[PATCH v2 5/9] document: devicetree: bind pinconf with pin-single

[haojian.zhuang@gmail.com (Haojian Zhuang)]

On Wed, Oct 31, 2012 at 11:26 PM, Stephen Warren <swarren@wwwdotorg.org> wrote:
> On 10/31/2012 10:58 AM, Haojian Zhuang wrote:
>> On Tue, Oct 23, 2012 at 6:44 AM, Stephen Warren <swarren@wwwdotorg.org> wrote:
>>> 3) Why is pinctrl-single,gpio-func optional? Presumably you always need
>>> to program the pinmux HW to select the GPIO function. Yet, the driver
>>> code in an earlier patch seems to deliberately do nothing if this
>>> property is missing. Shouldn't the DT parsing return an error instead?
>>>
>> pinctrl-single,gpio-func is optional for above reason.
>
> Presumably the node that contains the pinctrl-single,gpio-func property
> is optional, but once you have such a node, pinctrl-single,gpio-func is
> required?
>
Yes, gpio-func is must required if the phandle of gpio range is defined.
I'll add such comments in document.

>>> I suppose it's OK that a generic pin controller binding would use the
>>> generic pin configuration config options. I'm still not convinced that
>>> the semantics of generic pin control make sense. Maybe if they're just
>>> arbitrary names for SoC-specific things it's fine though.
>>>
>>> Do these patches expose /all/ generic pin configuration options? It
>>> doesn't seem worth exposing only some of them and ignoring others.
>>
>> I believe general pinconf can't support all cases in different silicons.
>
> I tend to agree.
>
>> And we still have some common features that could be covered in general
>> pinconf. So we need a structure to support both pinconf & specific pinconf.
>
> But that tends to imply that adding support for generic pinconf into the
> pinctrl-simple driver isnt' actually going to be useful for anyone. If
> pinctrl-single only supports some part of your HW, how can you use it?
> Or, do you intend to somehow make pinctrl-single support both the common
> generic pinconf stuff, and somehow be extensible to support any
> SoC-specific pin config fields?

I'm intend to make pinctrl-single to support both the common generic pinconf
stuff and any SoC-specific pinconf. I'll try to handle it. But they
won't be included
in V3.