1 /*
2  * Copyright (C) 2012,2013 Infineon Technologies
3  *
4  * Authors:
5  * Peter Huewe <peter.huewe@infineon.com>
6  *
7  * Device driver for TCG/TCPA TPM (trusted platform module).
8  * Specifications at www.trustedcomputinggroup.org
9  *
10  * This device driver implements the TPM interface as defined in
11  * the TCG TPM Interface Spec version 1.2, revision 1.0 and the
12  * Infineon I2C Protocol Stack Specification v0.20.
13  *
14  * It is based on the original tpm_tis device driver from Leendert van
15  * Dorn and Kyleen Hall.
16  *
17  * This program is free software; you can redistribute it and/or
18  * modify it under the terms of the GNU General Public License as
19  * published by the Free Software Foundation, version 2 of the
20  * License.
21  *
22  *
23  */
24 #include <linux/i2c.h>
25 #include <linux/module.h>
26 #include <linux/wait.h>
27 #include "tpm.h"
28 
29 /* max. buffer size supported by our TPM */
30 #define TPM_BUFSIZE 1260
31 
32 /* max. number of iterations after I2C NAK */
33 #define MAX_COUNT 3
34 
35 #define SLEEP_DURATION_LOW 55
36 #define SLEEP_DURATION_HI 65
37 
38 /* max. number of iterations after I2C NAK for 'long' commands
39  * we need this especially for sending TPM_READY, since the cleanup after the
40  * transtion to the ready state may take some time, but it is unpredictable
41  * how long it will take.
42  */
43 #define MAX_COUNT_LONG 50
44 
45 #define SLEEP_DURATION_LONG_LOW 200
46 #define SLEEP_DURATION_LONG_HI 220
47 
48 /* After sending TPM_READY to 'reset' the TPM we have to sleep even longer */
49 #define SLEEP_DURATION_RESET_LOW 2400
50 #define SLEEP_DURATION_RESET_HI 2600
51 
52 /* we want to use usleep_range instead of msleep for the 5ms TPM_TIMEOUT */
53 #define TPM_TIMEOUT_US_LOW (TPM_TIMEOUT * 1000)
54 #define TPM_TIMEOUT_US_HI  (TPM_TIMEOUT_US_LOW + 2000)
55 
56 /* expected value for DIDVID register */
57 #define TPM_TIS_I2C_DID_VID_9635 0xd1150b00L
58 #define TPM_TIS_I2C_DID_VID_9645 0x001a15d1L
59 
60 enum i2c_chip_type {
61 	SLB9635,
62 	SLB9645,
63 	UNKNOWN,
64 };
65 
66 /* Structure to store I2C TPM specific stuff */
67 struct tpm_inf_dev {
68 	struct i2c_client *client;
69 	int locality;
70 	u8 buf[TPM_BUFSIZE + sizeof(u8)]; /* max. buffer size + addr */
71 	struct tpm_chip *chip;
72 	enum i2c_chip_type chip_type;
73 	unsigned int adapterlimit;
74 };
75 
76 static struct tpm_inf_dev tpm_dev;
77 
78 /*
79  * iic_tpm_read() - read from TPM register
80  * @addr: register address to read from
81  * @buffer: provided by caller
82  * @len: number of bytes to read
83  *
84  * Read len bytes from TPM register and put them into
85  * buffer (little-endian format, i.e. first byte is put into buffer[0]).
86  *
87  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
88  * values have to be swapped.
89  *
90  * NOTE: We can't unfortunately use the combined read/write functions
91  * provided by the i2c core as the TPM currently does not support the
92  * repeated start condition and due to it's special requirements.
93  * The i2c_smbus* functions do not work for this chip.
94  *
95  * Return -EIO on error, 0 on success.
96  */
97 static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
98 {
99 
100 	struct i2c_msg msg1 = {
101 		.addr = tpm_dev.client->addr,
102 		.len = 1,
103 		.buf = &addr
104 	};
105 	struct i2c_msg msg2 = {
106 		.addr = tpm_dev.client->addr,
107 		.flags = I2C_M_RD,
108 		.len = len,
109 		.buf = buffer
110 	};
111 	struct i2c_msg msgs[] = {msg1, msg2};
112 
113 	int rc = 0;
114 	int count;
115 	unsigned int msglen = len;
116 
117 	/* Lock the adapter for the duration of the whole sequence. */
118 	if (!tpm_dev.client->adapter->algo->master_xfer)
119 		return -EOPNOTSUPP;
120 	i2c_lock_adapter(tpm_dev.client->adapter);
121 
122 	if (tpm_dev.chip_type == SLB9645) {
123 		/* use a combined read for newer chips
124 		 * unfortunately the smbus functions are not suitable due to
125 		 * the 32 byte limit of the smbus.
126 		 * retries should usually not be needed, but are kept just to
127 		 * be on the safe side.
128 		 */
129 		for (count = 0; count < MAX_COUNT; count++) {
130 			rc = __i2c_transfer(tpm_dev.client->adapter, msgs, 2);
131 			if (rc > 0)
132 				break;	/* break here to skip sleep */
133 			usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
134 		}
135 	} else {
136 		/* Expect to send one command message and one data message, but
137 		 * support looping over each or both if necessary.
138 		 */
139 		while (len > 0) {
140 			/* slb9635 protocol should work in all cases */
141 			for (count = 0; count < MAX_COUNT; count++) {
142 				rc = __i2c_transfer(tpm_dev.client->adapter,
143 						    &msg1, 1);
144 				if (rc > 0)
145 					break;	/* break here to skip sleep */
146 
147 				usleep_range(SLEEP_DURATION_LOW,
148 					     SLEEP_DURATION_HI);
149 			}
150 
151 			if (rc <= 0)
152 				goto out;
153 
154 			/* After the TPM has successfully received the register
155 			 * address it needs some time, thus we're sleeping here
156 			 * again, before retrieving the data
157 			 */
158 			for (count = 0; count < MAX_COUNT; count++) {
159 				if (tpm_dev.adapterlimit) {
160 					msglen = min_t(unsigned int,
161 						       tpm_dev.adapterlimit,
162 						       len);
163 					msg2.len = msglen;
164 				}
165 				usleep_range(SLEEP_DURATION_LOW,
166 					     SLEEP_DURATION_HI);
167 				rc = __i2c_transfer(tpm_dev.client->adapter,
168 						    &msg2, 1);
169 				if (rc > 0) {
170 					/* Since len is unsigned, make doubly
171 					 * sure we do not underflow it.
172 					 */
173 					if (msglen > len)
174 						len = 0;
175 					else
176 						len -= msglen;
177 					msg2.buf += msglen;
178 					break;
179 				}
180 				/* If the I2C adapter rejected the request (e.g
181 				 * when the quirk read_max_len < len) fall back
182 				 * to a sane minimum value and try again.
183 				 */
184 				if (rc == -EOPNOTSUPP)
185 					tpm_dev.adapterlimit =
186 							I2C_SMBUS_BLOCK_MAX;
187 			}
188 
189 			if (rc <= 0)
190 				goto out;
191 		}
192 	}
193 
194 out:
195 	i2c_unlock_adapter(tpm_dev.client->adapter);
196 	/* take care of 'guard time' */
197 	usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
198 
199 	/* __i2c_transfer returns the number of successfully transferred
200 	 * messages.
201 	 * So rc should be greater than 0 here otherwise we have an error.
202 	 */
203 	if (rc <= 0)
204 		return -EIO;
205 
206 	return 0;
207 }
208 
209 static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
210 				 unsigned int sleep_low,
211 				 unsigned int sleep_hi, u8 max_count)
212 {
213 	int rc = -EIO;
214 	int count;
215 
216 	struct i2c_msg msg1 = {
217 		.addr = tpm_dev.client->addr,
218 		.len = len + 1,
219 		.buf = tpm_dev.buf
220 	};
221 
222 	if (len > TPM_BUFSIZE)
223 		return -EINVAL;
224 
225 	if (!tpm_dev.client->adapter->algo->master_xfer)
226 		return -EOPNOTSUPP;
227 	i2c_lock_adapter(tpm_dev.client->adapter);
228 
229 	/* prepend the 'register address' to the buffer */
230 	tpm_dev.buf[0] = addr;
231 	memcpy(&(tpm_dev.buf[1]), buffer, len);
232 
233 	/*
234 	 * NOTE: We have to use these special mechanisms here and unfortunately
235 	 * cannot rely on the standard behavior of i2c_transfer.
236 	 * Even for newer chips the smbus functions are not
237 	 * suitable due to the 32 byte limit of the smbus.
238 	 */
239 	for (count = 0; count < max_count; count++) {
240 		rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
241 		if (rc > 0)
242 			break;
243 		usleep_range(sleep_low, sleep_hi);
244 	}
245 
246 	i2c_unlock_adapter(tpm_dev.client->adapter);
247 	/* take care of 'guard time' */
248 	usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
249 
250 	/* __i2c_transfer returns the number of successfully transferred
251 	 * messages.
252 	 * So rc should be greater than 0 here otherwise we have an error.
253 	 */
254 	if (rc <= 0)
255 		return -EIO;
256 
257 	return 0;
258 }
259 
260 /*
261  * iic_tpm_write() - write to TPM register
262  * @addr: register address to write to
263  * @buffer: containing data to be written
264  * @len: number of bytes to write
265  *
266  * Write len bytes from provided buffer to TPM register (little
267  * endian format, i.e. buffer[0] is written as first byte).
268  *
269  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
270  * values have to be swapped.
271  *
272  * NOTE: use this function instead of the iic_tpm_write_generic function.
273  *
274  * Return -EIO on error, 0 on success
275  */
276 static int iic_tpm_write(u8 addr, u8 *buffer, size_t len)
277 {
278 	return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LOW,
279 				     SLEEP_DURATION_HI, MAX_COUNT);
280 }
281 
282 /*
283  * This function is needed especially for the cleanup situation after
284  * sending TPM_READY
285  * */
286 static int iic_tpm_write_long(u8 addr, u8 *buffer, size_t len)
287 {
288 	return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LONG_LOW,
289 				     SLEEP_DURATION_LONG_HI, MAX_COUNT_LONG);
290 }
291 
292 enum tis_access {
293 	TPM_ACCESS_VALID = 0x80,
294 	TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
295 	TPM_ACCESS_REQUEST_PENDING = 0x04,
296 	TPM_ACCESS_REQUEST_USE = 0x02,
297 };
298 
299 enum tis_status {
300 	TPM_STS_VALID = 0x80,
301 	TPM_STS_COMMAND_READY = 0x40,
302 	TPM_STS_GO = 0x20,
303 	TPM_STS_DATA_AVAIL = 0x10,
304 	TPM_STS_DATA_EXPECT = 0x08,
305 };
306 
307 enum tis_defaults {
308 	TIS_SHORT_TIMEOUT = 750,	/* ms */
309 	TIS_LONG_TIMEOUT = 2000,	/* 2 sec */
310 };
311 
312 #define	TPM_ACCESS(l)			(0x0000 | ((l) << 4))
313 #define	TPM_STS(l)			(0x0001 | ((l) << 4))
314 #define	TPM_DATA_FIFO(l)		(0x0005 | ((l) << 4))
315 #define	TPM_DID_VID(l)			(0x0006 | ((l) << 4))
316 
317 static bool check_locality(struct tpm_chip *chip, int loc)
318 {
319 	u8 buf;
320 	int rc;
321 
322 	rc = iic_tpm_read(TPM_ACCESS(loc), &buf, 1);
323 	if (rc < 0)
324 		return false;
325 
326 	if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
327 	    (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
328 		tpm_dev.locality = loc;
329 		return true;
330 	}
331 
332 	return false;
333 }
334 
335 /* implementation similar to tpm_tis */
336 static void release_locality(struct tpm_chip *chip, int loc, int force)
337 {
338 	u8 buf;
339 	if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0)
340 		return;
341 
342 	if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
343 	    (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) {
344 		buf = TPM_ACCESS_ACTIVE_LOCALITY;
345 		iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
346 	}
347 }
348 
349 static int request_locality(struct tpm_chip *chip, int loc)
350 {
351 	unsigned long stop;
352 	u8 buf = TPM_ACCESS_REQUEST_USE;
353 
354 	if (check_locality(chip, loc))
355 		return loc;
356 
357 	iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
358 
359 	/* wait for burstcount */
360 	stop = jiffies + chip->timeout_a;
361 	do {
362 		if (check_locality(chip, loc))
363 			return loc;
364 		usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
365 	} while (time_before(jiffies, stop));
366 
367 	return -ETIME;
368 }
369 
370 static u8 tpm_tis_i2c_status(struct tpm_chip *chip)
371 {
372 	/* NOTE: since I2C read may fail, return 0 in this case --> time-out */
373 	u8 buf = 0xFF;
374 	u8 i = 0;
375 
376 	do {
377 		if (iic_tpm_read(TPM_STS(tpm_dev.locality), &buf, 1) < 0)
378 			return 0;
379 
380 		i++;
381 	/* if locallity is set STS should not be 0xFF */
382 	} while ((buf == 0xFF) && i < 10);
383 
384 	return buf;
385 }
386 
387 static void tpm_tis_i2c_ready(struct tpm_chip *chip)
388 {
389 	/* this causes the current command to be aborted */
390 	u8 buf = TPM_STS_COMMAND_READY;
391 	iic_tpm_write_long(TPM_STS(tpm_dev.locality), &buf, 1);
392 }
393 
394 static ssize_t get_burstcount(struct tpm_chip *chip)
395 {
396 	unsigned long stop;
397 	ssize_t burstcnt;
398 	u8 buf[3];
399 
400 	/* wait for burstcount */
401 	/* which timeout value, spec has 2 answers (c & d) */
402 	stop = jiffies + chip->timeout_d;
403 	do {
404 		/* Note: STS is little endian */
405 		if (iic_tpm_read(TPM_STS(tpm_dev.locality)+1, buf, 3) < 0)
406 			burstcnt = 0;
407 		else
408 			burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0];
409 
410 		if (burstcnt)
411 			return burstcnt;
412 
413 		usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
414 	} while (time_before(jiffies, stop));
415 	return -EBUSY;
416 }
417 
418 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
419 			 int *status)
420 {
421 	unsigned long stop;
422 
423 	/* check current status */
424 	*status = tpm_tis_i2c_status(chip);
425 	if ((*status != 0xFF) && (*status & mask) == mask)
426 		return 0;
427 
428 	stop = jiffies + timeout;
429 	do {
430 		/* since we just checked the status, give the TPM some time */
431 		usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
432 		*status = tpm_tis_i2c_status(chip);
433 		if ((*status & mask) == mask)
434 			return 0;
435 
436 	} while (time_before(jiffies, stop));
437 
438 	return -ETIME;
439 }
440 
441 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
442 {
443 	size_t size = 0;
444 	ssize_t burstcnt;
445 	u8 retries = 0;
446 	int rc;
447 
448 	while (size < count) {
449 		burstcnt = get_burstcount(chip);
450 
451 		/* burstcnt < 0 = TPM is busy */
452 		if (burstcnt < 0)
453 			return burstcnt;
454 
455 		/* limit received data to max. left */
456 		if (burstcnt > (count - size))
457 			burstcnt = count - size;
458 
459 		rc = iic_tpm_read(TPM_DATA_FIFO(tpm_dev.locality),
460 				  &(buf[size]), burstcnt);
461 		if (rc == 0)
462 			size += burstcnt;
463 		else if (rc < 0)
464 			retries++;
465 
466 		/* avoid endless loop in case of broken HW */
467 		if (retries > MAX_COUNT_LONG)
468 			return -EIO;
469 	}
470 	return size;
471 }
472 
473 static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
474 {
475 	int size = 0;
476 	int status;
477 	u32 expected;
478 
479 	if (count < TPM_HEADER_SIZE) {
480 		size = -EIO;
481 		goto out;
482 	}
483 
484 	/* read first 10 bytes, including tag, paramsize, and result */
485 	size = recv_data(chip, buf, TPM_HEADER_SIZE);
486 	if (size < TPM_HEADER_SIZE) {
487 		dev_err(&chip->dev, "Unable to read header\n");
488 		goto out;
489 	}
490 
491 	expected = be32_to_cpu(*(__be32 *)(buf + 2));
492 	if (((size_t) expected > count) || (expected < TPM_HEADER_SIZE)) {
493 		size = -EIO;
494 		goto out;
495 	}
496 
497 	size += recv_data(chip, &buf[TPM_HEADER_SIZE],
498 			  expected - TPM_HEADER_SIZE);
499 	if (size < expected) {
500 		dev_err(&chip->dev, "Unable to read remainder of result\n");
501 		size = -ETIME;
502 		goto out;
503 	}
504 
505 	wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
506 	if (status & TPM_STS_DATA_AVAIL) {	/* retry? */
507 		dev_err(&chip->dev, "Error left over data\n");
508 		size = -EIO;
509 		goto out;
510 	}
511 
512 out:
513 	tpm_tis_i2c_ready(chip);
514 	/* The TPM needs some time to clean up here,
515 	 * so we sleep rather than keeping the bus busy
516 	 */
517 	usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
518 	release_locality(chip, tpm_dev.locality, 0);
519 	return size;
520 }
521 
522 static int tpm_tis_i2c_send(struct tpm_chip *chip, u8 *buf, size_t len)
523 {
524 	int rc, status;
525 	ssize_t burstcnt;
526 	size_t count = 0;
527 	u8 retries = 0;
528 	u8 sts = TPM_STS_GO;
529 
530 	if (len > TPM_BUFSIZE)
531 		return -E2BIG;	/* command is too long for our tpm, sorry */
532 
533 	if (request_locality(chip, 0) < 0)
534 		return -EBUSY;
535 
536 	status = tpm_tis_i2c_status(chip);
537 	if ((status & TPM_STS_COMMAND_READY) == 0) {
538 		tpm_tis_i2c_ready(chip);
539 		if (wait_for_stat
540 		    (chip, TPM_STS_COMMAND_READY,
541 		     chip->timeout_b, &status) < 0) {
542 			rc = -ETIME;
543 			goto out_err;
544 		}
545 	}
546 
547 	while (count < len - 1) {
548 		burstcnt = get_burstcount(chip);
549 
550 		/* burstcnt < 0 = TPM is busy */
551 		if (burstcnt < 0)
552 			return burstcnt;
553 
554 		if (burstcnt > (len - 1 - count))
555 			burstcnt = len - 1 - count;
556 
557 		rc = iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality),
558 				   &(buf[count]), burstcnt);
559 		if (rc == 0)
560 			count += burstcnt;
561 		else if (rc < 0)
562 			retries++;
563 
564 		/* avoid endless loop in case of broken HW */
565 		if (retries > MAX_COUNT_LONG) {
566 			rc = -EIO;
567 			goto out_err;
568 		}
569 
570 		wait_for_stat(chip, TPM_STS_VALID,
571 			      chip->timeout_c, &status);
572 
573 		if ((status & TPM_STS_DATA_EXPECT) == 0) {
574 			rc = -EIO;
575 			goto out_err;
576 		}
577 	}
578 
579 	/* write last byte */
580 	iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality), &(buf[count]), 1);
581 	wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
582 	if ((status & TPM_STS_DATA_EXPECT) != 0) {
583 		rc = -EIO;
584 		goto out_err;
585 	}
586 
587 	/* go and do it */
588 	iic_tpm_write(TPM_STS(tpm_dev.locality), &sts, 1);
589 
590 	return len;
591 out_err:
592 	tpm_tis_i2c_ready(chip);
593 	/* The TPM needs some time to clean up here,
594 	 * so we sleep rather than keeping the bus busy
595 	 */
596 	usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
597 	release_locality(chip, tpm_dev.locality, 0);
598 	return rc;
599 }
600 
601 static bool tpm_tis_i2c_req_canceled(struct tpm_chip *chip, u8 status)
602 {
603 	return (status == TPM_STS_COMMAND_READY);
604 }
605 
606 static const struct tpm_class_ops tpm_tis_i2c = {
607 	.flags = TPM_OPS_AUTO_STARTUP,
608 	.status = tpm_tis_i2c_status,
609 	.recv = tpm_tis_i2c_recv,
610 	.send = tpm_tis_i2c_send,
611 	.cancel = tpm_tis_i2c_ready,
612 	.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
613 	.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
614 	.req_canceled = tpm_tis_i2c_req_canceled,
615 };
616 
617 static int tpm_tis_i2c_init(struct device *dev)
618 {
619 	u32 vendor;
620 	int rc = 0;
621 	struct tpm_chip *chip;
622 
623 	chip = tpmm_chip_alloc(dev, &tpm_tis_i2c);
624 	if (IS_ERR(chip))
625 		return PTR_ERR(chip);
626 
627 	/* Default timeouts */
628 	chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
629 	chip->timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
630 	chip->timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
631 	chip->timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
632 
633 	if (request_locality(chip, 0) != 0) {
634 		dev_err(dev, "could not request locality\n");
635 		rc = -ENODEV;
636 		goto out_err;
637 	}
638 
639 	/* read four bytes from DID_VID register */
640 	if (iic_tpm_read(TPM_DID_VID(0), (u8 *)&vendor, 4) < 0) {
641 		dev_err(dev, "could not read vendor id\n");
642 		rc = -EIO;
643 		goto out_release;
644 	}
645 
646 	if (vendor == TPM_TIS_I2C_DID_VID_9645) {
647 		tpm_dev.chip_type = SLB9645;
648 	} else if (vendor == TPM_TIS_I2C_DID_VID_9635) {
649 		tpm_dev.chip_type = SLB9635;
650 	} else {
651 		dev_err(dev, "vendor id did not match! ID was %08x\n", vendor);
652 		rc = -ENODEV;
653 		goto out_release;
654 	}
655 
656 	dev_info(dev, "1.2 TPM (device-id 0x%X)\n", vendor >> 16);
657 
658 	tpm_dev.chip = chip;
659 
660 	return tpm_chip_register(chip);
661 out_release:
662 	release_locality(chip, tpm_dev.locality, 1);
663 	tpm_dev.client = NULL;
664 out_err:
665 	return rc;
666 }
667 
668 static const struct i2c_device_id tpm_tis_i2c_table[] = {
669 	{"tpm_i2c_infineon"},
670 	{"slb9635tt"},
671 	{"slb9645tt"},
672 	{},
673 };
674 
675 MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_table);
676 
677 #ifdef CONFIG_OF
678 static const struct of_device_id tpm_tis_i2c_of_match[] = {
679 	{.compatible = "infineon,tpm_i2c_infineon"},
680 	{.compatible = "infineon,slb9635tt"},
681 	{.compatible = "infineon,slb9645tt"},
682 	{},
683 };
684 MODULE_DEVICE_TABLE(of, tpm_tis_i2c_of_match);
685 #endif
686 
687 static SIMPLE_DEV_PM_OPS(tpm_tis_i2c_ops, tpm_pm_suspend, tpm_pm_resume);
688 
689 static int tpm_tis_i2c_probe(struct i2c_client *client,
690 			     const struct i2c_device_id *id)
691 {
692 	int rc;
693 	struct device *dev = &(client->dev);
694 
695 	if (tpm_dev.client != NULL) {
696 		dev_err(dev, "This driver only supports one client at a time\n");
697 		return -EBUSY;	/* We only support one client */
698 	}
699 
700 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
701 		dev_err(dev, "no algorithms associated to the i2c bus\n");
702 		return -ENODEV;
703 	}
704 
705 	tpm_dev.client = client;
706 	rc = tpm_tis_i2c_init(&client->dev);
707 	if (rc != 0) {
708 		tpm_dev.client = NULL;
709 		rc = -ENODEV;
710 	}
711 	return rc;
712 }
713 
714 static int tpm_tis_i2c_remove(struct i2c_client *client)
715 {
716 	struct tpm_chip *chip = tpm_dev.chip;
717 
718 	tpm_chip_unregister(chip);
719 	release_locality(chip, tpm_dev.locality, 1);
720 	tpm_dev.client = NULL;
721 
722 	return 0;
723 }
724 
725 static struct i2c_driver tpm_tis_i2c_driver = {
726 	.id_table = tpm_tis_i2c_table,
727 	.probe = tpm_tis_i2c_probe,
728 	.remove = tpm_tis_i2c_remove,
729 	.driver = {
730 		   .name = "tpm_i2c_infineon",
731 		   .pm = &tpm_tis_i2c_ops,
732 		   .of_match_table = of_match_ptr(tpm_tis_i2c_of_match),
733 		   },
734 };
735 
736 module_i2c_driver(tpm_tis_i2c_driver);
737 MODULE_AUTHOR("Peter Huewe <peter.huewe@infineon.com>");
738 MODULE_DESCRIPTION("TPM TIS I2C Infineon Driver");
739 MODULE_VERSION("2.2.0");
740 MODULE_LICENSE("GPL");
741