Subject: RE: [PATCH net-next 4/7] net: pcs: xpcs: adapt Wangxun NICs for SGMII mode

From: Jiawen Wu <[email-masked]>
Date: Mon, 31 Jul 2023 09:47:40 +0800

On Friday, July 28, 2023 6:24 PM, : Andrew Lunn wrote:
> > There is a question about I2C MII read ops. I see that PHY in SFP-RJ45 module
> > is read by i2c_mii_read_default_c22(), but it limits the msgs[0].len=1.
> >
> > A description in  the SFP-RJ45 datasheet shows:
> 
> Please give a link to this document.

https://www.alldatasheet.com/datasheet-pdf/pdf/465165/AVAGO/ABCU-5710RZ.html

> 
> The problem with copper PHYs embedded inside SFPs is that there is no
> standardised protocol to talk to them. Each PHY vendor does their own
> thing. At the moment, two different protocols are supported, ROLLBALL
> and the default protocol. It might be another protocol needs to be
> added to support the SFP you are testing with. So we need to see the
> protocol specification.
> 
>       Andrew
>