ASoC: simple-card: add asoc_simple_card_get_conversion()

simple-card is now supporting normal sound and DPCM sound.
For DPCM sound, original sound card (= simple-scu-card) had been
supported 1 CPU : 1 Codec connection which uses hw_params_fixup()
for convert-rate/channel.
But, merged simple-card is completely forgeting about it.

To re-support 1 CPU : 1 Codec DPCM for hw_params_fixup(),
it need to judge whether it is DPCM by checking convert-rate/channel.
For this purpose, this patch adds asoc_simple_card_get_conversion()
as preparation

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/generic/simple-card.c

@@ -165,6 +165,21 @@ static int asoc_simple_card_be_hw_params_fixup(struct snd_soc_pcm_runtime *rtd,
 	return 0;
 }
 
+static void asoc_simple_card_get_conversion(struct device *dev,
+					    struct device_node *np,
+					    struct asoc_simple_card_data *adata)
+{
+	struct device_node *top = dev->of_node;
+	struct device_node *node = of_get_parent(np);
+
+	asoc_simple_card_parse_convert(dev, top,  PREFIX, adata);
+	asoc_simple_card_parse_convert(dev, node, PREFIX, adata);
+	asoc_simple_card_parse_convert(dev, node, NULL,   adata);
+	asoc_simple_card_parse_convert(dev, np,   NULL,   adata);
+
+	of_node_put(node);
+}
+
 static int asoc_simple_card_dai_link_of_dpcm(struct device_node *top,
 					     struct device_node *node,
 					     struct device_node *np,
@@ -260,9 +275,7 @@ static int asoc_simple_card_dai_link_of_dpcm(struct device_node *top,
 					     "prefix");
 	}
 
-	asoc_simple_card_parse_convert(dev, top,  PREFIX, &dai_props->adata);
-	asoc_simple_card_parse_convert(dev, node, prefix, &dai_props->adata);
-	asoc_simple_card_parse_convert(dev, np,   NULL,   &dai_props->adata);
+	asoc_simple_card_get_conversion(dev, np, &dai_props->adata);
 
 	ret = asoc_simple_card_of_parse_tdm(np, dai);
 	if (ret)