Re: [PATCH] regulator: gpio: Reword the binding document

[Marek Vasut <marek.vasut@gmail.com>]

On 2/19/19 11:10 AM, Harald Geyer wrote:
> Marek Vasut writes:
>> On 2/18/19 11:18 PM, Harald Geyer wrote:
>>> From the explanations provided by Mark it is clear that this property
>>> is an artifact of the implementation in linux. I think we should document
>>> is as such. How about:
>>>
>>> gpios-states : On operating systems, that don't support reading back gpio
>>> 	       values in output mode (most notably linux), this array
>>> 	       provides the state of GPIO pins set when requesting them
>>> 	       from the gpio controller.
>>
>> That's good.
>>
>>> Systems, that are capable of
>>> 	       preserving state when requesting the lines, are free to
>>> 	       ignore this property.
>>
>> Are they ?
> 
> I think so. Also this seems to be what Mark wrote yesterday:
> 
> | With the GPIO API as it stands it is unfortunately not possible to
> | preserve the state, if the API were fixed we'd preserve state.
> 
>> I think there are systems which depend on preconfiguring the
>> GPIO according to this property.
> 
> These systems need to preconfigure the GPIOs in firmware anyway, so
> they should be fine so long as the driver preserves state.
> 
> Since the original wording doesn't give any guarantees, I think the
> new wording doesn't change anything. It just makes it clearer, that
> there are no guarantees and that some drivers will happily overwrite
> state when this property is absent.

OK, so how can we move forward with this ? We discussed a lot, but I
don't know what we should do about the patch.

-- 
Best regards,
Marek Vasut