linux-kernel - Re: [PATCH 1/3] arm64: dts: rockchip: adjust dcin regulator on ROCK 4D

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

Message-Id: <DB0KL629S4E4.3ENNM27XN3IYM@cknow.org>
Date: Tue, 01 Jul 2025 10:19:33 +0200
From: "Diederik de Haas" <didi.debian@...ow.org>
To: "Sebastian Reichel" <sebastian.reichel@...labora.com>
Cc: "Nicolas Frattaroli" <nicolas.frattaroli@...labora.com>, "Rob Herring"
 <robh@...nel.org>, "Krzysztof Kozlowski" <krzk+dt@...nel.org>, "Conor
 Dooley" <conor+dt@...nel.org>, "Heiko Stuebner" <heiko@...ech.de>,
 <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
 <linux-rockchip@...ts.infradead.org>, <kernel@...labora.com>,
 <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 1/3] arm64: dts: rockchip: adjust dcin regulator on ROCK
 4D

Hi,

On Tue Jul 1, 2025 at 1:10 AM CEST, Sebastian Reichel wrote:
> On Mon, Jun 30, 2025 at 08:12:27PM +0200, Diederik de Haas wrote:
>> On Mon Jun 30, 2025 at 5:36 PM CEST, Nicolas Frattaroli wrote:
>> > The ROCK 4D's actual DC input is 5V, and the schematic names it as being
>> > 5V as well.
>> >
>> > Rename the regulator, and change the voltage it claims to be at.
>> 
>> Shouldn't it have a fixes tag then? Providing 12V where 5V is expected
>> sounds problematic ;-)
>
> This is basically "just" documentation, as the DT just describes
> a fixed regulator (i.e. nothing software controllable). This just
> changes a number in sysfs :)
>
> Note, that the 5V DCIN is a USB-C port, which does not do any PD
> negotiation, but has the 5K1 resistors on the CC lines to "request"
> 5V. If for whatever reason a higher voltage is applied (which does
> not happen as long as the power is provided by anything remotely
> following the USB specifications) there also is an over-voltage
> protection chip. So it's not problematic :)

I was worried about and wondered why I/we did NOT receive reports about
boards being fried. Good to know, thanks!

> OTOH adding a Fixes tag does not hurt ;)

Cheers,
  Diederik

Download attachment "signature.asc" of type "application/pgp-signature" (229 bytes)