[alsa-devel] [PATCH v5] sound/soc/lapis: add platform driver for ML7213

Tomoya MORINAGA tomoya.rohm at gmail.com
Wed May 30 12:50:28 CEST 2012

On Mon, May 28, 2012 at 7:19 AM, Mark Brown
<broonie at opensource.wolfsonmicro.com> wrote:
>> > I'm not so familiar with Linux's DMA idea.
>> > So we don't know whether non-cyclic dmaengine has problem or not.
> Nobody has written the code, this is the problem!  If the code is not
> there, you should try to write it.  If there is some great problem
> writing the code then you should t

The latter of the above seems dropped...

>> First you should not be writing your own dma driver, it *needs* to use
>> dmaenegine. We already have bunch of driver supported, so there may be a
> He's already done that, their current code is all open coded dmaengine
> stuff.

I don't understand why you say so ?
I don't use any own dma driver, right ? I use only dmaengine's.
If there is own, let me show.

>> > As you said, common code for DMA code can be best solution.
>> > However, currently, the code is nothing.
>> > So, I want you to accept our driver as first step.
>> > Because I think supporting new device is more important for linux than
>> > dmaengine common.
> The existing code is far from nothing, there is a fairly substantial
> dmaengine library there already which should share a big chunk of code
> with any cyclic support.  If you were saying "this is too hard for
> $REASON" that'd be one thing but that's not what you're saying here.

If our ASoC supports cyclic dma mode, we must modify both pch_dma
driver and our ASoC driver.
I don't want to do this.
Because I can't understand the merit. In plain words, to me, this
looks insignificant things.
In fact, current all applied ASoC drivers use dmaengine don't use
cyclic mode, right ?

> It's possible that there is actually some substantial difficult but
> my first instinct would be that it should be relatively straightforward.

Let me clarify your saying again.
Which do you want ?
  1) pch_dma must support cyclic dma mode and our ASoC driver must use
the cyclic dma function.
  2) Non-cyclic dma engine should be added to alsa-dmaengine by myself.
  3) Other


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