Re: [PATCH 1/1] riscv: dts: Enable device-tree overlay support for starfive devices

[Walker Chen <walker.chen@starfivetech.com>]

On 2023/7/13 0:23, Conor Dooley wrote:
> On Wed, Jul 12, 2023 at 06:17:19PM +0200, Emil Renner Berthing wrote:
>> On Mon, 10 Jul 2023 at 20:29, Conor Dooley <conor@kernel.org> wrote:
>> >
>> >
>> > Emil, Walker,
>> >
>> > On Tue, Jun 27, 2023 at 04:06:20PM +0800, Felix Moessbauer wrote:
>> > > Add the '-@' DTC option for the starfive devices. This option
>> > > populates the '__symbols__' node that contains all the necessary symbols
>> > > for supporting device-tree overlays (for instance from the firmware or
>> > > the bootloader) on these devices.
>> > >
>> > > The starfive devices allow various modules to be connected and this
>> > > enables users to create out-of-tree device-tree overlays for these modules.
>> > >
>> > > Please note that this change does increase the size of the resulting DTB
>> > > by ~20%. For example, with v6.4 increase in size is as follows:
>> >
>> > Whatcha think?
>> 
>> I'm fine with it. I just wonder why it's only the Nvidia Tegra boards
>> and the VisionFive's that need this. Surely other boards have pins for
>> expansion cards.
> 
> It's totally not just these two - there's been a flurry of similar
> patches recently. The RPi stuff got it - I think I Acked that one from
> the DT side while Rob and Krzysztof were out of office, partially on the
> basis that the Nvidia stuff had it (and IIRC Renesas).
> Since then there's been a couple other ones that got the same treatment,
> including 32-bit ARM Microchip stuff. I've been avoiding doing it for the
> RISC-V Microchip to see if Rob decides that what I Acked was a problem.
> 
> It seems generally helpful, so I've been a little suspicious as to why
> it was not done already...

I agree to use DT overlay though this will increase a little bit size for DTB.
For users who want to use expansion card like audio daughter board, it provides a convenient way.

Best regards,
Walker