watchdog: Zodiac Aerospace RAVE Switch Watchdog Processor Driver

This patch adds a driver for the Zodiac Aerospace RAVE Watchdog Procesor.
This device implements a watchdog timer, accessible over I2C.
Signed-off-by: Martyn Welch <martyn.welch@collabora.co.uk>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/Kconfig

@@ -168,6 +168,17 @@ config XILINX_WATCHDOG
 	  To compile this driver as a module, choose M here: the
 	  module will be called of_xilinx_wdt.
 
+config ZIIRAVE_WATCHDOG
+	tristate "Zodiac RAVE Watchdog Timer"
+	depends on I2C
+	select WATCHDOG_CORE
+	help
+	  Watchdog driver for the Zodiac Aerospace RAVE Switch Watchdog
+	  Processor.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ziirave_wdt.
+
 # ALPHA Architecture
 
 # ARM Architecture

drivers/watchdog/Makefile

@@ -193,5 +193,6 @@ obj-$(CONFIG_GPIO_WATCHDOG)	+= gpio_wdt.o
 obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
 obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
 obj-$(CONFIG_MAX63XX_WATCHDOG) += max63xx_wdt.o
+obj-$(CONFIG_ZIIRAVE_WATCHDOG) += ziirave_wdt.o
 obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
 obj-$(CONFIG_MENF21BMC_WATCHDOG) += menf21bmc_wdt.o

drivers/watchdog/ziirave_wdt.c

+/*
+ * 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/i2c.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
+
+static char *ziirave_reasons[] = {"power cycle", "triggered", 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
+
+struct ziirave_wdt_rev {
+	unsigned char major;
+	unsigned char minor;
+};
+
+struct ziirave_wdt_data {
+	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 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);
+
+	return sprintf(buf, "02.%02u.%02u", w_priv->firmware_rev.major,
+		       w_priv->firmware_rev.minor);
+}
+
+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);
+
+	return sprintf(buf, "01.%02u.%02u", w_priv->bootloader_rev.major,
+		       w_priv->bootloader_rev.minor);
+}
+
+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);
+
+	return sprintf(buf, "%s", ziirave_reasons[w_priv->reset_reason]);
+}
+
+static DEVICE_ATTR(reset_reason, S_IRUGO, ziirave_wdt_sysfs_show_reason,
+		   NULL);
+
+static struct attribute *ziirave_wdt_attrs[] = {
+	&dev_attr_firmware_version.attr,
+	&dev_attr_bootloader_version.attr,
+	&dev_attr_reset_reason.attr,
+	NULL
+};
+
+static const struct attribute_group ziirave_wdt_sysfs_files = {
+	.attrs  = ziirave_wdt_attrs,
+};
+
+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;
+
+	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;
+
+	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);
+	if (ret)
+		return ret;
+
+	ret = sysfs_create_group(&w_priv->wdd.dev->kobj,
+				 &ziirave_wdt_sysfs_files);
+	if (ret) {
+		watchdog_unregister_device(&w_priv->wdd);
+
+		return ret;
+	}
+
+	return 0;
+}
+
+static int ziirave_wdt_remove(struct i2c_client *client)
+{
+	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
+
+	sysfs_remove_group(&client->dev.kobj, &ziirave_wdt_sysfs_files);
+
+	watchdog_unregister_device(&w_priv->wdd);
+
+	return 0;
+}
+
+static struct i2c_device_id ziirave_wdt_id[] = {
+	{ "ziirave-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");