1 files changed, 766 insertions, 0 deletions

diff --git a/drivers/watchdog/ziirave_wdt.c b/drivers/watchdog/ziirave_wdt.c
new file mode 100644
index 000000000..d3594aa3a
--- /dev/null
+++ b/drivers/watchdog/ziirave_wdt.c
@@ -0,0 +1,766 @@
+/*
+ * Copyright (C) 2015 Zodiac Inflight Innovations
+ *
+ * Author: Martyn Welch <martyn.welch@collabora.co.uk>
+ *
+ * Based on twl4030_wdt.c by Timo Kokkonen <timo.t.kokkonen at nokia.com>:
+ *
+ * Copyright (C) Nokia Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/ihex.h>
+#include <linux/firmware.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+#include <linux/version.h>
+#include <linux/watchdog.h>
+
+#define ZIIRAVE_TIMEOUT_MIN	3
+#define ZIIRAVE_TIMEOUT_MAX	255
+
+#define ZIIRAVE_PING_VALUE	0x0
+
+#define ZIIRAVE_STATE_INITIAL	0x0
+#define ZIIRAVE_STATE_OFF	0x1
+#define ZIIRAVE_STATE_ON	0x2
+
+#define ZIIRAVE_FW_NAME		"ziirave_wdt.fw"
+
+static char *ziirave_reasons[] = {"power cycle", "hw watchdog", NULL, NULL,
+				  "host request", NULL, "illegal configuration",
+				  "illegal instruction", "illegal trap",
+				  "unknown"};
+
+#define ZIIRAVE_WDT_FIRM_VER_MAJOR	0x1
+#define ZIIRAVE_WDT_BOOT_VER_MAJOR	0x3
+#define ZIIRAVE_WDT_RESET_REASON	0x5
+#define ZIIRAVE_WDT_STATE		0x6
+#define ZIIRAVE_WDT_TIMEOUT		0x7
+#define ZIIRAVE_WDT_TIME_LEFT		0x8
+#define ZIIRAVE_WDT_PING		0x9
+#define ZIIRAVE_WDT_RESET_DURATION	0xa
+
+#define ZIIRAVE_FIRM_PKT_TOTAL_SIZE	20
+#define ZIIRAVE_FIRM_PKT_DATA_SIZE	16
+#define ZIIRAVE_FIRM_FLASH_MEMORY_START	0x1600
+#define ZIIRAVE_FIRM_FLASH_MEMORY_END	0x2bbf
+
+/* Received and ready for next Download packet. */
+#define ZIIRAVE_FIRM_DOWNLOAD_ACK	1
+/* Currently writing to flash. Retry Download status in a moment! */
+#define ZIIRAVE_FIRM_DOWNLOAD_BUSY	2
+
+/* Wait for ACK timeout in ms */
+#define ZIIRAVE_FIRM_WAIT_FOR_ACK_TIMEOUT	50
+
+/* Firmware commands */
+#define ZIIRAVE_CMD_DOWNLOAD_START		0x10
+#define ZIIRAVE_CMD_DOWNLOAD_END		0x11
+#define ZIIRAVE_CMD_DOWNLOAD_SET_READ_ADDR	0x12
+#define ZIIRAVE_CMD_DOWNLOAD_READ_BYTE		0x13
+#define ZIIRAVE_CMD_RESET_PROCESSOR		0x0b
+#define ZIIRAVE_CMD_JUMP_TO_BOOTLOADER		0x0c
+#define ZIIRAVE_CMD_DOWNLOAD_PACKET		0x0e
+
+struct ziirave_wdt_rev {
+	unsigned char major;
+	unsigned char minor;
+};
+
+struct ziirave_wdt_data {
+	struct mutex sysfs_mutex;
+	struct watchdog_device wdd;
+	struct ziirave_wdt_rev bootloader_rev;
+	struct ziirave_wdt_rev firmware_rev;
+	int reset_reason;
+};
+
+static int wdt_timeout;
+module_param(wdt_timeout, int, 0);
+MODULE_PARM_DESC(wdt_timeout, "Watchdog timeout in seconds");
+
+static int reset_duration;
+module_param(reset_duration, int, 0);
+MODULE_PARM_DESC(reset_duration,
+		 "Watchdog reset pulse duration in milliseconds");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started default="
+		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static int ziirave_wdt_revision(struct i2c_client *client,
+				struct ziirave_wdt_rev *rev, u8 command)
+{
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(client, command);
+	if (ret < 0)
+		return ret;
+
+	rev->major = ret;
+
+	ret = i2c_smbus_read_byte_data(client, command + 1);
+	if (ret < 0)
+		return ret;
+
+	rev->minor = ret;
+
+	return 0;
+}
+
+static int ziirave_wdt_set_state(struct watchdog_device *wdd, int state)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+
+	return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_STATE, state);
+}
+
+static int ziirave_wdt_start(struct watchdog_device *wdd)
+{
+	return ziirave_wdt_set_state(wdd, ZIIRAVE_STATE_ON);
+}
+
+static int ziirave_wdt_stop(struct watchdog_device *wdd)
+{
+	return ziirave_wdt_set_state(wdd, ZIIRAVE_STATE_OFF);
+}
+
+static int ziirave_wdt_ping(struct watchdog_device *wdd)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+
+	return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_PING,
+					 ZIIRAVE_PING_VALUE);
+}
+
+static int ziirave_wdt_set_timeout(struct watchdog_device *wdd,
+				   unsigned int timeout)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_TIMEOUT, timeout);
+	if (!ret)
+		wdd->timeout = timeout;
+
+	return ret;
+}
+
+static unsigned int ziirave_wdt_get_timeleft(struct watchdog_device *wdd)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_TIME_LEFT);
+	if (ret < 0)
+		ret = 0;
+
+	return ret;
+}
+
+static int ziirave_firm_wait_for_ack(struct watchdog_device *wdd)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	int ret;
+	unsigned long timeout;
+
+	timeout = jiffies + msecs_to_jiffies(ZIIRAVE_FIRM_WAIT_FOR_ACK_TIMEOUT);
+	do {
+		if (time_after(jiffies, timeout))
+			return -ETIMEDOUT;
+
+		usleep_range(5000, 10000);
+
+		ret = i2c_smbus_read_byte(client);
+		if (ret < 0) {
+			dev_err(&client->dev, "Failed to read byte\n");
+			return ret;
+		}
+	} while (ret == ZIIRAVE_FIRM_DOWNLOAD_BUSY);
+
+	return ret == ZIIRAVE_FIRM_DOWNLOAD_ACK ? 0 : -EIO;
+}
+
+static int ziirave_firm_set_read_addr(struct watchdog_device *wdd, u16 addr)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	u8 address[2];
+
+	address[0] = addr & 0xff;
+	address[1] = (addr >> 8) & 0xff;
+
+	return i2c_smbus_write_block_data(client,
+					  ZIIRAVE_CMD_DOWNLOAD_SET_READ_ADDR,
+					  ARRAY_SIZE(address), address);
+}
+
+static int ziirave_firm_write_block_data(struct watchdog_device *wdd,
+					 u8 command, u8 length, const u8 *data,
+					 bool wait_for_ack)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	int ret;
+
+	ret = i2c_smbus_write_block_data(client, command, length, data);
+	if (ret) {
+		dev_err(&client->dev,
+			"Failed to send command 0x%02x: %d\n", command, ret);
+		return ret;
+	}
+
+	if (wait_for_ack)
+		ret = ziirave_firm_wait_for_ack(wdd);
+
+	return ret;
+}
+
+static int ziirave_firm_write_byte(struct watchdog_device *wdd, u8 command,
+				   u8 byte, bool wait_for_ack)
+{
+	return ziirave_firm_write_block_data(wdd, command, 1, &byte,
+					     wait_for_ack);
+}
+
+/*
+ * ziirave_firm_write_pkt() - Build and write a firmware packet
+ *
+ * A packet to send to the firmware is composed by following bytes:
+ *     Length | Addr0 | Addr1 | Data0 .. Data15 | Checksum |
+ * Where,
+ *     Length: A data byte containing the length of the data.
+ *     Addr0: Low byte of the address.
+ *     Addr1: High byte of the address.
+ *     Data0 .. Data15: Array of 16 bytes of data.
+ *     Checksum: Checksum byte to verify data integrity.
+ */
+static int ziirave_firm_write_pkt(struct watchdog_device *wdd,
+				  const struct ihex_binrec *rec)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	u8 i, checksum = 0, packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE];
+	int ret;
+	u16 addr;
+
+	memset(packet, 0, ARRAY_SIZE(packet));
+
+	/* Packet length */
+	packet[0] = (u8)be16_to_cpu(rec->len);
+	/* Packet address */
+	addr = (be32_to_cpu(rec->addr) & 0xffff) >> 1;
+	packet[1] = addr & 0xff;
+	packet[2] = (addr & 0xff00) >> 8;
+
+	/* Packet data */
+	if (be16_to_cpu(rec->len) > ZIIRAVE_FIRM_PKT_DATA_SIZE)
+		return -EMSGSIZE;
+	memcpy(packet + 3, rec->data, be16_to_cpu(rec->len));
+
+	/* Packet checksum */
+	for (i = 0; i < ZIIRAVE_FIRM_PKT_TOTAL_SIZE - 1; i++)
+		checksum += packet[i];
+	packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE - 1] = checksum;
+
+	ret = ziirave_firm_write_block_data(wdd, ZIIRAVE_CMD_DOWNLOAD_PACKET,
+					    ARRAY_SIZE(packet), packet, true);
+	if (ret)
+		dev_err(&client->dev,
+		      "Failed to write firmware packet at address 0x%04x: %d\n",
+		      addr, ret);
+
+	return ret;
+}
+
+static int ziirave_firm_verify(struct watchdog_device *wdd,
+			       const struct firmware *fw)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	const struct ihex_binrec *rec;
+	int i, ret;
+	u8 data[ZIIRAVE_FIRM_PKT_DATA_SIZE];
+	u16 addr;
+
+	for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
+		/* Zero length marks end of records */
+		if (!be16_to_cpu(rec->len))
+			break;
+
+		addr = (be32_to_cpu(rec->addr) & 0xffff) >> 1;
+		if (addr < ZIIRAVE_FIRM_FLASH_MEMORY_START ||
+		    addr > ZIIRAVE_FIRM_FLASH_MEMORY_END)
+			continue;
+
+		ret = ziirave_firm_set_read_addr(wdd, addr);
+		if (ret) {
+			dev_err(&client->dev,
+				"Failed to send SET_READ_ADDR command: %d\n",
+				ret);
+			return ret;
+		}
+
+		for (i = 0; i < ARRAY_SIZE(data); i++) {
+			ret = i2c_smbus_read_byte_data(client,
+						ZIIRAVE_CMD_DOWNLOAD_READ_BYTE);
+			if (ret < 0) {
+				dev_err(&client->dev,
+					"Failed to READ DATA: %d\n", ret);
+				return ret;
+			}
+			data[i] = ret;
+		}
+
+		if (memcmp(data, rec->data, be16_to_cpu(rec->len))) {
+			dev_err(&client->dev,
+				"Firmware mismatch at address 0x%04x\n", addr);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int ziirave_firm_upload(struct watchdog_device *wdd,
+			       const struct firmware *fw)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	int ret, words_till_page_break;
+	const struct ihex_binrec *rec;
+	struct ihex_binrec *rec_new;
+
+	ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_JUMP_TO_BOOTLOADER, 1,
+				      false);
+	if (ret)
+		return ret;
+
+	msleep(500);
+
+	ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_DOWNLOAD_START, 1, true);
+	if (ret)
+		return ret;
+
+	msleep(500);
+
+	for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
+		/* Zero length marks end of records */
+		if (!be16_to_cpu(rec->len))
+			break;
+
+		/* Check max data size */
+		if (be16_to_cpu(rec->len) > ZIIRAVE_FIRM_PKT_DATA_SIZE) {
+			dev_err(&client->dev, "Firmware packet too long (%d)\n",
+				be16_to_cpu(rec->len));
+			return -EMSGSIZE;
+		}
+
+		/* Calculate words till page break */
+		words_till_page_break = (64 - ((be32_to_cpu(rec->addr) >> 1) &
+					 0x3f));
+		if ((be16_to_cpu(rec->len) >> 1) > words_till_page_break) {
+			/*
+			 * Data in passes page boundary, so we need to split in
+			 * two blocks of data. Create a packet with the first
+			 * block of data.
+			 */
+			rec_new = kzalloc(sizeof(struct ihex_binrec) +
+					  (words_till_page_break << 1),
+					  GFP_KERNEL);
+			if (!rec_new)
+				return -ENOMEM;
+
+			rec_new->len = cpu_to_be16(words_till_page_break << 1);
+			rec_new->addr = rec->addr;
+			memcpy(rec_new->data, rec->data,
+			       be16_to_cpu(rec_new->len));
+
+			ret = ziirave_firm_write_pkt(wdd, rec_new);
+			kfree(rec_new);
+			if (ret)
+				return ret;
+
+			/* Create a packet with the second block of data */
+			rec_new = kzalloc(sizeof(struct ihex_binrec) +
+					  be16_to_cpu(rec->len) -
+					  (words_till_page_break << 1),
+					  GFP_KERNEL);
+			if (!rec_new)
+				return -ENOMEM;
+
+			/* Remaining bytes */
+			rec_new->len = rec->len -
+				       cpu_to_be16(words_till_page_break << 1);
+
+			rec_new->addr = cpu_to_be32(be32_to_cpu(rec->addr) +
+					(words_till_page_break << 1));
+
+			memcpy(rec_new->data,
+			       rec->data + (words_till_page_break << 1),
+			       be16_to_cpu(rec_new->len));
+
+			ret = ziirave_firm_write_pkt(wdd, rec_new);
+			kfree(rec_new);
+			if (ret)
+				return ret;
+		} else {
+			ret = ziirave_firm_write_pkt(wdd, rec);
+			if (ret)
+				return ret;
+		}
+	}
+
+	/* For end of download, the length field will be set to 0 */
+	rec_new = kzalloc(sizeof(struct ihex_binrec) + 1, GFP_KERNEL);
+	if (!rec_new)
+		return -ENOMEM;
+
+	ret = ziirave_firm_write_pkt(wdd, rec_new);
+	kfree(rec_new);
+	if (ret) {
+		dev_err(&client->dev, "Failed to send EMPTY packet: %d\n", ret);
+		return ret;
+	}
+
+	/* This sleep seems to be required */
+	msleep(20);
+
+	/* Start firmware verification */
+	ret = ziirave_firm_verify(wdd, fw);
+	if (ret) {
+		dev_err(&client->dev,
+			"Failed to verify firmware: %d\n", ret);
+		return ret;
+	}
+
+	/* End download operation */
+	ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_DOWNLOAD_END, 1, false);
+	if (ret)
+		return ret;
+
+	/* Reset the processor */
+	ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_RESET_PROCESSOR, 1,
+				      false);
+	if (ret)
+		return ret;
+
+	msleep(500);
+
+	return 0;
+}
+
+static const struct watchdog_info ziirave_wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
+	.identity = "Zodiac RAVE Watchdog",
+};
+
+static const struct watchdog_ops ziirave_wdt_ops = {
+	.owner		= THIS_MODULE,
+	.start		= ziirave_wdt_start,
+	.stop		= ziirave_wdt_stop,
+	.ping		= ziirave_wdt_ping,
+	.set_timeout	= ziirave_wdt_set_timeout,
+	.get_timeleft	= ziirave_wdt_get_timeleft,
+};
+
+static ssize_t ziirave_wdt_sysfs_show_firm(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
+	int ret;
+
+	ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
+	if (ret)
+		return ret;
+
+	ret = sprintf(buf, "02.%02u.%02u", w_priv->firmware_rev.major,
+		      w_priv->firmware_rev.minor);
+
+	mutex_unlock(&w_priv->sysfs_mutex);
+
+	return ret;
+}
+
+static DEVICE_ATTR(firmware_version, S_IRUGO, ziirave_wdt_sysfs_show_firm,
+		   NULL);
+
+static ssize_t ziirave_wdt_sysfs_show_boot(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
+	int ret;
+
+	ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
+	if (ret)
+		return ret;
+
+	ret = sprintf(buf, "01.%02u.%02u", w_priv->bootloader_rev.major,
+		      w_priv->bootloader_rev.minor);
+
+	mutex_unlock(&w_priv->sysfs_mutex);
+
+	return ret;
+}
+
+static DEVICE_ATTR(bootloader_version, S_IRUGO, ziirave_wdt_sysfs_show_boot,
+		   NULL);
+
+static ssize_t ziirave_wdt_sysfs_show_reason(struct device *dev,
+					     struct device_attribute *attr,
+					     char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
+	int ret;
+
+	ret = mutex_lock_interruptible(&w_priv->sysfs_mutex);
+	if (ret)
+		return ret;
+
+	ret = sprintf(buf, "%s", ziirave_reasons[w_priv->reset_reason]);
+
+	mutex_unlock(&w_priv->sysfs_mutex);
+
+	return ret;
+}
+
+static DEVICE_ATTR(reset_reason, S_IRUGO, ziirave_wdt_sysfs_show_reason,
+		   NULL);
+
+static ssize_t ziirave_wdt_sysfs_store_firm(struct device *dev,
+					    struct device_attribute *attr,
+					    const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
+	const struct firmware *fw;
+	int err;
+
+	err = request_ihex_firmware(&fw, ZIIRAVE_FW_NAME, dev);
+	if (err) {
+		dev_err(&client->dev, "Failed to request ihex firmware\n");
+		return err;
+	}
+
+	err = mutex_lock_interruptible(&w_priv->sysfs_mutex);
+	if (err)
+		goto release_firmware;
+
+	err = ziirave_firm_upload(&w_priv->wdd, fw);
+	if (err) {
+		dev_err(&client->dev, "The firmware update failed: %d\n", err);
+		goto unlock_mutex;
+	}
+
+	/* Update firmware version */
+	err = ziirave_wdt_revision(client, &w_priv->firmware_rev,
+				   ZIIRAVE_WDT_FIRM_VER_MAJOR);
+	if (err) {
+		dev_err(&client->dev, "Failed to read firmware version: %d\n",
+			err);
+		goto unlock_mutex;
+	}
+
+	dev_info(&client->dev, "Firmware updated to version 02.%02u.%02u\n",
+		 w_priv->firmware_rev.major, w_priv->firmware_rev.minor);
+
+	/* Restore the watchdog timeout */
+	err = ziirave_wdt_set_timeout(&w_priv->wdd, w_priv->wdd.timeout);
+	if (err)
+		dev_err(&client->dev, "Failed to set timeout: %d\n", err);
+
+unlock_mutex:
+	mutex_unlock(&w_priv->sysfs_mutex);
+
+release_firmware:
+	release_firmware(fw);
+
+	return err ? err : count;
+}
+
+static DEVICE_ATTR(update_firmware, S_IWUSR, NULL,
+		   ziirave_wdt_sysfs_store_firm);
+
+static struct attribute *ziirave_wdt_attrs[] = {
+	&dev_attr_firmware_version.attr,
+	&dev_attr_bootloader_version.attr,
+	&dev_attr_reset_reason.attr,
+	&dev_attr_update_firmware.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(ziirave_wdt);
+
+static int ziirave_wdt_init_duration(struct i2c_client *client)
+{
+	int ret;
+
+	if (!reset_duration) {
+		/* See if the reset pulse duration is provided in an of_node */
+		if (!client->dev.of_node)
+			ret = -ENODEV;
+		else
+			ret = of_property_read_u32(client->dev.of_node,
+						   "reset-duration-ms",
+						   &reset_duration);
+		if (ret) {
+			dev_info(&client->dev,
+				 "Unable to set reset pulse duration, using default\n");
+			return 0;
+		}
+	}
+
+	if (reset_duration < 1 || reset_duration > 255)
+		return -EINVAL;
+
+	dev_info(&client->dev, "Setting reset duration to %dms",
+		 reset_duration);
+
+	return i2c_smbus_write_byte_data(client, ZIIRAVE_WDT_RESET_DURATION,
+					 reset_duration);
+}
+
+static int ziirave_wdt_probe(struct i2c_client *client,
+			     const struct i2c_device_id *id)
+{
+	int ret;
+	struct ziirave_wdt_data *w_priv;
+	int val;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -ENODEV;
+
+	w_priv = devm_kzalloc(&client->dev, sizeof(*w_priv), GFP_KERNEL);
+	if (!w_priv)
+		return -ENOMEM;
+
+	mutex_init(&w_priv->sysfs_mutex);
+
+	w_priv->wdd.info = &ziirave_wdt_info;
+	w_priv->wdd.ops = &ziirave_wdt_ops;
+	w_priv->wdd.min_timeout = ZIIRAVE_TIMEOUT_MIN;
+	w_priv->wdd.max_timeout = ZIIRAVE_TIMEOUT_MAX;
+	w_priv->wdd.parent = &client->dev;
+	w_priv->wdd.groups = ziirave_wdt_groups;
+
+	ret = watchdog_init_timeout(&w_priv->wdd, wdt_timeout, &client->dev);
+	if (ret) {
+		dev_info(&client->dev,
+			 "Unable to select timeout value, using default\n");
+	}
+
+	/*
+	 * The default value set in the watchdog should be perfectly valid, so
+	 * pass that in if we haven't provided one via the module parameter or
+	 * of property.
+	 */
+	if (w_priv->wdd.timeout == 0) {
+		val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_TIMEOUT);
+		if (val < 0)
+			return val;
+
+		if (val < ZIIRAVE_TIMEOUT_MIN)
+			return -ENODEV;
+
+		w_priv->wdd.timeout = val;
+	} else {
+		ret = ziirave_wdt_set_timeout(&w_priv->wdd,
+					      w_priv->wdd.timeout);
+		if (ret)
+			return ret;
+
+		dev_info(&client->dev, "Timeout set to %ds.",
+			 w_priv->wdd.timeout);
+	}
+
+	watchdog_set_nowayout(&w_priv->wdd, nowayout);
+
+	i2c_set_clientdata(client, w_priv);
+
+	/* If in unconfigured state, set to stopped */
+	val = i2c_smbus_read_byte_data(client, ZIIRAVE_WDT_STATE);
+	if (val < 0)
+		return val;
+
+	if (val == ZIIRAVE_STATE_INITIAL)
+		ziirave_wdt_stop(&w_priv->wdd);
+
+	ret = ziirave_wdt_init_duration(client);
+	if (ret)
+		return ret;
+
+	ret = ziirave_wdt_revision(client, &w_priv->firmware_rev,
+				   ZIIRAVE_WDT_FIRM_VER_MAJOR);
+	if (ret)
+		return ret;
+
+	ret = ziirave_wdt_revision(client, &w_priv->bootloader_rev,
+				   ZIIRAVE_WDT_BOOT_VER_MAJOR);
+	if (ret)
+		return ret;
+
+	w_priv->reset_reason = i2c_smbus_read_byte_data(client,
+						ZIIRAVE_WDT_RESET_REASON);
+	if (w_priv->reset_reason < 0)
+		return w_priv->reset_reason;
+
+	if (w_priv->reset_reason >= ARRAY_SIZE(ziirave_reasons) ||
+	    !ziirave_reasons[w_priv->reset_reason])
+		return -ENODEV;
+
+	ret = watchdog_register_device(&w_priv->wdd);
+
+	return ret;
+}
+
+static int ziirave_wdt_remove(struct i2c_client *client)
+{
+	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
+
+	watchdog_unregister_device(&w_priv->wdd);
+
+	return 0;
+}
+
+static const struct i2c_device_id ziirave_wdt_id[] = {
+	{ "rave-wdt", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ziirave_wdt_id);
+
+static const struct of_device_id zrv_wdt_of_match[] = {
+	{ .compatible = "zii,rave-wdt", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, zrv_wdt_of_match);
+
+static struct i2c_driver ziirave_wdt_driver = {
+	.driver = {
+		.name = "ziirave_wdt",
+		.of_match_table = zrv_wdt_of_match,
+	},
+	.probe = ziirave_wdt_probe,
+	.remove = ziirave_wdt_remove,
+	.id_table = ziirave_wdt_id,
+};
+
+module_i2c_driver(ziirave_wdt_driver);
+
+MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk");
+MODULE_DESCRIPTION("Zodiac Aerospace RAVE Switch Watchdog Processor Driver");
+MODULE_LICENSE("GPL");