[PATCH v1 1/1] gpio: of: provide option generic property for initial line states

[Oleksij Rempel]

Hi Rob,

On Fri, Jun 09, 2017 at 10:41:30AM -0500, Rob Herring wrote:
> On Fri, Jun 9, 2017 at 9:16 AM, Oleksij Rempel <o.rempel at pengutronix.de> wrote:
> > This property is needed for barebox or may be other bootloaders
> > to set proper gpio configuration as early as possible.
> >
> > This example is mainly based on "lines-initial-states" property
> > from this binding documentation:
> > Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt
> 
> Don't we have a binding for this already based on gpio-hogs.

Markus Pargmann was working on this topic before and suddenly was not
able to finish it.
I found only some not finished discussions and no code or documentation
in linux kernel upstream.

So far, I was able to find fallowing patches and discussions:
patch 23.08.2015, last comment 11.05.2017:
https://patchwork.kernel.org/patch/7096721/

patch 23.02.2016, last comment 09.03.2016:
https://patchwork.ozlabs.org/patch/586743/

Since there was objections about node-like design for gpio-initval, I
provided an array property, which is similar to initval properties already used
for different other device nodes. For example:

Documentation/devicetree/bindings/net/wireless/qcom,ath10k.txt
qcom,ath10k-calibration-data

Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt
lines-initial-states

Please fixme if I miss something.

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