Re: [PATCH V2 1/9] gpio: gpio-rockchip: parse gpio-ranges for bank id

Linus Walleij
2023-02-23T09:00:29Z

On Mon, Feb 13, 2023 at 11:28 PM Chris Morgan <macroalpha82@gmail.com> wrote:

> From: Chris Morgan <macromorgan@hotmail.com>
>
> Use the new devicetree property of gpio-ranges to determine the GPIO
> bank ID. Preserve the "old" way of doing things too, so that boards
> can be migrated and tested gradually (I only have a 3566 and 3326 to
> test).
>
> Signed-off-by: Chris Morgan <macromorgan@hotmail.com>

gpio-ranges are not supposed to be used like this, because there is
no semantic restrictions on how gpio-ranges are set up. For example:

gpio-ranges = <&pfc 0 0 32>;

that looks nice for this usecase, and I guess this is something
like what you have but then look at this from arch/arm/boot/dts/hi3620.dtsi:

gpio-ranges = < &pmx0 0 14 1 &pmx0 1 15 1 &pmx0 2 16 1
&pmx0 3 16 1 &pmx0 4 16 1 &pmx0 5 16 1
&pmx0 6 16 1 &pmx0 7 16 1>;

This is perfectly fine as well. Ranges can start anywhere in the hardware
offsets and go anywhere, and be set up in smaller chunks however
the author of the DTS file wants it.

I am pretty sure the same discontiguous
ranges can be encoded into the rk_gpio relevant DTS files as well,
so this is not a good solution to your problem.

What has been used in the past is just some unique hardware ID in the
device tree, so I would just add that.

Yours,
Linus Walleij