ASoC: minor cleanup for soc_get_playback_capture()

Merge series from Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>:

This is minor cleanup patches for soc_get_playback_capture().

sound/soc/soc-pcm.c

@@ -2730,48 +2730,50 @@ static int dpcm_fe_dai_open(struct snd_pcm_substream *fe_substream)
 static int soc_get_playback_capture(struct snd_soc_pcm_runtime *rtd,
 				    int *playback, int *capture)
 {
+	struct snd_soc_dai_link *dai_link = rtd->dai_link;
 	struct snd_soc_dai *cpu_dai;
+	int has_playback = 0;
+	int has_capture  = 0;
 	int i;
 
-	if (rtd->dai_link->dynamic && rtd->dai_link->num_cpus > 1) {
-		dev_err(rtd->dev,
-			"DPCM doesn't support Multi CPU for Front-Ends yet\n");
+	if (dai_link->dynamic && dai_link->num_cpus > 1) {
+		dev_err(rtd->dev, "DPCM doesn't support Multi CPU for Front-Ends yet\n");
 		return -EINVAL;
 	}
 
-	if (rtd->dai_link->dynamic || rtd->dai_link->no_pcm) {
+	if (dai_link->dynamic || dai_link->no_pcm) {
 		int stream;
 
-		if (rtd->dai_link->dpcm_playback) {
+		if (dai_link->dpcm_playback) {
 			stream = SNDRV_PCM_STREAM_PLAYBACK;
 
 			for_each_rtd_cpu_dais(rtd, i, cpu_dai) {
 				if (snd_soc_dai_stream_valid(cpu_dai, stream)) {
-					*playback = 1;
+					has_playback = 1;
 					break;
 				}
 			}
-			if (!*playback) {
+			if (!has_playback) {
 				dev_err(rtd->card->dev,
 					"No CPU DAIs support playback for stream %s\n",
-					rtd->dai_link->stream_name);
+					dai_link->stream_name);
 				return -EINVAL;
 			}
 		}
-		if (rtd->dai_link->dpcm_capture) {
+		if (dai_link->dpcm_capture) {
 			stream = SNDRV_PCM_STREAM_CAPTURE;
 
 			for_each_rtd_cpu_dais(rtd, i, cpu_dai) {
 				if (snd_soc_dai_stream_valid(cpu_dai, stream)) {
-					*capture = 1;
+					has_capture = 1;
 					break;
 				}
 			}
 
-			if (!*capture) {
+			if (!has_capture) {
 				dev_err(rtd->card->dev,
 					"No CPU DAIs support capture for stream %s\n",
-					rtd->dai_link->stream_name);
+					dai_link->stream_name);
 				return -EINVAL;
 			}
 		}
@@ -2779,15 +2781,15 @@ static int soc_get_playback_capture(struct snd_soc_pcm_runtime *rtd,
 		struct snd_soc_dai *codec_dai;
 
 		/* Adapt stream for codec2codec links */
-		int cpu_capture = rtd->dai_link->c2c_params ?
+		int cpu_capture = dai_link->c2c_params ?
 			SNDRV_PCM_STREAM_PLAYBACK : SNDRV_PCM_STREAM_CAPTURE;
-		int cpu_playback = rtd->dai_link->c2c_params ?
+		int cpu_playback = dai_link->c2c_params ?
 			SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
 
 		for_each_rtd_codec_dais(rtd, i, codec_dai) {
-			if (rtd->dai_link->num_cpus == 1) {
+			if (dai_link->num_cpus == 1) {
 				cpu_dai = asoc_rtd_to_cpu(rtd, 0);
-			} else if (rtd->dai_link->num_cpus == rtd->dai_link->num_codecs) {
+			} else if (dai_link->num_cpus == dai_link->num_codecs) {
 				cpu_dai = asoc_rtd_to_cpu(rtd, i);
 			} else {
 				dev_err(rtd->card->dev,
@@ -2797,23 +2799,29 @@ static int soc_get_playback_capture(struct snd_soc_pcm_runtime *rtd,
 
 			if (snd_soc_dai_stream_valid(codec_dai, SNDRV_PCM_STREAM_PLAYBACK) &&
 			    snd_soc_dai_stream_valid(cpu_dai,   cpu_playback))
-				*playback = 1;
+				has_playback = 1;
 			if (snd_soc_dai_stream_valid(codec_dai, SNDRV_PCM_STREAM_CAPTURE) &&
 			    snd_soc_dai_stream_valid(cpu_dai,   cpu_capture))
-				*capture = 1;
+				has_capture = 1;
 		}
 	}
 
-	if (rtd->dai_link->playback_only) {
-		*playback = 1;
-		*capture = 0;
-	}
+	if (dai_link->playback_only)
+		has_capture = 0;
 
-	if (rtd->dai_link->capture_only) {
-		*playback = 0;
-		*capture = 1;
+	if (dai_link->capture_only)
+		has_playback = 0;
+
+	if (!has_playback && !has_capture) {
+		dev_err(rtd->dev, "substream %s has no playback, no capture\n",
+			dai_link->stream_name);
+
+		return -EINVAL;
 	}
 
+	*playback = has_playback;
+	*capture  = has_capture;
+
 	return 0;
 }