Implement universal in-PCM-driver software volume control.

Implements double-buffered volume, balance and prescaling control in
the main PCM driver when HAVE_SW_VOLUME_CONTROL is defined ensuring
that all PCM is volume controlled and level changes are low in latency.

Supports -73 to +6 dB using a 15-bit factor so that no large-integer
math is needed.

Low-level hardware drivers do not have to implement it themselves but
parameters can be changed (currently defined in pcm-internal.h) to work
best with a particular SoC or to provide different volume ranges.

Volume and prescale calls should be made in the codec driver. It should
appear as a normal hardware interface. PCM volume calls expect .1 dB
units.

Change-Id: Idf6316a64ef4fb8abcede10707e1e6c6d01d57db
Reviewed-on: http://gerrit.rockbox.org/423
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Tested-by: Michael Sevakis <jethead71@rockbox.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/firmware/export/jz4740-codec.h b/firmware/export/jz4740-codec.h
index 37d2347f5b..3c088f5bf7 100644
--- a/firmware/export/jz4740-codec.h
+++ b/firmware/export/jz4740-codec.h
@@ -24,6 +24,6 @@
 #define VOLUME_MIN -730
 #define VOLUME_MAX  60
 
-void audiohw_set_volume(int v);
+void audiohw_set_master_vol(int vol_l, int vol_r);
 
 #endif /* __JZ4740_CODEC_H_ */