[alsa-devel] [PATCH 09/12] ASoC: dmaengine_pcm: support use of generic DMA helper

Arnd Bergmann arnd at arndb.de
Wed Feb 27 22:02:40 CET 2013

On Wednesday 27 February 2013, Shawn Guo wrote:
> With generic DMA device tree binding and helper function
> dma_request_slave_channel() in place, dmaengine_pcm should support
> that in requesting DMA channel for users that support generic DMA
> device tree binding.
> Instead of inventing a new API, it defines the parameters needed by
> dma_request_slave_channel() into struct snd_dma_channel_params,
> interprets filter_data into snd_dma_channel_params, and calls the
> helper in case that dmaengine_pcm users pass in a NULL filter_fn.
> Then, dmaengine_pcm users can call snd_dmaengine_pcm_open() with NULL
> filter_fn and snd_dma_channel_params being filter_data to direct the
> API to request DMA channel using generic DMA helper.
> Signed-off-by: Shawn Guo <shawn.guo at linaro.org>
> Cc: Mark Brown <broonie at opensource.wolfsonmicro.com>
> Cc: alsa-devel at alsa-project.org

I would actually prefer having a new API in the soc-dmaengine-pcm
module, like

static int dmaengine_pcm_request_slave_channel(struct dmaengine_pcm_runtime_data *prtd,
						struct device *dev, const char *id);

For sound drivers that are fully converted to using DT, it would be
a more natural interface to use IMHO.

Your patch looks technically correct though, so it's up to Mark to decide
what he prefers.


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