netdev - Re: [PATCH net-next v6 5/5] net: phy: dp83td510: add MSE interface support for 10BASE-T1L

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Message-ID: <fb45668f-e13b-4a90-b0aa-e989e19b3c37@bootlin.com>
Date: Fri, 17 Oct 2025 16:20:39 +0200
From: Maxime Chevallier <maxime.chevallier@...tlin.com>
To: Oleksij Rempel <o.rempel@...gutronix.de>, Andrew Lunn <andrew@...n.ch>,
 Jakub Kicinski <kuba@...nel.org>, "David S. Miller" <davem@...emloft.net>,
 Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>,
 Simon Horman <horms@...nel.org>, Donald Hunter <donald.hunter@...il.com>,
 Jonathan Corbet <corbet@....net>, Heiner Kallweit <hkallweit1@...il.com>,
 Russell King <linux@...linux.org.uk>,
 Kory Maincent <kory.maincent@...tlin.com>, Nishanth Menon <nm@...com>
Cc: kernel@...gutronix.de, linux-kernel@...r.kernel.org,
 netdev@...r.kernel.org, UNGLinuxDriver@...rochip.com,
 linux-doc@...r.kernel.org, Michal Kubecek <mkubecek@...e.cz>,
 Roan van Dijk <roan@...tonic.nl>
Subject: Re: [PATCH net-next v6 5/5] net: phy: dp83td510: add MSE interface
 support for 10BASE-T1L

Hi Oleksij,

On 17/10/2025 12:47, Oleksij Rempel wrote:
> Implement get_mse_capability() and get_mse_snapshot() for the DP83TD510E
> to expose its Mean Square Error (MSE) register via the new PHY MSE
> UAPI.
> 
> The DP83TD510E does not document any peak MSE values; it only exposes
> a single average MSE register used internally to derive SQI. This
> implementation therefore advertises only PHY_MSE_CAP_AVG, along with
> LINK and channel-A selectors. Scaling is fixed to 0xFFFF, and the
> refresh interval/number of symbols are estimated from 10BASE-T1L
> symbol rate (7.5 MBd) and typical diagnostic intervals (~1 ms).
> 
> For 10BASE-T1L deployments, SQI is a reliable indicator of link
> modulation quality once the link is established, but it does not
> indicate whether autonegotiation pulses will be correctly received
> in marginal conditions. MSE provides a direct measurement of slicer
> error rate that can be used to evaluate if autonegotiation is likely
> to succeed under a given cable length and condition. In practice,
> testing such scenarios often requires forcing a fixed-link setup to
> isolate MSE behaviour from the autonegotiation process.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@...gutronix.de>

Reviewed-by: Maxime Chevallier <maxime.chevallier@...tlin.com>

Maxime