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

[Liang Xu <lxu@maxlinear.com>]

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:
>> On 5/6/2021 3:44 am, Martin Blumenstingl wrote:
>>> This email was sent from outside of MaxLinear.
>>>
>>>
>>> Hello,
>>>
>>>> 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.
>
>> 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.
>
>> 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.
>
>> 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