Re: [RFC fs_enet: Convert MII bitbang driver to use GPIO lib

[Laurent Pinchart <laurentp@cse-semaphore.com>]

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On Wednesday 16 April 2008 18:09, Laurent Pinchart wrote:
> On Wednesday 16 April 2008 18:05, Anton Vorontsov wrote:
> > On Wed, Apr 16, 2008 at 04:40:42PM +0200, Laurent Pinchart wrote:
> > > This patch converts the MII bitband driver to use GPIO lib for GPIO
> > > access. The driver can now handle MDC and MDIO on different GPIO banks.
> > > 
> > > The patch depends on Anton Vorontsov GPIO lib support scheduled for
> > > 2.6.26. It is by no means complete, I just would like to get some
> > > feedback on the approach. I'll resubmit it when the CPM2 GPIO support
> > > patches will be available in the powerpc git tree.
> > 
> > Cool! By the way, maybe it is worth splitting it into completely separate
> > driver, e.g. net/mdio_gpio.c?
> 
> Splitting it into a completely separate driver makes sense.
>
> > Plus, keep in mind that somebody will eventually want this cool stuff with
> > platform_device bindings in addition. :-) 
> 
> I'm sure that person will be happy to implement platform_device bindings :-)

I had a first try at moving mdio gpio code into a separate driver.

Very little code is OF-independant, so the driver should probably be called 
mdio_of_gpio.c or mdio_ofgpio.c.

Scott Wood was concerned in 
http://patchwork.ozlabs.org/linuxppc/patch?id=17490 that the gpio lib might 
be an unnecessary burden for memory-constraint platforms. Should we keep two 
mdio bitbang drivers, one with direct access to the ports and one using gpio 
lib ? The later solves the concurrent access issues present in the current 
fs_enet mdio bitbang driber.

I'll submit a patch for whichever solution gets selected (modifying the 
current fs enet mdio bitbang driver to use the gpio lib, or creating a new 
driver).

-- 
Laurent Pinchart
CSE Semaphore Belgium

Chaussee de Bruxelles, 732A
B-1410 Waterloo
Belgium

T +32 (2) 387 42 59
F +32 (2) 387 42 75

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