.driver.name, &client->dev, 569 &x1205_rtc_ops, THIS_MODULE); 570 571 if (IS_ERR(rtc)) 572 return PTR_ERR(rtc); 573 574 i2c_set_clientdata(client, rtc); 575 576 /* Check for power failures and eventualy enable the osc */ 577 if ((err = x1205_get_status(client, &sr)) == 0) { 578 if (sr & X1205_SR_RTCF) { 579 dev_err(&client->dev, 580 "power failure detected, " 581 "please set the clock\n"); 582 udelay(50); 583 x1205_fix_osc(client); 584 } 585 } 586 else 587 dev_err(&client->dev, "couldn't read status\n"); 588 589 err = x1205_sysfs_register(&client->dev); 590 if (err) 591 goto exit_devreg; 592 593 return 0; 594 595exit_devreg: 596 rtc_device_unregister(rtc); 597 598 return err; 599} 600 601static int x1205_remove(struct i2c_client *client) 602{ 603 struct rtc_device *rtc = i2c_get_clientdata(client); 604 605 rtc_device_unregister(rtc); 606 x1205_sysfs_unregister(&client->dev); 607 return 0; 608} 609 610static const struct i2c_device_id x1205_id[] = { 611 { "x1205", 0 }, 612 { } 613}; 614MODULE_DEVICE_TABLE(i2c, x1205_id); 615 616static struct i2c_driver x1205_driver = { 617 .driver = { 618 .name = "rtc-x1205", 619 }, 620 .probe = x1205_probe, 621 .remove = x1205_remove, 622 .id_table = x1205_id, 623}; 624 625static int __init x1205_init(void) 626{ 627 return i2c_add_driver(&x1205_driver); 628} 629 630static void __exit x1205_exit(void) 631{ 632 i2c_del_driver(&x1205_driver); 633} 634 635MODULE_AUTHOR( 636 "Karen Spearel <kas111 at gmail dot com>, " 637 "Alessandro Zummo <a.zummo@towertech.it>"); 638MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver"); 639MODULE_LICENSE("GPL"); 640MODULE_VERSION(DRV_VERSION); 641 642module_init(x1205_init); 643module_exit(x1205_exit); 644