[ALSA] ASoC AC97 device reg bugfix

This patch fixes a bug whereby AC97 bus device data was being clobbered
when AC97 codecs using the generic ac97_codec.c driver were being
registered. Codecs that didn't use the generic driver were unaffected
(e.g. WM9712, WM9713).
Changes:-
 o Add new AC97 codec class for custom (or need bus dev registration)
AC97 codecs.
 o Only register/deregister this custom codec device with the AC97 bus.
The generic AC97 driver already does this for generic codec devices.
This may be related to bug #3038 :-
https://bugtrack.alsa-project.org/alsa-bug/view.php?id=3038

Signed-off-by: Liam Girdwood <lg@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 36519ae..92d5d91 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -116,6 +116,7 @@
 static inline const char* get_dai_name(int type)
 {
 	switch(type) {
+	case SND_SOC_DAI_AC97_BUS:
 	case SND_SOC_DAI_AC97:
 		return "AC97";
 	case SND_SOC_DAI_I2S:
@@ -1099,7 +1100,8 @@
 				continue;
 			}
 		}
-		if (socdev->machine->dai_link[i].cpu_dai->type == SND_SOC_DAI_AC97)
+		if (socdev->machine->dai_link[i].codec_dai->type == 
+			SND_SOC_DAI_AC97_BUS)
 			ac97 = 1;
 	}
 	snprintf(codec->card->shortname, sizeof(codec->card->shortname),
@@ -1148,11 +1150,21 @@
 void snd_soc_free_pcms(struct snd_soc_device *socdev)
 {
 	struct snd_soc_codec *codec = socdev->codec;
+#ifdef CONFIG_SND_SOC_AC97_BUS
+	struct snd_soc_codec_dai *codec_dai;
+	int i;
+#endif
 
 	mutex_lock(&codec->mutex);
 #ifdef CONFIG_SND_SOC_AC97_BUS
-	if (codec->ac97)
-		soc_ac97_dev_unregister(codec);
+	for(i = 0; i < codec->num_dai; i++) {
+		codec_dai = &codec->dai[i];
+		if (codec_dai->type == SND_SOC_DAI_AC97_BUS && codec->ac97) {
+			soc_ac97_dev_unregister(codec);
+			goto free_card;
+		}
+	}
+free_card:
 #endif
 
 	if (codec->card)