watchdog: Add {min,max}_timeout sysfs nodes

The valid range for the 'timeout' value is useful information so expose
the min and max timeout values via sysfs.

Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210511062953.485252-1-juergh@canonical.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 2946f3a63110c6ceedf17bb80a799cee23422079..74070661d36875bd5b17fd465ad61df98c143e6c 100644 (file)
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -525,6 +525,24 @@ static ssize_t timeout_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(timeout);
 
+static ssize_t min_timeout_show(struct device *dev,
+                               struct device_attribute *attr, char *buf)
+{
+       struct watchdog_device *wdd = dev_get_drvdata(dev);
+
+       return sysfs_emit(buf, "%u\n", wdd->min_timeout);
+}
+static DEVICE_ATTR_RO(min_timeout);
+
+static ssize_t max_timeout_show(struct device *dev,
+                               struct device_attribute *attr, char *buf)
+{
+       struct watchdog_device *wdd = dev_get_drvdata(dev);
+
+       return sysfs_emit(buf, "%u\n", wdd->max_timeout);
+}
+static DEVICE_ATTR_RO(max_timeout);
+
 static ssize_t pretimeout_show(struct device *dev,
                               struct device_attribute *attr, char *buf)
 {
@@ -609,6 +627,8 @@ static struct attribute *wdt_attrs[] = {
        &dev_attr_state.attr,
        &dev_attr_identity.attr,
        &dev_attr_timeout.attr,
+       &dev_attr_min_timeout.attr,
+       &dev_attr_max_timeout.attr,
        &dev_attr_pretimeout.attr,
        &dev_attr_timeleft.attr,
        &dev_attr_bootstatus.attr,