sound: usb: make the USB MIDI module more independent

Remove the dependecy from the USB MIDI code on the snd_usb_audio
structure.  This allows using the USB MIDI module from another driver
without having to pretend to be the generic USB audio driver.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/usbaudio.c

@@ -2893,7 +2893,9 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif)
 		if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||
 		     altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&
 		    altsd->bInterfaceSubClass == USB_SUBCLASS_MIDI_STREAMING) {
-			if (snd_usb_create_midi_interface(chip, iface, NULL) < 0) {
+			int err = snd_usbmidi_create(chip->card, iface,
+						     &chip->midi_list, NULL);
+			if (err < 0) {
 				snd_printk(KERN_ERR "%d:%u:%d: cannot create sequencer device\n", dev->devnum, ctrlif, j);
 				continue;
 			}
@@ -3038,12 +3040,11 @@ static int create_uaxx_quirk(struct snd_usb_audio *chip,
 			.type = QUIRK_MIDI_FIXED_ENDPOINT,
 			.data = &uaxx_ep
 		};
-		if (chip->usb_id == USB_ID(0x0582, 0x002b))
-			return snd_usb_create_midi_interface(chip, iface,
-							     &ua700_quirk);
-		else
-			return snd_usb_create_midi_interface(chip, iface,
-							     &uaxx_quirk);
+		const struct snd_usb_audio_quirk *quirk =
+			chip->usb_id == USB_ID(0x0582, 0x002b)
+			? &ua700_quirk : &uaxx_quirk;
+		return snd_usbmidi_create(chip->card, iface,
+					  &chip->midi_list, quirk);
 	}
 
 	if (altsd->bNumEndpoints != 1)
@@ -3370,6 +3371,13 @@ static int audiophile_skip_setting_quirk(struct snd_usb_audio *chip,
 	return 0; /* keep this altsetting */
 }
 
+static int create_any_midi_quirk(struct snd_usb_audio *chip,
+				 struct usb_interface *intf,
+				 const struct snd_usb_audio_quirk *quirk)
+{
+	return snd_usbmidi_create(chip->card, intf, &chip->midi_list, quirk);
+}
+
 /*
  * audio-interface quirks
  *
@@ -3387,14 +3395,14 @@ static int snd_usb_create_quirk(struct snd_usb_audio *chip,
 	static const quirk_func_t quirk_funcs[] = {
 		[QUIRK_IGNORE_INTERFACE] = ignore_interface_quirk,
 		[QUIRK_COMPOSITE] = create_composite_quirk,
-		[QUIRK_MIDI_STANDARD_INTERFACE] = snd_usb_create_midi_interface,
-		[QUIRK_MIDI_FIXED_ENDPOINT] = snd_usb_create_midi_interface,
-		[QUIRK_MIDI_YAMAHA] = snd_usb_create_midi_interface,
-		[QUIRK_MIDI_MIDIMAN] = snd_usb_create_midi_interface,
-		[QUIRK_MIDI_NOVATION] = snd_usb_create_midi_interface,
-		[QUIRK_MIDI_FASTLANE] = snd_usb_create_midi_interface,
-		[QUIRK_MIDI_EMAGIC] = snd_usb_create_midi_interface,
-		[QUIRK_MIDI_CME] = snd_usb_create_midi_interface,
+		[QUIRK_MIDI_STANDARD_INTERFACE] = create_any_midi_quirk,
+		[QUIRK_MIDI_FIXED_ENDPOINT] = create_any_midi_quirk,
+		[QUIRK_MIDI_YAMAHA] = create_any_midi_quirk,
+		[QUIRK_MIDI_MIDIMAN] = create_any_midi_quirk,
+		[QUIRK_MIDI_NOVATION] = create_any_midi_quirk,
+		[QUIRK_MIDI_FASTLANE] = create_any_midi_quirk,
+		[QUIRK_MIDI_EMAGIC] = create_any_midi_quirk,
+		[QUIRK_MIDI_CME] = create_any_midi_quirk,
 		[QUIRK_AUDIO_STANDARD_INTERFACE] = create_standard_audio_quirk,
 		[QUIRK_AUDIO_FIXED_ENDPOINT] = create_fixed_stream_quirk,
 		[QUIRK_AUDIO_EDIROL_UA1000] = create_ua1000_quirk,

sound/usb/usbaudio.h

@@ -132,7 +132,6 @@ struct snd_usb_audio {
 	int pcm_devs;
 
 	struct list_head midi_list;	/* list of midi interfaces */
-	int next_midi_device;
 
 	struct list_head mixer_list;	/* list of mixer interfaces */
 };
@@ -227,8 +226,10 @@ int snd_usb_create_mixer(struct snd_usb_audio *chip, int ctrlif,
 			 int ignore_error);
 void snd_usb_mixer_disconnect(struct list_head *p);
 
-int snd_usb_create_midi_interface(struct snd_usb_audio *chip, struct usb_interface *iface,
-				  const struct snd_usb_audio_quirk *quirk);
+int snd_usbmidi_create(struct snd_card *card,
+		       struct usb_interface *iface,
+		       struct list_head *midi_list,
+		       const struct snd_usb_audio_quirk *quirk);
 void snd_usbmidi_input_stop(struct list_head* p);
 void snd_usbmidi_input_start(struct list_head* p);
 void snd_usbmidi_disconnect(struct list_head *p);