drivers/char/tpm/tpm_i2c_nuvoton.c

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