static int snd_c400_create_vol_ctls(struct usb_mixer_interface *mixer)
{
	char name[64];
	unsigned int cmask, offset;
	int out, chan, err;
	int num_outs = 0;
	int num_ins = 0;

	const unsigned int id = 0x40;
	const int val_type = USB_MIXER_S16;
	const int control = 1;

	switch (mixer->chip->usb_id) {
	case USB_ID(0x0763, 0x2030):
		num_outs = 6;
		num_ins = 4;
		break;
	case USB_ID(0x0763, 0x2031):
		num_outs = 8;
		num_ins = 6;
		break;
	}

	for (chan = 0; chan < num_outs + num_ins; chan++) {
		for (out = 0; out < num_outs; out++) {
			if (chan < num_outs) {
				snprintf(name, sizeof(name),
					"PCM%d-Out%d Playback Volume",
					chan + 1, out + 1);
			} else {
				snprintf(name, sizeof(name),
					"In%d-Out%d Playback Volume",
					chan - num_outs + 1, out + 1);
			}

			cmask = (out == 0) ? 0 : 1 << (out - 1);
			offset = chan * num_outs;
			err = snd_create_std_mono_ctl_offset(mixer, id, control,
						cmask, val_type, offset, name,
						&snd_usb_mixer_vol_tlv);
			if (err < 0)
				return err;
		}
	}

	return 0;
}
static int snd_c400_create_vol_ctls(struct usb_mixer_interface *mixer)
{
	char name[64];
	unsigned int cmask, offset;
	int out, chan, err;
	int num_outs = 0;
	int num_ins = 0;

	const unsigned int id = 0x40;
	const int val_type = USB_MIXER_S16;
	const int control = 1;

	switch (mixer->chip->usb_id) {
	case USB_ID(0x0763, 0x2030):
		num_outs = 6;
		num_ins = 4;
		break;
	case USB_ID(0x0763, 0x2031):
		num_outs = 8;
		num_ins = 6;
		break;
	}

	for (chan = 0; chan < num_outs + num_ins; chan++) {
		for (out = 0; out < num_outs; out++) {
			if (chan < num_outs) {
				snprintf(name, sizeof(name),
					"PCM%d-Out%d Playback Volume",
					chan + 1, out + 1);
			} else {
				snprintf(name, sizeof(name),
					"In%d-Out%d Playback Volume",
					chan - num_outs + 1, out + 1);
			}

			cmask = (out == 0) ? 0 : 1 << (out - 1);
			offset = chan * num_outs;
			err = snd_create_std_mono_ctl_offset(mixer, id, control,
						cmask, val_type, offset, name,
						&snd_usb_mixer_vol_tlv);
			if (err < 0)
				return err;
		}
	}

	return 0;
}