Date: Mon, 11 Jun 2012 16:23:11 +0200
From: Alessandro Rubini <rubini@gnudd.com>
To: wg@grandegger.com
Cc: alan@lxorguk.ukuu.org.uk, federico.vaga@gmail.com, mkl@pengutronix.de,
        giancarlo.asnaghi@st.com, alan@linux.intel.com,
        linux-can@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC] c_can_pci: generic module for c_can on PCI
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>> In my opinion, it would be much better to have one less layer and no
>> exports at all. The core driver should be a platform driver, and the
>> pci driver would just build platform data and register the platform
>> device.
> 
> Do you have examples for that approach? Not sure yet if it really saves
> code and makes it more readable.

Maybe the physmap mtd driver is a good example. Everybody's using it
(but not from PCI). I found drivers/pcmcia/bcm63xx_pcmcia.c that
registers a platform driver from a pci probe function, but I'm sure
there are other ones.

OTOH, I have another example of how not to do stuff, but I won't point
fingers now (it's not a CAN thing).

I just think the platform bus is there just for this reason: to provide
data to a generic driver, without module dependencies and such stuff. 

> I would suggest to provide the c_can_pci driver using the *current* API,
> even if it's not optimal. Federicos patch then already looks quite good.
> It should use the new register access methods introduced by the D_CAN
> support patch, though.

Great. When it's in I'll show my proposal as an RFC patch, as time permits,
so we'll see if it's better or not.

> Any further improvements to the device abstraction and a more consistent
> handling of the platform data are welcome.

Good to know, thanks a lot

/alessandro
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