ziirave_wdt.c

  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 <linux/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
 37static 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
 72struct ziirave_wdt_rev {
 73	unsigned char major;
 74	unsigned char minor;
 75};
 76
 77struct 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
 85static int wdt_timeout;
 86module_param(wdt_timeout, int, 0);
 87MODULE_PARM_DESC(wdt_timeout, "Watchdog timeout in seconds");
 88
 89static int reset_duration;
 90module_param(reset_duration, int, 0);
 91MODULE_PARM_DESC(reset_duration,
 92		 "Watchdog reset pulse duration in milliseconds");
 93
 94static bool nowayout = WATCHDOG_NOWAYOUT;
 95module_param(nowayout, bool, 0);
 96MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started default="
 97		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 98
 99static 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
119static 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
126static int ziirave_wdt_start(struct watchdog_device *wdd)
127{
128	return ziirave_wdt_set_state(wdd, ZIIRAVE_STATE_ON);
129}
130
131static int ziirave_wdt_stop(struct watchdog_device *wdd)
132{
133	return ziirave_wdt_set_state(wdd, ZIIRAVE_STATE_OFF);
134}
135
136static 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
144static 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
157static 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
169static 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
183static 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
196static 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 */
214static 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
269static 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
293static 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 (len > sizeof(data))
306			return -EINVAL;
307
308		if (ziirave_firm_addr_readonly(addr))
309			continue;
310
311		ret = ziirave_firm_set_read_addr(wdd, addr);
312		if (ret) {
313			dev_err(&client->dev,
314				"Failed to send SET_READ_ADDR command: %d\n",
315				ret);
316			return ret;
317		}
318
319		for (i = 0; i < len; i++) {
320			ret = i2c_smbus_read_byte_data(client,
321						ZIIRAVE_CMD_DOWNLOAD_READ_BYTE);
322			if (ret < 0) {
323				dev_err(&client->dev,
324					"Failed to READ DATA: %d\n", ret);
325				return ret;
326			}
327			data[i] = ret;
328		}
329
330		if (memcmp(data, rec->data, len)) {
331			dev_err(&client->dev,
332				"Firmware mismatch at address 0x%04x\n", addr);
333			return -EINVAL;
334		}
335	}
336
337	return 0;
338}
339
340static int ziirave_firm_upload(struct watchdog_device *wdd,
341			       const struct firmware *fw)
342{
343	struct i2c_client *client = to_i2c_client(wdd->parent);
344	const struct ihex_binrec *rec;
345	int ret;
346
347	ret = i2c_smbus_write_byte_data(client,
348					ZIIRAVE_CMD_JUMP_TO_BOOTLOADER,
349					ZIIRAVE_CMD_JUMP_TO_BOOTLOADER_MAGIC);
350	if (ret) {
351		dev_err(&client->dev, "Failed to jump to bootloader\n");
352		return ret;
353	}
354
355	msleep(500);
356
357	ret = i2c_smbus_write_byte(client, ZIIRAVE_CMD_DOWNLOAD_START);
358	if (ret) {
359		dev_err(&client->dev, "Failed to start download\n");
360		return ret;
361	}
362
363	ret = ziirave_firm_read_ack(wdd);
364	if (ret) {
365		dev_err(&client->dev, "No ACK for start download\n");
366		return ret;
367	}
368
369	msleep(500);
370
371	for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
372		ret = ziirave_firm_write_pkt(wdd, be32_to_cpu(rec->addr),
373					     rec->data, be16_to_cpu(rec->len));
374		if (ret)
375			return ret;
376	}
377
378	/*
379	 * Finish firmware download process by sending a zero length
380	 * payload
381	 */
382	ret = ziirave_firm_write_pkt(wdd, 0, NULL, 0);
383	if (ret) {
384		dev_err(&client->dev, "Failed to send EMPTY packet: %d\n", ret);
385		return ret;
386	}
387
388	/* This sleep seems to be required */
389	msleep(20);
390
391	/* Start firmware verification */
392	ret = ziirave_firm_verify(wdd, fw);
393	if (ret) {
394		dev_err(&client->dev,
395			"Failed to verify firmware: %d\n", ret);
396		return ret;
397	}
398
399	/* End download operation */
400	ret = i2c_smbus_write_byte(client, ZIIRAVE_CMD_DOWNLOAD_END);
401	if (ret) {
402		dev_err(&client->dev,
403			"Failed to end firmware download: %d\n", ret);
404		return ret;
405	}
406
407	/* Reset the processor */
408	ret = i2c_smbus_write_byte_data(client,
409					ZIIRAVE_CMD_RESET_PROCESSOR,
410					ZIIRAVE_CMD_RESET_PROCESSOR_MAGIC);
411	if (ret) {
412		dev_err(&client->dev,
413			"Failed to reset the watchdog: %d\n", ret);
414		return ret;
415	}
416
417	msleep(500);
418
419	return 0;
420}
421
422static const struct watchdog_info ziirave_wdt_info = {
423	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
424	.identity = "RAVE Switch Watchdog",
425};
426
427static const struct watchdog_ops ziirave_wdt_ops = {
428	.owner		= THIS_MODULE,
429	.start		= ziirave_wdt_start,
430	.stop		= ziirave_wdt_stop,
431	.ping		= ziirave_wdt_ping,
432	.set_timeout	= ziirave_wdt_set_timeout,
433	.get_timeleft	= ziirave_wdt_get_timeleft,
434};
435
436static ssize_t ziirave_wdt_sysfs_show_firm(struct device *dev,
437					   struct device_attribute *attr,
438					   char *buf)
439{
440	struct i2c_client *client = to_i2c_client(dev->parent);
441	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
442	int ret;
443
444	ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
445	if (ret)
446		return ret;
447
448	ret = sysfs_emit(buf, "02.%02u.%02u\n",
449			 w_priv->firmware_rev.major,
450			 w_priv->firmware_rev.minor);
451
452	mutex_unlock(&w_priv->sysfs_mutex);
453
454	return ret;
455}
456
457static DEVICE_ATTR(firmware_version, S_IRUGO, ziirave_wdt_sysfs_show_firm,
458		   NULL);
459
460static ssize_t ziirave_wdt_sysfs_show_boot(struct device *dev,
461					   struct device_attribute *attr,
462					   char *buf)
463{
464	struct i2c_client *client = to_i2c_client(dev->parent);
465	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
466	int ret;
467
468	ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
469	if (ret)
470		return ret;
471
472	ret = sysfs_emit(buf, "01.%02u.%02u\n",
473			 w_priv->bootloader_rev.major,
474			 w_priv->bootloader_rev.minor);
475
476	mutex_unlock(&w_priv->sysfs_mutex);
477
478	return ret;
479}
480
481static DEVICE_ATTR(bootloader_version, S_IRUGO, ziirave_wdt_sysfs_show_boot,
482		   NULL);
483
484static ssize_t ziirave_wdt_sysfs_show_reason(struct device *dev,
485					     struct device_attribute *attr,
486					     char *buf)
487{
488	struct i2c_client *client = to_i2c_client(dev->parent);
489	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
490	int ret;
491
492	ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
493	if (ret)
494		return ret;
495
496	ret = sysfs_emit(buf, "%s\n", ziirave_reasons[w_priv->reset_reason]);
497
498	mutex_unlock(&w_priv->sysfs_mutex);
499
500	return ret;
501}
502
503static DEVICE_ATTR(reset_reason, S_IRUGO, ziirave_wdt_sysfs_show_reason,
504		   NULL);
505
506static ssize_t ziirave_wdt_sysfs_store_firm(struct device *dev,
507					    struct device_attribute *attr,
508					    const char *buf, size_t count)
509{
510	struct i2c_client *client = to_i2c_client(dev->parent);
511	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
512	const struct firmware *fw;
513	int err;
514
515	err = request_ihex_firmware(&fw, ZIIRAVE_FW_NAME, dev);
516	if (err) {
517		dev_err(&client->dev, "Failed to request ihex firmware\n");
518		return err;
519	}
520
521	err = mutex_lock_interruptible(&w_priv->sysfs_mutex);
522	if (err)
523		goto release_firmware;
524
525	err = ziirave_firm_upload(&w_priv->wdd, fw);
526	if (err) {
527		dev_err(&client->dev, "The firmware update failed: %d\n", err);
528		goto unlock_mutex;
529	}
530
531	/* Update firmware version */
532	err = ziirave_wdt_revision(client, &w_priv->firmware_rev,
533				   ZIIRAVE_WDT_FIRM_VER_MAJOR);
534	if (err) {
535		dev_err(&client->dev, "Failed to read firmware version: %d\n",
536			err);
537		goto unlock_mutex;
538	}
539
540	dev_info(&client->dev,
541		 "Firmware updated to version 02.%02u.%02u\n",
542		 w_priv->firmware_rev.major, w_priv->firmware_rev.minor);
543
544	/* Restore the watchdog timeout */
545	err = ziirave_wdt_set_timeout(&w_priv->wdd, w_priv->wdd.timeout);
546	if (err)
547		dev_err(&client->dev, "Failed to set timeout: %d\n", err);
548
549unlock_mutex:
550	mutex_unlock(&w_priv->sysfs_mutex);
551
552release_firmware:
553	release_firmware(fw);
554
555	return err ? err : count;
556}
557
558static DEVICE_ATTR(update_firmware, S_IWUSR, NULL,
559		   ziirave_wdt_sysfs_store_firm);
560
561static struct attribute *ziirave_wdt_attrs[] = {
562	&dev_attr_firmware_version.attr,
563	&dev_attr_bootloader_version.attr,
564	&dev_attr_reset_reason.attr,
565	&dev_attr_update_firmware.attr,
566	NULL
567};
568ATTRIBUTE_GROUPS(ziirave_wdt);
569
570static int ziirave_wdt_init_duration(struct i2c_client *client)
571{
572	int ret;
573
574	if (!reset_duration) {
575		/* See if the reset pulse duration is provided in an of_node */
576		if (!client->dev.of_node)
577			ret = -ENODEV;
578		else
579			ret = of_property_read_u32(client->dev.of_node,
580						   "reset-duration-ms",
581						   &reset_duration);
582		if (ret) {
583			dev_info(&client->dev,
584			 "No reset pulse duration specified, using default\n");
585			return 0;
586		}
587	}
588
589	if (reset_duration < 1 || reset_duration > 255)
590		return -EINVAL;
591
592	dev_info(&client->dev, "Setting reset duration to %dms",
593		 reset_duration);
594
595	return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_RESET_DURATION,
596					 reset_duration);
597}
598
599static int ziirave_wdt_probe(struct i2c_client *client)
600{
601	int ret;
602	struct ziirave_wdt_data *w_priv;
603	int val;
604
605	if (!i2c_check_functionality(client->adapter,
606				     I2C_FUNC_SMBUS_BYTE |
607				     I2C_FUNC_SMBUS_BYTE_DATA |
608				     I2C_FUNC_SMBUS_WRITE_BLOCK_DATA))
609		return -ENODEV;
610
611	w_priv = devm_kzalloc(&client->dev, sizeof(*w_priv), GFP_KERNEL);
612	if (!w_priv)
613		return -ENOMEM;
614
615	mutex_init(&w_priv->sysfs_mutex);
616
617	w_priv->wdd.info = &ziirave_wdt_info;
618	w_priv->wdd.ops = &ziirave_wdt_ops;
619	w_priv->wdd.min_timeout = ZIIRAVE_TIMEOUT_MIN;
620	w_priv->wdd.max_timeout = ZIIRAVE_TIMEOUT_MAX;
621	w_priv->wdd.parent = &client->dev;
622	w_priv->wdd.groups = ziirave_wdt_groups;
623
624	watchdog_init_timeout(&w_priv->wdd, wdt_timeout, &client->dev);
625
626	/*
627	 * The default value set in the watchdog should be perfectly valid, so
628	 * pass that in if we haven't provided one via the module parameter or
629	 * of property.
630	 */
631	if (w_priv->wdd.timeout == 0) {
632		val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_TIMEOUT);
633		if (val < 0) {
634			dev_err(&client->dev, "Failed to read timeout\n");
635			return val;
636		}
637
638		if (val > ZIIRAVE_TIMEOUT_MAX ||
639		    val < ZIIRAVE_TIMEOUT_MIN)
640			val = ZIIRAVE_TIMEOUT_DEFAULT;
641
642		w_priv->wdd.timeout = val;
643	}
644
645	ret = ziirave_wdt_set_timeout(&w_priv->wdd, w_priv->wdd.timeout);
646	if (ret) {
647		dev_err(&client->dev, "Failed to set timeout\n");
648		return ret;
649	}
650
651	dev_info(&client->dev, "Timeout set to %ds\n", w_priv->wdd.timeout);
652
653	watchdog_set_nowayout(&w_priv->wdd, nowayout);
654
655	i2c_set_clientdata(client, w_priv);
656
657	/* If in unconfigured state, set to stopped */
658	val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_STATE);
659	if (val < 0) {
660		dev_err(&client->dev, "Failed to read state\n");
661		return val;
662	}
663
664	if (val == ZIIRAVE_STATE_INITIAL)
665		ziirave_wdt_stop(&w_priv->wdd);
666
667	ret = ziirave_wdt_init_duration(client);
668	if (ret) {
669		dev_err(&client->dev, "Failed to init duration\n");
670		return ret;
671	}
672
673	ret = ziirave_wdt_revision(client, &w_priv->firmware_rev,
674				   ZIIRAVE_WDT_FIRM_VER_MAJOR);
675	if (ret) {
676		dev_err(&client->dev, "Failed to read firmware version\n");
677		return ret;
678	}
679
680	dev_info(&client->dev,
681		 "Firmware version: 02.%02u.%02u\n",
682		 w_priv->firmware_rev.major, w_priv->firmware_rev.minor);
683
684	ret = ziirave_wdt_revision(client, &w_priv->bootloader_rev,
685				   ZIIRAVE_WDT_BOOT_VER_MAJOR);
686	if (ret) {
687		dev_err(&client->dev, "Failed to read bootloader version\n");
688		return ret;
689	}
690
691	dev_info(&client->dev,
692		 "Bootloader version: 01.%02u.%02u\n",
693		 w_priv->bootloader_rev.major, w_priv->bootloader_rev.minor);
694
695	w_priv->reset_reason = i2c_smbus_read_byte_data(client,
696						ZIIRAVE_WDT_RESET_REASON);
697	if (w_priv->reset_reason < 0) {
698		dev_err(&client->dev, "Failed to read reset reason\n");
699		return w_priv->reset_reason;
700	}
701
702	if (w_priv->reset_reason >= ARRAY_SIZE(ziirave_reasons) ||
703	    !ziirave_reasons[w_priv->reset_reason]) {
704		dev_err(&client->dev, "Invalid reset reason\n");
705		return -ENODEV;
706	}
707
708	ret = watchdog_register_device(&w_priv->wdd);
709
710	return ret;
711}
712
713static void ziirave_wdt_remove(struct i2c_client *client)
714{
715	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
716
717	watchdog_unregister_device(&w_priv->wdd);
718}
719
720static const struct i2c_device_id ziirave_wdt_id[] = {
721	{ "rave-wdt" },
722	{ }
723};
724MODULE_DEVICE_TABLE(i2c, ziirave_wdt_id);
725
726static const struct of_device_id zrv_wdt_of_match[] = {
727	{ .compatible = "zii,rave-wdt", },
728	{ },
729};
730MODULE_DEVICE_TABLE(of, zrv_wdt_of_match);
731
732static 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
742module_i2c_driver(ziirave_wdt_driver);
743
744MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk");
745MODULE_DESCRIPTION("Zodiac Aerospace RAVE Switch Watchdog Processor Driver");
746MODULE_LICENSE("GPL");