Re: Pinctrl DT for msm8998

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Wed, Apr 24, 2019 at 5:19 PM Marc Gonzalez <marc.w.gonzalez@xxxxxxx> wrote:

> +       i2c5_default: i2c5_default {
> +               pins = "gpio87", "gpio88";
> +               function = "blsp_i2c5";
> +               drive-strength = <2>;
> +               bias-disable;
> +       };
> +
> +       i2c5_sleep: i2c5_sleep {
> +               pins = "gpio87", "gpio88";
> +               function = "blsp_i2c5";
> +               drive-strength = <2>;
> +               bias-disable;
> +       };
>  };
>
> Note that the two nodes are identical. Do I still need both then?

Sometimes! If the hardware lose its state between suspend and
resume, having two different states will make the first state (default)
reload when you come back from sleep if the driver selects
"default" on its resume() path.

If it was in "default" when it went to sleep the pin control subsystem
will assume it is still in "default" when it comes back up.

Unless you use PIN_CONFIG_PERSIST_STATE I think, but I
forgot the details on how that works (use grep :)

Yours,
Linus Walleij