ASoC: Intel: sof_sdw: Add a DAI link for echo reference

Add a DAI link for echo reference capture as the last link to make sure
the other DAI link ID's remain unaffected. This will be needed to enable
the echo reference capture in the SDW topologies which do not have a
backend capture DAI in the pipeline.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

Author: ranj063

sound/soc/intel/boards/sof_sdw.c

@@ -1196,6 +1196,28 @@ static int create_bt_dailinks(struct snd_soc_card *card,
 	return 0;
 }
 
+static int create_echoref_dailink(struct snd_soc_card *card,
+				  struct snd_soc_dai_link **dai_links, int *be_id)
+{
+	struct device *dev = card->dev;
+	int ret;
+	char *name = devm_kasprintf(dev, GFP_KERNEL, "EchoRef_virtual_DAI");
+
+	if (!name)
+		return -ENOMEM;
+
+	ret = asoc_sdw_init_simple_dai_link(dev, *dai_links, be_id, name,
+			0, 1, "snd-soc-dummy-dai", "dummy",
+			snd_soc_dummy_dlc.name, snd_soc_dummy_dlc.dai_name,
+			1, NULL, NULL);
+	if (ret)
+		return ret;
+
+	(*dai_links)++;
+
+	return 0;
+}
+
 static int sof_card_dai_links_create(struct snd_soc_card *card)
 {
 	struct device *dev = card->dev;
@@ -1294,7 +1316,7 @@ static int sof_card_dai_links_create(struct snd_soc_card *card)
 	}
 
 	/* allocate BE dailinks */
-	num_links = sdw_be_num + ssp_num + dmic_num + hdmi_num + bt_num;
+	num_links = sdw_be_num + ssp_num + dmic_num + hdmi_num + bt_num + 1;
 	dai_links = devm_kcalloc(dev, num_links, sizeof(*dai_links), GFP_KERNEL);
 	if (!dai_links) {
 		ret = -ENOMEM;
@@ -1341,6 +1363,13 @@ static int sof_card_dai_links_create(struct snd_soc_card *card)
 			goto err_end;
 	}
 
+	/* dummy echo ref link */
+	ret = create_echoref_dailink(card, &dai_links, &be_id);
+	if (ret) {
+		dev_err(dev, "failed to create echo ref dai link: %d\n", ret);
+		goto err_end;
+	}
+
 	WARN_ON(codec_conf != card->codec_conf + card->num_configs);
 	WARN_ON(dai_links != card->dai_link + card->num_links);