Re: [PATCH v2 1/3] dt-bindings: net: fsl-fec add mdc/mdio bitbang option

From: Andrew Lunn
Date: Sun Nov 29 2020 - 18:07:49 EST


On Sun, Nov 29, 2020 at 11:51:43PM +0100, Adrien Grassein wrote:
> Hi Andrew,
>
> Please find my answers below.
>
> Le dim. 29 nov. 2020 à 23:41, Andrew Lunn <andrew@xxxxxxx> a écrit :
>
> On Sun, Nov 29, 2020 at 10:59:58PM +0100, Adrien Grassein wrote:
> > Add dt-bindings explanation for the two new gpios
> > (mdio and mdc) used for bitbanging.
>
> Hi Adrien
>
> What is missing is an explanation of why!
>
> I'm sorry, it's my first upstreaming attempt.

Hi Adrien

Please take a look at

https://www.kernel.org/doc/html/latest/networking/netdev-FAQ.html

It is normal to have a patch 0/X which explains the big picture.

Then the commit message for each patch should explain why you are
doing something. That is much more important than what you are doing,
i can see that from the patch itself.

> I am currently upstreaming the "Nitrogen 8m Mini board" that seems to not use a
> "normal" mdio bus but a "bitbanged" one with the fsl fec driver.

Any idea why?

Anyway, you should not replicate code, don't copy bitbanging code into
the FEC. Just use the existing bit-banger MDIO bus master driver.

Andrew