Re: [PATCH v3] net: phy: add Maxlinear GPY115/21x/24x driver

On 6/6/2021 1:24 am, Andrew Lunn wrote:

This email was sent from outside of MaxLinear.


On Sat, Jun 05, 2021 at 03:32:39AM +0000, Liang Xu wrote:

quoted

On 5/6/2021 3:44 am, Martin Blumenstingl wrote:

quoted

This email was sent from outside of MaxLinear.


Hello,

quoted

Add driver to support the Maxlinear GPY115, GPY211, GPY212, GPY215,
GPY241, GPY245 PHYs.

to me this seems like an evolution of the Lantiq XWAY PHYs for which
we already have a driver: intel-xway.c.
Intel took over Lantiq some years ago and last year MaxLinear then
took over what was formerly Lantiq from Intel.

  From what I can tell right away: the interrupt handling still seems
to be the same. Also the GPHY firmware version register also was there
on older SoCs (with two or more GPHYs embedded into the SoC). SGMII
support is new. And I am not sure about Wake-on-LAN.

Have you considered adding support for these new PHYs to intel-xway.c?

The WOL interrupts are the same, which could imply WoL configuration
is the same? If it is the same, it would be good to also add WoL to
intel-xway.c.

What this new driver does not yet do is LEDs. It would be interesting
to see if the LED control is the same. Hopefully, one day, generic LED
support will get added. If this PHY and intel-xway.c has the same LED
code, we will want to share it.

quoted

They are based on different IP and have many differences.

Please could you list the differences? Is the datasheet available?  I
found a datasheet for the XWAY, so it would be nice to be able to
compare them.

quoted

The XWAY PHYs are going to EoL (or maybe already EoL).

That does not matter. They are going to be in use for the next 5 years
or more, until all the products using them have died or been
replaced. Linux supports hardware that is in use, not just what
vendors sell today.

quoted

It creates difficulty for the test coverage to put together.

That also does not really matter. If somebody has both, does the work
to merge the drivers and overall we have less code and more features,
the patch will be accepted.


         Andrew

The datasheet of GPY2xx are only available under NDA currently, since we 
have

to protect our IP for the new devices.

I do not know much about XWAY feature set, but I guess the difference should

be 2.5G support, C45 register set, PTP offload, MACsec offload, etc.

Problem of merging the both drivers would be the verification of the old 
devices

for which I do not have a test environment. I can't deliver code without 
testing,

and it will be big problem for me if it breaks function of existing 
user/customer.

We will check for options and need approval from company, but this will 
not be

possible short term within this merge window.

For now, can I upstream this new driver first, and merge the old driver 
into new one later?

We will enhance the new driver step by step with different features, but 
currently

we would like to make the first version available and working for our 
customers.


Thanks & Regards,

Xu Liang