On Thu, Mar 21, 2013 at 03:27:18PM +0530, Vinod Koul wrote:
On Fri, Mar 15, 2013 at 11:36:41AM +0800, 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.
Add a new API snd_dmaengine_generic_pcm_open() as the variant of snd_dmaengine_pcm_open(). It takes DMA client struct device pointer and slave channel name as arguments and calls generic DMA helper dma_request_slave_channel() to request DMA channel from dmaengine.
NAK
This is why we have dma_request_slave_channel_compat() API. You dont need to write two open handlers here, just pass all the arguments and if DT is set it will allocate a channel using dma_request_slave_channel() otherwise will do dma_request_channel which is what you need.
I do not quite follow your comment. Let me try to understand it. Are you suggesting that instead of the current call path:
snd_dmaengine_pcm_open() dmaengine_pcm_request_channel() dma_request_channel()
we should change it as below?
snd_dmaengine_pcm_open() dmaengine_pcm_request_channel() dma_request_slave_channel_compat()
If that's the case, you are fundamentally requesting to change the fingerprint of API snd_dmaengine_pcm_open() from the existing:
int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream, dma_filter_fn filter_fn, void *filter_data)
to something like:
int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream, dma_filter_fn filter_fn, void *filter_data, struct device *dev, const char *name)
So every single user of snd_dmaengine_pcm_open() needs to adapt to the interface change.
Is my understanding correct? Or have I misunderstood your comment?
Shawn