ASoC: fsl-asoc-card: Don't add DAPM routes for ASRC if it doesn't exist

There are a pair of warnings when ASRC is absent in the DTB:
  fsl-asoc-card sound: ASoC: no source widget found for ASRC-Playback
  fsl-asoc-card sound: ASoC: Failed to add route ASRC-Playback -> direct -> CPU-Playback
  fsl-asoc-card sound: ASoC: no sink widget found for ASRC-Capture
  fsl-asoc-card sound: ASoC: Failed to add route CPU-Capture -> direct -> ASRC-Capture

This is because the driver is still trying to add DAPM routes for ASRC
even if it doesn't exist on that platform.

The warnings are harmless but it might be annoying. So this patch drops
the DAPM routes of ASRC when it's absent in the DAI link.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/fsl/fsl-asoc-card.c

@@ -99,19 +99,26 @@ struct fsl_asoc_card_priv {
 /**
  * This dapm route map exsits for DPCM link only.
  * The other routes shall go through Device Tree.
+ *
+ * Note: keep all ASRC routes in the second half
+ *	 to drop them easily for non-ASRC cases.
  */
 static const struct snd_soc_dapm_route audio_map[] = {
-	{"CPU-Playback",  NULL, "ASRC-Playback"},
+	/* 1st half -- Normal DAPM routes */
 	{"Playback",  NULL, "CPU-Playback"},
-	{"ASRC-Capture",  NULL, "CPU-Capture"},
 	{"CPU-Capture",  NULL, "Capture"},
+	/* 2nd half -- ASRC DAPM routes */
+	{"CPU-Playback",  NULL, "ASRC-Playback"},
+	{"ASRC-Capture",  NULL, "CPU-Capture"},
 };
 
 static const struct snd_soc_dapm_route audio_map_ac97[] = {
-	{"AC97 Playback",  NULL, "ASRC-Playback"},
+	/* 1st half -- Normal DAPM routes */
 	{"Playback",  NULL, "AC97 Playback"},
-	{"ASRC-Capture",  NULL, "AC97 Capture"},
 	{"AC97 Capture",  NULL, "Capture"},
+	/* 2nd half -- ASRC DAPM routes */
+	{"AC97 Playback",  NULL, "ASRC-Playback"},
+	{"ASRC-Capture",  NULL, "AC97 Capture"},
 };
 
 /* Add all possible widgets into here without being redundant */
@@ -593,6 +600,10 @@ static int fsl_asoc_card_probe(struct platform_device *pdev)
 	priv->card.dapm_widgets = fsl_asoc_card_dapm_widgets;
 	priv->card.num_dapm_widgets = ARRAY_SIZE(fsl_asoc_card_dapm_widgets);
 
+	/* Drop the second half of DAPM routes -- ASRC */
+	if (!asrc_pdev)
+		priv->card.num_dapm_routes /= 2;
+
 	memcpy(priv->dai_link, fsl_asoc_card_dai,
 	       sizeof(struct snd_soc_dai_link) * ARRAY_SIZE(priv->dai_link));