Re: [PATCH 2/2] Make non-linear GPIO ranges accesible from gpiolib

From: Linus Walleij
Date: Tue Jun 25 2013 - 11:53:50 EST


On Tue, Jun 25, 2013 at 5:39 PM, Stephen Warren <swarren@xxxxxxxxxxxxx> wrote:
> On 06/25/2013 09:28 AM, Linus Walleij wrote:

>> But I do seem to recall some endless discussions about this,
>> I think we need to agree to disagree.
>
> But the whole point of a subsystem is to provide clear common semantics
> across all the different drivers that comprise it.

I guess we simply disagree on how deeply these semantics
should go.

> IMHO, it's a great
> failing of pinctrl that it doesn't clearly define its data model at all,
> and just leaves individual driver authors to use groups in whatever
> random fashion they want.

I do not think any driver is using it in a "random" fashion.
I would agree if the authors just stuck any pins into some
random groups named after colors or rock bands.

Obviously there is a mental model of the uses somewhere
behind the code.

> We really should have different entries in the
> pinctrl data model for these different concepts (real HW groups, and
> logical/virtual/SW groups) since they're entirely different things with
> different semantics.

That's what the tongue-in-cheek patch tried to convey, in some
kind of humorous manner. I was just trying to lighten up the
discussion a bit.

> Perhaps it's simplest if I just step out of pinctrl and let it exist as
> it is.

No not at all. Your work on defining and reviewing the pinctrl
drivers and DT bindings is much appreciated. However all
comittee work tend to lead to a few compromises. I don't
think this one compromise is especially hard to live with.

Yours,
Linus Walleij
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