watchdog: documentation: describe nowayout in coversion-guide

nowayout is also handled by the watchdog core. Describe how this needs
to be addressed in the conversion guide.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 19 insertions, 0 deletions

diff --git a/Documentation/watchdog/convert_drivers_to_kernel_api.txt b/Documentation/watchdog/convert_drivers_to_kernel_api.txt
index ae1e90036d06..be8119bb15d2 100644
--- a/Documentation/watchdog/convert_drivers_to_kernel_api.txt
+++ b/Documentation/watchdog/convert_drivers_to_kernel_api.txt
@@ -163,6 +163,25 @@ Here is a simple example for a watchdog device:
 +};
 
 
+Handle the 'nowayout' feature
+-----------------------------
+
+A few drivers use nowayout statically, i.e. there is no module parameter for it
+and only CONFIG_WATCHDOG_NOWAYOUT determines if the feature is going to be
+used. This needs to be converted by initializing the status variable of the
+watchdog_device like this:
+
+        .status = WATCHDOG_NOWAYOUT_INIT_STATUS,
+
+Most drivers, however, also allow runtime configuration of nowayout, usually
+by adding a module parameter. The conversion for this would be something like:
+
+        watchdog_set_nowayout(&s3c2410_wdd, nowayout);
+
+The module parameter itself needs to stay, everything else related to nowayout
+can go, though. This will likely be some code in open(), close() or write().
+
+
 Register the watchdog device
 ----------------------------