snd_pcm_new_stream
int snd_pcm_new_stream(struct snd_pcm *pcm, int stream, int substream_count);
err = snd_pcm_new_stream(dev->pcm, SNDRV_PCM_STREAM_PLAYBACK, 1);
err = snd_pcm_new_stream(dev->pcm, SNDRV_PCM_STREAM_CAPTURE, 1);
EXPORT_SYMBOL(snd_pcm_new_stream);
err = snd_pcm_new_stream(pcm, SNDRV_PCM_STREAM_PLAYBACK,
err = snd_pcm_new_stream(pcm, SNDRV_PCM_STREAM_CAPTURE, capture_count);
err = snd_pcm_new_stream(as->pcm, stream, 1);