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 = {
  94                 .addr = tpm_dev.client->addr,
  95                 .len = 1,
  96                 .buf = &addr
  97         };
  98         struct i2c_msg msg2 = {
  99                 .addr = tpm_dev.client->addr,
 100                 .flags = I2C_M_RD,
 101                 .len = len,
 102                 .buf = buffer
 103         };
 104
 105         int rc;
 106         int count;
 107
 108         /* Lock the adapter for the duration of the whole sequence. */
 109         if (!tpm_dev.client->adapter->algo->master_xfer)
 110                 return -EOPNOTSUPP;
 111         i2c_lock_adapter(tpm_dev.client->adapter);
 112
 113         for (count = 0; count < MAX_COUNT; count++) {
 114                 rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
 115                 if (rc > 0)
 116                         break;  /* break here to skip sleep */
 117
 118                 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
 119         }
 120
 121         if (rc <= 0)
 122                 goto out;
 123
 124         /* After the TPM has successfully received the register address it needs
 125          * some time, thus we're sleeping here again, before retrieving the data
 126          */
 127         for (count = 0; count < MAX_COUNT; count++) {
 128                 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
 129                 rc = __i2c_transfer(tpm_dev.client->adapter, &msg2, 1);
 130                 if (rc > 0)
 131                         break;
 132
 133         }
 134
 135 out:
 136         i2c_unlock_adapter(tpm_dev.client->adapter);
 137         if (rc <= 0)
 138                 return -EIO;
 139
 140         return 0;
 141 }
 142
 143 static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
 144                                  unsigned int sleep_low,
 145                                  unsigned int sleep_hi, u8 max_count)
 146 {
 147         int rc = -EIO;
 148         int count;
 149
 150         struct i2c_msg msg1 = {
 151                 .addr = tpm_dev.client->addr,
 152                 .len = len + 1,
 153                 .buf = tpm_dev.buf
 154         };
 155
 156         if (len > TPM_BUFSIZE)
 157                 return -EINVAL;
 158
 159         if (!tpm_dev.client->adapter->algo->master_xfer)
 160                 return -EOPNOTSUPP;
 161         i2c_lock_adapter(tpm_dev.client->adapter);
 162
 163         /* prepend the 'register address' to the buffer */
 164         tpm_dev.buf[0] = addr;
 165         memcpy(&(tpm_dev.buf[1]), buffer, len);
 166
 167         /*
 168          * NOTE: We have to use these special mechanisms here and unfortunately
 169          * cannot rely on the standard behavior of i2c_transfer.
 170          */
 171         for (count = 0; count < max_count; count++) {
 172                 rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
 173                 if (rc > 0)
 174                         break;
 175
 176                 usleep_range(sleep_low, sleep_hi);
 177         }
 178
 179         i2c_unlock_adapter(tpm_dev.client->adapter);
 180         if (rc <= 0)
 181                 return -EIO;
 182
 183         return 0;
 184 }
 185
 186 /*
 187  * iic_tpm_write() - write to TPM register
 188  * @addr: register address to write to
 189  * @buffer: containing data to be written
 190  * @len: number of bytes to write
 191  *
 192  * Write len bytes from provided buffer to TPM register (little
 193  * endian format, i.e. buffer[0] is written as first byte).
 194  *
 195  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
 196  * values have to be swapped.
 197  *
 198  * NOTE: use this function instead of the iic_tpm_write_generic function.
 199  *
 200  * Return -EIO on error, 0 on success
 201  */
 202 static int iic_tpm_write(u8 addr, u8 *buffer, size_t len)
 203 {
 204         return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LOW,
 205                                      SLEEP_DURATION_HI, MAX_COUNT);
 206 }
 207
 208 /*
 209  * This function is needed especially for the cleanup situation after
 210  * sending TPM_READY
 211  * */
 212 static int iic_tpm_write_long(u8 addr, u8 *buffer, size_t len)
 213 {
 214         return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LONG_LOW,
 215                                      SLEEP_DURATION_LONG_HI, MAX_COUNT_LONG);
 216 }
 217
 218 enum tis_access {
 219         TPM_ACCESS_VALID = 0x80,
 220         TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
 221         TPM_ACCESS_REQUEST_PENDING = 0x04,
 222         TPM_ACCESS_REQUEST_USE = 0x02,
 223 };
 224
 225 enum tis_status {
 226         TPM_STS_VALID = 0x80,
 227         TPM_STS_COMMAND_READY = 0x40,
 228         TPM_STS_GO = 0x20,
 229         TPM_STS_DATA_AVAIL = 0x10,
 230         TPM_STS_DATA_EXPECT = 0x08,
 231 };
 232
 233 enum tis_defaults {
 234         TIS_SHORT_TIMEOUT = 750,        /* ms */
 235         TIS_LONG_TIMEOUT = 2000,        /* 2 sec */
 236 };
 237
 238 #define TPM_ACCESS(l)                   (0x0000 | ((l) << 4))
 239 #define TPM_STS(l)                      (0x0001 | ((l) << 4))
 240 #define TPM_DATA_FIFO(l)                (0x0005 | ((l) << 4))
 241 #define TPM_DID_VID(l)                  (0x0006 | ((l) << 4))
 242
 243 static int check_locality(struct tpm_chip *chip, int loc)
 244 {
 245         u8 buf;
 246         int rc;
 247
 248         rc = iic_tpm_read(TPM_ACCESS(loc), &buf, 1);
 249         if (rc < 0)
 250                 return rc;
 251
 252         if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
 253             (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
 254                 chip->vendor.locality = loc;
 255                 return loc;
 256         }
 257
 258         return -EIO;
 259 }
 260
 261 /* implementation similar to tpm_tis */
 262 static void release_locality(struct tpm_chip *chip, int loc, int force)
 263 {
 264         u8 buf;
 265         if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0)
 266                 return;
 267
 268         if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
 269             (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) {
 270                 buf = TPM_ACCESS_ACTIVE_LOCALITY;
 271                 iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
 272         }
 273 }
 274
 275 static int request_locality(struct tpm_chip *chip, int loc)
 276 {
 277         unsigned long stop;
 278         u8 buf = TPM_ACCESS_REQUEST_USE;
 279
 280         if (check_locality(chip, loc) >= 0)
 281                 return loc;
 282
 283         iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
 284
 285         /* wait for burstcount */
 286         stop = jiffies + chip->vendor.timeout_a;
 287         do {
 288                 if (check_locality(chip, loc) >= 0)
 289                         return loc;
 290                 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
 291         } while (time_before(jiffies, stop));
 292
 293         return -ETIME;
 294 }
 295
 296 static u8 tpm_tis_i2c_status(struct tpm_chip *chip)
 297 {
 298         /* NOTE: since I2C read may fail, return 0 in this case --> time-out */
 299         u8 buf;
 300         if (iic_tpm_read(TPM_STS(chip->vendor.locality), &buf, 1) < 0)
 301                 return 0;
 302         else
 303                 return buf;
 304 }
 305
 306 static void tpm_tis_i2c_ready(struct tpm_chip *chip)
 307 {
 308         /* this causes the current command to be aborted */
 309         u8 buf = TPM_STS_COMMAND_READY;
 310         iic_tpm_write_long(TPM_STS(chip->vendor.locality), &buf, 1);
 311 }
 312
 313 static ssize_t get_burstcount(struct tpm_chip *chip)
 314 {
 315         unsigned long stop;
 316         ssize_t burstcnt;
 317         u8 buf[3];
 318
 319         /* wait for burstcount */
 320         /* which timeout value, spec has 2 answers (c & d) */
 321         stop = jiffies + chip->vendor.timeout_d;
 322         do {
 323                 /* Note: STS is little endian */
 324                 if (iic_tpm_read(TPM_STS(chip->vendor.locality)+1, buf, 3) < 0)
 325                         burstcnt = 0;
 326                 else
 327                         burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0];
 328
 329                 if (burstcnt)
 330                         return burstcnt;
 331
 332                 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
 333         } while (time_before(jiffies, stop));
 334         return -EBUSY;
 335 }
 336
 337 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
 338                          int *status)
 339 {
 340         unsigned long stop;
 341
 342         /* check current status */
 343         *status = tpm_tis_i2c_status(chip);
 344         if ((*status & mask) == mask)
 345                 return 0;
 346
 347         stop = jiffies + timeout;
 348         do {
 349                 /* since we just checked the status, give the TPM some time */
 350                 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
 351                 *status = tpm_tis_i2c_status(chip);
 352                 if ((*status & mask) == mask)
 353                         return 0;
 354
 355         } while (time_before(jiffies, stop));
 356
 357         return -ETIME;
 358 }
 359
 360 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
 361 {
 362         size_t size = 0;
 363         ssize_t burstcnt;
 364         u8 retries = 0;
 365         int rc;
 366
 367         while (size < count) {
 368                 burstcnt = get_burstcount(chip);
 369
 370                 /* burstcnt < 0 = TPM is busy */
 371                 if (burstcnt < 0)
 372                         return burstcnt;
 373
 374                 /* limit received data to max. left */
 375                 if (burstcnt > (count - size))
 376                         burstcnt = count - size;
 377
 378                 rc = iic_tpm_read(TPM_DATA_FIFO(chip->vendor.locality),
 379                                   &(buf[size]), burstcnt);
 380                 if (rc == 0)
 381                         size += burstcnt;
 382                 else if (rc < 0)
 383                         retries++;
 384
 385                 /* avoid endless loop in case of broken HW */
 386                 if (retries > MAX_COUNT_LONG)
 387                         return -EIO;
 388
 389         }
 390         return size;
 391 }
 392
 393 static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 394 {
 395         int size = 0;
 396         int expected, status;
 397
 398         if (count < TPM_HEADER_SIZE) {
 399                 size = -EIO;
 400                 goto out;
 401         }
 402
 403         /* read first 10 bytes, including tag, paramsize, and result */
 404         size = recv_data(chip, buf, TPM_HEADER_SIZE);
 405         if (size < TPM_HEADER_SIZE) {
 406                 dev_err(chip->dev, "Unable to read header\n");
 407                 goto out;
 408         }
 409
 410         expected = be32_to_cpu(*(__be32 *)(buf + 2));
 411         if ((size_t) expected > count) {
 412                 size = -EIO;
 413                 goto out;
 414         }
 415
 416         size += recv_data(chip, &buf[TPM_HEADER_SIZE],
 417                           expected - TPM_HEADER_SIZE);
 418         if (size < expected) {
 419                 dev_err(chip->dev, "Unable to read remainder of result\n");
 420                 size = -ETIME;
 421                 goto out;
 422         }
 423
 424         wait_for_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c, &status);
 425         if (status & TPM_STS_DATA_AVAIL) {      /* retry? */
 426                 dev_err(chip->dev, "Error left over data\n");
 427                 size = -EIO;
 428                 goto out;
 429         }
 430
 431 out:
 432         tpm_tis_i2c_ready(chip);
 433         /* The TPM needs some time to clean up here,
 434          * so we sleep rather than keeping the bus busy
 435          */
 436         usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
 437         release_locality(chip, chip->vendor.locality, 0);
 438         return size;
 439 }
 440
 441 static int tpm_tis_i2c_send(struct tpm_chip *chip, u8 *buf, size_t len)
 442 {
 443         int rc, status;
 444         ssize_t burstcnt;
 445         size_t count = 0;
 446         u8 retries = 0;
 447         u8 sts = TPM_STS_GO;
 448
 449         if (len > TPM_BUFSIZE)
 450                 return -E2BIG;  /* command is too long for our tpm, sorry */
 451
 452         if (request_locality(chip, 0) < 0)
 453                 return -EBUSY;
 454
 455         status = tpm_tis_i2c_status(chip);
 456         if ((status & TPM_STS_COMMAND_READY) == 0) {
 457                 tpm_tis_i2c_ready(chip);
 458                 if (wait_for_stat
 459                     (chip, TPM_STS_COMMAND_READY,
 460                      chip->vendor.timeout_b, &status) < 0) {
 461                         rc = -ETIME;
 462                         goto out_err;
 463                 }
 464         }
 465
 466         while (count < len - 1) {
 467                 burstcnt = get_burstcount(chip);
 468
 469                 /* burstcnt < 0 = TPM is busy */
 470                 if (burstcnt < 0)
 471                         return burstcnt;
 472
 473                 if (burstcnt > (len - 1 - count))
 474                         burstcnt = len - 1 - count;
 475
 476                 rc = iic_tpm_write(TPM_DATA_FIFO(chip->vendor.locality),
 477                                    &(buf[count]), burstcnt);
 478                 if (rc == 0)
 479                         count += burstcnt;
 480                 else if (rc < 0)
 481                         retries++;
 482
 483                 /* avoid endless loop in case of broken HW */
 484                 if (retries > MAX_COUNT_LONG) {
 485                         rc = -EIO;
 486                         goto out_err;
 487                 }
 488
 489                 wait_for_stat(chip, TPM_STS_VALID,
 490                               chip->vendor.timeout_c, &status);
 491
 492                 if ((status & TPM_STS_DATA_EXPECT) == 0) {
 493                         rc = -EIO;
 494                         goto out_err;
 495                 }
 496
 497         }
 498
 499         /* write last byte */
 500         iic_tpm_write(TPM_DATA_FIFO(chip->vendor.locality), &(buf[count]), 1);
 501         wait_for_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c, &status);
 502         if ((status & TPM_STS_DATA_EXPECT) != 0) {
 503                 rc = -EIO;
 504                 goto out_err;
 505         }
 506
 507         /* go and do it */
 508         iic_tpm_write(TPM_STS(chip->vendor.locality), &sts, 1);
 509
 510         return len;
 511 out_err:
 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, chip->vendor.locality, 0);
 518         return rc;
 519 }
 520
 521 static bool tpm_tis_i2c_req_canceled(struct tpm_chip *chip, u8 status)
 522 {
 523         return (status == TPM_STS_COMMAND_READY);
 524 }
 525
 526 static const struct file_operations tis_ops = {
 527         .owner = THIS_MODULE,
 528         .llseek = no_llseek,
 529         .open = tpm_open,
 530         .read = tpm_read,
 531         .write = tpm_write,
 532         .release = tpm_release,
 533 };
 534
 535 static DEVICE_ATTR(pubek, S_IRUGO, tpm_show_pubek, NULL);
 536 static DEVICE_ATTR(pcrs, S_IRUGO, tpm_show_pcrs, NULL);
 537 static DEVICE_ATTR(enabled, S_IRUGO, tpm_show_enabled, NULL);
 538 static DEVICE_ATTR(active, S_IRUGO, tpm_show_active, NULL);
 539 static DEVICE_ATTR(owned, S_IRUGO, tpm_show_owned, NULL);
 540 static DEVICE_ATTR(temp_deactivated, S_IRUGO, tpm_show_temp_deactivated, NULL);
 541 static DEVICE_ATTR(caps, S_IRUGO, tpm_show_caps_1_2, NULL);
 542 static DEVICE_ATTR(cancel, S_IWUSR | S_IWGRP, NULL, tpm_store_cancel);
 543 static DEVICE_ATTR(durations, S_IRUGO, tpm_show_durations, NULL);
 544 static DEVICE_ATTR(timeouts, S_IRUGO, tpm_show_timeouts, NULL);
 545
 546 static struct attribute *tis_attrs[] = {
 547         &dev_attr_pubek.attr,
 548         &dev_attr_pcrs.attr,
 549         &dev_attr_enabled.attr,
 550         &dev_attr_active.attr,
 551         &dev_attr_owned.attr,
 552         &dev_attr_temp_deactivated.attr,
 553         &dev_attr_caps.attr,
 554         &dev_attr_cancel.attr,
 555         &dev_attr_durations.attr,
 556         &dev_attr_timeouts.attr,
 557         NULL,
 558 };
 559
 560 static struct attribute_group tis_attr_grp = {
 561         .attrs = tis_attrs
 562 };
 563
 564 static struct tpm_vendor_specific tpm_tis_i2c = {
 565         .status = tpm_tis_i2c_status,
 566         .recv = tpm_tis_i2c_recv,
 567         .send = tpm_tis_i2c_send,
 568         .cancel = tpm_tis_i2c_ready,
 569         .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 570         .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 571         .req_canceled = tpm_tis_i2c_req_canceled,
 572         .attr_group = &tis_attr_grp,
 573         .miscdev.fops = &tis_ops,
 574 };
 575
 576 static int tpm_tis_i2c_init(struct device *dev)
 577 {
 578         u32 vendor;
 579         int rc = 0;
 580         struct tpm_chip *chip;
 581
 582         chip = tpm_register_hardware(dev, &tpm_tis_i2c);
 583         if (!chip) {
 584                 rc = -ENODEV;
 585                 goto out_err;
 586         }
 587
 588         /* Disable interrupts */
 589         chip->vendor.irq = 0;
 590
 591         /* Default timeouts */
 592         chip->vendor.timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 593         chip->vendor.timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
 594         chip->vendor.timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 595         chip->vendor.timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 596
 597         if (request_locality(chip, 0) != 0) {
 598                 rc = -ENODEV;
 599                 goto out_vendor;
 600         }
 601
 602         /* read four bytes from DID_VID register */
 603         if (iic_tpm_read(TPM_DID_VID(0), (u8 *)&vendor, 4) < 0) {
 604                 rc = -EIO;
 605                 goto out_release;
 606         }
 607
 608         /* create DID_VID register value, after swapping to little-endian */
 609         vendor = be32_to_cpu((__be32) vendor);
 610
 611         if (vendor != TPM_TIS_I2C_DID_VID) {
 612                 rc = -ENODEV;
 613                 goto out_release;
 614         }
 615
 616         dev_info(dev, "1.2 TPM (device-id 0x%X)\n", vendor >> 16);
 617
 618         INIT_LIST_HEAD(&chip->vendor.list);
 619         tpm_dev.chip = chip;
 620
 621         tpm_get_timeouts(chip);
 622         tpm_do_selftest(chip);
 623
 624         return 0;
 625
 626 out_release:
 627         release_locality(chip, chip->vendor.locality, 1);
 628
 629 out_vendor:
 630         /* close file handles */
 631         tpm_dev_vendor_release(chip);
 632
 633         /* remove hardware */
 634         tpm_remove_hardware(chip->dev);
 635
 636         /* reset these pointers, otherwise we oops */
 637         chip->dev->release = NULL;
 638         chip->release = NULL;
 639         tpm_dev.client = NULL;
 640         dev_set_drvdata(chip->dev, chip);
 641 out_err:
 642         return rc;
 643 }
 644
 645 static const struct i2c_device_id tpm_tis_i2c_table[] = {
 646         {"tpm_i2c_infineon", 0},
 647         {},
 648 };
 649
 650 MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_table);
 651 static SIMPLE_DEV_PM_OPS(tpm_tis_i2c_ops, tpm_pm_suspend, tpm_pm_resume);
 652
 653 static int tpm_tis_i2c_probe(struct i2c_client *client,
 654                              const struct i2c_device_id *id)
 655 {
 656         int rc;
 657         if (tpm_dev.client != NULL)
 658                 return -EBUSY;  /* We only support one client */
 659
 660         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 661                 dev_err(&client->dev,
 662                         "no algorithms associated to the i2c bus\n");
 663                 return -ENODEV;
 664         }
 665
 666         client->driver = &tpm_tis_i2c_driver;
 667         tpm_dev.client = client;
 668         rc = tpm_tis_i2c_init(&client->dev);
 669         if (rc != 0) {
 670                 client->driver = NULL;
 671                 tpm_dev.client = NULL;
 672                 rc = -ENODEV;
 673         }
 674         return rc;
 675 }
 676
 677 static int tpm_tis_i2c_remove(struct i2c_client *client)
 678 {
 679         struct tpm_chip *chip = tpm_dev.chip;
 680         release_locality(chip, chip->vendor.locality, 1);
 681
 682         /* close file handles */
 683         tpm_dev_vendor_release(chip);
 684
 685         /* remove hardware */
 686         tpm_remove_hardware(chip->dev);
 687
 688         /* reset these pointers, otherwise we oops */
 689         chip->dev->release = NULL;
 690         chip->release = NULL;
 691         tpm_dev.client = NULL;
 692         dev_set_drvdata(chip->dev, chip);
 693
 694         return 0;
 695 }
 696
 697 static struct i2c_driver tpm_tis_i2c_driver = {
 698
 699         .id_table = tpm_tis_i2c_table,
 700         .probe = tpm_tis_i2c_probe,
 701         .remove = tpm_tis_i2c_remove,
 702         .driver = {
 703                    .name = "tpm_i2c_infineon",
 704                    .owner = THIS_MODULE,
 705                    .pm = &tpm_tis_i2c_ops,
 706                    },
 707 };
 708
 709 module_i2c_driver(tpm_tis_i2c_driver);
 710 MODULE_AUTHOR("Peter Huewe <peter.huewe@infineon.com>");
 711 MODULE_DESCRIPTION("TPM TIS I2C Infineon Driver");
 712 MODULE_VERSION("2.1.5");
 713 MODULE_LICENSE("GPL");