xref: /linux/drivers/char/tpm/st33zp24/st33zp24.c (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732)
1 /*
2  * STMicroelectronics TPM Linux driver for TPM ST33ZP24
3  * Copyright (C) 2009 - 2015 STMicroelectronics
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
17  */
18 
19 #include <linux/module.h>
20 #include <linux/fs.h>
21 #include <linux/miscdevice.h>
22 #include <linux/kernel.h>
23 #include <linux/delay.h>
24 #include <linux/wait.h>
25 #include <linux/freezer.h>
26 #include <linux/string.h>
27 #include <linux/interrupt.h>
28 #include <linux/gpio.h>
29 #include <linux/sched.h>
30 #include <linux/uaccess.h>
31 #include <linux/io.h>
32 #include <linux/slab.h>
33 
34 #include "../tpm.h"
35 #include "st33zp24.h"
36 
37 #define TPM_ACCESS			0x0
38 #define TPM_STS				0x18
39 #define TPM_DATA_FIFO			0x24
40 #define TPM_INTF_CAPABILITY		0x14
41 #define TPM_INT_STATUS			0x10
42 #define TPM_INT_ENABLE			0x08
43 
44 #define LOCALITY0			0
45 
46 enum st33zp24_access {
47 	TPM_ACCESS_VALID = 0x80,
48 	TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
49 	TPM_ACCESS_REQUEST_PENDING = 0x04,
50 	TPM_ACCESS_REQUEST_USE = 0x02,
51 };
52 
53 enum st33zp24_status {
54 	TPM_STS_VALID = 0x80,
55 	TPM_STS_COMMAND_READY = 0x40,
56 	TPM_STS_GO = 0x20,
57 	TPM_STS_DATA_AVAIL = 0x10,
58 	TPM_STS_DATA_EXPECT = 0x08,
59 };
60 
61 enum st33zp24_int_flags {
62 	TPM_GLOBAL_INT_ENABLE = 0x80,
63 	TPM_INTF_CMD_READY_INT = 0x080,
64 	TPM_INTF_FIFO_AVALAIBLE_INT = 0x040,
65 	TPM_INTF_WAKE_UP_READY_INT = 0x020,
66 	TPM_INTF_LOCALITY_CHANGE_INT = 0x004,
67 	TPM_INTF_STS_VALID_INT = 0x002,
68 	TPM_INTF_DATA_AVAIL_INT = 0x001,
69 };
70 
71 enum tis_defaults {
72 	TIS_SHORT_TIMEOUT = 750,
73 	TIS_LONG_TIMEOUT = 2000,
74 };
75 
76 struct st33zp24_dev {
77 	struct tpm_chip *chip;
78 	void *phy_id;
79 	const struct st33zp24_phy_ops *ops;
80 	u32 intrs;
81 	int io_lpcpd;
82 };
83 
84 /*
85  * clear_interruption clear the pending interrupt.
86  * @param: tpm_dev, the tpm device device.
87  * @return: the interrupt status value.
88  */
89 static u8 clear_interruption(struct st33zp24_dev *tpm_dev)
90 {
91 	u8 interrupt;
92 
93 	tpm_dev->ops->recv(tpm_dev->phy_id, TPM_INT_STATUS, &interrupt, 1);
94 	tpm_dev->ops->send(tpm_dev->phy_id, TPM_INT_STATUS, &interrupt, 1);
95 	return interrupt;
96 } /* clear_interruption() */
97 
98 /*
99  * st33zp24_cancel, cancel the current command execution or
100  * set STS to COMMAND READY.
101  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h
102  */
103 static void st33zp24_cancel(struct tpm_chip *chip)
104 {
105 	struct st33zp24_dev *tpm_dev;
106 	u8 data;
107 
108 	tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
109 
110 	data = TPM_STS_COMMAND_READY;
111 	tpm_dev->ops->send(tpm_dev->phy_id, TPM_STS, &data, 1);
112 } /* st33zp24_cancel() */
113 
114 /*
115  * st33zp24_status return the TPM_STS register
116  * @param: chip, the tpm chip description
117  * @return: the TPM_STS register value.
118  */
119 static u8 st33zp24_status(struct tpm_chip *chip)
120 {
121 	struct st33zp24_dev *tpm_dev;
122 	u8 data;
123 
124 	tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
125 
126 	tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS, &data, 1);
127 	return data;
128 } /* st33zp24_status() */
129 
130 /*
131  * check_locality if the locality is active
132  * @param: chip, the tpm chip description
133  * @return: the active locality or -EACCESS.
134  */
135 static int check_locality(struct tpm_chip *chip)
136 {
137 	struct st33zp24_dev *tpm_dev;
138 	u8 data;
139 	u8 status;
140 
141 	tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
142 
143 	status = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
144 	if (status && (data &
145 		(TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
146 		(TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
147 		return chip->vendor.locality;
148 
149 	return -EACCES;
150 } /* check_locality() */
151 
152 /*
153  * request_locality request the TPM locality
154  * @param: chip, the chip description
155  * @return: the active locality or negative value.
156  */
157 static int request_locality(struct tpm_chip *chip)
158 {
159 	unsigned long stop;
160 	long ret;
161 	struct st33zp24_dev *tpm_dev;
162 	u8 data;
163 
164 	if (check_locality(chip) == chip->vendor.locality)
165 		return chip->vendor.locality;
166 
167 	tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
168 
169 	data = TPM_ACCESS_REQUEST_USE;
170 	ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
171 	if (ret < 0)
172 		return ret;
173 
174 	stop = jiffies + chip->vendor.timeout_a;
175 
176 	/* Request locality is usually effective after the request */
177 	do {
178 		if (check_locality(chip) >= 0)
179 			return chip->vendor.locality;
180 		msleep(TPM_TIMEOUT);
181 	} while (time_before(jiffies, stop));
182 
183 	/* could not get locality */
184 	return -EACCES;
185 } /* request_locality() */
186 
187 /*
188  * release_locality release the active locality
189  * @param: chip, the tpm chip description.
190  */
191 static void release_locality(struct tpm_chip *chip)
192 {
193 	struct st33zp24_dev *tpm_dev;
194 	u8 data;
195 
196 	tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
197 	data = TPM_ACCESS_ACTIVE_LOCALITY;
198 
199 	tpm_dev->ops->send(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
200 }
201 
202 /*
203  * get_burstcount return the burstcount value
204  * @param: chip, the chip description
205  * return: the burstcount or negative value.
206  */
207 static int get_burstcount(struct tpm_chip *chip)
208 {
209 	unsigned long stop;
210 	int burstcnt, status;
211 	u8 tpm_reg, temp;
212 	struct st33zp24_dev *tpm_dev;
213 
214 	tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
215 
216 	stop = jiffies + chip->vendor.timeout_d;
217 	do {
218 		tpm_reg = TPM_STS + 1;
219 		status = tpm_dev->ops->recv(tpm_dev->phy_id, tpm_reg, &temp, 1);
220 		if (status < 0)
221 			return -EBUSY;
222 
223 		tpm_reg = TPM_STS + 2;
224 		burstcnt = temp;
225 		status = tpm_dev->ops->recv(tpm_dev->phy_id, tpm_reg, &temp, 1);
226 		if (status < 0)
227 			return -EBUSY;
228 
229 		burstcnt |= temp << 8;
230 		if (burstcnt)
231 			return burstcnt;
232 		msleep(TPM_TIMEOUT);
233 	} while (time_before(jiffies, stop));
234 	return -EBUSY;
235 } /* get_burstcount() */
236 
237 
238 /*
239  * wait_for_tpm_stat_cond
240  * @param: chip, chip description
241  * @param: mask, expected mask value
242  * @param: check_cancel, does the command expected to be canceled ?
243  * @param: canceled, did we received a cancel request ?
244  * @return: true if status == mask or if the command is canceled.
245  * false in other cases.
246  */
247 static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask,
248 				bool check_cancel, bool *canceled)
249 {
250 	u8 status = chip->ops->status(chip);
251 
252 	*canceled = false;
253 	if ((status & mask) == mask)
254 		return true;
255 	if (check_cancel && chip->ops->req_canceled(chip, status)) {
256 		*canceled = true;
257 		return true;
258 	}
259 	return false;
260 }
261 
262 /*
263  * wait_for_stat wait for a TPM_STS value
264  * @param: chip, the tpm chip description
265  * @param: mask, the value mask to wait
266  * @param: timeout, the timeout
267  * @param: queue, the wait queue.
268  * @param: check_cancel, does the command can be cancelled ?
269  * @return: the tpm status, 0 if success, -ETIME if timeout is reached.
270  */
271 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
272 			wait_queue_head_t *queue, bool check_cancel)
273 {
274 	unsigned long stop;
275 	int ret = 0;
276 	bool canceled = false;
277 	bool condition;
278 	u32 cur_intrs;
279 	u8 status;
280 	struct st33zp24_dev *tpm_dev;
281 
282 	tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
283 
284 	/* check current status */
285 	status = st33zp24_status(chip);
286 	if ((status & mask) == mask)
287 		return 0;
288 
289 	stop = jiffies + timeout;
290 
291 	if (chip->vendor.irq) {
292 		cur_intrs = tpm_dev->intrs;
293 		clear_interruption(tpm_dev);
294 		enable_irq(chip->vendor.irq);
295 
296 		do {
297 			if (ret == -ERESTARTSYS && freezing(current))
298 				clear_thread_flag(TIF_SIGPENDING);
299 
300 			timeout = stop - jiffies;
301 			if ((long) timeout <= 0)
302 				return -1;
303 
304 			ret = wait_event_interruptible_timeout(*queue,
305 						cur_intrs != tpm_dev->intrs,
306 						timeout);
307 			clear_interruption(tpm_dev);
308 			condition = wait_for_tpm_stat_cond(chip, mask,
309 						check_cancel, &canceled);
310 			if (ret >= 0 && condition) {
311 				if (canceled)
312 					return -ECANCELED;
313 				return 0;
314 			}
315 		} while (ret == -ERESTARTSYS && freezing(current));
316 
317 		disable_irq_nosync(chip->vendor.irq);
318 
319 	} else {
320 		do {
321 			msleep(TPM_TIMEOUT);
322 			status = chip->ops->status(chip);
323 			if ((status & mask) == mask)
324 				return 0;
325 		} while (time_before(jiffies, stop));
326 	}
327 
328 	return -ETIME;
329 } /* wait_for_stat() */
330 
331 /*
332  * recv_data receive data
333  * @param: chip, the tpm chip description
334  * @param: buf, the buffer where the data are received
335  * @param: count, the number of data to receive
336  * @return: the number of bytes read from TPM FIFO.
337  */
338 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
339 {
340 	int size = 0, burstcnt, len, ret;
341 	struct st33zp24_dev *tpm_dev;
342 
343 	tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
344 
345 	while (size < count &&
346 	       wait_for_stat(chip,
347 			     TPM_STS_DATA_AVAIL | TPM_STS_VALID,
348 			     chip->vendor.timeout_c,
349 			     &chip->vendor.read_queue, true) == 0) {
350 		burstcnt = get_burstcount(chip);
351 		if (burstcnt < 0)
352 			return burstcnt;
353 		len = min_t(int, burstcnt, count - size);
354 		ret = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_DATA_FIFO,
355 					 buf + size, len);
356 		if (ret < 0)
357 			return ret;
358 
359 		size += len;
360 	}
361 	return size;
362 }
363 
364 /*
365  * tpm_ioserirq_handler the serirq irq handler
366  * @param: irq, the tpm chip description
367  * @param: dev_id, the description of the chip
368  * @return: the status of the handler.
369  */
370 static irqreturn_t tpm_ioserirq_handler(int irq, void *dev_id)
371 {
372 	struct tpm_chip *chip = dev_id;
373 	struct st33zp24_dev *tpm_dev;
374 
375 	tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
376 
377 	tpm_dev->intrs++;
378 	wake_up_interruptible(&chip->vendor.read_queue);
379 	disable_irq_nosync(chip->vendor.irq);
380 
381 	return IRQ_HANDLED;
382 } /* tpm_ioserirq_handler() */
383 
384 /*
385  * st33zp24_send send TPM commands through the I2C bus.
386  *
387  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h
388  * @param: buf,	the buffer to send.
389  * @param: count, the number of bytes to send.
390  * @return: In case of success the number of bytes sent.
391  *			In other case, a < 0 value describing the issue.
392  */
393 static int st33zp24_send(struct tpm_chip *chip, unsigned char *buf,
394 			 size_t len)
395 {
396 	u32 status, i, size, ordinal;
397 	int burstcnt = 0;
398 	int ret;
399 	u8 data;
400 	struct st33zp24_dev *tpm_dev;
401 
402 	if (!chip)
403 		return -EBUSY;
404 	if (len < TPM_HEADER_SIZE)
405 		return -EBUSY;
406 
407 	tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
408 
409 	ret = request_locality(chip);
410 	if (ret < 0)
411 		return ret;
412 
413 	status = st33zp24_status(chip);
414 	if ((status & TPM_STS_COMMAND_READY) == 0) {
415 		st33zp24_cancel(chip);
416 		if (wait_for_stat
417 		    (chip, TPM_STS_COMMAND_READY, chip->vendor.timeout_b,
418 		     &chip->vendor.read_queue, false) < 0) {
419 			ret = -ETIME;
420 			goto out_err;
421 		}
422 	}
423 
424 	for (i = 0; i < len - 1;) {
425 		burstcnt = get_burstcount(chip);
426 		if (burstcnt < 0)
427 			return burstcnt;
428 		size = min_t(int, len - i - 1, burstcnt);
429 		ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_DATA_FIFO,
430 					 buf + i, size);
431 		if (ret < 0)
432 			goto out_err;
433 
434 		i += size;
435 	}
436 
437 	status = st33zp24_status(chip);
438 	if ((status & TPM_STS_DATA_EXPECT) == 0) {
439 		ret = -EIO;
440 		goto out_err;
441 	}
442 
443 	ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_DATA_FIFO,
444 				 buf + len - 1, 1);
445 	if (ret < 0)
446 		goto out_err;
447 
448 	status = st33zp24_status(chip);
449 	if ((status & TPM_STS_DATA_EXPECT) != 0) {
450 		ret = -EIO;
451 		goto out_err;
452 	}
453 
454 	data = TPM_STS_GO;
455 	ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_STS, &data, 1);
456 	if (ret < 0)
457 		goto out_err;
458 
459 	if (chip->vendor.irq) {
460 		ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
461 
462 		ret = wait_for_stat(chip, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
463 				tpm_calc_ordinal_duration(chip, ordinal),
464 				&chip->vendor.read_queue, false);
465 		if (ret < 0)
466 			goto out_err;
467 	}
468 
469 	return len;
470 out_err:
471 	st33zp24_cancel(chip);
472 	release_locality(chip);
473 	return ret;
474 }
475 
476 /*
477  * st33zp24_recv received TPM response through TPM phy.
478  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h.
479  * @param: buf,	the buffer to store datas.
480  * @param: count, the number of bytes to send.
481  * @return: In case of success the number of bytes received.
482  *	    In other case, a < 0 value describing the issue.
483  */
484 static int st33zp24_recv(struct tpm_chip *chip, unsigned char *buf,
485 			    size_t count)
486 {
487 	int size = 0;
488 	int expected;
489 
490 	if (!chip)
491 		return -EBUSY;
492 
493 	if (count < TPM_HEADER_SIZE) {
494 		size = -EIO;
495 		goto out;
496 	}
497 
498 	size = recv_data(chip, buf, TPM_HEADER_SIZE);
499 	if (size < TPM_HEADER_SIZE) {
500 		dev_err(&chip->dev, "Unable to read header\n");
501 		goto out;
502 	}
503 
504 	expected = be32_to_cpu(*(__be32 *)(buf + 2));
505 	if (expected > count) {
506 		size = -EIO;
507 		goto out;
508 	}
509 
510 	size += recv_data(chip, &buf[TPM_HEADER_SIZE],
511 			expected - TPM_HEADER_SIZE);
512 	if (size < expected) {
513 		dev_err(&chip->dev, "Unable to read remainder of result\n");
514 		size = -ETIME;
515 	}
516 
517 out:
518 	st33zp24_cancel(chip);
519 	release_locality(chip);
520 	return size;
521 }
522 
523 /*
524  * st33zp24_req_canceled
525  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h.
526  * @param: status, the TPM status.
527  * @return: Does TPM ready to compute a new command ? true.
528  */
529 static bool st33zp24_req_canceled(struct tpm_chip *chip, u8 status)
530 {
531 	return (status == TPM_STS_COMMAND_READY);
532 }
533 
534 static const struct tpm_class_ops st33zp24_tpm = {
535 	.send = st33zp24_send,
536 	.recv = st33zp24_recv,
537 	.cancel = st33zp24_cancel,
538 	.status = st33zp24_status,
539 	.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
540 	.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
541 	.req_canceled = st33zp24_req_canceled,
542 };
543 
544 /*
545  * st33zp24_probe initialize the TPM device
546  * @param: client, the i2c_client drescription (TPM I2C description).
547  * @param: id, the i2c_device_id struct.
548  * @return: 0 in case of success.
549  *	 -1 in other case.
550  */
551 int st33zp24_probe(void *phy_id, const struct st33zp24_phy_ops *ops,
552 		   struct device *dev, int irq, int io_lpcpd)
553 {
554 	int ret;
555 	u8 intmask = 0;
556 	struct tpm_chip *chip;
557 	struct st33zp24_dev *tpm_dev;
558 
559 	chip = tpmm_chip_alloc(dev, &st33zp24_tpm);
560 	if (IS_ERR(chip))
561 		return PTR_ERR(chip);
562 
563 	tpm_dev = devm_kzalloc(dev, sizeof(struct st33zp24_dev),
564 			       GFP_KERNEL);
565 	if (!tpm_dev)
566 		return -ENOMEM;
567 
568 	TPM_VPRIV(chip) = tpm_dev;
569 	tpm_dev->phy_id = phy_id;
570 	tpm_dev->ops = ops;
571 
572 	chip->vendor.timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
573 	chip->vendor.timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
574 	chip->vendor.timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
575 	chip->vendor.timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
576 
577 	chip->vendor.locality = LOCALITY0;
578 
579 	if (irq) {
580 		/* INTERRUPT Setup */
581 		init_waitqueue_head(&chip->vendor.read_queue);
582 		tpm_dev->intrs = 0;
583 
584 		if (request_locality(chip) != LOCALITY0) {
585 			ret = -ENODEV;
586 			goto _tpm_clean_answer;
587 		}
588 
589 		clear_interruption(tpm_dev);
590 		ret = devm_request_irq(dev, irq, tpm_ioserirq_handler,
591 				IRQF_TRIGGER_HIGH, "TPM SERIRQ management",
592 				chip);
593 		if (ret < 0) {
594 			dev_err(&chip->dev, "TPM SERIRQ signals %d not available\n",
595 				irq);
596 			goto _tpm_clean_answer;
597 		}
598 
599 		intmask |= TPM_INTF_CMD_READY_INT
600 			|  TPM_INTF_STS_VALID_INT
601 			|  TPM_INTF_DATA_AVAIL_INT;
602 
603 		ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_INT_ENABLE,
604 					 &intmask, 1);
605 		if (ret < 0)
606 			goto _tpm_clean_answer;
607 
608 		intmask = TPM_GLOBAL_INT_ENABLE;
609 		ret = tpm_dev->ops->send(tpm_dev->phy_id, (TPM_INT_ENABLE + 3),
610 					 &intmask, 1);
611 		if (ret < 0)
612 			goto _tpm_clean_answer;
613 
614 		chip->vendor.irq = irq;
615 
616 		disable_irq_nosync(chip->vendor.irq);
617 
618 		tpm_gen_interrupt(chip);
619 	}
620 
621 	tpm_get_timeouts(chip);
622 	tpm_do_selftest(chip);
623 
624 	return tpm_chip_register(chip);
625 _tpm_clean_answer:
626 	dev_info(&chip->dev, "TPM initialization fail\n");
627 	return ret;
628 }
629 EXPORT_SYMBOL(st33zp24_probe);
630 
631 /*
632  * st33zp24_remove remove the TPM device
633  * @param: tpm_data, the tpm phy.
634  * @return: 0 in case of success.
635  */
636 int st33zp24_remove(struct tpm_chip *chip)
637 {
638 	tpm_chip_unregister(chip);
639 	return 0;
640 }
641 EXPORT_SYMBOL(st33zp24_remove);
642 
643 #ifdef CONFIG_PM_SLEEP
644 /*
645  * st33zp24_pm_suspend suspend the TPM device
646  * @param: tpm_data, the tpm phy.
647  * @param: mesg, the power management message.
648  * @return: 0 in case of success.
649  */
650 int st33zp24_pm_suspend(struct device *dev)
651 {
652 	struct tpm_chip *chip = dev_get_drvdata(dev);
653 	struct st33zp24_dev *tpm_dev;
654 	int ret = 0;
655 
656 	tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
657 
658 	if (gpio_is_valid(tpm_dev->io_lpcpd))
659 		gpio_set_value(tpm_dev->io_lpcpd, 0);
660 	else
661 		ret = tpm_pm_suspend(dev);
662 
663 	return ret;
664 } /* st33zp24_pm_suspend() */
665 EXPORT_SYMBOL(st33zp24_pm_suspend);
666 
667 /*
668  * st33zp24_pm_resume resume the TPM device
669  * @param: tpm_data, the tpm phy.
670  * @return: 0 in case of success.
671  */
672 int st33zp24_pm_resume(struct device *dev)
673 {
674 	struct tpm_chip *chip = dev_get_drvdata(dev);
675 	struct st33zp24_dev *tpm_dev;
676 	int ret = 0;
677 
678 	tpm_dev = (struct st33zp24_dev *)TPM_VPRIV(chip);
679 
680 	if (gpio_is_valid(tpm_dev->io_lpcpd)) {
681 		gpio_set_value(tpm_dev->io_lpcpd, 1);
682 		ret = wait_for_stat(chip,
683 				TPM_STS_VALID, chip->vendor.timeout_b,
684 				&chip->vendor.read_queue, false);
685 	} else {
686 		ret = tpm_pm_resume(dev);
687 		if (!ret)
688 			tpm_do_selftest(chip);
689 	}
690 	return ret;
691 } /* st33zp24_pm_resume() */
692 EXPORT_SYMBOL(st33zp24_pm_resume);
693 #endif
694 
695 MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
696 MODULE_DESCRIPTION("ST33ZP24 TPM 1.2 driver");
697 MODULE_VERSION("1.3.0");
698 MODULE_LICENSE("GPL");
699