drivers/char/tpm/tpm_i2c_infineon.c

   1 /*
   2  * Copyright (C) 2012 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/init.h>
  25 #include <linux/i2c.h>
  26 #include <linux/module.h>
  27 #include <linux/moduleparam.h>
  28 #include <linux/wait.h>
  29 #include "tpm.h"
  30
  31 /* max. buffer size supported by our TPM */
  32 #define TPM_BUFSIZE 1260
  33
  34 /* max. number of iterations after I2C NAK */
  35 #define MAX_COUNT 3
  36
  37 #define SLEEP_DURATION_LOW 55
  38 #define SLEEP_DURATION_HI 65
  39
  40 /* max. number of iterations after I2C NAK for 'long' commands
  41  * we need this especially for sending TPM_READY, since the cleanup after the
  42  * transtion to the ready state may take some time, but it is unpredictable
  43  * how long it will take.
  44  */
  45 #define MAX_COUNT_LONG 50
  46
  47 #define SLEEP_DURATION_LONG_LOW 200
  48 #define SLEEP_DURATION_LONG_HI 220
  49
  50 /* After sending TPM_READY to 'reset' the TPM we have to sleep even longer */
  51 #define SLEEP_DURATION_RESET_LOW 2400
  52 #define SLEEP_DURATION_RESET_HI 2600
  53
  54 /* we want to use usleep_range instead of msleep for the 5ms TPM_TIMEOUT */
  55 #define TPM_TIMEOUT_US_LOW (TPM_TIMEOUT * 1000)
  56 #define TPM_TIMEOUT_US_HI  (TPM_TIMEOUT_US_LOW + 2000)
  57
  58 /* expected value for DIDVID register */
  59 #define TPM_TIS_I2C_DID_VID 0x000b15d1L
  60
  61 /* Structure to store I2C TPM specific stuff */
  62 struct tpm_inf_dev {
  63         struct i2c_client *client;
  64         u8 buf[TPM_BUFSIZE + sizeof(u8)]; /* max. buffer size + addr */
  65         struct tpm_chip *chip;
  66 };
  67
  68 static struct tpm_inf_dev tpm_dev;
  69 static struct i2c_driver tpm_tis_i2c_driver;
  70
  71 /*
  72  * iic_tpm_read() - read from TPM register
  73  * @addr: register address to read from
  74  * @buffer: provided by caller
  75  * @len: number of bytes to read
  76  *
  77  * Read len bytes from TPM register and put them into
  78  * buffer (little-endian format, i.e. first byte is put into buffer[0]).
  79  *
  80  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
  81  * values have to be swapped.
  82  *
  83  * NOTE: We can't unfortunately use the combined read/write functions
  84  * provided by the i2c core as the TPM currently does not support the
  85  * repeated start condition and due to it's special requirements.
  86  * The i2c_smbus* functions do not work for this chip.
  87  *
  88  * Return -EIO on error, 0 on success.
  89  */
  90 static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
  91 {
  92
  93         struct i2c_msg msg1 = { tpm_dev.client->addr, 0, 1, &addr };
  94         struct i2c_msg msg2 = { tpm_dev.client->addr, I2C_M_RD, len, buffer };
  95
  96         int rc;
  97         int count;
  98
  99         /* Lock the adapter for the duration of the whole sequence. */
 100         if (!tpm_dev.client->adapter->algo->master_xfer)
 101                 return -EOPNOTSUPP;
 102         i2c_lock_adapter(tpm_dev.client->adapter);
 103
 104         for (count = 0; count < MAX_COUNT; count++) {
 105                 rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
 106                 if (rc > 0)
 107                         break;  /* break here to skip sleep */
 108
 109                 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
 110         }
 111
 112         if (rc <= 0)
 113                 goto out;
 114
 115         /* After the TPM has successfully received the register address it needs
 116          * some time, thus we're sleeping here again, before retrieving the data
 117          */
 118         for (count = 0; count < MAX_COUNT; count++) {
 119                 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
 120                 rc = __i2c_transfer(tpm_dev.client->adapter, &msg2, 1);
 121                 if (rc > 0)
 122                         break;
 123
 124         }
 125
 126 out:
 127         i2c_unlock_adapter(tpm_dev.client->adapter);
 128         if (rc <= 0)
 129                 return -EIO;
 130
 131         return 0;
 132 }
 133
 134 static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
 135                                  unsigned int sleep_low,
 136                                  unsigned int sleep_hi, u8 max_count)
 137 {
 138         int rc = -EIO;
 139         int count;
 140
 141         struct i2c_msg msg1 = { tpm_dev.client->addr, 0, len + 1, tpm_dev.buf };
 142
 143         if (len > TPM_BUFSIZE)
 144                 return -EINVAL;
 145
 146         if (!tpm_dev.client->adapter->algo->master_xfer)
 147                 return -EOPNOTSUPP;
 148         i2c_lock_adapter(tpm_dev.client->adapter);
 149
 150         /* prepend the 'register address' to the buffer */
 151         tpm_dev.buf[0] = addr;
 152         memcpy(&(tpm_dev.buf[1]), buffer, len);
 153
 154         /*
 155          * NOTE: We have to use these special mechanisms here and unfortunately
 156          * cannot rely on the standard behavior of i2c_transfer.
 157          */
 158         for (count = 0; count < max_count; count++) {
 159                 rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
 160                 if (rc > 0)
 161                         break;
 162
 163                 usleep_range(sleep_low, sleep_hi);
 164         }
 165
 166         i2c_unlock_adapter(tpm_dev.client->adapter);
 167         if (rc <= 0)
 168                 return -EIO;
 169
 170         return 0;
 171 }
 172
 173 /*
 174  * iic_tpm_write() - write to TPM register
 175  * @addr: register address to write to
 176  * @buffer: containing data to be written
 177  * @len: number of bytes to write
 178  *
 179  * Write len bytes from provided buffer to TPM register (little
 180  * endian format, i.e. buffer[0] is written as first byte).
 181  *
 182  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
 183  * values have to be swapped.
 184  *
 185  * NOTE: use this function instead of the iic_tpm_write_generic function.
 186  *
 187  * Return -EIO on error, 0 on success
 188  */
 189 static int iic_tpm_write(u8 addr, u8 *buffer, size_t len)
 190 {
 191         return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LOW,
 192                                      SLEEP_DURATION_HI, MAX_COUNT);
 193 }
 194
 195 /*
 196  * This function is needed especially for the cleanup situation after
 197  * sending TPM_READY
 198  * */
 199 static int iic_tpm_write_long(u8 addr, u8 *buffer, size_t len)
 200 {
 201         return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LONG_LOW,
 202                                      SLEEP_DURATION_LONG_HI, MAX_COUNT_LONG);
 203 }
 204
 205 enum tis_access {
 206         TPM_ACCESS_VALID = 0x80,
 207         TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
 208         TPM_ACCESS_REQUEST_PENDING = 0x04,
 209         TPM_ACCESS_REQUEST_USE = 0x02,
 210 };
 211
 212 enum tis_status {
 213         TPM_STS_VALID = 0x80,
 214         TPM_STS_COMMAND_READY = 0x40,
 215         TPM_STS_GO = 0x20,
 216         TPM_STS_DATA_AVAIL = 0x10,
 217         TPM_STS_DATA_EXPECT = 0x08,
 218 };
 219
 220 enum tis_defaults {
 221         TIS_SHORT_TIMEOUT = 750,        /* ms */
 222         TIS_LONG_TIMEOUT = 2000,        /* 2 sec */
 223 };
 224
 225 #define TPM_ACCESS(l)                   (0x0000 | ((l) << 4))
 226 #define TPM_STS(l)                      (0x0001 | ((l) << 4))
 227 #define TPM_DATA_FIFO(l)                (0x0005 | ((l) << 4))
 228 #define TPM_DID_VID(l)                  (0x0006 | ((l) << 4))
 229
 230 static int check_locality(struct tpm_chip *chip, int loc)
 231 {
 232         u8 buf;
 233         int rc;
 234
 235         rc = iic_tpm_read(TPM_ACCESS(loc), &buf, 1);
 236         if (rc < 0)
 237                 return rc;
 238
 239         if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
 240             (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
 241                 chip->vendor.locality = loc;
 242                 return loc;
 243         }
 244
 245         return -EIO;
 246 }
 247
 248 /* implementation similar to tpm_tis */
 249 static void release_locality(struct tpm_chip *chip, int loc, int force)
 250 {
 251         u8 buf;
 252         if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0)
 253                 return;
 254
 255         if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
 256             (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) {
 257                 buf = TPM_ACCESS_ACTIVE_LOCALITY;
 258                 iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
 259         }
 260 }
 261
 262 static int request_locality(struct tpm_chip *chip, int loc)
 263 {
 264         unsigned long stop;
 265         u8 buf = TPM_ACCESS_REQUEST_USE;
 266
 267         if (check_locality(chip, loc) >= 0)
 268                 return loc;
 269
 270         iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
 271
 272         /* wait for burstcount */
 273         stop = jiffies + chip->vendor.timeout_a;
 274         do {
 275                 if (check_locality(chip, loc) >= 0)
 276                         return loc;
 277                 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
 278         } while (time_before(jiffies, stop));
 279
 280         return -ETIME;
 281 }
 282
 283 static u8 tpm_tis_i2c_status(struct tpm_chip *chip)
 284 {
 285         /* NOTE: since I2C read may fail, return 0 in this case --> time-out */
 286         u8 buf;
 287         if (iic_tpm_read(TPM_STS(chip->vendor.locality), &buf, 1) < 0)
 288                 return 0;
 289         else
 290                 return buf;
 291 }
 292
 293 static void tpm_tis_i2c_ready(struct tpm_chip *chip)
 294 {
 295         /* this causes the current command to be aborted */
 296         u8 buf = TPM_STS_COMMAND_READY;
 297         iic_tpm_write_long(TPM_STS(chip->vendor.locality), &buf, 1);
 298 }
 299
 300 static ssize_t get_burstcount(struct tpm_chip *chip)
 301 {
 302         unsigned long stop;
 303         ssize_t burstcnt;
 304         u8 buf[3];
 305
 306         /* wait for burstcount */
 307         /* which timeout value, spec has 2 answers (c & d) */
 308         stop = jiffies + chip->vendor.timeout_d;
 309         do {
 310                 /* Note: STS is little endian */
 311                 if (iic_tpm_read(TPM_STS(chip->vendor.locality)+1, buf, 3) < 0)
 312                         burstcnt = 0;
 313                 else
 314                         burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0];
 315
 316                 if (burstcnt)
 317                         return burstcnt;
 318
 319                 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
 320         } while (time_before(jiffies, stop));
 321         return -EBUSY;
 322 }
 323
 324 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
 325                          int *status)
 326 {
 327         unsigned long stop;
 328
 329         /* check current status */
 330         *status = tpm_tis_i2c_status(chip);
 331         if ((*status & mask) == mask)
 332                 return 0;
 333
 334         stop = jiffies + timeout;
 335         do {
 336                 /* since we just checked the status, give the TPM some time */
 337                 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
 338                 *status = tpm_tis_i2c_status(chip);
 339                 if ((*status & mask) == mask)
 340                         return 0;
 341
 342         } while (time_before(jiffies, stop));
 343
 344         return -ETIME;
 345 }
 346
 347 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
 348 {
 349         size_t size = 0;
 350         ssize_t burstcnt;
 351         u8 retries = 0;
 352         int rc;
 353
 354         while (size < count) {
 355                 burstcnt = get_burstcount(chip);
 356
 357                 /* burstcnt < 0 = TPM is busy */
 358                 if (burstcnt < 0)
 359                         return burstcnt;
 360
 361                 /* limit received data to max. left */
 362                 if (burstcnt > (count - size))
 363                         burstcnt = count - size;
 364
 365                 rc = iic_tpm_read(TPM_DATA_FIFO(chip->vendor.locality),
 366                                   &(buf[size]), burstcnt);
 367                 if (rc == 0)
 368                         size += burstcnt;
 369                 else if (rc < 0)
 370                         retries++;
 371
 372                 /* avoid endless loop in case of broken HW */
 373                 if (retries > MAX_COUNT_LONG)
 374                         return -EIO;
 375
 376         }
 377         return size;
 378 }
 379
 380 static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 381 {
 382         int size = 0;
 383         int expected, status;
 384
 385         if (count < TPM_HEADER_SIZE) {
 386                 size = -EIO;
 387                 goto out;
 388         }
 389
 390         /* read first 10 bytes, including tag, paramsize, and result */
 391         size = recv_data(chip, buf, TPM_HEADER_SIZE);
 392         if (size < TPM_HEADER_SIZE) {
 393                 dev_err(chip->dev, "Unable to read header\n");
 394                 goto out;
 395         }
 396
 397         expected = be32_to_cpu(*(__be32 *)(buf + 2));
 398         if ((size_t) expected > count) {
 399                 size = -EIO;
 400                 goto out;
 401         }
 402
 403         size += recv_data(chip, &buf[TPM_HEADER_SIZE],
 404                           expected - TPM_HEADER_SIZE);
 405         if (size < expected) {
 406                 dev_err(chip->dev, "Unable to read remainder of result\n");
 407                 size = -ETIME;
 408                 goto out;
 409         }
 410
 411         wait_for_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c, &status);
 412         if (status & TPM_STS_DATA_AVAIL) {      /* retry? */
 413                 dev_err(chip->dev, "Error left over data\n");
 414                 size = -EIO;
 415                 goto out;
 416         }
 417
 418 out:
 419         tpm_tis_i2c_ready(chip);
 420         /* The TPM needs some time to clean up here,
 421          * so we sleep rather than keeping the bus busy
 422          */
 423         usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
 424         release_locality(chip, chip->vendor.locality, 0);
 425         return size;
 426 }
 427
 428 static int tpm_tis_i2c_send(struct tpm_chip *chip, u8 *buf, size_t len)
 429 {
 430         int rc, status;
 431         ssize_t burstcnt;
 432         size_t count = 0;
 433         u8 retries = 0;
 434         u8 sts = TPM_STS_GO;
 435
 436         if (len > TPM_BUFSIZE)
 437                 return -E2BIG;  /* command is too long for our tpm, sorry */
 438
 439         if (request_locality(chip, 0) < 0)
 440                 return -EBUSY;
 441
 442         status = tpm_tis_i2c_status(chip);
 443         if ((status & TPM_STS_COMMAND_READY) == 0) {
 444                 tpm_tis_i2c_ready(chip);
 445                 if (wait_for_stat
 446                     (chip, TPM_STS_COMMAND_READY,
 447                      chip->vendor.timeout_b, &status) < 0) {
 448                         rc = -ETIME;
 449                         goto out_err;
 450                 }
 451         }
 452
 453         while (count < len - 1) {
 454                 burstcnt = get_burstcount(chip);
 455
 456                 /* burstcnt < 0 = TPM is busy */
 457                 if (burstcnt < 0)
 458                         return burstcnt;
 459
 460                 if (burstcnt > (len - 1 - count))
 461                         burstcnt = len - 1 - count;
 462
 463                 rc = iic_tpm_write(TPM_DATA_FIFO(chip->vendor.locality),
 464                                    &(buf[count]), burstcnt);
 465                 if (rc == 0)
 466                         count += burstcnt;
 467                 else if (rc < 0)
 468                         retries++;
 469
 470                 /* avoid endless loop in case of broken HW */
 471                 if (retries > MAX_COUNT_LONG) {
 472                         rc = -EIO;
 473                         goto out_err;
 474                 }
 475
 476                 wait_for_stat(chip, TPM_STS_VALID,
 477                               chip->vendor.timeout_c, &status);
 478
 479                 if ((status & TPM_STS_DATA_EXPECT) == 0) {
 480                         rc = -EIO;
 481                         goto out_err;
 482                 }
 483
 484         }
 485
 486         /* write last byte */
 487         iic_tpm_write(TPM_DATA_FIFO(chip->vendor.locality), &(buf[count]), 1);
 488         wait_for_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c, &status);
 489         if ((status & TPM_STS_DATA_EXPECT) != 0) {
 490                 rc = -EIO;
 491                 goto out_err;
 492         }
 493
 494         /* go and do it */
 495         iic_tpm_write(TPM_STS(chip->vendor.locality), &sts, 1);
 496
 497         return len;
 498 out_err:
 499         tpm_tis_i2c_ready(chip);
 500         /* The TPM needs some time to clean up here,
 501          * so we sleep rather than keeping the bus busy
 502          */
 503         usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
 504         release_locality(chip, chip->vendor.locality, 0);
 505         return rc;
 506 }
 507
 508 static bool tpm_tis_i2c_req_canceled(struct tpm_chip *chip, u8 status)
 509 {
 510         return (status == TPM_STS_COMMAND_READY);
 511 }
 512
 513 static const struct file_operations tis_ops = {
 514         .owner = THIS_MODULE,
 515         .llseek = no_llseek,
 516         .open = tpm_open,
 517         .read = tpm_read,
 518         .write = tpm_write,
 519         .release = tpm_release,
 520 };
 521
 522 static DEVICE_ATTR(pubek, S_IRUGO, tpm_show_pubek, NULL);
 523 static DEVICE_ATTR(pcrs, S_IRUGO, tpm_show_pcrs, NULL);
 524 static DEVICE_ATTR(enabled, S_IRUGO, tpm_show_enabled, NULL);
 525 static DEVICE_ATTR(active, S_IRUGO, tpm_show_active, NULL);
 526 static DEVICE_ATTR(owned, S_IRUGO, tpm_show_owned, NULL);
 527 static DEVICE_ATTR(temp_deactivated, S_IRUGO, tpm_show_temp_deactivated, NULL);
 528 static DEVICE_ATTR(caps, S_IRUGO, tpm_show_caps_1_2, NULL);
 529 static DEVICE_ATTR(cancel, S_IWUSR | S_IWGRP, NULL, tpm_store_cancel);
 530 static DEVICE_ATTR(durations, S_IRUGO, tpm_show_durations, NULL);
 531 static DEVICE_ATTR(timeouts, S_IRUGO, tpm_show_timeouts, NULL);
 532
 533 static struct attribute *tis_attrs[] = {
 534         &dev_attr_pubek.attr,
 535         &dev_attr_pcrs.attr,
 536         &dev_attr_enabled.attr,
 537         &dev_attr_active.attr,
 538         &dev_attr_owned.attr,
 539         &dev_attr_temp_deactivated.attr,
 540         &dev_attr_caps.attr,
 541         &dev_attr_cancel.attr,
 542         &dev_attr_durations.attr,
 543         &dev_attr_timeouts.attr,
 544         NULL,
 545 };
 546
 547 static struct attribute_group tis_attr_grp = {
 548         .attrs = tis_attrs
 549 };
 550
 551 static struct tpm_vendor_specific tpm_tis_i2c = {
 552         .status = tpm_tis_i2c_status,
 553         .recv = tpm_tis_i2c_recv,
 554         .send = tpm_tis_i2c_send,
 555         .cancel = tpm_tis_i2c_ready,
 556         .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 557         .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 558         .req_canceled = tpm_tis_i2c_req_canceled,
 559         .attr_group = &tis_attr_grp,
 560         .miscdev.fops = &tis_ops,
 561 };
 562
 563 static int tpm_tis_i2c_init(struct device *dev)
 564 {
 565         u32 vendor;
 566         int rc = 0;
 567         struct tpm_chip *chip;
 568
 569         chip = tpm_register_hardware(dev, &tpm_tis_i2c);
 570         if (!chip) {
 571                 rc = -ENODEV;
 572                 goto out_err;
 573         }
 574
 575         /* Disable interrupts */
 576         chip->vendor.irq = 0;
 577
 578         /* Default timeouts */
 579         chip->vendor.timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 580         chip->vendor.timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
 581         chip->vendor.timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 582         chip->vendor.timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 583
 584         if (request_locality(chip, 0) != 0) {
 585                 rc = -ENODEV;
 586                 goto out_vendor;
 587         }
 588
 589         /* read four bytes from DID_VID register */
 590         if (iic_tpm_read(TPM_DID_VID(0), (u8 *)&vendor, 4) < 0) {
 591                 rc = -EIO;
 592                 goto out_release;
 593         }
 594
 595         /* create DID_VID register value, after swapping to little-endian */
 596         vendor = be32_to_cpu((__be32) vendor);
 597
 598         if (vendor != TPM_TIS_I2C_DID_VID) {
 599                 rc = -ENODEV;
 600                 goto out_release;
 601         }
 602
 603         dev_info(dev, "1.2 TPM (device-id 0x%X)\n", vendor >> 16);
 604
 605         INIT_LIST_HEAD(&chip->vendor.list);
 606         tpm_dev.chip = chip;
 607
 608         tpm_get_timeouts(chip);
 609         tpm_do_selftest(chip);
 610
 611         return 0;
 612
 613 out_release:
 614         release_locality(chip, chip->vendor.locality, 1);
 615
 616 out_vendor:
 617         /* close file handles */
 618         tpm_dev_vendor_release(chip);
 619
 620         /* remove hardware */
 621         tpm_remove_hardware(chip->dev);
 622
 623         /* reset these pointers, otherwise we oops */
 624         chip->dev->release = NULL;
 625         chip->release = NULL;
 626         tpm_dev.client = NULL;
 627         dev_set_drvdata(chip->dev, chip);
 628 out_err:
 629         return rc;
 630 }
 631
 632 static const struct i2c_device_id tpm_tis_i2c_table[] = {
 633         {"tpm_i2c_infineon", 0},
 634         {},
 635 };
 636
 637 MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_table);
 638 static SIMPLE_DEV_PM_OPS(tpm_tis_i2c_ops, tpm_pm_suspend, tpm_pm_resume);
 639
 640 static int tpm_tis_i2c_probe(struct i2c_client *client,
 641                              const struct i2c_device_id *id)
 642 {
 643         int rc;
 644         if (tpm_dev.client != NULL)
 645                 return -EBUSY;  /* We only support one client */
 646
 647         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 648                 dev_err(&client->dev,
 649                         "no algorithms associated to the i2c bus\n");
 650                 return -ENODEV;
 651         }
 652
 653         client->driver = &tpm_tis_i2c_driver;
 654         tpm_dev.client = client;
 655         rc = tpm_tis_i2c_init(&client->dev);
 656         if (rc != 0) {
 657                 client->driver = NULL;
 658                 tpm_dev.client = NULL;
 659                 rc = -ENODEV;
 660         }
 661         return rc;
 662 }
 663
 664 static int tpm_tis_i2c_remove(struct i2c_client *client)
 665 {
 666         struct tpm_chip *chip = tpm_dev.chip;
 667         release_locality(chip, chip->vendor.locality, 1);
 668
 669         /* close file handles */
 670         tpm_dev_vendor_release(chip);
 671
 672         /* remove hardware */
 673         tpm_remove_hardware(chip->dev);
 674
 675         /* reset these pointers, otherwise we oops */
 676         chip->dev->release = NULL;
 677         chip->release = NULL;
 678         tpm_dev.client = NULL;
 679         dev_set_drvdata(chip->dev, chip);
 680
 681         return 0;
 682 }
 683
 684 static struct i2c_driver tpm_tis_i2c_driver = {
 685
 686         .id_table = tpm_tis_i2c_table,
 687         .probe = tpm_tis_i2c_probe,
 688         .remove = tpm_tis_i2c_remove,
 689         .driver = {
 690                    .name = "tpm_i2c_infineon",
 691                    .owner = THIS_MODULE,
 692                    .pm = &tpm_tis_i2c_ops,
 693                    },
 694 };
 695
 696 module_i2c_driver(tpm_tis_i2c_driver);
 697 MODULE_AUTHOR("Peter Huewe <peter.huewe@infineon.com>");
 698 MODULE_DESCRIPTION("TPM TIS I2C Infineon Driver");
 699 MODULE_VERSION("2.1.5");
 700 MODULE_LICENSE("GPL");