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

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

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@pengutronix.de>

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

Maxime