From: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
Renesas Sound device *Hardware* L/R and Linux *Software* L/R are
inverted. Because of this background, it needs to convert L/R.
Then, DVC needs *Hardware* L/R, and Linux needs *Software* L/R.
Because Playback/Capture needs different timing, and there is no
explanation about it on source code / git log, this patch adds it.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
---
sound/soc/sh/rcar/core.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/sound/soc/sh/rcar/core.c b/sound/soc/sh/rcar/core.c
index 7c68f9d..1bf261d 100644
--- a/sound/soc/sh/rcar/core.c
+++ b/sound/soc/sh/rcar/core.c
@@ -310,6 +310,24 @@ u32 rsnd_get_dalign(struct rsnd_mod *mod, struct rsnd_dai_stream *io)
u32 val = 0x76543210;
u32 mask = ~0;
+ /*
+ * *Hardware* L/R and *Software* L/R are inverted.
+ * We need to care about inversion timing to control
+ * Playback/Capture correctly.
+ * The point is [DVC] needs *Hardware* L/R, [MEM] needs *Software* L/R
+ *
+ * sL/R : software L/R
+ * hL/R : hardware L/R
+ * (*) : conversion timing
+ *
+ * Playback
+ * sL/R (*) hL/R hL/R hL/R hL/R hL/R
+ * [MEM] -> [SRC] -> [DVC] -> [CMD] -> [SSIU] -> [SSI] -> codec
+ *
+ * Capture
+ * hL/R hL/R hL/R hL/R hL/R (*) sL/R
+ * codec -> [SSI] -> [SSIU] -> [SRC] -> [DVC] -> [CMD] -> [MEM]
+ */
if (rsnd_io_is_play(io)) {
struct rsnd_mod *src = rsnd_io_to_mod_src(io);
--
1.9.1
