3 files changed, 34 insertions, 0 deletions

diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt
index 429f81bf0cf7..acdee39fb08a 100644
--- a/Documentation/watchdog/watchdog-kernel-api.txt
+++ b/Documentation/watchdog/watchdog-kernel-api.txt
@@ -42,6 +42,7 @@ struct watchdog_device {
         const struct watchdog_info *info;
         const struct watchdog_ops *ops;
         unsigned int bootstatus;
+        unsigned int timeout;
         void *driver_data;
         unsigned long status;
 };
@@ -50,6 +51,7 @@ It contains following fields:
 * info: a pointer to a watchdog_info structure. This structure gives some
   additional information about the watchdog timer itself. (Like it's unique name)
 * ops: a pointer to the list of watchdog operations that the watchdog supports.
+* timeout: the watchdog timer's timeout value (in seconds).
 * bootstatus: status of the device after booting (reported with watchdog
   WDIOF_* status bits).
 * driver_data: a pointer to the drivers private data of a watchdog device.
@@ -70,6 +72,7 @@ struct watchdog_ops {
         /* optional operations */
         int (*ping)(struct watchdog_device *);
         unsigned int (*status)(struct watchdog_device *);
+        int (*set_timeout)(struct watchdog_device *, unsigned int);
 };
 
 It is important that you first define the module owner of the watchdog timer
@@ -107,6 +110,13 @@ they are supported. These optional routines/operations are:
   info structure).
 * status: this routine checks the status of the watchdog timer device. The
   status of the device is reported with watchdog WDIOF_* status flags/bits.
+* set_timeout: this routine checks and changes the timeout of the watchdog
+  timer device. It returns 0 on success, -EINVAL for "parameter out of range"
+  and -EIO for "could not write value to the watchdog". On success the timeout
+  value of the watchdog_device will be changed to the value that was just used
+  to re-program the watchdog timer device.
+  (Note: the WDIOF_SETTIMEOUT needs to be set in the options field of the
+  watchdog's info structure).
 
 The status bits should (preferably) be set with the set_bit and clear_bit alike
 bit-operations. The status bits that are defined are:
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 9f5550e16ab5..2c0289deaadd 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -190,6 +190,26 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd,
                         return -EOPNOTSUPP;
                 watchdog_ping(wdd);
                 return 0;
+        case WDIOC_SETTIMEOUT:
+                if ((wdd->ops->set_timeout == NULL) ||
+                    !(wdd->info->options & WDIOF_SETTIMEOUT))
+                        return -EOPNOTSUPP;
+                if (get_user(val, p))
+                        return -EFAULT;
+                err = wdd->ops->set_timeout(wdd, val);
+                if (err < 0)
+                        return err;
+                wdd->timeout = val;
+                /* If the watchdog is active then we send a keepalive ping
+                 * to make sure that the watchdog keep's running (and if
+                 * possible that it takes the new timeout) */
+                watchdog_ping(wdd);
+                /* Fall */
+        case WDIOC_GETTIMEOUT:
+                /* timeout == 0 means that we don't know the timeout */
+                if (wdd->timeout == 0)
+                        return -EOPNOTSUPP;
+                return put_user(wdd->timeout, p);
         default:
                 return -ENOTTY;
         }
diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h
index db46fe89563e..9f33efe199d1 100644
--- a/include/linux/watchdog.h
+++ b/include/linux/watchdog.h
@@ -69,6 +69,7 @@ struct watchdog_device;
  * @stop:       The routine for stopping the watchdog device.
  * @ping:       The routine that sends a keepalive ping to the watchdog device.
  * @status:     The routine that shows the status of the watchdog device.
+ * @set_timeout:The routine for setting the watchdog devices timeout value.
  *
  * The watchdog_ops structure contains a list of low-level operations
  * that control a watchdog device. It also contains the module that owns
@@ -83,6 +84,7 @@ struct watchdog_ops {
         /* optional operations */
         int (*ping)(struct watchdog_device *);
         unsigned int (*status)(struct watchdog_device *);
+        int (*set_timeout)(struct watchdog_device *, unsigned int);
 };
 
 /** struct watchdog_device - The structure that defines a watchdog device
@@ -90,6 +92,7 @@ struct watchdog_ops {
  * @info:       Pointer to a watchdog_info structure.
  * @ops:        Pointer to the list of watchdog operations.
  * @bootstatus: Status of the watchdog device at boot.
+ * @timeout:    The watchdog devices timeout value.
  * @driver-data:Pointer to the drivers private data.
  * @status:     Field that contains the devices internal status bits.
  *
@@ -103,6 +106,7 @@ struct watchdog_device {
         const struct watchdog_info *info;
         const struct watchdog_ops *ops;
         unsigned int bootstatus;
+        unsigned int timeout;
         void *driver_data;
         unsigned long status;
 /* Bit numbers for status flags */