# RE: \[PATCH net-next v3 2/2\] net: ethernet: Add driver for Sunplus SP7021

- From: Wells Lu 呂芳騰 \<hidden\>
- Date: 2021-12-03 01:38:17 
- List: linux-devicetree
- Page: https://ratatoskr.run/linux-devicetree/2021/12/1594922
- Thread: https://ratatoskr.run/netdev/2021/11/1591109/t.md

```text
Hi Andrew,

Thank you for explanation.


Best regards,
Wells Lu


> > Hi Andrew,
> >
> > Thank you for explanation.
> >
> > I'll add phy_support_asym_pause() after PHY connected next patch.
> >
> > I found some drivers call phy_set_max_speed() to set PHY speed to 100M
> > after PHY connected. Is that necessary?
> 
> > From 'supported', PHY supports 10M/100M already.
> 
> You need phy_set_max_speed() when it is possible to connect a 10/100 MAC to a 1G PHY.  You
> sometime do this because a 1G PHY is cheaper than a 100M PHY. Unless limited, the PHY will
> advertise and could negotiate a 1G link, but the MAC could then not support it. If it is
> not physically possible to connect a 1G PHY to your MAC, you don't need to worry.
> 
> > I also found some drivers call phy_start_aneg() after PHY started.
> 
> It is not needed.
> 
>    Andrew
```