ASoC: core: Flip master for CODECs in the CPU slot of a CODEC<->CODEC link

When two CODEC DAIs are linked directly to each other then if we give the
same master mode settings to both devices things won't work as either
neither will drive or they'll drive against each other. Flip the settings
for the DAI in the CPU slot of the DAI link.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/soc-core.c

@@ -1416,7 +1416,7 @@ static int snd_soc_instantiate_card(struct snd_soc_card *card)
 	struct snd_soc_codec_conf *codec_conf;
 	enum snd_soc_compress_type compress_type;
 	struct snd_soc_dai_link *dai_link;
-	int ret, i, order;
+	int ret, i, order, dai_fmt;
 
 	mutex_lock_nested(&card->mutex, SND_SOC_CARD_CLASS_INIT);
 
@@ -1525,17 +1525,46 @@ static int snd_soc_instantiate_card(struct snd_soc_card *card)
 
 	for (i = 0; i < card->num_links; i++) {
 		dai_link = &card->dai_link[i];
+		dai_fmt = dai_link->dai_fmt;
 
-		if (dai_link->dai_fmt) {
+		if (dai_fmt) {
 			ret = snd_soc_dai_set_fmt(card->rtd[i].codec_dai,
-						  dai_link->dai_fmt);
+						  dai_fmt);
 			if (ret != 0 && ret != -ENOTSUPP)
 				dev_warn(card->rtd[i].codec_dai->dev,
 					 "Failed to set DAI format: %d\n",
 					 ret);
+		}
+
+		/* If this is a regular CPU link there will be a platform */
+		if (dai_fmt && dai_link->platform_name) {
+			ret = snd_soc_dai_set_fmt(card->rtd[i].cpu_dai,
+						  dai_fmt);
+			if (ret != 0 && ret != -ENOTSUPP)
+				dev_warn(card->rtd[i].cpu_dai->dev,
+					 "Failed to set DAI format: %d\n",
+					 ret);
+		} else if (dai_fmt) {
+			/* Flip the polarity for the "CPU" end */
+			dai_fmt &= ~SND_SOC_DAIFMT_MASTER_MASK;
+			switch (dai_link->dai_fmt &
+				SND_SOC_DAIFMT_MASTER_MASK) {
+			case SND_SOC_DAIFMT_CBM_CFM:
+				dai_fmt |= SND_SOC_DAIFMT_CBS_CFS;
+				break;
+			case SND_SOC_DAIFMT_CBM_CFS:
+				dai_fmt |= SND_SOC_DAIFMT_CBS_CFM;
+				break;
+			case SND_SOC_DAIFMT_CBS_CFM:
+				dai_fmt |= SND_SOC_DAIFMT_CBM_CFS;
+				break;
+			case SND_SOC_DAIFMT_CBS_CFS:
+				dai_fmt |= SND_SOC_DAIFMT_CBM_CFM;
+				break;
+			}
 
 			ret = snd_soc_dai_set_fmt(card->rtd[i].cpu_dai,
-						  dai_link->dai_fmt);
+						  dai_fmt);
 			if (ret != 0 && ret != -ENOTSUPP)
 				dev_warn(card->rtd[i].cpu_dai->dev,
 					 "Failed to set DAI format: %d\n",