ALSA: bebob: code refactoring for stream format detection

ALSA bebob driver scans supported formats of packet for each direction
when probing the target device. Some helper functions are used for the
scanning, however its implementation is not necessarily irredundant.

This commit refactors the helper functions to remove redundant codes.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210321032831.340278-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/bebob/bebob_stream.c

@@ -796,42 +796,42 @@ parse_stream_formation(u8 *buf, unsigned int len,
 	return 0;
 }
 
-static int
-fill_stream_formations(struct snd_bebob *bebob, enum avc_bridgeco_plug_dir dir,
-		       unsigned short pid)
+static int fill_stream_formations(struct snd_bebob *bebob, u8 addr[AVC_BRIDGECO_ADDR_BYTES],
+				  enum avc_bridgeco_plug_dir plug_dir, unsigned int plug_id,
+				  struct snd_bebob_stream_formation *formations)
 {
+	enum avc_bridgeco_plug_type plug_type;
 	u8 *buf;
-	struct snd_bebob_stream_formation *formations;
 	unsigned int len, eid;
-	u8 addr[AVC_BRIDGECO_ADDR_BYTES];
 	int err;
 
+	avc_bridgeco_fill_unit_addr(addr, plug_dir, AVC_BRIDGECO_PLUG_UNIT_ISOC, plug_id);
+
+	err = avc_bridgeco_get_plug_type(bebob->unit, addr, &plug_type);
+	if (err < 0) {
+		dev_err(&bebob->unit->device,
+			"Fail to get type for isoc %d plug 0: %d\n", plug_dir, err);
+		return err;
+	} else if (plug_type != AVC_BRIDGECO_PLUG_TYPE_ISOC)
+		return -ENXIO;
+
 	buf = kmalloc(FORMAT_MAXIMUM_LENGTH, GFP_KERNEL);
 	if (buf == NULL)
 		return -ENOMEM;
 
-	if (dir == AVC_BRIDGECO_PLUG_DIR_IN)
-		formations = bebob->rx_stream_formations;
-	else
-		formations = bebob->tx_stream_formations;
+	for (eid = 0; eid < SND_BEBOB_STRM_FMT_ENTRIES; ++eid) {
+		avc_bridgeco_fill_unit_addr(addr, plug_dir, AVC_BRIDGECO_PLUG_UNIT_ISOC, plug_id);
 
-	for (eid = 0; eid < SND_BEBOB_STRM_FMT_ENTRIES; eid++) {
 		len = FORMAT_MAXIMUM_LENGTH;
-		avc_bridgeco_fill_unit_addr(addr, dir,
-					    AVC_BRIDGECO_PLUG_UNIT_ISOC, pid);
-		err = avc_bridgeco_get_plug_strm_fmt(bebob->unit, addr, buf,
-						     &len, eid);
-		/* No entries remained. */
+		err = avc_bridgeco_get_plug_strm_fmt(bebob->unit, addr, buf, &len, eid);
+		// No entries remained.
 		if (err == -EINVAL && eid > 0) {
 			err = 0;
 			break;
 		} else if (err < 0) {
 			dev_err(&bebob->unit->device,
-			"fail to get stream format %d for isoc %s plug %d:%d\n",
-				eid,
-				(dir == AVC_BRIDGECO_PLUG_DIR_IN) ? "in" :
-								    "out",
-				pid, err);
+				"fail to get stream format %d for isoc %d plug %d:%d\n",
+				eid, plug_dir, plug_id, err);
 			break;
 		}
 
@@ -908,33 +908,13 @@ int snd_bebob_stream_discover(struct snd_bebob *bebob)
 		goto end;
 	}
 
-	avc_bridgeco_fill_unit_addr(addr, AVC_BRIDGECO_PLUG_DIR_IN,
-				    AVC_BRIDGECO_PLUG_UNIT_ISOC, 0);
-	err = avc_bridgeco_get_plug_type(bebob->unit, addr, &type);
-	if (err < 0) {
-		dev_err(&bebob->unit->device,
-			"fail to get type for isoc in plug 0: %d\n", err);
-		goto end;
-	} else if (type != AVC_BRIDGECO_PLUG_TYPE_ISOC) {
-		err = -ENOSYS;
-		goto end;
-	}
-	err = fill_stream_formations(bebob, AVC_BRIDGECO_PLUG_DIR_IN, 0);
+	err = fill_stream_formations(bebob, addr, AVC_BRIDGECO_PLUG_DIR_IN, 0,
+				     bebob->rx_stream_formations);
 	if (err < 0)
 		goto end;
 
-	avc_bridgeco_fill_unit_addr(addr, AVC_BRIDGECO_PLUG_DIR_OUT,
-				    AVC_BRIDGECO_PLUG_UNIT_ISOC, 0);
-	err = avc_bridgeco_get_plug_type(bebob->unit, addr, &type);
-	if (err < 0) {
-		dev_err(&bebob->unit->device,
-			"fail to get type for isoc out plug 0: %d\n", err);
-		goto end;
-	} else if (type != AVC_BRIDGECO_PLUG_TYPE_ISOC) {
-		err = -ENOSYS;
-		goto end;
-	}
-	err = fill_stream_formations(bebob, AVC_BRIDGECO_PLUG_DIR_OUT, 0);
+	err = fill_stream_formations(bebob, addr, AVC_BRIDGECO_PLUG_DIR_OUT, 0,
+				     bebob->tx_stream_formations);
 	if (err < 0)
 		goto end;