drivers/char/tpm/st33zp24/st33zp24.c

   1 /*
   2  * STMicroelectronics TPM Linux driver for TPM ST33ZP24
   3  * Copyright (C) 2009 - 2016 STMicroelectronics
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/fs.h>
  21 #include <linux/kernel.h>
  22 #include <linux/delay.h>
  23 #include <linux/wait.h>
  24 #include <linux/freezer.h>
  25 #include <linux/string.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/gpio.h>
  28 #include <linux/sched.h>
  29 #include <linux/uaccess.h>
  30 #include <linux/io.h>
  31 #include <linux/slab.h>
  32
  33 #include "../tpm.h"
  34 #include "st33zp24.h"
  35
  36 #define TPM_ACCESS                      0x0
  37 #define TPM_STS                         0x18
  38 #define TPM_DATA_FIFO                   0x24
  39 #define TPM_INTF_CAPABILITY             0x14
  40 #define TPM_INT_STATUS                  0x10
  41 #define TPM_INT_ENABLE                  0x08
  42
  43 #define LOCALITY0                       0
  44
  45 enum st33zp24_access {
  46         TPM_ACCESS_VALID = 0x80,
  47         TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
  48         TPM_ACCESS_REQUEST_PENDING = 0x04,
  49         TPM_ACCESS_REQUEST_USE = 0x02,
  50 };
  51
  52 enum st33zp24_status {
  53         TPM_STS_VALID = 0x80,
  54         TPM_STS_COMMAND_READY = 0x40,
  55         TPM_STS_GO = 0x20,
  56         TPM_STS_DATA_AVAIL = 0x10,
  57         TPM_STS_DATA_EXPECT = 0x08,
  58 };
  59
  60 enum st33zp24_int_flags {
  61         TPM_GLOBAL_INT_ENABLE = 0x80,
  62         TPM_INTF_CMD_READY_INT = 0x080,
  63         TPM_INTF_FIFO_AVALAIBLE_INT = 0x040,
  64         TPM_INTF_WAKE_UP_READY_INT = 0x020,
  65         TPM_INTF_LOCALITY_CHANGE_INT = 0x004,
  66         TPM_INTF_STS_VALID_INT = 0x002,
  67         TPM_INTF_DATA_AVAIL_INT = 0x001,
  68 };
  69
  70 enum tis_defaults {
  71         TIS_SHORT_TIMEOUT = 750,
  72         TIS_LONG_TIMEOUT = 2000,
  73 };
  74
  75 /*
  76  * clear_interruption clear the pending interrupt.
  77  * @param: tpm_dev, the tpm device device.
  78  * @return: the interrupt status value.
  79  */
  80 static u8 clear_interruption(struct st33zp24_dev *tpm_dev)
  81 {
  82         u8 interrupt;
  83
  84         tpm_dev->ops->recv(tpm_dev->phy_id, TPM_INT_STATUS, &interrupt, 1);
  85         tpm_dev->ops->send(tpm_dev->phy_id, TPM_INT_STATUS, &interrupt, 1);
  86         return interrupt;
  87 } /* clear_interruption() */
  88
  89 /*
  90  * st33zp24_cancel, cancel the current command execution or
  91  * set STS to COMMAND READY.
  92  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h
  93  */
  94 static void st33zp24_cancel(struct tpm_chip *chip)
  95 {
  96         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
  97         u8 data;
  98
  99         data = TPM_STS_COMMAND_READY;
 100         tpm_dev->ops->send(tpm_dev->phy_id, TPM_STS, &data, 1);
 101 } /* st33zp24_cancel() */
 102
 103 /*
 104  * st33zp24_status return the TPM_STS register
 105  * @param: chip, the tpm chip description
 106  * @return: the TPM_STS register value.
 107  */
 108 static u8 st33zp24_status(struct tpm_chip *chip)
 109 {
 110         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 111         u8 data;
 112
 113         tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS, &data, 1);
 114         return data;
 115 } /* st33zp24_status() */
 116
 117 /*
 118  * check_locality if the locality is active
 119  * @param: chip, the tpm chip description
 120  * @return: true if LOCALITY0 is active, otherwise false
 121  */
 122 static bool check_locality(struct tpm_chip *chip)
 123 {
 124         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 125         u8 data;
 126         u8 status;
 127
 128         status = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
 129         if (status && (data &
 130                 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
 131                 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
 132                 return true;
 133
 134         return false;
 135 } /* check_locality() */
 136
 137 /*
 138  * request_locality request the TPM locality
 139  * @param: chip, the chip description
 140  * @return: the active locality or negative value.
 141  */
 142 static int request_locality(struct tpm_chip *chip)
 143 {
 144         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 145         unsigned long stop;
 146         long ret;
 147         u8 data;
 148
 149         if (check_locality(chip))
 150                 return tpm_dev->locality;
 151
 152         data = TPM_ACCESS_REQUEST_USE;
 153         ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
 154         if (ret < 0)
 155                 return ret;
 156
 157         stop = jiffies + chip->timeout_a;
 158
 159         /* Request locality is usually effective after the request */
 160         do {
 161                 if (check_locality(chip))
 162                         return tpm_dev->locality;
 163                 msleep(TPM_TIMEOUT);
 164         } while (time_before(jiffies, stop));
 165
 166         /* could not get locality */
 167         return -EACCES;
 168 } /* request_locality() */
 169
 170 /*
 171  * release_locality release the active locality
 172  * @param: chip, the tpm chip description.
 173  */
 174 static void release_locality(struct tpm_chip *chip)
 175 {
 176         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 177         u8 data;
 178
 179         data = TPM_ACCESS_ACTIVE_LOCALITY;
 180
 181         tpm_dev->ops->send(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
 182 }
 183
 184 /*
 185  * get_burstcount return the burstcount value
 186  * @param: chip, the chip description
 187  * return: the burstcount or negative value.
 188  */
 189 static int get_burstcount(struct tpm_chip *chip)
 190 {
 191         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 192         unsigned long stop;
 193         int burstcnt, status;
 194         u8 temp;
 195
 196         stop = jiffies + chip->timeout_d;
 197         do {
 198                 status = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS + 1,
 199                                             &temp, 1);
 200                 if (status < 0)
 201                         return -EBUSY;
 202
 203                 burstcnt = temp;
 204                 status = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS + 2,
 205                                             &temp, 1);
 206                 if (status < 0)
 207                         return -EBUSY;
 208
 209                 burstcnt |= temp << 8;
 210                 if (burstcnt)
 211                         return burstcnt;
 212                 msleep(TPM_TIMEOUT);
 213         } while (time_before(jiffies, stop));
 214         return -EBUSY;
 215 } /* get_burstcount() */
 216
 217
 218 /*
 219  * wait_for_tpm_stat_cond
 220  * @param: chip, chip description
 221  * @param: mask, expected mask value
 222  * @param: check_cancel, does the command expected to be canceled ?
 223  * @param: canceled, did we received a cancel request ?
 224  * @return: true if status == mask or if the command is canceled.
 225  * false in other cases.
 226  */
 227 static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask,
 228                                 bool check_cancel, bool *canceled)
 229 {
 230         u8 status = chip->ops->status(chip);
 231
 232         *canceled = false;
 233         if ((status & mask) == mask)
 234                 return true;
 235         if (check_cancel && chip->ops->req_canceled(chip, status)) {
 236                 *canceled = true;
 237                 return true;
 238         }
 239         return false;
 240 }
 241
 242 /*
 243  * wait_for_stat wait for a TPM_STS value
 244  * @param: chip, the tpm chip description
 245  * @param: mask, the value mask to wait
 246  * @param: timeout, the timeout
 247  * @param: queue, the wait queue.
 248  * @param: check_cancel, does the command can be cancelled ?
 249  * @return: the tpm status, 0 if success, -ETIME if timeout is reached.
 250  */
 251 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
 252                         wait_queue_head_t *queue, bool check_cancel)
 253 {
 254         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 255         unsigned long stop;
 256         int ret = 0;
 257         bool canceled = false;
 258         bool condition;
 259         u32 cur_intrs;
 260         u8 status;
 261
 262         /* check current status */
 263         status = st33zp24_status(chip);
 264         if ((status & mask) == mask)
 265                 return 0;
 266
 267         stop = jiffies + timeout;
 268
 269         if (chip->flags & TPM_CHIP_FLAG_IRQ) {
 270                 cur_intrs = tpm_dev->intrs;
 271                 clear_interruption(tpm_dev);
 272                 enable_irq(tpm_dev->irq);
 273
 274                 do {
 275                         if (ret == -ERESTARTSYS && freezing(current))
 276                                 clear_thread_flag(TIF_SIGPENDING);
 277
 278                         timeout = stop - jiffies;
 279                         if ((long) timeout <= 0)
 280                                 return -1;
 281
 282                         ret = wait_event_interruptible_timeout(*queue,
 283                                                 cur_intrs != tpm_dev->intrs,
 284                                                 timeout);
 285                         clear_interruption(tpm_dev);
 286                         condition = wait_for_tpm_stat_cond(chip, mask,
 287                                                 check_cancel, &canceled);
 288                         if (ret >= 0 && condition) {
 289                                 if (canceled)
 290                                         return -ECANCELED;
 291                                 return 0;
 292                         }
 293                 } while (ret == -ERESTARTSYS && freezing(current));
 294
 295                 disable_irq_nosync(tpm_dev->irq);
 296
 297         } else {
 298                 do {
 299                         msleep(TPM_TIMEOUT);
 300                         status = chip->ops->status(chip);
 301                         if ((status & mask) == mask)
 302                                 return 0;
 303                 } while (time_before(jiffies, stop));
 304         }
 305
 306         return -ETIME;
 307 } /* wait_for_stat() */
 308
 309 /*
 310  * recv_data receive data
 311  * @param: chip, the tpm chip description
 312  * @param: buf, the buffer where the data are received
 313  * @param: count, the number of data to receive
 314  * @return: the number of bytes read from TPM FIFO.
 315  */
 316 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
 317 {
 318         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 319         int size = 0, burstcnt, len, ret;
 320
 321         while (size < count &&
 322                wait_for_stat(chip,
 323                              TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 324                              chip->timeout_c,
 325                              &tpm_dev->read_queue, true) == 0) {
 326                 burstcnt = get_burstcount(chip);
 327                 if (burstcnt < 0)
 328                         return burstcnt;
 329                 len = min_t(int, burstcnt, count - size);
 330                 ret = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_DATA_FIFO,
 331                                          buf + size, len);
 332                 if (ret < 0)
 333                         return ret;
 334
 335                 size += len;
 336         }
 337         return size;
 338 }
 339
 340 /*
 341  * tpm_ioserirq_handler the serirq irq handler
 342  * @param: irq, the tpm chip description
 343  * @param: dev_id, the description of the chip
 344  * @return: the status of the handler.
 345  */
 346 static irqreturn_t tpm_ioserirq_handler(int irq, void *dev_id)
 347 {
 348         struct tpm_chip *chip = dev_id;
 349         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 350
 351         tpm_dev->intrs++;
 352         wake_up_interruptible(&tpm_dev->read_queue);
 353         disable_irq_nosync(tpm_dev->irq);
 354
 355         return IRQ_HANDLED;
 356 } /* tpm_ioserirq_handler() */
 357
 358 /*
 359  * st33zp24_send send TPM commands through the I2C bus.
 360  *
 361  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h
 362  * @param: buf, the buffer to send.
 363  * @param: count, the number of bytes to send.
 364  * @return: In case of success the number of bytes sent.
 365  *                      In other case, a < 0 value describing the issue.
 366  */
 367 static int st33zp24_send(struct tpm_chip *chip, unsigned char *buf,
 368                          size_t len)
 369 {
 370         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 371         u32 status, i, size, ordinal;
 372         int burstcnt = 0;
 373         int ret;
 374         u8 data;
 375
 376         if (!chip)
 377                 return -EBUSY;
 378         if (len < TPM_HEADER_SIZE)
 379                 return -EBUSY;
 380
 381         ret = request_locality(chip);
 382         if (ret < 0)
 383                 return ret;
 384
 385         status = st33zp24_status(chip);
 386         if ((status & TPM_STS_COMMAND_READY) == 0) {
 387                 st33zp24_cancel(chip);
 388                 if (wait_for_stat
 389                     (chip, TPM_STS_COMMAND_READY, chip->timeout_b,
 390                      &tpm_dev->read_queue, false) < 0) {
 391                         ret = -ETIME;
 392                         goto out_err;
 393                 }
 394         }
 395
 396         for (i = 0; i < len - 1;) {
 397                 burstcnt = get_burstcount(chip);
 398                 if (burstcnt < 0)
 399                         return burstcnt;
 400                 size = min_t(int, len - i - 1, burstcnt);
 401                 ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_DATA_FIFO,
 402                                          buf + i, size);
 403                 if (ret < 0)
 404                         goto out_err;
 405
 406                 i += size;
 407         }
 408
 409         status = st33zp24_status(chip);
 410         if ((status & TPM_STS_DATA_EXPECT) == 0) {
 411                 ret = -EIO;
 412                 goto out_err;
 413         }
 414
 415         ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_DATA_FIFO,
 416                                  buf + len - 1, 1);
 417         if (ret < 0)
 418                 goto out_err;
 419
 420         status = st33zp24_status(chip);
 421         if ((status & TPM_STS_DATA_EXPECT) != 0) {
 422                 ret = -EIO;
 423                 goto out_err;
 424         }
 425
 426         data = TPM_STS_GO;
 427         ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_STS, &data, 1);
 428         if (ret < 0)
 429                 goto out_err;
 430
 431         if (chip->flags & TPM_CHIP_FLAG_IRQ) {
 432                 ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
 433
 434                 ret = wait_for_stat(chip, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 435                                 tpm_calc_ordinal_duration(chip, ordinal),
 436                                 &tpm_dev->read_queue, false);
 437                 if (ret < 0)
 438                         goto out_err;
 439         }
 440
 441         return len;
 442 out_err:
 443         st33zp24_cancel(chip);
 444         release_locality(chip);
 445         return ret;
 446 }
 447
 448 /*
 449  * st33zp24_recv received TPM response through TPM phy.
 450  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h.
 451  * @param: buf, the buffer to store datas.
 452  * @param: count, the number of bytes to send.
 453  * @return: In case of success the number of bytes received.
 454  *          In other case, a < 0 value describing the issue.
 455  */
 456 static int st33zp24_recv(struct tpm_chip *chip, unsigned char *buf,
 457                             size_t count)
 458 {
 459         int size = 0;
 460         u32 expected;
 461
 462         if (!chip)
 463                 return -EBUSY;
 464
 465         if (count < TPM_HEADER_SIZE) {
 466                 size = -EIO;
 467                 goto out;
 468         }
 469
 470         size = recv_data(chip, buf, TPM_HEADER_SIZE);
 471         if (size < TPM_HEADER_SIZE) {
 472                 dev_err(&chip->dev, "Unable to read header\n");
 473                 goto out;
 474         }
 475
 476         expected = be32_to_cpu(*(__be32 *)(buf + 2));
 477         if (expected > count || expected < TPM_HEADER_SIZE) {
 478                 size = -EIO;
 479                 goto out;
 480         }
 481
 482         size += recv_data(chip, &buf[TPM_HEADER_SIZE],
 483                         expected - TPM_HEADER_SIZE);
 484         if (size < expected) {
 485                 dev_err(&chip->dev, "Unable to read remainder of result\n");
 486                 size = -ETIME;
 487         }
 488
 489 out:
 490         st33zp24_cancel(chip);
 491         release_locality(chip);
 492         return size;
 493 }
 494
 495 /*
 496  * st33zp24_req_canceled
 497  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h.
 498  * @param: status, the TPM status.
 499  * @return: Does TPM ready to compute a new command ? true.
 500  */
 501 static bool st33zp24_req_canceled(struct tpm_chip *chip, u8 status)
 502 {
 503         return (status == TPM_STS_COMMAND_READY);
 504 }
 505
 506 static const struct tpm_class_ops st33zp24_tpm = {
 507         .flags = TPM_OPS_AUTO_STARTUP,
 508         .send = st33zp24_send,
 509         .recv = st33zp24_recv,
 510         .cancel = st33zp24_cancel,
 511         .status = st33zp24_status,
 512         .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 513         .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 514         .req_canceled = st33zp24_req_canceled,
 515 };
 516
 517 /*
 518  * st33zp24_probe initialize the TPM device
 519  * @param: client, the i2c_client drescription (TPM I2C description).
 520  * @param: id, the i2c_device_id struct.
 521  * @return: 0 in case of success.
 522  *       -1 in other case.
 523  */
 524 int st33zp24_probe(void *phy_id, const struct st33zp24_phy_ops *ops,
 525                    struct device *dev, int irq, int io_lpcpd)
 526 {
 527         int ret;
 528         u8 intmask = 0;
 529         struct tpm_chip *chip;
 530         struct st33zp24_dev *tpm_dev;
 531
 532         chip = tpmm_chip_alloc(dev, &st33zp24_tpm);
 533         if (IS_ERR(chip))
 534                 return PTR_ERR(chip);
 535
 536         tpm_dev = devm_kzalloc(dev, sizeof(struct st33zp24_dev),
 537                                GFP_KERNEL);
 538         if (!tpm_dev)
 539                 return -ENOMEM;
 540
 541         tpm_dev->phy_id = phy_id;
 542         tpm_dev->ops = ops;
 543         dev_set_drvdata(&chip->dev, tpm_dev);
 544
 545         chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 546         chip->timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
 547         chip->timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 548         chip->timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 549
 550         tpm_dev->locality = LOCALITY0;
 551
 552         if (irq) {
 553                 /* INTERRUPT Setup */
 554                 init_waitqueue_head(&tpm_dev->read_queue);
 555                 tpm_dev->intrs = 0;
 556
 557                 if (request_locality(chip) != LOCALITY0) {
 558                         ret = -ENODEV;
 559                         goto _tpm_clean_answer;
 560                 }
 561
 562                 clear_interruption(tpm_dev);
 563                 ret = devm_request_irq(dev, irq, tpm_ioserirq_handler,
 564                                 IRQF_TRIGGER_HIGH, "TPM SERIRQ management",
 565                                 chip);
 566                 if (ret < 0) {
 567                         dev_err(&chip->dev, "TPM SERIRQ signals %d not available\n",
 568                                 irq);
 569                         goto _tpm_clean_answer;
 570                 }
 571
 572                 intmask |= TPM_INTF_CMD_READY_INT
 573                         |  TPM_INTF_STS_VALID_INT
 574                         |  TPM_INTF_DATA_AVAIL_INT;
 575
 576                 ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_INT_ENABLE,
 577                                          &intmask, 1);
 578                 if (ret < 0)
 579                         goto _tpm_clean_answer;
 580
 581                 intmask = TPM_GLOBAL_INT_ENABLE;
 582                 ret = tpm_dev->ops->send(tpm_dev->phy_id, (TPM_INT_ENABLE + 3),
 583                                          &intmask, 1);
 584                 if (ret < 0)
 585                         goto _tpm_clean_answer;
 586
 587                 tpm_dev->irq = irq;
 588                 chip->flags |= TPM_CHIP_FLAG_IRQ;
 589
 590                 disable_irq_nosync(tpm_dev->irq);
 591         }
 592
 593         return tpm_chip_register(chip);
 594 _tpm_clean_answer:
 595         dev_info(&chip->dev, "TPM initialization fail\n");
 596         return ret;
 597 }
 598 EXPORT_SYMBOL(st33zp24_probe);
 599
 600 /*
 601  * st33zp24_remove remove the TPM device
 602  * @param: tpm_data, the tpm phy.
 603  * @return: 0 in case of success.
 604  */
 605 int st33zp24_remove(struct tpm_chip *chip)
 606 {
 607         tpm_chip_unregister(chip);
 608         return 0;
 609 }
 610 EXPORT_SYMBOL(st33zp24_remove);
 611
 612 #ifdef CONFIG_PM_SLEEP
 613 /*
 614  * st33zp24_pm_suspend suspend the TPM device
 615  * @param: tpm_data, the tpm phy.
 616  * @param: mesg, the power management message.
 617  * @return: 0 in case of success.
 618  */
 619 int st33zp24_pm_suspend(struct device *dev)
 620 {
 621         struct tpm_chip *chip = dev_get_drvdata(dev);
 622         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 623
 624         int ret = 0;
 625
 626         if (gpio_is_valid(tpm_dev->io_lpcpd))
 627                 gpio_set_value(tpm_dev->io_lpcpd, 0);
 628         else
 629                 ret = tpm_pm_suspend(dev);
 630
 631         return ret;
 632 } /* st33zp24_pm_suspend() */
 633 EXPORT_SYMBOL(st33zp24_pm_suspend);
 634
 635 /*
 636  * st33zp24_pm_resume resume the TPM device
 637  * @param: tpm_data, the tpm phy.
 638  * @return: 0 in case of success.
 639  */
 640 int st33zp24_pm_resume(struct device *dev)
 641 {
 642         struct tpm_chip *chip = dev_get_drvdata(dev);
 643         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 644         int ret = 0;
 645
 646         if (gpio_is_valid(tpm_dev->io_lpcpd)) {
 647                 gpio_set_value(tpm_dev->io_lpcpd, 1);
 648                 ret = wait_for_stat(chip,
 649                                 TPM_STS_VALID, chip->timeout_b,
 650                                 &tpm_dev->read_queue, false);
 651         } else {
 652                 ret = tpm_pm_resume(dev);
 653                 if (!ret)
 654                         tpm_do_selftest(chip);
 655         }
 656         return ret;
 657 } /* st33zp24_pm_resume() */
 658 EXPORT_SYMBOL(st33zp24_pm_resume);
 659 #endif
 660
 661 MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
 662 MODULE_DESCRIPTION("ST33ZP24 TPM 1.2 driver");
 663 MODULE_VERSION("1.3.0");
 664 MODULE_LICENSE("GPL");