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Date:   Sun, 25 Oct 2020 02:39:05 +0800
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Subject: Re: [linux-sunxi] [PATCH 02/10] ARM: dts: sun6i: a31-hummingbird: Enable RGMII RX/TX delay on Ethernet PHY
To:     jernej.skrabec@siol.net,
        =?UTF-8?Q?Jernej_=C5=A0krabec?= <jernej.skrabec@siol.net>,
        wens@kernel.org, Maxime Ripard <mripard@kernel.org>
CC:     linux-sunxi@googlegroups.com, Chen-Yu Tsai <wens@csie.org>,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
From:   Icenowy Zheng <icenowy@aosc.io>
Message-ID: <9D317C52-5F28-41A9-80DA-DBADA142B042@aosc.io>
Precedence: bulk


=E4=BA=8E 2020=E5=B9=B410=E6=9C=8825=E6=97=A5 GMT+08:00 =E4=B8=8A=E5=8D=88=
2:30:35, "Jernej =C5=A0krabec" <jernej=2Eskrabec@siol=2Enet> =E5=86=99=E5=
=88=B0:
>Dne sobota, 24=2E oktober 2020 ob 19:51:06 CEST je Icenowy Zheng
>napisal(a):
>> =E5=9C=A8 2020-10-25=E6=98=9F=E6=9C=9F=E6=97=A5=E7=9A=84 00:25 +0800=EF=
=BC=8CChen-Yu Tsai=E5=86=99=E9=81=93=EF=BC=9A
>>=20
>> > From: Chen-Yu Tsai <wens@csie=2Eorg>
>> >=20
>> > The Ethernet PHY on the A31 Hummingbird has the RX and TX delays
>> > enabled on the PHY, using pull-ups on the RXDLY and TXDLY pins=2E
>> >=20
>> > Fix the phy-mode description to correct reflect this so that the
>> > implementation doesn't reconfigure the delays incorrectly=2E This
>> > happened with commit bbc4d71d6354 ("net: phy: realtek: fix rtl8211e
>> > rx/tx delay config")=2E
>>=20
>> Personally I think they should revert this commit, and consider other
>> solution=2E
>>=20
>> This commit breaks everything=2E
>>=20
>
>Previously broken driver allowed inproper DT to work, so you have to
>fix=20
>everything eventually=2E

There is no "improper DT" if it's already shipped, DT should suffer driver
change, not changed to match driver=2E

I think at least Fedora tends to ship a DT with a system image that will
not get updated when kernel gets updated=2E

>
>Plus side, there is no need to have hack for Pine64 Plus ethernet
>anymore=2E
>
>Best regards,
>Jernej
>
>> (Although the patch on individual DT patches are technically correct)
>>=20
>> > Fixes: c220aec2bb79 ("ARM: dts: sun6i: Add Merrii A31 Hummingbird
>> > support")
>> > Signed-off-by: Chen-Yu Tsai <wens@csie=2Eorg>
>> > ---
>> >=20
>> >  arch/arm/boot/dts/sun6i-a31-hummingbird=2Edts | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >=20
>> > diff --git a/arch/arm/boot/dts/sun6i-a31-hummingbird=2Edts
>> > b/arch/arm/boot/dts/sun6i-a31-hummingbird=2Edts
>> > index 049e6ab3cf56=2E=2E73de34ae37fd 100644
>> > --- a/arch/arm/boot/dts/sun6i-a31-hummingbird=2Edts
>> > +++ b/arch/arm/boot/dts/sun6i-a31-hummingbird=2Edts
>> > @@ -154,7 +154,7 @@ &gmac {
>> >=20
>> >  	pinctrl-names =3D "default";
>> >  	pinctrl-0 =3D <&gmac_rgmii_pins>;
>> >  	phy-handle =3D <&phy1>;
>> >=20
>> > -	phy-mode =3D "rgmii";
>> > +	phy-mode =3D "rgmii-id";
>> >=20
>> >  	status =3D "okay";
>> > =20
>> >  };