Merge tag 'kvmarm-fixes-5.9-3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmar...

[platform/kernel/linux-starfive.git] / Documentation / watchdog / watchdog-kernel-api.rst

diff --git a/Documentation/watchdog/watchdog-kernel-api.rst b/Documentation/watchdog/watchdog-kernel-api.rst
index 068a55e..baf44e9 100644 (file)
--- a/Documentation/watchdog/watchdog-kernel-api.rst
+++ b/Documentation/watchdog/watchdog-kernel-api.rst
@@ -336,3 +336,15 @@ an action is taken by a preconfigured pretimeout governor preassigned to
 the watchdog device. If watchdog pretimeout governor framework is not
 enabled, watchdog_notify_pretimeout() prints a notification message to
 the kernel log buffer.
+
+To set the last known HW keepalive time for a watchdog, the following function
+should be used::
+
+  int watchdog_set_last_hw_keepalive(struct watchdog_device *wdd,
+                                     unsigned int last_ping_ms)
+
+This function must be called immediately after watchdog registration. It
+sets the last known hardware heartbeat to have happened last_ping_ms before
+current time. Calling this is only needed if the watchdog is already running
+when probe is called, and the watchdog can only be pinged after the
+min_hw_heartbeat_ms time has passed from the last ping.