diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-watchdog | 9 | ||||
| -rw-r--r-- | drivers/watchdog/watchdog_dev.c | 21 |
2 files changed, 27 insertions, 3 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-watchdog b/Documentation/ABI/testing/sysfs-class-watchdog index 675f9b537661..9860a8b2ba75 100644 --- a/Documentation/ABI/testing/sysfs-class-watchdog +++ b/Documentation/ABI/testing/sysfs-class-watchdog @@ -17,8 +17,13 @@ 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'. + It is a read/write file. While reading, it gives '1' + if the device has the nowayout feature set, otherwise + it gives '0'. Writing a '1' to the file enables the + nowayout feature. Once set, the nowayout feature + cannot be disabled, so writing a '0' either has no + effect (if the feature was already disabled) or + results in a permission error. What: /sys/class/watchdog/watchdogn/state Date: August 2015 diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index 62483a99105c..4feecd14e9ab 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -452,7 +452,26 @@ static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr, return sprintf(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, &wdd->status)); } -static DEVICE_ATTR_RO(nowayout); + +static ssize_t nowayout_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len) +{ + struct watchdog_device *wdd = dev_get_drvdata(dev); + unsigned int value; + int ret; + + ret = kstrtouint(buf, 0, &value); + if (ret) + return ret; + if (value > 1) + return -EINVAL; + /* nowayout cannot be disabled once set */ + if (test_bit(WDOG_NO_WAY_OUT, &wdd->status) && !value) + return -EPERM; + watchdog_set_nowayout(wdd, value); + return len; +} +static DEVICE_ATTR_RW(nowayout); static ssize_t status_show(struct device *dev, struct device_attribute *attr, char *buf) |