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 "1.0.7" 26 27 /* Addresses to scan: none. This chip is located at 28 * 0x6f and uses a two bytes register addressing. 29 * Two bytes need to be written to read a single register, 30 * while most other chips just require one and take the second 31 * one as the data to be written. To prevent corrupting 32 * unknown chips, the user must explicitly set the probe parameter. 33 */ 34 35 static const unsigned short normal_i2c[] = { I2C_CLIENT_END }; 36 37 /* Insmod parameters */ 38 I2C_CLIENT_INSMOD; 39 40 /* offsets into CCR area */ 41 42 #define CCR_SEC 0 43 #define CCR_MIN 1 44 #define CCR_HOUR 2 45 #define CCR_MDAY 3 46 #define CCR_MONTH 4 47 #define CCR_YEAR 5 48 #define CCR_WDAY 6 49 #define CCR_Y2K 7 50 51 #define X1205_REG_SR 0x3F /* status register */ 52 #define X1205_REG_Y2K 0x37 53 #define X1205_REG_DW 0x36 54 #define X1205_REG_YR 0x35 55 #define X1205_REG_MO 0x34 56 #define X1205_REG_DT 0x33 57 #define X1205_REG_HR 0x32 58 #define X1205_REG_MN 0x31 59 #define X1205_REG_SC 0x30 60 #define X1205_REG_DTR 0x13 61 #define X1205_REG_ATR 0x12 62 #define X1205_REG_INT 0x11 63 #define X1205_REG_0 0x10 64 #define X1205_REG_Y2K1 0x0F 65 #define X1205_REG_DWA1 0x0E 66 #define X1205_REG_YRA1 0x0D 67 #define X1205_REG_MOA1 0x0C 68 #define X1205_REG_DTA1 0x0B 69 #define X1205_REG_HRA1 0x0A 70 #define X1205_REG_MNA1 0x09 71 #define X1205_REG_SCA1 0x08 72 #define X1205_REG_Y2K0 0x07 73 #define X1205_REG_DWA0 0x06 74 #define X1205_REG_YRA0 0x05 75 #define X1205_REG_MOA0 0x04 76 #define X1205_REG_DTA0 0x03 77 #define X1205_REG_HRA0 0x02 78 #define X1205_REG_MNA0 0x01 79 #define X1205_REG_SCA0 0x00 80 81 #define X1205_CCR_BASE 0x30 /* Base address of CCR */ 82 #define X1205_ALM0_BASE 0x00 /* Base address of ALARM0 */ 83 84 #define X1205_SR_RTCF 0x01 /* Clock failure */ 85 #define X1205_SR_WEL 0x02 /* Write Enable Latch */ 86 #define X1205_SR_RWEL 0x04 /* Register Write Enable */ 87 88 #define X1205_DTR_DTR0 0x01 89 #define X1205_DTR_DTR1 0x02 90 #define X1205_DTR_DTR2 0x04 91 92 #define X1205_HR_MIL 0x80 /* Set in ccr.hour for 24 hr mode */ 93 94 /* Prototypes */ 95 static int x1205_attach(struct i2c_adapter *adapter); 96 static int x1205_detach(struct i2c_client *client); 97 static int x1205_probe(struct i2c_adapter *adapter, int address, int kind); 98 99 static struct i2c_driver x1205_driver = { 100 .driver = { 101 .name = "x1205", 102 }, 103 .id = I2C_DRIVERID_X1205, 104 .attach_adapter = &x1205_attach, 105 .detach_client = &x1205_detach, 106 }; 107 108 /* 109 * In the routines that deal directly with the x1205 hardware, we use 110 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch 111 * Epoch is initialized as 2000. Time is set to UTC. 112 */ 113 static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm, 114 unsigned char reg_base) 115 { 116 unsigned char dt_addr[2] = { 0, reg_base }; 117 118 unsigned char buf[8]; 119 120 struct i2c_msg msgs[] = { 121 { client->addr, 0, 2, dt_addr }, /* setup read ptr */ 122 { client->addr, I2C_M_RD, 8, buf }, /* read date */ 123 }; 124 125 /* read date registers */ 126 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 127 dev_err(&client->dev, "%s: read error\n", __FUNCTION__); 128 return -EIO; 129 } 130 131 dev_dbg(&client->dev, 132 "%s: raw read data - sec=%02x, min=%02x, hr=%02x, " 133 "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n", 134 __FUNCTION__, 135 buf[0], buf[1], buf[2], buf[3], 136 buf[4], buf[5], buf[6], buf[7]); 137 138 tm->tm_sec = BCD2BIN(buf[CCR_SEC]); 139 tm->tm_min = BCD2BIN(buf[CCR_MIN]); 140 tm->tm_hour = BCD2BIN(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */ 141 tm->tm_mday = BCD2BIN(buf[CCR_MDAY]); 142 tm->tm_mon = BCD2BIN(buf[CCR_MONTH]) - 1; /* mon is 0-11 */ 143 tm->tm_year = BCD2BIN(buf[CCR_YEAR]) 144 + (BCD2BIN(buf[CCR_Y2K]) * 100) - 1900; 145 tm->tm_wday = buf[CCR_WDAY]; 146 147 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 148 "mday=%d, mon=%d, year=%d, wday=%d\n", 149 __FUNCTION__, 150 tm->tm_sec, tm->tm_min, tm->tm_hour, 151 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 152 153 return 0; 154 } 155 156 static int x1205_get_status(struct i2c_client *client, unsigned char *sr) 157 { 158 static unsigned char sr_addr[2] = { 0, X1205_REG_SR }; 159 160 struct i2c_msg msgs[] = { 161 { client->addr, 0, 2, sr_addr }, /* setup read ptr */ 162 { client->addr, I2C_M_RD, 1, sr }, /* read status */ 163 }; 164 165 /* read status register */ 166 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 167 dev_err(&client->dev, "%s: read error\n", __FUNCTION__); 168 return -EIO; 169 } 170 171 return 0; 172 } 173 174 static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm, 175 int datetoo, u8 reg_base) 176 { 177 int i, xfer; 178 unsigned char buf[8]; 179 180 static const unsigned char wel[3] = { 0, X1205_REG_SR, 181 X1205_SR_WEL }; 182 183 static const unsigned char rwel[3] = { 0, X1205_REG_SR, 184 X1205_SR_WEL | X1205_SR_RWEL }; 185 186 static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 }; 187 188 dev_dbg(&client->dev, 189 "%s: secs=%d, mins=%d, hours=%d\n", 190 __FUNCTION__, 191 tm->tm_sec, tm->tm_min, tm->tm_hour); 192 193 buf[CCR_SEC] = BIN2BCD(tm->tm_sec); 194 buf[CCR_MIN] = BIN2BCD(tm->tm_min); 195 196 /* set hour and 24hr bit */ 197 buf[CCR_HOUR] = BIN2BCD(tm->tm_hour) | X1205_HR_MIL; 198 199 /* should we also set the date? */ 200 if (datetoo) { 201 dev_dbg(&client->dev, 202 "%s: mday=%d, mon=%d, year=%d, wday=%d\n", 203 __FUNCTION__, 204 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 205 206 buf[CCR_MDAY] = BIN2BCD(tm->tm_mday); 207 208 /* month, 1 - 12 */ 209 buf[CCR_MONTH] = BIN2BCD(tm->tm_mon + 1); 210 211 /* year, since the rtc epoch*/ 212 buf[CCR_YEAR] = BIN2BCD(tm->tm_year % 100); 213 buf[CCR_WDAY] = tm->tm_wday & 0x07; 214 buf[CCR_Y2K] = BIN2BCD(tm->tm_year / 100); 215 } 216 217 /* this sequence is required to unlock the chip */ 218 if ((xfer = i2c_master_send(client, wel, 3)) != 3) { 219 dev_err(&client->dev, "%s: wel - %d\n", __FUNCTION__, xfer); 220 return -EIO; 221 } 222 223 if ((xfer = i2c_master_send(client, rwel, 3)) != 3) { 224 dev_err(&client->dev, "%s: rwel - %d\n", __FUNCTION__, xfer); 225 return -EIO; 226 } 227 228 /* write register's data */ 229 for (i = 0; i < (datetoo ? 8 : 3); i++) { 230 unsigned char rdata[3] = { 0, reg_base + i, buf[i] }; 231 232 xfer = i2c_master_send(client, rdata, 3); 233 if (xfer != 3) { 234 dev_err(&client->dev, 235 "%s: xfer=%d addr=%02x, data=%02x\n", 236 __FUNCTION__, 237 xfer, rdata[1], rdata[2]); 238 return -EIO; 239 } 240 }; 241 242 /* disable further writes */ 243 if ((xfer = i2c_master_send(client, diswe, 3)) != 3) { 244 dev_err(&client->dev, "%s: diswe - %d\n", __FUNCTION__, xfer); 245 return -EIO; 246 } 247 248 return 0; 249 } 250 251 static int x1205_fix_osc(struct i2c_client *client) 252 { 253 int err; 254 struct rtc_time tm; 255 256 tm.tm_hour = tm.tm_min = tm.tm_sec = 0; 257 258 if ((err = x1205_set_datetime(client, &tm, 0, X1205_CCR_BASE)) < 0) 259 dev_err(&client->dev, 260 "unable to restart the oscillator\n"); 261 262 return err; 263 } 264 265 static int x1205_get_dtrim(struct i2c_client *client, int *trim) 266 { 267 unsigned char dtr; 268 static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR }; 269 270 struct i2c_msg msgs[] = { 271 { client->addr, 0, 2, dtr_addr }, /* setup read ptr */ 272 { client->addr, I2C_M_RD, 1, &dtr }, /* read dtr */ 273 }; 274 275 /* read dtr register */ 276 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 277 dev_err(&client->dev, "%s: read error\n", __FUNCTION__); 278 return -EIO; 279 } 280 281 dev_dbg(&client->dev, "%s: raw dtr=%x\n", __FUNCTION__, dtr); 282 283 *trim = 0; 284 285 if (dtr & X1205_DTR_DTR0) 286 *trim += 20; 287 288 if (dtr & X1205_DTR_DTR1) 289 *trim += 10; 290 291 if (dtr & X1205_DTR_DTR2) 292 *trim = -*trim; 293 294 return 0; 295 } 296 297 static int x1205_get_atrim(struct i2c_client *client, int *trim) 298 { 299 s8 atr; 300 static unsigned char atr_addr[2] = { 0, X1205_REG_ATR }; 301 302 struct i2c_msg msgs[] = { 303 { client->addr, 0, 2, atr_addr }, /* setup read ptr */ 304 { client->addr, I2C_M_RD, 1, &atr }, /* read atr */ 305 }; 306 307 /* read atr register */ 308 if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) { 309 dev_err(&client->dev, "%s: read error\n", __FUNCTION__); 310 return -EIO; 311 } 312 313 dev_dbg(&client->dev, "%s: raw atr=%x\n", __FUNCTION__, atr); 314 315 /* atr is a two's complement value on 6 bits, 316 * perform sign extension. The formula is 317 * Catr = (atr * 0.25pF) + 11.00pF. 318 */ 319 if (atr & 0x20) 320 atr |= 0xC0; 321 322 dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __FUNCTION__, atr, atr); 323 324 *trim = (atr * 250) + 11000; 325 326 dev_dbg(&client->dev, "%s: real=%d\n", __FUNCTION__, *trim); 327 328 return 0; 329 } 330 331 struct x1205_limit 332 { 333 unsigned char reg, mask, min, max; 334 }; 335 336 static int x1205_validate_client(struct i2c_client *client) 337 { 338 int i, xfer; 339 340 /* Probe array. We will read the register at the specified 341 * address and check if the given bits are zero. 342 */ 343 static const unsigned char probe_zero_pattern[] = { 344 /* register, mask */ 345 X1205_REG_SR, 0x18, 346 X1205_REG_DTR, 0xF8, 347 X1205_REG_ATR, 0xC0, 348 X1205_REG_INT, 0x18, 349 X1205_REG_0, 0xFF, 350 }; 351 352 static const struct x1205_limit probe_limits_pattern[] = { 353 /* register, mask, min, max */ 354 { X1205_REG_Y2K, 0xFF, 19, 20 }, 355 { X1205_REG_DW, 0xFF, 0, 6 }, 356 { X1205_REG_YR, 0xFF, 0, 99 }, 357 { X1205_REG_MO, 0xFF, 0, 12 }, 358 { X1205_REG_DT, 0xFF, 0, 31 }, 359 { X1205_REG_HR, 0x7F, 0, 23 }, 360 { X1205_REG_MN, 0xFF, 0, 59 }, 361 { X1205_REG_SC, 0xFF, 0, 59 }, 362 { X1205_REG_Y2K1, 0xFF, 19, 20 }, 363 { X1205_REG_Y2K0, 0xFF, 19, 20 }, 364 }; 365 366 /* check that registers have bits a 0 where expected */ 367 for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) { 368 unsigned char buf; 369 370 unsigned char addr[2] = { 0, probe_zero_pattern[i] }; 371 372 struct i2c_msg msgs[2] = { 373 { client->addr, 0, 2, addr }, 374 { client->addr, I2C_M_RD, 1, &buf }, 375 }; 376 377 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) { 378 dev_err(&client->dev, 379 "%s: could not read register %x\n", 380 __FUNCTION__, probe_zero_pattern[i]); 381 382 return -EIO; 383 } 384 385 if ((buf & probe_zero_pattern[i+1]) != 0) { 386 dev_err(&client->dev, 387 "%s: register=%02x, zero pattern=%d, value=%x\n", 388 __FUNCTION__, probe_zero_pattern[i], i, buf); 389 390 return -ENODEV; 391 } 392 } 393 394 /* check limits (only registers with bcd values) */ 395 for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) { 396 unsigned char reg, value; 397 398 unsigned char addr[2] = { 0, probe_limits_pattern[i].reg }; 399 400 struct i2c_msg msgs[2] = { 401 { client->addr, 0, 2, addr }, 402 { client->addr, I2C_M_RD, 1, ® }, 403 }; 404 405 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) { 406 dev_err(&client->dev, 407 "%s: could not read register %x\n", 408 __FUNCTION__, probe_limits_pattern[i].reg); 409 410 return -EIO; 411 } 412 413 value = BCD2BIN(reg & probe_limits_pattern[i].mask); 414 415 if (value > probe_limits_pattern[i].max || 416 value < probe_limits_pattern[i].min) { 417 dev_dbg(&client->dev, 418 "%s: register=%x, lim pattern=%d, value=%d\n", 419 __FUNCTION__, probe_limits_pattern[i].reg, 420 i, value); 421 422 return -ENODEV; 423 } 424 } 425 426 return 0; 427 } 428 429 static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 430 { 431 return x1205_get_datetime(to_i2c_client(dev), 432 &alrm->time, X1205_ALM0_BASE); 433 } 434 435 static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 436 { 437 return x1205_set_datetime(to_i2c_client(dev), 438 &alrm->time, 1, X1205_ALM0_BASE); 439 } 440 441 static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm) 442 { 443 return x1205_get_datetime(to_i2c_client(dev), 444 tm, X1205_CCR_BASE); 445 } 446 447 static int x1205_rtc_set_time(struct device *dev, struct rtc_time *tm) 448 { 449 return x1205_set_datetime(to_i2c_client(dev), 450 tm, 1, X1205_CCR_BASE); 451 } 452 453 static int x1205_rtc_proc(struct device *dev, struct seq_file *seq) 454 { 455 int err, dtrim, atrim; 456 457 if ((err = x1205_get_dtrim(to_i2c_client(dev), &dtrim)) == 0) 458 seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim); 459 460 if ((err = x1205_get_atrim(to_i2c_client(dev), &atrim)) == 0) 461 seq_printf(seq, "analog_trim\t: %d.%02d pF\n", 462 atrim / 1000, atrim % 1000); 463 return 0; 464 } 465 466 static const struct rtc_class_ops x1205_rtc_ops = { 467 .proc = x1205_rtc_proc, 468 .read_time = x1205_rtc_read_time, 469 .set_time = x1205_rtc_set_time, 470 .read_alarm = x1205_rtc_read_alarm, 471 .set_alarm = x1205_rtc_set_alarm, 472 }; 473 474 static ssize_t x1205_sysfs_show_atrim(struct device *dev, 475 struct device_attribute *attr, char *buf) 476 { 477 int err, atrim; 478 479 err = x1205_get_atrim(to_i2c_client(dev), &atrim); 480 if (err) 481 return err; 482 483 return sprintf(buf, "%d.%02d pF\n", atrim / 1000, atrim % 1000); 484 } 485 static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL); 486 487 static ssize_t x1205_sysfs_show_dtrim(struct device *dev, 488 struct device_attribute *attr, char *buf) 489 { 490 int err, dtrim; 491 492 err = x1205_get_dtrim(to_i2c_client(dev), &dtrim); 493 if (err) 494 return err; 495 496 return sprintf(buf, "%d ppm\n", dtrim); 497 } 498 static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL); 499 500 static int x1205_attach(struct i2c_adapter *adapter) 501 { 502 return i2c_probe(adapter, &addr_data, x1205_probe); 503 } 504 505 static int x1205_probe(struct i2c_adapter *adapter, int address, int kind) 506 { 507 int err = 0; 508 unsigned char sr; 509 struct i2c_client *client; 510 struct rtc_device *rtc; 511 512 dev_dbg(&adapter->dev, "%s\n", __FUNCTION__); 513 514 if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) { 515 err = -ENODEV; 516 goto exit; 517 } 518 519 if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) { 520 err = -ENOMEM; 521 goto exit; 522 } 523 524 /* I2C client */ 525 client->addr = address; 526 client->driver = &x1205_driver; 527 client->adapter = adapter; 528 529 strlcpy(client->name, x1205_driver.driver.name, I2C_NAME_SIZE); 530 531 /* Verify the chip is really an X1205 */ 532 if (kind < 0) { 533 if (x1205_validate_client(client) < 0) { 534 err = -ENODEV; 535 goto exit_kfree; 536 } 537 } 538 539 /* Inform the i2c layer */ 540 if ((err = i2c_attach_client(client))) 541 goto exit_kfree; 542 543 dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); 544 545 rtc = rtc_device_register(x1205_driver.driver.name, &client->dev, 546 &x1205_rtc_ops, THIS_MODULE); 547 548 if (IS_ERR(rtc)) { 549 err = PTR_ERR(rtc); 550 goto exit_detach; 551 } 552 553 i2c_set_clientdata(client, rtc); 554 555 /* Check for power failures and eventualy enable the osc */ 556 if ((err = x1205_get_status(client, &sr)) == 0) { 557 if (sr & X1205_SR_RTCF) { 558 dev_err(&client->dev, 559 "power failure detected, " 560 "please set the clock\n"); 561 udelay(50); 562 x1205_fix_osc(client); 563 } 564 } 565 else 566 dev_err(&client->dev, "couldn't read status\n"); 567 568 err = device_create_file(&client->dev, &dev_attr_atrim); 569 if (err) goto exit_devreg; 570 err = device_create_file(&client->dev, &dev_attr_dtrim); 571 if (err) goto exit_atrim; 572 573 return 0; 574 575 exit_atrim: 576 device_remove_file(&client->dev, &dev_attr_atrim); 577 578 exit_devreg: 579 rtc_device_unregister(rtc); 580 581 exit_detach: 582 i2c_detach_client(client); 583 584 exit_kfree: 585 kfree(client); 586 587 exit: 588 return err; 589 } 590 591 static int x1205_detach(struct i2c_client *client) 592 { 593 int err; 594 struct rtc_device *rtc = i2c_get_clientdata(client); 595 596 if (rtc) 597 rtc_device_unregister(rtc); 598 599 if ((err = i2c_detach_client(client))) 600 return err; 601 602 kfree(client); 603 604 return 0; 605 } 606 607 static int __init x1205_init(void) 608 { 609 return i2c_add_driver(&x1205_driver); 610 } 611 612 static void __exit x1205_exit(void) 613 { 614 i2c_del_driver(&x1205_driver); 615 } 616 617 MODULE_AUTHOR( 618 "Karen Spearel <kas111 at gmail dot com>, " 619 "Alessandro Zummo <a.zummo@towertech.it>"); 620 MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver"); 621 MODULE_LICENSE("GPL"); 622 MODULE_VERSION(DRV_VERSION); 623 624 module_init(x1205_init); 625 module_exit(x1205_exit); 626