xref: /linux/drivers/char/tpm/tpm_i2c_nuvoton.c (revision 71dfa617ea9f18e4585fe78364217cd32b1fc382)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2  /******************************************************************************
3  * Nuvoton TPM I2C Device Driver Interface for WPCT301/NPCT501/NPCT6XX,
4  * based on the TCG TPM Interface Spec version 1.2.
5  * Specifications at www.trustedcomputinggroup.org
6  *
7  * Copyright (C) 2011, Nuvoton Technology Corporation.
8  *  Dan Morav <dan.morav@nuvoton.com>
9  * Copyright (C) 2013, Obsidian Research Corp.
10  *  Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
11  *
12  * Nuvoton contact information: APC.Support@nuvoton.com
13  *****************************************************************************/
14 
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/slab.h>
19 #include <linux/interrupt.h>
20 #include <linux/wait.h>
21 #include <linux/i2c.h>
22 #include <linux/of.h>
23 #include <linux/property.h>
24 #include "tpm.h"
25 
26 /* I2C interface offsets */
27 #define TPM_STS			0x00
28 #define TPM_BURST_COUNT		0x01
29 #define TPM_DATA_FIFO_W		0x20
30 #define TPM_DATA_FIFO_R		0x40
31 #define TPM_VID_DID_RID		0x60
32 #define TPM_I2C_RETRIES		5
33 /*
34  * I2C bus device maximum buffer size w/o counting I2C address or command
35  * i.e. max size required for I2C write is 34 = addr, command, 32 bytes data
36  */
37 #define TPM_I2C_MAX_BUF_SIZE           32
38 #define TPM_I2C_RETRY_COUNT            32
39 #define TPM_I2C_BUS_DELAY              1000      	/* usec */
40 #define TPM_I2C_RETRY_DELAY_SHORT      (2 * 1000)	/* usec */
41 #define TPM_I2C_RETRY_DELAY_LONG       (10 * 1000) 	/* usec */
42 #define TPM_I2C_DELAY_RANGE            300		/* usec */
43 
44 #define OF_IS_TPM2 ((void *)1)
45 #define I2C_IS_TPM2 1
46 
47 struct priv_data {
48 	int irq;
49 	unsigned int intrs;
50 	wait_queue_head_t read_queue;
51 };
52 
53 static s32 i2c_nuvoton_read_buf(struct i2c_client *client, u8 offset, u8 size,
54 				u8 *data)
55 {
56 	s32 status;
57 
58 	status = i2c_smbus_read_i2c_block_data(client, offset, size, data);
59 	dev_dbg(&client->dev,
60 		"%s(offset=%u size=%u data=%*ph) -> sts=%d\n", __func__,
61 		offset, size, (int)size, data, status);
62 	return status;
63 }
64 
65 static s32 i2c_nuvoton_write_buf(struct i2c_client *client, u8 offset, u8 size,
66 				 u8 *data)
67 {
68 	s32 status;
69 
70 	status = i2c_smbus_write_i2c_block_data(client, offset, size, data);
71 	dev_dbg(&client->dev,
72 		"%s(offset=%u size=%u data=%*ph) -> sts=%d\n", __func__,
73 		offset, size, (int)size, data, status);
74 	return status;
75 }
76 
77 #define TPM_STS_VALID          0x80
78 #define TPM_STS_COMMAND_READY  0x40
79 #define TPM_STS_GO             0x20
80 #define TPM_STS_DATA_AVAIL     0x10
81 #define TPM_STS_EXPECT         0x08
82 #define TPM_STS_RESPONSE_RETRY 0x02
83 #define TPM_STS_ERR_VAL        0x07    /* bit2...bit0 reads always 0 */
84 
85 #define TPM_I2C_SHORT_TIMEOUT  750     /* ms */
86 #define TPM_I2C_LONG_TIMEOUT   2000    /* 2 sec */
87 
88 /* read TPM_STS register */
89 static u8 i2c_nuvoton_read_status(struct tpm_chip *chip)
90 {
91 	struct i2c_client *client = to_i2c_client(chip->dev.parent);
92 	s32 status;
93 	u8 data;
94 
95 	status = i2c_nuvoton_read_buf(client, TPM_STS, 1, &data);
96 	if (status <= 0) {
97 		dev_err(&chip->dev, "%s() error return %d\n", __func__,
98 			status);
99 		data = TPM_STS_ERR_VAL;
100 	}
101 
102 	return data;
103 }
104 
105 /* write byte to TPM_STS register */
106 static s32 i2c_nuvoton_write_status(struct i2c_client *client, u8 data)
107 {
108 	s32 status;
109 	int i;
110 
111 	/* this causes the current command to be aborted */
112 	for (i = 0, status = -1; i < TPM_I2C_RETRY_COUNT && status < 0; i++) {
113 		status = i2c_nuvoton_write_buf(client, TPM_STS, 1, &data);
114 		if (status < 0)
115 			usleep_range(TPM_I2C_BUS_DELAY, TPM_I2C_BUS_DELAY
116 				     + TPM_I2C_DELAY_RANGE);
117 	}
118 	return status;
119 }
120 
121 /* write commandReady to TPM_STS register */
122 static void i2c_nuvoton_ready(struct tpm_chip *chip)
123 {
124 	struct i2c_client *client = to_i2c_client(chip->dev.parent);
125 	s32 status;
126 
127 	/* this causes the current command to be aborted */
128 	status = i2c_nuvoton_write_status(client, TPM_STS_COMMAND_READY);
129 	if (status < 0)
130 		dev_err(&chip->dev,
131 			"%s() fail to write TPM_STS.commandReady\n", __func__);
132 }
133 
134 /* read burstCount field from TPM_STS register
135  * return -1 on fail to read */
136 static int i2c_nuvoton_get_burstcount(struct i2c_client *client,
137 				      struct tpm_chip *chip)
138 {
139 	unsigned long stop = jiffies + chip->timeout_d;
140 	s32 status;
141 	int burst_count = -1;
142 	u8 data;
143 
144 	/* wait for burstcount to be non-zero */
145 	do {
146 		/* in I2C burstCount is 1 byte */
147 		status = i2c_nuvoton_read_buf(client, TPM_BURST_COUNT, 1,
148 					      &data);
149 		if (status > 0 && data > 0) {
150 			burst_count = min_t(u8, TPM_I2C_MAX_BUF_SIZE, data);
151 			break;
152 		}
153 		usleep_range(TPM_I2C_BUS_DELAY, TPM_I2C_BUS_DELAY
154 			     + TPM_I2C_DELAY_RANGE);
155 	} while (time_before(jiffies, stop));
156 
157 	return burst_count;
158 }
159 
160 /*
161  * WPCT301/NPCT501/NPCT6XX SINT# supports only dataAvail
162  * any call to this function which is not waiting for dataAvail will
163  * set queue to NULL to avoid waiting for interrupt
164  */
165 static bool i2c_nuvoton_check_status(struct tpm_chip *chip, u8 mask, u8 value)
166 {
167 	u8 status = i2c_nuvoton_read_status(chip);
168 	return (status != TPM_STS_ERR_VAL) && ((status & mask) == value);
169 }
170 
171 static int i2c_nuvoton_wait_for_stat(struct tpm_chip *chip, u8 mask, u8 value,
172 				     u32 timeout, wait_queue_head_t *queue)
173 {
174 	if ((chip->flags & TPM_CHIP_FLAG_IRQ) && queue) {
175 		s32 rc;
176 		struct priv_data *priv = dev_get_drvdata(&chip->dev);
177 		unsigned int cur_intrs = priv->intrs;
178 
179 		enable_irq(priv->irq);
180 		rc = wait_event_interruptible_timeout(*queue,
181 						      cur_intrs != priv->intrs,
182 						      timeout);
183 		if (rc > 0)
184 			return 0;
185 		/* At this point we know that the SINT pin is asserted, so we
186 		 * do not need to do i2c_nuvoton_check_status */
187 	} else {
188 		unsigned long ten_msec, stop;
189 		bool status_valid;
190 
191 		/* check current status */
192 		status_valid = i2c_nuvoton_check_status(chip, mask, value);
193 		if (status_valid)
194 			return 0;
195 
196 		/* use polling to wait for the event */
197 		ten_msec = jiffies + usecs_to_jiffies(TPM_I2C_RETRY_DELAY_LONG);
198 		stop = jiffies + timeout;
199 		do {
200 			if (time_before(jiffies, ten_msec))
201 				usleep_range(TPM_I2C_RETRY_DELAY_SHORT,
202 					     TPM_I2C_RETRY_DELAY_SHORT
203 					     + TPM_I2C_DELAY_RANGE);
204 			else
205 				usleep_range(TPM_I2C_RETRY_DELAY_LONG,
206 					     TPM_I2C_RETRY_DELAY_LONG
207 					     + TPM_I2C_DELAY_RANGE);
208 			status_valid = i2c_nuvoton_check_status(chip, mask,
209 								value);
210 			if (status_valid)
211 				return 0;
212 		} while (time_before(jiffies, stop));
213 	}
214 	dev_err(&chip->dev, "%s(%02x, %02x) -> timeout\n", __func__, mask,
215 		value);
216 	return -ETIMEDOUT;
217 }
218 
219 /* wait for dataAvail field to be set in the TPM_STS register */
220 static int i2c_nuvoton_wait_for_data_avail(struct tpm_chip *chip, u32 timeout,
221 					   wait_queue_head_t *queue)
222 {
223 	return i2c_nuvoton_wait_for_stat(chip,
224 					 TPM_STS_DATA_AVAIL | TPM_STS_VALID,
225 					 TPM_STS_DATA_AVAIL | TPM_STS_VALID,
226 					 timeout, queue);
227 }
228 
229 /* Read @count bytes into @buf from TPM_RD_FIFO register */
230 static int i2c_nuvoton_recv_data(struct i2c_client *client,
231 				 struct tpm_chip *chip, u8 *buf, size_t count)
232 {
233 	struct priv_data *priv = dev_get_drvdata(&chip->dev);
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->timeout_c,
240 					       &priv->read_queue) == 0) {
241 		burst_count = i2c_nuvoton_get_burstcount(client, chip);
242 		if (burst_count < 0) {
243 			dev_err(&chip->dev,
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->dev,
253 				"%s() fail on i2c_nuvoton_read_buf()=%d\n",
254 				__func__, rc);
255 			return -EIO;
256 		}
257 		dev_dbg(&chip->dev, "%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 priv_data *priv = dev_get_drvdata(&chip->dev);
268 	struct device *dev = chip->dev.parent;
269 	struct i2c_client *client = to_i2c_client(dev);
270 	s32 rc;
271 	int status;
272 	int burst_count;
273 	int retries;
274 	int size = 0;
275 	u32 expected;
276 
277 	if (count < TPM_HEADER_SIZE) {
278 		i2c_nuvoton_ready(chip);    /* return to idle */
279 		dev_err(dev, "%s() count < header size\n", __func__);
280 		return -EIO;
281 	}
282 	for (retries = 0; retries < TPM_I2C_RETRIES; retries++) {
283 		if (retries > 0) {
284 			/* if this is not the first trial, set responseRetry */
285 			i2c_nuvoton_write_status(client,
286 						 TPM_STS_RESPONSE_RETRY);
287 		}
288 		/*
289 		 * read first available (> 10 bytes), including:
290 		 * tag, paramsize, and result
291 		 */
292 		status = i2c_nuvoton_wait_for_data_avail(
293 			chip, chip->timeout_c, &priv->read_queue);
294 		if (status != 0) {
295 			dev_err(dev, "%s() timeout on dataAvail\n", __func__);
296 			size = -ETIMEDOUT;
297 			continue;
298 		}
299 		burst_count = i2c_nuvoton_get_burstcount(client, chip);
300 		if (burst_count < 0) {
301 			dev_err(dev, "%s() fail to get burstCount\n", __func__);
302 			size = -EIO;
303 			continue;
304 		}
305 		size = i2c_nuvoton_recv_data(client, chip, buf,
306 					     burst_count);
307 		if (size < TPM_HEADER_SIZE) {
308 			dev_err(dev, "%s() fail to read header\n", __func__);
309 			size = -EIO;
310 			continue;
311 		}
312 		/*
313 		 * convert number of expected bytes field from big endian 32 bit
314 		 * to machine native
315 		 */
316 		expected = be32_to_cpu(*(__be32 *) (buf + 2));
317 		if (expected > count || expected < size) {
318 			dev_err(dev, "%s() expected > count\n", __func__);
319 			size = -EIO;
320 			continue;
321 		}
322 		rc = i2c_nuvoton_recv_data(client, chip, &buf[size],
323 					   expected - size);
324 		size += rc;
325 		if (rc < 0 || size < expected) {
326 			dev_err(dev, "%s() fail to read remainder of result\n",
327 				__func__);
328 			size = -EIO;
329 			continue;
330 		}
331 		if (i2c_nuvoton_wait_for_stat(
332 			    chip, TPM_STS_VALID | TPM_STS_DATA_AVAIL,
333 			    TPM_STS_VALID, chip->timeout_c,
334 			    NULL)) {
335 			dev_err(dev, "%s() error left over data\n", __func__);
336 			size = -ETIMEDOUT;
337 			continue;
338 		}
339 		break;
340 	}
341 	i2c_nuvoton_ready(chip);
342 	dev_dbg(&chip->dev, "%s() -> %d\n", __func__, size);
343 	return size;
344 }
345 
346 /*
347  * Send TPM command.
348  *
349  * If interrupts are used (signaled by an irq set in the vendor structure)
350  * tpm.c can skip polling for the data to be available as the interrupt is
351  * waited for here
352  */
353 static int i2c_nuvoton_send(struct tpm_chip *chip, u8 *buf, size_t len)
354 {
355 	struct priv_data *priv = dev_get_drvdata(&chip->dev);
356 	struct device *dev = chip->dev.parent;
357 	struct i2c_client *client = to_i2c_client(dev);
358 	u32 ordinal;
359 	unsigned long duration;
360 	size_t count = 0;
361 	int burst_count, bytes2write, retries, rc = -EIO;
362 
363 	for (retries = 0; retries < TPM_RETRY; retries++) {
364 		i2c_nuvoton_ready(chip);
365 		if (i2c_nuvoton_wait_for_stat(chip, TPM_STS_COMMAND_READY,
366 					      TPM_STS_COMMAND_READY,
367 					      chip->timeout_b, NULL)) {
368 			dev_err(dev, "%s() timeout on commandReady\n",
369 				__func__);
370 			rc = -EIO;
371 			continue;
372 		}
373 		rc = 0;
374 		while (count < len - 1) {
375 			burst_count = i2c_nuvoton_get_burstcount(client,
376 								 chip);
377 			if (burst_count < 0) {
378 				dev_err(dev, "%s() fail get burstCount\n",
379 					__func__);
380 				rc = -EIO;
381 				break;
382 			}
383 			bytes2write = min_t(size_t, burst_count,
384 					    len - 1 - count);
385 			rc = i2c_nuvoton_write_buf(client, TPM_DATA_FIFO_W,
386 						   bytes2write, &buf[count]);
387 			if (rc < 0) {
388 				dev_err(dev, "%s() fail i2cWriteBuf\n",
389 					__func__);
390 				break;
391 			}
392 			dev_dbg(dev, "%s(%d):", __func__, bytes2write);
393 			count += bytes2write;
394 			rc = i2c_nuvoton_wait_for_stat(chip,
395 						       TPM_STS_VALID |
396 						       TPM_STS_EXPECT,
397 						       TPM_STS_VALID |
398 						       TPM_STS_EXPECT,
399 						       chip->timeout_c,
400 						       NULL);
401 			if (rc < 0) {
402 				dev_err(dev, "%s() timeout on Expect\n",
403 					__func__);
404 				rc = -ETIMEDOUT;
405 				break;
406 			}
407 		}
408 		if (rc < 0)
409 			continue;
410 
411 		/* write last byte */
412 		rc = i2c_nuvoton_write_buf(client, TPM_DATA_FIFO_W, 1,
413 					   &buf[count]);
414 		if (rc < 0) {
415 			dev_err(dev, "%s() fail to write last byte\n",
416 				__func__);
417 			rc = -EIO;
418 			continue;
419 		}
420 		dev_dbg(dev, "%s(last): %02x", __func__, buf[count]);
421 		rc = i2c_nuvoton_wait_for_stat(chip,
422 					       TPM_STS_VALID | TPM_STS_EXPECT,
423 					       TPM_STS_VALID,
424 					       chip->timeout_c, NULL);
425 		if (rc) {
426 			dev_err(dev, "%s() timeout on Expect to clear\n",
427 				__func__);
428 			rc = -ETIMEDOUT;
429 			continue;
430 		}
431 		break;
432 	}
433 	if (rc < 0) {
434 		/* retries == TPM_RETRY */
435 		i2c_nuvoton_ready(chip);
436 		return rc;
437 	}
438 	/* execute the TPM command */
439 	rc = i2c_nuvoton_write_status(client, TPM_STS_GO);
440 	if (rc < 0) {
441 		dev_err(dev, "%s() fail to write Go\n", __func__);
442 		i2c_nuvoton_ready(chip);
443 		return rc;
444 	}
445 	ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
446 	duration = tpm_calc_ordinal_duration(chip, ordinal);
447 
448 	rc = i2c_nuvoton_wait_for_data_avail(chip, duration, &priv->read_queue);
449 	if (rc) {
450 		dev_err(dev, "%s() timeout command duration %ld\n",
451 			__func__, duration);
452 		i2c_nuvoton_ready(chip);
453 		return rc;
454 	}
455 
456 	dev_dbg(dev, "%s() -> %zd\n", __func__, len);
457 	return 0;
458 }
459 
460 static bool i2c_nuvoton_req_canceled(struct tpm_chip *chip, u8 status)
461 {
462 	return (status == TPM_STS_COMMAND_READY);
463 }
464 
465 static const struct tpm_class_ops tpm_i2c = {
466 	.flags = TPM_OPS_AUTO_STARTUP,
467 	.status = i2c_nuvoton_read_status,
468 	.recv = i2c_nuvoton_recv,
469 	.send = i2c_nuvoton_send,
470 	.cancel = i2c_nuvoton_ready,
471 	.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
472 	.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
473 	.req_canceled = i2c_nuvoton_req_canceled,
474 };
475 
476 /* The only purpose for the handler is to signal to any waiting threads that
477  * the interrupt is currently being asserted. The driver does not do any
478  * processing triggered by interrupts, and the chip provides no way to mask at
479  * the source (plus that would be slow over I2C). Run the IRQ as a one-shot,
480  * this means it cannot be shared. */
481 static irqreturn_t i2c_nuvoton_int_handler(int dummy, void *dev_id)
482 {
483 	struct tpm_chip *chip = dev_id;
484 	struct priv_data *priv = dev_get_drvdata(&chip->dev);
485 
486 	priv->intrs++;
487 	wake_up(&priv->read_queue);
488 	disable_irq_nosync(priv->irq);
489 	return IRQ_HANDLED;
490 }
491 
492 static int get_vid(struct i2c_client *client, u32 *res)
493 {
494 	static const u8 vid_did_rid_value[] = { 0x50, 0x10, 0xfe };
495 	u32 temp;
496 	s32 rc;
497 
498 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
499 		return -ENODEV;
500 	rc = i2c_nuvoton_read_buf(client, TPM_VID_DID_RID, 4, (u8 *)&temp);
501 	if (rc < 0)
502 		return rc;
503 
504 	/* check WPCT301 values - ignore RID */
505 	if (memcmp(&temp, vid_did_rid_value, sizeof(vid_did_rid_value))) {
506 		/*
507 		 * f/w rev 2.81 has an issue where the VID_DID_RID is not
508 		 * reporting the right value. so give it another chance at
509 		 * offset 0x20 (FIFO_W).
510 		 */
511 		rc = i2c_nuvoton_read_buf(client, TPM_DATA_FIFO_W, 4,
512 					  (u8 *) (&temp));
513 		if (rc < 0)
514 			return rc;
515 
516 		/* check WPCT301 values - ignore RID */
517 		if (memcmp(&temp, vid_did_rid_value,
518 			   sizeof(vid_did_rid_value)))
519 			return -ENODEV;
520 	}
521 
522 	*res = temp;
523 	return 0;
524 }
525 
526 static int i2c_nuvoton_probe(struct i2c_client *client)
527 {
528 	int rc;
529 	struct tpm_chip *chip;
530 	struct device *dev = &client->dev;
531 	struct priv_data *priv;
532 	u32 vid = 0;
533 
534 	rc = get_vid(client, &vid);
535 	if (rc)
536 		return rc;
537 
538 	dev_info(dev, "VID: %04X DID: %02X RID: %02X\n", (u16) vid,
539 		 (u8) (vid >> 16), (u8) (vid >> 24));
540 
541 	chip = tpmm_chip_alloc(dev, &tpm_i2c);
542 	if (IS_ERR(chip))
543 		return PTR_ERR(chip);
544 
545 	priv = devm_kzalloc(dev, sizeof(struct priv_data), GFP_KERNEL);
546 	if (!priv)
547 		return -ENOMEM;
548 
549 	if (i2c_get_match_data(client))
550 		chip->flags |= TPM_CHIP_FLAG_TPM2;
551 
552 	init_waitqueue_head(&priv->read_queue);
553 
554 	/* Default timeouts */
555 	chip->timeout_a = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
556 	chip->timeout_b = msecs_to_jiffies(TPM_I2C_LONG_TIMEOUT);
557 	chip->timeout_c = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
558 	chip->timeout_d = msecs_to_jiffies(TPM_I2C_SHORT_TIMEOUT);
559 
560 	dev_set_drvdata(&chip->dev, priv);
561 
562 	/*
563 	 * I2C intfcaps (interrupt capabilitieis) in the chip are hard coded to:
564 	 *   TPM_INTF_INT_LEVEL_LOW | TPM_INTF_DATA_AVAIL_INT
565 	 * The IRQ should be set in the i2c_board_info (which is done
566 	 * automatically in of_i2c_register_devices, for device tree users */
567 	priv->irq = client->irq;
568 	if (client->irq) {
569 		dev_dbg(dev, "%s() priv->irq\n", __func__);
570 		rc = devm_request_irq(dev, client->irq,
571 				      i2c_nuvoton_int_handler,
572 				      IRQF_TRIGGER_LOW,
573 				      dev_name(&chip->dev),
574 				      chip);
575 		if (rc) {
576 			dev_err(dev, "%s() Unable to request irq: %d for use\n",
577 				__func__, priv->irq);
578 			priv->irq = 0;
579 		} else {
580 			chip->flags |= TPM_CHIP_FLAG_IRQ;
581 			/* Clear any pending interrupt */
582 			i2c_nuvoton_ready(chip);
583 			/* - wait for TPM_STS==0xA0 (stsValid, commandReady) */
584 			rc = i2c_nuvoton_wait_for_stat(chip,
585 						       TPM_STS_COMMAND_READY,
586 						       TPM_STS_COMMAND_READY,
587 						       chip->timeout_b,
588 						       NULL);
589 			if (rc == 0) {
590 				/*
591 				 * TIS is in ready state
592 				 * write dummy byte to enter reception state
593 				 * TPM_DATA_FIFO_W <- rc (0)
594 				 */
595 				rc = i2c_nuvoton_write_buf(client,
596 							   TPM_DATA_FIFO_W,
597 							   1, (u8 *) (&rc));
598 				if (rc < 0)
599 					return rc;
600 				/* TPM_STS <- 0x40 (commandReady) */
601 				i2c_nuvoton_ready(chip);
602 			} else {
603 				/*
604 				 * timeout_b reached - command was
605 				 * aborted. TIS should now be in idle state -
606 				 * only TPM_STS_VALID should be set
607 				 */
608 				if (i2c_nuvoton_read_status(chip) !=
609 				    TPM_STS_VALID)
610 					return -EIO;
611 			}
612 		}
613 	}
614 
615 	return tpm_chip_register(chip);
616 }
617 
618 static void i2c_nuvoton_remove(struct i2c_client *client)
619 {
620 	struct tpm_chip *chip = i2c_get_clientdata(client);
621 
622 	tpm_chip_unregister(chip);
623 }
624 
625 static const struct i2c_device_id i2c_nuvoton_id[] = {
626 	{"tpm_i2c_nuvoton"},
627 	{"tpm2_i2c_nuvoton", .driver_data = I2C_IS_TPM2},
628 	{}
629 };
630 MODULE_DEVICE_TABLE(i2c, i2c_nuvoton_id);
631 
632 #ifdef CONFIG_OF
633 static const struct of_device_id i2c_nuvoton_of_match[] = {
634 	{.compatible = "nuvoton,npct501"},
635 	{.compatible = "winbond,wpct301"},
636 	{.compatible = "nuvoton,npct601", .data = OF_IS_TPM2},
637 	{},
638 };
639 MODULE_DEVICE_TABLE(of, i2c_nuvoton_of_match);
640 #endif
641 
642 static SIMPLE_DEV_PM_OPS(i2c_nuvoton_pm_ops, tpm_pm_suspend, tpm_pm_resume);
643 
644 static struct i2c_driver i2c_nuvoton_driver = {
645 	.id_table = i2c_nuvoton_id,
646 	.probe = i2c_nuvoton_probe,
647 	.remove = i2c_nuvoton_remove,
648 	.driver = {
649 		.name = "tpm_i2c_nuvoton",
650 		.pm = &i2c_nuvoton_pm_ops,
651 		.of_match_table = of_match_ptr(i2c_nuvoton_of_match),
652 	},
653 };
654 
655 module_i2c_driver(i2c_nuvoton_driver);
656 
657 MODULE_AUTHOR("Dan Morav <dan.morav@nuvoton.com>");
658 MODULE_DESCRIPTION("Nuvoton TPM I2C Driver");
659 MODULE_LICENSE("GPL");
660