drivers/mfd/cros_ec_spi.c

   1 /*
   2  * ChromeOS EC multi-function device (SPI)
   3  *
   4  * Copyright (C) 2012 Google, Inc
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   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
  16 #include <linux/delay.h>
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/mfd/cros_ec.h>
  20 #include <linux/mfd/cros_ec_commands.h>
  21 #include <linux/of.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/slab.h>
  24 #include <linux/spi/spi.h>
  25
  26
  27 /* The header byte, which follows the preamble */
  28 #define EC_MSG_HEADER                   0xec
  29
  30 /*
  31  * Number of EC preamble bytes we read at a time. Since it takes
  32  * about 400-500us for the EC to respond there is not a lot of
  33  * point in tuning this. If the EC could respond faster then
  34  * we could increase this so that might expect the preamble and
  35  * message to occur in a single transaction. However, the maximum
  36  * SPI transfer size is 256 bytes, so at 5MHz we need a response
  37  * time of perhaps <320us (200 bytes / 1600 bits).
  38  */
  39 #define EC_MSG_PREAMBLE_COUNT           32
  40
  41 /*
  42  * Allow for a long time for the EC to respond.  We support i2c
  43  * tunneling and support fairly long messages for the tunnel (249
  44  * bytes long at the moment).  If we're talking to a 100 kHz device
  45  * on the other end and need to transfer ~256 bytes, then we need:
  46  *  10 us/bit * ~10 bits/byte * ~256 bytes = ~25ms
  47  *
  48  * We'll wait 8 times that to handle clock stretching and other
  49  * paranoia.  Note that some battery gas gauge ICs claim to have a
  50  * clock stretch of 144ms in rare situations.  That's incentive for
  51  * not directly passing i2c through, but it's too late for that for
  52  * existing hardware.
  53  *
  54  * It's pretty unlikely that we'll really see a 249 byte tunnel in
  55  * anything other than testing.  If this was more common we might
  56  * consider having slow commands like this require a GET_STATUS
  57  * wait loop.  The 'flash write' command would be another candidate
  58  * for this, clocking in at 2-3ms.
  59  */
  60 #define EC_MSG_DEADLINE_MS              200
  61
  62 /*
  63   * Time between raising the SPI chip select (for the end of a
  64   * transaction) and dropping it again (for the next transaction).
  65   * If we go too fast, the EC will miss the transaction. We know that we
  66   * need at least 70 us with the 16 MHz STM32 EC, so go with 200 us to be
  67   * safe.
  68   */
  69 #define EC_SPI_RECOVERY_TIME_NS (200 * 1000)
  70
  71 /**
  72  * struct cros_ec_spi - information about a SPI-connected EC
  73  *
  74  * @spi: SPI device we are connected to
  75  * @last_transfer_ns: time that we last finished a transfer, or 0 if there
  76  *      if no record
  77  * @start_of_msg_delay: used to set the delay_usecs on the spi_transfer that
  78  *      is sent when we want to turn on CS at the start of a transaction.
  79  * @end_of_msg_delay: used to set the delay_usecs on the spi_transfer that
  80  *      is sent when we want to turn off CS at the end of a transaction.
  81  */
  82 struct cros_ec_spi {
  83         struct spi_device *spi;
  84         s64 last_transfer_ns;
  85         unsigned int start_of_msg_delay;
  86         unsigned int end_of_msg_delay;
  87 };
  88
  89 static void debug_packet(struct device *dev, const char *name, u8 *ptr,
  90                          int len)
  91 {
  92 #ifdef DEBUG
  93         int i;
  94
  95         dev_dbg(dev, "%s: ", name);
  96         for (i = 0; i < len; i++)
  97                 pr_cont(" %02x", ptr[i]);
  98
  99         pr_cont("\n");
 100 #endif
 101 }
 102
 103 static int terminate_request(struct cros_ec_device *ec_dev)
 104 {
 105         struct cros_ec_spi *ec_spi = ec_dev->priv;
 106         struct spi_message msg;
 107         struct spi_transfer trans;
 108         int ret;
 109
 110         /*
 111          * Turn off CS, possibly adding a delay to ensure the rising edge
 112          * doesn't come too soon after the end of the data.
 113          */
 114         spi_message_init(&msg);
 115         memset(&trans, 0, sizeof(trans));
 116         trans.delay_usecs = ec_spi->end_of_msg_delay;
 117         spi_message_add_tail(&trans, &msg);
 118
 119         ret = spi_sync_locked(ec_spi->spi, &msg);
 120
 121         /* Reset end-of-response timer */
 122         ec_spi->last_transfer_ns = ktime_get_ns();
 123         if (ret < 0) {
 124                 dev_err(ec_dev->dev,
 125                         "cs-deassert spi transfer failed: %d\n",
 126                         ret);
 127         }
 128
 129         return ret;
 130 }
 131
 132 /**
 133  * receive_n_bytes - receive n bytes from the EC.
 134  *
 135  * Assumes buf is a pointer into the ec_dev->din buffer
 136  */
 137 static int receive_n_bytes(struct cros_ec_device *ec_dev, u8 *buf, int n)
 138 {
 139         struct cros_ec_spi *ec_spi = ec_dev->priv;
 140         struct spi_transfer trans;
 141         struct spi_message msg;
 142         int ret;
 143
 144         BUG_ON(buf - ec_dev->din + n > ec_dev->din_size);
 145
 146         memset(&trans, 0, sizeof(trans));
 147         trans.cs_change = 1;
 148         trans.rx_buf = buf;
 149         trans.len = n;
 150
 151         spi_message_init(&msg);
 152         spi_message_add_tail(&trans, &msg);
 153         ret = spi_sync_locked(ec_spi->spi, &msg);
 154         if (ret < 0)
 155                 dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
 156
 157         return ret;
 158 }
 159
 160 /**
 161  * cros_ec_spi_receive_packet - Receive a packet from the EC.
 162  *
 163  * This function has two phases: reading the preamble bytes (since if we read
 164  * data from the EC before it is ready to send, we just get preamble) and
 165  * reading the actual message.
 166  *
 167  * The received data is placed into ec_dev->din.
 168  *
 169  * @ec_dev: ChromeOS EC device
 170  * @need_len: Number of message bytes we need to read
 171  */
 172 static int cros_ec_spi_receive_packet(struct cros_ec_device *ec_dev,
 173                                       int need_len)
 174 {
 175         struct ec_host_response *response;
 176         u8 *ptr, *end;
 177         int ret;
 178         unsigned long deadline;
 179         int todo;
 180
 181         BUG_ON(ec_dev->din_size < EC_MSG_PREAMBLE_COUNT);
 182
 183         /* Receive data until we see the header byte */
 184         deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
 185         while (true) {
 186                 unsigned long start_jiffies = jiffies;
 187
 188                 ret = receive_n_bytes(ec_dev,
 189                                       ec_dev->din,
 190                                       EC_MSG_PREAMBLE_COUNT);
 191                 if (ret < 0)
 192                         return ret;
 193
 194                 ptr = ec_dev->din;
 195                 for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
 196                         if (*ptr == EC_SPI_FRAME_START) {
 197                                 dev_dbg(ec_dev->dev, "msg found at %zd\n",
 198                                         ptr - ec_dev->din);
 199                                 break;
 200                         }
 201                 }
 202                 if (ptr != end)
 203                         break;
 204
 205                 /*
 206                  * Use the time at the start of the loop as a timeout.  This
 207                  * gives us one last shot at getting the transfer and is useful
 208                  * in case we got context switched out for a while.
 209                  */
 210                 if (time_after(start_jiffies, deadline)) {
 211                         dev_warn(ec_dev->dev, "EC failed to respond in time\n");
 212                         return -ETIMEDOUT;
 213                 }
 214         }
 215
 216         /*
 217          * ptr now points to the header byte. Copy any valid data to the
 218          * start of our buffer
 219          */
 220         todo = end - ++ptr;
 221         BUG_ON(todo < 0 || todo > ec_dev->din_size);
 222         todo = min(todo, need_len);
 223         memmove(ec_dev->din, ptr, todo);
 224         ptr = ec_dev->din + todo;
 225         dev_dbg(ec_dev->dev, "need %d, got %d bytes from preamble\n",
 226                 need_len, todo);
 227         need_len -= todo;
 228
 229         /* If the entire response struct wasn't read, get the rest of it. */
 230         if (todo < sizeof(*response)) {
 231                 ret = receive_n_bytes(ec_dev, ptr, sizeof(*response) - todo);
 232                 if (ret < 0)
 233                         return -EBADMSG;
 234                 ptr += (sizeof(*response) - todo);
 235                 todo = sizeof(*response);
 236         }
 237
 238         response = (struct ec_host_response *)ec_dev->din;
 239
 240         /* Abort if data_len is too large. */
 241         if (response->data_len > ec_dev->din_size)
 242                 return -EMSGSIZE;
 243
 244         /* Receive data until we have it all */
 245         while (need_len > 0) {
 246                 /*
 247                  * We can't support transfers larger than the SPI FIFO size
 248                  * unless we have DMA. We don't have DMA on the ISP SPI ports
 249                  * for Exynos. We need a way of asking SPI driver for
 250                  * maximum-supported transfer size.
 251                  */
 252                 todo = min(need_len, 256);
 253                 dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
 254                         todo, need_len, ptr - ec_dev->din);
 255
 256                 ret = receive_n_bytes(ec_dev, ptr, todo);
 257                 if (ret < 0)
 258                         return ret;
 259
 260                 ptr += todo;
 261                 need_len -= todo;
 262         }
 263
 264         dev_dbg(ec_dev->dev, "loop done, ptr=%zd\n", ptr - ec_dev->din);
 265
 266         return 0;
 267 }
 268
 269 /**
 270  * cros_ec_spi_receive_response - Receive a response from the EC.
 271  *
 272  * This function has two phases: reading the preamble bytes (since if we read
 273  * data from the EC before it is ready to send, we just get preamble) and
 274  * reading the actual message.
 275  *
 276  * The received data is placed into ec_dev->din.
 277  *
 278  * @ec_dev: ChromeOS EC device
 279  * @need_len: Number of message bytes we need to read
 280  */
 281 static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev,
 282                                         int need_len)
 283 {
 284         u8 *ptr, *end;
 285         int ret;
 286         unsigned long deadline;
 287         int todo;
 288
 289         BUG_ON(ec_dev->din_size < EC_MSG_PREAMBLE_COUNT);
 290
 291         /* Receive data until we see the header byte */
 292         deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
 293         while (true) {
 294                 unsigned long start_jiffies = jiffies;
 295
 296                 ret = receive_n_bytes(ec_dev,
 297                                       ec_dev->din,
 298                                       EC_MSG_PREAMBLE_COUNT);
 299                 if (ret < 0)
 300                         return ret;
 301
 302                 ptr = ec_dev->din;
 303                 for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
 304                         if (*ptr == EC_SPI_FRAME_START) {
 305                                 dev_dbg(ec_dev->dev, "msg found at %zd\n",
 306                                         ptr - ec_dev->din);
 307                                 break;
 308                         }
 309                 }
 310                 if (ptr != end)
 311                         break;
 312
 313                 /*
 314                  * Use the time at the start of the loop as a timeout.  This
 315                  * gives us one last shot at getting the transfer and is useful
 316                  * in case we got context switched out for a while.
 317                  */
 318                 if (time_after(start_jiffies, deadline)) {
 319                         dev_warn(ec_dev->dev, "EC failed to respond in time\n");
 320                         return -ETIMEDOUT;
 321                 }
 322         }
 323
 324         /*
 325          * ptr now points to the header byte. Copy any valid data to the
 326          * start of our buffer
 327          */
 328         todo = end - ++ptr;
 329         BUG_ON(todo < 0 || todo > ec_dev->din_size);
 330         todo = min(todo, need_len);
 331         memmove(ec_dev->din, ptr, todo);
 332         ptr = ec_dev->din + todo;
 333         dev_dbg(ec_dev->dev, "need %d, got %d bytes from preamble\n",
 334                  need_len, todo);
 335         need_len -= todo;
 336
 337         /* Receive data until we have it all */
 338         while (need_len > 0) {
 339                 /*
 340                  * We can't support transfers larger than the SPI FIFO size
 341                  * unless we have DMA. We don't have DMA on the ISP SPI ports
 342                  * for Exynos. We need a way of asking SPI driver for
 343                  * maximum-supported transfer size.
 344                  */
 345                 todo = min(need_len, 256);
 346                 dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
 347                         todo, need_len, ptr - ec_dev->din);
 348
 349                 ret = receive_n_bytes(ec_dev, ptr, todo);
 350                 if (ret < 0)
 351                         return ret;
 352
 353                 debug_packet(ec_dev->dev, "interim", ptr, todo);
 354                 ptr += todo;
 355                 need_len -= todo;
 356         }
 357
 358         dev_dbg(ec_dev->dev, "loop done, ptr=%zd\n", ptr - ec_dev->din);
 359
 360         return 0;
 361 }
 362
 363 /**
 364  * cros_ec_pkt_xfer_spi - Transfer a packet over SPI and receive the reply
 365  *
 366  * @ec_dev: ChromeOS EC device
 367  * @ec_msg: Message to transfer
 368  */
 369 static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
 370                                 struct cros_ec_command *ec_msg)
 371 {
 372         struct ec_host_response *response;
 373         struct cros_ec_spi *ec_spi = ec_dev->priv;
 374         struct spi_transfer trans, trans_delay;
 375         struct spi_message msg;
 376         int i, len;
 377         u8 *ptr;
 378         u8 *rx_buf;
 379         u8 sum;
 380         int ret = 0, final_ret;
 381
 382         len = cros_ec_prepare_tx(ec_dev, ec_msg);
 383         dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
 384
 385         /* If it's too soon to do another transaction, wait */
 386         if (ec_spi->last_transfer_ns) {
 387                 unsigned long delay;    /* The delay completed so far */
 388
 389                 delay = ktime_get_ns() - ec_spi->last_transfer_ns;
 390                 if (delay < EC_SPI_RECOVERY_TIME_NS)
 391                         ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
 392         }
 393
 394         rx_buf = kzalloc(len, GFP_KERNEL);
 395         if (!rx_buf)
 396                 return -ENOMEM;
 397
 398         spi_bus_lock(ec_spi->spi->master);
 399
 400         /*
 401          * Leave a gap between CS assertion and clocking of data to allow the
 402          * EC time to wakeup.
 403          */
 404         spi_message_init(&msg);
 405         if (ec_spi->start_of_msg_delay) {
 406                 memset(&trans_delay, 0, sizeof(trans_delay));
 407                 trans_delay.delay_usecs = ec_spi->start_of_msg_delay;
 408                 spi_message_add_tail(&trans_delay, &msg);
 409         }
 410
 411         /* Transmit phase - send our message */
 412         memset(&trans, 0, sizeof(trans));
 413         trans.tx_buf = ec_dev->dout;
 414         trans.rx_buf = rx_buf;
 415         trans.len = len;
 416         trans.cs_change = 1;
 417         spi_message_add_tail(&trans, &msg);
 418         ret = spi_sync_locked(ec_spi->spi, &msg);
 419
 420         /* Get the response */
 421         if (!ret) {
 422                 /* Verify that EC can process command */
 423                 for (i = 0; i < len; i++) {
 424                         switch (rx_buf[i]) {
 425                         case EC_SPI_PAST_END:
 426                         case EC_SPI_RX_BAD_DATA:
 427                         case EC_SPI_NOT_READY:
 428                                 ret = -EAGAIN;
 429                                 ec_msg->result = EC_RES_IN_PROGRESS;
 430                         default:
 431                                 break;
 432                         }
 433                         if (ret)
 434                                 break;
 435                 }
 436                 if (!ret)
 437                         ret = cros_ec_spi_receive_packet(ec_dev,
 438                                         ec_msg->insize + sizeof(*response));
 439         } else {
 440                 dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
 441         }
 442
 443         final_ret = terminate_request(ec_dev);
 444
 445         spi_bus_unlock(ec_spi->spi->master);
 446
 447         if (!ret)
 448                 ret = final_ret;
 449         if (ret < 0)
 450                 goto exit;
 451
 452         ptr = ec_dev->din;
 453
 454         /* check response error code */
 455         response = (struct ec_host_response *)ptr;
 456         ec_msg->result = response->result;
 457
 458         ret = cros_ec_check_result(ec_dev, ec_msg);
 459         if (ret)
 460                 goto exit;
 461
 462         len = response->data_len;
 463         sum = 0;
 464         if (len > ec_msg->insize) {
 465                 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
 466                         len, ec_msg->insize);
 467                 ret = -EMSGSIZE;
 468                 goto exit;
 469         }
 470
 471         for (i = 0; i < sizeof(*response); i++)
 472                 sum += ptr[i];
 473
 474         /* copy response packet payload and compute checksum */
 475         memcpy(ec_msg->data, ptr + sizeof(*response), len);
 476         for (i = 0; i < len; i++)
 477                 sum += ec_msg->data[i];
 478
 479         if (sum) {
 480                 dev_err(ec_dev->dev,
 481                         "bad packet checksum, calculated %x\n",
 482                         sum);
 483                 ret = -EBADMSG;
 484                 goto exit;
 485         }
 486
 487         ret = len;
 488 exit:
 489         kfree(rx_buf);
 490         if (ec_msg->command == EC_CMD_REBOOT_EC)
 491                 msleep(EC_REBOOT_DELAY_MS);
 492
 493         return ret;
 494 }
 495
 496 /**
 497  * cros_ec_cmd_xfer_spi - Transfer a message over SPI and receive the reply
 498  *
 499  * @ec_dev: ChromeOS EC device
 500  * @ec_msg: Message to transfer
 501  */
 502 static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
 503                                 struct cros_ec_command *ec_msg)
 504 {
 505         struct cros_ec_spi *ec_spi = ec_dev->priv;
 506         struct spi_transfer trans;
 507         struct spi_message msg;
 508         int i, len;
 509         u8 *ptr;
 510         u8 *rx_buf;
 511         int sum;
 512         int ret = 0, final_ret;
 513
 514         len = cros_ec_prepare_tx(ec_dev, ec_msg);
 515         dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
 516
 517         /* If it's too soon to do another transaction, wait */
 518         if (ec_spi->last_transfer_ns) {
 519                 unsigned long delay;    /* The delay completed so far */
 520
 521                 delay = ktime_get_ns() - ec_spi->last_transfer_ns;
 522                 if (delay < EC_SPI_RECOVERY_TIME_NS)
 523                         ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
 524         }
 525
 526         rx_buf = kzalloc(len, GFP_KERNEL);
 527         if (!rx_buf)
 528                 return -ENOMEM;
 529
 530         spi_bus_lock(ec_spi->spi->master);
 531
 532         /* Transmit phase - send our message */
 533         debug_packet(ec_dev->dev, "out", ec_dev->dout, len);
 534         memset(&trans, 0, sizeof(trans));
 535         trans.tx_buf = ec_dev->dout;
 536         trans.rx_buf = rx_buf;
 537         trans.len = len;
 538         trans.cs_change = 1;
 539         spi_message_init(&msg);
 540         spi_message_add_tail(&trans, &msg);
 541         ret = spi_sync_locked(ec_spi->spi, &msg);
 542
 543         /* Get the response */
 544         if (!ret) {
 545                 /* Verify that EC can process command */
 546                 for (i = 0; i < len; i++) {
 547                         switch (rx_buf[i]) {
 548                         case EC_SPI_PAST_END:
 549                         case EC_SPI_RX_BAD_DATA:
 550                         case EC_SPI_NOT_READY:
 551                                 ret = -EAGAIN;
 552                                 ec_msg->result = EC_RES_IN_PROGRESS;
 553                         default:
 554                                 break;
 555                         }
 556                         if (ret)
 557                                 break;
 558                 }
 559                 if (!ret)
 560                         ret = cros_ec_spi_receive_response(ec_dev,
 561                                         ec_msg->insize + EC_MSG_TX_PROTO_BYTES);
 562         } else {
 563                 dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
 564         }
 565
 566         final_ret = terminate_request(ec_dev);
 567
 568         spi_bus_unlock(ec_spi->spi->master);
 569
 570         if (!ret)
 571                 ret = final_ret;
 572         if (ret < 0)
 573                 goto exit;
 574
 575         ptr = ec_dev->din;
 576
 577         /* check response error code */
 578         ec_msg->result = ptr[0];
 579         ret = cros_ec_check_result(ec_dev, ec_msg);
 580         if (ret)
 581                 goto exit;
 582
 583         len = ptr[1];
 584         sum = ptr[0] + ptr[1];
 585         if (len > ec_msg->insize) {
 586                 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
 587                         len, ec_msg->insize);
 588                 ret = -ENOSPC;
 589                 goto exit;
 590         }
 591
 592         /* copy response packet payload and compute checksum */
 593         for (i = 0; i < len; i++) {
 594                 sum += ptr[i + 2];
 595                 if (ec_msg->insize)
 596                         ec_msg->data[i] = ptr[i + 2];
 597         }
 598         sum &= 0xff;
 599
 600         debug_packet(ec_dev->dev, "in", ptr, len + 3);
 601
 602         if (sum != ptr[len + 2]) {
 603                 dev_err(ec_dev->dev,
 604                         "bad packet checksum, expected %02x, got %02x\n",
 605                         sum, ptr[len + 2]);
 606                 ret = -EBADMSG;
 607                 goto exit;
 608         }
 609
 610         ret = len;
 611 exit:
 612         kfree(rx_buf);
 613         if (ec_msg->command == EC_CMD_REBOOT_EC)
 614                 msleep(EC_REBOOT_DELAY_MS);
 615
 616         return ret;
 617 }
 618
 619 static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev)
 620 {
 621         struct device_node *np = dev->of_node;
 622         u32 val;
 623         int ret;
 624
 625         ret = of_property_read_u32(np, "google,cros-ec-spi-pre-delay", &val);
 626         if (!ret)
 627                 ec_spi->start_of_msg_delay = val;
 628
 629         ret = of_property_read_u32(np, "google,cros-ec-spi-msg-delay", &val);
 630         if (!ret)
 631                 ec_spi->end_of_msg_delay = val;
 632 }
 633
 634 static int cros_ec_spi_probe(struct spi_device *spi)
 635 {
 636         struct device *dev = &spi->dev;
 637         struct cros_ec_device *ec_dev;
 638         struct cros_ec_spi *ec_spi;
 639         int err;
 640
 641         spi->bits_per_word = 8;
 642         spi->mode = SPI_MODE_0;
 643         err = spi_setup(spi);
 644         if (err < 0)
 645                 return err;
 646
 647         ec_spi = devm_kzalloc(dev, sizeof(*ec_spi), GFP_KERNEL);
 648         if (ec_spi == NULL)
 649                 return -ENOMEM;
 650         ec_spi->spi = spi;
 651         ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
 652         if (!ec_dev)
 653                 return -ENOMEM;
 654
 655         /* Check for any DT properties */
 656         cros_ec_spi_dt_probe(ec_spi, dev);
 657
 658         spi_set_drvdata(spi, ec_dev);
 659         ec_dev->dev = dev;
 660         ec_dev->priv = ec_spi;
 661         ec_dev->irq = spi->irq;
 662         ec_dev->cmd_xfer = cros_ec_cmd_xfer_spi;
 663         ec_dev->pkt_xfer = cros_ec_pkt_xfer_spi;
 664         ec_dev->phys_name = dev_name(&ec_spi->spi->dev);
 665         ec_dev->din_size = EC_MSG_PREAMBLE_COUNT +
 666                            sizeof(struct ec_host_response) +
 667                            sizeof(struct ec_response_get_protocol_info);
 668         ec_dev->dout_size = sizeof(struct ec_host_request);
 669
 670
 671         err = cros_ec_register(ec_dev);
 672         if (err) {
 673                 dev_err(dev, "cannot register EC\n");
 674                 return err;
 675         }
 676
 677         device_init_wakeup(&spi->dev, true);
 678
 679         return 0;
 680 }
 681
 682 static int cros_ec_spi_remove(struct spi_device *spi)
 683 {
 684         struct cros_ec_device *ec_dev;
 685
 686         ec_dev = spi_get_drvdata(spi);
 687         cros_ec_remove(ec_dev);
 688
 689         return 0;
 690 }
 691
 692 #ifdef CONFIG_PM_SLEEP
 693 static int cros_ec_spi_suspend(struct device *dev)
 694 {
 695         struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
 696
 697         return cros_ec_suspend(ec_dev);
 698 }
 699
 700 static int cros_ec_spi_resume(struct device *dev)
 701 {
 702         struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
 703
 704         return cros_ec_resume(ec_dev);
 705 }
 706 #endif
 707
 708 static SIMPLE_DEV_PM_OPS(cros_ec_spi_pm_ops, cros_ec_spi_suspend,
 709                          cros_ec_spi_resume);
 710
 711 static const struct of_device_id cros_ec_spi_of_match[] = {
 712         { .compatible = "google,cros-ec-spi", },
 713         { /* sentinel */ },
 714 };
 715 MODULE_DEVICE_TABLE(of, cros_ec_spi_of_match);
 716
 717 static const struct spi_device_id cros_ec_spi_id[] = {
 718         { "cros-ec-spi", 0 },
 719         { }
 720 };
 721 MODULE_DEVICE_TABLE(spi, cros_ec_spi_id);
 722
 723 static struct spi_driver cros_ec_driver_spi = {
 724         .driver = {
 725                 .name   = "cros-ec-spi",
 726                 .of_match_table = of_match_ptr(cros_ec_spi_of_match),
 727                 .pm     = &cros_ec_spi_pm_ops,
 728         },
 729         .probe          = cros_ec_spi_probe,
 730         .remove         = cros_ec_spi_remove,
 731         .id_table       = cros_ec_spi_id,
 732 };
 733
 734 module_spi_driver(cros_ec_driver_spi);
 735
 736 MODULE_LICENSE("GPL v2");
 737 MODULE_DESCRIPTION("ChromeOS EC multi function device (SPI)");