watchdog: watchdog_core: Add watchdog registration deferral mechanism

Currently, watchdog subsystem require the misc subsystem to
register a watchdog. This may not be the case in case of an
early registration of a watchdog, which can be required when
the watchdog cannot be disabled.

This patch introduces a deferral mechanism to remove this requirement.

Signed-off-by: Jean-Baptiste Theou <jtheou@adeneo-embedded.us>
Reviewed-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/include/linux/watchdog.h b/include/linux/watchdog.h
index a746bf5216f8..f47feada5b42 100644
--- a/include/linux/watchdog.h
+++ b/include/linux/watchdog.h
@@ -65,6 +65,8 @@ struct watchdog_ops {
  * @driver-data:Pointer to the drivers private data.
  * @lock:       Lock for watchdog core internal use only.
  * @status:     Field that contains the devices internal status bits.
+ * @deferred: entry in wtd_deferred_reg_list which is used to
+ *                         register early initialized watchdogs.
  *
  * The watchdog_device structure contains all information about a
  * watchdog timer device.
@@ -95,6 +97,7 @@ struct watchdog_device {
 #define WDOG_ALLOW_RELEASE      2       /* Did we receive the magic char ? */
 #define WDOG_NO_WAY_OUT         3       /* Is 'nowayout' feature set ? */
 #define WDOG_UNREGISTERED       4       /* Has the device been unregistered */
+        struct list_head deferred;
 };
 
 #define WATCHDOG_NOWAYOUT               IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT)