drivers/char/tpm/tpm_i2c_infineon.c

   1 /*
   2  * Copyright (C) 2012,2013 Infineon Technologies
   3  *
   4  * Authors:
   5  * Peter Huewe <peter.huewe@infineon.com>
   6  *
   7  * Device driver for TCG/TCPA TPM (trusted platform module).
   8  * Specifications at www.trustedcomputinggroup.org
   9  *
  10  * This device driver implements the TPM interface as defined in
  11  * the TCG TPM Interface Spec version 1.2, revision 1.0 and the
  12  * Infineon I2C Protocol Stack Specification v0.20.
  13  *
  14  * It is based on the original tpm_tis device driver from Leendert van
  15  * Dorn and Kyleen Hall.
  16  *
  17  * This program is free software; you can redistribute it and/or
  18  * modify it under the terms of the GNU General Public License as
  19  * published by the Free Software Foundation, version 2 of the
  20  * License.
  21  *
  22  *
  23  */
  24 #include <linux/i2c.h>
  25 #include <linux/module.h>
  26 #include <linux/wait.h>
  27 #include "tpm.h"
  28
  29 #define TPM_I2C_INFINEON_BUFSIZE 1260
  30
  31 /* max. number of iterations after I2C NAK */
  32 #define MAX_COUNT 3
  33
  34 #define SLEEP_DURATION_LOW 55
  35 #define SLEEP_DURATION_HI 65
  36
  37 /* max. number of iterations after I2C NAK for 'long' commands
  38  * we need this especially for sending TPM_READY, since the cleanup after the
  39  * transtion to the ready state may take some time, but it is unpredictable
  40  * how long it will take.
  41  */
  42 #define MAX_COUNT_LONG 50
  43
  44 #define SLEEP_DURATION_LONG_LOW 200
  45 #define SLEEP_DURATION_LONG_HI 220
  46
  47 /* After sending TPM_READY to 'reset' the TPM we have to sleep even longer */
  48 #define SLEEP_DURATION_RESET_LOW 2400
  49 #define SLEEP_DURATION_RESET_HI 2600
  50
  51 /* we want to use usleep_range instead of msleep for the 5ms TPM_TIMEOUT */
  52 #define TPM_TIMEOUT_US_LOW (TPM_TIMEOUT * 1000)
  53 #define TPM_TIMEOUT_US_HI  (TPM_TIMEOUT_US_LOW + 2000)
  54
  55 /* expected value for DIDVID register */
  56 #define TPM_TIS_I2C_DID_VID_9635 0xd1150b00L
  57 #define TPM_TIS_I2C_DID_VID_9645 0x001a15d1L
  58
  59 enum i2c_chip_type {
  60         SLB9635,
  61         SLB9645,
  62         UNKNOWN,
  63 };
  64
  65 struct tpm_inf_dev {
  66         struct i2c_client *client;
  67         int locality;
  68         /* In addition to the data itself, the buffer must fit the 7-bit I2C
  69          * address and the direction bit.
  70          */
  71         u8 buf[TPM_I2C_INFINEON_BUFSIZE + 1];
  72         struct tpm_chip *chip;
  73         enum i2c_chip_type chip_type;
  74         unsigned int adapterlimit;
  75 };
  76
  77 static struct tpm_inf_dev tpm_dev;
  78
  79 /*
  80  * iic_tpm_read() - read from TPM register
  81  * @addr: register address to read from
  82  * @buffer: provided by caller
  83  * @len: number of bytes to read
  84  *
  85  * Read len bytes from TPM register and put them into
  86  * buffer (little-endian format, i.e. first byte is put into buffer[0]).
  87  *
  88  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
  89  * values have to be swapped.
  90  *
  91  * NOTE: We can't unfortunately use the combined read/write functions
  92  * provided by the i2c core as the TPM currently does not support the
  93  * repeated start condition and due to it's special requirements.
  94  * The i2c_smbus* functions do not work for this chip.
  95  *
  96  * Return -EIO on error, 0 on success.
  97  */
  98 static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
  99 {
 100
 101         struct i2c_msg msg1 = {
 102                 .addr = tpm_dev.client->addr,
 103                 .len = 1,
 104                 .buf = &addr
 105         };
 106         struct i2c_msg msg2 = {
 107                 .addr = tpm_dev.client->addr,
 108                 .flags = I2C_M_RD,
 109                 .len = len,
 110                 .buf = buffer
 111         };
 112         struct i2c_msg msgs[] = {msg1, msg2};
 113
 114         int rc = 0;
 115         int count;
 116         unsigned int msglen = len;
 117
 118         /* Lock the adapter for the duration of the whole sequence. */
 119         if (!tpm_dev.client->adapter->algo->master_xfer)
 120                 return -EOPNOTSUPP;
 121         i2c_lock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);
 122
 123         if (tpm_dev.chip_type == SLB9645) {
 124                 /* use a combined read for newer chips
 125                  * unfortunately the smbus functions are not suitable due to
 126                  * the 32 byte limit of the smbus.
 127                  * retries should usually not be needed, but are kept just to
 128                  * be on the safe side.
 129                  */
 130                 for (count = 0; count < MAX_COUNT; count++) {
 131                         rc = __i2c_transfer(tpm_dev.client->adapter, msgs, 2);
 132                         if (rc > 0)
 133                                 break;  /* break here to skip sleep */
 134                         usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
 135                 }
 136         } else {
 137                 /* Expect to send one command message and one data message, but
 138                  * support looping over each or both if necessary.
 139                  */
 140                 while (len > 0) {
 141                         /* slb9635 protocol should work in all cases */
 142                         for (count = 0; count < MAX_COUNT; count++) {
 143                                 rc = __i2c_transfer(tpm_dev.client->adapter,
 144                                                     &msg1, 1);
 145                                 if (rc > 0)
 146                                         break;  /* break here to skip sleep */
 147
 148                                 usleep_range(SLEEP_DURATION_LOW,
 149                                              SLEEP_DURATION_HI);
 150                         }
 151
 152                         if (rc <= 0)
 153                                 goto out;
 154
 155                         /* After the TPM has successfully received the register
 156                          * address it needs some time, thus we're sleeping here
 157                          * again, before retrieving the data
 158                          */
 159                         for (count = 0; count < MAX_COUNT; count++) {
 160                                 if (tpm_dev.adapterlimit) {
 161                                         msglen = min_t(unsigned int,
 162                                                        tpm_dev.adapterlimit,
 163                                                        len);
 164                                         msg2.len = msglen;
 165                                 }
 166                                 usleep_range(SLEEP_DURATION_LOW,
 167                                              SLEEP_DURATION_HI);
 168                                 rc = __i2c_transfer(tpm_dev.client->adapter,
 169                                                     &msg2, 1);
 170                                 if (rc > 0) {
 171                                         /* Since len is unsigned, make doubly
 172                                          * sure we do not underflow it.
 173                                          */
 174                                         if (msglen > len)
 175                                                 len = 0;
 176                                         else
 177                                                 len -= msglen;
 178                                         msg2.buf += msglen;
 179                                         break;
 180                                 }
 181                                 /* If the I2C adapter rejected the request (e.g
 182                                  * when the quirk read_max_len < len) fall back
 183                                  * to a sane minimum value and try again.
 184                                  */
 185                                 if (rc == -EOPNOTSUPP)
 186                                         tpm_dev.adapterlimit =
 187                                                         I2C_SMBUS_BLOCK_MAX;
 188                         }
 189
 190                         if (rc <= 0)
 191                                 goto out;
 192                 }
 193         }
 194
 195 out:
 196         i2c_unlock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);
 197         /* take care of 'guard time' */
 198         usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
 199
 200         /* __i2c_transfer returns the number of successfully transferred
 201          * messages.
 202          * So rc should be greater than 0 here otherwise we have an error.
 203          */
 204         if (rc <= 0)
 205                 return -EIO;
 206
 207         return 0;
 208 }
 209
 210 static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
 211                                  unsigned int sleep_low,
 212                                  unsigned int sleep_hi, u8 max_count)
 213 {
 214         int rc = -EIO;
 215         int count;
 216
 217         struct i2c_msg msg1 = {
 218                 .addr = tpm_dev.client->addr,
 219                 .len = len + 1,
 220                 .buf = tpm_dev.buf
 221         };
 222
 223         if (len > TPM_I2C_INFINEON_BUFSIZE)
 224                 return -EINVAL;
 225
 226         if (!tpm_dev.client->adapter->algo->master_xfer)
 227                 return -EOPNOTSUPP;
 228         i2c_lock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);
 229
 230         /* prepend the 'register address' to the buffer */
 231         tpm_dev.buf[0] = addr;
 232         memcpy(&(tpm_dev.buf[1]), buffer, len);
 233
 234         /*
 235          * NOTE: We have to use these special mechanisms here and unfortunately
 236          * cannot rely on the standard behavior of i2c_transfer.
 237          * Even for newer chips the smbus functions are not
 238          * suitable due to the 32 byte limit of the smbus.
 239          */
 240         for (count = 0; count < max_count; count++) {
 241                 rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
 242                 if (rc > 0)
 243                         break;
 244                 usleep_range(sleep_low, sleep_hi);
 245         }
 246
 247         i2c_unlock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);
 248         /* take care of 'guard time' */
 249         usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
 250
 251         /* __i2c_transfer returns the number of successfully transferred
 252          * messages.
 253          * So rc should be greater than 0 here otherwise we have an error.
 254          */
 255         if (rc <= 0)
 256                 return -EIO;
 257
 258         return 0;
 259 }
 260
 261 /*
 262  * iic_tpm_write() - write to TPM register
 263  * @addr: register address to write to
 264  * @buffer: containing data to be written
 265  * @len: number of bytes to write
 266  *
 267  * Write len bytes from provided buffer to TPM register (little
 268  * endian format, i.e. buffer[0] is written as first byte).
 269  *
 270  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
 271  * values have to be swapped.
 272  *
 273  * NOTE: use this function instead of the iic_tpm_write_generic function.
 274  *
 275  * Return -EIO on error, 0 on success
 276  */
 277 static int iic_tpm_write(u8 addr, u8 *buffer, size_t len)
 278 {
 279         return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LOW,
 280                                      SLEEP_DURATION_HI, MAX_COUNT);
 281 }
 282
 283 /*
 284  * This function is needed especially for the cleanup situation after
 285  * sending TPM_READY
 286  * */
 287 static int iic_tpm_write_long(u8 addr, u8 *buffer, size_t len)
 288 {
 289         return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LONG_LOW,
 290                                      SLEEP_DURATION_LONG_HI, MAX_COUNT_LONG);
 291 }
 292
 293 enum tis_access {
 294         TPM_ACCESS_VALID = 0x80,
 295         TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
 296         TPM_ACCESS_REQUEST_PENDING = 0x04,
 297         TPM_ACCESS_REQUEST_USE = 0x02,
 298 };
 299
 300 enum tis_status {
 301         TPM_STS_VALID = 0x80,
 302         TPM_STS_COMMAND_READY = 0x40,
 303         TPM_STS_GO = 0x20,
 304         TPM_STS_DATA_AVAIL = 0x10,
 305         TPM_STS_DATA_EXPECT = 0x08,
 306 };
 307
 308 enum tis_defaults {
 309         TIS_SHORT_TIMEOUT = 750,        /* ms */
 310         TIS_LONG_TIMEOUT = 2000,        /* 2 sec */
 311 };
 312
 313 #define TPM_ACCESS(l)                   (0x0000 | ((l) << 4))
 314 #define TPM_STS(l)                      (0x0001 | ((l) << 4))
 315 #define TPM_DATA_FIFO(l)                (0x0005 | ((l) << 4))
 316 #define TPM_DID_VID(l)                  (0x0006 | ((l) << 4))
 317
 318 static bool check_locality(struct tpm_chip *chip, int loc)
 319 {
 320         u8 buf;
 321         int rc;
 322
 323         rc = iic_tpm_read(TPM_ACCESS(loc), &buf, 1);
 324         if (rc < 0)
 325                 return false;
 326
 327         if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
 328             (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
 329                 tpm_dev.locality = loc;
 330                 return true;
 331         }
 332
 333         return false;
 334 }
 335
 336 /* implementation similar to tpm_tis */
 337 static void release_locality(struct tpm_chip *chip, int loc, int force)
 338 {
 339         u8 buf;
 340         if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0)
 341                 return;
 342
 343         if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
 344             (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) {
 345                 buf = TPM_ACCESS_ACTIVE_LOCALITY;
 346                 iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
 347         }
 348 }
 349
 350 static int request_locality(struct tpm_chip *chip, int loc)
 351 {
 352         unsigned long stop;
 353         u8 buf = TPM_ACCESS_REQUEST_USE;
 354
 355         if (check_locality(chip, loc))
 356                 return loc;
 357
 358         iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
 359
 360         /* wait for burstcount */
 361         stop = jiffies + chip->timeout_a;
 362         do {
 363                 if (check_locality(chip, loc))
 364                         return loc;
 365                 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
 366         } while (time_before(jiffies, stop));
 367
 368         return -ETIME;
 369 }
 370
 371 static u8 tpm_tis_i2c_status(struct tpm_chip *chip)
 372 {
 373         /* NOTE: since I2C read may fail, return 0 in this case --> time-out */
 374         u8 buf = 0xFF;
 375         u8 i = 0;
 376
 377         do {
 378                 if (iic_tpm_read(TPM_STS(tpm_dev.locality), &buf, 1) < 0)
 379                         return 0;
 380
 381                 i++;
 382         /* if locallity is set STS should not be 0xFF */
 383         } while ((buf == 0xFF) && i < 10);
 384
 385         return buf;
 386 }
 387
 388 static void tpm_tis_i2c_ready(struct tpm_chip *chip)
 389 {
 390         /* this causes the current command to be aborted */
 391         u8 buf = TPM_STS_COMMAND_READY;
 392         iic_tpm_write_long(TPM_STS(tpm_dev.locality), &buf, 1);
 393 }
 394
 395 static ssize_t get_burstcount(struct tpm_chip *chip)
 396 {
 397         unsigned long stop;
 398         ssize_t burstcnt;
 399         u8 buf[3];
 400
 401         /* wait for burstcount */
 402         /* which timeout value, spec has 2 answers (c & d) */
 403         stop = jiffies + chip->timeout_d;
 404         do {
 405                 /* Note: STS is little endian */
 406                 if (iic_tpm_read(TPM_STS(tpm_dev.locality)+1, buf, 3) < 0)
 407                         burstcnt = 0;
 408                 else
 409                         burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0];
 410
 411                 if (burstcnt)
 412                         return burstcnt;
 413
 414                 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
 415         } while (time_before(jiffies, stop));
 416         return -EBUSY;
 417 }
 418
 419 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
 420                          int *status)
 421 {
 422         unsigned long stop;
 423
 424         /* check current status */
 425         *status = tpm_tis_i2c_status(chip);
 426         if ((*status != 0xFF) && (*status & mask) == mask)
 427                 return 0;
 428
 429         stop = jiffies + timeout;
 430         do {
 431                 /* since we just checked the status, give the TPM some time */
 432                 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
 433                 *status = tpm_tis_i2c_status(chip);
 434                 if ((*status & mask) == mask)
 435                         return 0;
 436
 437         } while (time_before(jiffies, stop));
 438
 439         return -ETIME;
 440 }
 441
 442 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
 443 {
 444         size_t size = 0;
 445         ssize_t burstcnt;
 446         u8 retries = 0;
 447         int rc;
 448
 449         while (size < count) {
 450                 burstcnt = get_burstcount(chip);
 451
 452                 /* burstcnt < 0 = TPM is busy */
 453                 if (burstcnt < 0)
 454                         return burstcnt;
 455
 456                 /* limit received data to max. left */
 457                 if (burstcnt > (count - size))
 458                         burstcnt = count - size;
 459
 460                 rc = iic_tpm_read(TPM_DATA_FIFO(tpm_dev.locality),
 461                                   &(buf[size]), burstcnt);
 462                 if (rc == 0)
 463                         size += burstcnt;
 464                 else if (rc < 0)
 465                         retries++;
 466
 467                 /* avoid endless loop in case of broken HW */
 468                 if (retries > MAX_COUNT_LONG)
 469                         return -EIO;
 470         }
 471         return size;
 472 }
 473
 474 static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 475 {
 476         int size = 0;
 477         int status;
 478         u32 expected;
 479
 480         if (count < TPM_HEADER_SIZE) {
 481                 size = -EIO;
 482                 goto out;
 483         }
 484
 485         /* read first 10 bytes, including tag, paramsize, and result */
 486         size = recv_data(chip, buf, TPM_HEADER_SIZE);
 487         if (size < TPM_HEADER_SIZE) {
 488                 dev_err(&chip->dev, "Unable to read header\n");
 489                 goto out;
 490         }
 491
 492         expected = be32_to_cpu(*(__be32 *)(buf + 2));
 493         if (((size_t) expected > count) || (expected < TPM_HEADER_SIZE)) {
 494                 size = -EIO;
 495                 goto out;
 496         }
 497
 498         size += recv_data(chip, &buf[TPM_HEADER_SIZE],
 499                           expected - TPM_HEADER_SIZE);
 500         if (size < expected) {
 501                 dev_err(&chip->dev, "Unable to read remainder of result\n");
 502                 size = -ETIME;
 503                 goto out;
 504         }
 505
 506         wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
 507         if (status & TPM_STS_DATA_AVAIL) {      /* retry? */
 508                 dev_err(&chip->dev, "Error left over data\n");
 509                 size = -EIO;
 510                 goto out;
 511         }
 512
 513 out:
 514         tpm_tis_i2c_ready(chip);
 515         /* The TPM needs some time to clean up here,
 516          * so we sleep rather than keeping the bus busy
 517          */
 518         usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
 519         release_locality(chip, tpm_dev.locality, 0);
 520         return size;
 521 }
 522
 523 static int tpm_tis_i2c_send(struct tpm_chip *chip, u8 *buf, size_t len)
 524 {
 525         int rc, status;
 526         ssize_t burstcnt;
 527         size_t count = 0;
 528         u8 retries = 0;
 529         u8 sts = TPM_STS_GO;
 530
 531         if (len > TPM_I2C_INFINEON_BUFSIZE)
 532                 return -E2BIG;
 533
 534         if (request_locality(chip, 0) < 0)
 535                 return -EBUSY;
 536
 537         status = tpm_tis_i2c_status(chip);
 538         if ((status & TPM_STS_COMMAND_READY) == 0) {
 539                 tpm_tis_i2c_ready(chip);
 540                 if (wait_for_stat
 541                     (chip, TPM_STS_COMMAND_READY,
 542                      chip->timeout_b, &status) < 0) {
 543                         rc = -ETIME;
 544                         goto out_err;
 545                 }
 546         }
 547
 548         while (count < len - 1) {
 549                 burstcnt = get_burstcount(chip);
 550
 551                 /* burstcnt < 0 = TPM is busy */
 552                 if (burstcnt < 0)
 553                         return burstcnt;
 554
 555                 if (burstcnt > (len - 1 - count))
 556                         burstcnt = len - 1 - count;
 557
 558                 rc = iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality),
 559                                    &(buf[count]), burstcnt);
 560                 if (rc == 0)
 561                         count += burstcnt;
 562                 else if (rc < 0)
 563                         retries++;
 564
 565                 /* avoid endless loop in case of broken HW */
 566                 if (retries > MAX_COUNT_LONG) {
 567                         rc = -EIO;
 568                         goto out_err;
 569                 }
 570
 571                 wait_for_stat(chip, TPM_STS_VALID,
 572                               chip->timeout_c, &status);
 573
 574                 if ((status & TPM_STS_DATA_EXPECT) == 0) {
 575                         rc = -EIO;
 576                         goto out_err;
 577                 }
 578         }
 579
 580         /* write last byte */
 581         iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality), &(buf[count]), 1);
 582         wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
 583         if ((status & TPM_STS_DATA_EXPECT) != 0) {
 584                 rc = -EIO;
 585                 goto out_err;
 586         }
 587
 588         /* go and do it */
 589         iic_tpm_write(TPM_STS(tpm_dev.locality), &sts, 1);
 590
 591         return 0;
 592 out_err:
 593         tpm_tis_i2c_ready(chip);
 594         /* The TPM needs some time to clean up here,
 595          * so we sleep rather than keeping the bus busy
 596          */
 597         usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
 598         release_locality(chip, tpm_dev.locality, 0);
 599         return rc;
 600 }
 601
 602 static bool tpm_tis_i2c_req_canceled(struct tpm_chip *chip, u8 status)
 603 {
 604         return (status == TPM_STS_COMMAND_READY);
 605 }
 606
 607 static const struct tpm_class_ops tpm_tis_i2c = {
 608         .flags = TPM_OPS_AUTO_STARTUP,
 609         .status = tpm_tis_i2c_status,
 610         .recv = tpm_tis_i2c_recv,
 611         .send = tpm_tis_i2c_send,
 612         .cancel = tpm_tis_i2c_ready,
 613         .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 614         .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 615         .req_canceled = tpm_tis_i2c_req_canceled,
 616 };
 617
 618 static int tpm_tis_i2c_init(struct device *dev)
 619 {
 620         u32 vendor;
 621         int rc = 0;
 622         struct tpm_chip *chip;
 623
 624         chip = tpmm_chip_alloc(dev, &tpm_tis_i2c);
 625         if (IS_ERR(chip))
 626                 return PTR_ERR(chip);
 627
 628         /* Default timeouts */
 629         chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 630         chip->timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
 631         chip->timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 632         chip->timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 633
 634         if (request_locality(chip, 0) != 0) {
 635                 dev_err(dev, "could not request locality\n");
 636                 rc = -ENODEV;
 637                 goto out_err;
 638         }
 639
 640         /* read four bytes from DID_VID register */
 641         if (iic_tpm_read(TPM_DID_VID(0), (u8 *)&vendor, 4) < 0) {
 642                 dev_err(dev, "could not read vendor id\n");
 643                 rc = -EIO;
 644                 goto out_release;
 645         }
 646
 647         if (vendor == TPM_TIS_I2C_DID_VID_9645) {
 648                 tpm_dev.chip_type = SLB9645;
 649         } else if (vendor == TPM_TIS_I2C_DID_VID_9635) {
 650                 tpm_dev.chip_type = SLB9635;
 651         } else {
 652                 dev_err(dev, "vendor id did not match! ID was %08x\n", vendor);
 653                 rc = -ENODEV;
 654                 goto out_release;
 655         }
 656
 657         dev_info(dev, "1.2 TPM (device-id 0x%X)\n", vendor >> 16);
 658
 659         tpm_dev.chip = chip;
 660
 661         return tpm_chip_register(chip);
 662 out_release:
 663         release_locality(chip, tpm_dev.locality, 1);
 664         tpm_dev.client = NULL;
 665 out_err:
 666         return rc;
 667 }
 668
 669 static const struct i2c_device_id tpm_tis_i2c_table[] = {
 670         {"tpm_i2c_infineon"},
 671         {"slb9635tt"},
 672         {"slb9645tt"},
 673         {},
 674 };
 675
 676 MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_table);
 677
 678 #ifdef CONFIG_OF
 679 static const struct of_device_id tpm_tis_i2c_of_match[] = {
 680         {.compatible = "infineon,tpm_i2c_infineon"},
 681         {.compatible = "infineon,slb9635tt"},
 682         {.compatible = "infineon,slb9645tt"},
 683         {},
 684 };
 685 MODULE_DEVICE_TABLE(of, tpm_tis_i2c_of_match);
 686 #endif
 687
 688 static SIMPLE_DEV_PM_OPS(tpm_tis_i2c_ops, tpm_pm_suspend, tpm_pm_resume);
 689
 690 static int tpm_tis_i2c_probe(struct i2c_client *client,
 691                              const struct i2c_device_id *id)
 692 {
 693         int rc;
 694         struct device *dev = &(client->dev);
 695
 696         if (tpm_dev.client != NULL) {
 697                 dev_err(dev, "This driver only supports one client at a time\n");
 698                 return -EBUSY;  /* We only support one client */
 699         }
 700
 701         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 702                 dev_err(dev, "no algorithms associated to the i2c bus\n");
 703                 return -ENODEV;
 704         }
 705
 706         tpm_dev.client = client;
 707         rc = tpm_tis_i2c_init(&client->dev);
 708         if (rc != 0) {
 709                 tpm_dev.client = NULL;
 710                 rc = -ENODEV;
 711         }
 712         return rc;
 713 }
 714
 715 static int tpm_tis_i2c_remove(struct i2c_client *client)
 716 {
 717         struct tpm_chip *chip = tpm_dev.chip;
 718
 719         tpm_chip_unregister(chip);
 720         release_locality(chip, tpm_dev.locality, 1);
 721         tpm_dev.client = NULL;
 722
 723         return 0;
 724 }
 725
 726 static struct i2c_driver tpm_tis_i2c_driver = {
 727         .id_table = tpm_tis_i2c_table,
 728         .probe = tpm_tis_i2c_probe,
 729         .remove = tpm_tis_i2c_remove,
 730         .driver = {
 731                    .name = "tpm_i2c_infineon",
 732                    .pm = &tpm_tis_i2c_ops,
 733                    .of_match_table = of_match_ptr(tpm_tis_i2c_of_match),
 734                    },
 735 };
 736
 737 module_i2c_driver(tpm_tis_i2c_driver);
 738 MODULE_AUTHOR("Peter Huewe <peter.huewe@infineon.com>");
 739 MODULE_DESCRIPTION("TPM TIS I2C Infineon Driver");
 740 MODULE_VERSION("2.2.0");
 741 MODULE_LICENSE("GPL");