netdev - Re: [PATCH net-next 0/3] net: phy: Support enabling clocks prior to bus probe

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Date:   Fri, 4 Sep 2020 15:58:53 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     netdev@...r.kernel.org, adam.rudzinski@....net.pl,
        m.felsch@...gutronix.de, hkallweit1@...il.com,
        richard.leitner@...data.com, zhengdejin5@...il.com,
        devicetree@...r.kernel.org, kernel@...gutronix.de, kuba@...nel.org,
        robh+dt@...nel.org
Subject: Re: [PATCH net-next 0/3] net: phy: Support enabling clocks prior to
 bus probe

On Thu, Sep 03, 2020 at 09:04:11PM -0700, Florian Fainelli wrote:
> 
> 
> On 9/2/2020 9:39 PM, Florian Fainelli wrote:
> > Hi all,
> > 
> > This patch series takes care of enabling the Ethernet PHY clocks in
> > DT-based systems (we have no way to do it for ACPI, and ACPI would
> > likely keep all of this hardware enabled anyway).
> > 
> > Please test on your respective platforms, mine still seems to have
> > a race condition that I am tracking down as it looks like we are not
> > waiting long enough post clock enable.
> > 
> > The check on the clock reference count is necessary to avoid an
> > artificial bump of the clock reference count and to support the unbind
> > -> bind of the PHY driver. We could solve it in different ways.
> > 
> > Comments and test results welcome!
> 
> Andrew, while we figure out a proper way to support this with the Linux
> device driver model, would you be opposed in a single patch to
> drivers/net/mdio/mdio-bcm-unimac.c which takes care of enabling the PHY's
> clock during bus->reset just for the sake of getting those systems to work,
> and later on we move over to the pre-probe mechanism?
> 
> That would allow me to continue working with upstream kernels on these
> systems without carrying a big pile of patches.

We do have quite a need for the proper solution. I wouldn't want you
dropping the proper solution because you have a hack in place.

Please add a comment: "HORRIBLE TEMPORARY HACK", to give you
motivation to remove it again :-)

   Andrew