ALSA: usb-audio: export snd_usb_feature_unit_ctl

In order to allow quirks functions to hook up to the standard feature
unit op tables, this patch exports a pointer to the struct that is used
internally.

That way, all the code handling the control can be kept private, and
external code can reference the symbol to re-use it.
Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/card.c

@@ -48,6 +48,7 @@
 #include <linux/usb/audio.h>
 #include <linux/usb/audio-v2.h>
 
+#include <sound/control.h>
 #include <sound/core.h>
 #include <sound/info.h>
 #include <sound/pcm.h>

sound/usb/mixer.c

@@ -86,16 +86,6 @@ struct mixer_build {
 	const struct usbmix_selector_map *selector_map;
 };
 
-enum {
-	USB_MIXER_BOOLEAN,
-	USB_MIXER_INV_BOOLEAN,
-	USB_MIXER_S8,
-	USB_MIXER_U8,
-	USB_MIXER_S16,
-	USB_MIXER_U16,
-};
-
-
 /*E-mu 0202/0404/0204 eXtension Unit(XU) control*/
 enum {
 	USB_XU_CLOCK_RATE 		= 0xe301,
@@ -985,6 +975,9 @@ static struct snd_kcontrol_new usb_feature_unit_ctl_ro = {
 	.put = NULL,
 };
 
+/* This symbol is exported in order to allow the mixer quirks to
+ * hook up to the standard feature unit control mechanism */
+struct snd_kcontrol_new *snd_usb_feature_unit_ctl = &usb_feature_unit_ctl;
 
 /*
  * build a feature control

sound/usb/mixer.h

@@ -24,7 +24,16 @@ struct usb_mixer_interface {
 	u8 xonar_u1_status;
 };
 
-#define MAX_CHANNELS	10	/* max logical channels */
+#define MAX_CHANNELS	16	/* max logical channels */
+
+enum {
+	USB_MIXER_BOOLEAN,
+	USB_MIXER_INV_BOOLEAN,
+	USB_MIXER_S8,
+	USB_MIXER_U8,
+	USB_MIXER_S16,
+	USB_MIXER_U16,
+};
 
 struct usb_mixer_elem_info {
 	struct usb_mixer_interface *mixer;

sound/usb/quirks.c

@@ -19,6 +19,7 @@
 #include <linux/usb.h>
 #include <linux/usb/audio.h>
 
+#include <sound/control.h>
 #include <sound/core.h>
 #include <sound/info.h>
 #include <sound/pcm.h>