ALSA: usb-audio - Added functionality for E-mu 0404USB/0202USB/TrackerPre

Added functionality:
1) Extension Units support (all XU settings now available at alsamixer,
   kmix, etc):
- "AnalogueIn soft limiter" switch;
- "Sample rate" selector (values 0,1,2,3,4,5 corresponds to 44.1 48 ...
  192 kHz);
- "DigitalIn CLK source" selector (internal/external) (**);
- "DigitalOut format SPDIF/AC3" switch (**);
(**)E-mu-0404usb only.

2) Automatic device sample rate adjustment depending on substream
   samplerate for both capture and playback substream.

[minor coding-style fixes by tiwai]

Signed-off-by: Sergiy Kovalchuk <cnb_zerg@yahoo.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c
index 31b63ea..286fa14 100644
--- a/sound/usb/usbaudio.c
+++ b/sound/usb/usbaudio.c
@@ -1271,6 +1271,47 @@
 }
 
 /*
+ * For E-Mu 0404USB/0202USB/TrackerPre sample rate should be set for device,
+ * not for interface.
+ */
+static void set_format_emu_quirk(struct snd_usb_substream *subs,
+				 struct audioformat *fmt)
+{
+	unsigned char emu_samplerate_id = 0;
+
+	/* When capture is active
+	 * sample rate shouldn't be changed
+	 * by playback substream
+	 */
+	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
+		if (subs->stream->substream[SNDRV_PCM_STREAM_CAPTURE].interface != -1)
+			return;
+	}
+
+	switch (fmt->rate_min) {
+	case 48000:
+		emu_samplerate_id = EMU_QUIRK_SR_48000HZ;
+		break;
+	case 88200:
+		emu_samplerate_id = EMU_QUIRK_SR_88200HZ;
+		break;
+	case 96000:
+		emu_samplerate_id = EMU_QUIRK_SR_96000HZ;
+		break;
+	case 176400:
+		emu_samplerate_id = EMU_QUIRK_SR_176400HZ;
+		break;
+	case 192000:
+		emu_samplerate_id = EMU_QUIRK_SR_192000HZ;
+		break;
+	default:
+		emu_samplerate_id = EMU_QUIRK_SR_44100HZ;
+		break;
+	}
+	snd_emuusb_set_samplerate(subs->stream->chip, emu_samplerate_id);
+}
+
+/*
  * find a matching format and set up the interface
  */
 static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
@@ -1383,6 +1424,14 @@
 
 	subs->cur_audiofmt = fmt;
 
+	switch (subs->stream->chip->usb_id) {
+	case USB_ID(0x041e, 0x3f02): /* E-Mu 0202 USB */
+	case USB_ID(0x041e, 0x3f04): /* E-Mu 0404 USB */
+	case USB_ID(0x041e, 0x3f0a): /* E-Mu Tracker Pre */
+		set_format_emu_quirk(subs, fmt);
+		break;
+	}
+
 #if 0
 	printk(KERN_DEBUG
 	       "setting done: format = %d, rate = %d..%d, channels = %d\n",