aboutsummaryrefslogtreecommitdiff
path: root/drivers/mfd/cros_ec_spi.c
blob: 30a296b4e748c05abf038c2f90b1b8e172c4770e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
/*
 * ChromeOS EC multi-function device (SPI)
 *
 * Copyright (C) 2012 Google, Inc
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>


/* The header byte, which follows the preamble */
#define EC_MSG_HEADER			0xec

/*
 * Number of EC preamble bytes we read at a time. Since it takes
 * about 400-500us for the EC to respond there is not a lot of
 * point in tuning this. If the EC could respond faster then
 * we could increase this so that might expect the preamble and
 * message to occur in a single transaction. However, the maximum
 * SPI transfer size is 256 bytes, so at 5MHz we need a response
 * time of perhaps <320us (200 bytes / 1600 bits).
 */
#define EC_MSG_PREAMBLE_COUNT		32

/*
 * Allow for a long time for the EC to respond.  We support i2c
 * tunneling and support fairly long messages for the tunnel (249
 * bytes long at the moment).  If we're talking to a 100 kHz device
 * on the other end and need to transfer ~256 bytes, then we need:
 *  10 us/bit * ~10 bits/byte * ~256 bytes = ~25ms
 *
 * We'll wait 4 times that to handle clock stretching and other
 * paranoia.
 *
 * It's pretty unlikely that we'll really see a 249 byte tunnel in
 * anything other than testing.  If this was more common we might
 * consider having slow commands like this require a GET_STATUS
 * wait loop.  The 'flash write' command would be another candidate
 * for this, clocking in at 2-3ms.
 */
#define EC_MSG_DEADLINE_MS		100

/*
  * Time between raising the SPI chip select (for the end of a
  * transaction) and dropping it again (for the next transaction).
  * If we go too fast, the EC will miss the transaction. We know that we
  * need at least 70 us with the 16 MHz STM32 EC, so go with 200 us to be
  * safe.
  */
#define EC_SPI_RECOVERY_TIME_NS	(200 * 1000)

/**
 * struct cros_ec_spi - information about a SPI-connected EC
 *
 * @spi: SPI device we are connected to
 * @last_transfer_ns: time that we last finished a transfer, or 0 if there
 *	if no record
 * @start_of_msg_delay: used to set the delay_usecs on the spi_transfer that
 *      is sent when we want to turn on CS at the start of a transaction.
 * @end_of_msg_delay: used to set the delay_usecs on the spi_transfer that
 *      is sent when we want to turn off CS at the end of a transaction.
 */
struct cros_ec_spi {
	struct spi_device *spi;
	s64 last_transfer_ns;
	unsigned int start_of_msg_delay;
	unsigned int end_of_msg_delay;
};

static void debug_packet(struct device *dev, const char *name, u8 *ptr,
			 int len)
{
#ifdef DEBUG
	int i;

	dev_dbg(dev, "%s: ", name);
	for (i = 0; i < len; i++)
		pr_cont(" %02x", ptr[i]);

	pr_cont("\n");
#endif
}

static int terminate_request(struct cros_ec_device *ec_dev)
{
	struct cros_ec_spi *ec_spi = ec_dev->priv;
	struct spi_message msg;
	struct spi_transfer trans;
	int ret;

	/*
	 * Turn off CS, possibly adding a delay to ensure the rising edge
	 * doesn't come too soon after the end of the data.
	 */
	spi_message_init(&msg);
	memset(&trans, 0, sizeof(trans));
	trans.delay_usecs = ec_spi->end_of_msg_delay;
	spi_message_add_tail(&trans, &msg);

	ret = spi_sync(ec_spi->spi, &msg);

	/* Reset end-of-response timer */
	ec_spi->last_transfer_ns = ktime_get_ns();
	if (ret < 0) {
		dev_err(ec_dev->dev,
			"cs-deassert spi transfer failed: %d\n",
			ret);
	}

	return ret;
}

/**
 * receive_n_bytes - receive n bytes from the EC.
 *
 * Assumes buf is a pointer into the ec_dev->din buffer
 */
static int receive_n_bytes(struct cros_ec_device *ec_dev, u8 *buf, int n)
{
	struct cros_ec_spi *ec_spi = ec_dev->priv;
	struct spi_transfer trans;
	struct spi_message msg;
	int ret;

	BUG_ON(buf - ec_dev->din + n > ec_dev->din_size);

	memset(&trans, 0, sizeof(trans));
	trans.cs_change = 1;
	trans.rx_buf = buf;
	trans.len = n;

	spi_message_init(&msg);
	spi_message_add_tail(&trans, &msg);
	ret = spi_sync(ec_spi->spi, &msg);
	if (ret < 0)
		dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);

	return ret;
}

/**
 * cros_ec_spi_receive_packet - Receive a packet from the EC.
 *
 * This function has two phases: reading the preamble bytes (since if we read
 * data from the EC before it is ready to send, we just get preamble) and
 * reading the actual message.
 *
 * The received data is placed into ec_dev->din.
 *
 * @ec_dev: ChromeOS EC device
 * @need_len: Number of message bytes we need to read
 */
static int cros_ec_spi_receive_packet(struct cros_ec_device *ec_dev,
				      int need_len)
{
	struct ec_host_response *response;
	u8 *ptr, *end;
	int ret;
	unsigned long deadline;
	int todo;

	BUG_ON(EC_MSG_PREAMBLE_COUNT > ec_dev->din_size);

	/* Receive data until we see the header byte */
	deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
	while (true) {
		unsigned long start_jiffies = jiffies;

		ret = receive_n_bytes(ec_dev,
				      ec_dev->din,
				      EC_MSG_PREAMBLE_COUNT);
		if (ret < 0)
			return ret;

		ptr = ec_dev->din;
		for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
			if (*ptr == EC_SPI_FRAME_START) {
				dev_dbg(ec_dev->dev, "msg found at %zd\n",
					ptr - ec_dev->din);
				break;
			}
		}
		if (ptr != end)
			break;

		/*
		 * Use the time at the start of the loop as a timeout.  This
		 * gives us one last shot at getting the transfer and is useful
		 * in case we got context switched out for a while.
		 */
		if (time_after(start_jiffies, deadline)) {
			dev_warn(ec_dev->dev, "EC failed to respond in time\n");
			return -ETIMEDOUT;
		}
	}

	/*
	 * ptr now points to the header byte. Copy any valid data to the
	 * start of our buffer
	 */
	todo = end - ++ptr;
	BUG_ON(todo < 0 || todo > ec_dev->din_size);
	todo = min(todo, need_len);
	memmove(ec_dev->din, ptr, todo);
	ptr = ec_dev->din + todo;
	dev_dbg(ec_dev->dev, "need %d, got %d bytes from preamble\n",
		need_len, todo);
	need_len -= todo;

	/* If the entire response struct wasn't read, get the rest of it. */
	if (todo < sizeof(*response)) {
		ret = receive_n_bytes(ec_dev, ptr, sizeof(*response) - todo);
		if (ret < 0)
			return -EBADMSG;
		ptr += (sizeof(*response) - todo);
		todo = sizeof(*response);
	}

	response = (struct ec_host_response *)ec_dev->din;

	/* Abort if data_len is too large. */
	if (response->data_len > ec_dev->din_size)
		return -EMSGSIZE;

	/* Receive data until we have it all */
	while (need_len > 0) {
		/*
		 * We can't support transfers larger than the SPI FIFO size
		 * unless we have DMA. We don't have DMA on the ISP SPI ports
		 * for Exynos. We need a way of asking SPI driver for
		 * maximum-supported transfer size.
		 */
		todo = min(need_len, 256);
		dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
			todo, need_len, ptr - ec_dev->din);

		ret = receive_n_bytes(ec_dev, ptr, todo);
		if (ret < 0)
			return ret;

		ptr += todo;
		need_len -= todo;
	}

	dev_dbg(ec_dev->dev, "loop done, ptr=%zd\n", ptr - ec_dev->din);

	return 0;
}

/**
 * cros_ec_spi_receive_response - Receive a response from the EC.
 *
 * This function has two phases: reading the preamble bytes (since if we read
 * data from the EC before it is ready to send, we just get preamble) and
 * reading the actual message.
 *
 * The received data is placed into ec_dev->din.
 *
 * @ec_dev: ChromeOS EC device
 * @need_len: Number of message bytes we need to read
 */
static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev,
					int need_len)
{
	u8 *ptr, *end;
	int ret;
	unsigned long deadline;
	int todo;

	BUG_ON(EC_MSG_PREAMBLE_COUNT > ec_dev->din_size);

	/* Receive data until we see the header byte */
	deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
	while (true) {
		unsigned long start_jiffies = jiffies;

		ret = receive_n_bytes(ec_dev,
				      ec_dev->din,
				      EC_MSG_PREAMBLE_COUNT);
		if (ret < 0)
			return ret;

		ptr = ec_dev->din;
		for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
			if (*ptr == EC_SPI_FRAME_START) {
				dev_dbg(ec_dev->dev, "msg found at %zd\n",
					ptr - ec_dev->din);
				break;
			}
		}
		if (ptr != end)
			break;

		/*
		 * Use the time at the start of the loop as a timeout.  This
		 * gives us one last shot at getting the transfer and is useful
		 * in case we got context switched out for a while.
		 */
		if (time_after(start_jiffies, deadline)) {
			dev_warn(ec_dev->dev, "EC failed to respond in time\n");
			return -ETIMEDOUT;
		}
	}

	/*
	 * ptr now points to the header byte. Copy any valid data to the
	 * start of our buffer
	 */
	todo = end - ++ptr;
	BUG_ON(todo < 0 || todo > ec_dev->din_size);
	todo = min(todo, need_len);
	memmove(ec_dev->din, ptr, todo);
	ptr = ec_dev->din + todo;
	dev_dbg(ec_dev->dev, "need %d, got %d bytes from preamble\n",
		 need_len, todo);
	need_len -= todo;

	/* Receive data until we have it all */
	while (need_len > 0) {
		/*
		 * We can't support transfers larger than the SPI FIFO size
		 * unless we have DMA. We don't have DMA on the ISP SPI ports
		 * for Exynos. We need a way of asking SPI driver for
		 * maximum-supported transfer size.
		 */
		todo = min(need_len, 256);
		dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
			todo, need_len, ptr - ec_dev->din);

		ret = receive_n_bytes(ec_dev, ptr, todo);
		if (ret < 0)
			return ret;

		debug_packet(ec_dev->dev, "interim", ptr, todo);
		ptr += todo;
		need_len -= todo;
	}

	dev_dbg(ec_dev->dev, "loop done, ptr=%zd\n", ptr - ec_dev->din);

	return 0;
}

/**
 * cros_ec_pkt_xfer_spi - Transfer a packet over SPI and receive the reply
 *
 * @ec_dev: ChromeOS EC device
 * @ec_msg: Message to transfer
 */
static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
				struct cros_ec_command *ec_msg)
{
	struct ec_host_request *request;
	struct ec_host_response *response;
	struct cros_ec_spi *ec_spi = ec_dev->priv;
	struct spi_transfer trans, trans_delay;
	struct spi_message msg;
	int i, len;
	u8 *ptr;
	u8 *rx_buf;
	u8 sum;
	int ret = 0, final_ret;

	len = cros_ec_prepare_tx(ec_dev, ec_msg);
	request = (struct ec_host_request *)ec_dev->dout;
	dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);

	/* If it's too soon to do another transaction, wait */
	if (ec_spi->last_transfer_ns) {
		unsigned long delay;	/* The delay completed so far */

		delay = ktime_get_ns() - ec_spi->last_transfer_ns;
		if (delay < EC_SPI_RECOVERY_TIME_NS)
			ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
	}

	rx_buf = kzalloc(len, GFP_KERNEL);
	if (!rx_buf) {
		ret = -ENOMEM;
		goto exit;
	}

	/*
	 * Leave a gap between CS assertion and clocking of data to allow the
	 * EC time to wakeup.
	 */
	spi_message_init(&msg);
	if (ec_spi->start_of_msg_delay) {
		memset(&trans_delay, 0, sizeof(trans_delay));
		trans_delay.delay_usecs = ec_spi->start_of_msg_delay;
		spi_message_add_tail(&trans_delay, &msg);
	}

	/* Transmit phase - send our message */
	memset(&trans, 0, sizeof(trans));
	trans.tx_buf = ec_dev->dout;
	trans.rx_buf = rx_buf;
	trans.len = len;
	trans.cs_change = 1;
	spi_message_add_tail(&trans, &msg);
	ret = spi_sync(ec_spi->spi, &msg);

	/* Get the response */
	if (!ret) {
		/* Verify that EC can process command */
		for (i = 0; i < len; i++) {
			switch (rx_buf[i]) {
			case EC_SPI_PAST_END:
			case EC_SPI_RX_BAD_DATA:
			case EC_SPI_NOT_READY:
				ret = -EAGAIN;
				ec_msg->result = EC_RES_IN_PROGRESS;
			default:
				break;
			}
			if (ret)
				break;
		}
		if (!ret)
			ret = cros_ec_spi_receive_packet(ec_dev,
					ec_msg->insize + sizeof(*response));
	} else {
		dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
	}

	final_ret = terminate_request(ec_dev);
	if (!ret)
		ret = final_ret;
	if (ret < 0)
		goto exit;

	ptr = ec_dev->din;

	/* check response error code */
	response = (struct ec_host_response *)ptr;
	ec_msg->result = response->result;

	ret = cros_ec_check_result(ec_dev, ec_msg);
	if (ret)
		goto exit;

	len = response->data_len;
	sum = 0;
	if (len > ec_msg->insize) {
		dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
			len, ec_msg->insize);
		ret = -EMSGSIZE;
		goto exit;
	}

	for (i = 0; i < sizeof(*response); i++)
		sum += ptr[i];

	/* copy response packet payload and compute checksum */
	memcpy(ec_msg->data, ptr + sizeof(*response), len);
	for (i = 0; i < len; i++)
		sum += ec_msg->data[i];

	if (sum) {
		dev_err(ec_dev->dev,
			"bad packet checksum, calculated %x\n",
			sum);
		ret = -EBADMSG;
		goto exit;
	}

	ret = len;
exit:
	kfree(rx_buf);
	if (ec_msg->command == EC_CMD_REBOOT_EC)
		msleep(EC_REBOOT_DELAY_MS);

	return ret;
}

/**
 * cros_ec_cmd_xfer_spi - Transfer a message over SPI and receive the reply
 *
 * @ec_dev: ChromeOS EC device
 * @ec_msg: Message to transfer
 */
static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
				struct cros_ec_command *ec_msg)
{
	struct cros_ec_spi *ec_spi = ec_dev->priv;
	struct spi_transfer trans;
	struct spi_message msg;
	int i, len;
	u8 *ptr;
	u8 *rx_buf;
	int sum;
	int ret = 0, final_ret;

	len = cros_ec_prepare_tx(ec_dev, ec_msg);
	dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);

	/* If it's too soon to do another transaction, wait */
	if (ec_spi->last_transfer_ns) {
		unsigned long delay;	/* The delay completed so far */

		delay = ktime_get_ns() - ec_spi->last_transfer_ns;
		if (delay < EC_SPI_RECOVERY_TIME_NS)
			ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
	}

	rx_buf = kzalloc(len, GFP_KERNEL);
	if (!rx_buf) {
		ret = -ENOMEM;
		goto exit;
	}

	/* Transmit phase - send our message */
	debug_packet(ec_dev->dev, "out", ec_dev->dout, len);
	memset(&trans, 0, sizeof(trans));
	trans.tx_buf = ec_dev->dout;
	trans.rx_buf = rx_buf;
	trans.len = len;
	trans.cs_change = 1;
	spi_message_init(&msg);
	spi_message_add_tail(&trans, &msg);
	ret = spi_sync(ec_spi->spi, &msg);

	/* Get the response */
	if (!ret) {
		/* Verify that EC can process command */
		for (i = 0; i < len; i++) {
			switch (rx_buf[i]) {
			case EC_SPI_PAST_END:
			case EC_SPI_RX_BAD_DATA:
			case EC_SPI_NOT_READY:
				ret = -EAGAIN;
				ec_msg->result = EC_RES_IN_PROGRESS;
			default:
				break;
			}
			if (ret)
				break;
		}
		if (!ret)
			ret = cros_ec_spi_receive_response(ec_dev,
					ec_msg->insize + EC_MSG_TX_PROTO_BYTES);
	} else {
		dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
	}

	final_ret = terminate_request(ec_dev);
	if (!ret)
		ret = final_ret;
	if (ret < 0)
		goto exit;

	ptr = ec_dev->din;

	/* check response error code */
	ec_msg->result = ptr[0];
	ret = cros_ec_check_result(ec_dev, ec_msg);
	if (ret)
		goto exit;

	len = ptr[1];
	sum = ptr[0] + ptr[1];
	if (len > ec_msg->insize) {
		dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
			len, ec_msg->insize);
		ret = -ENOSPC;
		goto exit;
	}

	/* copy response packet payload and compute checksum */
	for (i = 0; i < len; i++) {
		sum += ptr[i + 2];
		if (ec_msg->insize)
			ec_msg->data[i] = ptr[i + 2];
	}
	sum &= 0xff;

	debug_packet(ec_dev->dev, "in", ptr, len + 3);

	if (sum != ptr[len + 2]) {
		dev_err(ec_dev->dev,
			"bad packet checksum, expected %02x, got %02x\n",
			sum, ptr[len + 2]);
		ret = -EBADMSG;
		goto exit;
	}

	ret = len;
exit:
	kfree(rx_buf);
	if (ec_msg->command == EC_CMD_REBOOT_EC)
		msleep(EC_REBOOT_DELAY_MS);

	return ret;
}

static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev)
{
	struct device_node *np = dev->of_node;
	u32 val;
	int ret;

	ret = of_property_read_u32(np, "google,cros-ec-spi-pre-delay", &val);
	if (!ret)
		ec_spi->start_of_msg_delay = val;

	ret = of_property_read_u32(np, "google,cros-ec-spi-msg-delay", &val);
	if (!ret)
		ec_spi->end_of_msg_delay = val;
}

static int cros_ec_spi_probe(struct spi_device *spi)
{
	struct device *dev = &spi->dev;
	struct cros_ec_device *ec_dev;
	struct cros_ec_spi *ec_spi;
	int err;

	spi->bits_per_word = 8;
	spi->mode = SPI_MODE_0;
	err = spi_setup(spi);
	if (err < 0)
		return err;

	ec_spi = devm_kzalloc(dev, sizeof(*ec_spi), GFP_KERNEL);
	if (ec_spi == NULL)
		return -ENOMEM;
	ec_spi->spi = spi;
	ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
	if (!ec_dev)
		return -ENOMEM;

	/* Check for any DT properties */
	cros_ec_spi_dt_probe(ec_spi, dev);

	spi_set_drvdata(spi, ec_dev);
	ec_dev->dev = dev;
	ec_dev->priv = ec_spi;
	ec_dev->irq = spi->irq;
	ec_dev->cmd_xfer = cros_ec_cmd_xfer_spi;
	ec_dev->pkt_xfer = cros_ec_pkt_xfer_spi;
	ec_dev->phys_name = dev_name(&ec_spi->spi->dev);
	ec_dev->din_size = EC_MSG_PREAMBLE_COUNT +
			   sizeof(struct ec_host_response) +
			   sizeof(struct ec_response_get_protocol_info);
	ec_dev->dout_size = sizeof(struct ec_host_request);


	err = cros_ec_register(ec_dev);
	if (err) {
		dev_err(dev, "cannot register EC\n");
		return err;
	}

	device_init_wakeup(&spi->dev, true);

	return 0;
}

static int cros_ec_spi_remove(struct spi_device *spi)
{
	struct cros_ec_device *ec_dev;

	ec_dev = spi_get_drvdata(spi);
	cros_ec_remove(ec_dev);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int cros_ec_spi_suspend(struct device *dev)
{
	struct cros_ec_device *ec_dev = dev_get_drvdata(dev);

	return cros_ec_suspend(ec_dev);
}

static int cros_ec_spi_resume(struct device *dev)
{
	struct cros_ec_device *ec_dev = dev_get_drvdata(dev);

	return cros_ec_resume(ec_dev);
}
#endif

static SIMPLE_DEV_PM_OPS(cros_ec_spi_pm_ops, cros_ec_spi_suspend,
			 cros_ec_spi_resume);

static const struct of_device_id cros_ec_spi_of_match[] = {
	{ .compatible = "google,cros-ec-spi", },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, cros_ec_spi_of_match);

static const struct spi_device_id cros_ec_spi_id[] = {
	{ "cros-ec-spi", 0 },
	{ }
};
MODULE_DEVICE_TABLE(spi, cros_ec_spi_id);

static struct spi_driver cros_ec_driver_spi = {
	.driver	= {
		.name	= "cros-ec-spi",
		.of_match_table = of_match_ptr(cros_ec_spi_of_match),
		.owner	= THIS_MODULE,
		.pm	= &cros_ec_spi_pm_ops,
	},
	.probe		= cros_ec_spi_probe,
	.remove		= cros_ec_spi_remove,
	.id_table	= cros_ec_spi_id,
};

module_spi_driver(cros_ec_driver_spi);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("ChromeOS EC multi function device (SPI)");