linux-kernel - Re: Re: Re: [PATCH v2] ARM: dts: sun8i-r40: remove unused GPIO regulator

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20250214150543.GA9779@lemon.iwr.uni-heidelberg.de>
Date: Fri, 14 Feb 2025 16:05:43 +0100
From: Hermann.Lauer@...-heidelberg.de
To: Chen-Yu Tsai <wens@...e.org>
Cc: Icenowy Zheng <uwu@...nowy.me>, Andre Przywara <andre.przywara@....com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	Samuel Holland <samuel@...lland.org>, devicetree@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Subject: Re: Re: Re: [PATCH v2] ARM: dts: sun8i-r40: remove unused GPIO
 regulator

On Mon, Dec 23, 2024 at 01:18:18AM +0800, Chen-Yu Tsai wrote:
> > > > CC:ing Icenowy, who added the regulator originally, with commit
> > > > 0ca12c1ee43c ("ARM: sun8i: r40: add 5V regulator for Banana Pi M2
> > > > Ultra").
> > ...
> > > > Icenowy: can you clarify what "newer" version this was referring to
> > > > in
> > > > that commit message? That commit in itself doesn't seem to do
> > > > anything,
> > > > as the regulator isn't referenced, and it's not always-on. It's only
> > > > later when the USB nodes were added that it got used?
> > > > So was PH23 really necessary?
...
> > diagnosed that futher now: PH23 is indeed powering the USB-Ports. Whats
> > happens ist that I powered the board through the micro USB port which turned
> > out to be limited to 900mA in axp221s. So the setting of reg 0x30 is
> > the real culprit: Setting the two lowest bits in this register allows
> > unlimited power over micro usb.
...
> > > I am not sure, the schematics I have here (which says V1.0) have PH23
> > > as NC... Well, the M2 Berry schematics have PH23 as 5V EN, maybe I
> > > messed up M2U and M2B when developing?
> >
> > While V1.0 didn't need the PH23 setup due to nc, V1.1 needs it. Maybe V1.1
> > was already on the horizon...
> 
> It seems this patch isn't needed then?

It's plain wrong: The culprit is the power issue as discussed above. Strange
is the increase of power needed on V1.1, as V1.0 is working with the limit
in place.

As there are issues with the stability of the mmc driver even when disabling
mmc2 and mmc3, maybe something yet to be found changed in the mmc wirering
on V1.1 bords which increases power consumption compared to V1.0 with the
actual driver.

Sorry for the late reply - my time to look at this is scarse.
Thanks (especially to Andre for his help) and greetings
 Hermann