1 files changed, 744 insertions, 0 deletions

diff --git a/drivers/watchdog/ziirave_wdt.c b/drivers/watchdog/ziirave_wdt.c
new file mode 100644
index 000000000..d0e888754
--- /dev/null
+++ b/drivers/watchdog/ziirave_wdt.c
@@ -0,0 +1,744 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * 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
+ */
+
+#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/watchdog.h>
+
+#include <asm/unaligned.h>
+
+#define ZIIRAVE_TIMEOUT_MIN	3
+#define ZIIRAVE_TIMEOUT_MAX	255
+#define ZIIRAVE_TIMEOUT_DEFAULT	30
+
+#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	(2 * 0x1600)
+#define ZIIRAVE_FIRM_FLASH_MEMORY_END	(2 * 0x2bbf)
+#define ZIIRAVE_FIRM_PAGE_SIZE		128
+
+/* Received and ready for next Download packet. */
+#define ZIIRAVE_FIRM_DOWNLOAD_ACK	1
+
+/* 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
+
+#define ZIIRAVE_CMD_JUMP_TO_BOOTLOADER_MAGIC	1
+#define ZIIRAVE_CMD_RESET_PROCESSOR_MAGIC	1
+
+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_read_ack(struct watchdog_device *wdd)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	int ret;
+
+	ret = i2c_smbus_read_byte(client);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to read status byte\n");
+		return ret;
+	}
+
+	return ret == ZIIRAVE_FIRM_DOWNLOAD_ACK ? 0 : -EIO;
+}
+
+static int ziirave_firm_set_read_addr(struct watchdog_device *wdd, u32 addr)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	const u16 addr16 = (u16)addr / 2;
+	u8 address[2];
+
+	put_unaligned_le16(addr16, address);
+
+	return i2c_smbus_write_block_data(client,
+					  ZIIRAVE_CMD_DOWNLOAD_SET_READ_ADDR,
+					  sizeof(address), address);
+}
+
+static bool ziirave_firm_addr_readonly(u32 addr)
+{
+	return addr < ZIIRAVE_FIRM_FLASH_MEMORY_START ||
+	       addr > ZIIRAVE_FIRM_FLASH_MEMORY_END;
+}
+
+/*
+ * 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,
+				    u32 addr, const u8 *data, u8 len)
+{
+	const u16 addr16 = (u16)addr / 2;
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	u8 i, checksum = 0, packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE];
+	int ret;
+
+	/* Check max data size */
+	if (len > ZIIRAVE_FIRM_PKT_DATA_SIZE) {
+		dev_err(&client->dev, "Firmware packet too long (%d)\n",
+			len);
+		return -EMSGSIZE;
+	}
+
+	/*
+	 * Ignore packets that are targeting program memory outisde of
+	 * app partition, since they will be ignored by the
+	 * bootloader. At the same time, we need to make sure we'll
+	 * allow zero length packet that will be sent as the last step
+	 * of firmware update
+	 */
+	if (len && ziirave_firm_addr_readonly(addr))
+		return 0;
+
+	/* Packet length */
+	packet[0] = len;
+	/* Packet address */
+	put_unaligned_le16(addr16, packet + 1);
+
+	memcpy(packet + 3, data, len);
+	memset(packet + 3 + len, 0, ZIIRAVE_FIRM_PKT_DATA_SIZE - len);
+
+	/* Packet checksum */
+	for (i = 0; i < len + 3; i++)
+		checksum += packet[i];
+	packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE - 1] = checksum;
+
+	ret = i2c_smbus_write_block_data(client, ZIIRAVE_CMD_DOWNLOAD_PACKET,
+					 sizeof(packet), packet);
+	if (ret) {
+		dev_err(&client->dev,
+			"Failed to send DOWNLOAD_PACKET: %d\n", ret);
+		return ret;
+	}
+
+	ret = ziirave_firm_read_ack(wdd);
+	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_write_pkt(struct watchdog_device *wdd,
+				  u32 addr, const u8 *data, u8 len)
+{
+	const u8 max_write_len = ZIIRAVE_FIRM_PAGE_SIZE -
+		(addr - ALIGN_DOWN(addr, ZIIRAVE_FIRM_PAGE_SIZE));
+	int ret;
+
+	if (len > max_write_len) {
+		/*
+		 * If data crossed page boundary we need to split this
+		 * write in two
+		 */
+		ret = __ziirave_firm_write_pkt(wdd, addr, data, max_write_len);
+		if (ret)
+			return ret;
+
+		addr += max_write_len;
+		data += max_write_len;
+		len  -= max_write_len;
+	}
+
+	return __ziirave_firm_write_pkt(wdd, addr, data, len);
+}
+
+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];
+
+	for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
+		const u16 len = be16_to_cpu(rec->len);
+		const u32 addr = be32_to_cpu(rec->addr);
+
+		if (ziirave_firm_addr_readonly(addr))
+			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 < len; 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, 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);
+	const struct ihex_binrec *rec;
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(client,
+					ZIIRAVE_CMD_JUMP_TO_BOOTLOADER,
+					ZIIRAVE_CMD_JUMP_TO_BOOTLOADER_MAGIC);
+	if (ret) {
+		dev_err(&client->dev, "Failed to jump to bootloader\n");
+		return ret;
+	}
+
+	msleep(500);
+
+	ret = i2c_smbus_write_byte(client, ZIIRAVE_CMD_DOWNLOAD_START);
+	if (ret) {
+		dev_err(&client->dev, "Failed to start download\n");
+		return ret;
+	}
+
+	ret = ziirave_firm_read_ack(wdd);
+	if (ret) {
+		dev_err(&client->dev, "No ACK for start download\n");
+		return ret;
+	}
+
+	msleep(500);
+
+	for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
+		ret = ziirave_firm_write_pkt(wdd, be32_to_cpu(rec->addr),
+					     rec->data, be16_to_cpu(rec->len));
+		if (ret)
+			return ret;
+	}
+
+	/*
+	 * Finish firmware download process by sending a zero length
+	 * payload
+	 */
+	ret = ziirave_firm_write_pkt(wdd, 0, NULL, 0);
+	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 = i2c_smbus_write_byte(client, ZIIRAVE_CMD_DOWNLOAD_END);
+	if (ret) {
+		dev_err(&client->dev,
+			"Failed to end firmware download: %d\n", ret);
+		return ret;
+	}
+
+	/* Reset the processor */
+	ret = i2c_smbus_write_byte_data(client,
+					ZIIRAVE_CMD_RESET_PROCESSOR,
+					ZIIRAVE_CMD_RESET_PROCESSOR_MAGIC);
+	if (ret) {
+		dev_err(&client->dev,
+			"Failed to reset the watchdog: %d\n", ret);
+		return ret;
+	}
+
+	msleep(500);
+
+	return 0;
+}
+
+static const struct watchdog_info ziirave_wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
+	.identity = "RAVE Switch 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 = sysfs_emit(buf, "02.%02u.%02u\n",
+			 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 = sysfs_emit(buf, "01.%02u.%02u\n",
+			 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 = sysfs_emit(buf, "%s\n", 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,
+			 "No reset pulse duration specified, 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 |
+				     I2C_FUNC_SMBUS_BYTE_DATA |
+				     I2C_FUNC_SMBUS_WRITE_BLOCK_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;
+
+	watchdog_init_timeout(&w_priv->wdd, wdt_timeout, &client->dev);
+
+	/*
+	 * 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) {
+			dev_err(&client->dev, "Failed to read timeout\n");
+			return val;
+		}
+
+		if (val > ZIIRAVE_TIMEOUT_MAX ||
+		    val < ZIIRAVE_TIMEOUT_MIN)
+			val = ZIIRAVE_TIMEOUT_DEFAULT;
+
+		w_priv->wdd.timeout = val;
+	}
+
+	ret = ziirave_wdt_set_timeout(&w_priv->wdd, w_priv->wdd.timeout);
+	if (ret) {
+		dev_err(&client->dev, "Failed to set timeout\n");
+		return ret;
+	}
+
+	dev_info(&client->dev, "Timeout set to %ds\n", 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) {
+		dev_err(&client->dev, "Failed to read state\n");
+		return val;
+	}
+
+	if (val == ZIIRAVE_STATE_INITIAL)
+		ziirave_wdt_stop(&w_priv->wdd);
+
+	ret = ziirave_wdt_init_duration(client);
+	if (ret) {
+		dev_err(&client->dev, "Failed to init duration\n");
+		return ret;
+	}
+
+	ret = ziirave_wdt_revision(client, &w_priv->firmware_rev,
+				   ZIIRAVE_WDT_FIRM_VER_MAJOR);
+	if (ret) {
+		dev_err(&client->dev, "Failed to read firmware version\n");
+		return ret;
+	}
+
+	dev_info(&client->dev,
+		 "Firmware version: 02.%02u.%02u\n",
+		 w_priv->firmware_rev.major, w_priv->firmware_rev.minor);
+
+	ret = ziirave_wdt_revision(client, &w_priv->bootloader_rev,
+				   ZIIRAVE_WDT_BOOT_VER_MAJOR);
+	if (ret) {
+		dev_err(&client->dev, "Failed to read bootloader version\n");
+		return ret;
+	}
+
+	dev_info(&client->dev,
+		 "Bootloader version: 01.%02u.%02u\n",
+		 w_priv->bootloader_rev.major, w_priv->bootloader_rev.minor);
+
+	w_priv->reset_reason = i2c_smbus_read_byte_data(client,
+						ZIIRAVE_WDT_RESET_REASON);
+	if (w_priv->reset_reason < 0) {
+		dev_err(&client->dev, "Failed to read reset reason\n");
+		return w_priv->reset_reason;
+	}
+
+	if (w_priv->reset_reason >= ARRAY_SIZE(ziirave_reasons) ||
+	    !ziirave_reasons[w_priv->reset_reason]) {
+		dev_err(&client->dev, "Invalid reset reason\n");
+		return -ENODEV;
+	}
+
+	ret = watchdog_register_device(&w_priv->wdd);
+
+	return ret;
+}
+
+static void ziirave_wdt_remove(struct i2c_client *client)
+{
+	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
+
+	watchdog_unregister_device(&w_priv->wdd);
+}
+
+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");