summaryrefslogtreecommitdiffstats
path: root/drivers/char/tpm/tpm_i2c_infineon.c
blob: c1dd39eaaeebb1f474d2d9f8b0d1e98e3559f27f (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
732
733
734
735
736
737
738
739
/*
 * Copyright (C) 2012,2013 Infineon Technologies
 *
 * Authors:
 * Peter Huewe <peter.huewe@infineon.com>
 *
 * Device driver for TCG/TCPA TPM (trusted platform module).
 * Specifications at www.trustedcomputinggroup.org
 *
 * This device driver implements the TPM interface as defined in
 * the TCG TPM Interface Spec version 1.2, revision 1.0 and the
 * Infineon I2C Protocol Stack Specification v0.20.
 *
 * It is based on the original tpm_tis device driver from Leendert van
 * Dorn and Kyleen Hall.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, version 2 of the
 * License.
 *
 *
 */
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/wait.h>
#include "tpm.h"

/* max. buffer size supported by our TPM */
#define TPM_BUFSIZE 1260

/* max. number of iterations after I2C NAK */
#define MAX_COUNT 3

#define SLEEP_DURATION_LOW 55
#define SLEEP_DURATION_HI 65

/* max. number of iterations after I2C NAK for 'long' commands
 * we need this especially for sending TPM_READY, since the cleanup after the
 * transtion to the ready state may take some time, but it is unpredictable
 * how long it will take.
 */
#define MAX_COUNT_LONG 50

#define SLEEP_DURATION_LONG_LOW 200
#define SLEEP_DURATION_LONG_HI 220

/* After sending TPM_READY to 'reset' the TPM we have to sleep even longer */
#define SLEEP_DURATION_RESET_LOW 2400
#define SLEEP_DURATION_RESET_HI 2600

/* we want to use usleep_range instead of msleep for the 5ms TPM_TIMEOUT */
#define TPM_TIMEOUT_US_LOW (TPM_TIMEOUT * 1000)
#define TPM_TIMEOUT_US_HI  (TPM_TIMEOUT_US_LOW + 2000)

/* expected value for DIDVID register */
#define TPM_TIS_I2C_DID_VID_9635 0xd1150b00L
#define TPM_TIS_I2C_DID_VID_9645 0x001a15d1L

enum i2c_chip_type {
	SLB9635,
	SLB9645,
	UNKNOWN,
};

/* Structure to store I2C TPM specific stuff */
struct tpm_inf_dev {
	struct i2c_client *client;
	int locality;
	u8 buf[TPM_BUFSIZE + sizeof(u8)]; /* max. buffer size + addr */
	struct tpm_chip *chip;
	enum i2c_chip_type chip_type;
	unsigned int adapterlimit;
};

static struct tpm_inf_dev tpm_dev;

/*
 * iic_tpm_read() - read from TPM register
 * @addr: register address to read from
 * @buffer: provided by caller
 * @len: number of bytes to read
 *
 * Read len bytes from TPM register and put them into
 * buffer (little-endian format, i.e. first byte is put into buffer[0]).
 *
 * NOTE: TPM is big-endian for multi-byte values. Multi-byte
 * values have to be swapped.
 *
 * NOTE: We can't unfortunately use the combined read/write functions
 * provided by the i2c core as the TPM currently does not support the
 * repeated start condition and due to it's special requirements.
 * The i2c_smbus* functions do not work for this chip.
 *
 * Return -EIO on error, 0 on success.
 */
static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
{

	struct i2c_msg msg1 = {
		.addr = tpm_dev.client->addr,
		.len = 1,
		.buf = &addr
	};
	struct i2c_msg msg2 = {
		.addr = tpm_dev.client->addr,
		.flags = I2C_M_RD,
		.len = len,
		.buf = buffer
	};
	struct i2c_msg msgs[] = {msg1, msg2};

	int rc = 0;
	int count;
	unsigned int msglen = len;

	/* Lock the adapter for the duration of the whole sequence. */
	if (!tpm_dev.client->adapter->algo->master_xfer)
		return -EOPNOTSUPP;
	i2c_lock_adapter(tpm_dev.client->adapter);

	if (tpm_dev.chip_type == SLB9645) {
		/* use a combined read for newer chips
		 * unfortunately the smbus functions are not suitable due to
		 * the 32 byte limit of the smbus.
		 * retries should usually not be needed, but are kept just to
		 * be on the safe side.
		 */
		for (count = 0; count < MAX_COUNT; count++) {
			rc = __i2c_transfer(tpm_dev.client->adapter, msgs, 2);
			if (rc > 0)
				break;	/* break here to skip sleep */
			usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
		}
	} else {
		/* Expect to send one command message and one data message, but
		 * support looping over each or both if necessary.
		 */
		while (len > 0) {
			/* slb9635 protocol should work in all cases */
			for (count = 0; count < MAX_COUNT; count++) {
				rc = __i2c_transfer(tpm_dev.client->adapter,
						    &msg1, 1);
				if (rc > 0)
					break;	/* break here to skip sleep */

				usleep_range(SLEEP_DURATION_LOW,
					     SLEEP_DURATION_HI);
			}

			if (rc <= 0)
				goto out;

			/* After the TPM has successfully received the register
			 * address it needs some time, thus we're sleeping here
			 * again, before retrieving the data
			 */
			for (count = 0; count < MAX_COUNT; count++) {
				if (tpm_dev.adapterlimit) {
					msglen = min_t(unsigned int,
						       tpm_dev.adapterlimit,
						       len);
					msg2.len = msglen;
				}
				usleep_range(SLEEP_DURATION_LOW,
					     SLEEP_DURATION_HI);
				rc = __i2c_transfer(tpm_dev.client->adapter,
						    &msg2, 1);
				if (rc > 0) {
					/* Since len is unsigned, make doubly
					 * sure we do not underflow it.
					 */
					if (msglen > len)
						len = 0;
					else
						len -= msglen;
					msg2.buf += msglen;
					break;
				}
				/* If the I2C adapter rejected the request (e.g
				 * when the quirk read_max_len < len) fall back
				 * to a sane minimum value and try again.
				 */
				if (rc == -EOPNOTSUPP)
					tpm_dev.adapterlimit =
							I2C_SMBUS_BLOCK_MAX;
			}

			if (rc <= 0)
				goto out;
		}
	}

out:
	i2c_unlock_adapter(tpm_dev.client->adapter);
	/* take care of 'guard time' */
	usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);

	/* __i2c_transfer returns the number of successfully transferred
	 * messages.
	 * So rc should be greater than 0 here otherwise we have an error.
	 */
	if (rc <= 0)
		return -EIO;

	return 0;
}

static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
				 unsigned int sleep_low,
				 unsigned int sleep_hi, u8 max_count)
{
	int rc = -EIO;
	int count;

	struct i2c_msg msg1 = {
		.addr = tpm_dev.client->addr,
		.len = len + 1,
		.buf = tpm_dev.buf
	};

	if (len > TPM_BUFSIZE)
		return -EINVAL;

	if (!tpm_dev.client->adapter->algo->master_xfer)
		return -EOPNOTSUPP;
	i2c_lock_adapter(tpm_dev.client->adapter);

	/* prepend the 'register address' to the buffer */
	tpm_dev.buf[0] = addr;
	memcpy(&(tpm_dev.buf[1]), buffer, len);

	/*
	 * NOTE: We have to use these special mechanisms here and unfortunately
	 * cannot rely on the standard behavior of i2c_transfer.
	 * Even for newer chips the smbus functions are not
	 * suitable due to the 32 byte limit of the smbus.
	 */
	for (count = 0; count < max_count; count++) {
		rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
		if (rc > 0)
			break;
		usleep_range(sleep_low, sleep_hi);
	}

	i2c_unlock_adapter(tpm_dev.client->adapter);
	/* take care of 'guard time' */
	usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);

	/* __i2c_transfer returns the number of successfully transferred
	 * messages.
	 * So rc should be greater than 0 here otherwise we have an error.
	 */
	if (rc <= 0)
		return -EIO;

	return 0;
}

/*
 * iic_tpm_write() - write to TPM register
 * @addr: register address to write to
 * @buffer: containing data to be written
 * @len: number of bytes to write
 *
 * Write len bytes from provided buffer to TPM register (little
 * endian format, i.e. buffer[0] is written as first byte).
 *
 * NOTE: TPM is big-endian for multi-byte values. Multi-byte
 * values have to be swapped.
 *
 * NOTE: use this function instead of the iic_tpm_write_generic function.
 *
 * Return -EIO on error, 0 on success
 */
static int iic_tpm_write(u8 addr, u8 *buffer, size_t len)
{
	return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LOW,
				     SLEEP_DURATION_HI, MAX_COUNT);
}

/*
 * This function is needed especially for the cleanup situation after
 * sending TPM_READY
 * */
static int iic_tpm_write_long(u8 addr, u8 *buffer, size_t len)
{
	return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LONG_LOW,
				     SLEEP_DURATION_LONG_HI, MAX_COUNT_LONG);
}

enum tis_access {
	TPM_ACCESS_VALID = 0x80,
	TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
	TPM_ACCESS_REQUEST_PENDING = 0x04,
	TPM_ACCESS_REQUEST_USE = 0x02,
};

enum tis_status {
	TPM_STS_VALID = 0x80,
	TPM_STS_COMMAND_READY = 0x40,
	TPM_STS_GO = 0x20,
	TPM_STS_DATA_AVAIL = 0x10,
	TPM_STS_DATA_EXPECT = 0x08,
};

enum tis_defaults {
	TIS_SHORT_TIMEOUT = 750,	/* ms */
	TIS_LONG_TIMEOUT = 2000,	/* 2 sec */
};

#define	TPM_ACCESS(l)			(0x0000 | ((l) << 4))
#define	TPM_STS(l)			(0x0001 | ((l) << 4))
#define	TPM_DATA_FIFO(l)		(0x0005 | ((l) << 4))
#define	TPM_DID_VID(l)			(0x0006 | ((l) << 4))

static bool check_locality(struct tpm_chip *chip, int loc)
{
	u8 buf;
	int rc;

	rc = iic_tpm_read(TPM_ACCESS(loc), &buf, 1);
	if (rc < 0)
		return false;

	if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
	    (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
		tpm_dev.locality = loc;
		return true;
	}

	return false;
}

/* implementation similar to tpm_tis */
static void release_locality(struct tpm_chip *chip, int loc, int force)
{
	u8 buf;
	if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0)
		return;

	if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
	    (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) {
		buf = TPM_ACCESS_ACTIVE_LOCALITY;
		iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
	}
}

static int request_locality(struct tpm_chip *chip, int loc)
{
	unsigned long stop;
	u8 buf = TPM_ACCESS_REQUEST_USE;

	if (check_locality(chip, loc))
		return loc;

	iic_tpm_write(TPM_ACCESS(loc), &buf, 1);

	/* wait for burstcount */
	stop = jiffies + chip->timeout_a;
	do {
		if (check_locality(chip, loc))
			return loc;
		usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
	} while (time_before(jiffies, stop));

	return -ETIME;
}

static u8 tpm_tis_i2c_status(struct tpm_chip *chip)
{
	/* NOTE: since I2C read may fail, return 0 in this case --> time-out */
	u8 buf = 0xFF;
	u8 i = 0;

	do {
		if (iic_tpm_read(TPM_STS(tpm_dev.locality), &buf, 1) < 0)
			return 0;

		i++;
	/* if locallity is set STS should not be 0xFF */
	} while ((buf == 0xFF) && i < 10);

	return buf;
}

static void tpm_tis_i2c_ready(struct tpm_chip *chip)
{
	/* this causes the current command to be aborted */
	u8 buf = TPM_STS_COMMAND_READY;
	iic_tpm_write_long(TPM_STS(tpm_dev.locality), &buf, 1);
}

static ssize_t get_burstcount(struct tpm_chip *chip)
{
	unsigned long stop;
	ssize_t burstcnt;
	u8 buf[3];

	/* wait for burstcount */
	/* which timeout value, spec has 2 answers (c & d) */
	stop = jiffies + chip->timeout_d;
	do {
		/* Note: STS is little endian */
		if (iic_tpm_read(TPM_STS(tpm_dev.locality)+1, buf, 3) < 0)
			burstcnt = 0;
		else
			burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0];

		if (burstcnt)
			return burstcnt;

		usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
	} while (time_before(jiffies, stop));
	return -EBUSY;
}

static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
			 int *status)
{
	unsigned long stop;

	/* check current status */
	*status = tpm_tis_i2c_status(chip);
	if ((*status != 0xFF) && (*status & mask) == mask)
		return 0;

	stop = jiffies + timeout;
	do {
		/* since we just checked the status, give the TPM some time */
		usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
		*status = tpm_tis_i2c_status(chip);
		if ((*status & mask) == mask)
			return 0;

	} while (time_before(jiffies, stop));

	return -ETIME;
}

static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
{
	size_t size = 0;
	ssize_t burstcnt;
	u8 retries = 0;
	int rc;

	while (size < count) {
		burstcnt = get_burstcount(chip);

		/* burstcnt < 0 = TPM is busy */
		if (burstcnt < 0)
			return burstcnt;

		/* limit received data to max. left */
		if (burstcnt > (count - size))
			burstcnt = count - size;

		rc = iic_tpm_read(TPM_DATA_FIFO(tpm_dev.locality),
				  &(buf[size]), burstcnt);
		if (rc == 0)
			size += burstcnt;
		else if (rc < 0)
			retries++;

		/* avoid endless loop in case of broken HW */
		if (retries > MAX_COUNT_LONG)
			return -EIO;
	}
	return size;
}

static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
{
	int size = 0;
	int expected, status;

	if (count < TPM_HEADER_SIZE) {
		size = -EIO;
		goto out;
	}

	/* read first 10 bytes, including tag, paramsize, and result */
	size = recv_data(chip, buf, TPM_HEADER_SIZE);
	if (size < TPM_HEADER_SIZE) {
		dev_err(&chip->dev, "Unable to read header\n");
		goto out;
	}

	expected = be32_to_cpu(*(__be32 *)(buf + 2));
	if ((size_t) expected > count) {
		size = -EIO;
		goto out;
	}

	size += recv_data(chip, &buf[TPM_HEADER_SIZE],
			  expected - TPM_HEADER_SIZE);
	if (size < expected) {
		dev_err(&chip->dev, "Unable to read remainder of result\n");
		size = -ETIME;
		goto out;
	}

	wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
	if (status & TPM_STS_DATA_AVAIL) {	/* retry? */
		dev_err(&chip->dev, "Error left over data\n");
		size = -EIO;
		goto out;
	}

out:
	tpm_tis_i2c_ready(chip);
	/* The TPM needs some time to clean up here,
	 * so we sleep rather than keeping the bus busy
	 */
	usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
	release_locality(chip, tpm_dev.locality, 0);
	return size;
}

static int tpm_tis_i2c_send(struct tpm_chip *chip, u8 *buf, size_t len)
{
	int rc, status;
	ssize_t burstcnt;
	size_t count = 0;
	u8 retries = 0;
	u8 sts = TPM_STS_GO;

	if (len > TPM_BUFSIZE)
		return -E2BIG;	/* command is too long for our tpm, sorry */

	if (request_locality(chip, 0) < 0)
		return -EBUSY;

	status = tpm_tis_i2c_status(chip);
	if ((status & TPM_STS_COMMAND_READY) == 0) {
		tpm_tis_i2c_ready(chip);
		if (wait_for_stat
		    (chip, TPM_STS_COMMAND_READY,
		     chip->timeout_b, &status) < 0) {
			rc = -ETIME;
			goto out_err;
		}
	}

	while (count < len - 1) {
		burstcnt = get_burstcount(chip);

		/* burstcnt < 0 = TPM is busy */
		if (burstcnt < 0)
			return burstcnt;

		if (burstcnt > (len - 1 - count))
			burstcnt = len - 1 - count;

		rc = iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality),
				   &(buf[count]), burstcnt);
		if (rc == 0)
			count += burstcnt;
		else if (rc < 0)
			retries++;

		/* avoid endless loop in case of broken HW */
		if (retries > MAX_COUNT_LONG) {
			rc = -EIO;
			goto out_err;
		}

		wait_for_stat(chip, TPM_STS_VALID,
			      chip->timeout_c, &status);

		if ((status & TPM_STS_DATA_EXPECT) == 0) {
			rc = -EIO;
			goto out_err;
		}
	}

	/* write last byte */
	iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality), &(buf[count]), 1);
	wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
	if ((status & TPM_STS_DATA_EXPECT) != 0) {
		rc = -EIO;
		goto out_err;
	}

	/* go and do it */
	iic_tpm_write(TPM_STS(tpm_dev.locality), &sts, 1);

	return len;
out_err:
	tpm_tis_i2c_ready(chip);
	/* The TPM needs some time to clean up here,
	 * so we sleep rather than keeping the bus busy
	 */
	usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
	release_locality(chip, tpm_dev.locality, 0);
	return rc;
}

static bool tpm_tis_i2c_req_canceled(struct tpm_chip *chip, u8 status)
{
	return (status == TPM_STS_COMMAND_READY);
}

static const struct tpm_class_ops tpm_tis_i2c = {
	.flags = TPM_OPS_AUTO_STARTUP,
	.status = tpm_tis_i2c_status,
	.recv = tpm_tis_i2c_recv,
	.send = tpm_tis_i2c_send,
	.cancel = tpm_tis_i2c_ready,
	.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
	.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
	.req_canceled = tpm_tis_i2c_req_canceled,
};

static int tpm_tis_i2c_init(struct device *dev)
{
	u32 vendor;
	int rc = 0;
	struct tpm_chip *chip;

	chip = tpmm_chip_alloc(dev, &tpm_tis_i2c);
	if (IS_ERR(chip))
		return PTR_ERR(chip);

	/* Default timeouts */
	chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
	chip->timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
	chip->timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
	chip->timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);

	if (request_locality(chip, 0) != 0) {
		dev_err(dev, "could not request locality\n");
		rc = -ENODEV;
		goto out_err;
	}

	/* read four bytes from DID_VID register */
	if (iic_tpm_read(TPM_DID_VID(0), (u8 *)&vendor, 4) < 0) {
		dev_err(dev, "could not read vendor id\n");
		rc = -EIO;
		goto out_release;
	}

	if (vendor == TPM_TIS_I2C_DID_VID_9645) {
		tpm_dev.chip_type = SLB9645;
	} else if (vendor == TPM_TIS_I2C_DID_VID_9635) {
		tpm_dev.chip_type = SLB9635;
	} else {
		dev_err(dev, "vendor id did not match! ID was %08x\n", vendor);
		rc = -ENODEV;
		goto out_release;
	}

	dev_info(dev, "1.2 TPM (device-id 0x%X)\n", vendor >> 16);

	tpm_dev.chip = chip;

	return tpm_chip_register(chip);
out_release:
	release_locality(chip, tpm_dev.locality, 1);
	tpm_dev.client = NULL;
out_err:
	return rc;
}

static const struct i2c_device_id tpm_tis_i2c_table[] = {
	{"tpm_i2c_infineon"},
	{"slb9635tt"},
	{"slb9645tt"},
	{},
};

MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_table);

#ifdef CONFIG_OF
static const struct of_device_id tpm_tis_i2c_of_match[] = {
	{.compatible = "infineon,tpm_i2c_infineon"},
	{.compatible = "infineon,slb9635tt"},
	{.compatible = "infineon,slb9645tt"},
	{},
};
MODULE_DEVICE_TABLE(of, tpm_tis_i2c_of_match);
#endif

static SIMPLE_DEV_PM_OPS(tpm_tis_i2c_ops, tpm_pm_suspend, tpm_pm_resume);

static int tpm_tis_i2c_probe(struct i2c_client *client,
			     const struct i2c_device_id *id)
{
	int rc;
	struct device *dev = &(client->dev);

	if (tpm_dev.client != NULL) {
		dev_err(dev, "This driver only supports one client at a time\n");
		return -EBUSY;	/* We only support one client */
	}

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
		dev_err(dev, "no algorithms associated to the i2c bus\n");
		return -ENODEV;
	}

	tpm_dev.client = client;
	rc = tpm_tis_i2c_init(&client->dev);
	if (rc != 0) {
		tpm_dev.client = NULL;
		rc = -ENODEV;
	}
	return rc;
}

static int tpm_tis_i2c_remove(struct i2c_client *client)
{
	struct tpm_chip *chip = tpm_dev.chip;

	tpm_chip_unregister(chip);
	release_locality(chip, tpm_dev.locality, 1);
	tpm_dev.client = NULL;

	return 0;
}

static struct i2c_driver tpm_tis_i2c_driver = {
	.id_table = tpm_tis_i2c_table,
	.probe = tpm_tis_i2c_probe,
	.remove = tpm_tis_i2c_remove,
	.driver = {
		   .name = "tpm_i2c_infineon",
		   .pm = &tpm_tis_i2c_ops,
		   .of_match_table = of_match_ptr(tpm_tis_i2c_of_match),
		   },
};

module_i2c_driver(tpm_tis_i2c_driver);
MODULE_AUTHOR("Peter Huewe <peter.huewe@infineon.com>");
MODULE_DESCRIPTION("TPM TIS I2C Infineon Driver");
MODULE_VERSION("2.2.0");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud