1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2015 Zodiac Inflight Innovations
4  *
5  * Author: Martyn Welch <martyn.welch@collabora.co.uk>
6  *
7  * Based on twl4030_wdt.c by Timo Kokkonen <timo.t.kokkonen at nokia.com>:
8  *
9  * Copyright (C) Nokia Corporation
10  */
11 
12 #include <linux/delay.h>
13 #include <linux/i2c.h>
14 #include <linux/ihex.h>
15 #include <linux/firmware.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/sysfs.h>
20 #include <linux/types.h>
21 #include <linux/watchdog.h>
22 
23 #include <asm/unaligned.h>
24 
25 #define ZIIRAVE_TIMEOUT_MIN	3
26 #define ZIIRAVE_TIMEOUT_MAX	255
27 #define ZIIRAVE_TIMEOUT_DEFAULT	30
28 
29 #define ZIIRAVE_PING_VALUE	0x0
30 
31 #define ZIIRAVE_STATE_INITIAL	0x0
32 #define ZIIRAVE_STATE_OFF	0x1
33 #define ZIIRAVE_STATE_ON	0x2
34 
35 #define ZIIRAVE_FW_NAME		"ziirave_wdt.fw"
36 
37 static char *ziirave_reasons[] = {"power cycle", "hw watchdog", NULL, NULL,
38 				  "host request", NULL, "illegal configuration",
39 				  "illegal instruction", "illegal trap",
40 				  "unknown"};
41 
42 #define ZIIRAVE_WDT_FIRM_VER_MAJOR	0x1
43 #define ZIIRAVE_WDT_BOOT_VER_MAJOR	0x3
44 #define ZIIRAVE_WDT_RESET_REASON	0x5
45 #define ZIIRAVE_WDT_STATE		0x6
46 #define ZIIRAVE_WDT_TIMEOUT		0x7
47 #define ZIIRAVE_WDT_TIME_LEFT		0x8
48 #define ZIIRAVE_WDT_PING		0x9
49 #define ZIIRAVE_WDT_RESET_DURATION	0xa
50 
51 #define ZIIRAVE_FIRM_PKT_TOTAL_SIZE	20
52 #define ZIIRAVE_FIRM_PKT_DATA_SIZE	16
53 #define ZIIRAVE_FIRM_FLASH_MEMORY_START	(2 * 0x1600)
54 #define ZIIRAVE_FIRM_FLASH_MEMORY_END	(2 * 0x2bbf)
55 #define ZIIRAVE_FIRM_PAGE_SIZE		128
56 
57 /* Received and ready for next Download packet. */
58 #define ZIIRAVE_FIRM_DOWNLOAD_ACK	1
59 
60 /* Firmware commands */
61 #define ZIIRAVE_CMD_DOWNLOAD_START		0x10
62 #define ZIIRAVE_CMD_DOWNLOAD_END		0x11
63 #define ZIIRAVE_CMD_DOWNLOAD_SET_READ_ADDR	0x12
64 #define ZIIRAVE_CMD_DOWNLOAD_READ_BYTE		0x13
65 #define ZIIRAVE_CMD_RESET_PROCESSOR		0x0b
66 #define ZIIRAVE_CMD_JUMP_TO_BOOTLOADER		0x0c
67 #define ZIIRAVE_CMD_DOWNLOAD_PACKET		0x0e
68 
69 #define ZIIRAVE_CMD_JUMP_TO_BOOTLOADER_MAGIC	1
70 #define ZIIRAVE_CMD_RESET_PROCESSOR_MAGIC	1
71 
72 struct ziirave_wdt_rev {
73 	unsigned char major;
74 	unsigned char minor;
75 };
76 
77 struct ziirave_wdt_data {
78 	struct mutex sysfs_mutex;
79 	struct watchdog_device wdd;
80 	struct ziirave_wdt_rev bootloader_rev;
81 	struct ziirave_wdt_rev firmware_rev;
82 	int reset_reason;
83 };
84 
85 static int wdt_timeout;
86 module_param(wdt_timeout, int, 0);
87 MODULE_PARM_DESC(wdt_timeout, "Watchdog timeout in seconds");
88 
89 static int reset_duration;
90 module_param(reset_duration, int, 0);
91 MODULE_PARM_DESC(reset_duration,
92 		 "Watchdog reset pulse duration in milliseconds");
93 
94 static bool nowayout = WATCHDOG_NOWAYOUT;
95 module_param(nowayout, bool, 0);
96 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started default="
97 		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
98 
99 static int ziirave_wdt_revision(struct i2c_client *client,
100 				struct ziirave_wdt_rev *rev, u8 command)
101 {
102 	int ret;
103 
104 	ret = i2c_smbus_read_byte_data(client, command);
105 	if (ret < 0)
106 		return ret;
107 
108 	rev->major = ret;
109 
110 	ret = i2c_smbus_read_byte_data(client, command + 1);
111 	if (ret < 0)
112 		return ret;
113 
114 	rev->minor = ret;
115 
116 	return 0;
117 }
118 
119 static int ziirave_wdt_set_state(struct watchdog_device *wdd, int state)
120 {
121 	struct i2c_client *client = to_i2c_client(wdd->parent);
122 
123 	return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_STATE, state);
124 }
125 
126 static int ziirave_wdt_start(struct watchdog_device *wdd)
127 {
128 	return ziirave_wdt_set_state(wdd, ZIIRAVE_STATE_ON);
129 }
130 
131 static int ziirave_wdt_stop(struct watchdog_device *wdd)
132 {
133 	return ziirave_wdt_set_state(wdd, ZIIRAVE_STATE_OFF);
134 }
135 
136 static int ziirave_wdt_ping(struct watchdog_device *wdd)
137 {
138 	struct i2c_client *client = to_i2c_client(wdd->parent);
139 
140 	return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_PING,
141 					 ZIIRAVE_PING_VALUE);
142 }
143 
144 static int ziirave_wdt_set_timeout(struct watchdog_device *wdd,
145 				   unsigned int timeout)
146 {
147 	struct i2c_client *client = to_i2c_client(wdd->parent);
148 	int ret;
149 
150 	ret = i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_TIMEOUT, timeout);
151 	if (!ret)
152 		wdd->timeout = timeout;
153 
154 	return ret;
155 }
156 
157 static unsigned int ziirave_wdt_get_timeleft(struct watchdog_device *wdd)
158 {
159 	struct i2c_client *client = to_i2c_client(wdd->parent);
160 	int ret;
161 
162 	ret = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_TIME_LEFT);
163 	if (ret < 0)
164 		ret = 0;
165 
166 	return ret;
167 }
168 
169 static int ziirave_firm_read_ack(struct watchdog_device *wdd)
170 {
171 	struct i2c_client *client = to_i2c_client(wdd->parent);
172 	int ret;
173 
174 	ret = i2c_smbus_read_byte(client);
175 	if (ret < 0) {
176 		dev_err(&client->dev, "Failed to read status byte\n");
177 		return ret;
178 	}
179 
180 	return ret == ZIIRAVE_FIRM_DOWNLOAD_ACK ? 0 : -EIO;
181 }
182 
183 static int ziirave_firm_set_read_addr(struct watchdog_device *wdd, u32 addr)
184 {
185 	struct i2c_client *client = to_i2c_client(wdd->parent);
186 	const u16 addr16 = (u16)addr / 2;
187 	u8 address[2];
188 
189 	put_unaligned_le16(addr16, address);
190 
191 	return i2c_smbus_write_block_data(client,
192 					  ZIIRAVE_CMD_DOWNLOAD_SET_READ_ADDR,
193 					  sizeof(address), address);
194 }
195 
196 static bool ziirave_firm_addr_readonly(u32 addr)
197 {
198 	return addr < ZIIRAVE_FIRM_FLASH_MEMORY_START ||
199 	       addr > ZIIRAVE_FIRM_FLASH_MEMORY_END;
200 }
201 
202 /*
203  * ziirave_firm_write_pkt() - Build and write a firmware packet
204  *
205  * A packet to send to the firmware is composed by following bytes:
206  *     Length | Addr0 | Addr1 | Data0 .. Data15 | Checksum |
207  * Where,
208  *     Length: A data byte containing the length of the data.
209  *     Addr0: Low byte of the address.
210  *     Addr1: High byte of the address.
211  *     Data0 .. Data15: Array of 16 bytes of data.
212  *     Checksum: Checksum byte to verify data integrity.
213  */
214 static int __ziirave_firm_write_pkt(struct watchdog_device *wdd,
215 				    u32 addr, const u8 *data, u8 len)
216 {
217 	const u16 addr16 = (u16)addr / 2;
218 	struct i2c_client *client = to_i2c_client(wdd->parent);
219 	u8 i, checksum = 0, packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE];
220 	int ret;
221 
222 	/* Check max data size */
223 	if (len > ZIIRAVE_FIRM_PKT_DATA_SIZE) {
224 		dev_err(&client->dev, "Firmware packet too long (%d)\n",
225 			len);
226 		return -EMSGSIZE;
227 	}
228 
229 	/*
230 	 * Ignore packets that are targeting program memory outisde of
231 	 * app partition, since they will be ignored by the
232 	 * bootloader. At the same time, we need to make sure we'll
233 	 * allow zero length packet that will be sent as the last step
234 	 * of firmware update
235 	 */
236 	if (len && ziirave_firm_addr_readonly(addr))
237 		return 0;
238 
239 	/* Packet length */
240 	packet[0] = len;
241 	/* Packet address */
242 	put_unaligned_le16(addr16, packet + 1);
243 
244 	memcpy(packet + 3, data, len);
245 	memset(packet + 3 + len, 0, ZIIRAVE_FIRM_PKT_DATA_SIZE - len);
246 
247 	/* Packet checksum */
248 	for (i = 0; i < len + 3; i++)
249 		checksum += packet[i];
250 	packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE - 1] = checksum;
251 
252 	ret = i2c_smbus_write_block_data(client, ZIIRAVE_CMD_DOWNLOAD_PACKET,
253 					 sizeof(packet), packet);
254 	if (ret) {
255 		dev_err(&client->dev,
256 			"Failed to send DOWNLOAD_PACKET: %d\n", ret);
257 		return ret;
258 	}
259 
260 	ret = ziirave_firm_read_ack(wdd);
261 	if (ret)
262 		dev_err(&client->dev,
263 		      "Failed to write firmware packet at address 0x%04x: %d\n",
264 		      addr, ret);
265 
266 	return ret;
267 }
268 
269 static int ziirave_firm_write_pkt(struct watchdog_device *wdd,
270 				  u32 addr, const u8 *data, u8 len)
271 {
272 	const u8 max_write_len = ZIIRAVE_FIRM_PAGE_SIZE -
273 		(addr - ALIGN_DOWN(addr, ZIIRAVE_FIRM_PAGE_SIZE));
274 	int ret;
275 
276 	if (len > max_write_len) {
277 		/*
278 		 * If data crossed page boundary we need to split this
279 		 * write in two
280 		 */
281 		ret = __ziirave_firm_write_pkt(wdd, addr, data, max_write_len);
282 		if (ret)
283 			return ret;
284 
285 		addr += max_write_len;
286 		data += max_write_len;
287 		len  -= max_write_len;
288 	}
289 
290 	return __ziirave_firm_write_pkt(wdd, addr, data, len);
291 }
292 
293 static int ziirave_firm_verify(struct watchdog_device *wdd,
294 			       const struct firmware *fw)
295 {
296 	struct i2c_client *client = to_i2c_client(wdd->parent);
297 	const struct ihex_binrec *rec;
298 	int i, ret;
299 	u8 data[ZIIRAVE_FIRM_PKT_DATA_SIZE];
300 
301 	for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
302 		const u16 len = be16_to_cpu(rec->len);
303 		const u32 addr = be32_to_cpu(rec->addr);
304 
305 		if (ziirave_firm_addr_readonly(addr))
306 			continue;
307 
308 		ret = ziirave_firm_set_read_addr(wdd, addr);
309 		if (ret) {
310 			dev_err(&client->dev,
311 				"Failed to send SET_READ_ADDR command: %d\n",
312 				ret);
313 			return ret;
314 		}
315 
316 		for (i = 0; i < len; i++) {
317 			ret = i2c_smbus_read_byte_data(client,
318 						ZIIRAVE_CMD_DOWNLOAD_READ_BYTE);
319 			if (ret < 0) {
320 				dev_err(&client->dev,
321 					"Failed to READ DATA: %d\n", ret);
322 				return ret;
323 			}
324 			data[i] = ret;
325 		}
326 
327 		if (memcmp(data, rec->data, len)) {
328 			dev_err(&client->dev,
329 				"Firmware mismatch at address 0x%04x\n", addr);
330 			return -EINVAL;
331 		}
332 	}
333 
334 	return 0;
335 }
336 
337 static int ziirave_firm_upload(struct watchdog_device *wdd,
338 			       const struct firmware *fw)
339 {
340 	struct i2c_client *client = to_i2c_client(wdd->parent);
341 	const struct ihex_binrec *rec;
342 	int ret;
343 
344 	ret = i2c_smbus_write_byte_data(client,
345 					ZIIRAVE_CMD_JUMP_TO_BOOTLOADER,
346 					ZIIRAVE_CMD_JUMP_TO_BOOTLOADER_MAGIC);
347 	if (ret) {
348 		dev_err(&client->dev, "Failed to jump to bootloader\n");
349 		return ret;
350 	}
351 
352 	msleep(500);
353 
354 	ret = i2c_smbus_write_byte(client, ZIIRAVE_CMD_DOWNLOAD_START);
355 	if (ret) {
356 		dev_err(&client->dev, "Failed to start download\n");
357 		return ret;
358 	}
359 
360 	ret = ziirave_firm_read_ack(wdd);
361 	if (ret) {
362 		dev_err(&client->dev, "No ACK for start download\n");
363 		return ret;
364 	}
365 
366 	msleep(500);
367 
368 	for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
369 		ret = ziirave_firm_write_pkt(wdd, be32_to_cpu(rec->addr),
370 					     rec->data, be16_to_cpu(rec->len));
371 		if (ret)
372 			return ret;
373 	}
374 
375 	/*
376 	 * Finish firmware download process by sending a zero length
377 	 * payload
378 	 */
379 	ret = ziirave_firm_write_pkt(wdd, 0, NULL, 0);
380 	if (ret) {
381 		dev_err(&client->dev, "Failed to send EMPTY packet: %d\n", ret);
382 		return ret;
383 	}
384 
385 	/* This sleep seems to be required */
386 	msleep(20);
387 
388 	/* Start firmware verification */
389 	ret = ziirave_firm_verify(wdd, fw);
390 	if (ret) {
391 		dev_err(&client->dev,
392 			"Failed to verify firmware: %d\n", ret);
393 		return ret;
394 	}
395 
396 	/* End download operation */
397 	ret = i2c_smbus_write_byte(client, ZIIRAVE_CMD_DOWNLOAD_END);
398 	if (ret) {
399 		dev_err(&client->dev,
400 			"Failed to end firmware download: %d\n", ret);
401 		return ret;
402 	}
403 
404 	/* Reset the processor */
405 	ret = i2c_smbus_write_byte_data(client,
406 					ZIIRAVE_CMD_RESET_PROCESSOR,
407 					ZIIRAVE_CMD_RESET_PROCESSOR_MAGIC);
408 	if (ret) {
409 		dev_err(&client->dev,
410 			"Failed to reset the watchdog: %d\n", ret);
411 		return ret;
412 	}
413 
414 	msleep(500);
415 
416 	return 0;
417 }
418 
419 static const struct watchdog_info ziirave_wdt_info = {
420 	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
421 	.identity = "RAVE Switch Watchdog",
422 };
423 
424 static const struct watchdog_ops ziirave_wdt_ops = {
425 	.owner		= THIS_MODULE,
426 	.start		= ziirave_wdt_start,
427 	.stop		= ziirave_wdt_stop,
428 	.ping		= ziirave_wdt_ping,
429 	.set_timeout	= ziirave_wdt_set_timeout,
430 	.get_timeleft	= ziirave_wdt_get_timeleft,
431 };
432 
433 static ssize_t ziirave_wdt_sysfs_show_firm(struct device *dev,
434 					   struct device_attribute *attr,
435 					   char *buf)
436 {
437 	struct i2c_client *client = to_i2c_client(dev->parent);
438 	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
439 	int ret;
440 
441 	ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
442 	if (ret)
443 		return ret;
444 
445 	ret = sysfs_emit(buf, "02.%02u.%02u\n",
446 			 w_priv->firmware_rev.major,
447 			 w_priv->firmware_rev.minor);
448 
449 	mutex_unlock(&w_priv->sysfs_mutex);
450 
451 	return ret;
452 }
453 
454 static DEVICE_ATTR(firmware_version, S_IRUGO, ziirave_wdt_sysfs_show_firm,
455 		   NULL);
456 
457 static ssize_t ziirave_wdt_sysfs_show_boot(struct device *dev,
458 					   struct device_attribute *attr,
459 					   char *buf)
460 {
461 	struct i2c_client *client = to_i2c_client(dev->parent);
462 	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
463 	int ret;
464 
465 	ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
466 	if (ret)
467 		return ret;
468 
469 	ret = sysfs_emit(buf, "01.%02u.%02u\n",
470 			 w_priv->bootloader_rev.major,
471 			 w_priv->bootloader_rev.minor);
472 
473 	mutex_unlock(&w_priv->sysfs_mutex);
474 
475 	return ret;
476 }
477 
478 static DEVICE_ATTR(bootloader_version, S_IRUGO, ziirave_wdt_sysfs_show_boot,
479 		   NULL);
480 
481 static ssize_t ziirave_wdt_sysfs_show_reason(struct device *dev,
482 					     struct device_attribute *attr,
483 					     char *buf)
484 {
485 	struct i2c_client *client = to_i2c_client(dev->parent);
486 	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
487 	int ret;
488 
489 	ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
490 	if (ret)
491 		return ret;
492 
493 	ret = sysfs_emit(buf, "%s\n", ziirave_reasons[w_priv->reset_reason]);
494 
495 	mutex_unlock(&w_priv->sysfs_mutex);
496 
497 	return ret;
498 }
499 
500 static DEVICE_ATTR(reset_reason, S_IRUGO, ziirave_wdt_sysfs_show_reason,
501 		   NULL);
502 
503 static ssize_t ziirave_wdt_sysfs_store_firm(struct device *dev,
504 					    struct device_attribute *attr,
505 					    const char *buf, size_t count)
506 {
507 	struct i2c_client *client = to_i2c_client(dev->parent);
508 	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
509 	const struct firmware *fw;
510 	int err;
511 
512 	err = request_ihex_firmware(&fw, ZIIRAVE_FW_NAME, dev);
513 	if (err) {
514 		dev_err(&client->dev, "Failed to request ihex firmware\n");
515 		return err;
516 	}
517 
518 	err = mutex_lock_interruptible(&w_priv->sysfs_mutex);
519 	if (err)
520 		goto release_firmware;
521 
522 	err = ziirave_firm_upload(&w_priv->wdd, fw);
523 	if (err) {
524 		dev_err(&client->dev, "The firmware update failed: %d\n", err);
525 		goto unlock_mutex;
526 	}
527 
528 	/* Update firmware version */
529 	err = ziirave_wdt_revision(client, &w_priv->firmware_rev,
530 				   ZIIRAVE_WDT_FIRM_VER_MAJOR);
531 	if (err) {
532 		dev_err(&client->dev, "Failed to read firmware version: %d\n",
533 			err);
534 		goto unlock_mutex;
535 	}
536 
537 	dev_info(&client->dev,
538 		 "Firmware updated to version 02.%02u.%02u\n",
539 		 w_priv->firmware_rev.major, w_priv->firmware_rev.minor);
540 
541 	/* Restore the watchdog timeout */
542 	err = ziirave_wdt_set_timeout(&w_priv->wdd, w_priv->wdd.timeout);
543 	if (err)
544 		dev_err(&client->dev, "Failed to set timeout: %d\n", err);
545 
546 unlock_mutex:
547 	mutex_unlock(&w_priv->sysfs_mutex);
548 
549 release_firmware:
550 	release_firmware(fw);
551 
552 	return err ? err : count;
553 }
554 
555 static DEVICE_ATTR(update_firmware, S_IWUSR, NULL,
556 		   ziirave_wdt_sysfs_store_firm);
557 
558 static struct attribute *ziirave_wdt_attrs[] = {
559 	&dev_attr_firmware_version.attr,
560 	&dev_attr_bootloader_version.attr,
561 	&dev_attr_reset_reason.attr,
562 	&dev_attr_update_firmware.attr,
563 	NULL
564 };
565 ATTRIBUTE_GROUPS(ziirave_wdt);
566 
567 static int ziirave_wdt_init_duration(struct i2c_client *client)
568 {
569 	int ret;
570 
571 	if (!reset_duration) {
572 		/* See if the reset pulse duration is provided in an of_node */
573 		if (!client->dev.of_node)
574 			ret = -ENODEV;
575 		else
576 			ret = of_property_read_u32(client->dev.of_node,
577 						   "reset-duration-ms",
578 						   &reset_duration);
579 		if (ret) {
580 			dev_info(&client->dev,
581 			 "No reset pulse duration specified, using default\n");
582 			return 0;
583 		}
584 	}
585 
586 	if (reset_duration < 1 || reset_duration > 255)
587 		return -EINVAL;
588 
589 	dev_info(&client->dev, "Setting reset duration to %dms",
590 		 reset_duration);
591 
592 	return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_RESET_DURATION,
593 					 reset_duration);
594 }
595 
596 static int ziirave_wdt_probe(struct i2c_client *client,
597 			     const struct i2c_device_id *id)
598 {
599 	int ret;
600 	struct ziirave_wdt_data *w_priv;
601 	int val;
602 
603 	if (!i2c_check_functionality(client->adapter,
604 				     I2C_FUNC_SMBUS_BYTE |
605 				     I2C_FUNC_SMBUS_BYTE_DATA |
606 				     I2C_FUNC_SMBUS_WRITE_BLOCK_DATA))
607 		return -ENODEV;
608 
609 	w_priv = devm_kzalloc(&client->dev, sizeof(*w_priv), GFP_KERNEL);
610 	if (!w_priv)
611 		return -ENOMEM;
612 
613 	mutex_init(&w_priv->sysfs_mutex);
614 
615 	w_priv->wdd.info = &ziirave_wdt_info;
616 	w_priv->wdd.ops = &ziirave_wdt_ops;
617 	w_priv->wdd.min_timeout = ZIIRAVE_TIMEOUT_MIN;
618 	w_priv->wdd.max_timeout = ZIIRAVE_TIMEOUT_MAX;
619 	w_priv->wdd.parent = &client->dev;
620 	w_priv->wdd.groups = ziirave_wdt_groups;
621 
622 	watchdog_init_timeout(&w_priv->wdd, wdt_timeout, &client->dev);
623 
624 	/*
625 	 * The default value set in the watchdog should be perfectly valid, so
626 	 * pass that in if we haven't provided one via the module parameter or
627 	 * of property.
628 	 */
629 	if (w_priv->wdd.timeout == 0) {
630 		val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_TIMEOUT);
631 		if (val < 0) {
632 			dev_err(&client->dev, "Failed to read timeout\n");
633 			return val;
634 		}
635 
636 		if (val > ZIIRAVE_TIMEOUT_MAX ||
637 		    val < ZIIRAVE_TIMEOUT_MIN)
638 			val = ZIIRAVE_TIMEOUT_DEFAULT;
639 
640 		w_priv->wdd.timeout = val;
641 	}
642 
643 	ret = ziirave_wdt_set_timeout(&w_priv->wdd, w_priv->wdd.timeout);
644 	if (ret) {
645 		dev_err(&client->dev, "Failed to set timeout\n");
646 		return ret;
647 	}
648 
649 	dev_info(&client->dev, "Timeout set to %ds\n", w_priv->wdd.timeout);
650 
651 	watchdog_set_nowayout(&w_priv->wdd, nowayout);
652 
653 	i2c_set_clientdata(client, w_priv);
654 
655 	/* If in unconfigured state, set to stopped */
656 	val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_STATE);
657 	if (val < 0) {
658 		dev_err(&client->dev, "Failed to read state\n");
659 		return val;
660 	}
661 
662 	if (val == ZIIRAVE_STATE_INITIAL)
663 		ziirave_wdt_stop(&w_priv->wdd);
664 
665 	ret = ziirave_wdt_init_duration(client);
666 	if (ret) {
667 		dev_err(&client->dev, "Failed to init duration\n");
668 		return ret;
669 	}
670 
671 	ret = ziirave_wdt_revision(client, &w_priv->firmware_rev,
672 				   ZIIRAVE_WDT_FIRM_VER_MAJOR);
673 	if (ret) {
674 		dev_err(&client->dev, "Failed to read firmware version\n");
675 		return ret;
676 	}
677 
678 	dev_info(&client->dev,
679 		 "Firmware version: 02.%02u.%02u\n",
680 		 w_priv->firmware_rev.major, w_priv->firmware_rev.minor);
681 
682 	ret = ziirave_wdt_revision(client, &w_priv->bootloader_rev,
683 				   ZIIRAVE_WDT_BOOT_VER_MAJOR);
684 	if (ret) {
685 		dev_err(&client->dev, "Failed to read bootloader version\n");
686 		return ret;
687 	}
688 
689 	dev_info(&client->dev,
690 		 "Bootloader version: 01.%02u.%02u\n",
691 		 w_priv->bootloader_rev.major, w_priv->bootloader_rev.minor);
692 
693 	w_priv->reset_reason = i2c_smbus_read_byte_data(client,
694 						ZIIRAVE_WDT_RESET_REASON);
695 	if (w_priv->reset_reason < 0) {
696 		dev_err(&client->dev, "Failed to read reset reason\n");
697 		return w_priv->reset_reason;
698 	}
699 
700 	if (w_priv->reset_reason >= ARRAY_SIZE(ziirave_reasons) ||
701 	    !ziirave_reasons[w_priv->reset_reason]) {
702 		dev_err(&client->dev, "Invalid reset reason\n");
703 		return -ENODEV;
704 	}
705 
706 	ret = watchdog_register_device(&w_priv->wdd);
707 
708 	return ret;
709 }
710 
711 static int ziirave_wdt_remove(struct i2c_client *client)
712 {
713 	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
714 
715 	watchdog_unregister_device(&w_priv->wdd);
716 
717 	return 0;
718 }
719 
720 static const struct i2c_device_id ziirave_wdt_id[] = {
721 	{ "rave-wdt", 0 },
722 	{ }
723 };
724 MODULE_DEVICE_TABLE(i2c, ziirave_wdt_id);
725 
726 static const struct of_device_id zrv_wdt_of_match[] = {
727 	{ .compatible = "zii,rave-wdt", },
728 	{ },
729 };
730 MODULE_DEVICE_TABLE(of, zrv_wdt_of_match);
731 
732 static struct i2c_driver ziirave_wdt_driver = {
733 	.driver = {
734 		.name = "ziirave_wdt",
735 		.of_match_table = zrv_wdt_of_match,
736 	},
737 	.probe = ziirave_wdt_probe,
738 	.remove = ziirave_wdt_remove,
739 	.id_table = ziirave_wdt_id,
740 };
741 
742 module_i2c_driver(ziirave_wdt_driver);
743 
744 MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk");
745 MODULE_DESCRIPTION("Zodiac Aerospace RAVE Switch Watchdog Processor Driver");
746 MODULE_LICENSE("GPL");
747