watchdog: Add support for minimum time between heartbeats

Some watchdogs require a minimum time between heartbeats.
Examples are the watchdogs in DA9062 and AT91SAM9x.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 3 insertions, 0 deletions

diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt
index 9eabca1d9355..917eeeabfa5e 100644
--- a/Documentation/watchdog/watchdog-kernel-api.txt
+++ b/Documentation/watchdog/watchdog-kernel-api.txt
@@ -52,6 +52,7 @@ struct watchdog_device {
         unsigned int timeout;
         unsigned int min_timeout;
         unsigned int max_timeout;
+        unsigned int min_hw_heartbeat_ms;
         unsigned int max_hw_heartbeat_ms;
         struct notifier_block reboot_nb;
         struct notifier_block restart_nb;
@@ -81,6 +82,8 @@ It contains following fields:
 * max_timeout: the watchdog timer's maximum timeout value (in seconds),
   as seen from userspace. If set, the maximum configurable value for
   'timeout'. Not used if max_hw_heartbeat_ms is non-zero.
+* min_hw_heartbeat_ms: Minimum time between heartbeats sent to the chip,
+  in milli-seconds.
 * max_hw_heartbeat_ms: Maximum hardware heartbeat, in milli-seconds.
   If set, the infrastructure will send heartbeats to the watchdog driver
   if 'timeout' is larger than max_hw_heartbeat_ms, unless WDOG_ACTIVE