[PATCH 2/5] ASoC: Add codec_ch_mask to snd_soc_dai_link_ch_map

[Richard Fitzgerald]

Add a codec_ch_mask member to snd_soc_dai_link_ch_map.

The CPU and codec channel masks are not necessarily the same, and are
quite likely different. SoundWire and I2S/TDM both support assigning
different sample slots to each codec, so for example channel 0 on each
codec could map to different channels at the CPU.

It is also possible for one TX channel to map to multiple RX channels.
So it isn't _always_ safe to assume that the total number of set bits
in the CPU ch_mask is the same as the total number of enabled channels
on the codec.

For example consider this mapping on a capture stream:

CPU0 CODEC0 cpu_ch_mask = 0x03
CPU1 CODEC0 cpu_ch_mask = 0x03

This could be either four TX channels on the codec split across two
receiving CPUs, or two TX channels on the codec duplicated to two CPUs.

Signed-off-by: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
---
 include/sound/soc.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/sound/soc.h b/include/sound/soc.h
index 94c9b75e27e3..5afc34b147b5 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -700,6 +700,7 @@ struct snd_soc_dai_link_ch_map {
 	unsigned int cpu;
 	unsigned int codec;
 	unsigned int cpu_ch_mask;
+	unsigned int codec_ch_mask;
 };
 
 struct snd_soc_dai_link {
-- 
2.47.3