netdev - Re: [PATCH v1] net: phy: adin: Add flags to disable enhanced link detection

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Date:   Tue, 28 Feb 2023 15:53:11 +0100
From:   Andrew Lunn <andrew@...n.ch>
To:     Ken Sloat <ken.s@...iscite.com>
Cc:     Michael Hennerich <michael.hennerich@...log.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] net: phy: adin: Add flags to disable enhanced link
 detection

On Tue, Feb 28, 2023 at 09:40:56AM -0500, Ken Sloat wrote:
> Enhanced link detection is an ADI PHY feature that allows for earlier
> detection of link down if certain signal conditions are met. This
> feature is for the most part enabled by default on the PHY. This is
> not suitable for all applications and breaks the IEEE standard as
> explained in the ADI datasheet.
> 
> To fix this, add override flags to disable enhanced link detection
> for 1000BASE-T and 100BASE-TX respectively by clearing any related
> feature enable bits.
> 
> This new feature was tested on an ADIN1300 but according to the
> datasheet applies equally for 100BASE-TX on the ADIN1200.
> 
> Signed-off-by: Ken Sloat <ken.s@...iscite.com>
Hi Ken

> +static int adin_config_fld_en(struct phy_device *phydev)

Could we have a better name please. I guess it means Fast Link Down,
but the commit messages talks about Enhanced link detection. This
function is also not enabling fast link down, but disabling it, so _en
seems wrong.

> +{
> +	struct device *dev = &phydev->mdio.dev;
> +	int reg;
> +
> +	reg = phy_read_mmd(phydev, MDIO_MMD_VEND1, ADIN1300_FLD_EN_REG);
> +	if (reg < 0)
> +		return reg;
> +
> +	if (device_property_read_bool(dev, "adi,disable-fld-1000base-t"))

You need to document these two properties in the device tree binding.

Please also take a read of
https://www.kernel.org/doc/html/latest/process/maintainer-netdev.html#netdev-faq

    Andrew