ASoC: soc-dai: add get_sdw_stream() callback

We only have a set() operation, provide the dual get() operation to
retrieve the stream information.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200225170041.23644-3-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

include/sound/soc-dai.h

@@ -202,6 +202,8 @@ struct snd_soc_dai_ops {
 
 	int (*set_sdw_stream)(struct snd_soc_dai *dai,
 			void *stream, int direction);
+	void *(*get_sdw_stream)(struct snd_soc_dai *dai, int direction);
+
 	/*
 	 * DAI digital mute - optional.
 	 * Called by soc-core to minimise any pops.
@@ -423,4 +425,23 @@ static inline int snd_soc_dai_set_sdw_stream(struct snd_soc_dai *dai,
 		return -ENOTSUPP;
 }
 
+/**
+ * snd_soc_dai_get_sdw_stream() - Retrieves SDW stream from DAI
+ * @dai: DAI
+ * @direction: Stream direction(Playback/Capture)
+ *
+ * This routine only retrieves that was previously configured
+ * with snd_soc_dai_get_sdw_stream()
+ *
+ * Returns pointer to stream or NULL;
+ */
+static inline void *snd_soc_dai_get_sdw_stream(struct snd_soc_dai *dai,
+					       int direction)
+{
+	if (dai->driver->ops->get_sdw_stream)
+		return dai->driver->ops->get_sdw_stream(dai, direction);
+	else
+		return NULL;
+}
+
 #endif