watchdog: Report firmware_version in sysfs

This synchronizes the information reported by ioctl and sysfs.
The mismatch is confusing because "wdctl" from util-linux uses the ioctl
when used with root privileges and sysfs without.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>

---

Userspace implementation:

https://github.com/util-linux/util-linux/pull/1927
---
 drivers/watchdog/watchdog_dev.c | 10 ++++++++++
 1 file changed, 10 insertions(+)


base-commit: 0b1dcc2cf55ae6523c6fbd0d741b3ac28c9f4536

On 2022-11-25 16:37-0800, Guenter Roeck wrote:
> On 11/25/22 14:23, Thomas Weißschuh wrote:
>> This synchronizes the information reported by ioctl and sysfs.
>> The mismatch is confusing because "wdctl" from util-linux uses the ioctl
>> when used with root privileges and sysfs without.
>> 
>> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
>> 
>> ---
>> 
>> Userspace implementation:
>> 
>> https://github.com/util-linux/util-linux/pull/1927
>> ---
>>   drivers/watchdog/watchdog_dev.c | 10 ++++++++++
>>   1 file changed, 10 insertions(+)
>> 
>> diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
>> index 55574ed42504..88c76e27873c 100644
>> --- a/drivers/watchdog/watchdog_dev.c
>> +++ b/drivers/watchdog/watchdog_dev.c
>> @@ -555,6 +555,15 @@ static ssize_t identity_show(struct device *dev, struct device_attribute *attr,
>>   }
>>   static DEVICE_ATTR_RO(identity);
>> +static ssize_t firmware_version_show(struct device *dev, struct device_attribute *attr,
>> +				     char *buf)
>> +{
>> +	struct watchdog_device *wdd = dev_get_drvdata(dev);
>> +
>> +	return sysfs_emit(buf, "%d\n", wdd->info->firmware_version);
>> +}
>> +static DEVICE_ATTR_RO(firmware_version);
>> +
>>   static ssize_t state_show(struct device *dev, struct device_attribute *attr,
>>   				char *buf)
>>   {
>> @@ -618,6 +627,7 @@ static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr,
>>   static struct attribute *wdt_attrs[] = {
>>   	&dev_attr_state.attr,
>>   	&dev_attr_identity.attr,
>> +	&dev_attr_firmware_version.attr,
>>   	&dev_attr_timeout.attr,
>>   	&dev_attr_min_timeout.attr,
>>   	&dev_attr_max_timeout.attr,
>> 
>> base-commit: 0b1dcc2cf55ae6523c6fbd0d741b3ac28c9f4536
> 
> I think this conflicts with drivers/watchdog/ziirave_wdt.c which generates its own
> firmnware_version attribute.

Indeed, thanks for the catch.

We probably can't change the attribute from ziirave_wdt, which is a bit
unfortunate as "firmware_version" would nicely match the name from
"struct watchdog_info".

How about "fw_version"?

That would match the naming of sysfs attributes from a bunch of other
subsystems.

And obviously an addition to Documentation/ABI/testing/sysfs-class-watchdog is
also missing from the patch.
I'll add it in v2.

Thomas

On 2022-11-25 17:46-0800, Guenter Roeck wrote:
> On 11/25/22 17:00, Thomas Weißschuh wrote:
>> On 2022-11-25 16:37-0800, Guenter Roeck wrote:
>>> On 11/25/22 14:23, Thomas Weißschuh wrote:
>>>> This synchronizes the information reported by ioctl and sysfs.
>>>> The mismatch is confusing because "wdctl" from util-linux uses the ioctl
>>>> when used with root privileges and sysfs without.
>>>> 
>>>> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
>>>> 
>>>> ---
>>>> 
>>>> Userspace implementation:
>>>> 
>>>> https://github.com/util-linux/util-linux/pull/1927
>>>> ---
>>>>    drivers/watchdog/watchdog_dev.c | 10 ++++++++++
>>>>    1 file changed, 10 insertions(+)
>>>> 
>>>> diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
>>>> index 55574ed42504..88c76e27873c 100644
>>>> --- a/drivers/watchdog/watchdog_dev.c
>>>> +++ b/drivers/watchdog/watchdog_dev.c
>>>> @@ -555,6 +555,15 @@ static ssize_t identity_show(struct device *dev, struct device_attribute *attr,
>>>>    }
>>>>    static DEVICE_ATTR_RO(identity);
>>>> +static ssize_t firmware_version_show(struct device *dev, struct device_attribute *attr,
>>>> +				     char *buf)
>>>> +{
>>>> +	struct watchdog_device *wdd = dev_get_drvdata(dev);
>>>> +
>>>> +	return sysfs_emit(buf, "%d\n", wdd->info->firmware_version);
>>>> +}
>>>> +static DEVICE_ATTR_RO(firmware_version);
>>>> +
>>>>    static ssize_t state_show(struct device *dev, struct device_attribute *attr,
>>>>    				char *buf)
>>>>    {
>>>> @@ -618,6 +627,7 @@ static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr,
>>>>    static struct attribute *wdt_attrs[] = {
>>>>    	&dev_attr_state.attr,
>>>>    	&dev_attr_identity.attr,
>>>> +	&dev_attr_firmware_version.attr,
>>>>    	&dev_attr_timeout.attr,
>>>>    	&dev_attr_min_timeout.attr,
>>>>    	&dev_attr_max_timeout.attr,
>>>> 
>>>> base-commit: 0b1dcc2cf55ae6523c6fbd0d741b3ac28c9f4536
>>> 
>>> I think this conflicts with drivers/watchdog/ziirave_wdt.c which generates its own
>>> firmnware_version attribute.
>> 
>> Indeed, thanks for the catch.
>> 
>> We probably can't change the attribute from ziirave_wdt, which is a bit
>> unfortunate as "firmware_version" would nicely match the name from
>> "struct watchdog_info".
>> 
>> How about "fw_version"?
>> 
> 
> I don't have a better idea. Go for it.

Will do.

>> That would match the naming of sysfs attributes from a bunch of other
>> subsystems.
>> 
>> And obviously an addition to Documentation/ABI/testing/sysfs-class-watchdog is
>> also missing from the patch.
>> I'll add it in v2.

Can I put you or Wim as contact into the docs?

It feels weird to have a random drive-by contributor listed there.

Thomas