kernel/drivers/char/tpm/st33zp24/st33zp24.c

   1 /*
   2  * STMicroelectronics TPM Linux driver for TPM ST33ZP24
   3  * Copyright (C) 2009 - 2015 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 struct st33zp24_dev {
  77         struct tpm_chip *chip;
  78         void *phy_id;
  79         const struct st33zp24_phy_ops *ops;
  80         u32 intrs;
  81         int io_lpcpd;
  82 };
  83
  84 /*
  85  * clear_interruption clear the pending interrupt.
  86  * @param: tpm_dev, the tpm device device.
  87  * @return: the interrupt status value.
  88  */
  89 static u8 clear_interruption(struct st33zp24_dev *tpm_dev)
  90 {
  91         u8 interrupt;
  92
  93         tpm_dev->ops->recv(tpm_dev->phy_id, TPM_INT_STATUS, &interrupt, 1);
  94         tpm_dev->ops->send(tpm_dev->phy_id, TPM_INT_STATUS, &interrupt, 1);
  95         return interrupt;
  96 } /* clear_interruption() */
  97
  98 /*
  99  * st33zp24_cancel, cancel the current command execution or
 100  * set STS to COMMAND READY.
 101  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h
 102  */
 103 static void st33zp24_cancel(struct tpm_chip *chip)
 104 {
 105         struct st33zp24_dev *tpm_dev;
 106         u8 data;
 107
 108         tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
 109
 110         data = TPM_STS_COMMAND_READY;
 111         tpm_dev->ops->send(tpm_dev->phy_id, TPM_STS, &data, 1);
 112 } /* st33zp24_cancel() */
 113
 114 /*
 115  * st33zp24_status return the TPM_STS register
 116  * @param: chip, the tpm chip description
 117  * @return: the TPM_STS register value.
 118  */
 119 static u8 st33zp24_status(struct tpm_chip *chip)
 120 {
 121         struct st33zp24_dev *tpm_dev;
 122         u8 data;
 123
 124         tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
 125
 126         tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS, &data, 1);
 127         return data;
 128 } /* st33zp24_status() */
 129
 130 /*
 131  * check_locality if the locality is active
 132  * @param: chip, the tpm chip description
 133  * @return: the active locality or -EACCESS.
 134  */
 135 static int check_locality(struct tpm_chip *chip)
 136 {
 137         struct st33zp24_dev *tpm_dev;
 138         u8 data;
 139         u8 status;
 140
 141         tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
 142
 143         status = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
 144         if (status && (data &
 145                 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
 146                 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
 147                 return chip->vendor.locality;
 148
 149         return -EACCES;
 150 } /* check_locality() */
 151
 152 /*
 153  * request_locality request the TPM locality
 154  * @param: chip, the chip description
 155  * @return: the active locality or negative value.
 156  */
 157 static int request_locality(struct tpm_chip *chip)
 158 {
 159         unsigned long stop;
 160         long ret;
 161         struct st33zp24_dev *tpm_dev;
 162         u8 data;
 163
 164         if (check_locality(chip) == chip->vendor.locality)
 165                 return chip->vendor.locality;
 166
 167         tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
 168
 169         data = TPM_ACCESS_REQUEST_USE;
 170         ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
 171         if (ret < 0)
 172                 return ret;
 173
 174         stop = jiffies + chip->vendor.timeout_a;
 175
 176         /* Request locality is usually effective after the request */
 177         do {
 178                 if (check_locality(chip) >= 0)
 179                         return chip->vendor.locality;
 180                 msleep(TPM_TIMEOUT);
 181         } while (time_before(jiffies, stop));
 182
 183         /* could not get locality */
 184         return -EACCES;
 185 } /* request_locality() */
 186
 187 /*
 188  * release_locality release the active locality
 189  * @param: chip, the tpm chip description.
 190  */
 191 static void release_locality(struct tpm_chip *chip)
 192 {
 193         struct st33zp24_dev *tpm_dev;
 194         u8 data;
 195
 196         tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
 197         data = TPM_ACCESS_ACTIVE_LOCALITY;
 198
 199         tpm_dev->ops->send(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
 200 }
 201
 202 /*
 203  * get_burstcount return the burstcount value
 204  * @param: chip, the chip description
 205  * return: the burstcount or negative value.
 206  */
 207 static int get_burstcount(struct tpm_chip *chip)
 208 {
 209         unsigned long stop;
 210         int burstcnt, status;
 211         u8 tpm_reg, temp;
 212         struct st33zp24_dev *tpm_dev;
 213
 214         tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
 215
 216         stop = jiffies + chip->vendor.timeout_d;
 217         do {
 218                 tpm_reg = TPM_STS + 1;
 219                 status = tpm_dev->ops->recv(tpm_dev->phy_id, tpm_reg, &temp, 1);
 220                 if (status < 0)
 221                         return -EBUSY;
 222
 223                 tpm_reg = TPM_STS + 2;
 224                 burstcnt = temp;
 225                 status = tpm_dev->ops->recv(tpm_dev->phy_id, tpm_reg, &temp, 1);
 226                 if (status < 0)
 227                         return -EBUSY;
 228
 229                 burstcnt |= temp << 8;
 230                 if (burstcnt)
 231                         return burstcnt;
 232                 msleep(TPM_TIMEOUT);
 233         } while (time_before(jiffies, stop));
 234         return -EBUSY;
 235 } /* get_burstcount() */
 236
 237
 238 /*
 239  * wait_for_tpm_stat_cond
 240  * @param: chip, chip description
 241  * @param: mask, expected mask value
 242  * @param: check_cancel, does the command expected to be canceled ?
 243  * @param: canceled, did we received a cancel request ?
 244  * @return: true if status == mask or if the command is canceled.
 245  * false in other cases.
 246  */
 247 static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask,
 248                                 bool check_cancel, bool *canceled)
 249 {
 250         u8 status = chip->ops->status(chip);
 251
 252         *canceled = false;
 253         if ((status & mask) == mask)
 254                 return true;
 255         if (check_cancel && chip->ops->req_canceled(chip, status)) {
 256                 *canceled = true;
 257                 return true;
 258         }
 259         return false;
 260 }
 261
 262 /*
 263  * wait_for_stat wait for a TPM_STS value
 264  * @param: chip, the tpm chip description
 265  * @param: mask, the value mask to wait
 266  * @param: timeout, the timeout
 267  * @param: queue, the wait queue.
 268  * @param: check_cancel, does the command can be cancelled ?
 269  * @return: the tpm status, 0 if success, -ETIME if timeout is reached.
 270  */
 271 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
 272                         wait_queue_head_t *queue, bool check_cancel)
 273 {
 274         unsigned long stop;
 275         int ret = 0;
 276         bool canceled = false;
 277         bool condition;
 278         u32 cur_intrs;
 279         u8 status;
 280         struct st33zp24_dev *tpm_dev;
 281
 282         tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
 283
 284         /* check current status */
 285         status = st33zp24_status(chip);
 286         if ((status & mask) == mask)
 287                 return 0;
 288
 289         stop = jiffies + timeout;
 290
 291         if (chip->vendor.irq) {
 292                 cur_intrs = tpm_dev->intrs;
 293                 clear_interruption(tpm_dev);
 294                 enable_irq(chip->vendor.irq);
 295
 296                 do {
 297                         if (ret == -ERESTARTSYS && freezing(current))
 298                                 clear_thread_flag(TIF_SIGPENDING);
 299
 300                         timeout = stop - jiffies;
 301                         if ((long) timeout <= 0)
 302                                 return -1;
 303
 304                         ret = wait_event_interruptible_timeout(*queue,
 305                                                 cur_intrs != tpm_dev->intrs,
 306                                                 timeout);
 307                         clear_interruption(tpm_dev);
 308                         condition = wait_for_tpm_stat_cond(chip, mask,
 309                                                 check_cancel, &canceled);
 310                         if (ret >= 0 && condition) {
 311                                 if (canceled)
 312                                         return -ECANCELED;
 313                                 return 0;
 314                         }
 315                 } while (ret == -ERESTARTSYS && freezing(current));
 316
 317                 disable_irq_nosync(chip->vendor.irq);
 318
 319         } else {
 320                 do {
 321                         msleep(TPM_TIMEOUT);
 322                         status = chip->ops->status(chip);
 323                         if ((status & mask) == mask)
 324                                 return 0;
 325                 } while (time_before(jiffies, stop));
 326         }
 327
 328         return -ETIME;
 329 } /* wait_for_stat() */
 330
 331 /*
 332  * recv_data receive data
 333  * @param: chip, the tpm chip description
 334  * @param: buf, the buffer where the data are received
 335  * @param: count, the number of data to receive
 336  * @return: the number of bytes read from TPM FIFO.
 337  */
 338 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
 339 {
 340         int size = 0, burstcnt, len, ret;
 341         struct st33zp24_dev *tpm_dev;
 342
 343         tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
 344
 345         while (size < count &&
 346                wait_for_stat(chip,
 347                              TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 348                              chip->vendor.timeout_c,
 349                              &chip->vendor.read_queue, true) == 0) {
 350                 burstcnt = get_burstcount(chip);
 351                 if (burstcnt < 0)
 352                         return burstcnt;
 353                 len = min_t(int, burstcnt, count - size);
 354                 ret = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_DATA_FIFO,
 355                                          buf + size, len);
 356                 if (ret < 0)
 357                         return ret;
 358
 359                 size += len;
 360         }
 361         return size;
 362 }
 363
 364 /*
 365  * tpm_ioserirq_handler the serirq irq handler
 366  * @param: irq, the tpm chip description
 367  * @param: dev_id, the description of the chip
 368  * @return: the status of the handler.
 369  */
 370 static irqreturn_t tpm_ioserirq_handler(int irq, void *dev_id)
 371 {
 372         struct tpm_chip *chip = dev_id;
 373         struct st33zp24_dev *tpm_dev;
 374
 375         tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
 376
 377         tpm_dev->intrs++;
 378         wake_up_interruptible(&chip->vendor.read_queue);
 379         disable_irq_nosync(chip->vendor.irq);
 380
 381         return IRQ_HANDLED;
 382 } /* tpm_ioserirq_handler() */
 383
 384 /*
 385  * st33zp24_send send TPM commands through the I2C bus.
 386  *
 387  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h
 388  * @param: buf, the buffer to send.
 389  * @param: count, the number of bytes to send.
 390  * @return: In case of success the number of bytes sent.
 391  *                      In other case, a < 0 value describing the issue.
 392  */
 393 static int st33zp24_send(struct tpm_chip *chip, unsigned char *buf,
 394                          size_t len)
 395 {
 396         u32 status, i, size, ordinal;
 397         int burstcnt = 0;
 398         int ret;
 399         u8 data;
 400         struct st33zp24_dev *tpm_dev;
 401
 402         if (!chip)
 403                 return -EBUSY;
 404         if (len < TPM_HEADER_SIZE)
 405                 return -EBUSY;
 406
 407         tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
 408
 409         ret = request_locality(chip);
 410         if (ret < 0)
 411                 return ret;
 412
 413         status = st33zp24_status(chip);
 414         if ((status & TPM_STS_COMMAND_READY) == 0) {
 415                 st33zp24_cancel(chip);
 416                 if (wait_for_stat
 417                     (chip, TPM_STS_COMMAND_READY, chip->vendor.timeout_b,
 418                      &chip->vendor.read_queue, false) < 0) {
 419                         ret = -ETIME;
 420                         goto out_err;
 421                 }
 422         }
 423
 424         for (i = 0; i < len - 1;) {
 425                 burstcnt = get_burstcount(chip);
 426                 if (burstcnt < 0)
 427                         return burstcnt;
 428                 size = min_t(int, len - i - 1, burstcnt);
 429                 ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_DATA_FIFO,
 430                                          buf + i, size);
 431                 if (ret < 0)
 432                         goto out_err;
 433
 434                 i += size;
 435         }
 436
 437         status = st33zp24_status(chip);
 438         if ((status & TPM_STS_DATA_EXPECT) == 0) {
 439                 ret = -EIO;
 440                 goto out_err;
 441         }
 442
 443         ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_DATA_FIFO,
 444                                  buf + len - 1, 1);
 445         if (ret < 0)
 446                 goto out_err;
 447
 448         status = st33zp24_status(chip);
 449         if ((status & TPM_STS_DATA_EXPECT) != 0) {
 450                 ret = -EIO;
 451                 goto out_err;
 452         }
 453
 454         data = TPM_STS_GO;
 455         ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_STS, &data, 1);
 456         if (ret < 0)
 457                 goto out_err;
 458
 459         if (chip->vendor.irq) {
 460                 ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
 461
 462                 ret = wait_for_stat(chip, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 463                                 tpm_calc_ordinal_duration(chip, ordinal),
 464                                 &chip->vendor.read_queue, false);
 465                 if (ret < 0)
 466                         goto out_err;
 467         }
 468
 469         return len;
 470 out_err:
 471         st33zp24_cancel(chip);
 472         release_locality(chip);
 473         return ret;
 474 }
 475
 476 /*
 477  * st33zp24_recv received TPM response through TPM phy.
 478  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h.
 479  * @param: buf, the buffer to store datas.
 480  * @param: count, the number of bytes to send.
 481  * @return: In case of success the number of bytes received.
 482  *          In other case, a < 0 value describing the issue.
 483  */
 484 static int st33zp24_recv(struct tpm_chip *chip, unsigned char *buf,
 485                             size_t count)
 486 {
 487         int size = 0;
 488         int expected;
 489
 490         if (!chip)
 491                 return -EBUSY;
 492
 493         if (count < TPM_HEADER_SIZE) {
 494                 size = -EIO;
 495                 goto out;
 496         }
 497
 498         size = recv_data(chip, buf, TPM_HEADER_SIZE);
 499         if (size < TPM_HEADER_SIZE) {
 500                 dev_err(&chip->dev, "Unable to read header\n");
 501                 goto out;
 502         }
 503
 504         expected = be32_to_cpu(*(__be32 *)(buf + 2));
 505         if (expected > count) {
 506                 size = -EIO;
 507                 goto out;
 508         }
 509
 510         size += recv_data(chip, &buf[TPM_HEADER_SIZE],
 511                         expected - TPM_HEADER_SIZE);
 512         if (size < expected) {
 513                 dev_err(&chip->dev, "Unable to read remainder of result\n");
 514                 size = -ETIME;
 515         }
 516
 517 out:
 518         st33zp24_cancel(chip);
 519         release_locality(chip);
 520         return size;
 521 }
 522
 523 /*
 524  * st33zp24_req_canceled
 525  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h.
 526  * @param: status, the TPM status.
 527  * @return: Does TPM ready to compute a new command ? true.
 528  */
 529 static bool st33zp24_req_canceled(struct tpm_chip *chip, u8 status)
 530 {
 531         return (status == TPM_STS_COMMAND_READY);
 532 }
 533
 534 static const struct tpm_class_ops st33zp24_tpm = {
 535         .send = st33zp24_send,
 536         .recv = st33zp24_recv,
 537         .cancel = st33zp24_cancel,
 538         .status = st33zp24_status,
 539         .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 540         .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 541         .req_canceled = st33zp24_req_canceled,
 542 };
 543
 544 /*
 545  * st33zp24_probe initialize the TPM device
 546  * @param: client, the i2c_client drescription (TPM I2C description).
 547  * @param: id, the i2c_device_id struct.
 548  * @return: 0 in case of success.
 549  *       -1 in other case.
 550  */
 551 int st33zp24_probe(void *phy_id, const struct st33zp24_phy_ops *ops,
 552                    struct device *dev, int irq, int io_lpcpd)
 553 {
 554         int ret;
 555         u8 intmask = 0;
 556         struct tpm_chip *chip;
 557         struct st33zp24_dev *tpm_dev;
 558
 559         chip = tpmm_chip_alloc(dev, &st33zp24_tpm);
 560         if (IS_ERR(chip))
 561                 return PTR_ERR(chip);
 562
 563         tpm_dev = devm_kzalloc(dev, sizeof(struct st33zp24_dev),
 564                                GFP_KERNEL);
 565         if (!tpm_dev)
 566                 return -ENOMEM;
 567
 568         TPM_VPRIV(chip) = tpm_dev;
 569         tpm_dev->phy_id = phy_id;
 570         tpm_dev->ops = ops;
 571
 572         chip->vendor.timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 573         chip->vendor.timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
 574         chip->vendor.timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 575         chip->vendor.timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
 576
 577         chip->vendor.locality = LOCALITY0;
 578
 579         if (irq) {
 580                 /* INTERRUPT Setup */
 581                 init_waitqueue_head(&chip->vendor.read_queue);
 582                 tpm_dev->intrs = 0;
 583
 584                 if (request_locality(chip) != LOCALITY0) {
 585                         ret = -ENODEV;
 586                         goto _tpm_clean_answer;
 587                 }
 588
 589                 clear_interruption(tpm_dev);
 590                 ret = devm_request_irq(dev, irq, tpm_ioserirq_handler,
 591                                 IRQF_TRIGGER_HIGH, "TPM SERIRQ management",
 592                                 chip);
 593                 if (ret < 0) {
 594                         dev_err(&chip->dev, "TPM SERIRQ signals %d not available\n",
 595                                 irq);
 596                         goto _tpm_clean_answer;
 597                 }
 598
 599                 intmask |= TPM_INTF_CMD_READY_INT
 600                         |  TPM_INTF_STS_VALID_INT
 601                         |  TPM_INTF_DATA_AVAIL_INT;
 602
 603                 ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_INT_ENABLE,
 604                                          &intmask, 1);
 605                 if (ret < 0)
 606                         goto _tpm_clean_answer;
 607
 608                 intmask = TPM_GLOBAL_INT_ENABLE;
 609                 ret = tpm_dev->ops->send(tpm_dev->phy_id, (TPM_INT_ENABLE + 3),
 610                                          &intmask, 1);
 611                 if (ret < 0)
 612                         goto _tpm_clean_answer;
 613
 614                 chip->vendor.irq = irq;
 615
 616                 disable_irq_nosync(chip->vendor.irq);
 617
 618                 tpm_gen_interrupt(chip);
 619         }
 620
 621         tpm_get_timeouts(chip);
 622         tpm_do_selftest(chip);
 623
 624         return tpm_chip_register(chip);
 625 _tpm_clean_answer:
 626         dev_info(&chip->dev, "TPM initialization fail\n");
 627         return ret;
 628 }
 629 EXPORT_SYMBOL(st33zp24_probe);
 630
 631 /*
 632  * st33zp24_remove remove the TPM device
 633  * @param: tpm_data, the tpm phy.
 634  * @return: 0 in case of success.
 635  */
 636 int st33zp24_remove(struct tpm_chip *chip)
 637 {
 638         tpm_chip_unregister(chip);
 639         return 0;
 640 }
 641 EXPORT_SYMBOL(st33zp24_remove);
 642
 643 #ifdef CONFIG_PM_SLEEP
 644 /*
 645  * st33zp24_pm_suspend suspend the TPM device
 646  * @param: tpm_data, the tpm phy.
 647  * @param: mesg, the power management message.
 648  * @return: 0 in case of success.
 649  */
 650 int st33zp24_pm_suspend(struct device *dev)
 651 {
 652         struct tpm_chip *chip = dev_get_drvdata(dev);
 653         struct st33zp24_dev *tpm_dev;
 654         int ret = 0;
 655
 656         tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
 657
 658         if (gpio_is_valid(tpm_dev->io_lpcpd))
 659                 gpio_set_value(tpm_dev->io_lpcpd, 0);
 660         else
 661                 ret = tpm_pm_suspend(dev);
 662
 663         return ret;
 664 } /* st33zp24_pm_suspend() */
 665 EXPORT_SYMBOL(st33zp24_pm_suspend);
 666
 667 /*
 668  * st33zp24_pm_resume resume the TPM device
 669  * @param: tpm_data, the tpm phy.
 670  * @return: 0 in case of success.
 671  */
 672 int st33zp24_pm_resume(struct device *dev)
 673 {
 674         struct tpm_chip *chip = dev_get_drvdata(dev);
 675         struct st33zp24_dev *tpm_dev;
 676         int ret = 0;
 677
 678         tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
 679
 680         if (gpio_is_valid(tpm_dev->io_lpcpd)) {
 681                 gpio_set_value(tpm_dev->io_lpcpd, 1);
 682                 ret = wait_for_stat(chip,
 683                                 TPM_STS_VALID, chip->vendor.timeout_b,
 684                                 &chip->vendor.read_queue, false);
 685         } else {
 686                 ret = tpm_pm_resume(dev);
 687                 if (!ret)
 688                         tpm_do_selftest(chip);
 689         }
 690         return ret;
 691 } /* st33zp24_pm_resume() */
 692 EXPORT_SYMBOL(st33zp24_pm_resume);
 693 #endif
 694
 695 MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
 696 MODULE_DESCRIPTION("ST33ZP24 TPM 1.2 driver");
 697 MODULE_VERSION("1.3.0");
 698 MODULE_LICENSE("GPL");