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.
  76  * @start_of_msg_delay: used to set the delay_usecs on the spi_transfer that
  77  *      is sent when we want to turn on CS at the start of a transaction.
  78  * @end_of_msg_delay: used to set the delay_usecs on the spi_transfer that
  79  *      is sent when we want to turn off CS at the end of a transaction.
  80  */
  81 struct cros_ec_spi {
  82         struct spi_device *spi;
  83         s64 last_transfer_ns;
  84         unsigned int start_of_msg_delay;
  85         unsigned int end_of_msg_delay;
  86 };
  87
  88 static void debug_packet(struct device *dev, const char *name, u8 *ptr,
  89                          int len)
  90 {
  91 #ifdef DEBUG
  92         int i;
  93
  94         dev_dbg(dev, "%s: ", name);
  95         for (i = 0; i < len; i++)
  96                 pr_cont(" %02x", ptr[i]);
  97
  98         pr_cont("\n");
  99 #endif
 100 }
 101
 102 static int terminate_request(struct cros_ec_device *ec_dev)
 103 {
 104         struct cros_ec_spi *ec_spi = ec_dev->priv;
 105         struct spi_message msg;
 106         struct spi_transfer trans;
 107         int ret;
 108
 109         /*
 110          * Turn off CS, possibly adding a delay to ensure the rising edge
 111          * doesn't come too soon after the end of the data.
 112          */
 113         spi_message_init(&msg);
 114         memset(&trans, 0, sizeof(trans));
 115         trans.delay_usecs = ec_spi->end_of_msg_delay;
 116         spi_message_add_tail(&trans, &msg);
 117
 118         ret = spi_sync_locked(ec_spi->spi, &msg);
 119
 120         /* Reset end-of-response timer */
 121         ec_spi->last_transfer_ns = ktime_get_ns();
 122         if (ret < 0) {
 123                 dev_err(ec_dev->dev,
 124                         "cs-deassert spi transfer failed: %d\n",
 125                         ret);
 126         }
 127
 128         return ret;
 129 }
 130
 131 /**
 132  * receive_n_bytes - receive n bytes from the EC.
 133  *
 134  * Assumes buf is a pointer into the ec_dev->din buffer
 135  */
 136 static int receive_n_bytes(struct cros_ec_device *ec_dev, u8 *buf, int n)
 137 {
 138         struct cros_ec_spi *ec_spi = ec_dev->priv;
 139         struct spi_transfer trans;
 140         struct spi_message msg;
 141         int ret;
 142
 143         BUG_ON(buf - ec_dev->din + n > ec_dev->din_size);
 144
 145         memset(&trans, 0, sizeof(trans));
 146         trans.cs_change = 1;
 147         trans.rx_buf = buf;
 148         trans.len = n;
 149
 150         spi_message_init(&msg);
 151         spi_message_add_tail(&trans, &msg);
 152         ret = spi_sync_locked(ec_spi->spi, &msg);
 153         if (ret < 0)
 154                 dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
 155
 156         return ret;
 157 }
 158
 159 /**
 160  * cros_ec_spi_receive_packet - Receive a packet from the EC.
 161  *
 162  * This function has two phases: reading the preamble bytes (since if we read
 163  * data from the EC before it is ready to send, we just get preamble) and
 164  * reading the actual message.
 165  *
 166  * The received data is placed into ec_dev->din.
 167  *
 168  * @ec_dev: ChromeOS EC device
 169  * @need_len: Number of message bytes we need to read
 170  */
 171 static int cros_ec_spi_receive_packet(struct cros_ec_device *ec_dev,
 172                                       int need_len)
 173 {
 174         struct ec_host_response *response;
 175         u8 *ptr, *end;
 176         int ret;
 177         unsigned long deadline;
 178         int todo;
 179
 180         BUG_ON(ec_dev->din_size < EC_MSG_PREAMBLE_COUNT);
 181
 182         /* Receive data until we see the header byte */
 183         deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
 184         while (true) {
 185                 unsigned long start_jiffies = jiffies;
 186
 187                 ret = receive_n_bytes(ec_dev,
 188                                       ec_dev->din,
 189                                       EC_MSG_PREAMBLE_COUNT);
 190                 if (ret < 0)
 191                         return ret;
 192
 193                 ptr = ec_dev->din;
 194                 for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
 195                         if (*ptr == EC_SPI_FRAME_START) {
 196                                 dev_dbg(ec_dev->dev, "msg found at %zd\n",
 197                                         ptr - ec_dev->din);
 198                                 break;
 199                         }
 200                 }
 201                 if (ptr != end)
 202                         break;
 203
 204                 /*
 205                  * Use the time at the start of the loop as a timeout.  This
 206                  * gives us one last shot at getting the transfer and is useful
 207                  * in case we got context switched out for a while.
 208                  */
 209                 if (time_after(start_jiffies, deadline)) {
 210                         dev_warn(ec_dev->dev, "EC failed to respond in time\n");
 211                         return -ETIMEDOUT;
 212                 }
 213         }
 214
 215         /*
 216          * ptr now points to the header byte. Copy any valid data to the
 217          * start of our buffer
 218          */
 219         todo = end - ++ptr;
 220         BUG_ON(todo < 0 || todo > ec_dev->din_size);
 221         todo = min(todo, need_len);
 222         memmove(ec_dev->din, ptr, todo);
 223         ptr = ec_dev->din + todo;
 224         dev_dbg(ec_dev->dev, "need %d, got %d bytes from preamble\n",
 225                 need_len, todo);
 226         need_len -= todo;
 227
 228         /* If the entire response struct wasn't read, get the rest of it. */
 229         if (todo < sizeof(*response)) {
 230                 ret = receive_n_bytes(ec_dev, ptr, sizeof(*response) - todo);
 231                 if (ret < 0)
 232                         return -EBADMSG;
 233                 ptr += (sizeof(*response) - todo);
 234                 todo = sizeof(*response);
 235         }
 236
 237         response = (struct ec_host_response *)ec_dev->din;
 238
 239         /* Abort if data_len is too large. */
 240         if (response->data_len > ec_dev->din_size)
 241                 return -EMSGSIZE;
 242
 243         /* Receive data until we have it all */
 244         while (need_len > 0) {
 245                 /*
 246                  * We can't support transfers larger than the SPI FIFO size
 247                  * unless we have DMA. We don't have DMA on the ISP SPI ports
 248                  * for Exynos. We need a way of asking SPI driver for
 249                  * maximum-supported transfer size.
 250                  */
 251                 todo = min(need_len, 256);
 252                 dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
 253                         todo, need_len, ptr - ec_dev->din);
 254
 255                 ret = receive_n_bytes(ec_dev, ptr, todo);
 256                 if (ret < 0)
 257                         return ret;
 258
 259                 ptr += todo;
 260                 need_len -= todo;
 261         }
 262
 263         dev_dbg(ec_dev->dev, "loop done, ptr=%zd\n", ptr - ec_dev->din);
 264
 265         return 0;
 266 }
 267
 268 /**
 269  * cros_ec_spi_receive_response - Receive a response from the EC.
 270  *
 271  * This function has two phases: reading the preamble bytes (since if we read
 272  * data from the EC before it is ready to send, we just get preamble) and
 273  * reading the actual message.
 274  *
 275  * The received data is placed into ec_dev->din.
 276  *
 277  * @ec_dev: ChromeOS EC device
 278  * @need_len: Number of message bytes we need to read
 279  */
 280 static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev,
 281                                         int need_len)
 282 {
 283         u8 *ptr, *end;
 284         int ret;
 285         unsigned long deadline;
 286         int todo;
 287
 288         BUG_ON(ec_dev->din_size < EC_MSG_PREAMBLE_COUNT);
 289
 290         /* Receive data until we see the header byte */
 291         deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
 292         while (true) {
 293                 unsigned long start_jiffies = jiffies;
 294
 295                 ret = receive_n_bytes(ec_dev,
 296                                       ec_dev->din,
 297                                       EC_MSG_PREAMBLE_COUNT);
 298                 if (ret < 0)
 299                         return ret;
 300
 301                 ptr = ec_dev->din;
 302                 for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
 303                         if (*ptr == EC_SPI_FRAME_START) {
 304                                 dev_dbg(ec_dev->dev, "msg found at %zd\n",
 305                                         ptr - ec_dev->din);
 306                                 break;
 307                         }
 308                 }
 309                 if (ptr != end)
 310                         break;
 311
 312                 /*
 313                  * Use the time at the start of the loop as a timeout.  This
 314                  * gives us one last shot at getting the transfer and is useful
 315                  * in case we got context switched out for a while.
 316                  */
 317                 if (time_after(start_jiffies, deadline)) {
 318                         dev_warn(ec_dev->dev, "EC failed to respond in time\n");
 319                         return -ETIMEDOUT;
 320                 }
 321         }
 322
 323         /*
 324          * ptr now points to the header byte. Copy any valid data to the
 325          * start of our buffer
 326          */
 327         todo = end - ++ptr;
 328         BUG_ON(todo < 0 || todo > ec_dev->din_size);
 329         todo = min(todo, need_len);
 330         memmove(ec_dev->din, ptr, todo);
 331         ptr = ec_dev->din + todo;
 332         dev_dbg(ec_dev->dev, "need %d, got %d bytes from preamble\n",
 333                  need_len, todo);
 334         need_len -= todo;
 335
 336         /* Receive data until we have it all */
 337         while (need_len > 0) {
 338                 /*
 339                  * We can't support transfers larger than the SPI FIFO size
 340                  * unless we have DMA. We don't have DMA on the ISP SPI ports
 341                  * for Exynos. We need a way of asking SPI driver for
 342                  * maximum-supported transfer size.
 343                  */
 344                 todo = min(need_len, 256);
 345                 dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
 346                         todo, need_len, ptr - ec_dev->din);
 347
 348                 ret = receive_n_bytes(ec_dev, ptr, todo);
 349                 if (ret < 0)
 350                         return ret;
 351
 352                 debug_packet(ec_dev->dev, "interim", ptr, todo);
 353                 ptr += todo;
 354                 need_len -= todo;
 355         }
 356
 357         dev_dbg(ec_dev->dev, "loop done, ptr=%zd\n", ptr - ec_dev->din);
 358
 359         return 0;
 360 }
 361
 362 /**
 363  * cros_ec_pkt_xfer_spi - Transfer a packet over SPI and receive the reply
 364  *
 365  * @ec_dev: ChromeOS EC device
 366  * @ec_msg: Message to transfer
 367  */
 368 static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
 369                                 struct cros_ec_command *ec_msg)
 370 {
 371         struct ec_host_response *response;
 372         struct cros_ec_spi *ec_spi = ec_dev->priv;
 373         struct spi_transfer trans, trans_delay;
 374         struct spi_message msg;
 375         int i, len;
 376         u8 *ptr;
 377         u8 *rx_buf;
 378         u8 sum;
 379         u8 rx_byte;
 380         int ret = 0, final_ret;
 381         unsigned long delay;
 382
 383         len = cros_ec_prepare_tx(ec_dev, ec_msg);
 384         dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
 385
 386         /* If it's too soon to do another transaction, wait */
 387         delay = ktime_get_ns() - ec_spi->last_transfer_ns;
 388         if (delay < EC_SPI_RECOVERY_TIME_NS)
 389                 ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
 390
 391         rx_buf = kzalloc(len, GFP_KERNEL);
 392         if (!rx_buf)
 393                 return -ENOMEM;
 394
 395         spi_bus_lock(ec_spi->spi->master);
 396
 397         /*
 398          * Leave a gap between CS assertion and clocking of data to allow the
 399          * EC time to wakeup.
 400          */
 401         spi_message_init(&msg);
 402         if (ec_spi->start_of_msg_delay) {
 403                 memset(&trans_delay, 0, sizeof(trans_delay));
 404                 trans_delay.delay_usecs = ec_spi->start_of_msg_delay;
 405                 spi_message_add_tail(&trans_delay, &msg);
 406         }
 407
 408         /* Transmit phase - send our message */
 409         memset(&trans, 0, sizeof(trans));
 410         trans.tx_buf = ec_dev->dout;
 411         trans.rx_buf = rx_buf;
 412         trans.len = len;
 413         trans.cs_change = 1;
 414         spi_message_add_tail(&trans, &msg);
 415         ret = spi_sync_locked(ec_spi->spi, &msg);
 416
 417         /* Get the response */
 418         if (!ret) {
 419                 /* Verify that EC can process command */
 420                 for (i = 0; i < len; i++) {
 421                         rx_byte = rx_buf[i];
 422                         /*
 423                          * Seeing the PAST_END, RX_BAD_DATA, or NOT_READY
 424                          * markers are all signs that the EC didn't fully
 425                          * receive our command. e.g., if the EC is flashing
 426                          * itself, it can't respond to any commands and instead
 427                          * clocks out EC_SPI_PAST_END from its SPI hardware
 428                          * buffer. Similar occurrences can happen if the AP is
 429                          * too slow to clock out data after asserting CS -- the
 430                          * EC will abort and fill its buffer with
 431                          * EC_SPI_RX_BAD_DATA.
 432                          *
 433                          * In all cases, these errors should be safe to retry.
 434                          * Report -EAGAIN and let the caller decide what to do
 435                          * about that.
 436                          */
 437                         if (rx_byte == EC_SPI_PAST_END  ||
 438                             rx_byte == EC_SPI_RX_BAD_DATA ||
 439                             rx_byte == EC_SPI_NOT_READY) {
 440                                 ret = -EAGAIN;
 441                                 break;
 442                         }
 443                 }
 444         }
 445
 446         if (!ret)
 447                 ret = cros_ec_spi_receive_packet(ec_dev,
 448                                 ec_msg->insize + sizeof(*response));
 449         else if (ret != -EAGAIN)
 450                 dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
 451
 452         final_ret = terminate_request(ec_dev);
 453
 454         spi_bus_unlock(ec_spi->spi->master);
 455
 456         if (!ret)
 457                 ret = final_ret;
 458         if (ret < 0)
 459                 goto exit;
 460
 461         ptr = ec_dev->din;
 462
 463         /* check response error code */
 464         response = (struct ec_host_response *)ptr;
 465         ec_msg->result = response->result;
 466
 467         ret = cros_ec_check_result(ec_dev, ec_msg);
 468         if (ret)
 469                 goto exit;
 470
 471         len = response->data_len;
 472         sum = 0;
 473         if (len > ec_msg->insize) {
 474                 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
 475                         len, ec_msg->insize);
 476                 ret = -EMSGSIZE;
 477                 goto exit;
 478         }
 479
 480         for (i = 0; i < sizeof(*response); i++)
 481                 sum += ptr[i];
 482
 483         /* copy response packet payload and compute checksum */
 484         memcpy(ec_msg->data, ptr + sizeof(*response), len);
 485         for (i = 0; i < len; i++)
 486                 sum += ec_msg->data[i];
 487
 488         if (sum) {
 489                 dev_err(ec_dev->dev,
 490                         "bad packet checksum, calculated %x\n",
 491                         sum);
 492                 ret = -EBADMSG;
 493                 goto exit;
 494         }
 495
 496         ret = len;
 497 exit:
 498         kfree(rx_buf);
 499         if (ec_msg->command == EC_CMD_REBOOT_EC)
 500                 msleep(EC_REBOOT_DELAY_MS);
 501
 502         return ret;
 503 }
 504
 505 /**
 506  * cros_ec_cmd_xfer_spi - Transfer a message over SPI and receive the reply
 507  *
 508  * @ec_dev: ChromeOS EC device
 509  * @ec_msg: Message to transfer
 510  */
 511 static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
 512                                 struct cros_ec_command *ec_msg)
 513 {
 514         struct cros_ec_spi *ec_spi = ec_dev->priv;
 515         struct spi_transfer trans;
 516         struct spi_message msg;
 517         int i, len;
 518         u8 *ptr;
 519         u8 *rx_buf;
 520         u8 rx_byte;
 521         int sum;
 522         int ret = 0, final_ret;
 523         unsigned long delay;
 524
 525         len = cros_ec_prepare_tx(ec_dev, ec_msg);
 526         dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
 527
 528         /* If it's too soon to do another transaction, wait */
 529         delay = ktime_get_ns() - ec_spi->last_transfer_ns;
 530         if (delay < EC_SPI_RECOVERY_TIME_NS)
 531                 ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
 532
 533         rx_buf = kzalloc(len, GFP_KERNEL);
 534         if (!rx_buf)
 535                 return -ENOMEM;
 536
 537         spi_bus_lock(ec_spi->spi->master);
 538
 539         /* Transmit phase - send our message */
 540         debug_packet(ec_dev->dev, "out", ec_dev->dout, len);
 541         memset(&trans, 0, sizeof(trans));
 542         trans.tx_buf = ec_dev->dout;
 543         trans.rx_buf = rx_buf;
 544         trans.len = len;
 545         trans.cs_change = 1;
 546         spi_message_init(&msg);
 547         spi_message_add_tail(&trans, &msg);
 548         ret = spi_sync_locked(ec_spi->spi, &msg);
 549
 550         /* Get the response */
 551         if (!ret) {
 552                 /* Verify that EC can process command */
 553                 for (i = 0; i < len; i++) {
 554                         rx_byte = rx_buf[i];
 555                         /* See comments in cros_ec_pkt_xfer_spi() */
 556                         if (rx_byte == EC_SPI_PAST_END  ||
 557                             rx_byte == EC_SPI_RX_BAD_DATA ||
 558                             rx_byte == EC_SPI_NOT_READY) {
 559                                 ret = -EAGAIN;
 560                                 break;
 561                         }
 562                 }
 563         }
 564
 565         if (!ret)
 566                 ret = cros_ec_spi_receive_response(ec_dev,
 567                                 ec_msg->insize + EC_MSG_TX_PROTO_BYTES);
 568         else if (ret != -EAGAIN)
 569                 dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
 570
 571         final_ret = terminate_request(ec_dev);
 572
 573         spi_bus_unlock(ec_spi->spi->master);
 574
 575         if (!ret)
 576                 ret = final_ret;
 577         if (ret < 0)
 578                 goto exit;
 579
 580         ptr = ec_dev->din;
 581
 582         /* check response error code */
 583         ec_msg->result = ptr[0];
 584         ret = cros_ec_check_result(ec_dev, ec_msg);
 585         if (ret)
 586                 goto exit;
 587
 588         len = ptr[1];
 589         sum = ptr[0] + ptr[1];
 590         if (len > ec_msg->insize) {
 591                 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
 592                         len, ec_msg->insize);
 593                 ret = -ENOSPC;
 594                 goto exit;
 595         }
 596
 597         /* copy response packet payload and compute checksum */
 598         for (i = 0; i < len; i++) {
 599                 sum += ptr[i + 2];
 600                 if (ec_msg->insize)
 601                         ec_msg->data[i] = ptr[i + 2];
 602         }
 603         sum &= 0xff;
 604
 605         debug_packet(ec_dev->dev, "in", ptr, len + 3);
 606
 607         if (sum != ptr[len + 2]) {
 608                 dev_err(ec_dev->dev,
 609                         "bad packet checksum, expected %02x, got %02x\n",
 610                         sum, ptr[len + 2]);
 611                 ret = -EBADMSG;
 612                 goto exit;
 613         }
 614
 615         ret = len;
 616 exit:
 617         kfree(rx_buf);
 618         if (ec_msg->command == EC_CMD_REBOOT_EC)
 619                 msleep(EC_REBOOT_DELAY_MS);
 620
 621         return ret;
 622 }
 623
 624 static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev)
 625 {
 626         struct device_node *np = dev->of_node;
 627         u32 val;
 628         int ret;
 629
 630         ret = of_property_read_u32(np, "google,cros-ec-spi-pre-delay", &val);
 631         if (!ret)
 632                 ec_spi->start_of_msg_delay = val;
 633
 634         ret = of_property_read_u32(np, "google,cros-ec-spi-msg-delay", &val);
 635         if (!ret)
 636                 ec_spi->end_of_msg_delay = val;
 637 }
 638
 639 static int cros_ec_spi_probe(struct spi_device *spi)
 640 {
 641         struct device *dev = &spi->dev;
 642         struct cros_ec_device *ec_dev;
 643         struct cros_ec_spi *ec_spi;
 644         int err;
 645
 646         spi->bits_per_word = 8;
 647         spi->mode = SPI_MODE_0;
 648         err = spi_setup(spi);
 649         if (err < 0)
 650                 return err;
 651
 652         ec_spi = devm_kzalloc(dev, sizeof(*ec_spi), GFP_KERNEL);
 653         if (ec_spi == NULL)
 654                 return -ENOMEM;
 655         ec_spi->spi = spi;
 656         ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
 657         if (!ec_dev)
 658                 return -ENOMEM;
 659
 660         /* Check for any DT properties */
 661         cros_ec_spi_dt_probe(ec_spi, dev);
 662
 663         spi_set_drvdata(spi, ec_dev);
 664         ec_dev->dev = dev;
 665         ec_dev->priv = ec_spi;
 666         ec_dev->irq = spi->irq;
 667         ec_dev->cmd_xfer = cros_ec_cmd_xfer_spi;
 668         ec_dev->pkt_xfer = cros_ec_pkt_xfer_spi;
 669         ec_dev->phys_name = dev_name(&ec_spi->spi->dev);
 670         ec_dev->din_size = EC_MSG_PREAMBLE_COUNT +
 671                            sizeof(struct ec_host_response) +
 672                            sizeof(struct ec_response_get_protocol_info);
 673         ec_dev->dout_size = sizeof(struct ec_host_request);
 674
 675         ec_spi->last_transfer_ns = ktime_get_ns();
 676
 677         err = cros_ec_register(ec_dev);
 678         if (err) {
 679                 dev_err(dev, "cannot register EC\n");
 680                 return err;
 681         }
 682
 683         device_init_wakeup(&spi->dev, true);
 684
 685         return 0;
 686 }
 687
 688 static int cros_ec_spi_remove(struct spi_device *spi)
 689 {
 690         struct cros_ec_device *ec_dev;
 691
 692         ec_dev = spi_get_drvdata(spi);
 693         cros_ec_remove(ec_dev);
 694
 695         return 0;
 696 }
 697
 698 #ifdef CONFIG_PM_SLEEP
 699 static int cros_ec_spi_suspend(struct device *dev)
 700 {
 701         struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
 702
 703         return cros_ec_suspend(ec_dev);
 704 }
 705
 706 static int cros_ec_spi_resume(struct device *dev)
 707 {
 708         struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
 709
 710         return cros_ec_resume(ec_dev);
 711 }
 712 #endif
 713
 714 static SIMPLE_DEV_PM_OPS(cros_ec_spi_pm_ops, cros_ec_spi_suspend,
 715                          cros_ec_spi_resume);
 716
 717 static const struct of_device_id cros_ec_spi_of_match[] = {
 718         { .compatible = "google,cros-ec-spi", },
 719         { /* sentinel */ },
 720 };
 721 MODULE_DEVICE_TABLE(of, cros_ec_spi_of_match);
 722
 723 static const struct spi_device_id cros_ec_spi_id[] = {
 724         { "cros-ec-spi", 0 },
 725         { }
 726 };
 727 MODULE_DEVICE_TABLE(spi, cros_ec_spi_id);
 728
 729 static struct spi_driver cros_ec_driver_spi = {
 730         .driver = {
 731                 .name   = "cros-ec-spi",
 732                 .of_match_table = of_match_ptr(cros_ec_spi_of_match),
 733                 .pm     = &cros_ec_spi_pm_ops,
 734         },
 735         .probe          = cros_ec_spi_probe,
 736         .remove         = cros_ec_spi_remove,
 737         .id_table       = cros_ec_spi_id,
 738 };
 739
 740 module_spi_driver(cros_ec_driver_spi);
 741
 742 MODULE_LICENSE("GPL v2");
 743 MODULE_DESCRIPTION("ChromeOS EC multi function device (SPI)");