参照元

説明

引数

返り値

参考

実装

/**
 * snd_pcm_new - create a new PCM instance
 * @card: the card instance
 * @id: the id string
 * @device: the device index (zero based)
 * @playback_count: the number of substreams for playback
 * @capture_count: the number of substreams for capture
 * @rpcm: the pointer to store the new pcm instance
 *
 * Creates a new PCM instance.
 *
 * The pcm operators have to be set afterwards to the new instance
 * via snd_pcm_set_ops().
 *
 * Returns zero if successful, or a negative error code on failure.
 */
int snd_pcm_new(struct snd_card *card, const char *id, int device,
		int playback_count, int capture_count,
	        struct snd_pcm ** rpcm)
{
	struct snd_pcm *pcm;
	int err;
	static struct snd_device_ops ops = {
		.dev_free = snd_pcm_dev_free,
		.dev_register =	snd_pcm_dev_register,
		.dev_disconnect = snd_pcm_dev_disconnect,
	};
	if (snd_BUG_ON(!card))
		return -ENXIO;
	if (rpcm)
		*rpcm = NULL;
	pcm = kzalloc(sizeof(*pcm), GFP_KERNEL);
	if (pcm == NULL) {
		snd_printk(KERN_ERR "Cannot allocate PCM\n");
		return -ENOMEM;
	}
	pcm->card = card;
	pcm->device = device;
	if (id)
		strlcpy(pcm->id, id, sizeof(pcm->id));
	if ((err = snd_pcm_new_stream(pcm, SNDRV_PCM_STREAM_PLAYBACK, playback_count)) < 0) {
		snd_pcm_free(pcm);
		return err;
	}
	if ((err = snd_pcm_new_stream(pcm, SNDRV_PCM_STREAM_CAPTURE, capture_count)) < 0) {
		snd_pcm_free(pcm);
		return err;
	}
	mutex_init(&pcm->open_mutex);
	init_waitqueue_head(&pcm->open_wait);
	if ((err = snd_device_new(card, SNDRV_DEV_PCM, pcm, &ops)) < 0) {
		snd_pcm_free(pcm);
		return err;
	}
	if (rpcm)
		*rpcm = pcm;
	return 0;
}

EXPORT_SYMBOL(snd_pcm_new);

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Last-modified: 2014-09-13 (土) 08:26:43