[alsa-devel] [PATCH 3/6] ALSA: firewire-motu: detect SPH source of sampling clock

[Takashi Sakamoto]

In MOTU FireWire series, devices have a mode to generate sampling clock
from a sequence of source packet header (SPH) included in each data block
of received packet. This mode is used for several purposes such as mode
for SMPTE time code, sync to the other sound cards and so on.

This commit adds support for the SPH mode.

Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
---
 sound/firewire/motu/motu-pcm.c         | 3 ++-
 sound/firewire/motu/motu-proc.c        | 1 +
 sound/firewire/motu/motu-protocol-v2.c | 3 +++
 sound/firewire/motu/motu-protocol-v3.c | 2 ++
 sound/firewire/motu/motu.h             | 1 +
 5 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/sound/firewire/motu/motu-pcm.c b/sound/firewire/motu/motu-pcm.c
index 55d3d6661731..490408b49157 100644
--- a/sound/firewire/motu/motu-pcm.c
+++ b/sound/firewire/motu/motu-pcm.c
@@ -159,7 +159,8 @@ static int pcm_open(struct snd_pcm_substream *substream)
 	// When source of clock is not internal or any stream is reserved for
 	// transmission of PCM frames, the available sampling rate is limited
 	// at current one.
-	if (src != SND_MOTU_CLOCK_SOURCE_INTERNAL ||
+	if ((src != SND_MOTU_CLOCK_SOURCE_INTERNAL &&
+	     src != SND_MOTU_CLOCK_SOURCE_SPH) ||
 	    (motu->substreams_counter > 0 && d->events_per_period > 0)) {
 		unsigned int frames_per_period = d->events_per_period;
 		unsigned int frames_per_buffer = d->events_per_buffer;
diff --git a/sound/firewire/motu/motu-proc.c b/sound/firewire/motu/motu-proc.c
index 4e5767c0c8d7..b47ba818343f 100644
--- a/sound/firewire/motu/motu-proc.c
+++ b/sound/firewire/motu/motu-proc.c
@@ -19,6 +19,7 @@ static const char *const clock_names[] = {
 	[SND_MOTU_CLOCK_SOURCE_SPDIF_ON_COAX] = "S/PCIF on coaxial interface",
 	[SND_MOTU_CLOCK_SOURCE_AESEBU_ON_XLR] = "AESEBU on XLR interface",
 	[SND_MOTU_CLOCK_SOURCE_WORD_ON_BNC] = "Word clock on BNC interface",
+	[SND_MOTU_CLOCK_SOURCE_SPH] = "Source packet header",
 	[SND_MOTU_CLOCK_SOURCE_UNKNOWN] = "Unknown",
 };
 
diff --git a/sound/firewire/motu/motu-protocol-v2.c b/sound/firewire/motu/motu-protocol-v2.c
index a42f77fc3858..2757e5b42b9b 100644
--- a/sound/firewire/motu/motu-protocol-v2.c
+++ b/sound/firewire/motu/motu-protocol-v2.c
@@ -114,6 +114,9 @@ static int v2_get_clock_source(struct snd_motu *motu,
 	case 2:
 		*src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_COAX;
 		break;
+	case 3:
+		*src = SND_MOTU_CLOCK_SOURCE_SPH;
+		break;
 	case 4:
 		*src = SND_MOTU_CLOCK_SOURCE_WORD_ON_BNC;
 		break;
diff --git a/sound/firewire/motu/motu-protocol-v3.c b/sound/firewire/motu/motu-protocol-v3.c
index ba5794c724be..d1545e2b5caa 100644
--- a/sound/firewire/motu/motu-protocol-v3.c
+++ b/sound/firewire/motu/motu-protocol-v3.c
@@ -104,6 +104,8 @@ static int v3_get_clock_source(struct snd_motu *motu,
 		*src = SND_MOTU_CLOCK_SOURCE_INTERNAL;
 	} else if (val == 0x01) {
 		*src = SND_MOTU_CLOCK_SOURCE_WORD_ON_BNC;
+	} else if (val == 0x02) {
+		*src = SND_MOTU_CLOCK_SOURCE_SPH;
 	} else if (val == 0x10) {
 		*src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_COAX;
 	} else if (val == 0x18 || val == 0x19) {
diff --git a/sound/firewire/motu/motu.h b/sound/firewire/motu/motu.h
index 08e3d568221d..bd782ee4e763 100644
--- a/sound/firewire/motu/motu.h
+++ b/sound/firewire/motu/motu.h
@@ -104,6 +104,7 @@ enum snd_motu_clock_source {
 	SND_MOTU_CLOCK_SOURCE_SPDIF_ON_COAX,
 	SND_MOTU_CLOCK_SOURCE_AESEBU_ON_XLR,
 	SND_MOTU_CLOCK_SOURCE_WORD_ON_BNC,
+	SND_MOTU_CLOCK_SOURCE_SPH,
 	SND_MOTU_CLOCK_SOURCE_UNKNOWN,
 };
 
-- 
2.20.1