Liam,
In order to get fsl_dma.c to work with the WM8776, which has separate DAIs for playback and capture, I've had to do this:
if (pcm->streams[0].substream) { ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, card->dev, fsl_dma_hardware.buffer_bytes_max, &pcm->streams[0].substream->dma_buffer); if (ret) { dev_err(card->dev, "can't allocate playback dma buffer\n"); return ret; } }
if (pcm->streams[1].substream) { ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, card->dev, fsl_dma_hardware.buffer_bytes_max, &pcm->streams[1].substream->dma_buffer); if (ret) { snd_dma_free_pages(&pcm->streams[0].substream->dma_buffer); dev_err(card->dev, "can't allocate capture dma buffer\n"); return ret; } }
That is, I need to check if the 'substream' pointer has been initialized.
This looks ugly to me. In an earlier version of ASoC, I would have done this:
if (dai->playback.channels_min) { ...
if (dai->capture.channels_min) { ...
But dai->playback and dai->capture no longer exist. How should I handle this?