netdev - Re: [PATCH 2/2] net: ethernet: fsl: add phy reset after clk enable option

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Message-ID: <b68f444e-cea4-acaa-d1e9-7955a577ed35@skidata.com>
Date:   Fri, 7 Jul 2017 13:16:54 +0200
From:   Richard Leitner <richard.leitner@...data.com>
To:     Andy Duan <fugang.duan@....com>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "mark.rutland@....com" <mark.rutland@....com>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "dev@...l1n.net" <dev@...l1n.net>, Andrew Lunn <andrew@...n.ch>
Subject: Re: [PATCH 2/2] net: ethernet: fsl: add phy reset after clk enable
 option

Hi Andy,
thanks for the clarifications!

On 07/07/2017 01:08 PM, Andy Duan wrote:
>> 3. Who should then trigger the "hard reset" of the PHY? phy_init_hw? The FEC?
>>
>> The point is that the LAN8710 is currently not always working correctly,
>> therefore this small change was proposed. Should we really change all
>> PHY/FECs only because of this?
>> Furthermore one problem still remains: The enet_refclk is controlled by the
>> FEC. How does the PHY recognize when it was disabled/enabled?
>>
> Your patch is workaround for the issue. As you pointed out these is a common issue.
> So we hope to get a better solution to handle these in common code.

Ok. I'm fine with moving the phy-reset-gpios binding into the PHY. But 
one question still remains: Who should then trigger the "hard reset" of 
the PHY?

The PHY itself doesn't "know" when the refclk is turned off/on. So the 
FEC still must call some function of the PHY after the clock was enabled 
again. So the phy-reset-after-clk-enable property will remain in the fec 
node? Or am I missing something?