From:   Ken Sloat <ken.s@variscite.com>
To:     Andrew Lunn <andrew@lunn.ch>
CC:     Michael Hennerich <michael.hennerich@analog.com>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Ken Sloat <ken.s@variscite.com>
Subject: RE: [PATCH v1] net: phy: adin: Add flags to disable enhanced link
 detection
Thread-Topic: [PATCH v1] net: phy: adin: Add flags to disable enhanced link
 detection
Thread-Index: AQHZS4L7Pv2IgKC+70qPmaRcnFBcv67kcbqAgAAD6KA=
Date:   Tue, 28 Feb 2023 15:13:59 +0000
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References: <20230228144056.2246114-1-ken.s@variscite.com>
 <Y/4VV6MwM9xA/3KD@lunn.ch>
In-Reply-To: <Y/4VV6MwM9xA/3KD@lunn.ch>
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Hi Andrew,=0A=
=0A=
Thanks for your quick reply!=0A=
=0A=
> -----Original Message-----=0A=
> From: Andrew Lunn <andrew@lunn.ch>=0A=
> Sent: Tuesday, February 28, 2023 9:53 AM=0A=
> To: Ken Sloat <ken.s@variscite.com>=0A=
> Cc: Michael Hennerich <michael.hennerich@analog.com>; Heiner Kallweit=0A=
> <hkallweit1@gmail.com>; Russell King <linux@armlinux.org.uk>; David S.=0A=
> Miller <davem@davemloft.net>; Jakub Kicinski <kuba@kernel.org>;=0A=
> netdev@vger.kernel.org; linux-kernel@vger.kernel.org=0A=
> Subject: Re: [PATCH v1] net: phy: adin: Add flags to disable enhanced lin=
k=0A=
> detection=0A=
> =0A=
> On Tue, Feb 28, 2023 at 09:40:56AM -0500, Ken Sloat wrote:=0A=
> > Enhanced link detection is an ADI PHY feature that allows for earlier=
=0A=
> > detection of link down if certain signal conditions are met. This=0A=
> > feature is for the most part enabled by default on the PHY. This is=0A=
> > not suitable for all applications and breaks the IEEE standard as=0A=
> > explained in the ADI datasheet.=0A=
> >=0A=
> > To fix this, add override flags to disable enhanced link detection for=
=0A=
> > 1000BASE-T and 100BASE-TX respectively by clearing any related feature=
=0A=
> > enable bits.=0A=
> >=0A=
> > This new feature was tested on an ADIN1300 but according to the=0A=
> > datasheet applies equally for 100BASE-TX on the ADIN1200.=0A=
> >=0A=
> > Signed-off-by: Ken Sloat <ken.s@variscite.com>=0A=
> Hi Ken=0A=
> =0A=
> > +static int adin_config_fld_en(struct phy_device *phydev)=0A=
> =0A=
> Could we have a better name please. I guess it means Fast Link Down, but=
=0A=
> the commit messages talks about Enhanced link detection. This function is=
=0A=
> also not enabling fast link down, but disabling it, so _en seems wrong.=
=0A=
> =0A=
"Enhanced Link Detection" is the ADI term, but the associated register for =
controlling this feature is called "FLD_EN." I considered "ELD" as that mak=
es more sense language wise but it did not match the datasheet and did not =
want to invent a new term. I was not sure what the F was but perhaps you ar=
e right, as the link is brought down as part of this feature when condition=
s are met. I am guessing then that this FLD is a carryover from some initia=
l name of the feature that was later re-branded.=0A=
=0A=
I am happy to change fld -> eld or something else that might make more sens=
e for users and am open to any suggestions.=0A=
=0A=
> > +{=0A=
> > +	struct device *dev =3D &phydev->mdio.dev;=0A=
> > +	int reg;=0A=
> > +=0A=
> > +	reg =3D phy_read_mmd(phydev, MDIO_MMD_VEND1,=0A=
> ADIN1300_FLD_EN_REG);=0A=
> > +	if (reg < 0)=0A=
> > +		return reg;=0A=
> > +=0A=
> > +	if (device_property_read_bool(dev, "adi,disable-fld-1000base-t"))=0A=
> =0A=
> You need to document these two properties in the device tree binding.=0A=
> =0A=
=0A=
I already have a separate patch for this. I will send both patches when I r=
e-submit and CC additional parties.=0A=
=0A=
> Please also take a read of=0A=
> https://www.kernel.org/doc/html/latest/process/maintainer-=0A=
> netdev.html#netdev-faq=0A=
> =0A=
>     Andrew=0A=
=0A=
Sincerely,=0A=
Ken Sloat=0A=