[ALSA] add support for SB Live! 24-Bit External remote control

This patch rewrites the remote control code to use a table for
the peculiarities of the various SB models, and adds support
for a third model.
Signed-off-by: Raimonds Cicans <ray@vardes.lv>
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

sound/usb/usbmixer.c

@@ -46,6 +46,27 @@
 /* ignore error from controls - for debugging */
 /* #define IGNORE_CTL_ERROR */
 
+/*
+ * Sound Blaster remote control configuration
+ *
+ * format of remote control data:
+ * Extigy:       xx 00
+ * Audigy 2 NX:  06 80 xx 00 00 00
+ * Live! 24-bit: 06 80 xx yy 22 83
+ */
+static const struct rc_config {
+	u32 usb_id;
+	u8  offset;
+	u8  length;
+	u8  packet_length;
+	u8  mute_mixer_id;
+	u32 mute_code;
+} rc_configs[] = {
+	{ USB_ID(0x041e, 0x3000), 0, 1, 2,  18, 0x0013 }, /* Extigy       */
+	{ USB_ID(0x041e, 0x3020), 2, 1, 6,  18, 0x0013 }, /* Audigy 2 NX  */
+	{ USB_ID(0x041e, 0x3040), 2, 2, 6,  2,  0x6e91 }, /* Live! 24-bit */
+};
+
 struct usb_mixer_interface {
 	struct snd_usb_audio *chip;
 	unsigned int ctrlif;
@@ -55,11 +76,7 @@ struct usb_mixer_interface {
 	struct usb_mixer_elem_info **id_elems; /* array[256], indexed by unit id */
 
 	/* Sound Blaster remote control stuff */
-	enum {
-		RC_NONE,
-		RC_EXTIGY,
-		RC_AUDIGY2NX,
-	} rc_type;
+	const struct rc_config *rc_cfg;
 	unsigned long rc_hwdep_open;
 	u32 rc_code;
 	wait_queue_head_t rc_waitq;
@@ -1647,7 +1664,7 @@ static void snd_usb_mixer_notify_id(struct usb_mixer_interface *mixer,
 static void snd_usb_mixer_memory_change(struct usb_mixer_interface *mixer,
 					int unitid)
 {
-	if (mixer->rc_type == RC_NONE)
+	if (!mixer->rc_cfg)
 		return;
 	/* unit ids specific to Extigy/Audigy 2 NX: */
 	switch (unitid) {
@@ -1732,20 +1749,19 @@ static void snd_usb_soundblaster_remote_complete(struct urb *urb,
 						 struct pt_regs *regs)
 {
 	struct usb_mixer_interface *mixer = urb->context;
-	/*
-	 * format of remote control data:
-	 * Extigy:	xx 00
-	 * Audigy 2 NX:	06 80 xx 00 00 00
-	 */
-	int offset = mixer->rc_type == RC_EXTIGY ? 0 : 2;
+	const struct rc_config *rc = mixer->rc_cfg;
 	u32 code;
 
-	if (urb->status < 0 || urb->actual_length <= offset)
+	if (urb->status < 0 || urb->actual_length < rc->packet_length)
 		return;
-	code = mixer->rc_buffer[offset];
+
+	code = mixer->rc_buffer[rc->offset];
+	if (rc->length == 2)
+		code |= mixer->rc_buffer[rc->offset + 1] << 8;
+
 	/* the Mute button actually changes the mixer control */
-	if (code == 13)
-		snd_usb_mixer_notify_id(mixer, 18);
+	if (code == rc->mute_code)
+		snd_usb_mixer_notify_id(mixer, rc->mute_mixer_id);
 	mixer->rc_code = code;
 	wmb();
 	wake_up(&mixer->rc_waitq);
@@ -1801,21 +1817,17 @@ static unsigned int snd_usb_sbrc_hwdep_poll(struct snd_hwdep *hw, struct file *f
 static int snd_usb_soundblaster_remote_init(struct usb_mixer_interface *mixer)
 {
 	struct snd_hwdep *hwdep;
-	int err, len;
+	int err, len, i;
 
-	switch (mixer->chip->usb_id) {
-	case USB_ID(0x041e, 0x3000):
-		mixer->rc_type = RC_EXTIGY;
-		len = 2;
-		break;
-	case USB_ID(0x041e, 0x3020):
-		mixer->rc_type = RC_AUDIGY2NX;
-		len = 6;
-		break;
-	default:
+	for (i = 0; i < ARRAY_SIZE(rc_configs); ++i)
+		if (rc_configs[i].usb_id == mixer->chip->usb_id)
+			break;
+	if (i >= ARRAY_SIZE(rc_configs))
 		return 0;
-	}
+	mixer->rc_cfg = &rc_configs[i];
 
+	len = mixer->rc_cfg->packet_length;
+	
 	init_waitqueue_head(&mixer->rc_waitq);
 	err = snd_hwdep_new(mixer->chip->card, "SB remote control", 0, &hwdep);
 	if (err < 0)