Re: [PATCH v5 06/13] mmc: arm_pl180: Power down card supplies at OS handoff

On Mon, Aug 24, 2026 at 10:01:15PM +0200, Linus Walleij wrote:
> On Mon, Aug 24, 2026 at 3:30 PM Stephan Gerhold
> <[email protected]> wrote:
> > On Sun, Aug 23, 2026 at 10:39:25PM +0200, Linus Walleij wrote:
> 
> > > PL180 card supplies remain enabled after probing and while U-Boot is
> > > running. They are no longer needed once control is handed to the operating
> > > system.
> > >
> > > Mark the driver for removal during OS preparation and disable its VMMC and
> > > VQMMC supplies from the remove callback.
> > >
> > > Signed-off-by: Linus Walleij <[email protected]>
> >
> > Is it worth briefly toggling the regulator off before Linux turns it on
> > again? Linux will typically need to turn them on again later during
> > boot, and even if not Linux should be able to deal with unused
> > regulators. I'm not sure it's worth adding such cleanup to U-Boot.
> 
> For our specific Ux500 target it is true.
> 
> But this driver is used by a bunch of platforms including some
> ARM reference designs, and also booting other operating systems
> than Linux.
> 
> Something could EFI boot off one SD card, then have rootfs
> on another one and the original boot card undefined in the
> hardware description for example. Albeit that sounds a bit
> stupid.
> 
> So I thought it'd be more clean to shut off the light on your way
> out.
> 
> But it's not like I'm married to the patch.
> 

I don't really have a strong opinion either. We can just leave it up to
the maintainers.

Can you re-run get_maintainer.pl on this series for v6? Seems like the
U-Boot MMC maintainers aren't included in this patch. I think it would
also be worth Ccing the "ARM STM STM32MP" maintainers for arm_pl180
changes, they use the STM32_MMCI_ID code path in this driver and
reviewed/tested my last changes (Patrice Chotard in particular).

Thanks,
Stephan