Re: [PATCH 1/7] mmc: mxs-mmc: add mmc host driver for i.MX23/28

Shawn Guo
2011-02-12T10:39:21Z

On Sat, Feb 12, 2011 at 11:07:17AM +0100, Arnd Bergmann wrote:
> On Saturday 12 February 2011 18:23:58 Shawn Guo wrote:
> > Well, we are removing inclusion of mach/dma.h from mmc driver, but
> > adding it to every mxs based machine code. This makes mmc driver
> > clean but machine code becomes not. For some dma client devices
> > coming later, the platform data could be saved at all, if they do not
> > have any. But with the approach you are suggesting, every single
> > client device will have to get platform data.
>
> Right, unless there is a way to encode it exlusively in the resources,
> which is what I was suggesting at first: If the dma engine driver
> knows about all the channels, you only need to pass the channel number.
>
> If you use a flattened device tree, you can avoid the need for
> platform data by adding the phandle of the dma engine device to
> a property of the mmc driver, along with the channel number inside
> of that device. I think that would be the cleanest approach, but
> some people still need to be convinced that changing drivers to
> use fdt data is the right direction for ARM.
>
Could we keep the current the approach for now and go to the cleanest
way directly when Grant's dt patches get merged?

Regards,
Shawn