[periperi] How to set default GPIO pin ?

[Linus Walleij]

On Wed, Sep 10, 2014 at 10:55 AM, Laurent Pinchart
<laurent.pinchart at ideasonboard.com> wrote:
> On Sunday 31 August 2014 22:08:52 Kuninori Morimoto wrote:
>>
>> I know we can use "defalt" PFC settings on DT.
>> But, how to use "defalt" GPIO pin settings on DT ?
>>
>> We would like to use GPIO 7-17 as Low output,
>> and do nothing after boot.
>
> From a DT point of view I believe this is supposed to be done by specifying
> the output-low or output-high properties in the pinctrl configuration node.
> However, these properties are not supported by the PFC driver, and there's no
> easy way for the PFC driver to configure GPIOs handled by a different driver
> such as the gpio-rcar driver for instance.
>
> Linus, do you have any hindsight on how this should be implemented ?

I have suggested adding GPIO hogs, so that a GPIO node can specify
that some GPIO's specified on the local ship be hogged high or
low at probe. Generic DT bindings and generic code in gpiolib.c.

gpios-hog-high = <....>;
gpios-hog-low = <....>;

Yours,
Linus Walleij