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/miscdevice.h>
  22 #include <linux/kernel.h>
  23 #include <linux/delay.h>
  24 #include <linux/wait.h>
  25 #include <linux/freezer.h>
  26 #include <linux/string.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/gpio.h>
  29 #include <linux/sched.h>
  30 #include <linux/uaccess.h>
  31 #include <linux/io.h>
  32 #include <linux/slab.h>
  33
  34 #include "../tpm.h"
  35 #include "st33zp24.h"
  36
  37 #define TPM_ACCESS                      0x0
  38 #define TPM_STS                         0x18
  39 #define TPM_DATA_FIFO                   0x24
  40 #define TPM_INTF_CAPABILITY             0x14
  41 #define TPM_INT_STATUS                  0x10
  42 #define TPM_INT_ENABLE                  0x08
  43
  44 #define LOCALITY0                       0
  45
  46 enum st33zp24_access {
  47         TPM_ACCESS_VALID = 0x80,
  48         TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
  49         TPM_ACCESS_REQUEST_PENDING = 0x04,
  50         TPM_ACCESS_REQUEST_USE = 0x02,
  51 };
  52
  53 enum st33zp24_status {
  54         TPM_STS_VALID = 0x80,
  55         TPM_STS_COMMAND_READY = 0x40,
  56         TPM_STS_GO = 0x20,
  57         TPM_STS_DATA_AVAIL = 0x10,
  58         TPM_STS_DATA_EXPECT = 0x08,
  59 };
  60
  61 enum st33zp24_int_flags {
  62         TPM_GLOBAL_INT_ENABLE = 0x80,
  63         TPM_INTF_CMD_READY_INT = 0x080,
  64         TPM_INTF_FIFO_AVALAIBLE_INT = 0x040,
  65         TPM_INTF_WAKE_UP_READY_INT = 0x020,
  66         TPM_INTF_LOCALITY_CHANGE_INT = 0x004,
  67         TPM_INTF_STS_VALID_INT = 0x002,
  68         TPM_INTF_DATA_AVAIL_INT = 0x001,
  69 };
  70
  71 enum tis_defaults {
  72         TIS_SHORT_TIMEOUT = 750,
  73         TIS_LONG_TIMEOUT = 2000,
  74 };
  75
  76 /*
  77  * clear_interruption clear the pending interrupt.
  78  * @param: tpm_dev, the tpm device device.
  79  * @return: the interrupt status value.
  80  */
  81 static u8 clear_interruption(struct st33zp24_dev *tpm_dev)
  82 {
  83         u8 interrupt;
  84
  85         tpm_dev->ops->recv(tpm_dev->phy_id, TPM_INT_STATUS, &interrupt, 1);
  86         tpm_dev->ops->send(tpm_dev->phy_id, TPM_INT_STATUS, &interrupt, 1);
  87         return interrupt;
  88 } /* clear_interruption() */
  89
  90 /*
  91  * st33zp24_cancel, cancel the current command execution or
  92  * set STS to COMMAND READY.
  93  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h
  94  */
  95 static void st33zp24_cancel(struct tpm_chip *chip)
  96 {
  97         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
  98         u8 data;
  99
 100         data = TPM_STS_COMMAND_READY;
 101         tpm_dev->ops->send(tpm_dev->phy_id, TPM_STS, &data, 1);
 102 } /* st33zp24_cancel() */
 103
 104 /*
 105  * st33zp24_status return the TPM_STS register
 106  * @param: chip, the tpm chip description
 107  * @return: the TPM_STS register value.
 108  */
 109 static u8 st33zp24_status(struct tpm_chip *chip)
 110 {
 111         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 112         u8 data;
 113
 114         tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS, &data, 1);
 115         return data;
 116 } /* st33zp24_status() */
 117
 118 /*
 119  * check_locality if the locality is active
 120  * @param: chip, the tpm chip description
 121  * @return: the active locality or -EACCESS.
 122  */
 123 static int check_locality(struct tpm_chip *chip)
 124 {
 125         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 126         u8 data;
 127         u8 status;
 128
 129         status = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
 130         if (status && (data &
 131                 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
 132                 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
 133                 return tpm_dev->locality;
 134
 135         return -EACCES;
 136 } /* check_locality() */
 137
 138 /*
 139  * request_locality request the TPM locality
 140  * @param: chip, the chip description
 141  * @return: the active locality or negative value.
 142  */
 143 static int request_locality(struct tpm_chip *chip)
 144 {
 145         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 146         unsigned long stop;
 147         long ret;
 148         u8 data;
 149
 150         if (check_locality(chip) == tpm_dev->locality)
 151                 return tpm_dev->locality;
 152
 153         data = TPM_ACCESS_REQUEST_USE;
 154         ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
 155         if (ret < 0)
 156                 return ret;
 157
 158         stop = jiffies + chip->timeout_a;
 159
 160         /* Request locality is usually effective after the request */
 161         do {
 162                 if (check_locality(chip) >= 0)
 163                         return tpm_dev->locality;
 164                 msleep(TPM_TIMEOUT);
 165         } while (time_before(jiffies, stop));
 166
 167         /* could not get locality */
 168         return -EACCES;
 169 } /* request_locality() */
 170
 171 /*
 172  * release_locality release the active locality
 173  * @param: chip, the tpm chip description.
 174  */
 175 static void release_locality(struct tpm_chip *chip)
 176 {
 177         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 178         u8 data;
 179
 180         data = TPM_ACCESS_ACTIVE_LOCALITY;
 181
 182         tpm_dev->ops->send(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
 183 }
 184
 185 /*
 186  * get_burstcount return the burstcount value
 187  * @param: chip, the chip description
 188  * return: the burstcount or negative value.
 189  */
 190 static int get_burstcount(struct tpm_chip *chip)
 191 {
 192         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 193         unsigned long stop;
 194         int burstcnt, status;
 195         u8 temp;
 196
 197         stop = jiffies + chip->timeout_d;
 198         do {
 199                 status = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS + 1,
 200                                             &temp, 1);
 201                 if (status < 0)
 202                         return -EBUSY;
 203
 204                 burstcnt = temp;
 205                 status = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS + 2,
 206                                             &temp, 1);
 207                 if (status < 0)
 208                         return -EBUSY;
 209
 210                 burstcnt |= temp << 8;
 211                 if (burstcnt)
 212                         return burstcnt;
 213                 msleep(TPM_TIMEOUT);
 214         } while (time_before(jiffies, stop));
 215         return -EBUSY;
 216 } /* get_burstcount() */
 217
 218
 219 /*
 220  * wait_for_tpm_stat_cond
 221  * @param: chip, chip description
 222  * @param: mask, expected mask value
 223  * @param: check_cancel, does the command expected to be canceled ?
 224  * @param: canceled, did we received a cancel request ?
 225  * @return: true if status == mask or if the command is canceled.
 226  * false in other cases.
 227  */
 228 static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask,
 229                                 bool check_cancel, bool *canceled)
 230 {
 231         u8 status = chip->ops->status(chip);
 232
 233         *canceled = false;
 234         if ((status & mask) == mask)
 235                 return true;
 236         if (check_cancel && chip->ops->req_canceled(chip, status)) {
 237                 *canceled = true;
 238                 return true;
 239         }
 240         return false;
 241 }
 242
 243 /*
 244  * wait_for_stat wait for a TPM_STS value
 245  * @param: chip, the tpm chip description
 246  * @param: mask, the value mask to wait
 247  * @param: timeout, the timeout
 248  * @param: queue, the wait queue.
 249  * @param: check_cancel, does the command can be cancelled ?
 250  * @return: the tpm status, 0 if success, -ETIME if timeout is reached.
 251  */
 252 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
 253                         wait_queue_head_t *queue, bool check_cancel)
 254 {
 255         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 256         unsigned long stop;
 257         int ret = 0;
 258         bool canceled = false;
 259         bool condition;
 260         u32 cur_intrs;
 261         u8 status;
 262
 263         /* check current status */
 264         status = st33zp24_status(chip);
 265         if ((status & mask) == mask)
 266                 return 0;
 267
 268         stop = jiffies + timeout;
 269
 270         if (chip->flags & TPM_CHIP_FLAG_IRQ) {
 271                 cur_intrs = tpm_dev->intrs;
 272                 clear_interruption(tpm_dev);
 273                 enable_irq(tpm_dev->irq);
 274
 275                 do {
 276                         if (ret == -ERESTARTSYS && freezing(current))
 277                                 clear_thread_flag(TIF_SIGPENDING);
 278
 279                         timeout = stop - jiffies;
 280                         if ((long) timeout <= 0)
 281                                 return -1;
 282
 283                         ret = wait_event_interruptible_timeout(*queue,
 284                                                 cur_intrs != tpm_dev->intrs,
 285                                                 timeout);
 286                         clear_interruption(tpm_dev);
 287                         condition = wait_for_tpm_stat_cond(chip, mask,
 288                                                 check_cancel, &canceled);
 289                         if (ret >= 0 && condition) {
 290                                 if (canceled)
 291                                         return -ECANCELED;
 292                                 return 0;
 293                         }
 294                 } while (ret == -ERESTARTSYS && freezing(current));
 295
 296                 disable_irq_nosync(tpm_dev->irq);
 297
 298         } else {
 299                 do {
 300                         msleep(TPM_TIMEOUT);
 301                         status = chip->ops->status(chip);
 302                         if ((status & mask) == mask)
 303                                 return 0;
 304                 } while (time_before(jiffies, stop));
 305         }
 306
 307         return -ETIME;
 308 } /* wait_for_stat() */
 309
 310 /*
 311  * recv_data receive data
 312  * @param: chip, the tpm chip description
 313  * @param: buf, the buffer where the data are received
 314  * @param: count, the number of data to receive
 315  * @return: the number of bytes read from TPM FIFO.
 316  */
 317 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
 318 {
 319         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 320         int size = 0, burstcnt, len, ret;
 321
 322         while (size < count &&
 323                wait_for_stat(chip,
 324                              TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 325                              chip->timeout_c,
 326                              &tpm_dev->read_queue, true) == 0) {
 327                 burstcnt = get_burstcount(chip);
 328                 if (burstcnt < 0)
 329                         return burstcnt;
 330                 len = min_t(int, burstcnt, count - size);
 331                 ret = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_DATA_FIFO,
 332                                          buf + size, len);
 333                 if (ret < 0)
 334                         return ret;
 335
 336                 size += len;
 337         }
 338         return size;
 339 }
 340
 341 /*
 342  * tpm_ioserirq_handler the serirq irq handler
 343  * @param: irq, the tpm chip description
 344  * @param: dev_id, the description of the chip
 345  * @return: the status of the handler.
 346  */
 347 static irqreturn_t tpm_ioserirq_handler(int irq, void *dev_id)
 348 {
 349         struct tpm_chip *chip = dev_id;
 350         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 351
 352         tpm_dev->intrs++;
 353         wake_up_interruptible(&tpm_dev->read_queue);
 354         disable_irq_nosync(tpm_dev->irq);
 355
 356         return IRQ_HANDLED;
 357 } /* tpm_ioserirq_handler() */
 358
 359 /*
 360  * st33zp24_send send TPM commands through the I2C bus.
 361  *
 362  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h
 363  * @param: buf, the buffer to send.
 364  * @param: count, the number of bytes to send.
 365  * @return: In case of success the number of bytes sent.
 366  *                      In other case, a < 0 value describing the issue.
 367  */
 368 static int st33zp24_send(struct tpm_chip *chip, unsigned char *buf,
 369                          size_t len)
 370 {
 371         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 372         u32 status, i, size, ordinal;
 373         int burstcnt = 0;
 374         int ret;
 375         u8 data;
 376
 377         if (!chip)
 378                 return -EBUSY;
 379         if (len < TPM_HEADER_SIZE)
 380                 return -EBUSY;
 381
 382         ret = request_locality(chip);
 383         if (ret < 0)
 384                 return ret;
 385
 386         status = st33zp24_status(chip);
 387         if ((status & TPM_STS_COMMAND_READY) == 0) {
 388                 st33zp24_cancel(chip);
 389                 if (wait_for_stat
 390                     (chip, TPM_STS_COMMAND_READY, chip->timeout_b,
 391                      &tpm_dev->read_queue, false) < 0) {
 392                         ret = -ETIME;
 393                         goto out_err;
 394                 }
 395         }
 396
 397         for (i = 0; i < len - 1;) {
 398                 burstcnt = get_burstcount(chip);
 399                 if (burstcnt < 0)
 400                         return burstcnt;
 401                 size = min_t(int, len - i - 1, burstcnt);
 402                 ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_DATA_FIFO,
 403                                          buf + i, size);
 404                 if (ret < 0)
 405                         goto out_err;
 406
 407                 i += size;
 408         }
 409
 410         status = st33zp24_status(chip);
 411         if ((status & TPM_STS_DATA_EXPECT) == 0) {
 412                 ret = -EIO;
 413                 goto out_err;
 414         }
 415
 416         ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_DATA_FIFO,
 417                                  buf + len - 1, 1);
 418         if (ret < 0)
 419                 goto out_err;
 420
 421         status = st33zp24_status(chip);
 422         if ((status & TPM_STS_DATA_EXPECT) != 0) {
 423                 ret = -EIO;
 424                 goto out_err;
 425         }
 426
 427         data = TPM_STS_GO;
 428         ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_STS, &data, 1);
 429         if (ret < 0)
 430                 goto out_err;
 431
 432         if (chip->flags & TPM_CHIP_FLAG_IRQ) {
 433                 ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
 434
 435                 ret = wait_for_stat(chip, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 436                                 tpm_calc_ordinal_duration(chip, ordinal),
 437                                 &tpm_dev->read_queue, false);
 438                 if (ret < 0)
 439                         goto out_err;
 440         }
 441
 442         return len;
 443 out_err:
 444         st33zp24_cancel(chip);
 445         release_locality(chip);
 446         return ret;
 447 }
 448
 449 /*
 450  * st33zp24_recv received TPM response through TPM phy.
 451  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h.
 452  * @param: buf, the buffer to store datas.
 453  * @param: count, the number of bytes to send.
 454  * @return: In case of success the number of bytes received.
 455  *          In other case, a < 0 value describing the issue.
 456  */
 457 static int st33zp24_recv(struct tpm_chip *chip, unsigned char *buf,
 458                             size_t count)
 459 {
 460         int size = 0;
 461         int expected;
 462
 463         if (!chip)
 464                 return -EBUSY;
 465
 466         if (count < TPM_HEADER_SIZE) {
 467                 size = -EIO;
 468                 goto out;
 469         }
 470
 471         size = recv_data(chip, buf, TPM_HEADER_SIZE);
 472         if (size < TPM_HEADER_SIZE) {
 473                 dev_err(&chip->dev, "Unable to read header\n");
 474                 goto out;
 475         }
 476
 477         expected = be32_to_cpu(*(__be32 *)(buf + 2));
 478         if (expected > count) {
 479                 size = -EIO;
 480                 goto out;
 481         }
 482
 483         size += recv_data(chip, &buf[TPM_HEADER_SIZE],
 484                         expected - TPM_HEADER_SIZE);
 485         if (size < expected) {
 486                 dev_err(&chip->dev, "Unable to read remainder of result\n");
 487                 size = -ETIME;
 488         }
 489
 490 out:
 491         st33zp24_cancel(chip);
 492         release_locality(chip);
 493         return size;
 494 }
 495
 496 /*
 497  * st33zp24_req_canceled
 498  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h.
 499  * @param: status, the TPM status.
 500  * @return: Does TPM ready to compute a new command ? true.
 501  */
 502 static bool st33zp24_req_canceled(struct tpm_chip *chip, u8 status)
 503 {
 504         return (status == TPM_STS_COMMAND_READY);
 505 }
 506
 507 static const struct tpm_class_ops st33zp24_tpm = {
 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                 tpm_gen_interrupt(chip);
 593         }
 594
 595         tpm_get_timeouts(chip);
 596         tpm_do_selftest(chip);
 597
 598         return tpm_chip_register(chip);
 599 _tpm_clean_answer:
 600         dev_info(&chip->dev, "TPM initialization fail\n");
 601         return ret;
 602 }
 603 EXPORT_SYMBOL(st33zp24_probe);
 604
 605 /*
 606  * st33zp24_remove remove the TPM device
 607  * @param: tpm_data, the tpm phy.
 608  * @return: 0 in case of success.
 609  */
 610 int st33zp24_remove(struct tpm_chip *chip)
 611 {
 612         tpm_chip_unregister(chip);
 613         return 0;
 614 }
 615 EXPORT_SYMBOL(st33zp24_remove);
 616
 617 #ifdef CONFIG_PM_SLEEP
 618 /*
 619  * st33zp24_pm_suspend suspend the TPM device
 620  * @param: tpm_data, the tpm phy.
 621  * @param: mesg, the power management message.
 622  * @return: 0 in case of success.
 623  */
 624 int st33zp24_pm_suspend(struct device *dev)
 625 {
 626         struct tpm_chip *chip = dev_get_drvdata(dev);
 627         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 628
 629         int ret = 0;
 630
 631         if (gpio_is_valid(tpm_dev->io_lpcpd))
 632                 gpio_set_value(tpm_dev->io_lpcpd, 0);
 633         else
 634                 ret = tpm_pm_suspend(dev);
 635
 636         return ret;
 637 } /* st33zp24_pm_suspend() */
 638 EXPORT_SYMBOL(st33zp24_pm_suspend);
 639
 640 /*
 641  * st33zp24_pm_resume resume the TPM device
 642  * @param: tpm_data, the tpm phy.
 643  * @return: 0 in case of success.
 644  */
 645 int st33zp24_pm_resume(struct device *dev)
 646 {
 647         struct tpm_chip *chip = dev_get_drvdata(dev);
 648         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 649         int ret = 0;
 650
 651         if (gpio_is_valid(tpm_dev->io_lpcpd)) {
 652                 gpio_set_value(tpm_dev->io_lpcpd, 1);
 653                 ret = wait_for_stat(chip,
 654                                 TPM_STS_VALID, chip->timeout_b,
 655                                 &tpm_dev->read_queue, false);
 656         } else {
 657                 ret = tpm_pm_resume(dev);
 658                 if (!ret)
 659                         tpm_do_selftest(chip);
 660         }
 661         return ret;
 662 } /* st33zp24_pm_resume() */
 663 EXPORT_SYMBOL(st33zp24_pm_resume);
 664 #endif
 665
 666 MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
 667 MODULE_DESCRIPTION("ST33ZP24 TPM 1.2 driver");
 668 MODULE_VERSION("1.3.0");
 669 MODULE_LICENSE("GPL");