drivers/char/tpm/tpm_i2c_nuvoton.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2  /******************************************************************************
   3  * Nuvoton TPM I2C Device Driver Interface for WPCT301/NPCT501/NPCT6XX,
   4  * based on the TCG TPM Interface Spec version 1.2.
   5  * Specifications at www.trustedcomputinggroup.org
   6  *
   7  * Copyright (C) 2011, Nuvoton Technology Corporation.
   8  *  Dan Morav <dan.morav@nuvoton.com>
   9  * Copyright (C) 2013, Obsidian Research Corp.
  10  *  Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
  11  *
  12  * Nuvoton contact information: APC.Support@nuvoton.com
  13  *****************************************************************************/
  14
  15 #include <linux/init.h>
  16 #include <linux/module.h>
  17 #include <linux/moduleparam.h>
  18 #include <linux/slab.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/wait.h>
  21 #include <linux/i2c.h>
  22 #include <linux/of_device.h>
  23 #include "tpm.h"
  24
  25 /* I2C interface offsets */
  26 #define TPM_STS                 0x00
  27 #define TPM_BURST_COUNT         0x01
  28 #define TPM_DATA_FIFO_W         0x20
  29 #define TPM_DATA_FIFO_R         0x40
  30 #define TPM_VID_DID_RID         0x60
  31 #define TPM_I2C_RETRIES         5
  32 /*
  33  * I2C bus device maximum buffer size w/o counting I2C address or command
  34  * i.e. max size required for I2C write is 34 = addr, command, 32 bytes data
  35  */
  36 #define TPM_I2C_MAX_BUF_SIZE           32
  37 #define TPM_I2C_RETRY_COUNT            32
  38 #define TPM_I2C_BUS_DELAY              1000             /* usec */
  39 #define TPM_I2C_RETRY_DELAY_SHORT      (2 * 1000)       /* usec */
  40 #define TPM_I2C_RETRY_DELAY_LONG       (10 * 1000)      /* usec */
  41 #define TPM_I2C_DELAY_RANGE            300              /* usec */
  42
  43 #define OF_IS_TPM2 ((void *)1)
  44 #define I2C_IS_TPM2 1
  45
  46 struct priv_data {
  47         int irq;
  48         unsigned int intrs;
  49         wait_queue_head_t read_queue;
  50 };
  51
  52 static s32 i2c_nuvoton_read_buf(struct i2c_client *client, u8 offset, u8 size,
  53                                 u8 *data)
  54 {
  55         s32 status;
  56
  57         status = i2c_smbus_read_i2c_block_data(client, offset, size, data);
  58         dev_dbg(&client->dev,
  59                 "%s(offset=%u size=%u data=%*ph) -> sts=%d\n", __func__,
  60                 offset, size, (int)size, data, status);
  61         return status;
  62 }
  63
  64 static s32 i2c_nuvoton_write_buf(struct i2c_client *client, u8 offset, u8 size,
  65                                  u8 *data)
  66 {
  67         s32 status;
  68
  69         status = i2c_smbus_write_i2c_block_data(client, offset, size, data);
  70         dev_dbg(&client->dev,
  71                 "%s(offset=%u size=%u data=%*ph) -> sts=%d\n", __func__,
  72                 offset, size, (int)size, data, status);
  73         return status;
  74 }
  75
  76 #define TPM_STS_VALID          0x80
  77 #define TPM_STS_COMMAND_READY  0x40
  78 #define TPM_STS_GO             0x20
  79 #define TPM_STS_DATA_AVAIL     0x10
  80 #define TPM_STS_EXPECT         0x08
  81 #define TPM_STS_RESPONSE_RETRY 0x02
  82 #define TPM_STS_ERR_VAL        0x07    /* bit2...bit0 reads always 0 */
  83
  84 #define TPM_I2C_SHORT_TIMEOUT  750     /* ms */
  85 #define TPM_I2C_LONG_TIMEOUT   2000    /* 2 sec */
  86
  87 /* read TPM_STS register */
  88 static u8 i2c_nuvoton_read_status(struct tpm_chip *chip)
  89 {
  90         struct i2c_client *client = to_i2c_client(chip->dev.parent);
  91         s32 status;
  92         u8 data;
  93
  94         status = i2c_nuvoton_read_buf(client, TPM_STS, 1, &data);
  95         if (status <= 0) {
  96                 dev_err(&chip->dev, "%s() error return %d\n", __func__,
  97                         status);
  98                 data = TPM_STS_ERR_VAL;
  99         }
 100
 101         return data;
 102 }
 103
 104 /* write byte to TPM_STS register */
 105 static s32 i2c_nuvoton_write_status(struct i2c_client *client, u8 data)
 106 {
 107         s32 status;
 108         int i;
 109
 110         /* this causes the current command to be aborted */
 111         for (i = 0, status = -1; i < TPM_I2C_RETRY_COUNT && status < 0; i++) {
 112                 status = i2c_nuvoton_write_buf(client, TPM_STS, 1, &data);
 113                 if (status < 0)
 114                         usleep_range(TPM_I2C_BUS_DELAY, TPM_I2C_BUS_DELAY
 115                                      + TPM_I2C_DELAY_RANGE);
 116         }
 117         return status;
 118 }
 119
 120 /* write commandReady to TPM_STS register */
 121 static void i2c_nuvoton_ready(struct tpm_chip *chip)
 122 {
 123         struct i2c_client *client = to_i2c_client(chip->dev.parent);
 124         s32 status;
 125
 126         /* this causes the current command to be aborted */
 127         status = i2c_nuvoton_write_status(client, TPM_STS_COMMAND_READY);
 128         if (status < 0)
 129                 dev_err(&chip->dev,
 130                         "%s() fail to write TPM_STS.commandReady\n", __func__);
 131 }
 132
 133 /* read burstCount field from TPM_STS register
 134  * return -1 on fail to read */
 135 static int i2c_nuvoton_get_burstcount(struct i2c_client *client,
 136                                       struct tpm_chip *chip)
 137 {
 138         unsigned long stop = jiffies + chip->timeout_d;
 139         s32 status;
 140         int burst_count = -1;
 141         u8 data;
 142
 143         /* wait for burstcount to be non-zero */
 144         do {
 145                 /* in I2C burstCount is 1 byte */
 146                 status = i2c_nuvoton_read_buf(client, TPM_BURST_COUNT, 1,
 147                                               &data);
 148                 if (status > 0 && data > 0) {
 149                         burst_count = min_t(u8, TPM_I2C_MAX_BUF_SIZE, data);
 150                         break;
 151                 }
 152                 usleep_range(TPM_I2C_BUS_DELAY, TPM_I2C_BUS_DELAY
 153                              + TPM_I2C_DELAY_RANGE);
 154         } while (time_before(jiffies, stop));
 155
 156         return burst_count;
 157 }
 158
 159 /*
 160  * WPCT301/NPCT501/NPCT6XX SINT# supports only dataAvail
 161  * any call to this function which is not waiting for dataAvail will
 162  * set queue to NULL to avoid waiting for interrupt
 163  */
 164 static bool i2c_nuvoton_check_status(struct tpm_chip *chip, u8 mask, u8 value)
 165 {
 166         u8 status = i2c_nuvoton_read_status(chip);
 167         return (status != TPM_STS_ERR_VAL) && ((status & mask) == value);
 168 }
 169
 170 static int i2c_nuvoton_wait_for_stat(struct tpm_chip *chip, u8 mask, u8 value,
 171                                      u32 timeout, wait_queue_head_t *queue)
 172 {
 173         if ((chip->flags & TPM_CHIP_FLAG_IRQ) && queue) {
 174                 s32 rc;
 175                 struct priv_data *priv = dev_get_drvdata(&chip->dev);
 176                 unsigned int cur_intrs = priv->intrs;
 177
 178                 enable_irq(priv->irq);
 179                 rc = wait_event_interruptible_timeout(*queue,
 180                                                       cur_intrs != priv->intrs,
 181                                                       timeout);
 182                 if (rc > 0)
 183                         return 0;
 184                 /* At this point we know that the SINT pin is asserted, so we
 185                  * do not need to do i2c_nuvoton_check_status */
 186         } else {
 187                 unsigned long ten_msec, stop;
 188                 bool status_valid;
 189
 190                 /* check current status */
 191                 status_valid = i2c_nuvoton_check_status(chip, mask, value);
 192                 if (status_valid)
 193                         return 0;
 194
 195                 /* use polling to wait for the event */
 196                 ten_msec = jiffies + usecs_to_jiffies(TPM_I2C_RETRY_DELAY_LONG);
 197                 stop = jiffies + timeout;
 198                 do {
 199                         if (time_before(jiffies, ten_msec))
 200                                 usleep_range(TPM_I2C_RETRY_DELAY_SHORT,
 201                                              TPM_I2C_RETRY_DELAY_SHORT
 202                                              + TPM_I2C_DELAY_RANGE);
 203                         else
 204                                 usleep_range(TPM_I2C_RETRY_DELAY_LONG,
 205                                              TPM_I2C_RETRY_DELAY_LONG
 206                                              + TPM_I2C_DELAY_RANGE);
 207                         status_valid = i2c_nuvoton_check_status(chip, mask,
 208                                                                 value);
 209                         if (status_valid)
 210                                 return 0;
 211                 } while (time_before(jiffies, stop));
 212         }
 213         dev_err(&chip->dev, "%s(%02x, %02x) -> timeout\n", __func__, mask,
 214                 value);
 215         return -ETIMEDOUT;
 216 }
 217
 218 /* wait for dataAvail field to be set in the TPM_STS register */
 219 static int i2c_nuvoton_wait_for_data_avail(struct tpm_chip *chip, u32 timeout,
 220                                            wait_queue_head_t *queue)
 221 {
 222         return i2c_nuvoton_wait_for_stat(chip,
 223                                          TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 224                                          TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 225                                          timeout, queue);
 226 }
 227
 228 /* Read @count bytes into @buf from TPM_RD_FIFO register */
 229 static int i2c_nuvoton_recv_data(struct i2c_client *client,
 230                                  struct tpm_chip *chip, u8 *buf, size_t count)
 231 {
 232         struct priv_data *priv = dev_get_drvdata(&chip->dev);
 233         s32 rc;
 234         int burst_count, bytes2read, size = 0;
 235
 236         while (size < count &&
 237                i2c_nuvoton_wait_for_data_avail(chip,
 238                                                chip->timeout_c,
 239                                                &priv->read_queue) == 0) {
 240                 burst_count = i2c_nuvoton_get_burstcount(client, chip);
 241                 if (burst_count < 0) {
 242                         dev_err(&chip->dev,
 243                                 "%s() fail to read burstCount=%d\n", __func__,
 244                                 burst_count);
 245                         return -EIO;
 246                 }
 247                 bytes2read = min_t(size_t, burst_count, count - size);
 248                 rc = i2c_nuvoton_read_buf(client, TPM_DATA_FIFO_R,
 249                                           bytes2read, &buf[size]);
 250                 if (rc < 0) {
 251                         dev_err(&chip->dev,
 252                                 "%s() fail on i2c_nuvoton_read_buf()=%d\n",
 253                                 __func__, rc);
 254                         return -EIO;
 255                 }
 256                 dev_dbg(&chip->dev, "%s(%d):", __func__, bytes2read);
 257                 size += bytes2read;
 258         }
 259
 260         return size;
 261 }
 262
 263 /* Read TPM command results */
 264 static int i2c_nuvoton_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 265 {
 266         struct priv_data *priv = dev_get_drvdata(&chip->dev);
 267         struct device *dev = chip->dev.parent;
 268         struct i2c_client *client = to_i2c_client(dev);
 269         s32 rc;
 270         int status;
 271         int burst_count;
 272         int retries;
 273         int size = 0;
 274         u32 expected;
 275
 276         if (count < TPM_HEADER_SIZE) {
 277                 i2c_nuvoton_ready(chip);    /* return to idle */
 278                 dev_err(dev, "%s() count < header size\n", __func__);
 279                 return -EIO;
 280         }
 281         for (retries = 0; retries < TPM_I2C_RETRIES; retries++) {
 282                 if (retries > 0) {
 283                         /* if this is not the first trial, set responseRetry */
 284                         i2c_nuvoton_write_status(client,
 285                                                  TPM_STS_RESPONSE_RETRY);
 286                 }
 287                 /*
 288                  * read first available (> 10 bytes), including:
 289                  * tag, paramsize, and result
 290                  */
 291                 status = i2c_nuvoton_wait_for_data_avail(
 292                         chip, chip->timeout_c, &priv->read_queue);
 293                 if (status != 0) {
 294                         dev_err(dev, "%s() timeout on dataAvail\n", __func__);
 295                         size = -ETIMEDOUT;
 296                         continue;
 297                 }
 298                 burst_count = i2c_nuvoton_get_burstcount(client, chip);
 299                 if (burst_count < 0) {
 300                         dev_err(dev, "%s() fail to get burstCount\n", __func__);
 301                         size = -EIO;
 302                         continue;
 303                 }
 304                 size = i2c_nuvoton_recv_data(client, chip, buf,
 305                                              burst_count);
 306                 if (size < TPM_HEADER_SIZE) {
 307                         dev_err(dev, "%s() fail to read header\n", __func__);
 308                         size = -EIO;
 309                         continue;
 310                 }
 311                 /*
 312                  * convert number of expected bytes field from big endian 32 bit
 313                  * to machine native
 314                  */
 315                 expected = be32_to_cpu(*(__be32 *) (buf + 2));
 316                 if (expected > count || expected < size) {
 317                         dev_err(dev, "%s() expected > count\n", __func__);
 318                         size = -EIO;
 319                         continue;
 320                 }
 321                 rc = i2c_nuvoton_recv_data(client, chip, &buf[size],
 322                                            expected - size);
 323                 size += rc;
 324                 if (rc < 0 || size < expected) {
 325                         dev_err(dev, "%s() fail to read remainder of result\n",
 326                                 __func__);
 327                         size = -EIO;
 328                         continue;
 329                 }
 330                 if (i2c_nuvoton_wait_for_stat(
 331                             chip, TPM_STS_VALID | TPM_STS_DATA_AVAIL,
 332                             TPM_STS_VALID, chip->timeout_c,
 333                             NULL)) {
 334                         dev_err(dev, "%s() error left over data\n", __func__);
 335                         size = -ETIMEDOUT;
 336                         continue;
 337                 }
 338                 break;
 339         }
 340         i2c_nuvoton_ready(chip);
 341         dev_dbg(&chip->dev, "%s() -> %d\n", __func__, size);
 342         return size;
 343 }
 344
 345 /*
 346  * Send TPM command.
 347  *
 348  * If interrupts are used (signaled by an irq set in the vendor structure)
 349  * tpm.c can skip polling for the data to be available as the interrupt is
 350  * waited for here
 351  */
 352 static int i2c_nuvoton_send(struct tpm_chip *chip, u8 *buf, size_t len)
 353 {
 354         struct priv_data *priv = dev_get_drvdata(&chip->dev);
 355         struct device *dev = chip->dev.parent;
 356         struct i2c_client *client = to_i2c_client(dev);
 357         u32 ordinal;
 358         unsigned long duration;
 359         size_t count = 0;
 360         int burst_count, bytes2write, retries, rc = -EIO;
 361
 362         for (retries = 0; retries < TPM_RETRY; retries++) {
 363                 i2c_nuvoton_ready(chip);
 364                 if (i2c_nuvoton_wait_for_stat(chip, TPM_STS_COMMAND_READY,
 365                                               TPM_STS_COMMAND_READY,
 366                                               chip->timeout_b, NULL)) {
 367                         dev_err(dev, "%s() timeout on commandReady\n",
 368                                 __func__);
 369                         rc = -EIO;
 370                         continue;
 371                 }
 372                 rc = 0;
 373                 while (count < len - 1) {
 374                         burst_count = i2c_nuvoton_get_burstcount(client,
 375                                                                  chip);
 376                         if (burst_count < 0) {
 377                                 dev_err(dev, "%s() fail get burstCount\n",
 378                                         __func__);
 379                                 rc = -EIO;
 380                                 break;
 381                         }
 382                         bytes2write = min_t(size_t, burst_count,
 383                                             len - 1 - count);
 384                         rc = i2c_nuvoton_write_buf(client, TPM_DATA_FIFO_W,
 385                                                    bytes2write, &buf[count]);
 386                         if (rc < 0) {
 387                                 dev_err(dev, "%s() fail i2cWriteBuf\n",
 388                                         __func__);
 389                                 break;
 390                         }
 391                         dev_dbg(dev, "%s(%d):", __func__, bytes2write);
 392                         count += bytes2write;
 393                         rc = i2c_nuvoton_wait_for_stat(chip,
 394                                                        TPM_STS_VALID |
 395                                                        TPM_STS_EXPECT,
 396                                                        TPM_STS_VALID |
 397                                                        TPM_STS_EXPECT,
 398                                                        chip->timeout_c,
 399                                                        NULL);
 400                         if (rc < 0) {
 401                                 dev_err(dev, "%s() timeout on Expect\n",
 402                                         __func__);
 403                                 rc = -ETIMEDOUT;
 404                                 break;
 405                         }
 406                 }
 407                 if (rc < 0)
 408                         continue;
 409
 410                 /* write last byte */
 411                 rc = i2c_nuvoton_write_buf(client, TPM_DATA_FIFO_W, 1,
 412                                            &buf[count]);
 413                 if (rc < 0) {
 414                         dev_err(dev, "%s() fail to write last byte\n",
 415                                 __func__);
 416                         rc = -EIO;
 417                         continue;
 418                 }
 419                 dev_dbg(dev, "%s(last): %02x", __func__, buf[count]);
 420                 rc = i2c_nuvoton_wait_for_stat(chip,
 421                                                TPM_STS_VALID | TPM_STS_EXPECT,
 422                                                TPM_STS_VALID,
 423                                                chip->timeout_c, NULL);
 424                 if (rc) {
 425                         dev_err(dev, "%s() timeout on Expect to clear\n",
 426                                 __func__);
 427                         rc = -ETIMEDOUT;
 428                         continue;
 429                 }
 430                 break;
 431         }
 432         if (rc < 0) {
 433                 /* retries == TPM_RETRY */
 434                 i2c_nuvoton_ready(chip);
 435                 return rc;
 436         }
 437         /* execute the TPM command */
 438         rc = i2c_nuvoton_write_status(client, TPM_STS_GO);
 439         if (rc < 0) {
 440                 dev_err(dev, "%s() fail to write Go\n", __func__);
 441                 i2c_nuvoton_ready(chip);
 442                 return rc;
 443         }
 444         ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
 445         duration = tpm_calc_ordinal_duration(chip, ordinal);
 446
 447         rc = i2c_nuvoton_wait_for_data_avail(chip, duration, &priv->read_queue);
 448         if (rc) {
 449                 dev_err(dev, "%s() timeout command duration %ld\n",
 450                         __func__, duration);
 451                 i2c_nuvoton_ready(chip);
 452                 return rc;
 453         }
 454
 455         dev_dbg(dev, "%s() -> %zd\n", __func__, len);
 456         return 0;
 457 }
 458
 459 static bool i2c_nuvoton_req_canceled(struct tpm_chip *chip, u8 status)
 460 {
 461         return (status == TPM_STS_COMMAND_READY);
 462 }
 463
 464 static const struct tpm_class_ops tpm_i2c = {
 465         .flags = TPM_OPS_AUTO_STARTUP,
 466         .status = i2c_nuvoton_read_status,
 467         .recv = i2c_nuvoton_recv,
 468         .send = i2c_nuvoton_send,
 469         .cancel = i2c_nuvoton_ready,
 470         .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 471         .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 472         .req_canceled = i2c_nuvoton_req_canceled,
 473 };
 474
 475 /* The only purpose for the handler is to signal to any waiting threads that
 476  * the interrupt is currently being asserted. The driver does not do any
 477  * processing triggered by interrupts, and the chip provides no way to mask at
 478  * the source (plus that would be slow over I2C). Run the IRQ as a one-shot,
 479  * this means it cannot be shared. */
 480 static irqreturn_t i2c_nuvoton_int_handler(int dummy, void *dev_id)
 481 {
 482         struct tpm_chip *chip = dev_id;
 483         struct priv_data *priv = dev_get_drvdata(&chip->dev);
 484
 485         priv->intrs++;
 486         wake_up(&priv->read_queue);
 487         disable_irq_nosync(priv->irq);
 488         return IRQ_HANDLED;
 489 }
 490
 491 static int get_vid(struct i2c_client *client, u32 *res)
 492 {
 493         static const u8 vid_did_rid_value[] = { 0x50, 0x10, 0xfe };
 494         u32 temp;
 495         s32 rc;
 496
 497         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 498                 return -ENODEV;
 499         rc = i2c_nuvoton_read_buf(client, TPM_VID_DID_RID, 4, (u8 *)&temp);
 500         if (rc < 0)
 501                 return rc;
 502
 503         /* check WPCT301 values - ignore RID */
 504         if (memcmp(&temp, vid_did_rid_value, sizeof(vid_did_rid_value))) {
 505                 /*
 506                  * f/w rev 2.81 has an issue where the VID_DID_RID is not
 507                  * reporting the right value. so give it another chance at
 508                  * offset 0x20 (FIFO_W).
 509                  */
 510                 rc = i2c_nuvoton_read_buf(client, TPM_DATA_FIFO_W, 4,
 511                                           (u8 *) (&temp));
 512                 if (rc < 0)
 513                         return rc;
 514
 515                 /* check WPCT301 values - ignore RID */
 516                 if (memcmp(&temp, vid_did_rid_value,
 517                            sizeof(vid_did_rid_value)))
 518                         return -ENODEV;
 519         }
 520
 521         *res = temp;
 522         return 0;
 523 }
 524
 525 static int i2c_nuvoton_probe(struct i2c_client *client,
 526                              const struct i2c_device_id *id)
 527 {
 528         int rc;
 529         struct tpm_chip *chip;
 530         struct device *dev = &client->dev;
 531         struct priv_data *priv;
 532         u32 vid = 0;
 533
 534         rc = get_vid(client, &vid);
 535         if (rc)
 536                 return rc;
 537
 538         dev_info(dev, "VID: %04X DID: %02X RID: %02X\n", (u16) vid,
 539                  (u8) (vid >> 16), (u8) (vid >> 24));
 540
 541         chip = tpmm_chip_alloc(dev, &tpm_i2c);
 542         if (IS_ERR(chip))
 543                 return PTR_ERR(chip);
 544
 545         priv = devm_kzalloc(dev, sizeof(struct priv_data), GFP_KERNEL);
 546         if (!priv)
 547                 return -ENOMEM;
 548
 549         if (dev->of_node) {
 550                 const struct of_device_id *of_id;
 551
 552                 of_id = of_match_device(dev->driver->of_match_table, dev);
 553                 if (of_id && of_id->data == OF_IS_TPM2)
 554                         chip->flags |= TPM_CHIP_FLAG_TPM2;
 555         } else
 556                 if (id->driver_data == I2C_IS_TPM2)
 557                         chip->flags |= TPM_CHIP_FLAG_TPM2;
 558
 559         init_waitqueue_head(&priv->read_queue);
 560
 561         /* Default timeouts */
 562         chip->timeout_a = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
 563         chip->timeout_b = msecs_to_jiffies(TPM_I2C_LONG_TIMEOUT);
 564         chip->timeout_c = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
 565         chip->timeout_d = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
 566
 567         dev_set_drvdata(&chip->dev, priv);
 568
 569         /*
 570          * I2C intfcaps (interrupt capabilitieis) in the chip are hard coded to:
 571          *   TPM_INTF_INT_LEVEL_LOW | TPM_INTF_DATA_AVAIL_INT
 572          * The IRQ should be set in the i2c_board_info (which is done
 573          * automatically in of_i2c_register_devices, for device tree users */
 574         priv->irq = client->irq;
 575         if (client->irq) {
 576                 dev_dbg(dev, "%s() priv->irq\n", __func__);
 577                 rc = devm_request_irq(dev, client->irq,
 578                                       i2c_nuvoton_int_handler,
 579                                       IRQF_TRIGGER_LOW,
 580                                       dev_name(&chip->dev),
 581                                       chip);
 582                 if (rc) {
 583                         dev_err(dev, "%s() Unable to request irq: %d for use\n",
 584                                 __func__, priv->irq);
 585                         priv->irq = 0;
 586                 } else {
 587                         chip->flags |= TPM_CHIP_FLAG_IRQ;
 588                         /* Clear any pending interrupt */
 589                         i2c_nuvoton_ready(chip);
 590                         /* - wait for TPM_STS==0xA0 (stsValid, commandReady) */
 591                         rc = i2c_nuvoton_wait_for_stat(chip,
 592                                                        TPM_STS_COMMAND_READY,
 593                                                        TPM_STS_COMMAND_READY,
 594                                                        chip->timeout_b,
 595                                                        NULL);
 596                         if (rc == 0) {
 597                                 /*
 598                                  * TIS is in ready state
 599                                  * write dummy byte to enter reception state
 600                                  * TPM_DATA_FIFO_W <- rc (0)
 601                                  */
 602                                 rc = i2c_nuvoton_write_buf(client,
 603                                                            TPM_DATA_FIFO_W,
 604                                                            1, (u8 *) (&rc));
 605                                 if (rc < 0)
 606                                         return rc;
 607                                 /* TPM_STS <- 0x40 (commandReady) */
 608                                 i2c_nuvoton_ready(chip);
 609                         } else {
 610                                 /*
 611                                  * timeout_b reached - command was
 612                                  * aborted. TIS should now be in idle state -
 613                                  * only TPM_STS_VALID should be set
 614                                  */
 615                                 if (i2c_nuvoton_read_status(chip) !=
 616                                     TPM_STS_VALID)
 617                                         return -EIO;
 618                         }
 619                 }
 620         }
 621
 622         return tpm_chip_register(chip);
 623 }
 624
 625 static int i2c_nuvoton_remove(struct i2c_client *client)
 626 {
 627         struct tpm_chip *chip = i2c_get_clientdata(client);
 628
 629         tpm_chip_unregister(chip);
 630         return 0;
 631 }
 632
 633 static const struct i2c_device_id i2c_nuvoton_id[] = {
 634         {"tpm_i2c_nuvoton"},
 635         {"tpm2_i2c_nuvoton", .driver_data = I2C_IS_TPM2},
 636         {}
 637 };
 638 MODULE_DEVICE_TABLE(i2c, i2c_nuvoton_id);
 639
 640 #ifdef CONFIG_OF
 641 static const struct of_device_id i2c_nuvoton_of_match[] = {
 642         {.compatible = "nuvoton,npct501"},
 643         {.compatible = "winbond,wpct301"},
 644         {.compatible = "nuvoton,npct601", .data = OF_IS_TPM2},
 645         {},
 646 };
 647 MODULE_DEVICE_TABLE(of, i2c_nuvoton_of_match);
 648 #endif
 649
 650 static SIMPLE_DEV_PM_OPS(i2c_nuvoton_pm_ops, tpm_pm_suspend, tpm_pm_resume);
 651
 652 static struct i2c_driver i2c_nuvoton_driver = {
 653         .id_table = i2c_nuvoton_id,
 654         .probe = i2c_nuvoton_probe,
 655         .remove = i2c_nuvoton_remove,
 656         .driver = {
 657                 .name = "tpm_i2c_nuvoton",
 658                 .pm = &i2c_nuvoton_pm_ops,
 659                 .of_match_table = of_match_ptr(i2c_nuvoton_of_match),
 660         },
 661 };
 662
 663 module_i2c_driver(i2c_nuvoton_driver);
 664
 665 MODULE_AUTHOR("Dan Morav (dan.morav@nuvoton.com)");
 666 MODULE_DESCRIPTION("Nuvoton TPM I2C Driver");
 667 MODULE_LICENSE("GPL");