Commit faa58475 authored by Guenter Roeck's avatar Guenter Roeck Committed by Wim Van Sebroeck
Browse files

watchdog: Add support for creating driver specific sysfs attributes 



The Zodiac watchdog driver attaches additional sysfs attributes to the
watchdog device. This has a number of problems: The watchdog device
lifetime differs from the driver lifetime, and the device structure
should therefore not be accessed from drivers. Also, creating sysfs
attributes after driver registration results in a potential race condition
if user space expects the attributes to exist but they don't exist yet.

Add support for creating driver specific sysfs attributes to the watchdog
core to solve the problems.

Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
parent 62cd1c40

Documentation/watchdog/watchdog-kernel-api.txt

+3 −0
Original line number Diff line number Diff line
@@ -46,6 +46,7 @@ struct watchdog_device { 
	int id;

	struct device *dev;

	struct device *parent;

	const struct attribute_group **groups;

	const struct watchdog_info *info;

	const struct watchdog_ops *ops;

	unsigned int bootstatus;
@@ -68,6 +69,8 @@ It contains following fields: 
* dev: device under the watchdog class (created by watchdog_register_device).

* parent: set this to the parent device (or NULL) before calling

  watchdog_register_device.

* groups: List of sysfs attribute groups to create when creating the watchdog

  device.

* info: a pointer to a watchdog_info structure. This structure gives some

  additional information about the watchdog timer itself. (Like it's unique name)

* ops: a pointer to the list of watchdog operations that the watchdog supports.

drivers/watchdog/watchdog_dev.c

+3 −2
Original line number Diff line number Diff line
@@ -744,7 +744,8 @@ int watchdog_dev_register(struct watchdog_device *wdd) 
	if (ret)

		return ret;



	dev = device_create(&watchdog_class, wdd->parent, devno, wdd,

	dev = device_create_with_groups(&watchdog_class, wdd->parent,

					devno, wdd, wdd->groups,

					"watchdog%d", wdd->id);

	if (IS_ERR(dev)) {

		watchdog_cdev_unregister(wdd);

include/linux/watchdog.h

+3 −0
Original line number Diff line number Diff line
@@ -55,6 +55,8 @@ struct watchdog_ops { 
 * @id:		The watchdog's ID. (Allocated by watchdog_register_device)

 * @dev:	The device for our watchdog

 * @parent:	The parent bus device

 * @groups:	List of sysfs attribute groups to create when creating the

 *		watchdog device.

 * @info:	Pointer to a watchdog_info structure.

 * @ops:	Pointer to the list of watchdog operations.

 * @bootstatus:	Status of the watchdog device at boot.
@@ -82,6 +84,7 @@ struct watchdog_device { 
	int id;

	struct device *dev;

	struct device *parent;

	const struct attribute_group **groups;

	const struct watchdog_info *info;

	const struct watchdog_ops *ops;

	unsigned int bootstatus;

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