Hi Oleksij,

On 06/11/2017 09:19 AM, Oleksij Rempel wrote:

Hi Rob,

On Fri, Jun 09, 2017 at 10:41:30AM -0500, Rob Herring wrote:

quoted

On Fri, Jun 9, 2017 at 9:16 AM, Oleksij Rempel [off-list ref] wrote:

quoted

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.

that's fine, but the proposed extension is supposedly not wanted.

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

It'd rather be better to fix the drivers and remove the properties
from these found device tree binding descriptions.

Please fixme if I miss something.

Why is GPIO hogging mechanism not good enough for your purpose?

--
With best wishes,
Vladimir