int g_audio_setup()

in gadget/function/u_audio.c [978:1213]
182 lines of code
36 McCabe index (conditional complexity)

int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
					const char *card_name)
{
	struct snd_uac_chip *uac;
	struct snd_card *card;
	struct snd_pcm *pcm;
	struct snd_kcontrol *kctl;
	struct uac_params *params;
	int p_chmask, c_chmask;
	int i, err;

	if (!g_audio)
		return -EINVAL;

	uac = kzalloc(sizeof(*uac), GFP_KERNEL);
	if (!uac)
		return -ENOMEM;
	g_audio->uac = uac;
	uac->audio_dev = g_audio;

	params = &g_audio->params;
	p_chmask = params->p_chmask;
	c_chmask = params->c_chmask;

	if (c_chmask) {
		struct uac_rtd_params *prm = &uac->c_prm;

    spin_lock_init(&prm->lock);
    uac->c_prm.uac = uac;
		prm->max_psize = g_audio->out_ep_maxpsize;

		prm->reqs = kcalloc(params->req_number,
				    sizeof(struct usb_request *),
				    GFP_KERNEL);
		if (!prm->reqs) {
			err = -ENOMEM;
			goto fail;
		}

		prm->rbuf = kcalloc(params->req_number, prm->max_psize,
				GFP_KERNEL);
		if (!prm->rbuf) {
			prm->max_psize = 0;
			err = -ENOMEM;
			goto fail;
		}
	}

	if (p_chmask) {
		struct uac_rtd_params *prm = &uac->p_prm;

		spin_lock_init(&prm->lock);
		uac->p_prm.uac = uac;
		prm->max_psize = g_audio->in_ep_maxpsize;

		prm->reqs = kcalloc(params->req_number,
				    sizeof(struct usb_request *),
				    GFP_KERNEL);
		if (!prm->reqs) {
			err = -ENOMEM;
			goto fail;
		}

		prm->rbuf = kcalloc(params->req_number, prm->max_psize,
				GFP_KERNEL);
		if (!prm->rbuf) {
			prm->max_psize = 0;
			err = -ENOMEM;
			goto fail;
		}
	}

	/* Choose any slot, with no id */
	err = snd_card_new(&g_audio->gadget->dev,
			-1, NULL, THIS_MODULE, 0, &card);
	if (err < 0)
		goto fail;

	uac->card = card;

	/*
	 * Create first PCM device
	 * Create a substream only for non-zero channel streams
	 */
	err = snd_pcm_new(uac->card, pcm_name, 0,
			       p_chmask ? 1 : 0, c_chmask ? 1 : 0, &pcm);
	if (err < 0)
		goto snd_fail;

	strscpy(pcm->name, pcm_name, sizeof(pcm->name));
	pcm->private_data = uac;
	uac->pcm = pcm;

	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &uac_pcm_ops);
	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &uac_pcm_ops);

	/*
	 * Create mixer and controls
	 * Create only if it's required on USB side
	 */
	if ((c_chmask && g_audio->in_ep_fback)
			|| (p_chmask && params->p_fu.id)
			|| (c_chmask && params->c_fu.id))
		strscpy(card->mixername, card_name, sizeof(card->driver));

	if (c_chmask && g_audio->in_ep_fback) {
		kctl = snd_ctl_new1(&u_audio_controls[UAC_FBACK_CTRL],
				    &uac->c_prm);
		if (!kctl) {
			err = -ENOMEM;
			goto snd_fail;
		}

		kctl->id.device = pcm->device;
		kctl->id.subdevice = 0;

		err = snd_ctl_add(card, kctl);
		if (err < 0)
			goto snd_fail;
	}

	if (p_chmask) {
		kctl = snd_ctl_new1(&u_audio_controls[UAC_P_PITCH_CTRL],
				    &uac->p_prm);
		if (!kctl) {
			err = -ENOMEM;
			goto snd_fail;
		}

		kctl->id.device = pcm->device;
		kctl->id.subdevice = 0;

		err = snd_ctl_add(card, kctl);
		if (err < 0)
			goto snd_fail;
	}

	for (i = 0; i <= SNDRV_PCM_STREAM_LAST; i++) {
		struct uac_rtd_params *prm;
		struct uac_fu_params *fu;
		char ctrl_name[24];
		char *direction;

		if (!pcm->streams[i].substream_count)
			continue;

		if (i == SNDRV_PCM_STREAM_PLAYBACK) {
			prm = &uac->p_prm;
			fu = &params->p_fu;
			direction = "Playback";
		} else {
			prm = &uac->c_prm;
			fu = &params->c_fu;
			direction = "Capture";
		}

		prm->fu_id = fu->id;

		if (fu->mute_present) {
			snprintf(ctrl_name, sizeof(ctrl_name),
					"PCM %s Switch", direction);

			u_audio_controls[UAC_MUTE_CTRL].name = ctrl_name;

			kctl = snd_ctl_new1(&u_audio_controls[UAC_MUTE_CTRL],
					    prm);
			if (!kctl) {
				err = -ENOMEM;
				goto snd_fail;
			}

			kctl->id.device = pcm->device;
			kctl->id.subdevice = 0;

			err = snd_ctl_add(card, kctl);
			if (err < 0)
				goto snd_fail;
			prm->snd_kctl_mute = kctl;
			prm->mute = 0;
		}

		if (fu->volume_present) {
			snprintf(ctrl_name, sizeof(ctrl_name),
					"PCM %s Volume", direction);

			u_audio_controls[UAC_VOLUME_CTRL].name = ctrl_name;

			kctl = snd_ctl_new1(&u_audio_controls[UAC_VOLUME_CTRL],
					    prm);
			if (!kctl) {
				err = -ENOMEM;
				goto snd_fail;
			}

			kctl->id.device = pcm->device;
			kctl->id.subdevice = 0;


			kctl->tlv.c = u_audio_volume_tlv;
			kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ |
					SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;

			err = snd_ctl_add(card, kctl);
			if (err < 0)
				goto snd_fail;
			prm->snd_kctl_volume = kctl;
			prm->volume = fu->volume_max;
			prm->volume_max = fu->volume_max;
			prm->volume_min = fu->volume_min;
			prm->volume_res = fu->volume_res;
		}
	}

	strscpy(card->driver, card_name, sizeof(card->driver));
	strscpy(card->shortname, card_name, sizeof(card->shortname));
	sprintf(card->longname, "%s %i", card_name, card->dev->id);

	snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
				       NULL, 0, BUFF_SIZE_MAX);

	err = snd_card_register(card);

	if (!err)
		return 0;

snd_fail:
	snd_card_free(card);
fail:
	kfree(uac->p_prm.reqs);
	kfree(uac->c_prm.reqs);
	kfree(uac->p_prm.rbuf);
	kfree(uac->c_prm.rbuf);
	kfree(uac);

	return err;
}