ASoC: dapm - Add methods to retrieve snd_card and soc_card from dapm context.

In preparation for ASoC Dynamic PCM (AKA DSP) support.

Provide convenience methods to retrieve the soc_card or snd_card from a
DAPM context.
Signed-off-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/soc-dapm.c

@@ -124,6 +124,36 @@ static inline struct snd_soc_dapm_widget *dapm_cnew_widget(
 	return kmemdup(_widget, sizeof(*_widget), GFP_KERNEL);
 }
 
+/* get snd_card from DAPM context */
+static inline struct snd_card *dapm_get_snd_card(
+	struct snd_soc_dapm_context *dapm)
+{
+	if (dapm->codec)
+		return dapm->codec->card->snd_card;
+	else if (dapm->platform)
+		return dapm->platform->card->snd_card;
+	else
+		BUG();
+
+	/* unreachable */
+	return NULL;
+}
+
+/* get soc_card from DAPM context */
+static inline struct snd_soc_card *dapm_get_soc_card(
+		struct snd_soc_dapm_context *dapm)
+{
+	if (dapm->codec)
+		return dapm->codec->card;
+	else if (dapm->platform)
+		return dapm->platform->card;
+	else
+		BUG();
+
+	/* unreachable */
+	return NULL;
+}
+
 static int soc_widget_read(struct snd_soc_dapm_widget *w, int reg)
 {
 	if (w->codec)