Subject: Re: [PATCH][RFC] PCMCIA support for 8xx using platform devices

From: Vitaly Bordug <[email-masked]>
Date: Mon, 23 Apr 2007 10:14:27 +0400

On Sun, 22 Apr 2007 23:49:41 +0200
Arnd Bergmann wrote:

> On Sunday 22 April 2007, Vitaly Bordug wrote:
> > This utilizes PCMCIA on mpc885ads and mpc866ads from arch/powerpc.
> > In the new approach, direct IMMR accesses from within drivers/ were
> > totally eliminated, that requires hardware_enable,
> > hardware_disable, voltage_set board-specific functions to be moved
> > over to BSP code section (arch/powerpc/platforms/8xx in 885 case).
> > There is just no way to have both arch/ppc and arch/powerpc
> > approaches to work simultaneously because of that.  
> 
> Maybe I'm missing a key issue here, but what's the point of adding
> more platform_devices for stuff that is already in the device tree?
> Shouldn't this be made an of_platform_driver instead so you can
> use the existing of_device directly?
> 
Was thinking of it but platform_device is better for migration purposes. Hence,
assuming somebody would want to have pcmcia working not bothering to add whole arch/powerpc support,
it can be accomplished quickly. OTOH, further change from pd to of_device is not hard as well. So far, most ppc stuff (if not all) still existing both in ppc/ and powerpc/ paths, and to keep consistency platform_devices are used here and there. So, with pd approach arch/ppc/ boards are encouraged to get source device/driver bus ready, hereby simplifying transition to of_device later.

With current bootwrapper activities it may happen sooner, but there are many places in kernel nobody want to move for almost zero value..

-- 
Sincerely, Vitaly