linux-kernel - Re: [PATCH net-next v4 2/2] net: mdio: mdio-i2c: Add support for single-byte SMBus operations

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Message-ID: <78b99da9-1e0e-4024-a4cb-b649caf0a5d2@lunn.ch>
Date: Sat, 22 Mar 2025 16:43:04 +0100
From: Andrew Lunn <andrew@...n.ch>
To: Maxime Chevallier <maxime.chevallier@...tlin.com>
Cc: davem@...emloft.net, Jakub Kicinski <kuba@...nel.org>,
	Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>,
	Russell King <linux@...linux.org.uk>,
	Heiner Kallweit <hkallweit1@...il.com>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, thomas.petazzoni@...tlin.com,
	Florian Fainelli <f.fainelli@...il.com>,
	Köry Maincent <kory.maincent@...tlin.com>,
	Simon Horman <horms@...nel.org>,
	Romain Gantois <romain.gantois@...tlin.com>,
	Antoine Tenart <atenart@...nel.org>,
	Marek Behún <kabel@...nel.org>,
	Sean Anderson <sean.anderson@...ux.dev>,
	Bjørn Mork <bjorn@...k.no>
Subject: Re: [PATCH net-next v4 2/2] net: mdio: mdio-i2c: Add support for
 single-byte SMBus operations

On Sat, Mar 22, 2025 at 08:57:45AM +0100, Maxime Chevallier wrote:
> PHYs that are within copper SFP modules have their MDIO bus accessible
> through address 0x56 (usually) on the i2c bus. The MDIO-I2C bridge is
> desgned for 16 bits accesses, but we can also perform 8bits accesses by
> reading/writing the high and low bytes sequentially.
> 
> This commit adds support for this type of accesses, thus supporting
> smbus controllers such as the one in the VSC8552.
> 
> This was only tested on Copper SFP modules that embed a Marvell 88e1111
> PHY.
> 
> Tested-by: Sean Anderson <sean.anderson@...ux.dev>
> Signed-off-by: Maxime Chevallier <maxime.chevallier@...tlin.com>

Reviewed-by: Andrew Lunn <andrew@...n.ch>

    Andrew