Re: [RFC PATCH v2 2/3] of: Add support for -@ when compiling overlays

From: Florian Fainelli
Date: Wed Apr 27 2022 - 20:02:05 EST

On 4/27/2022 2:24 PM, Rob Herring wrote:
On Wed, Apr 27, 2022 at 02:52:42PM -0400, Detlev Casanova wrote:
This commit adds an option to compile all device trees with -@ to add the
symbol table to the Device Tree Blobs.

Why would we want to tie this to the kernel config?

Globally enabling it has already been discussed and rejected.

It prepares the introduction of device tree overlays that are
not applied on device trees at compile time (dtbo files.)

These device tree overlays will be used by either a bootloader or a
linux userspace tool to extend the base device tree.

This is used e.g. for drivers that need device tree nodes for optional
non plug and play devices, like an external DSI touchscreen panel that
embeds different i2c devices to control it.

You can already set DTC_FLAGS per directory (and target?), so enable it
for the dtbs that have overlays.

Looks like this patch series from Aurelien should take care of that: