ALSA: cs5535audio: invert EAPD for OLPC (newer than B3)

Fix an audible pop described in <http://dev.laptop.org/ticket/977>.  Originally
based upon fixes by Mitch Bradley and Chris Ball.
Signed-off-by: Andres Salomon <dilinger@debian.org>

sound/pci/cs5535audio/cs5535audio.c

@@ -164,6 +164,9 @@ static int __devinit snd_cs5535audio_mixer(struct cs5535audio *cs5535au)
 	ac97.private_data = cs5535au;
 	ac97.pci = cs5535au->pci;
 
+	/* set any OLPC-specific scaps */
+	olpc_prequirks(card, &ac97);
+
 	if ((err = snd_ac97_mixer(pbus, &ac97, &cs5535au->ac97)) < 0) {
 		snd_printk(KERN_ERR "mixer failed\n");
 		return err;

sound/pci/cs5535audio/cs5535audio.h

@@ -103,9 +103,16 @@ int snd_cs5535audio_resume(struct pci_dev *pci);
 #endif
 
 #ifdef CONFIG_OLPC
-int olpc_quirks(struct snd_card *card, struct snd_ac97 *ac97);
+void __devinit olpc_prequirks(struct snd_card *card,
+		struct snd_ac97_template *ac97);
+int __devinit olpc_quirks(struct snd_card *card, struct snd_ac97 *ac97);
 #else
-#define olpc_quirks(arg, arg2) (0)
+static inline void olpc_prequirks(struct snd_card *card,
+		struct snd_ac97_template *ac97) { }
+static inline int olpc_quirks(struct snd_card *card, struct snd_ac97 *ac97)
+{
+	return 0;
+}
 #endif
 
 int __devinit snd_cs5535audio_pcm(struct cs5535audio *cs5535audio);

sound/pci/cs5535audio/cs5535audio_olpc.c

@@ -103,6 +103,17 @@ static struct snd_kcontrol_new snd_cs5535audio_controls __devinitdata =
 	.private_value = 0
 };
 
+void __devinit olpc_prequirks(struct snd_card *card,
+		struct snd_ac97_template *ac97)
+{
+	if (!machine_is_olpc())
+		return;
+
+	/* invert EAPD if on an OLPC B3 or higher */
+	if (olpc_board_at_least(olpc_board_pre(0xb3)))
+		ac97->scaps |= AC97_SCAP_INV_EAPD;
+}
+
 int __devinit olpc_quirks(struct snd_card *card, struct snd_ac97 *ac97)
 {
 	if (!machine_is_olpc())