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    SubjectRE: [PATCH net 1/2] dt: ar803x: Document disable-hibernation property
    Date


    > -----Original Message-----
    > From: Andrew Lunn <andrew@lunn.ch>
    > Sent: 2022年8月18日 9:44
    > To: Wei Fang <wei.fang@nxp.com>
    > Cc: hkallweit1@gmail.com; linux@armlinux.org.uk; davem@davemloft.net;
    > edumazet@google.com; kuba@kernel.org; pabeni@redhat.com;
    > robh+dt@kernel.org; krzysztof.kozlowski+dt@linaro.org; f.fainelli@gmail.com;
    > netdev@vger.kernel.org; devicetree@vger.kernel.org;
    > linux-kernel@vger.kernel.org
    > Subject: Re: [PATCH net 1/2] dt: ar803x: Document disable-hibernation
    > property
    >
    > > Yes, after the PHY enters hibernation mode that the RX_CLK stop
    > > ticking, but for stmmac, it is essential that RX_CLK of PHY is present
    > > for software reset completion. Otherwise, the stmmac is failed to
    > > complete the software reset and can not init DMA.
    >
    > So the RX_CLK is more than the recovered clock from the bit stream on the
    > wire. The PHY has a way to generate a clock when there is no bit stream?
    >
    Yes, when disable hibernation mode, the RX_CLK always output a valid clock.

    > To me, it sounds like your hardware design is wrong, and it should be using the
    > 25MHz reference clock. And what you are proposing is a workaround for this
    > hardware problem.
    >
    > Anyway, i agree with Russell, a DT property is fine. But please make it clear in
    > the binding documentation that disabling hibernation has the side affect of
    > keeping the RX_CLK ticking when there is no link. That is probably what people
    > want this for, not to actual disable hibernation.
    >
    > Andrew
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