audiomixer: Add gain controls

- Add Equalizer gain controls.
- Add a simple app to test the controls.

Bug-AGL: SPEC-4931
Change-Id: Ib33eb0e829747c401861e99acd67291462ec6a97
Signed-off-by: Ashok Sidipotu <ashok.sidipotu@collabora.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/audiomixer.h b/src/audiomixer.h
index cc67a83..2e50420 100644
--- a/src/audiomixer.h
+++ b/src/audiomixer.h
@@ -20,6 +20,7 @@ struct mixer_control
 {
 	char name[32];
 	double volume;
+	float gain;
 	bool mute;
 };
 
@@ -30,6 +31,7 @@ struct audiomixer_events
 	void (*value_changed) (void *data,
 #define MIXER_CONTROL_CHANGE_FLAG_VOLUME (1<<0)
 #define MIXER_CONTROL_CHANGE_FLAG_MUTE   (1<<1)
+#define MIXER_CONTROL_CHANGE_FLAG_GAIN (1<<2)
 				unsigned int change_mask,
 				const struct mixer_control *control);
 };
@@ -60,6 +62,10 @@ void audiomixer_change_volume(struct audiomixer *self,
 	const struct mixer_control *control,
 	double volume);
 
+void audiomixer_change_gain(struct audiomixer *self,
+	const struct mixer_control *control,
+	float gain);
+
 void audiomixer_change_mute(struct audiomixer *self,
 	const struct mixer_control *control,
 	bool mute);