Re: [PATCH 1/2] pinctrl: add function to parse generic pinconfigproperties from a dt node

From: Linus Walleij
Date: Sun Jun 16 2013 - 06:39:48 EST

On Fri, Jun 14, 2013 at 4:52 PM, Laurent Pinchart
<laurent.pinchart@xxxxxxxxxxxxxxxx> wrote:
> On Friday 14 June 2013 11:18:22 Heiko Stübner wrote:

>> > What's the expected way to disable pull-ups in DT ? Should it be
>> > 'bias-pull-up = <0>;' or 'bias-disable;' ?
>> According to the kernedoc I think both are valid and should be handled.
>> Using bias-disable is more descriptive but would also include disabling a
>> "high-impedance" or "bus-hold" bias (if supported by the hardware).
> OK. I still fail to see how the various bias options are supposed to interract
> together, but I don't think I'll get an answer on that.
>> Personally, for my rockchip stuff I go with using the
>> "bias-pull-pin-default" <-> "bias-disable".

I think bias-pull-up = <0>; should actually mean "connect the
pin to VDD" and bias-pull-down = <0>; should mean "ground
the pin".

This makes a lot of sense from the electronics side of things,
let's not create a terminology that appeals to programmers,
such that "zero always means boolean disable", because we're
dealing with electronics here.

Linus Walleij
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