linux-kernel - Re: [PATCH 3/3] net: mdio: reset PHY before attempting to access registers in fwnode_mdiobus_register

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Message-ID: <0d0d7e6f-3376-4939-a3f7-8cf5f52e4749@lunn.ch>
Date: Wed, 9 Jul 2025 15:41:45 +0200
From: Andrew Lunn <andrew@...n.ch>
To: Buday Csaba <buday.csaba@...lan.hu>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	Csókás Bence <csokas.bence@...lan.hu>,
	Heiner Kallweit <hkallweit1@...il.com>,
	Russell King <linux@...linux.org.uk>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>
Subject: Re: [PATCH 3/3] net: mdio: reset PHY before attempting to access
 registers in fwnode_mdiobus_register_phy

On Wed, Jul 09, 2025 at 03:32:22PM +0200, Buday Csaba wrote:
> Some PHYs (e.g. LAN8710A) require a reset after power-on,even for
> MDIO register access.
> The current implementation of fwnode_mdiobus_register_phy() and
> get_phy_device() attempt to read the id registers without ensuring
> that the PHY had a reset before, which can fail on these devices.
> 
> This patch addresses that shortcoming, by always resetting the PHY
> (when such property is given in the device tree). To keep the code
> impact minimal, a change was also needed in phy_device_remove() to
> prevent asserting the reset on device removal.
> 
> According to the documentation of phy_device_remove(), it should
> reverse the effect of phy_device_register(). Since the reset GPIO
> is in undefined state before that, it should be acceptable to leave
> it unchanged during removal.
> 
> Signed-off-by: Buday Csaba <buday.csaba@...lan.hu>
> Cc: Csókás Bence <csokas.bence@...lan.hu>

This appears to be a respost of the previous patch.

https://www.kernel.org/doc/html/latest/process/maintainer-netdev.html says:

don’t repost your patches within one 24h period

    Andrew

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pw-bot: cr