path: root/Documentation/watchdog/watchdog-kernel-api.txt
diff options
Diffstat (limited to 'Documentation/watchdog/watchdog-kernel-api.txt')
1 files changed, 8 insertions, 5 deletions
diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt
index 4b93c28..227f6cd 100644
--- a/Documentation/watchdog/watchdog-kernel-api.txt
+++ b/Documentation/watchdog/watchdog-kernel-api.txt
@@ -1,6 +1,6 @@
The Linux WatchDog Timer Driver Core kernel API.
-Last reviewed: 29-Nov-2011
+Last reviewed: 16-Mar-2012
Wim Van Sebroeck <>
@@ -77,6 +77,7 @@ struct watchdog_ops {
int (*ping)(struct watchdog_device *);
unsigned int (*status)(struct watchdog_device *);
int (*set_timeout)(struct watchdog_device *, unsigned int);
+ unsigned int (*get_timeleft)(struct watchdog_device *);
long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long);
@@ -117,11 +118,13 @@ they are supported. These optional routines/operations are:
status of the device is reported with watchdog WDIOF_* status flags/bits.
* set_timeout: this routine checks and changes the timeout of the watchdog
timer device. It returns 0 on success, -EINVAL for "parameter out of range"
- and -EIO for "could not write value to the watchdog". On success the timeout
- value of the watchdog_device will be changed to the value that was just used
- to re-program the watchdog timer device.
+ and -EIO for "could not write value to the watchdog". On success this
+ routine should set the timeout value of the watchdog_device to the
+ achieved timeout value (which may be different from the requested one
+ because the watchdog does not necessarily has a 1 second resolution).
(Note: the WDIOF_SETTIMEOUT needs to be set in the options field of the
watchdog's info structure).
+* get_timeleft: this routines returns the time that's left before a reset.
* ioctl: if this routine is present then it will be called first before we do
our own internal ioctl call handling. This routine should return -ENOIOCTLCMD
if a command is not supported. The parameters that are passed to the ioctl
@@ -167,4 +170,4 @@ driver specific data to and a pointer to the data itself.
The watchdog_get_drvdata function allows you to retrieve driver specific data.
The argument of this function is the watchdog device where you want to retrieve
-data from. The function retruns the pointer to the driver specific data.
+data from. The function returns the pointer to the driver specific data.