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