watchdog: Read device status through sysfs attributes

This patch adds following attributes to watchdog device's sysfs interface
to read its different status.

* 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@redhat.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/Documentation/ABI/testing/sysfs-class-watchdog b/Documentation/ABI/testing/sysfs-class-watchdog
new file mode 100644 (file)
index 0000000..736046b
--- /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@iguana.be>
+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@iguana.be>
+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@iguana.be>
+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@iguana.be>
+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@iguana.be>
+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@iguana.be>
+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@iguana.be>
+Description:
+               It is a read only file. It is read to know about current
+               value of timeout programmed.

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 1c427beffadd97b3e95522fc9236193006d58fcc..71e47dde7d4afef081ece8ca6d2b321948d645b2 100644 (file)
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -46,6 +46,13 @@ config WATCHDOG_NOWAYOUT
          get killed. If you say Y here, the watchdog cannot be stopped once
          it has been started.
 
+config WATCHDOG_SYSFS
+       bool "Read different watchdog information through sysfs"
+       default n
+       help
+         Say Y here if you want to enable watchdog device status read through
+         sysfs attributes.
+
 #
 # General Watchdog drivers
 #

diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index 357d23c7954545caa345731b69a084979ab6ae05..551af042867c4f59e7860d35a3c4ca53e4ec95bc 100644 (file)
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -249,7 +249,7 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
 
        devno = wdd->cdev.dev;
        wdd->dev = device_create(watchdog_class, wdd->parent, devno,
-                                       NULL, "watchdog%d", wdd->id);
+                                       wdd, "watchdog%d", wdd->id);
        if (IS_ERR(wdd->dev)) {
                watchdog_dev_unregister(wdd);
                ida_simple_remove(&watchdog_ida, id);

diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 055a4e1b4c136fce4a613ac9bd53f6e212aa2691..f06fbcf0bea248381565b8d62341632afbd7f835 100644 (file)
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -247,6 +247,119 @@ out_timeleft:
        return err;
 }
 
+#ifdef CONFIG_WATCHDOG_SYSFS
+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);
+#else
+#define wdt_groups     NULL
+#endif
+
 /*
  *     watchdog_ioctl_op: call the watchdog drivers ioctl op if defined
  *     @wdd: the watchdog device to do the ioctl on
@@ -584,6 +697,7 @@ int watchdog_dev_unregister(struct watchdog_device *wdd)
 static struct class watchdog_class = {
        .name =         "watchdog",
        .owner =        THIS_MODULE,
+       .dev_groups =   wdt_groups,
 };
 
 /*