[PATCH 2/3] AVRCP: Add Passthrough signal

[David Stockwell <dstockwell@frequency-one.com>]

Add Passthrough signal, passing key state.

If key is Vendor Unique (0x7E), also pass vendor's company_id and vendor-
unique message as string.

Signed-off-by: David Stockwell <dstockwell@frequency-one.com>
---
 audio/control.c     |   75 
++++++++++++++++++++++++++++++++++++++++++++++++++-
 doc/control-api.txt |   14 +++------
 2 files changed, 79 insertions(+), 10 deletions(-)

diff --git a/audio/control.c b/audio/control.c
index 882c9fb..4e10cac 100644
--- a/audio/control.c
+++ b/audio/control.c
@@ -106,6 +106,8 @@
 #define FORWARD_OP		0x4b
 #define BACKWARD_OP		0x4c
 
+#define VENDOR_UNIQUE_OP	0x7E
+
 /* Company IDs for vendor dependent commands */
 #define IEEEID_BTSIG		0x001958
 
@@ -470,6 +472,15 @@ static sdp_record_t *avrcp_tg_record(void)
 	return record;
 }
 
+/**
+ *	get_company_id:
+ *
+ *	Return three-byte Company_ID from AVRCP message
+ */
+static uint32_t get_company_id(uint8_t *cid) {
+	return *cid << 16 | *(cid + 1) << 8 | *(cid + 2);
+}
+
 static int send_event(int fd, uint16_t type, uint16_t code, int32_t value)
 {
 	struct uinput_event event;
@@ -491,16 +502,77 @@ static void send_key(int fd, uint16_t key, int pressed)
 	send_event(fd, EV_SYN, SYN_REPORT, 0);
 }
 
+/**
+ *	handle_panel_passthrough:
+ *
+ *	Handles AVRCP 1.0+ PASSTHROUGH command, passes the keystroke to uinput.
+ *
+ *	Added a Passthrough signal, with the key state and the optional
+ *	following company_id and vendor-unique message.
+ */
+
 static void handle_panel_passthrough(struct control *control,
 					const unsigned char *operands,
 					int operand_count)
 {
 	const char *status;
 	int pressed, i;
-
+	uint8_t		key_pressed;
+	gboolean	key_status;
+	uint32_t	pass_company_id;
+	gchar		*pass_string;
+	
 	if (operand_count == 0)
 		return;
 
+	/*
+	 * Following creates the Passthrough signal.
+	 * Key_state is zero if key is pressed (AVRCP v13r00 sect 24, p89)
+	 */
+
+	key_pressed = operands[0] & 0x7F;
+	key_status = ((operands[0] & 0x80) == 0);
+
+	DBG("Passthrough Key: %x Pressed: %s", key_pressed,
+						key_status ? "true" : "false");
+	if (key_pressed==VENDOR_UNIQUE_OP) {
+		if (operands[1] > 3) {
+			pass_company_id = get_company_id((uint8_t *) &operands[2]);
+			pass_string = g_strndup((const char *) &operands[5],
+						(gsize) operands[1] - 3);
+			DBG("Passthrough Company_ID: %06X String: %s",
+			    pass_company_id, pass_string);
+		} else if (operands[1] == 3) {
+			pass_company_id = get_company_id((uint8_t *) &operands[2]);
+			pass_string = (gchar *) g_malloc0(1);
+			DBG("Passthrough Company_ID: %06X String: <none>",
+			    pass_company_id);
+		} else {
+			pass_company_id = 0;
+			pass_string = (gchar *) g_malloc0(1);
+			DBG("Passthrough: No Company_ID or String!");
+		};
+	} else {
+		pass_company_id = 0;
+		pass_string = (gchar *) g_malloc0(1);
+	};
+
+	/*
+	 * Generate passthrough signal only if not BTSIG Company_ID.
+	 * For BTSIG, passthrough only for Group Navigation (unimplemented).
+	 */
+
+	if (pass_company_id != IEEEID_BTSIG)
+		g_dbus_emit_signal(control->dev->conn, control->dev->path,
+			   AUDIO_CONTROL_INTERFACE, "Passthrough",
+			   DBUS_TYPE_BYTE, &key_pressed,
+			   DBUS_TYPE_BOOLEAN, &key_status,
+			   DBUS_TYPE_UINT32, &pass_company_id,
+			   DBUS_TYPE_STRING, &pass_string,
+			   DBUS_TYPE_INVALID);
+	
+	g_free(pass_string);
+
 	if (operands[0] & 0x80) {
 		status = "released";
 		pressed = 0;
@@ -2279,6 +2351,7 @@ static GDBusSignalTable control_signals[] = {
 	{ "Connected",			"",	G_DBUS_SIGNAL_FLAG_DEPRECATED},
 	{ "Disconnected",		"",	G_DBUS_SIGNAL_FLAG_DEPRECATED},
 	{ "PropertyChanged",		"sv"	},
+	{ "Passthrough",		"ybus"	},
 	{ NULL, NULL }
 };
 
diff --git a/doc/control-api.txt b/doc/control-api.txt
index a7e5cbb..64ea5d3 100644
--- a/doc/control-api.txt
+++ b/doc/control-api.txt
@@ -55,18 +55,14 @@ Signals		Connected()
 			Sent when the AVRCP connection to the remote device
 			has been disconnected.
 
-		Passthrough(uint8 key, boolean state, int32 company_id,
+		Passthrough(uint8 key, boolean state, uint32 company_id,
 								string op_data)
 
-			Called when Passthrough command is received from
-			connected device.
+			Sent when Passthrough received from CT.
 
-			NOTE: according to the AV/C Subpanel Spec, company_id
-			and op_data are passed ONLY when the key is
-			"Vendor_Unique", or 0x7E.
-
-			When the key is NOT 0x7E, the signal returns
-			company_id=-1, and zero-length op_data.
+			Company_id and op_data returned only when key is 0x7E
+			(OP_VENDOR_UNIQUE).  Otherwise, returns zero for
+			company_id, and zero-length op_data.
 
 		VendorDependentReceived(string op_data)
 
-- 
1.7.3.4