Re: [PATCH] arm64: dts: renesas: add full-pwr-cycle-in-suspend into eMMC nodes

From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: Magnus Damm <magnus.damm@gmail.com>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH] arm64: dts: renesas: add full-pwr-cycle-in-suspend into eMMC nodes
Date: Fri, 17 Jul 2020 12:07:00 +0200	[thread overview]
Message-ID: <CAMuHMdUkzNx2nUrRN+0bny6BG95YVNqUiWN2L+BXsOD_o-=Vfg@mail.gmail.com> (raw)
In-Reply-To: <TY2PR01MB36923CD412750CE20F416A45D87C0@TY2PR01MB3692.jpnprd01.prod.outlook.com>

Hi Shimoda-san,

On Fri, Jul 17, 2020 at 12:02 PM Yoshihiro Shimoda
<yoshihiro.shimoda.uh@renesas.com> wrote:
> > From: Geert Uytterhoeven, Sent: Friday, July 17, 2020 5:35 PM
> > On Fri, Jul 17, 2020 at 10:29 AM Yoshihiro Shimoda
> > <yoshihiro.shimoda.uh@renesas.com> wrote:
> > > > From: Geert Uytterhoeven, Sent: Friday, July 17, 2020 4:13 PM
> > > > On Fri, Jul 17, 2020 at 7:44 AM Yoshihiro Shimoda
> > > > <yoshihiro.shimoda.uh@renesas.com> wrote:
> > > > > > From: Geert Uytterhoeven, Sent: Wednesday, July 15, 2020 6:05 PM
> > > > > > On Fri, Jul 10, 2020 at 2:03 PM Yoshihiro Shimoda
> > > > > > <yoshihiro.shimoda.uh@renesas.com> wrote:
> > > <snip>
> > > > > > >  arch/arm64/boot/dts/renesas/r8a77990-ebisu.dts   | 1 +
> > > > > > >  arch/arm64/boot/dts/renesas/salvator-common.dtsi | 1 +
> > > > > >
> > > > > > I assume we need this on other boards, too?
> > > > > > At least ULCB uses the BD9571 PMIC, and has a similar PSCI s2ram
> > > > > > implementation as Salvator-X(S) and Ebisu.
> > > > >
> > > > > I think so. And, I also thin ULCB+KF should not have this because
> > > > > it doesn't support Suspend-to-RAM. But, what do you think?
> > > >
> > > > How come ULCB+KF doesn't support s2ram?
> > > > Isn't KingFisher just an extension board for ULCB?
> > > > Does it require a firmware upgrade?
> > >
> > > It's related to board design. If ULCB+KF, we must not use 5V AC to ULCB side
> > > and must use 12V AC to KF side. And KF has power switch as SW6 for both ULCB+KF.
> > > https://elinux.org/R-Car/Boards/Kingfisher
> >
> > OK.
> >
> > > However, PMIC on ULCB cannot control the KF power unfortunately.
> > > So, we have no chance to use s2ram on ULCB+KF...
> >
> > Makes sense.
> > BTW, what happens if you try s2ram? I guess the system just wakes up again
> > immediately? Or does it crash?
>
> It's frozen after s2ram. Some LEDs on ULCB is OFF. But, LEDs on KF is still ON.

Oops.

> So, I'm wondering if it's better to add the property on ULCB+KF too
> because it seems ULCB is turned off. But, what do you think?

IMHO, a graceful shutdown is better.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds