Re: [PATCH v5 1/2] stmmac: dwmac-mediatek: enable 2ns delay only for special cases

[Biao Huang (黄彪)]

Dear Andrew,
	Thanks for your comments~

On Mon, 2022-12-26 at 16:19 +0100, Andrew Lunn wrote:
> > We don't want to restrict phy-mode to rgmii-id only, so I don't
> > think
> > we need mask RXID bit, then, User can use rgmii-rxid/-txid/-id as
> > their
> > will.
> 
> The phy-mode is a property of the board. It describes what delays are
> required, in addition to what the board itself provides via extra
> long
> lines. As such, there is no choice, it is set by physics.
> 
> How you implement those delays is then up to the MAC and PHY. 95% of
> all MAC drivers simply pass phy-mode to the PHY and let the PHY add
> the delays. The Renesas MAC driver is one of the exceptions, it often
> adds the delays, and then passes a different phy-mode to the PHY in
> order that there are not double delays.
> 
> So you can be different to everybody else, have MAC do one delay, and
> the PHY do the other. Just be aware that nobody else does this, no DT
> developers will expect it, etc.
> 
> Or you can just do what everybody else does and let the PHY add the
> delays.
> 
> What some MACs do is implement rx-internal-delay-ps and
> tx-internal-delay-ps These allow fine tuning of the delays. These are
> expected to be small values, adding 10s or 100s of pico seconds. They
> are not expected to be 2000ps.
OK, as to this series, Is the following modification enough?
    1. phy-mode = rgmii-id;  in dts.
    2. remove the fix_mac_speed() in driver.
> 
>     Andrew
Best Regards!
Biao