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References: <20201104160847.30049-1-TheSven73@gmail.com> <20201104162734.GA1249360@lunn.ch>
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From:   Sven Van Asbroeck <thesven73@gmail.com>
Date:   Wed, 4 Nov 2020 11:39:47 -0500
Message-ID: <CAGngYiUtMN0nOV+wZC-4ycwOAvU=BqhdP7Z3PUPh2GX8Fvo3jg@mail.gmail.com>
Subject: Re: [PATCH v1] lan743x: correctly handle chips with internal PHY
To:     Andrew Lunn <andrew@lunn.ch>
Cc:     Bryan Whitehead <bryan.whitehead@microchip.com>,
        David S Miller <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>,
        Roelof Berg <rberg@berg-solutions.de>,
        netdev <netdev@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Hi Andrew, many thanks for looking at this patch !

On Wed, Nov 4, 2020 at 11:27 AM Andrew Lunn <andrew@lunn.ch> wrote:
>
> > Note that as a side-effect, the devicetree phy mode now no longer
> > has a default, and always needs to be specified explicitly (via
> > 'phy-connection-type').
>
> That sounds like it could break systems. Why do you do this?

Because the standard mdio library function (of_phy_get_and_connect())
does not appear to support a default value. The original driver
code duplicated that library function's code, with a slight
tweak - the default value.

The default value was introduced quite recently, in the commit which
this patch fixes:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/drivers/net/ethernet/microchip/lan743x_main.c?h=v5.9.3&id=6f197fb63850b26ef8f70f1bfe5900e377910a5a

I'm not sure if other devices that specify phys in devicetrees have a
default for 'phy-connection-type'. I'm wondering if any do?