[PATCH V2] watchdog: Add watchdog device control through sysfs attributes
From: Pratyush Anand
Date: Mon Aug 31 2015 - 02:34:41 EST
This patch adds following attributes to watchdog device's sysfs interface.
* state - reads whether device is active or not
* identity - reads Watchdog device's identity string.
* timeout - reads current timeout.
* timeleft - reads timeleft before watchdog generates a reset
* bootstatus - reads status of the watchdog device at boot
* status - reads watchdog device's internal status bits
* nowayout - reads whether nowayout feature was set or not
Testing with iTCO_wdt:
# cd /sys/class/watchdog/watchdog1/
# ls
bootstatus dev device identity nowayout power state
subsystem timeleft timeout uevent
# cat identity
iTCO_wdt
# cat timeout
30
# cat state
inactive
# echo > /dev/watchdog1
# cat timeleft
26
# cat state
active
# cat bootstatus
0
# cat nowayout
0
Signed-off-by: Pratyush Anand <panand@xxxxxxxxxx>
---
Changes since V1(RFC):
* Removed keepalive and start ABI
* timeout is read only now
* state returns text
* only supported ABI visible
* ABI contact changed to MAINTAINER
* unnecessary mutex removed
* aligned continuation with '('
* unnecessary initialization of status (= 0) corrected
* unnecessary else removed
* used __ATTRIBUTE_GROUPS
* removed watchdog_device_create and added functionality in
watchdog_dev_register.
* optimized nowayout_show
* Now no -EOPNOTSUPP return for timeout read in case of wdd->timeout = 0.
Documentation/ABI/testing/sysfs-class-watchdog | 51 ++++++++++
drivers/watchdog/watchdog_core.c | 16 +--
drivers/watchdog/watchdog_core.h | 3 +-
drivers/watchdog/watchdog_dev.c | 132 ++++++++++++++++++++++++-
4 files changed, 183 insertions(+), 19 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-class-watchdog
diff --git a/Documentation/ABI/testing/sysfs-class-watchdog b/Documentation/ABI/testing/sysfs-class-watchdog
new file mode 100644
index 000000000000..736046b33040
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-watchdog
@@ -0,0 +1,51 @@
+What: /sys/class/watchdog/watchdogn/bootstatus
+Date: August 2015
+Contact: Wim Van Sebroeck <wim@xxxxxxxxx>
+Description:
+ It is a read only file. It contains status of the watchdog
+ device at boot. It is equivalent to WDIOC_GETBOOTSTATUS of
+ ioctl interface.
+
+What: /sys/class/watchdog/watchdogn/identity
+Date: August 2015
+Contact: Wim Van Sebroeck <wim@xxxxxxxxx>
+Description:
+ It is a read only file. It contains identity string of
+ watchdog device.
+
+What: /sys/class/watchdog/watchdogn/nowayout
+Date: August 2015
+Contact: Wim Van Sebroeck <wim@xxxxxxxxx>
+Description:
+ It is a read only file. While reading, it gives '1' if that
+ device supports nowayout feature else, it gives '0'.
+
+What: /sys/class/watchdog/watchdogn/state
+Date: August 2015
+Contact: Wim Van Sebroeck <wim@xxxxxxxxx>
+Description:
+ It is a read only file. It gives active/inactive status of
+ watchdog device.
+
+What: /sys/class/watchdog/watchdogn/status
+Date: August 2015
+Contact: Wim Van Sebroeck <wim@xxxxxxxxx>
+Description:
+ It is a read only file. It contains watchdog device's
+ internal status bits. It is equivalent to WDIOC_GETSTATUS
+ of ioctl interface.
+
+What: /sys/class/watchdog/watchdogn/timeleft
+Date: August 2015
+Contact: Wim Van Sebroeck <wim@xxxxxxxxx>
+Description:
+ It is a read only file. It contains value of time left for
+ reset generation. It is equivalent to WDIOC_GETTIMELEFT of
+ ioctl interface.
+
+What: /sys/class/watchdog/watchdogn/timeout
+Date: August 2015
+Contact: Wim Van Sebroeck <wim@xxxxxxxxx>
+Description:
+ It is a read only file. It is read to know about current
+ value of timeout programmed.
diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index 1a8059455413..3f9eb13b2023 100644
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -139,7 +139,7 @@ EXPORT_SYMBOL_GPL(watchdog_init_timeout);
static int __watchdog_register_device(struct watchdog_device *wdd)
{
- int ret, id, devno;
+ int ret, id;
if (wdd == NULL || wdd->info == NULL || wdd->ops == NULL)
return -EINVAL;
@@ -162,7 +162,7 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
return id;
wdd->id = id;
- ret = watchdog_dev_register(wdd);
+ ret = watchdog_dev_register(wdd, watchdog_class);
if (ret) {
ida_simple_remove(&watchdog_ida, id);
if (!(id == 0 && ret == -EBUSY))
@@ -174,23 +174,13 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
return id;
wdd->id = id;
- ret = watchdog_dev_register(wdd);
+ ret = watchdog_dev_register(wdd, watchdog_class);
if (ret) {
ida_simple_remove(&watchdog_ida, id);
return ret;
}
}
- devno = wdd->cdev.dev;
- wdd->dev = device_create(watchdog_class, wdd->parent, devno,
- NULL, "watchdog%d", wdd->id);
- if (IS_ERR(wdd->dev)) {
- watchdog_dev_unregister(wdd);
- ida_simple_remove(&watchdog_ida, id);
- ret = PTR_ERR(wdd->dev);
- return ret;
- }
-
return 0;
}
diff --git a/drivers/watchdog/watchdog_core.h b/drivers/watchdog/watchdog_core.h
index 6c951418fca7..38a9a2c6e7a2 100644
--- a/drivers/watchdog/watchdog_core.h
+++ b/drivers/watchdog/watchdog_core.h
@@ -31,7 +31,8 @@
/*
* Functions/procedures to be called by the core
*/
-extern int watchdog_dev_register(struct watchdog_device *);
+extern int watchdog_dev_register(struct watchdog_device *,
+ struct class *);
extern int watchdog_dev_unregister(struct watchdog_device *);
extern int __init watchdog_dev_init(void);
extern void __exit watchdog_dev_exit(void);
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 6aaefbad303e..4bbf022534c1 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -248,6 +248,115 @@ out_timeleft:
return err;
}
+static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct watchdog_device *wdd = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, &wdd->status));
+}
+static DEVICE_ATTR_RO(nowayout);
+
+static ssize_t status_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct watchdog_device *wdd = dev_get_drvdata(dev);
+ ssize_t status;
+ unsigned int val;
+
+ status = watchdog_get_status(wdd, &val);
+ if (!status)
+ status = sprintf(buf, "%u\n", val);
+
+ return status;
+}
+static DEVICE_ATTR_RO(status);
+
+static ssize_t bootstatus_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct watchdog_device *wdd = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%u\n", wdd->bootstatus);
+}
+static DEVICE_ATTR_RO(bootstatus);
+
+static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct watchdog_device *wdd = dev_get_drvdata(dev);
+ ssize_t status;
+ unsigned int val;
+
+ status = watchdog_get_timeleft(wdd, &val);
+ if (!status)
+ status = sprintf(buf, "%u\n", val);
+
+ return status;
+}
+static DEVICE_ATTR_RO(timeleft);
+
+static ssize_t timeout_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct watchdog_device *wdd = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%u\n", wdd->timeout);
+}
+static DEVICE_ATTR_RO(timeout);
+
+static ssize_t identity_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct watchdog_device *wdd = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%s\n", wdd->info->identity);
+}
+static DEVICE_ATTR_RO(identity);
+
+static ssize_t state_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct watchdog_device *wdd = dev_get_drvdata(dev);
+
+ if (watchdog_active(wdd))
+ return sprintf(buf, "active\n");
+
+ return sprintf(buf, "inactive\n");
+}
+static DEVICE_ATTR_RO(state);
+
+static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr,
+ int n)
+{
+ struct device *dev = container_of(kobj, struct device, kobj);
+ struct watchdog_device *wdd = dev_get_drvdata(dev);
+ umode_t mode = attr->mode;
+
+ if (attr == &dev_attr_status.attr && !wdd->ops->status)
+ mode = 0;
+ else if (attr == &dev_attr_timeleft.attr && !wdd->ops->get_timeleft)
+ mode = 0;
+
+ return mode;
+}
+static struct attribute *wdt_attrs[] = {
+ &dev_attr_state.attr,
+ &dev_attr_identity.attr,
+ &dev_attr_timeout.attr,
+ &dev_attr_timeleft.attr,
+ &dev_attr_bootstatus.attr,
+ &dev_attr_status.attr,
+ &dev_attr_nowayout.attr,
+ NULL,
+};
+
+static const struct attribute_group wdt_group = {
+ .attrs = wdt_attrs,
+ .is_visible = wdt_is_visible,
+};
+__ATTRIBUTE_GROUPS(wdt);
+
/*
* watchdog_ioctl_op: call the watchdog drivers ioctl op if defined
* @wddev: the watchdog device to do the ioctl on
@@ -514,13 +623,15 @@ static struct miscdevice watchdog_miscdev = {
/*
* watchdog_dev_register: register a watchdog device
* @watchdog: watchdog device
+ * @watchdog_class: watchdog class with which created device is associated
*
* Register a watchdog device including handling the legacy
* /dev/watchdog node. /dev/watchdog is actually a miscdevice and
* thus we set it up like that.
*/
-int watchdog_dev_register(struct watchdog_device *watchdog)
+int watchdog_dev_register(struct watchdog_device *watchdog,
+ struct class *watchdog_class)
{
int err, devno;
@@ -549,11 +660,22 @@ int watchdog_dev_register(struct watchdog_device *watchdog)
if (err) {
pr_err("watchdog%d unable to add device %d:%d\n",
watchdog->id, MAJOR(watchdog_devt), watchdog->id);
- if (watchdog->id == 0) {
- misc_deregister(&watchdog_miscdev);
- old_wdd = NULL;
- }
+ } else {
+ watchdog->dev = device_create_with_groups(watchdog_class,
+ watchdog->parent,
+ watchdog->cdev.dev,
+ watchdog, wdt_groups,
+ "watchdog%d",
+ watchdog->id);
+ if (IS_ERR(watchdog->dev))
+ err = PTR_ERR(watchdog->dev);
+ }
+
+ if (err && watchdog->id == 0) {
+ misc_deregister(&watchdog_miscdev);
+ old_wdd = NULL;
}
+
return err;
}
--
2.4.3
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