ALSA: snd-usb-caiaq: Restore 'Control vinyl' input mode on A4DJ

This feature was undocumented on early A4DJ units. It is indicated
by lighting both the 'line' and 'phono' lamps at the same time.
Newer units document this and the newer Windows drivers enable this
for all units, so restore the functionality.

This patch simplifies the code and changes the mode mapping to match
the A8DJ, favouring simpler code and consistency over keeping the
existing mapping.

Both 'Control vinyl' and 'Phono' input modes enable the hardware
preamp. The difference is the input impedance.

This reverts commit 9a9527e.

Acked-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Mark Hills <mark@pogo.org.uk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/caiaq/control.c b/sound/usb/caiaq/control.c
index 36ed703..70c3866 100644
--- a/sound/usb/caiaq/control.c
+++ b/sound/usb/caiaq/control.c
@@ -42,8 +42,9 @@
 
 	switch (dev->chip.usb_id) {
 	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO8DJ):
+	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO4DJ):
 		if (pos == 0) {
-			/* current input mode of A8DJ */
+			/* current input mode of A8DJ and A4DJ */
 			uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
 			uinfo->value.integer.min = 0;
 			uinfo->value.integer.max = 2;
@@ -51,16 +52,6 @@
 		}
 		break;
 
-	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO4DJ):
-		if (pos == 0) {
-			/* current input mode of A4DJ */
-			uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
-			uinfo->value.integer.min = 0;
-			uinfo->value.integer.max = 1;
-			return 0;
-		}
-		break;
-
 	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLX1):
 		maxval = 127;
 		break;
@@ -86,14 +77,6 @@
 	struct snd_usb_caiaqdev *dev = caiaqdev(chip->card);
 	int pos = kcontrol->private_value;
 
-	if (dev->chip.usb_id ==
-		USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO4DJ)) {
-		/* A4DJ has only one control */
-		/* do not expose hardware input mode 0 */
-		ucontrol->value.integer.value[0] = dev->control_state[0] - 1;
-		return 0;
-	}
-
 	if (pos & CNT_INTVAL)
 		ucontrol->value.integer.value[0]
 			= dev->control_state[pos & ~CNT_INTVAL];
@@ -113,15 +96,6 @@
 	unsigned char cmd = EP1_CMD_WRITE_IO;
 
 	switch (dev->chip.usb_id) {
-	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_AUDIO4DJ): {
-		/* A4DJ has only one control */
-		/* do not expose hardware input mode 0 */
-		dev->control_state[0] = ucontrol->value.integer.value[0] + 1;
-		snd_usb_caiaq_send_command(dev, EP1_CMD_WRITE_IO,
-				dev->control_state, sizeof(dev->control_state));
-		return 1;
-	}
-
 	case USB_ID(USB_VID_NATIVEINSTRUMENTS, USB_PID_TRAKTORKONTROLX1):
 		cmd = EP1_CMD_DIMM_LEDS;
 		break;