ALSA: firewire-motu: refactoring protocol v3 for clock source getter

This commit splits the method to get clock source for protocol
version 3 so that model-dependent operations are explicitly defined.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20200519111641.123211-14-o-takashi@sakamocchi.jpSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/motu/motu-protocol-v3.c

@@ -87,54 +87,100 @@ int snd_motu_protocol_v3_set_clock_rate(struct snd_motu *motu,
 	return 0;
 }
 
-int snd_motu_protocol_v3_get_clock_source(struct snd_motu *motu,
-					  enum snd_motu_clock_source *src)
+static int detect_clock_source_828mk3(struct snd_motu *motu, u32 data,
+				      enum snd_motu_clock_source *src)
 {
-	__be32 reg;
-	u32 data;
-	unsigned int val;
-	int err;
-
-	err = snd_motu_transaction_read(motu, V3_CLOCK_STATUS_OFFSET, &reg,
-					sizeof(reg));
-	if (err < 0)
-		return err;
-	data = be32_to_cpu(reg);
-
-	val = data & V3_CLOCK_SOURCE_MASK;
-	if (val == 0x00) {
+	switch (data) {
+	case 0x00:
 		*src = SND_MOTU_CLOCK_SOURCE_INTERNAL;
-	} else if (val == 0x01) {
+		break;
+	case 0x01:
 		*src = SND_MOTU_CLOCK_SOURCE_WORD_ON_BNC;
-	} else if (val == 0x02) {
+		break;
+	case 0x02:
 		*src = SND_MOTU_CLOCK_SOURCE_SPH;
-	} else if (val == 0x10) {
+		break;
+	case 0x10:
 		*src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_COAX;
-	} else if (val == 0x18 || val == 0x19) {
-		err = snd_motu_transaction_read(motu, V3_OPT_IFACE_MODE_OFFSET,
-						&reg, sizeof(reg));
+		break;
+	case 0x18:
+	case 0x19:
+	{
+		__be32 reg;
+		u32 options;
+		int err;
+
+		err = snd_motu_transaction_read(motu,
+				V3_OPT_IFACE_MODE_OFFSET, &reg, sizeof(reg));
 		if (err < 0)
 			return err;
-		data = be32_to_cpu(reg);
+		options = be32_to_cpu(reg);
 
-		if (val == 0x18) {
-			if (data & V3_NO_ADAT_OPT_IN_IFACE_A)
+		if (data == 0x18) {
+			if (options & V3_NO_ADAT_OPT_IN_IFACE_A)
 				*src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_OPT_A;
 			else
 				*src = SND_MOTU_CLOCK_SOURCE_ADAT_ON_OPT_A;
 		} else {
-			if (data & V3_NO_ADAT_OPT_IN_IFACE_B)
+			if (options & V3_NO_ADAT_OPT_IN_IFACE_B)
 				*src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_OPT_B;
 			else
 				*src = SND_MOTU_CLOCK_SOURCE_ADAT_ON_OPT_B;
 		}
-	} else {
+
+		break;
+	}
+	default:
 		*src = SND_MOTU_CLOCK_SOURCE_UNKNOWN;
+		break;
 	}
 
 	return 0;
 }
 
+static int v3_detect_clock_source(struct snd_motu *motu, u32 data,
+				  enum snd_motu_clock_source *src)
+{
+	switch (data) {
+	case 0x00:
+		*src = SND_MOTU_CLOCK_SOURCE_INTERNAL;
+		break;
+	case 0x01:
+		*src = SND_MOTU_CLOCK_SOURCE_WORD_ON_BNC;
+		break;
+	case 0x02:
+		*src = SND_MOTU_CLOCK_SOURCE_SPH;
+		break;
+	case 0x10:
+		*src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_COAX;
+		break;
+	default:
+		*src = SND_MOTU_CLOCK_SOURCE_UNKNOWN;
+		break;
+	}
+
+	return 0;
+}
+
+int snd_motu_protocol_v3_get_clock_source(struct snd_motu *motu,
+					  enum snd_motu_clock_source *src)
+{
+	__be32 reg;
+	u32 data;
+	int err;
+
+	err = snd_motu_transaction_read(motu, V3_CLOCK_STATUS_OFFSET, &reg,
+					sizeof(reg));
+	if (err < 0)
+		return err;
+	data = be32_to_cpu(reg) & V3_CLOCK_SOURCE_MASK;
+
+	if (motu->spec == &snd_motu_spec_828mk3)
+		return detect_clock_source_828mk3(motu, data, src);
+	else
+		return v3_detect_clock_source(motu, data, src);
+}
+
 int snd_motu_protocol_v3_switch_fetching_mode(struct snd_motu *motu,
 					      bool enable)
 {