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-rw-r--r--Documentation/sound/alsa/soc/clocking.txt13
1 files changed, 9 insertions, 4 deletions
diff --git a/Documentation/sound/alsa/soc/clocking.txt b/Documentation/sound/alsa/soc/clocking.txt
index 88a16c9..1f55fd8 100644
--- a/Documentation/sound/alsa/soc/clocking.txt
+++ b/Documentation/sound/alsa/soc/clocking.txt
@@ -26,9 +26,9 @@ between the codec and CPU.
The DAI also has a frame clock to signal the start of each audio frame. This
clock is sometimes referred to as LRC (left right clock) or FRAME. This clock
-runs at exactly the sample rate.
+runs at exactly the sample rate (LRC = Rate).
-Bit Clock is usually always a ratio of MCLK or a multiple of LRC. i.e.
+Bit Clock can be generated as follows:-
BCLK = MCLK / x
@@ -36,9 +36,14 @@ BCLK = MCLK / x
BCLK = LRC * x
+ or
+
+BCLK = LRC * Channels * Word Size
+
This relationship depends on the codec or SoC CPU in particular. ASoC can quite
-easily match a codec that generates BCLK by division (FSBD) with a CPU that
-generates BCLK by multiplication (FSB).
+easily match BCLK generated by division (SND_SOC_DAI_BFS_DIV) with BCLK by
+multiplication (SND_SOC_DAI_BFS_RATE) or BCLK generated by
+Rate * Channels * Word size (RCW or SND_SOC_DAI_BFS_RCW).
ASoC Clocking