watchdog: WatchDog Timer Driver Core - Add WDIOC_SETOPTIONS ioctl

This part add's the WDIOC_SETOPTIONS ioctl functionality
to the WatchDog Timer Driver Core framework.

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>

diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt
index abbcf2c..429f81b 100644
--- a/Documentation/watchdog/watchdog-kernel-api.txt
+++ b/Documentation/watchdog/watchdog-kernel-api.txt
@@ -56,8 +56,9 @@
   This data should only be accessed via the watchdog_set_drvadata and
   watchdog_get_drvdata routines.
 * status: this field contains a number of status bits that give extra
-  information about the status of the device (Like: is the device opened via
-  the /dev/watchdog interface or not, ...).
+  information about the status of the device (Like: is the watchdog timer
+  running/active, is the device opened via the /dev/watchdog interface or not,
+  ...).
 
 The list of watchdog operations is defined as:
 
@@ -109,6 +110,10 @@
 
 The status bits should (preferably) be set with the set_bit and clear_bit alike
 bit-operations. The status bits that are defined are:
+* WDOG_ACTIVE: this status bit indicates whether or not a watchdog timer device
+  is active or not. When the watchdog is active after booting, then you should
+  set this status bit (Note: when you register the watchdog timer device with
+  this bit set, then opening /dev/watchdog will skip the start operation)
 * WDOG_DEV_OPEN: this status bit shows whether or not the watchdog device
   was opened via /dev/watchdog.
   (This bit should only be used by the WatchDog Timer Driver Core).