RFC: PHY Abstraction Layer II

Benjamin Herrenschmidt benh at kernel.crashing.org
Fri Mar 11 10:06:32 EST 2005


On Thu, 2005-03-10 at 23:01 +0000, James Chapman wrote:
> Hi Andy,
> 
> Can you elaborate on why this phy abstraction is needed?
> 
> In your original post, you mentioned that you were going to post a
> patch to show how your code would be hooked up in an existing net
> driver. Did I miss it? It would help in understanding the pros and cons
> of using genphy over using plain old mii.c.
> 
> btw, I recently posted a patch to add GigE support to mii.c which is
> in Jeff's netdev-2.6 queue. Some register definitions were added in
> mii.h that will collide with yours.

A variety of PHY chips require special cases that aren't handled by the
generic mii code. The PHY driver layer allows to plug PHY specific
drivers, with genphy just being the "default" for sane chips.

Also, I think Andy added more to the PHY layer than what mii does, like
support for the interrupt or timer based link management etc... which
tend to be the same in a lot of drivers.

Ben.





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