Some watchdogs rewrite the timer on every ping, so they don't need a specific
set_timeout callback. Allow the callback to be empty for such devices.
Signed-off-by: Wolfram Sang <w.sang@xxxxxxxxxxxxxx>
---
.../watchdog/convert_drivers_to_kernel_api.txt | 10 ++++++----
Documentation/watchdog/watchdog-kernel-api.txt | 4 +++-
drivers/watchdog/watchdog_dev.c | 11 ++++++-----
3 files changed, 15 insertions(+), 10 deletions(-)
diff --git a/Documentation/watchdog/convert_drivers_to_kernel_api.txt b/Documentation/watchdog/convert_drivers_to_kernel_api.txt
index be8119b..25647a3 100644
--- a/Documentation/watchdog/convert_drivers_to_kernel_api.txt
+++ b/Documentation/watchdog/convert_drivers_to_kernel_api.txt
@@ -51,10 +51,12 @@ Here is a overview of the functions and probably needed actions:
set
WDIOC_SETTIMEOUT:
- Options in watchdog_info need to have WDIOF_SETTIMEOUT set
- and a set_timeout-callback has to be defined. The core will also
- do limit-checking, if min_timeout and max_timeout in the watchdog
- device are set. All is optional.
+ Options in watchdog_info need to have WDIOF_SETTIMEOUT set. The core
+ will also do limit-checking, if min_timeout and max_timeout in the
+ watchdog device are set. By default, the timeout variable of the
+ watchdog device will simply get updated. Additionally, a
+ set_timeout-callback can be defined if further actions are needed
+ (e.g. hardware setup, more advanced checks). All is optional.
WDIOC_GETTIMEOUT:
No preparations needed
diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt
index 4b93c28..dcf1cfe 100644
--- a/Documentation/watchdog/watchdog-kernel-api.txt
+++ b/Documentation/watchdog/watchdog-kernel-api.txt
@@ -121,7 +121,9 @@ they are supported. These optional routines/operations are:
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).
+ watchdog's info structure. If it is set, and no set_timeout function is
+ provided, only the update of the timeout value will happen. This is enough
+ if the ping of the watchdog will rewrite the timer anyway.)
* ioctl: if this routine is present then it will be called first before we do
our own internal ioctl call handling. This routine should return -ENOIOCTLCMD
if a command is not supported. The parameters that are passed to the ioctl
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 1199da0..ec224b4 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -215,17 +215,18 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd,
watchdog_ping(wdd);
return 0;
case WDIOC_SETTIMEOUT:
- if ((wdd->ops->set_timeout == NULL) ||
- !(wdd->info->options & WDIOF_SETTIMEOUT))
+ if (!(wdd->info->options & WDIOF_SETTIMEOUT))
return -EOPNOTSUPP;
if (get_user(val, p))
return -EFAULT;
if ((wdd->max_timeout != 0) &&
(val < wdd->min_timeout || val > wdd->max_timeout))
return -EINVAL;
- err = wdd->ops->set_timeout(wdd, val);
- if (err < 0)
- return err;
+ if (wdd->ops->set_timeout) {
+ 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
--
1.7.8.3
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