ALSA: usb-audio: scarlett2: Improve driver startup messages

Add separate init function to call the existing controls_create
function so a custom error can be displayed if initialisation fails.

Use info level instead of error for notifications.

Display the VID/PID so device_setup is targeted to the right device.

Display "enabled" message to easily confirm that the driver is loaded.
Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/b5d140c65f640faf2427e085fbbc0297b32e5fce.1621584566.git.g@b4.vuSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/mixer_quirks.c

@@ -3060,7 +3060,7 @@ int snd_usb_mixer_apply_create_quirk(struct usb_mixer_interface *mixer)
 	case USB_ID(0x1235, 0x8203): /* Focusrite Scarlett 6i6 2nd Gen */
 	case USB_ID(0x1235, 0x8204): /* Focusrite Scarlett 18i8 2nd Gen */
 	case USB_ID(0x1235, 0x8201): /* Focusrite Scarlett 18i20 2nd Gen */
-		err = snd_scarlett_gen2_controls_create(mixer);
+		err = snd_scarlett_gen2_init(mixer);
 		break;
 
 	case USB_ID(0x041e, 0x323b): /* Creative Sound Blaster E1 */

sound/usb/mixer_scarlett_gen2.c

@@ -1997,38 +1997,11 @@ static int scarlett2_mixer_status_create(struct usb_mixer_interface *mixer)
 	return usb_submit_urb(mixer->urb, GFP_KERNEL);
 }
 
-/* Entry point */
-int snd_scarlett_gen2_controls_create(struct usb_mixer_interface *mixer)
+int snd_scarlett_gen2_controls_create(struct usb_mixer_interface *mixer,
+				      const struct scarlett2_device_info *info)
 {
-	const struct scarlett2_device_info *info;
 	int err;
 
-	/* only use UAC_VERSION_2 */
-	if (!mixer->protocol)
-		return 0;
-
-	switch (mixer->chip->usb_id) {
-	case USB_ID(0x1235, 0x8203):
-		info = &s6i6_gen2_info;
-		break;
-	case USB_ID(0x1235, 0x8204):
-		info = &s18i8_gen2_info;
-		break;
-	case USB_ID(0x1235, 0x8201):
-		info = &s18i20_gen2_info;
-		break;
-	default: /* device not (yet) supported */
-		return -EINVAL;
-	}
-
-	if (!(mixer->chip->setup & SCARLETT2_ENABLE)) {
-		usb_audio_err(mixer->chip,
-			"Focusrite Scarlett Gen 2 Mixer Driver disabled; "
-			"use options snd_usb_audio device_setup=1 "
-			"to enable and report any issues to g@b4.vu");
-		return 0;
-	}
-
 	/* Initialise private data, routing, sequence number */
 	err = scarlett2_init_private(mixer, info);
 	if (err < 0)
@@ -2073,3 +2046,51 @@ int snd_scarlett_gen2_controls_create(struct usb_mixer_interface *mixer)
 
 	return 0;
 }
+
+int snd_scarlett_gen2_init(struct usb_mixer_interface *mixer)
+{
+	struct snd_usb_audio *chip = mixer->chip;
+	const struct scarlett2_device_info *info;
+	int err;
+
+	/* only use UAC_VERSION_2 */
+	if (!mixer->protocol)
+		return 0;
+
+	switch (chip->usb_id) {
+	case USB_ID(0x1235, 0x8203):
+		info = &s6i6_gen2_info;
+		break;
+	case USB_ID(0x1235, 0x8204):
+		info = &s18i8_gen2_info;
+		break;
+	case USB_ID(0x1235, 0x8201):
+		info = &s18i20_gen2_info;
+		break;
+	default: /* device not (yet) supported */
+		return -EINVAL;
+	}
+
+	if (!(chip->setup & SCARLETT2_ENABLE)) {
+		usb_audio_info(chip,
+			"Focusrite Scarlett Gen 2 Mixer Driver disabled; "
+			"use options snd_usb_audio vid=0x%04x pid=0x%04x "
+			"device_setup=1 to enable and report any issues "
+			"to g@b4.vu",
+			USB_ID_VENDOR(chip->usb_id),
+			USB_ID_PRODUCT(chip->usb_id));
+		return 0;
+	}
+
+	usb_audio_info(chip,
+		"Focusrite Scarlett Gen 2 Mixer Driver enabled pid=0x%04x",
+		USB_ID_PRODUCT(chip->usb_id));
+
+	err = snd_scarlett_gen2_controls_create(mixer, info);
+	if (err < 0)
+		usb_audio_err(mixer->chip,
+			      "Error initialising Scarlett Mixer Driver: %d",
+			      err);
+
+	return err;
+}

sound/usb/mixer_scarlett_gen2.h

@@ -2,6 +2,6 @@
 #ifndef __USB_MIXER_SCARLETT_GEN2_H
 #define __USB_MIXER_SCARLETT_GEN2_H
 
-int snd_scarlett_gen2_controls_create(struct usb_mixer_interface *mixer);
+int snd_scarlett_gen2_init(struct usb_mixer_interface *mixer);
 
 #endif /* __USB_MIXER_SCARLETT_GEN2_H */