[PATCH 2/2] ASoC: amd: acp: document PDM controller topology for ACP7.B/7.F

[Vijendar Mukunda <Vijendar.Mukunda@amd.com>]

Add a block comment above the ASOC_SDW_ACP_DMIC / ASOC_SDW_ACP_DMIC1
quirk bits and annotate each bit with its role.

ASOC_SDW_ACP_DMIC (BIT(5)) is a generic DMIC-enable flag used across
all ACP platforms; on ACP7.B/7.F it additionally identifies the PDM0
controller.  ASOC_SDW_ACP_DMIC1 (BIT(6)) selects the PDM1 controller
and is ACP7.B/7.F-specific. Both ACP7.B/7.F controllers support a
2-channel stereo capture path, and BIOS wires exactly one per platform.

Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@amd.com>
---
 sound/soc/amd/acp/soc_amd_sdw_common.h | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/sound/soc/amd/acp/soc_amd_sdw_common.h b/sound/soc/amd/acp/soc_amd_sdw_common.h
index 07837a2cfa54..21b059b74626 100644
--- a/sound/soc/amd/acp/soc_amd_sdw_common.h
+++ b/sound/soc/amd/acp/soc_amd_sdw_common.h
@@ -28,8 +28,15 @@
 
 #define SOC_JACK_JDSRC(quirk)		((quirk) & GENMASK(3, 0))
 #define ASOC_SDW_FOUR_SPK		BIT(4)
-#define ASOC_SDW_ACP_DMIC		BIT(5)
-#define ASOC_SDW_ACP_DMIC1		BIT(6)	/* select DMIC1 controller for ACP7.B/7.F */
+/*
+ * ASOC_SDW_ACP_DMIC is a generic DMIC-enable flag used across all ACP
+ * platforms. On ACP7.B/7.F it additionally identifies the PDM0 controller;
+ * ASOC_SDW_ACP_DMIC1 selects PDM1 on ACP7.B/7.F instead. Both ACP7.B/7.F
+ * controllers support a 2-channel stereo capture path, and BIOS wires exactly
+ * one per platform.
+ */
+#define ASOC_SDW_ACP_DMIC		BIT(5)	/* enable DMIC; PDM0 on ACP7.B/7.F */
+#define ASOC_SDW_ACP_DMIC1		BIT(6)	/* PDM1 / DMIC1, ACP7.B/7.F only */
 #define ASOC_SDW_CODEC_SPKR		BIT(15)
 
 #define AMD_SDW0	0
-- 
2.53.0