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 /* max. buffer size supported by our TPM */
  30 #define TPM_BUFSIZE 1260
  31
  32 /* max. number of iterations after I2C NAK */
  33 #define MAX_COUNT 3
  34
  35 #define SLEEP_DURATION_LOW 55
  36 #define SLEEP_DURATION_HI 65
  37
  38 /* max. number of iterations after I2C NAK for 'long' commands
  39  * we need this especially for sending TPM_READY, since the cleanup after the
  40  * transtion to the ready state may take some time, but it is unpredictable
  41  * how long it will take.
  42  */
  43 #define MAX_COUNT_LONG 50
  44
  45 #define SLEEP_DURATION_LONG_LOW 200
  46 #define SLEEP_DURATION_LONG_HI 220
  47
  48 /* After sending TPM_READY to 'reset' the TPM we have to sleep even longer */
  49 #define SLEEP_DURATION_RESET_LOW 2400
  50 #define SLEEP_DURATION_RESET_HI 2600
  51
  52 /* we want to use usleep_range instead of msleep for the 5ms TPM_TIMEOUT */
  53 #define TPM_TIMEOUT_US_LOW (TPM_TIMEOUT * 1000)
  54 #define TPM_TIMEOUT_US_HI  (TPM_TIMEOUT_US_LOW + 2000)
  55
  56 /* expected value for DIDVID register */
  57 #define TPM_TIS_I2C_DID_VID_9635 0xd1150b00L
  58 #define TPM_TIS_I2C_DID_VID_9645 0x001a15d1L
  59
  60 enum i2c_chip_type {
  61         SLB9635,
  62         SLB9645,
  63         UNKNOWN,
  64 };
  65
  66 /* Structure to store I2C TPM specific stuff */
  67 struct tpm_inf_dev {
  68         struct i2c_client *client;
  69         int locality;
  70         u8 buf[TPM_BUFSIZE + sizeof(u8)]; /* max. buffer size + addr */
  71         struct tpm_chip *chip;
  72         enum i2c_chip_type chip_type;
  73         unsigned int adapterlimit;
  74 };
  75
  76 static struct tpm_inf_dev tpm_dev;
  77
  78 /*
  79  * iic_tpm_read() - read from TPM register
  80  * @addr: register address to read from
  81  * @buffer: provided by caller
  82  * @len: number of bytes to read
  83  *
  84  * Read len bytes from TPM register and put them into
  85  * buffer (little-endian format, i.e. first byte is put into buffer[0]).
  86  *
  87  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
  88  * values have to be swapped.
  89  *
  90  * NOTE: We can't unfortunately use the combined read/write functions
  91  * provided by the i2c core as the TPM currently does not support the
  92  * repeated start condition and due to it's special requirements.
  93  * The i2c_smbus* functions do not work for this chip.
  94  *
  95  * Return -EIO on error, 0 on success.
  96  */
  97 static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
  98 {
  99
 100         struct i2c_msg msg1 = {
 101                 .addr = tpm_dev.client->addr,
 102                 .len = 1,
 103                 .buf = &addr
 104         };
 105         struct i2c_msg msg2 = {
 106                 .addr = tpm_dev.client->addr,
 107                 .flags = I2C_M_RD,
 108                 .len = len,
 109                 .buf = buffer
 110         };
 111         struct i2c_msg msgs[] = {msg1, msg2};
 112
 113         int rc = 0;
 114         int count;
 115         unsigned int msglen = len;
 116
 117         /* Lock the adapter for the duration of the whole sequence. */
 118         if (!tpm_dev.client->adapter->algo->master_xfer)
 119                 return -EOPNOTSUPP;
 120         i2c_lock_adapter(tpm_dev.client->adapter);
 121
 122         if (tpm_dev.chip_type == SLB9645) {
 123                 /* use a combined read for newer chips
 124                  * unfortunately the smbus functions are not suitable due to
 125                  * the 32 byte limit of the smbus.
 126                  * retries should usually not be needed, but are kept just to
 127                  * be on the safe side.
 128                  */
 129                 for (count = 0; count < MAX_COUNT; count++) {
 130                         rc = __i2c_transfer(tpm_dev.client->adapter, msgs, 2);
 131                         if (rc > 0)
 132                                 break;  /* break here to skip sleep */
 133                         usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
 134                 }
 135         } else {
 136                 /* Expect to send one command message and one data message, but
 137                  * support looping over each or both if necessary.
 138                  */
 139                 while (len > 0) {
 140                         /* slb9635 protocol should work in all cases */
 141                         for (count = 0; count < MAX_COUNT; count++) {
 142                                 rc = __i2c_transfer(tpm_dev.client->adapter,
 143                                                     &msg1, 1);
 144                                 if (rc > 0)
 145                                         break;  /* break here to skip sleep */
 146
 147                                 usleep_range(SLEEP_DURATION_LOW,
 148                                              SLEEP_DURATION_HI);
 149                         }
 150
 151                         if (rc <= 0)
 152                                 goto out;
 153
 154                         /* After the TPM has successfully received the register
 155                          * address it needs some time, thus we're sleeping here
 156                          * again, before retrieving the data
 157                          */
 158                         for (count = 0; count < MAX_COUNT; count++) {
 159                                 if (tpm_dev.adapterlimit) {
 160                                         msglen = min_t(unsigned int,
 161                                                        tpm_dev.adapterlimit,
 162                                                        len);
 163                                         msg2.len = msglen;
 164                                 }
 165                                 usleep_range(SLEEP_DURATION_LOW,
 166                                              SLEEP_DURATION_HI);
 167                                 rc = __i2c_transfer(tpm_dev.client->adapter,
 168                                                     &msg2, 1);
 169                                 if (rc > 0) {
 170                                         /* Since len is unsigned, make doubly
 171                                          * sure we do not underflow it.
 172                                          */
 173                                         if (msglen > len)
 174                                                 len = 0;
 175                                         else
 176                                                 len -= msglen;
 177                                         msg2.buf += msglen;
 178                                         break;
 179                                 }
 180                                 /* If the I2C adapter rejected the request (e.g
 181                                  * when the quirk read_max_len < len) fall back
 182                                  * to a sane minimum value and try again.
 183                                  */
 184                                 if (rc == -EOPNOTSUPP)
 185                                         tpm_dev.adapterlimit =
 186                                                         I2C_SMBUS_BLOCK_MAX;
 187                         }
 188
 189                         if (rc <= 0)
 190                                 goto out;
 191                 }
 192         }
 193
 194 out:
 195         i2c_unlock_adapter(tpm_dev.client->adapter);
 196         /* take care of 'guard time' */
 197         usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
 198
 199         /* __i2c_transfer returns the number of successfully transferred
 200          * messages.
 201          * So rc should be greater than 0 here otherwise we have an error.
 202          */
 203         if (rc <= 0)
 204                 return -EIO;
 205
 206         return 0;
 207 }
 208
 209 static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
 210                                  unsigned int sleep_low,
 211                                  unsigned int sleep_hi, u8 max_count)
 212 {
 213         int rc = -EIO;
 214         int count;
 215
 216         struct i2c_msg msg1 = {
 217                 .addr = tpm_dev.client->addr,
 218                 .len = len + 1,
 219                 .buf = tpm_dev.buf
 220         };
 221
 222         if (len > TPM_BUFSIZE)
 223                 return -EINVAL;
 224
 225         if (!tpm_dev.client->adapter->algo->master_xfer)
 226                 return -EOPNOTSUPP;
 227         i2c_lock_adapter(tpm_dev.client->adapter);
 228
 229         /* prepend the 'register address' to the buffer */
 230         tpm_dev.buf[0] = addr;
 231         memcpy(&(tpm_dev.buf[1]), buffer, len);
 232
 233         /*
 234          * NOTE: We have to use these special mechanisms here and unfortunately
 235          * cannot rely on the standard behavior of i2c_transfer.
 236          * Even for newer chips the smbus functions are not
 237          * suitable due to the 32 byte limit of the smbus.
 238          */
 239         for (count = 0; count < max_count; count++) {
 240                 rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
 241                 if (rc > 0)
 242                         break;
 243                 usleep_range(sleep_low, sleep_hi);
 244         }
 245
 246         i2c_unlock_adapter(tpm_dev.client->adapter);
 247         /* take care of 'guard time' */
 248         usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
 249
 250         /* __i2c_transfer returns the number of successfully transferred
 251          * messages.
 252          * So rc should be greater than 0 here otherwise we have an error.
 253          */
 254         if (rc <= 0)
 255                 return -EIO;
 256
 257         return 0;
 258 }
 259
 260 /*
 261  * iic_tpm_write() - write to TPM register
 262  * @addr: register address to write to
 263  * @buffer: containing data to be written
 264  * @len: number of bytes to write
 265  *
 266  * Write len bytes from provided buffer to TPM register (little
 267  * endian format, i.e. buffer[0] is written as first byte).
 268  *
 269  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
 270  * values have to be swapped.
 271  *
 272  * NOTE: use this function instead of the iic_tpm_write_generic function.
 273  *
 274  * Return -EIO on error, 0 on success
 275  */
 276 static int iic_tpm_write(u8 addr, u8 *buffer, size_t len)
 277 {
 278         return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LOW,
 279                                      SLEEP_DURATION_HI, MAX_COUNT);
 280 }
 281
 282 /*
 283  * This function is needed especially for the cleanup situation after
 284  * sending TPM_READY
 285  * */
 286 static int iic_tpm_write_long(u8 addr, u8 *buffer, size_t len)
 287 {
 288         return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LONG_LOW,
 289                                      SLEEP_DURATION_LONG_HI, MAX_COUNT_LONG);
 290 }
 291
 292 enum tis_access {
 293         TPM_ACCESS_VALID = 0x80,
 294         TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
 295         TPM_ACCESS_REQUEST_PENDING = 0x04,
 296         TPM_ACCESS_REQUEST_USE = 0x02,
 297 };
 298
 299 enum tis_status {
 300         TPM_STS_VALID = 0x80,
 301         TPM_STS_COMMAND_READY = 0x40,
 302         TPM_STS_GO = 0x20,
 303         TPM_STS_DATA_AVAIL = 0x10,
 304         TPM_STS_DATA_EXPECT = 0x08,
 305 };
 306
 307 enum tis_defaults {
 308         TIS_SHORT_TIMEOUT = 750,        /* ms */
 309         TIS_LONG_TIMEOUT = 2000,        /* 2 sec */
 310 };
 311
 312 #define TPM_ACCESS(l)                   (0x0000 | ((l) << 4))
 313 #define TPM_STS(l)                      (0x0001 | ((l) << 4))
 314 #define TPM_DATA_FIFO(l)                (0x0005 | ((l) << 4))
 315 #define TPM_DID_VID(l)                  (0x0006 | ((l) << 4))
 316
 317 static bool check_locality(struct tpm_chip *chip, int loc)
 318 {
 319         u8 buf;
 320         int rc;
 321
 322         rc = iic_tpm_read(TPM_ACCESS(loc), &buf, 1);
 323         if (rc < 0)
 324                 return false;
 325
 326         if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
 327             (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
 328                 tpm_dev.locality = loc;
 329                 return true;
 330         }
 331
 332         return false;
 333 }
 334
 335 /* implementation similar to tpm_tis */
 336 static void release_locality(struct tpm_chip *chip, int loc, int force)
 337 {
 338         u8 buf;
 339         if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0)
 340                 return;
 341
 342         if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
 343             (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) {
 344                 buf = TPM_ACCESS_ACTIVE_LOCALITY;
 345                 iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
 346         }
 347 }
 348
 349 static int request_locality(struct tpm_chip *chip, int loc)
 350 {
 351         unsigned long stop;
 352         u8 buf = TPM_ACCESS_REQUEST_USE;
 353
 354         if (check_locality(chip, loc))
 355                 return loc;
 356
 357         iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
 358
 359         /* wait for burstcount */
 360         stop = jiffies + chip->timeout_a;
 361         do {
 362                 if (check_locality(chip, loc))
 363                         return loc;
 364                 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
 365         } while (time_before(jiffies, stop));
 366
 367         return -ETIME;
 368 }
 369
 370 static u8 tpm_tis_i2c_status(struct tpm_chip *chip)
 371 {
 372         /* NOTE: since I2C read may fail, return 0 in this case --> time-out */
 373         u8 buf = 0xFF;
 374         u8 i = 0;
 375
 376         do {
 377                 if (iic_tpm_read(TPM_STS(tpm_dev.locality), &buf, 1) < 0)
 378                         return 0;
 379
 380                 i++;
 381         /* if locallity is set STS should not be 0xFF */
 382         } while ((buf == 0xFF) && i < 10);
 383
 384         return buf;
 385 }
 386
 387 static void tpm_tis_i2c_ready(struct tpm_chip *chip)
 388 {
 389         /* this causes the current command to be aborted */
 390         u8 buf = TPM_STS_COMMAND_READY;
 391         iic_tpm_write_long(TPM_STS(tpm_dev.locality), &buf, 1);
 392 }
 393
 394 static ssize_t get_burstcount(struct tpm_chip *chip)
 395 {
 396         unsigned long stop;
 397         ssize_t burstcnt;
 398         u8 buf[3];
 399
 400         /* wait for burstcount */
 401         /* which timeout value, spec has 2 answers (c & d) */
 402         stop = jiffies + chip->timeout_d;
 403         do {
 404                 /* Note: STS is little endian */
 405                 if (iic_tpm_read(TPM_STS(tpm_dev.locality)+1, buf, 3) < 0)
 406                         burstcnt = 0;
 407                 else
 408                         burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0];
 409
 410                 if (burstcnt)
 411                         return burstcnt;
 412
 413                 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
 414         } while (time_before(jiffies, stop));
 415         return -EBUSY;
 416 }
 417
 418 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
 419                          int *status)
 420 {
 421         unsigned long stop;
 422
 423         /* check current status */
 424         *status = tpm_tis_i2c_status(chip);
 425         if ((*status != 0xFF) && (*status & mask) == mask)
 426                 return 0;
 427
 428         stop = jiffies + timeout;
 429         do {
 430                 /* since we just checked the status, give the TPM some time */
 431                 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
 432                 *status = tpm_tis_i2c_status(chip);
 433                 if ((*status & mask) == mask)
 434                         return 0;
 435
 436         } while (time_before(jiffies, stop));
 437
 438         return -ETIME;
 439 }
 440
 441 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
 442 {
 443         size_t size = 0;
 444         ssize_t burstcnt;
 445         u8 retries = 0;
 446         int rc;
 447
 448         while (size < count) {
 449                 burstcnt = get_burstcount(chip);
 450
 451                 /* burstcnt < 0 = TPM is busy */
 452                 if (burstcnt < 0)
 453                         return burstcnt;
 454
 455                 /* limit received data to max. left */
 456                 if (burstcnt > (count - size))
 457                         burstcnt = count - size;
 458
 459                 rc = iic_tpm_read(TPM_DATA_FIFO(tpm_dev.locality),
 460                                   &(buf[size]), burstcnt);
 461                 if (rc == 0)
 462                         size += burstcnt;
 463                 else if (rc < 0)
 464                         retries++;
 465
 466                 /* avoid endless loop in case of broken HW */
 467                 if (retries > MAX_COUNT_LONG)
 468                         return -EIO;
 469         }
 470         return size;
 471 }
 472
 473 static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 474 {
 475         int size = 0;
 476         int expected, status;
 477
 478         if (count < TPM_HEADER_SIZE) {
 479                 size = -EIO;
 480                 goto out;
 481         }
 482
 483         /* read first 10 bytes, including tag, paramsize, and result */
 484         size = recv_data(chip, buf, TPM_HEADER_SIZE);
 485         if (size < TPM_HEADER_SIZE) {
 486                 dev_err(&chip->dev, "Unable to read header\n");
 487                 goto out;
 488         }
 489
 490         expected = be32_to_cpu(*(__be32 *)(buf + 2));
 491         if ((size_t) expected > count) {
 492                 size = -EIO;
 493                 goto out;
 494         }
 495
 496         size += recv_data(chip, &buf[TPM_HEADER_SIZE],
 497                           expected - TPM_HEADER_SIZE);
 498         if (size < expected) {
 499                 dev_err(&chip->dev, "Unable to read remainder of result\n");
 500                 size = -ETIME;
 501                 goto out;
 502         }
 503
 504         wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
 505         if (status & TPM_STS_DATA_AVAIL) {      /* retry? */
 506                 dev_err(&chip->dev, "Error left over data\n");
 507                 size = -EIO;
 508                 goto out;
 509         }
 510
 511 out:
 512         tpm_tis_i2c_ready(chip);
 513         /* The TPM needs some time to clean up here,
 514          * so we sleep rather than keeping the bus busy
 515          */
 516         usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
 517         release_locality(chip, tpm_dev.locality, 0);
 518         return size;
 519 }
 520
 521 static int tpm_tis_i2c_send(struct tpm_chip *chip, u8 *buf, size_t len)
 522 {
 523         int rc, status;
 524         ssize_t burstcnt;
 525         size_t count = 0;
 526         u8 retries = 0;
 527         u8 sts = TPM_STS_GO;
 528
 529         if (len > TPM_BUFSIZE)
 530                 return -E2BIG;  /* command is too long for our tpm, sorry */
 531
 532         if (request_locality(chip, 0) < 0)
 533                 return -EBUSY;
 534
 535         status = tpm_tis_i2c_status(chip);
 536         if ((status & TPM_STS_COMMAND_READY) == 0) {
 537                 tpm_tis_i2c_ready(chip);
 538                 if (wait_for_stat
 539                     (chip, TPM_STS_COMMAND_READY,
 540                      chip->timeout_b, &status) < 0) {
 541                         rc = -ETIME;
 542                         goto out_err;
 543                 }
 544         }
 545
 546         while (count < len - 1) {
 547                 burstcnt = get_burstcount(chip);
 548
 549                 /* burstcnt < 0 = TPM is busy */
 550                 if (burstcnt < 0)
 551                         return burstcnt;
 552
 553                 if (burstcnt > (len - 1 - count))
 554                         burstcnt = len - 1 - count;
 555
 556                 rc = iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality),
 557                                    &(buf[count]), burstcnt);
 558                 if (rc == 0)
 559                         count += burstcnt;
 560                 else if (rc < 0)
 561                         retries++;
 562
 563                 /* avoid endless loop in case of broken HW */
 564                 if (retries > MAX_COUNT_LONG) {
 565                         rc = -EIO;
 566                         goto out_err;
 567                 }
 568
 569                 wait_for_stat(chip, TPM_STS_VALID,
 570                               chip->timeout_c, &status);
 571
 572                 if ((status & TPM_STS_DATA_EXPECT) == 0) {
 573                         rc = -EIO;
 574                         goto out_err;
 575                 }
 576         }
 577
 578         /* write last byte */
 579         iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality), &(buf[count]), 1);
 580         wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
 581         if ((status & TPM_STS_DATA_EXPECT) != 0) {
 582                 rc = -EIO;
 583                 goto out_err;
 584         }
 585
 586         /* go and do it */
 587         iic_tpm_write(TPM_STS(tpm_dev.locality), &sts, 1);
 588
 589         return len;
 590 out_err:
 591         tpm_tis_i2c_ready(chip);
 592         /* The TPM needs some time to clean up here,
 593          * so we sleep rather than keeping the bus busy
 594          */
 595         usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
 596         release_locality(chip, tpm_dev.locality, 0);
 597         return rc;
 598 }
 599
 600 static bool tpm_tis_i2c_req_canceled(struct tpm_chip *chip, u8 status)
 601 {
 602         return (status == TPM_STS_COMMAND_READY);
 603 }
 604
 605 static const struct tpm_class_ops tpm_tis_i2c = {
 606         .flags = TPM_OPS_AUTO_STARTUP,
 607         .status = tpm_tis_i2c_status,
 608         .recv = tpm_tis_i2c_recv,
 609         .send = tpm_tis_i2c_send,
 610         .cancel = tpm_tis_i2c_ready,
 611         .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 612         .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 613         .req_canceled = tpm_tis_i2c_req_canceled,
 614 };
 615
 616 static int tpm_tis_i2c_init(struct device *dev)
 617 {
 618         u32 vendor;
 619         int rc = 0;
 620         struct tpm_chip *chip;
 621
 622         chip = tpmm_chip_alloc(dev, &tpm_tis_i2c);
 623         if (IS_ERR(chip))
 624                 return PTR_ERR(chip);
 625
 626         /* Default timeouts */
 627         chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 628         chip->timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
 629         chip->timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 630         chip->timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 631
 632         if (request_locality(chip, 0) != 0) {
 633                 dev_err(dev, "could not request locality\n");
 634                 rc = -ENODEV;
 635                 goto out_err;
 636         }
 637
 638         /* read four bytes from DID_VID register */
 639         if (iic_tpm_read(TPM_DID_VID(0), (u8 *)&vendor, 4) < 0) {
 640                 dev_err(dev, "could not read vendor id\n");
 641                 rc = -EIO;
 642                 goto out_release;
 643         }
 644
 645         if (vendor == TPM_TIS_I2C_DID_VID_9645) {
 646                 tpm_dev.chip_type = SLB9645;
 647         } else if (vendor == TPM_TIS_I2C_DID_VID_9635) {
 648                 tpm_dev.chip_type = SLB9635;
 649         } else {
 650                 dev_err(dev, "vendor id did not match! ID was %08x\n", vendor);
 651                 rc = -ENODEV;
 652                 goto out_release;
 653         }
 654
 655         dev_info(dev, "1.2 TPM (device-id 0x%X)\n", vendor >> 16);
 656
 657         tpm_dev.chip = chip;
 658
 659         return tpm_chip_register(chip);
 660 out_release:
 661         release_locality(chip, tpm_dev.locality, 1);
 662         tpm_dev.client = NULL;
 663 out_err:
 664         return rc;
 665 }
 666
 667 static const struct i2c_device_id tpm_tis_i2c_table[] = {
 668         {"tpm_i2c_infineon"},
 669         {"slb9635tt"},
 670         {"slb9645tt"},
 671         {},
 672 };
 673
 674 MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_table);
 675
 676 #ifdef CONFIG_OF
 677 static const struct of_device_id tpm_tis_i2c_of_match[] = {
 678         {.compatible = "infineon,tpm_i2c_infineon"},
 679         {.compatible = "infineon,slb9635tt"},
 680         {.compatible = "infineon,slb9645tt"},
 681         {},
 682 };
 683 MODULE_DEVICE_TABLE(of, tpm_tis_i2c_of_match);
 684 #endif
 685
 686 static SIMPLE_DEV_PM_OPS(tpm_tis_i2c_ops, tpm_pm_suspend, tpm_pm_resume);
 687
 688 static int tpm_tis_i2c_probe(struct i2c_client *client,
 689                              const struct i2c_device_id *id)
 690 {
 691         int rc;
 692         struct device *dev = &(client->dev);
 693
 694         if (tpm_dev.client != NULL) {
 695                 dev_err(dev, "This driver only supports one client at a time\n");
 696                 return -EBUSY;  /* We only support one client */
 697         }
 698
 699         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 700                 dev_err(dev, "no algorithms associated to the i2c bus\n");
 701                 return -ENODEV;
 702         }
 703
 704         tpm_dev.client = client;
 705         rc = tpm_tis_i2c_init(&client->dev);
 706         if (rc != 0) {
 707                 tpm_dev.client = NULL;
 708                 rc = -ENODEV;
 709         }
 710         return rc;
 711 }
 712
 713 static int tpm_tis_i2c_remove(struct i2c_client *client)
 714 {
 715         struct tpm_chip *chip = tpm_dev.chip;
 716
 717         tpm_chip_unregister(chip);
 718         release_locality(chip, tpm_dev.locality, 1);
 719         tpm_dev.client = NULL;
 720
 721         return 0;
 722 }
 723
 724 static struct i2c_driver tpm_tis_i2c_driver = {
 725         .id_table = tpm_tis_i2c_table,
 726         .probe = tpm_tis_i2c_probe,
 727         .remove = tpm_tis_i2c_remove,
 728         .driver = {
 729                    .name = "tpm_i2c_infineon",
 730                    .pm = &tpm_tis_i2c_ops,
 731                    .of_match_table = of_match_ptr(tpm_tis_i2c_of_match),
 732                    },
 733 };
 734
 735 module_i2c_driver(tpm_tis_i2c_driver);
 736 MODULE_AUTHOR("Peter Huewe <peter.huewe@infineon.com>");
 737 MODULE_DESCRIPTION("TPM TIS I2C Infineon Driver");
 738 MODULE_VERSION("2.2.0");
 739 MODULE_LICENSE("GPL");