From fa4db23233eb912234bdfb0b26a38be079c6b5ea Mon Sep 17 00:00:00 2001
From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Date: Wed, 23 Jun 2021 16:59:33 +0900
Subject: [PATCH] ALSA: firewire-motu: fix detection for S/PDIF source on optical interface in v2 protocol
Git-commit: fa4db23233eb912234bdfb0b26a38be079c6b5ea
Patch-mainline: v5.14-rc1
References: git-fixes

The devices in protocol version 2 has a register with flag for IEC 60958
signal detection as source of sampling clock without discrimination
between coaxial and optical interfaces. On the other hand, current
implementation of driver manage to interpret type of signal on optical
interface instead.

This commit fixes the detection of optical/coaxial interface for S/PDIF
signal.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210623075941.72562-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

---
 sound/firewire/motu/motu-protocol-v2.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/sound/firewire/motu/motu-protocol-v2.c b/sound/firewire/motu/motu-protocol-v2.c
index 784073aa1026..f0a0ecad4d74 100644
--- a/sound/firewire/motu/motu-protocol-v2.c
+++ b/sound/firewire/motu/motu-protocol-v2.c
@@ -86,24 +86,23 @@ static int detect_clock_source_optical_model(struct snd_motu *motu, u32 data,
 		*src = SND_MOTU_CLOCK_SOURCE_INTERNAL;
 		break;
 	case 1:
+		*src = SND_MOTU_CLOCK_SOURCE_ADAT_ON_OPT;
+		break;
+	case 2:
 	{
 		__be32 reg;
 
 		// To check the configuration of optical interface.
-		int err = snd_motu_transaction_read(motu, V2_IN_OUT_CONF_OFFSET,
-						    &reg, sizeof(reg));
+		int err = snd_motu_transaction_read(motu, V2_IN_OUT_CONF_OFFSET, &reg, sizeof(reg));
 		if (err < 0)
 			return err;
 
-		if (be32_to_cpu(reg) & 0x00000200)
+		if (((data & V2_OPT_IN_IFACE_MASK) >> V2_OPT_IN_IFACE_SHIFT) == V2_OPT_IFACE_MODE_SPDIF)
 			*src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_OPT;
 		else
-			*src = SND_MOTU_CLOCK_SOURCE_ADAT_ON_OPT;
+			*src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_COAX;
 		break;
 	}
-	case 2:
-		*src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_COAX;
-		break;
 	case 3:
 		*src = SND_MOTU_CLOCK_SOURCE_SPH;
 		break;
-- 
2.26.2