+ /* The source from any output plugs is for one purpose only. */
+ if (input[0] == AVC_BRIDGECO_PLUG_DIR_OUT) {
+ /*
+ * In BeBoB architecture, the source from music subunit may
+ * bypass from oPCR[0]. This means that this source gives
+ * synchronization to IEEE 1394 cycle start packet.
+ */
+ if (input[1] == AVC_BRIDGECO_PLUG_MODE_SUBUNIT &&
+ input[2] == 0x0c) {
+ *src = SND_BEBOB_CLOCK_TYPE_INTERNAL;
+ goto end;
+ }
+ /* The source from any input units is for several purposes. */
+ } else if (input[1] == AVC_BRIDGECO_PLUG_MODE_UNIT) {
+ if (input[2] == AVC_BRIDGECO_PLUG_UNIT_ISOC) {
+ if (input[3] == 0x00) {
+ /*
+ * This source comes from iPCR[0]. This means
+ * that presentation timestamp calculated by
+ * SYT series of the received packets. In
+ * short, this driver is the master of
+ * synchronization.
+ */
+ *src = SND_BEBOB_CLOCK_TYPE_SYT;
+ goto end;
+ } else {
+ /*
+ * This source comes from iPCR[1-29]. This
+ * means that the synchronization stream is not
+ * the Audio/MIDI compound stream.
+ */
+ *src = SND_BEBOB_CLOCK_TYPE_EXTERNAL;
+ goto end;
+ }
+ } else if (input[2] == AVC_BRIDGECO_PLUG_UNIT_EXT) {
+ /* Check type of this plug. */
+ avc_bridgeco_fill_unit_addr(addr,
+ AVC_BRIDGECO_PLUG_DIR_IN,
+ AVC_BRIDGECO_PLUG_UNIT_EXT,
+ input[3]);
+ err = avc_bridgeco_get_plug_type(bebob->unit, addr,
+ &type);
+ if (err < 0)
+ goto end;
+
+ if (type == AVC_BRIDGECO_PLUG_TYPE_DIG) {
+ /*
+ * SPDIF/ADAT or sometimes (not always) word
+ * clock.
+ */
+ *src = SND_BEBOB_CLOCK_TYPE_EXTERNAL;
+ goto end;
+ } else if (type == AVC_BRIDGECO_PLUG_TYPE_SYNC) {
+ /* Often word clock. */
+ *src = SND_BEBOB_CLOCK_TYPE_EXTERNAL;
+ goto end;
+ } else if (type == AVC_BRIDGECO_PLUG_TYPE_ADDITION) {
+ /*
+ * Not standard.
+ * Mostly, additional internal clock.
+ */
+ *src = SND_BEBOB_CLOCK_TYPE_INTERNAL;
+ goto end;
+ }
+ }
+ }
+
+ /* Not supported. */
+ err = -EIO;