Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Content-Type: text/plain;
        charset=us-ascii
Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.100.0.2.22\))
Subject: Re: [PATCH] net: phy: micrel: Fix detection of ksz87xx switch
From:   Steve Bennett <steveb@workware.net.au>
In-Reply-To: <20210807000123.GA4898@cephalopod>
Date:   Mon, 9 Aug 2021 08:18:28 +1000
Cc:     Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Content-Transfer-Encoding: quoted-printable
Message-Id: <F8C5F7CD-343A-4C25-B04B-EEA5C086B693@workware.net.au>
References: <20210730105120.93743-1-steveb@workware.net.au>
 <20210730095936.1420b930@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
 <74BE3A85-61E2-45C9-BA77-242B1014A820@workware.net.au>
 <20210807000123.GA4898@cephalopod>
To:     Ben Hutchings <ben.hutchings@essensium.com>
Precedence: bulk


> On 7 Aug 2021, at 10:01 am, Ben Hutchings =
<ben.hutchings@essensium.com> wrote:
>=20
> On Sat, Jul 31, 2021 at 08:19:17AM +1000, Steve Bennett wrote:
>>> On 31 Jul 2021, at 2:59 am, Jakub Kicinski <kuba@kernel.org> wrote:
>>>=20
>>> Please extend the CC list to the maintainers, and people who
>>> worked on this driver in the past, especially Marek.
>>=20
>> Sure, I can do that in a v2 of the patch along with the more detailed
>> explanation below.
>>=20
>>>=20
>>> On Fri, 30 Jul 2021 20:51:20 +1000 Steve Bennett wrote:
>>>> The previous logic was wrong such that the ksz87xx
>>>> switch was not identified correctly.
>>>=20
>>> Any more details of what is happening? Which extact device do you =
see
>>> this problem on?
>>=20
>> I have a ksz8795 switch.
>>=20
>> Without the patch:
>>=20
>> ksz8795-switch spi3.1 ade1 (uninitialized): PHY [dsa-0.1:03] driver =
[Generic PHY]
>> ksz8795-switch spi3.1 ade2 (uninitialized): PHY [dsa-0.1:04] driver =
[Generic PHY]
>>=20
>> With the patch:
>>=20
>> ksz8795-switch spi3.1 ade1 (uninitialized): PHY [dsa-0.1:03] driver =
[Micrel KSZ87XX Switch]
>> ksz8795-switch spi3.1 ade2 (uninitialized): PHY [dsa-0.1:04] driver =
[Micrel KSZ87XX Switch]
> [...]
>=20
> And do the external ports work for you after this?
>=20
> I have a development board with a KSZ8795.  All ports worked before
> this patch.  After this patch, when I bring up the external ports they
> are reported as having link up at 10M half duplex, when the link is
> actually down.
>=20
> The ksz8873mll_read_status() function is trying to read a non-standard
> MDIO register that is not handled by the ksz8795 driver's MDIO
> emulation (and is not documented as existing on the KSZ8873MLL,
> either!).  It also also reports link up, which is obviously not
> correct for an external port.
>=20
> I'll post a patch as a reply to this.
>=20
> Ben.

Thanks Ben,

That looks reasonable to me. My board is running the external ports at =
10HD so
I didn't pick this up, but your patch looks correct.

Cheers,
Steve=