[RFC PATCH 2/2] arm: rockchip-rk3568-evb: apply dt overlay for evb7

[Trent Piepho]

On Tue, Jun 29, 2021 at 5:32 AM Michael Riesch
<michael.riesch at wolfvision.net> wrote:
> @@ -63,6 +64,9 @@ static int rk3568_evb_detect_version(void)
>                 evb_hw_id = 6;
>         } else {
>                 evb_hw_id = 7;
> +               setenv("global.of.overlay.dir", "boot");

Hardcoding the location of boot files in the rootfs into board code
doesn't seem right to me.

Seems like either creating a nv/global.of.overlay.dir file in the
default env for the board or creating an init script that sets that
variable would be the way to set this.

> +               setenv("global.of.overlay.filepattern",
> +                      "rk3568-evb7-overlay.dtb*");

What if one had a board magicvar, something like:

globalvar_add_simple("board.variant", "rk3568-evb7");  // Or just evb7
if rk3568 is already somewhere else
BAREBOX_MAGICVAR(global.board.variant, "The board variant");

Then an init script could easily construct the overlay:

env/init/board-overlay:
global of.overlay.filepattern="${global.of.overlay.filepattern}
${global.board.variant}-overlay.dtbo"

Since every overlay file is added to the same variable, some care
needs to be taken to ensure different initscripts work together.  Thus
the append in the above script.