diff options
| -rw-r--r-- | sound/soc/renesas/rcar/msiof.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/sound/soc/renesas/rcar/msiof.c b/sound/soc/renesas/rcar/msiof.c index df664800bf60..330b65b29597 100644 --- a/sound/soc/renesas/rcar/msiof.c +++ b/sound/soc/renesas/rcar/msiof.c @@ -46,6 +46,25 @@ * Setup both direction (Playback/Capture) in the same time. */ +/* + * [NOTE-R/L] + * + * The data of Captured might be R/L opposite. + * + * This driver is assuming MSIOF is used as Clock/Frame Consumer Mode, and there is a case that some + * Codec (= Clock/Frame Provider) might output Clock/Frame before setup MSIOF. It depends on Codec + * driver implementation. + * + * MSIOF will capture data without checking SYNC signal Hi/Low (= R/L). + * + * This means, if MSIOF RXE bit was set as 1 in case of SYNC signal was Hi (= R) timing, it will + * start capture data since next SYNC low singla (= L). Because Linux assumes sound data is lined + * up as R->L->R->L->..., the data R/L will be opposite. + * + * The only solution in this case is start CLK/SYNC *after* MSIOF settings, but it depends when and + * how Codec driver start it. + */ + #include <linux/module.h> #include <linux/of.h> #include <linux/of_dma.h> |