Commit 3f58f004 authored by Takashi Sakamoto's avatar Takashi Sakamoto Committed by Takashi Iwai
Browse files

ALSA: firewire-motu: detect SPH source of sampling clock 



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: default avatarTakashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20191030080644.1704-4-o-takashi@sakamocchi.jp


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 1ef2ff94

sound/firewire/motu/motu-pcm.c

+2 −1
Original line number Diff line number Diff line
@@ -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;

sound/firewire/motu/motu-proc.c

+1 −0
Original line number Diff line number Diff line
@@ -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",

};

sound/firewire/motu/motu-protocol-v2.c

+3 −0
Original line number Diff line number Diff line
@@ -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;

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

+2 −0
Original line number Diff line number Diff line
@@ -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) {

sound/firewire/motu/motu.h

+1 −0
Original line number Diff line number Diff line
@@ -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,

};

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