[PATCH 2/2] at91sam9_wdt: Allow watchdog to reset device at early boot

[timo.kokkonen@offcode.fi (Timo Kokkonen)]

Hi,

On 18.02.2015 22:21, Boris Brezillon wrote:
> On Wed, 18 Feb 2015 09:50:02 -0800
> Guenter Roeck <linux@roeck-us.net> wrote:
>
>> On Wed, Feb 18, 2015 at 05:00:33PM +0100, Alexandre Belloni wrote:
>>> Hi,
>>>
>>> On 18/02/2015 at 06:50:44 -0800, Guenter Roeck wrote :
>>>>>>>    Optional properties:
>>>>>>>    - timeout-sec: Contains the watchdog timeout in seconds.
>>>>>>> +- early-timeout-sec: If present, specifies a timeout value in seconds
>>>>>>> +  that the driver keeps on ticking the watchdog HW on behalf of user
>>>>>>> +  space. Once this timeout expires watchdog is left to expire in
>>>>>>> +  timeout-sec seconds. If this propery is set to zero, watchdog is
>>>>>>> +  started (or left running) so that a reset occurs in timeout-sec
>>>>>>> +  since the watchdog was started.
>>>>>>>
>>>>>>>    Example:
>>>>>>>
>>>>>>>    watchdog {
>>>>>>>    	 timeout-sec = <60>;
>>>>>>> +	 early-timeout-sec = <120>;
>>>>>>
>>>>>> That is not a generic property as you defined it; if so,
>>>>>> it would have to be implemented in the watchdog core code,
>>>>>> not in the at91 code. You'll have to document it in the bindings
>>>>>> description for at91sam9_wdt.
>>>>>
>>>>> Then, if this is a controller specific property, it should be defined
>>>>> with the 'atmel,' prefix.
>>>>> We're kind of looping here: the initial discussion was "is there a need
>>>>> for this property to be a generic one ?", and now you're saying no,
>>>>> while you previously left the door opened.
>>>>>
>>>>> Tomi is proposing a generic approach, as you asked him to. I agree that
>>>>> parsing the property in core code and making its value part of the
>>>>> generic watchdog struct makes sense (that's what I proposed to Tomi a
>>>>> few weeks ago).
>>>>>
>>>> Hmm ... the problem here is that the property description creates the
>>>> assumption or expectation that the property is used if defined,
>>>> which is not the case.
>>>>
>>>> I am not sure how to best resolve this. Maybe a comment in the property
>>>> description stating that implementation of is device (driver) dependent ?
>>>> After all, that is true for the timeout-sec property as well.
>>>>
>>>
>>> I would leave it in the generic file and state that it may not be
>>> implemented in the driver. That way, the property is documented for new
>>> driver writers.
>>>
>> Yes, that would be fine ok me.
>
> Great!
> Timo can you change the documentation accordingly ?

Yes, sure. Will send v4 soon.

-Timo