netdev - Re: [PATCH] ARM64: dts: mediatek: fix MT7531 reset polarity and reset sequence

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: <f8e9184a-2b29-461a-907b-9e17856b5d89@lunn.ch>
Date: Thu, 20 Nov 2025 22:09:28 +0100
From: Andrew Lunn <andrew@...n.ch>
To: Chen Minqiang <ptpt52@...il.com>
Cc: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Matthias Brugger <matthias.bgg@...il.com>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	"Chester A. Unal" <chester.a.unal@...nc9.com>,
	Daniel Golle <daniel@...rotopia.org>,
	DENG Qingfang <dqfext@...il.com>,
	Sean Wang <sean.wang@...iatek.com>, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-mediatek@...ts.infradead.org, netdev@...r.kernel.org
Subject: Re: [PATCH] ARM64: dts: mediatek: fix MT7531 reset polarity and
 reset sequence

On Fri, Nov 21, 2025 at 12:22:24AM +0800, Chen Minqiang wrote:
> The MT7531 reset pin is active-low, but multiple MediaTek boards describe
> the reset-gpios property without GPIO_ACTIVE_LOW or incorrectly mark it
> as active-high. With an active-low GPIO, gpiod_set_value(1) drives the
> line low (assert reset) and gpiod_set_value(0) drives it high (deassert).
> 
> Update all affected DTS files to explicitly use GPIO_ACTIVE_LOW so that
> the reset polarity matches the hardware design.
> 
> Additionally, adjust the mt7530 driver reset sequence to correctly assert
> reset by driving the GPIO low first, wait for the reset interval, and
> then deassert reset by driving the GPIO high.
> 
> Boards fixed:
>  - mt7622-bananapi-bpi-r64
>  - mt7622-rfb1
>  - mt7986a-bananapi-bpi-r3
>  - mt7986a-rfb
>  - mt7986b-rfb
> 
> This ensures the MT7531 receives a proper low-to-high active-low reset
> pulse and initializes reliably.

Please add a comment to the commit message about backwards/forwards
compatibility, how this is safe when booting an old DT blob on a new
kernel. Or a new DT blob on an old kernel. We don't expect regressions
in such cases, and it is good to indicate in the commit message you
have thought about this and don't expect problems.

    Andrew

---
pw-bot: cr