xref: /linux/drivers/char/tpm/tpm_i2c_nuvoton.c (revision e0bf6c5ca2d3281f231c5f0c9bf145e9513644de)
1 /******************************************************************************
2  * Nuvoton TPM I2C Device Driver Interface for WPCT301/NPCT501,
3  * based on the TCG TPM Interface Spec version 1.2.
4  * Specifications at www.trustedcomputinggroup.org
5  *
6  * Copyright (C) 2011, Nuvoton Technology Corporation.
7  *  Dan Morav <dan.morav@nuvoton.com>
8  * Copyright (C) 2013, Obsidian Research Corp.
9  *  Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
10  *
11  * This program is free software: you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation, either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program.  If not, see http://www.gnu.org/licenses/>.
23  *
24  * Nuvoton contact information: APC.Support@nuvoton.com
25  *****************************************************************************/
26 
27 #include <linux/init.h>
28 #include <linux/module.h>
29 #include <linux/moduleparam.h>
30 #include <linux/slab.h>
31 #include <linux/interrupt.h>
32 #include <linux/wait.h>
33 #include <linux/i2c.h>
34 #include "tpm.h"
35 
36 /* I2C interface offsets */
37 #define TPM_STS                0x00
38 #define TPM_BURST_COUNT        0x01
39 #define TPM_DATA_FIFO_W        0x20
40 #define TPM_DATA_FIFO_R        0x40
41 #define TPM_VID_DID_RID        0x60
42 /* TPM command header size */
43 #define TPM_HEADER_SIZE        10
44 #define TPM_RETRY      5
45 /*
46  * I2C bus device maximum buffer size w/o counting I2C address or command
47  * i.e. max size required for I2C write is 34 = addr, command, 32 bytes data
48  */
49 #define TPM_I2C_MAX_BUF_SIZE           32
50 #define TPM_I2C_RETRY_COUNT            32
51 #define TPM_I2C_BUS_DELAY              1       /* msec */
52 #define TPM_I2C_RETRY_DELAY_SHORT      2       /* msec */
53 #define TPM_I2C_RETRY_DELAY_LONG       10      /* msec */
54 
55 #define I2C_DRIVER_NAME "tpm_i2c_nuvoton"
56 
57 struct priv_data {
58 	unsigned int intrs;
59 };
60 
61 static s32 i2c_nuvoton_read_buf(struct i2c_client *client, u8 offset, u8 size,
62 				u8 *data)
63 {
64 	s32 status;
65 
66 	status = i2c_smbus_read_i2c_block_data(client, offset, size, data);
67 	dev_dbg(&client->dev,
68 		"%s(offset=%u size=%u data=%*ph) -> sts=%d\n", __func__,
69 		offset, size, (int)size, data, status);
70 	return status;
71 }
72 
73 static s32 i2c_nuvoton_write_buf(struct i2c_client *client, u8 offset, u8 size,
74 				 u8 *data)
75 {
76 	s32 status;
77 
78 	status = i2c_smbus_write_i2c_block_data(client, offset, size, data);
79 	dev_dbg(&client->dev,
80 		"%s(offset=%u size=%u data=%*ph) -> sts=%d\n", __func__,
81 		offset, size, (int)size, data, status);
82 	return status;
83 }
84 
85 #define TPM_STS_VALID          0x80
86 #define TPM_STS_COMMAND_READY  0x40
87 #define TPM_STS_GO             0x20
88 #define TPM_STS_DATA_AVAIL     0x10
89 #define TPM_STS_EXPECT         0x08
90 #define TPM_STS_RESPONSE_RETRY 0x02
91 #define TPM_STS_ERR_VAL        0x07    /* bit2...bit0 reads always 0 */
92 
93 #define TPM_I2C_SHORT_TIMEOUT  750     /* ms */
94 #define TPM_I2C_LONG_TIMEOUT   2000    /* 2 sec */
95 
96 /* read TPM_STS register */
97 static u8 i2c_nuvoton_read_status(struct tpm_chip *chip)
98 {
99 	struct i2c_client *client = to_i2c_client(chip->pdev);
100 	s32 status;
101 	u8 data;
102 
103 	status = i2c_nuvoton_read_buf(client, TPM_STS, 1, &data);
104 	if (status <= 0) {
105 		dev_err(chip->pdev, "%s() error return %d\n", __func__,
106 			status);
107 		data = TPM_STS_ERR_VAL;
108 	}
109 
110 	return data;
111 }
112 
113 /* write byte to TPM_STS register */
114 static s32 i2c_nuvoton_write_status(struct i2c_client *client, u8 data)
115 {
116 	s32 status;
117 	int i;
118 
119 	/* this causes the current command to be aborted */
120 	for (i = 0, status = -1; i < TPM_I2C_RETRY_COUNT && status < 0; i++) {
121 		status = i2c_nuvoton_write_buf(client, TPM_STS, 1, &data);
122 		msleep(TPM_I2C_BUS_DELAY);
123 	}
124 	return status;
125 }
126 
127 /* write commandReady to TPM_STS register */
128 static void i2c_nuvoton_ready(struct tpm_chip *chip)
129 {
130 	struct i2c_client *client = to_i2c_client(chip->pdev);
131 	s32 status;
132 
133 	/* this causes the current command to be aborted */
134 	status = i2c_nuvoton_write_status(client, TPM_STS_COMMAND_READY);
135 	if (status < 0)
136 		dev_err(chip->pdev,
137 			"%s() fail to write TPM_STS.commandReady\n", __func__);
138 }
139 
140 /* read burstCount field from TPM_STS register
141  * return -1 on fail to read */
142 static int i2c_nuvoton_get_burstcount(struct i2c_client *client,
143 				      struct tpm_chip *chip)
144 {
145 	unsigned long stop = jiffies + chip->vendor.timeout_d;
146 	s32 status;
147 	int burst_count = -1;
148 	u8 data;
149 
150 	/* wait for burstcount to be non-zero */
151 	do {
152 		/* in I2C burstCount is 1 byte */
153 		status = i2c_nuvoton_read_buf(client, TPM_BURST_COUNT, 1,
154 					      &data);
155 		if (status > 0 && data > 0) {
156 			burst_count = min_t(u8, TPM_I2C_MAX_BUF_SIZE, data);
157 			break;
158 		}
159 		msleep(TPM_I2C_BUS_DELAY);
160 	} while (time_before(jiffies, stop));
161 
162 	return burst_count;
163 }
164 
165 /*
166  * WPCT301/NPCT501 SINT# supports only dataAvail
167  * any call to this function which is not waiting for dataAvail will
168  * set queue to NULL to avoid waiting for interrupt
169  */
170 static bool i2c_nuvoton_check_status(struct tpm_chip *chip, u8 mask, u8 value)
171 {
172 	u8 status = i2c_nuvoton_read_status(chip);
173 	return (status != TPM_STS_ERR_VAL) && ((status & mask) == value);
174 }
175 
176 static int i2c_nuvoton_wait_for_stat(struct tpm_chip *chip, u8 mask, u8 value,
177 				     u32 timeout, wait_queue_head_t *queue)
178 {
179 	if (chip->vendor.irq && queue) {
180 		s32 rc;
181 		struct priv_data *priv = chip->vendor.priv;
182 		unsigned int cur_intrs = priv->intrs;
183 
184 		enable_irq(chip->vendor.irq);
185 		rc = wait_event_interruptible_timeout(*queue,
186 						      cur_intrs != priv->intrs,
187 						      timeout);
188 		if (rc > 0)
189 			return 0;
190 		/* At this point we know that the SINT pin is asserted, so we
191 		 * do not need to do i2c_nuvoton_check_status */
192 	} else {
193 		unsigned long ten_msec, stop;
194 		bool status_valid;
195 
196 		/* check current status */
197 		status_valid = i2c_nuvoton_check_status(chip, mask, value);
198 		if (status_valid)
199 			return 0;
200 
201 		/* use polling to wait for the event */
202 		ten_msec = jiffies + msecs_to_jiffies(TPM_I2C_RETRY_DELAY_LONG);
203 		stop = jiffies + timeout;
204 		do {
205 			if (time_before(jiffies, ten_msec))
206 				msleep(TPM_I2C_RETRY_DELAY_SHORT);
207 			else
208 				msleep(TPM_I2C_RETRY_DELAY_LONG);
209 			status_valid = i2c_nuvoton_check_status(chip, mask,
210 								value);
211 			if (status_valid)
212 				return 0;
213 		} while (time_before(jiffies, stop));
214 	}
215 	dev_err(chip->pdev, "%s(%02x, %02x) -> timeout\n", __func__, mask,
216 		value);
217 	return -ETIMEDOUT;
218 }
219 
220 /* wait for dataAvail field to be set in the TPM_STS register */
221 static int i2c_nuvoton_wait_for_data_avail(struct tpm_chip *chip, u32 timeout,
222 					   wait_queue_head_t *queue)
223 {
224 	return i2c_nuvoton_wait_for_stat(chip,
225 					 TPM_STS_DATA_AVAIL | TPM_STS_VALID,
226 					 TPM_STS_DATA_AVAIL | TPM_STS_VALID,
227 					 timeout, queue);
228 }
229 
230 /* Read @count bytes into @buf from TPM_RD_FIFO register */
231 static int i2c_nuvoton_recv_data(struct i2c_client *client,
232 				 struct tpm_chip *chip, u8 *buf, size_t count)
233 {
234 	s32 rc;
235 	int burst_count, bytes2read, size = 0;
236 
237 	while (size < count &&
238 	       i2c_nuvoton_wait_for_data_avail(chip,
239 					       chip->vendor.timeout_c,
240 					       &chip->vendor.read_queue) == 0) {
241 		burst_count = i2c_nuvoton_get_burstcount(client, chip);
242 		if (burst_count < 0) {
243 			dev_err(chip->pdev,
244 				"%s() fail to read burstCount=%d\n", __func__,
245 				burst_count);
246 			return -EIO;
247 		}
248 		bytes2read = min_t(size_t, burst_count, count - size);
249 		rc = i2c_nuvoton_read_buf(client, TPM_DATA_FIFO_R,
250 					  bytes2read, &buf[size]);
251 		if (rc < 0) {
252 			dev_err(chip->pdev,
253 				"%s() fail on i2c_nuvoton_read_buf()=%d\n",
254 				__func__, rc);
255 			return -EIO;
256 		}
257 		dev_dbg(chip->pdev, "%s(%d):", __func__, bytes2read);
258 		size += bytes2read;
259 	}
260 
261 	return size;
262 }
263 
264 /* Read TPM command results */
265 static int i2c_nuvoton_recv(struct tpm_chip *chip, u8 *buf, size_t count)
266 {
267 	struct device *dev = chip->pdev;
268 	struct i2c_client *client = to_i2c_client(dev);
269 	s32 rc;
270 	int expected, status, burst_count, retries, size = 0;
271 
272 	if (count < TPM_HEADER_SIZE) {
273 		i2c_nuvoton_ready(chip);    /* return to idle */
274 		dev_err(dev, "%s() count < header size\n", __func__);
275 		return -EIO;
276 	}
277 	for (retries = 0; retries < TPM_RETRY; retries++) {
278 		if (retries > 0) {
279 			/* if this is not the first trial, set responseRetry */
280 			i2c_nuvoton_write_status(client,
281 						 TPM_STS_RESPONSE_RETRY);
282 		}
283 		/*
284 		 * read first available (> 10 bytes), including:
285 		 * tag, paramsize, and result
286 		 */
287 		status = i2c_nuvoton_wait_for_data_avail(
288 			chip, chip->vendor.timeout_c, &chip->vendor.read_queue);
289 		if (status != 0) {
290 			dev_err(dev, "%s() timeout on dataAvail\n", __func__);
291 			size = -ETIMEDOUT;
292 			continue;
293 		}
294 		burst_count = i2c_nuvoton_get_burstcount(client, chip);
295 		if (burst_count < 0) {
296 			dev_err(dev, "%s() fail to get burstCount\n", __func__);
297 			size = -EIO;
298 			continue;
299 		}
300 		size = i2c_nuvoton_recv_data(client, chip, buf,
301 					     burst_count);
302 		if (size < TPM_HEADER_SIZE) {
303 			dev_err(dev, "%s() fail to read header\n", __func__);
304 			size = -EIO;
305 			continue;
306 		}
307 		/*
308 		 * convert number of expected bytes field from big endian 32 bit
309 		 * to machine native
310 		 */
311 		expected = be32_to_cpu(*(__be32 *) (buf + 2));
312 		if (expected > count) {
313 			dev_err(dev, "%s() expected > count\n", __func__);
314 			size = -EIO;
315 			continue;
316 		}
317 		rc = i2c_nuvoton_recv_data(client, chip, &buf[size],
318 					   expected - size);
319 		size += rc;
320 		if (rc < 0 || size < expected) {
321 			dev_err(dev, "%s() fail to read remainder of result\n",
322 				__func__);
323 			size = -EIO;
324 			continue;
325 		}
326 		if (i2c_nuvoton_wait_for_stat(
327 			    chip, TPM_STS_VALID | TPM_STS_DATA_AVAIL,
328 			    TPM_STS_VALID, chip->vendor.timeout_c,
329 			    NULL)) {
330 			dev_err(dev, "%s() error left over data\n", __func__);
331 			size = -ETIMEDOUT;
332 			continue;
333 		}
334 		break;
335 	}
336 	i2c_nuvoton_ready(chip);
337 	dev_dbg(chip->pdev, "%s() -> %d\n", __func__, size);
338 	return size;
339 }
340 
341 /*
342  * Send TPM command.
343  *
344  * If interrupts are used (signaled by an irq set in the vendor structure)
345  * tpm.c can skip polling for the data to be available as the interrupt is
346  * waited for here
347  */
348 static int i2c_nuvoton_send(struct tpm_chip *chip, u8 *buf, size_t len)
349 {
350 	struct device *dev = chip->pdev;
351 	struct i2c_client *client = to_i2c_client(dev);
352 	u32 ordinal;
353 	size_t count = 0;
354 	int burst_count, bytes2write, retries, rc = -EIO;
355 
356 	for (retries = 0; retries < TPM_RETRY; retries++) {
357 		i2c_nuvoton_ready(chip);
358 		if (i2c_nuvoton_wait_for_stat(chip, TPM_STS_COMMAND_READY,
359 					      TPM_STS_COMMAND_READY,
360 					      chip->vendor.timeout_b, NULL)) {
361 			dev_err(dev, "%s() timeout on commandReady\n",
362 				__func__);
363 			rc = -EIO;
364 			continue;
365 		}
366 		rc = 0;
367 		while (count < len - 1) {
368 			burst_count = i2c_nuvoton_get_burstcount(client,
369 								 chip);
370 			if (burst_count < 0) {
371 				dev_err(dev, "%s() fail get burstCount\n",
372 					__func__);
373 				rc = -EIO;
374 				break;
375 			}
376 			bytes2write = min_t(size_t, burst_count,
377 					    len - 1 - count);
378 			rc = i2c_nuvoton_write_buf(client, TPM_DATA_FIFO_W,
379 						   bytes2write, &buf[count]);
380 			if (rc < 0) {
381 				dev_err(dev, "%s() fail i2cWriteBuf\n",
382 					__func__);
383 				break;
384 			}
385 			dev_dbg(dev, "%s(%d):", __func__, bytes2write);
386 			count += bytes2write;
387 			rc = i2c_nuvoton_wait_for_stat(chip,
388 						       TPM_STS_VALID |
389 						       TPM_STS_EXPECT,
390 						       TPM_STS_VALID |
391 						       TPM_STS_EXPECT,
392 						       chip->vendor.timeout_c,
393 						       NULL);
394 			if (rc < 0) {
395 				dev_err(dev, "%s() timeout on Expect\n",
396 					__func__);
397 				rc = -ETIMEDOUT;
398 				break;
399 			}
400 		}
401 		if (rc < 0)
402 			continue;
403 
404 		/* write last byte */
405 		rc = i2c_nuvoton_write_buf(client, TPM_DATA_FIFO_W, 1,
406 					   &buf[count]);
407 		if (rc < 0) {
408 			dev_err(dev, "%s() fail to write last byte\n",
409 				__func__);
410 			rc = -EIO;
411 			continue;
412 		}
413 		dev_dbg(dev, "%s(last): %02x", __func__, buf[count]);
414 		rc = i2c_nuvoton_wait_for_stat(chip,
415 					       TPM_STS_VALID | TPM_STS_EXPECT,
416 					       TPM_STS_VALID,
417 					       chip->vendor.timeout_c, NULL);
418 		if (rc) {
419 			dev_err(dev, "%s() timeout on Expect to clear\n",
420 				__func__);
421 			rc = -ETIMEDOUT;
422 			continue;
423 		}
424 		break;
425 	}
426 	if (rc < 0) {
427 		/* retries == TPM_RETRY */
428 		i2c_nuvoton_ready(chip);
429 		return rc;
430 	}
431 	/* execute the TPM command */
432 	rc = i2c_nuvoton_write_status(client, TPM_STS_GO);
433 	if (rc < 0) {
434 		dev_err(dev, "%s() fail to write Go\n", __func__);
435 		i2c_nuvoton_ready(chip);
436 		return rc;
437 	}
438 	ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
439 	rc = i2c_nuvoton_wait_for_data_avail(chip,
440 					     tpm_calc_ordinal_duration(chip,
441 								       ordinal),
442 					     &chip->vendor.read_queue);
443 	if (rc) {
444 		dev_err(dev, "%s() timeout command duration\n", __func__);
445 		i2c_nuvoton_ready(chip);
446 		return rc;
447 	}
448 
449 	dev_dbg(dev, "%s() -> %zd\n", __func__, len);
450 	return len;
451 }
452 
453 static bool i2c_nuvoton_req_canceled(struct tpm_chip *chip, u8 status)
454 {
455 	return (status == TPM_STS_COMMAND_READY);
456 }
457 
458 static const struct tpm_class_ops tpm_i2c = {
459 	.status = i2c_nuvoton_read_status,
460 	.recv = i2c_nuvoton_recv,
461 	.send = i2c_nuvoton_send,
462 	.cancel = i2c_nuvoton_ready,
463 	.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
464 	.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
465 	.req_canceled = i2c_nuvoton_req_canceled,
466 };
467 
468 /* The only purpose for the handler is to signal to any waiting threads that
469  * the interrupt is currently being asserted. The driver does not do any
470  * processing triggered by interrupts, and the chip provides no way to mask at
471  * the source (plus that would be slow over I2C). Run the IRQ as a one-shot,
472  * this means it cannot be shared. */
473 static irqreturn_t i2c_nuvoton_int_handler(int dummy, void *dev_id)
474 {
475 	struct tpm_chip *chip = dev_id;
476 	struct priv_data *priv = chip->vendor.priv;
477 
478 	priv->intrs++;
479 	wake_up(&chip->vendor.read_queue);
480 	disable_irq_nosync(chip->vendor.irq);
481 	return IRQ_HANDLED;
482 }
483 
484 static int get_vid(struct i2c_client *client, u32 *res)
485 {
486 	static const u8 vid_did_rid_value[] = { 0x50, 0x10, 0xfe };
487 	u32 temp;
488 	s32 rc;
489 
490 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
491 		return -ENODEV;
492 	rc = i2c_nuvoton_read_buf(client, TPM_VID_DID_RID, 4, (u8 *)&temp);
493 	if (rc < 0)
494 		return rc;
495 
496 	/* check WPCT301 values - ignore RID */
497 	if (memcmp(&temp, vid_did_rid_value, sizeof(vid_did_rid_value))) {
498 		/*
499 		 * f/w rev 2.81 has an issue where the VID_DID_RID is not
500 		 * reporting the right value. so give it another chance at
501 		 * offset 0x20 (FIFO_W).
502 		 */
503 		rc = i2c_nuvoton_read_buf(client, TPM_DATA_FIFO_W, 4,
504 					  (u8 *) (&temp));
505 		if (rc < 0)
506 			return rc;
507 
508 		/* check WPCT301 values - ignore RID */
509 		if (memcmp(&temp, vid_did_rid_value,
510 			   sizeof(vid_did_rid_value)))
511 			return -ENODEV;
512 	}
513 
514 	*res = temp;
515 	return 0;
516 }
517 
518 static int i2c_nuvoton_probe(struct i2c_client *client,
519 			     const struct i2c_device_id *id)
520 {
521 	int rc;
522 	struct tpm_chip *chip;
523 	struct device *dev = &client->dev;
524 	u32 vid = 0;
525 
526 	rc = get_vid(client, &vid);
527 	if (rc)
528 		return rc;
529 
530 	dev_info(dev, "VID: %04X DID: %02X RID: %02X\n", (u16) vid,
531 		 (u8) (vid >> 16), (u8) (vid >> 24));
532 
533 	chip = tpmm_chip_alloc(dev, &tpm_i2c);
534 	if (IS_ERR(chip))
535 		return PTR_ERR(chip);
536 
537 	chip->vendor.priv = devm_kzalloc(dev, sizeof(struct priv_data),
538 					 GFP_KERNEL);
539 	if (!chip->vendor.priv)
540 		return -ENOMEM;
541 
542 	init_waitqueue_head(&chip->vendor.read_queue);
543 	init_waitqueue_head(&chip->vendor.int_queue);
544 
545 	/* Default timeouts */
546 	chip->vendor.timeout_a = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
547 	chip->vendor.timeout_b = msecs_to_jiffies(TPM_I2C_LONG_TIMEOUT);
548 	chip->vendor.timeout_c = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
549 	chip->vendor.timeout_d = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
550 
551 	/*
552 	 * I2C intfcaps (interrupt capabilitieis) in the chip are hard coded to:
553 	 *   TPM_INTF_INT_LEVEL_LOW | TPM_INTF_DATA_AVAIL_INT
554 	 * The IRQ should be set in the i2c_board_info (which is done
555 	 * automatically in of_i2c_register_devices, for device tree users */
556 	chip->vendor.irq = client->irq;
557 
558 	if (chip->vendor.irq) {
559 		dev_dbg(dev, "%s() chip-vendor.irq\n", __func__);
560 		rc = devm_request_irq(dev, chip->vendor.irq,
561 				      i2c_nuvoton_int_handler,
562 				      IRQF_TRIGGER_LOW,
563 				      chip->devname,
564 				      chip);
565 		if (rc) {
566 			dev_err(dev, "%s() Unable to request irq: %d for use\n",
567 				__func__, chip->vendor.irq);
568 			chip->vendor.irq = 0;
569 		} else {
570 			/* Clear any pending interrupt */
571 			i2c_nuvoton_ready(chip);
572 			/* - wait for TPM_STS==0xA0 (stsValid, commandReady) */
573 			rc = i2c_nuvoton_wait_for_stat(chip,
574 						       TPM_STS_COMMAND_READY,
575 						       TPM_STS_COMMAND_READY,
576 						       chip->vendor.timeout_b,
577 						       NULL);
578 			if (rc == 0) {
579 				/*
580 				 * TIS is in ready state
581 				 * write dummy byte to enter reception state
582 				 * TPM_DATA_FIFO_W <- rc (0)
583 				 */
584 				rc = i2c_nuvoton_write_buf(client,
585 							   TPM_DATA_FIFO_W,
586 							   1, (u8 *) (&rc));
587 				if (rc < 0)
588 					return rc;
589 				/* TPM_STS <- 0x40 (commandReady) */
590 				i2c_nuvoton_ready(chip);
591 			} else {
592 				/*
593 				 * timeout_b reached - command was
594 				 * aborted. TIS should now be in idle state -
595 				 * only TPM_STS_VALID should be set
596 				 */
597 				if (i2c_nuvoton_read_status(chip) !=
598 				    TPM_STS_VALID)
599 					return -EIO;
600 			}
601 		}
602 	}
603 
604 	if (tpm_get_timeouts(chip))
605 		return -ENODEV;
606 
607 	if (tpm_do_selftest(chip))
608 		return -ENODEV;
609 
610 	return tpm_chip_register(chip);
611 }
612 
613 static int i2c_nuvoton_remove(struct i2c_client *client)
614 {
615 	struct device *dev = &(client->dev);
616 	struct tpm_chip *chip = dev_get_drvdata(dev);
617 	tpm_chip_unregister(chip);
618 	return 0;
619 }
620 
621 static const struct i2c_device_id i2c_nuvoton_id[] = {
622 	{I2C_DRIVER_NAME, 0},
623 	{}
624 };
625 MODULE_DEVICE_TABLE(i2c, i2c_nuvoton_id);
626 
627 #ifdef CONFIG_OF
628 static const struct of_device_id i2c_nuvoton_of_match[] = {
629 	{.compatible = "nuvoton,npct501"},
630 	{.compatible = "winbond,wpct301"},
631 	{},
632 };
633 MODULE_DEVICE_TABLE(of, i2c_nuvoton_of_match);
634 #endif
635 
636 static SIMPLE_DEV_PM_OPS(i2c_nuvoton_pm_ops, tpm_pm_suspend, tpm_pm_resume);
637 
638 static struct i2c_driver i2c_nuvoton_driver = {
639 	.id_table = i2c_nuvoton_id,
640 	.probe = i2c_nuvoton_probe,
641 	.remove = i2c_nuvoton_remove,
642 	.driver = {
643 		.name = I2C_DRIVER_NAME,
644 		.owner = THIS_MODULE,
645 		.pm = &i2c_nuvoton_pm_ops,
646 		.of_match_table = of_match_ptr(i2c_nuvoton_of_match),
647 	},
648 };
649 
650 module_i2c_driver(i2c_nuvoton_driver);
651 
652 MODULE_AUTHOR("Dan Morav (dan.morav@nuvoton.com)");
653 MODULE_DESCRIPTION("Nuvoton TPM I2C Driver");
654 MODULE_LICENSE("GPL");
655