Re: [PATCH 1/2] power: reset: Add QEMU virt-ctrl driver

From: Kuan-Wei Chiu

Date: Thu Jan 15 2026 - 10:21:45 EST


Hi Daniel,

On Thu, Jan 15, 2026 at 10:29:29PM +0900, Daniel Palmer wrote:
> Hi Kuan-Wei,
>
> On Thu, 15 Jan 2026 at 15:15, Kuan-Wei Chiu <visitorckw@xxxxxxxxx> wrote:
>
> > > FWIW: I have a driver for this in my "m68k with devicetree" tree. As
> > > far as I could tell the virt_ctrl thing in QEMU might get more
> > > features aside from power control.
> > > So I made it a misc device instead.
> >
> > Thanks for the note.
> > Just out of curious, are there currently specific plans to add
> > non-power features to virt_ctrl?
>
> The docs here suggest that power control is the only currently
> implemented feature but doesn't have to be the only feature:
> https://github.com/qemu/qemu/blob/master/docs/specs/virt-ctlr.rst
>
> > If new features are added, shouldn't they be exposed via separate
> > drivers in their respective subsystems, rather than consolidating
> > everything into a misc driver?
>
> I guess if it did get new features maybe it'd be a multifunction
> device? Since nothing except power control has ever actually been
> implemented, maybe the way you have it right now makes the most sense.
>
I agree that migrating to an MFD architecture would be the right move
if/when qemu implements additional features. For now, I will stick to
the current approach in drivers/power/reset as it fits the existing
functionality best.

Thanks again for your feedback.

Regards,
Kuan-Wei