1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2012,2013 Infineon Technologies
4  *
5  * Authors:
6  * Peter Huewe <peter.huewe@infineon.com>
7  *
8  * Device driver for TCG/TCPA TPM (trusted platform module).
9  * Specifications at www.trustedcomputinggroup.org
10  *
11  * This device driver implements the TPM interface as defined in
12  * the TCG TPM Interface Spec version 1.2, revision 1.0 and the
13  * Infineon I2C Protocol Stack Specification v0.20.
14  *
15  * It is based on the original tpm_tis device driver from Leendert van
16  * Dorn and Kyleen Hall.
17  */
18 #include <linux/i2c.h>
19 #include <linux/module.h>
20 #include <linux/wait.h>
21 #include "tpm.h"
22 
23 #define TPM_I2C_INFINEON_BUFSIZE 1260
24 
25 /* max. number of iterations after I2C NAK */
26 #define MAX_COUNT 3
27 
28 #define SLEEP_DURATION_LOW 55
29 #define SLEEP_DURATION_HI 65
30 
31 /* max. number of iterations after I2C NAK for 'long' commands
32  * we need this especially for sending TPM_READY, since the cleanup after the
33  * transtion to the ready state may take some time, but it is unpredictable
34  * how long it will take.
35  */
36 #define MAX_COUNT_LONG 50
37 
38 #define SLEEP_DURATION_LONG_LOW 200
39 #define SLEEP_DURATION_LONG_HI 220
40 
41 /* After sending TPM_READY to 'reset' the TPM we have to sleep even longer */
42 #define SLEEP_DURATION_RESET_LOW 2400
43 #define SLEEP_DURATION_RESET_HI 2600
44 
45 /* we want to use usleep_range instead of msleep for the 5ms TPM_TIMEOUT */
46 #define TPM_TIMEOUT_US_LOW (TPM_TIMEOUT * 1000)
47 #define TPM_TIMEOUT_US_HI  (TPM_TIMEOUT_US_LOW + 2000)
48 
49 /* expected value for DIDVID register */
50 #define TPM_TIS_I2C_DID_VID_9635 0xd1150b00L
51 #define TPM_TIS_I2C_DID_VID_9645 0x001a15d1L
52 
53 enum i2c_chip_type {
54 	SLB9635,
55 	SLB9645,
56 	UNKNOWN,
57 };
58 
59 struct tpm_inf_dev {
60 	struct i2c_client *client;
61 	int locality;
62 	/* In addition to the data itself, the buffer must fit the 7-bit I2C
63 	 * address and the direction bit.
64 	 */
65 	u8 buf[TPM_I2C_INFINEON_BUFSIZE + 1];
66 	struct tpm_chip *chip;
67 	enum i2c_chip_type chip_type;
68 	unsigned int adapterlimit;
69 };
70 
71 static struct tpm_inf_dev tpm_dev;
72 
73 /*
74  * iic_tpm_read() - read from TPM register
75  * @addr: register address to read from
76  * @buffer: provided by caller
77  * @len: number of bytes to read
78  *
79  * Read len bytes from TPM register and put them into
80  * buffer (little-endian format, i.e. first byte is put into buffer[0]).
81  *
82  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
83  * values have to be swapped.
84  *
85  * NOTE: We can't unfortunately use the combined read/write functions
86  * provided by the i2c core as the TPM currently does not support the
87  * repeated start condition and due to it's special requirements.
88  * The i2c_smbus* functions do not work for this chip.
89  *
90  * Return -EIO on error, 0 on success.
91  */
92 static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
93 {
94 
95 	struct i2c_msg msg1 = {
96 		.addr = tpm_dev.client->addr,
97 		.len = 1,
98 		.buf = &addr
99 	};
100 	struct i2c_msg msg2 = {
101 		.addr = tpm_dev.client->addr,
102 		.flags = I2C_M_RD,
103 		.len = len,
104 		.buf = buffer
105 	};
106 	struct i2c_msg msgs[] = {msg1, msg2};
107 
108 	int rc = 0;
109 	int count;
110 	unsigned int msglen = len;
111 
112 	/* Lock the adapter for the duration of the whole sequence. */
113 	if (!tpm_dev.client->adapter->algo->master_xfer)
114 		return -EOPNOTSUPP;
115 	i2c_lock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);
116 
117 	if (tpm_dev.chip_type == SLB9645) {
118 		/* use a combined read for newer chips
119 		 * unfortunately the smbus functions are not suitable due to
120 		 * the 32 byte limit of the smbus.
121 		 * retries should usually not be needed, but are kept just to
122 		 * be on the safe side.
123 		 */
124 		for (count = 0; count < MAX_COUNT; count++) {
125 			rc = __i2c_transfer(tpm_dev.client->adapter, msgs, 2);
126 			if (rc > 0)
127 				break;	/* break here to skip sleep */
128 			usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
129 		}
130 	} else {
131 		/* Expect to send one command message and one data message, but
132 		 * support looping over each or both if necessary.
133 		 */
134 		while (len > 0) {
135 			/* slb9635 protocol should work in all cases */
136 			for (count = 0; count < MAX_COUNT; count++) {
137 				rc = __i2c_transfer(tpm_dev.client->adapter,
138 						    &msg1, 1);
139 				if (rc > 0)
140 					break;	/* break here to skip sleep */
141 
142 				usleep_range(SLEEP_DURATION_LOW,
143 					     SLEEP_DURATION_HI);
144 			}
145 
146 			if (rc <= 0)
147 				goto out;
148 
149 			/* After the TPM has successfully received the register
150 			 * address it needs some time, thus we're sleeping here
151 			 * again, before retrieving the data
152 			 */
153 			for (count = 0; count < MAX_COUNT; count++) {
154 				if (tpm_dev.adapterlimit) {
155 					msglen = min_t(unsigned int,
156 						       tpm_dev.adapterlimit,
157 						       len);
158 					msg2.len = msglen;
159 				}
160 				usleep_range(SLEEP_DURATION_LOW,
161 					     SLEEP_DURATION_HI);
162 				rc = __i2c_transfer(tpm_dev.client->adapter,
163 						    &msg2, 1);
164 				if (rc > 0) {
165 					/* Since len is unsigned, make doubly
166 					 * sure we do not underflow it.
167 					 */
168 					if (msglen > len)
169 						len = 0;
170 					else
171 						len -= msglen;
172 					msg2.buf += msglen;
173 					break;
174 				}
175 				/* If the I2C adapter rejected the request (e.g
176 				 * when the quirk read_max_len < len) fall back
177 				 * to a sane minimum value and try again.
178 				 */
179 				if (rc == -EOPNOTSUPP)
180 					tpm_dev.adapterlimit =
181 							I2C_SMBUS_BLOCK_MAX;
182 			}
183 
184 			if (rc <= 0)
185 				goto out;
186 		}
187 	}
188 
189 out:
190 	i2c_unlock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);
191 	/* take care of 'guard time' */
192 	usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
193 
194 	/* __i2c_transfer returns the number of successfully transferred
195 	 * messages.
196 	 * So rc should be greater than 0 here otherwise we have an error.
197 	 */
198 	if (rc <= 0)
199 		return -EIO;
200 
201 	return 0;
202 }
203 
204 static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
205 				 unsigned int sleep_low,
206 				 unsigned int sleep_hi, u8 max_count)
207 {
208 	int rc = -EIO;
209 	int count;
210 
211 	struct i2c_msg msg1 = {
212 		.addr = tpm_dev.client->addr,
213 		.len = len + 1,
214 		.buf = tpm_dev.buf
215 	};
216 
217 	if (len > TPM_I2C_INFINEON_BUFSIZE)
218 		return -EINVAL;
219 
220 	if (!tpm_dev.client->adapter->algo->master_xfer)
221 		return -EOPNOTSUPP;
222 	i2c_lock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);
223 
224 	/* prepend the 'register address' to the buffer */
225 	tpm_dev.buf[0] = addr;
226 	memcpy(&(tpm_dev.buf[1]), buffer, len);
227 
228 	/*
229 	 * NOTE: We have to use these special mechanisms here and unfortunately
230 	 * cannot rely on the standard behavior of i2c_transfer.
231 	 * Even for newer chips the smbus functions are not
232 	 * suitable due to the 32 byte limit of the smbus.
233 	 */
234 	for (count = 0; count < max_count; count++) {
235 		rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
236 		if (rc > 0)
237 			break;
238 		usleep_range(sleep_low, sleep_hi);
239 	}
240 
241 	i2c_unlock_bus(tpm_dev.client->adapter, I2C_LOCK_SEGMENT);
242 	/* take care of 'guard time' */
243 	usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
244 
245 	/* __i2c_transfer returns the number of successfully transferred
246 	 * messages.
247 	 * So rc should be greater than 0 here otherwise we have an error.
248 	 */
249 	if (rc <= 0)
250 		return -EIO;
251 
252 	return 0;
253 }
254 
255 /*
256  * iic_tpm_write() - write to TPM register
257  * @addr: register address to write to
258  * @buffer: containing data to be written
259  * @len: number of bytes to write
260  *
261  * Write len bytes from provided buffer to TPM register (little
262  * endian format, i.e. buffer[0] is written as first byte).
263  *
264  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
265  * values have to be swapped.
266  *
267  * NOTE: use this function instead of the iic_tpm_write_generic function.
268  *
269  * Return -EIO on error, 0 on success
270  */
271 static int iic_tpm_write(u8 addr, u8 *buffer, size_t len)
272 {
273 	return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LOW,
274 				     SLEEP_DURATION_HI, MAX_COUNT);
275 }
276 
277 /*
278  * This function is needed especially for the cleanup situation after
279  * sending TPM_READY
280  * */
281 static int iic_tpm_write_long(u8 addr, u8 *buffer, size_t len)
282 {
283 	return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LONG_LOW,
284 				     SLEEP_DURATION_LONG_HI, MAX_COUNT_LONG);
285 }
286 
287 enum tis_access {
288 	TPM_ACCESS_VALID = 0x80,
289 	TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
290 	TPM_ACCESS_REQUEST_PENDING = 0x04,
291 	TPM_ACCESS_REQUEST_USE = 0x02,
292 };
293 
294 enum tis_status {
295 	TPM_STS_VALID = 0x80,
296 	TPM_STS_COMMAND_READY = 0x40,
297 	TPM_STS_GO = 0x20,
298 	TPM_STS_DATA_AVAIL = 0x10,
299 	TPM_STS_DATA_EXPECT = 0x08,
300 };
301 
302 enum tis_defaults {
303 	TIS_SHORT_TIMEOUT = 750,	/* ms */
304 	TIS_LONG_TIMEOUT = 2000,	/* 2 sec */
305 };
306 
307 #define	TPM_ACCESS(l)			(0x0000 | ((l) << 4))
308 #define	TPM_STS(l)			(0x0001 | ((l) << 4))
309 #define	TPM_DATA_FIFO(l)		(0x0005 | ((l) << 4))
310 #define	TPM_DID_VID(l)			(0x0006 | ((l) << 4))
311 
312 static bool check_locality(struct tpm_chip *chip, int loc)
313 {
314 	u8 buf;
315 	int rc;
316 
317 	rc = iic_tpm_read(TPM_ACCESS(loc), &buf, 1);
318 	if (rc < 0)
319 		return false;
320 
321 	if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
322 	    (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
323 		tpm_dev.locality = loc;
324 		return true;
325 	}
326 
327 	return false;
328 }
329 
330 /* implementation similar to tpm_tis */
331 static void release_locality(struct tpm_chip *chip, int loc, int force)
332 {
333 	u8 buf;
334 	if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0)
335 		return;
336 
337 	if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
338 	    (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) {
339 		buf = TPM_ACCESS_ACTIVE_LOCALITY;
340 		iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
341 	}
342 }
343 
344 static int request_locality(struct tpm_chip *chip, int loc)
345 {
346 	unsigned long stop;
347 	u8 buf = TPM_ACCESS_REQUEST_USE;
348 
349 	if (check_locality(chip, loc))
350 		return loc;
351 
352 	iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
353 
354 	/* wait for burstcount */
355 	stop = jiffies + chip->timeout_a;
356 	do {
357 		if (check_locality(chip, loc))
358 			return loc;
359 		usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
360 	} while (time_before(jiffies, stop));
361 
362 	return -ETIME;
363 }
364 
365 static u8 tpm_tis_i2c_status(struct tpm_chip *chip)
366 {
367 	/* NOTE: since I2C read may fail, return 0 in this case --> time-out */
368 	u8 buf = 0xFF;
369 	u8 i = 0;
370 
371 	do {
372 		if (iic_tpm_read(TPM_STS(tpm_dev.locality), &buf, 1) < 0)
373 			return 0;
374 
375 		i++;
376 	/* if locallity is set STS should not be 0xFF */
377 	} while ((buf == 0xFF) && i < 10);
378 
379 	return buf;
380 }
381 
382 static void tpm_tis_i2c_ready(struct tpm_chip *chip)
383 {
384 	/* this causes the current command to be aborted */
385 	u8 buf = TPM_STS_COMMAND_READY;
386 	iic_tpm_write_long(TPM_STS(tpm_dev.locality), &buf, 1);
387 }
388 
389 static ssize_t get_burstcount(struct tpm_chip *chip)
390 {
391 	unsigned long stop;
392 	ssize_t burstcnt;
393 	u8 buf[3];
394 
395 	/* wait for burstcount */
396 	/* which timeout value, spec has 2 answers (c & d) */
397 	stop = jiffies + chip->timeout_d;
398 	do {
399 		/* Note: STS is little endian */
400 		if (iic_tpm_read(TPM_STS(tpm_dev.locality)+1, buf, 3) < 0)
401 			burstcnt = 0;
402 		else
403 			burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0];
404 
405 		if (burstcnt)
406 			return burstcnt;
407 
408 		usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
409 	} while (time_before(jiffies, stop));
410 	return -EBUSY;
411 }
412 
413 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
414 			 int *status)
415 {
416 	unsigned long stop;
417 
418 	/* check current status */
419 	*status = tpm_tis_i2c_status(chip);
420 	if ((*status != 0xFF) && (*status & mask) == mask)
421 		return 0;
422 
423 	stop = jiffies + timeout;
424 	do {
425 		/* since we just checked the status, give the TPM some time */
426 		usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
427 		*status = tpm_tis_i2c_status(chip);
428 		if ((*status & mask) == mask)
429 			return 0;
430 
431 	} while (time_before(jiffies, stop));
432 
433 	return -ETIME;
434 }
435 
436 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
437 {
438 	size_t size = 0;
439 	ssize_t burstcnt;
440 	u8 retries = 0;
441 	int rc;
442 
443 	while (size < count) {
444 		burstcnt = get_burstcount(chip);
445 
446 		/* burstcnt < 0 = TPM is busy */
447 		if (burstcnt < 0)
448 			return burstcnt;
449 
450 		/* limit received data to max. left */
451 		if (burstcnt > (count - size))
452 			burstcnt = count - size;
453 
454 		rc = iic_tpm_read(TPM_DATA_FIFO(tpm_dev.locality),
455 				  &(buf[size]), burstcnt);
456 		if (rc == 0)
457 			size += burstcnt;
458 		else if (rc < 0)
459 			retries++;
460 
461 		/* avoid endless loop in case of broken HW */
462 		if (retries > MAX_COUNT_LONG)
463 			return -EIO;
464 	}
465 	return size;
466 }
467 
468 static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
469 {
470 	int size = 0;
471 	int status;
472 	u32 expected;
473 
474 	if (count < TPM_HEADER_SIZE) {
475 		size = -EIO;
476 		goto out;
477 	}
478 
479 	/* read first 10 bytes, including tag, paramsize, and result */
480 	size = recv_data(chip, buf, TPM_HEADER_SIZE);
481 	if (size < TPM_HEADER_SIZE) {
482 		dev_err(&chip->dev, "Unable to read header\n");
483 		goto out;
484 	}
485 
486 	expected = be32_to_cpu(*(__be32 *)(buf + 2));
487 	if (((size_t) expected > count) || (expected < TPM_HEADER_SIZE)) {
488 		size = -EIO;
489 		goto out;
490 	}
491 
492 	size += recv_data(chip, &buf[TPM_HEADER_SIZE],
493 			  expected - TPM_HEADER_SIZE);
494 	if (size < expected) {
495 		dev_err(&chip->dev, "Unable to read remainder of result\n");
496 		size = -ETIME;
497 		goto out;
498 	}
499 
500 	wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
501 	if (status & TPM_STS_DATA_AVAIL) {	/* retry? */
502 		dev_err(&chip->dev, "Error left over data\n");
503 		size = -EIO;
504 		goto out;
505 	}
506 
507 out:
508 	tpm_tis_i2c_ready(chip);
509 	/* The TPM needs some time to clean up here,
510 	 * so we sleep rather than keeping the bus busy
511 	 */
512 	usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
513 	release_locality(chip, tpm_dev.locality, 0);
514 	return size;
515 }
516 
517 static int tpm_tis_i2c_send(struct tpm_chip *chip, u8 *buf, size_t len)
518 {
519 	int rc, status;
520 	ssize_t burstcnt;
521 	size_t count = 0;
522 	u8 retries = 0;
523 	u8 sts = TPM_STS_GO;
524 
525 	if (len > TPM_I2C_INFINEON_BUFSIZE)
526 		return -E2BIG;
527 
528 	if (request_locality(chip, 0) < 0)
529 		return -EBUSY;
530 
531 	status = tpm_tis_i2c_status(chip);
532 	if ((status & TPM_STS_COMMAND_READY) == 0) {
533 		tpm_tis_i2c_ready(chip);
534 		if (wait_for_stat
535 		    (chip, TPM_STS_COMMAND_READY,
536 		     chip->timeout_b, &status) < 0) {
537 			rc = -ETIME;
538 			goto out_err;
539 		}
540 	}
541 
542 	while (count < len - 1) {
543 		burstcnt = get_burstcount(chip);
544 
545 		/* burstcnt < 0 = TPM is busy */
546 		if (burstcnt < 0)
547 			return burstcnt;
548 
549 		if (burstcnt > (len - 1 - count))
550 			burstcnt = len - 1 - count;
551 
552 		rc = iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality),
553 				   &(buf[count]), burstcnt);
554 		if (rc == 0)
555 			count += burstcnt;
556 		else if (rc < 0)
557 			retries++;
558 
559 		/* avoid endless loop in case of broken HW */
560 		if (retries > MAX_COUNT_LONG) {
561 			rc = -EIO;
562 			goto out_err;
563 		}
564 
565 		wait_for_stat(chip, TPM_STS_VALID,
566 			      chip->timeout_c, &status);
567 
568 		if ((status & TPM_STS_DATA_EXPECT) == 0) {
569 			rc = -EIO;
570 			goto out_err;
571 		}
572 	}
573 
574 	/* write last byte */
575 	iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality), &(buf[count]), 1);
576 	wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
577 	if ((status & TPM_STS_DATA_EXPECT) != 0) {
578 		rc = -EIO;
579 		goto out_err;
580 	}
581 
582 	/* go and do it */
583 	iic_tpm_write(TPM_STS(tpm_dev.locality), &sts, 1);
584 
585 	return 0;
586 out_err:
587 	tpm_tis_i2c_ready(chip);
588 	/* The TPM needs some time to clean up here,
589 	 * so we sleep rather than keeping the bus busy
590 	 */
591 	usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
592 	release_locality(chip, tpm_dev.locality, 0);
593 	return rc;
594 }
595 
596 static bool tpm_tis_i2c_req_canceled(struct tpm_chip *chip, u8 status)
597 {
598 	return (status == TPM_STS_COMMAND_READY);
599 }
600 
601 static const struct tpm_class_ops tpm_tis_i2c = {
602 	.flags = TPM_OPS_AUTO_STARTUP,
603 	.status = tpm_tis_i2c_status,
604 	.recv = tpm_tis_i2c_recv,
605 	.send = tpm_tis_i2c_send,
606 	.cancel = tpm_tis_i2c_ready,
607 	.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
608 	.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
609 	.req_canceled = tpm_tis_i2c_req_canceled,
610 };
611 
612 static int tpm_tis_i2c_init(struct device *dev)
613 {
614 	u32 vendor;
615 	int rc = 0;
616 	struct tpm_chip *chip;
617 
618 	chip = tpmm_chip_alloc(dev, &tpm_tis_i2c);
619 	if (IS_ERR(chip))
620 		return PTR_ERR(chip);
621 
622 	/* Default timeouts */
623 	chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
624 	chip->timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
625 	chip->timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
626 	chip->timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
627 
628 	if (request_locality(chip, 0) != 0) {
629 		dev_err(dev, "could not request locality\n");
630 		rc = -ENODEV;
631 		goto out_err;
632 	}
633 
634 	/* read four bytes from DID_VID register */
635 	if (iic_tpm_read(TPM_DID_VID(0), (u8 *)&vendor, 4) < 0) {
636 		dev_err(dev, "could not read vendor id\n");
637 		rc = -EIO;
638 		goto out_release;
639 	}
640 
641 	if (vendor == TPM_TIS_I2C_DID_VID_9645) {
642 		tpm_dev.chip_type = SLB9645;
643 	} else if (vendor == TPM_TIS_I2C_DID_VID_9635) {
644 		tpm_dev.chip_type = SLB9635;
645 	} else {
646 		dev_err(dev, "vendor id did not match! ID was %08x\n", vendor);
647 		rc = -ENODEV;
648 		goto out_release;
649 	}
650 
651 	dev_info(dev, "1.2 TPM (device-id 0x%X)\n", vendor >> 16);
652 
653 	tpm_dev.chip = chip;
654 
655 	return tpm_chip_register(chip);
656 out_release:
657 	release_locality(chip, tpm_dev.locality, 1);
658 	tpm_dev.client = NULL;
659 out_err:
660 	return rc;
661 }
662 
663 static const struct i2c_device_id tpm_tis_i2c_table[] = {
664 	{"tpm_i2c_infineon"},
665 	{"slb9635tt"},
666 	{"slb9645tt"},
667 	{},
668 };
669 
670 MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_table);
671 
672 #ifdef CONFIG_OF
673 static const struct of_device_id tpm_tis_i2c_of_match[] = {
674 	{.compatible = "infineon,tpm_i2c_infineon"},
675 	{.compatible = "infineon,slb9635tt"},
676 	{.compatible = "infineon,slb9645tt"},
677 	{},
678 };
679 MODULE_DEVICE_TABLE(of, tpm_tis_i2c_of_match);
680 #endif
681 
682 static SIMPLE_DEV_PM_OPS(tpm_tis_i2c_ops, tpm_pm_suspend, tpm_pm_resume);
683 
684 static int tpm_tis_i2c_probe(struct i2c_client *client,
685 			     const struct i2c_device_id *id)
686 {
687 	int rc;
688 	struct device *dev = &(client->dev);
689 
690 	if (tpm_dev.client != NULL) {
691 		dev_err(dev, "This driver only supports one client at a time\n");
692 		return -EBUSY;	/* We only support one client */
693 	}
694 
695 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
696 		dev_err(dev, "no algorithms associated to the i2c bus\n");
697 		return -ENODEV;
698 	}
699 
700 	tpm_dev.client = client;
701 	rc = tpm_tis_i2c_init(&client->dev);
702 	if (rc != 0) {
703 		tpm_dev.client = NULL;
704 		rc = -ENODEV;
705 	}
706 	return rc;
707 }
708 
709 static int tpm_tis_i2c_remove(struct i2c_client *client)
710 {
711 	struct tpm_chip *chip = tpm_dev.chip;
712 
713 	tpm_chip_unregister(chip);
714 	release_locality(chip, tpm_dev.locality, 1);
715 	tpm_dev.client = NULL;
716 
717 	return 0;
718 }
719 
720 static struct i2c_driver tpm_tis_i2c_driver = {
721 	.id_table = tpm_tis_i2c_table,
722 	.probe = tpm_tis_i2c_probe,
723 	.remove = tpm_tis_i2c_remove,
724 	.driver = {
725 		   .name = "tpm_i2c_infineon",
726 		   .pm = &tpm_tis_i2c_ops,
727 		   .of_match_table = of_match_ptr(tpm_tis_i2c_of_match),
728 		   },
729 };
730 
731 module_i2c_driver(tpm_tis_i2c_driver);
732 MODULE_AUTHOR("Peter Huewe <peter.huewe@infineon.com>");
733 MODULE_DESCRIPTION("TPM TIS I2C Infineon Driver");
734 MODULE_VERSION("2.2.0");
735 MODULE_LICENSE("GPL");
736