Re: [PATCH V2] dma: tegra: register as an OF DMA controller

[Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>]

On 11/25/2013 04:09 PM, Dan Williams wrote:
> On Mon, Nov 25, 2013 at 2:30 PM, Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> wrote:
>> On 11/25/2013 03:09 PM, Arnd Bergmann wrote:
>>> On Monday 25 November 2013 14:53:36 Stephen Warren wrote:
>>>> v2: Use of_dma_slave_xlate() rather than of_dma_simple_xlate(), as
>>>>     suggested by Arnd Bergmann.
>>>>
>>>> This patch is part of a series with strong internal depdendencies. I'm
>>>> looking for an ack so that I can take the entire series through the Tegra
>>>> and arm-soc trees. The series will be part of a stable branch that can be
>>>> merged into other subsystems if needed to avoid/resolve dependencies.
>>>
>>> Did I suggest of_dma_slave_xlate()? I don't think I've actually heard
>>> of that function, and I can't find anything in the kernel source or
>>> using google.
>>>
>>> Why not just use an open-coded xlate function?
>>
>> Well, you suggested not using of_dma_simple_xlate() since it wasn't
>> appropriate. I then started to implement an open-coded xlate function,
>> but found that it was 99% identical to the same thing in the mmp driver,
>> and hence created a common of_dma_slave_xlate() so as not to just
>> cut/paste it everywhere. Unfortunately, I only sent that patch to
>> dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org and the DMA maintainers, and there's no
>> archive of that list:-(
> 
> There is, however, an archive of the patches:
> 
> dma: add common of_dma_slave_xlate()
> https://patchwork.kernel.org/patch/3234751/
> 
> dma: mmp_pdma: use of_dma_slave_xlate()
> https://patchwork.kernel.org/patch/3234761/

Ah, that's useful.

> ..btw I think we should squash those two together.

Isn't it more typical to do core work in one patch, then port each
driver individually? That keeps the patches small and logically
distinct, which could help bisect in some cases. But I guess I can go
either way.