[PATCH v26 15/33] ASoC: usb: Fetch ASoC card and pcm device information

[Wesley Cheng <quic_wcheng@xxxxxxxxxxx>]

USB SND needs to know how the USB offload path is being routed.  This would
allow for applications to open the corresponding sound card and pcm device
when it wants to take the audio offload path.  This callback should return
the mapped indexes based on the USB SND device information.

Signed-off-by: Wesley Cheng <quic_wcheng@xxxxxxxxxxx>
---
 include/sound/soc-usb.h | 12 ++++++++++++
 sound/soc/soc-usb.c     | 31 +++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/include/sound/soc-usb.h b/include/sound/soc-usb.h
index 5c788cbfa82e..86876098a2b7 100644
--- a/include/sound/soc-usb.h
+++ b/include/sound/soc-usb.h
@@ -36,6 +36,7 @@ struct snd_soc_usb_device {
  * @list - list head for SND SOC struct list
  * @component - reference to ASoC component
  * @connection_status_cb - callback to notify connection events
+ * @update_offload_route_info - callback to fetch mapped ASoC device
  * @priv_data - driver data
  **/
 struct snd_soc_usb {
@@ -44,6 +45,9 @@ struct snd_soc_usb {
 	int (*connection_status_cb)(struct snd_soc_usb *usb,
 				    struct snd_soc_usb_device *sdev,
 				    bool connected);
+	int (*update_offload_route_info)(struct snd_soc_component *component,
+					 int card, int pcm, int direction,
+					 long *route);
 	void *priv_data;
 };
 
@@ -59,6 +63,8 @@ void *snd_soc_usb_find_priv_data(struct device *dev);
 int snd_soc_usb_setup_offload_jack(struct snd_soc_component *component,
 				   struct snd_soc_jack *jack);
 int snd_soc_usb_disable_offload_jack(struct snd_soc_component *component);
+int snd_soc_usb_update_offload_route(struct device *dev, int card, int pcm,
+				     int direction, long *route);
 
 struct snd_soc_usb *snd_soc_usb_allocate_port(struct snd_soc_component *component,
 					      void *data);
@@ -101,6 +107,12 @@ static inline int snd_soc_usb_disable_offload_jack(struct snd_soc_component *com
 	return 0;
 }
 
+static int snd_soc_usb_update_offload_route(struct device *dev, int card, int pcm,
+					    int direction, long *route)
+{
+	return -ENODEV;
+}
+
 static inline struct snd_soc_usb *
 snd_soc_usb_allocate_port(struct snd_soc_component *component, void *data)
 {
diff --git a/sound/soc/soc-usb.c b/sound/soc/soc-usb.c
index 3d5354298206..de249e8a28cb 100644
--- a/sound/soc/soc-usb.c
+++ b/sound/soc/soc-usb.c
@@ -117,6 +117,37 @@ int snd_soc_usb_disable_offload_jack(struct snd_soc_component *component)
 }
 EXPORT_SYMBOL_GPL(snd_soc_usb_disable_offload_jack);
 
+/**
+ * snd_soc_usb_update_offload_route - Find active USB offload path
+ * @dev - USB device to get offload status
+ * @card - USB card index
+ * @pcm - USB PCM device index
+ * @direction - playback or capture direction
+ * @route - pointer to route output array
+ *
+ * Fetch the current status for the USB SND card and PCM device indexes
+ * specified.
+ */
+int snd_soc_usb_update_offload_route(struct device *dev, int card, int pcm,
+				     int direction, long *route)
+{
+	struct snd_soc_usb *ctx;
+	int ret;
+
+	ctx = snd_soc_find_usb_ctx(dev);
+	if (!ctx)
+		return -ENODEV;
+
+	mutex_lock(&ctx_mutex);
+	if (ctx && ctx->update_offload_route_info)
+		ret = ctx->update_offload_route_info(ctx->component, card, pcm,
+						     direction, route);
+	mutex_unlock(&ctx_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_update_offload_route);
+
 /**
  * snd_soc_usb_find_priv_data() - Retrieve private data stored
  * @dev: device reference