[PATCH] snd-hda-intel: add controls to toggle DC bias on mic ports

[Nickolas Lloyd <ultrageek.lloyd@gmail.com>]

This patch adds a mixer control for the STAC92XX boards to control the
DC bias of mic ports, allowing recording from both powered and
non-powered sources.  It replaces the "Mic Output Switch" with "Mic Jack
Mode" to switch between Mic, Line In, and Line Out.

Signed-off by: Nickolas Lloyd <ultrageek.lloyd@gmail.com>

Note: diffed against alsa-driver-20090513

----
diff -urpN alsa-driver/sound/pci/hda/patch_sigmatel.c
alsa-driver.a/sound/pci/hda/patch_sigmatel.c
--- alsa-driver/sound/pci/hda/patch_sigmatel.c    2009-05-12
22:05:31.000000000 +0000
+++ alsa-driver.a/sound/pci/hda/patch_sigmatel.c    2009-05-13
12:24:17.000000000 +0000
@@ -634,6 +634,96 @@ static int stac92xx_smux_enum_put(struct
     return 0;
 }
 
+static unsigned int stac92xx_vref_set(struct hda_codec *codec,
+                    hda_nid_t nid, unsigned int new_vref)
+{
+    unsigned int error;
+    unsigned int pincfg;
+    pincfg = snd_hda_codec_read(codec, nid, 0,
+                AC_VERB_GET_PIN_WIDGET_CONTROL, 0);
+
+    pincfg &= 0xff;
+    pincfg &= ~(AC_PINCTL_VREFEN | AC_PINCTL_IN_EN | AC_PINCTL_OUT_EN);
+    pincfg |= new_vref;
+
+    if (new_vref == AC_PINCTL_VREF_HIZ)
+        pincfg |= AC_PINCTL_OUT_EN;
+    else
+        pincfg |= AC_PINCTL_IN_EN;
+
+    error = snd_hda_codec_write_cache(codec, nid, 0,
+                    AC_VERB_SET_PIN_WIDGET_CONTROL, pincfg);
+    if (error < 0)
+        return error;
+    else
+        return 1;
+}
+
+static unsigned int stac92xx_vref_get(struct hda_codec *codec,
hda_nid_t nid)
+{
+    unsigned int vref;
+    vref = snd_hda_codec_read(codec, nid, 0,
+                AC_VERB_GET_PIN_WIDGET_CONTROL, 0);
+    vref &= AC_PINCTL_VREFEN;
+    return vref;
+}
+
+static int stac92xx_dc_bias_put(struct snd_kcontrol *kcontrol,
+                struct snd_ctl_elem_value *ucontrol)
+{
+    struct hda_codec *codec = snd_kcontrol_chip(kcontrol);
+    unsigned int new_vref;
+    unsigned int error;
+
+    if (ucontrol->value.enumerated.item[0] == 0)
+        new_vref = AC_PINCTL_VREF_80;
+    else if (ucontrol->value.enumerated.item[0] == 1)
+        new_vref = AC_PINCTL_VREF_GRD;
+    else
+        new_vref = AC_PINCTL_VREF_HIZ;
+
+    if (new_vref != stac92xx_vref_get(codec, kcontrol->private_value)) {
+        error = stac92xx_vref_set(codec,
+                    kcontrol->private_value, new_vref);
+        return error;
+    }
+
+    return 0;
+}
+
+static int stac92xx_dc_bias_get(struct snd_kcontrol *kcontrol,
+                struct snd_ctl_elem_value *ucontrol)
+{
+    struct hda_codec *codec = snd_kcontrol_chip(kcontrol);
+    unsigned int vref = stac92xx_vref_get(codec, kcontrol->private_value);
+    if (vref == AC_PINCTL_VREF_80)
+        ucontrol->value.enumerated.item[0] = 0;
+    else if (vref == AC_PINCTL_VREF_GRD)
+        ucontrol->value.enumerated.item[0] = 1;
+    else if (vref == AC_PINCTL_VREF_HIZ)
+        ucontrol->value.enumerated.item[0] = 2;
+
+    return 0;
+}
+
+static int stac92xx_dc_bias_info(struct snd_kcontrol *kcontrol,
+                struct snd_ctl_elem_info *uinfo)
+{
+    static char *texts[] = {
+        "Mic In", "Line In", "Line Out"
+    };
+
+    uinfo->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
+    uinfo->value.enumerated.items = 3;
+    uinfo->count = 1;
+    if (uinfo->value.enumerated.item >= 3)
+        uinfo->value.enumerated.item = 2;
+    strcpy(uinfo->value.enumerated.name,
+        texts[uinfo->value.enumerated.item]);
+
+    return 0;
+}
+
 static int stac92xx_mux_enum_info(struct snd_kcontrol *kcontrol, struct
snd_ctl_elem_info *uinfo)
 {
     struct hda_codec *codec = snd_kcontrol_chip(kcontrol);
@@ -995,6 +1085,17 @@ static struct hda_verb stac9205_core_ini
         .private_value = verb_read | (verb_write << 16), \
     }
 
+#define DC_BIAS(xname, idx, nid) \
+    { \
+        .iface = SNDRV_CTL_ELEM_IFACE_MIXER, \
+        .name = xname, \
+        .index = idx, \
+        .info = stac92xx_dc_bias_info, \
+        .get = stac92xx_dc_bias_get, \
+        .put = stac92xx_dc_bias_put, \
+        .private_value = nid, \
+    }
+
 static struct snd_kcontrol_new stac9200_mixer[] = {
     HDA_CODEC_VOLUME("Master Playback Volume", 0xb, 0, HDA_OUTPUT),
     HDA_CODEC_MUTE("Master Playback Switch", 0xb, 0, HDA_OUTPUT),
@@ -2702,7 +2803,8 @@ enum {
     STAC_CTL_WIDGET_AMP_VOL,
     STAC_CTL_WIDGET_HP_SWITCH,
     STAC_CTL_WIDGET_IO_SWITCH,
-    STAC_CTL_WIDGET_CLFE_SWITCH
+    STAC_CTL_WIDGET_CLFE_SWITCH,
+    STAC_CTL_WIDGET_DC_BIAS
 };
 
 static struct snd_kcontrol_new stac92xx_control_templates[] = {
@@ -2714,6 +2816,7 @@ static struct snd_kcontrol_new stac92xx_
     STAC_CODEC_HP_SWITCH(NULL),
     STAC_CODEC_IO_SWITCH(NULL, 0),
     STAC_CODEC_CLFE_SWITCH(NULL, 0),
+    DC_BIAS(NULL, 0, 0),
 };
 
 /* add dynamic controls */
@@ -3165,9 +3268,9 @@ static int stac92xx_auto_create_multi_ou
     }
 
     if (spec->mic_switch) {
-        err = stac92xx_add_control(spec, STAC_CTL_WIDGET_IO_SWITCH,
-                       "Mic as Output Switch",
-                       (spec->mic_switch << 8) | 1);
+        err = stac92xx_add_control(spec, STAC_CTL_WIDGET_DC_BIAS,
+                       "Mic Jack Mode",
+                       spec->mic_switch);
         if (err < 0)
             return err;
     }