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

[Andrew Lunn]

On Thu, Dec 02, 2021 at 06:46:40PM +0000, Wells Lu 呂芳騰 wrote:
> 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