1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2012,2013 Infineon Technologies 4 * 5 * Authors: 6 * Peter Huewe <peter.huewe@infineon.com> 7 * 8 * Device driver for TCG/TCPA TPM (trusted platform module). 9 * Specifications at www.trustedcomputinggroup.org 10 * 11 * This device driver implements the TPM interface as defined in 12 * the TCG TPM Interface Spec version 1.2, revision 1.0 and the 13 * Infineon I2C Protocol Stack Specification v0.20. 14 * 15 * It is based on the original tpm_tis device driver from Leendert van 16 * Dorn and Kyleen Hall. 17 */ 18 #include <linux/i2c.h> 19 #include <linux/module.h> 20 #include <linux/wait.h> 21 #include "tpm.h" 22 23 #define TPM_I2C_INFINEON_BUFSIZE 1260 24 25 /* max. number of iterations after I2C NAK */ 26 #define MAX_COUNT 3 27 28 #define SLEEP_DURATION_LOW 55 29 #define SLEEP_DURATION_HI 65 30 31 /* max. number of iterations after I2C NAK for 'long' commands 32 * we need this especially for sending TPM_READY, since the cleanup after the 33 * transtion to the ready state may take some time, but it is unpredictable 34 * how long it will take. 35 */ 36 #define MAX_COUNT_LONG 50 37 38 #define SLEEP_DURATION_LONG_LOW 200 39 #define SLEEP_DURATION_LONG_HI 220 40 41 /* After sending TPM_READY to 'reset' the TPM we have to sleep even longer */ 42 #define SLEEP_DURATION_RESET_LOW 2400 43 #define SLEEP_DURATION_RESET_HI 2600 44 45 /* we want to use usleep_range instead of msleep for the 5ms TPM_TIMEOUT */ 46 #define TPM_TIMEOUT_US_LOW (TPM_TIMEOUT * 1000) 47 #define TPM_TIMEOUT_US_HI (TPM_TIMEOUT_US_LOW + 2000) 48 49 /* expected value for DIDVID register */ 50 #define TPM_TIS_I2C_DID_VID_9635 0xd1150b00L 51 #define TPM_TIS_I2C_DID_VID_9645 0x001a15d1L 52 53 enum i2c_chip_type { 54 SLB9635, 55 SLB9645, 56 UNKNOWN, 57 }; 58 59 struct tpm_inf_dev { 60 struct i2c_client *client; 61 int locality; 62 /* In addition to the data itself, the buffer must fit the 7-bit I2C 63 * address and the direction bit. 64 */ 65 u8 buf[TPM_I2C_INFINEON_BUFSIZE + 1]; 66 struct tpm_chip *chip; 67 enum i2c_chip_type chip_type; 68 unsigned int adapterlimit; 69 }; 70 71 static struct tpm_inf_dev tpm_dev; 72 73 /* 74 * iic_tpm_read() - read from TPM register 75 * @addr: register address to read from 76 * @buffer: provided by caller 77 * @len: number of bytes to read 78 * 79 * Read len bytes from TPM register and put them into 80 * buffer (little-endian format, i.e. first byte is put into buffer[0]). 81 * 82 * NOTE: TPM is big-endian for multi-byte values. Multi-byte 83 * values have to be swapped. 84 * 85 * NOTE: We can't unfortunately use the combined read/write functions 86 * provided by the i2c core as the TPM currently does not support the 87 * repeated start condition and due to it's special requirements. 88 * The i2c_smbus* functions do not work for this chip. 89 * 90 * Return -EIO on error, 0 on success. 91 */ 92 static int iic_tpm_read(u8 addr, u8 *buffer, size_t len) 93 { 94 95 struct i2c_msg msg1 = { 96 .addr = tpm_dev.client->addr, 97 .len = 1, 98 .buf = &addr 99 }; 100 struct i2c_msg msg2 = { 101 .addr = tpm_dev.client->addr, 102 .flags = I2C_M_RD, 103 .len = len, 104 .buf = buffer 105 }; 106 struct i2c_msg msgs[] = {msg1, msg2}; 107 108 int rc = 0; 109 int count; 110 unsigned int msglen = len; 111 112 /* Lock the adapter for the duration of the whole sequence. */ 113 if (!tpm_dev.client->adapter->algo->master_xfer) 114 return -EOPNOTSUPP; 115 i2c_lock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT); 116 117 if (tpm_dev.chip_type == SLB9645) { 118 /* use a combined read for newer chips 119 * unfortunately the smbus functions are not suitable due to 120 * the 32 byte limit of the smbus. 121 * retries should usually not be needed, but are kept just to 122 * be on the safe side. 123 */ 124 for (count = 0; count < MAX_COUNT; count++) { 125 rc = __i2c_transfer(tpm_dev.client->adapter, msgs, 2); 126 if (rc > 0) 127 break; /* break here to skip sleep */ 128 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI); 129 } 130 } else { 131 /* Expect to send one command message and one data message, but 132 * support looping over each or both if necessary. 133 */ 134 while (len > 0) { 135 /* slb9635 protocol should work in all cases */ 136 for (count = 0; count < MAX_COUNT; count++) { 137 rc = __i2c_transfer(tpm_dev.client->adapter, 138 &msg1, 1); 139 if (rc > 0) 140 break; /* break here to skip sleep */ 141 142 usleep_range(SLEEP_DURATION_LOW, 143 SLEEP_DURATION_HI); 144 } 145 146 if (rc <= 0) 147 goto out; 148 149 /* After the TPM has successfully received the register 150 * address it needs some time, thus we're sleeping here 151 * again, before retrieving the data 152 */ 153 for (count = 0; count < MAX_COUNT; count++) { 154 if (tpm_dev.adapterlimit) { 155 msglen = min_t(unsigned int, 156 tpm_dev.adapterlimit, 157 len); 158 msg2.len = msglen; 159 } 160 usleep_range(SLEEP_DURATION_LOW, 161 SLEEP_DURATION_HI); 162 rc = __i2c_transfer(tpm_dev.client->adapter, 163 &msg2, 1); 164 if (rc > 0) { 165 /* Since len is unsigned, make doubly 166 * sure we do not underflow it. 167 */ 168 if (msglen > len) 169 len = 0; 170 else 171 len -= msglen; 172 msg2.buf += msglen; 173 break; 174 } 175 /* If the I2C adapter rejected the request (e.g 176 * when the quirk read_max_len < len) fall back 177 * to a sane minimum value and try again. 178 */ 179 if (rc == -EOPNOTSUPP) 180 tpm_dev.adapterlimit = 181 I2C_SMBUS_BLOCK_MAX; 182 } 183 184 if (rc <= 0) 185 goto out; 186 } 187 } 188 189 out: 190 i2c_unlock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT); 191 /* take care of 'guard time' */ 192 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI); 193 194 /* __i2c_transfer returns the number of successfully transferred 195 * messages. 196 * So rc should be greater than 0 here otherwise we have an error. 197 */ 198 if (rc <= 0) 199 return -EIO; 200 201 return 0; 202 } 203 204 static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len, 205 unsigned int sleep_low, 206 unsigned int sleep_hi, u8 max_count) 207 { 208 int rc = -EIO; 209 int count; 210 211 struct i2c_msg msg1 = { 212 .addr = tpm_dev.client->addr, 213 .len = len + 1, 214 .buf = tpm_dev.buf 215 }; 216 217 if (len > TPM_I2C_INFINEON_BUFSIZE) 218 return -EINVAL; 219 220 if (!tpm_dev.client->adapter->algo->master_xfer) 221 return -EOPNOTSUPP; 222 i2c_lock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT); 223 224 /* prepend the 'register address' to the buffer */ 225 tpm_dev.buf[0] = addr; 226 memcpy(&(tpm_dev.buf[1]), buffer, len); 227 228 /* 229 * NOTE: We have to use these special mechanisms here and unfortunately 230 * cannot rely on the standard behavior of i2c_transfer. 231 * Even for newer chips the smbus functions are not 232 * suitable due to the 32 byte limit of the smbus. 233 */ 234 for (count = 0; count < max_count; count++) { 235 rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1); 236 if (rc > 0) 237 break; 238 usleep_range(sleep_low, sleep_hi); 239 } 240 241 i2c_unlock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT); 242 /* take care of 'guard time' */ 243 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI); 244 245 /* __i2c_transfer returns the number of successfully transferred 246 * messages. 247 * So rc should be greater than 0 here otherwise we have an error. 248 */ 249 if (rc <= 0) 250 return -EIO; 251 252 return 0; 253 } 254 255 /* 256 * iic_tpm_write() - write to TPM register 257 * @addr: register address to write to 258 * @buffer: containing data to be written 259 * @len: number of bytes to write 260 * 261 * Write len bytes from provided buffer to TPM register (little 262 * endian format, i.e. buffer[0] is written as first byte). 263 * 264 * NOTE: TPM is big-endian for multi-byte values. Multi-byte 265 * values have to be swapped. 266 * 267 * NOTE: use this function instead of the iic_tpm_write_generic function. 268 * 269 * Return -EIO on error, 0 on success 270 */ 271 static int iic_tpm_write(u8 addr, u8 *buffer, size_t len) 272 { 273 return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LOW, 274 SLEEP_DURATION_HI, MAX_COUNT); 275 } 276 277 /* 278 * This function is needed especially for the cleanup situation after 279 * sending TPM_READY 280 * */ 281 static int iic_tpm_write_long(u8 addr, u8 *buffer, size_t len) 282 { 283 return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LONG_LOW, 284 SLEEP_DURATION_LONG_HI, MAX_COUNT_LONG); 285 } 286 287 enum tis_access { 288 TPM_ACCESS_VALID = 0x80, 289 TPM_ACCESS_ACTIVE_LOCALITY = 0x20, 290 TPM_ACCESS_REQUEST_PENDING = 0x04, 291 TPM_ACCESS_REQUEST_USE = 0x02, 292 }; 293 294 enum tis_status { 295 TPM_STS_VALID = 0x80, 296 TPM_STS_COMMAND_READY = 0x40, 297 TPM_STS_GO = 0x20, 298 TPM_STS_DATA_AVAIL = 0x10, 299 TPM_STS_DATA_EXPECT = 0x08, 300 }; 301 302 enum tis_defaults { 303 TIS_SHORT_TIMEOUT = 750, /* ms */ 304 TIS_LONG_TIMEOUT = 2000, /* 2 sec */ 305 }; 306 307 #define TPM_ACCESS(l) (0x0000 | ((l) << 4)) 308 #define TPM_STS(l) (0x0001 | ((l) << 4)) 309 #define TPM_DATA_FIFO(l) (0x0005 | ((l) << 4)) 310 #define TPM_DID_VID(l) (0x0006 | ((l) << 4)) 311 312 static bool check_locality(struct tpm_chip *chip, int loc) 313 { 314 u8 buf; 315 int rc; 316 317 rc = iic_tpm_read(TPM_ACCESS(loc), &buf, 1); 318 if (rc < 0) 319 return false; 320 321 if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) == 322 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) { 323 tpm_dev.locality = loc; 324 return true; 325 } 326 327 return false; 328 } 329 330 /* implementation similar to tpm_tis */ 331 static void release_locality(struct tpm_chip *chip, int loc, int force) 332 { 333 u8 buf; 334 if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0) 335 return; 336 337 if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) == 338 (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) { 339 buf = TPM_ACCESS_ACTIVE_LOCALITY; 340 iic_tpm_write(TPM_ACCESS(loc), &buf, 1); 341 } 342 } 343 344 static int request_locality(struct tpm_chip *chip, int loc) 345 { 346 unsigned long stop; 347 u8 buf = TPM_ACCESS_REQUEST_USE; 348 349 if (check_locality(chip, loc)) 350 return loc; 351 352 iic_tpm_write(TPM_ACCESS(loc), &buf, 1); 353 354 /* wait for burstcount */ 355 stop = jiffies + chip->timeout_a; 356 do { 357 if (check_locality(chip, loc)) 358 return loc; 359 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI); 360 } while (time_before(jiffies, stop)); 361 362 return -ETIME; 363 } 364 365 static u8 tpm_tis_i2c_status(struct tpm_chip *chip) 366 { 367 /* NOTE: since I2C read may fail, return 0 in this case --> time-out */ 368 u8 buf = 0xFF; 369 u8 i = 0; 370 371 do { 372 if (iic_tpm_read(TPM_STS(tpm_dev.locality), &buf, 1) < 0) 373 return 0; 374 375 i++; 376 /* if locallity is set STS should not be 0xFF */ 377 } while ((buf == 0xFF) && i < 10); 378 379 return buf; 380 } 381 382 static void tpm_tis_i2c_ready(struct tpm_chip *chip) 383 { 384 /* this causes the current command to be aborted */ 385 u8 buf = TPM_STS_COMMAND_READY; 386 iic_tpm_write_long(TPM_STS(tpm_dev.locality), &buf, 1); 387 } 388 389 static ssize_t get_burstcount(struct tpm_chip *chip) 390 { 391 unsigned long stop; 392 ssize_t burstcnt; 393 u8 buf[3]; 394 395 /* wait for burstcount */ 396 /* which timeout value, spec has 2 answers (c & d) */ 397 stop = jiffies + chip->timeout_d; 398 do { 399 /* Note: STS is little endian */ 400 if (iic_tpm_read(TPM_STS(tpm_dev.locality)+1, buf, 3) < 0) 401 burstcnt = 0; 402 else 403 burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0]; 404 405 if (burstcnt) 406 return burstcnt; 407 408 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI); 409 } while (time_before(jiffies, stop)); 410 return -EBUSY; 411 } 412 413 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout, 414 int *status) 415 { 416 unsigned long stop; 417 418 /* check current status */ 419 *status = tpm_tis_i2c_status(chip); 420 if ((*status != 0xFF) && (*status & mask) == mask) 421 return 0; 422 423 stop = jiffies + timeout; 424 do { 425 /* since we just checked the status, give the TPM some time */ 426 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI); 427 *status = tpm_tis_i2c_status(chip); 428 if ((*status & mask) == mask) 429 return 0; 430 431 } while (time_before(jiffies, stop)); 432 433 return -ETIME; 434 } 435 436 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count) 437 { 438 size_t size = 0; 439 ssize_t burstcnt; 440 u8 retries = 0; 441 int rc; 442 443 while (size < count) { 444 burstcnt = get_burstcount(chip); 445 446 /* burstcnt < 0 = TPM is busy */ 447 if (burstcnt < 0) 448 return burstcnt; 449 450 /* limit received data to max. left */ 451 if (burstcnt > (count - size)) 452 burstcnt = count - size; 453 454 rc = iic_tpm_read(TPM_DATA_FIFO(tpm_dev.locality), 455 &(buf[size]), burstcnt); 456 if (rc == 0) 457 size += burstcnt; 458 else if (rc < 0) 459 retries++; 460 461 /* avoid endless loop in case of broken HW */ 462 if (retries > MAX_COUNT_LONG) 463 return -EIO; 464 } 465 return size; 466 } 467 468 static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count) 469 { 470 int size = 0; 471 int status; 472 u32 expected; 473 474 if (count < TPM_HEADER_SIZE) { 475 size = -EIO; 476 goto out; 477 } 478 479 /* read first 10 bytes, including tag, paramsize, and result */ 480 size = recv_data(chip, buf, TPM_HEADER_SIZE); 481 if (size < TPM_HEADER_SIZE) { 482 dev_err(&chip->dev, "Unable to read header\n"); 483 goto out; 484 } 485 486 expected = be32_to_cpu(*(__be32 *)(buf + 2)); 487 if (((size_t) expected > count) || (expected < TPM_HEADER_SIZE)) { 488 size = -EIO; 489 goto out; 490 } 491 492 size += recv_data(chip, &buf[TPM_HEADER_SIZE], 493 expected - TPM_HEADER_SIZE); 494 if (size < expected) { 495 dev_err(&chip->dev, "Unable to read remainder of result\n"); 496 size = -ETIME; 497 goto out; 498 } 499 500 wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status); 501 if (status & TPM_STS_DATA_AVAIL) { /* retry? */ 502 dev_err(&chip->dev, "Error left over data\n"); 503 size = -EIO; 504 goto out; 505 } 506 507 out: 508 tpm_tis_i2c_ready(chip); 509 /* The TPM needs some time to clean up here, 510 * so we sleep rather than keeping the bus busy 511 */ 512 usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI); 513 release_locality(chip, tpm_dev.locality, 0); 514 return size; 515 } 516 517 static int tpm_tis_i2c_send(struct tpm_chip *chip, u8 *buf, size_t len) 518 { 519 int rc, status; 520 ssize_t burstcnt; 521 size_t count = 0; 522 u8 retries = 0; 523 u8 sts = TPM_STS_GO; 524 525 if (len > TPM_I2C_INFINEON_BUFSIZE) 526 return -E2BIG; 527 528 if (request_locality(chip, 0) < 0) 529 return -EBUSY; 530 531 status = tpm_tis_i2c_status(chip); 532 if ((status & TPM_STS_COMMAND_READY) == 0) { 533 tpm_tis_i2c_ready(chip); 534 if (wait_for_stat 535 (chip, TPM_STS_COMMAND_READY, 536 chip->timeout_b, &status) < 0) { 537 rc = -ETIME; 538 goto out_err; 539 } 540 } 541 542 while (count < len - 1) { 543 burstcnt = get_burstcount(chip); 544 545 /* burstcnt < 0 = TPM is busy */ 546 if (burstcnt < 0) 547 return burstcnt; 548 549 if (burstcnt > (len - 1 - count)) 550 burstcnt = len - 1 - count; 551 552 rc = iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality), 553 &(buf[count]), burstcnt); 554 if (rc == 0) 555 count += burstcnt; 556 else if (rc < 0) 557 retries++; 558 559 /* avoid endless loop in case of broken HW */ 560 if (retries > MAX_COUNT_LONG) { 561 rc = -EIO; 562 goto out_err; 563 } 564 565 wait_for_stat(chip, TPM_STS_VALID, 566 chip->timeout_c, &status); 567 568 if ((status & TPM_STS_DATA_EXPECT) == 0) { 569 rc = -EIO; 570 goto out_err; 571 } 572 } 573 574 /* write last byte */ 575 iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality), &(buf[count]), 1); 576 wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status); 577 if ((status & TPM_STS_DATA_EXPECT) != 0) { 578 rc = -EIO; 579 goto out_err; 580 } 581 582 /* go and do it */ 583 iic_tpm_write(TPM_STS(tpm_dev.locality), &sts, 1); 584 585 return 0; 586 out_err: 587 tpm_tis_i2c_ready(chip); 588 /* The TPM needs some time to clean up here, 589 * so we sleep rather than keeping the bus busy 590 */ 591 usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI); 592 release_locality(chip, tpm_dev.locality, 0); 593 return rc; 594 } 595 596 static bool tpm_tis_i2c_req_canceled(struct tpm_chip *chip, u8 status) 597 { 598 return (status == TPM_STS_COMMAND_READY); 599 } 600 601 static const struct tpm_class_ops tpm_tis_i2c = { 602 .flags = TPM_OPS_AUTO_STARTUP, 603 .status = tpm_tis_i2c_status, 604 .recv = tpm_tis_i2c_recv, 605 .send = tpm_tis_i2c_send, 606 .cancel = tpm_tis_i2c_ready, 607 .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID, 608 .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID, 609 .req_canceled = tpm_tis_i2c_req_canceled, 610 }; 611 612 static int tpm_tis_i2c_init(struct device *dev) 613 { 614 u32 vendor; 615 int rc = 0; 616 struct tpm_chip *chip; 617 618 chip = tpmm_chip_alloc(dev, &tpm_tis_i2c); 619 if (IS_ERR(chip)) 620 return PTR_ERR(chip); 621 622 /* Default timeouts */ 623 chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT); 624 chip->timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT); 625 chip->timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT); 626 chip->timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT); 627 628 if (request_locality(chip, 0) != 0) { 629 dev_err(dev, "could not request locality\n"); 630 rc = -ENODEV; 631 goto out_err; 632 } 633 634 /* read four bytes from DID_VID register */ 635 if (iic_tpm_read(TPM_DID_VID(0), (u8 *)&vendor, 4) < 0) { 636 dev_err(dev, "could not read vendor id\n"); 637 rc = -EIO; 638 goto out_release; 639 } 640 641 if (vendor == TPM_TIS_I2C_DID_VID_9645) { 642 tpm_dev.chip_type = SLB9645; 643 } else if (vendor == TPM_TIS_I2C_DID_VID_9635) { 644 tpm_dev.chip_type = SLB9635; 645 } else { 646 dev_err(dev, "vendor id did not match! ID was %08x\n", vendor); 647 rc = -ENODEV; 648 goto out_release; 649 } 650 651 dev_info(dev, "1.2 TPM (device-id 0x%X)\n", vendor >> 16); 652 653 tpm_dev.chip = chip; 654 655 return tpm_chip_register(chip); 656 out_release: 657 release_locality(chip, tpm_dev.locality, 1); 658 tpm_dev.client = NULL; 659 out_err: 660 return rc; 661 } 662 663 static const struct i2c_device_id tpm_tis_i2c_table[] = { 664 {"tpm_i2c_infineon"}, 665 {"slb9635tt"}, 666 {"slb9645tt"}, 667 {}, 668 }; 669 670 MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_table); 671 672 #ifdef CONFIG_OF 673 static const struct of_device_id tpm_tis_i2c_of_match[] = { 674 {.compatible = "infineon,tpm_i2c_infineon"}, 675 {.compatible = "infineon,slb9635tt"}, 676 {.compatible = "infineon,slb9645tt"}, 677 {}, 678 }; 679 MODULE_DEVICE_TABLE(of, tpm_tis_i2c_of_match); 680 #endif 681 682 static SIMPLE_DEV_PM_OPS(tpm_tis_i2c_ops, tpm_pm_suspend, tpm_pm_resume); 683 684 static int tpm_tis_i2c_probe(struct i2c_client *client) 685 { 686 int rc; 687 struct device *dev = &(client->dev); 688 689 if (tpm_dev.client != NULL) { 690 dev_err(dev, "This driver only supports one client at a time\n"); 691 return -EBUSY; /* We only support one client */ 692 } 693 694 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { 695 dev_err(dev, "no algorithms associated to the i2c bus\n"); 696 return -ENODEV; 697 } 698 699 tpm_dev.client = client; 700 rc = tpm_tis_i2c_init(&client->dev); 701 if (rc != 0) { 702 tpm_dev.client = NULL; 703 rc = -ENODEV; 704 } 705 return rc; 706 } 707 708 static void tpm_tis_i2c_remove(struct i2c_client *client) 709 { 710 struct tpm_chip *chip = tpm_dev.chip; 711 712 tpm_chip_unregister(chip); 713 release_locality(chip, tpm_dev.locality, 1); 714 tpm_dev.client = NULL; 715 } 716 717 static struct i2c_driver tpm_tis_i2c_driver = { 718 .id_table = tpm_tis_i2c_table, 719 .probe = tpm_tis_i2c_probe, 720 .remove = tpm_tis_i2c_remove, 721 .driver = { 722 .name = "tpm_i2c_infineon", 723 .pm = &tpm_tis_i2c_ops, 724 .of_match_table = of_match_ptr(tpm_tis_i2c_of_match), 725 }, 726 }; 727 728 module_i2c_driver(tpm_tis_i2c_driver); 729 MODULE_AUTHOR("Peter Huewe <peter.huewe@infineon.com>"); 730 MODULE_DESCRIPTION("TPM TIS I2C Infineon Driver"); 731 MODULE_VERSION("2.2.0"); 732 MODULE_LICENSE("GPL"); 733