[ALSA] hda-codec - make volume knob, the master volume for sigmatel codecs

VolumeKnob is present on most sigmatel codecs, it allows to decrease
volume of all DACs at once, it is a kind of post-procesing volume.
Note that all output amps of sigmatel only decrease volume, and all
input amps only increase volume.
Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

sound/pci/hda/patch_sigmatel.c

@@ -339,6 +339,39 @@ static int stac92xx_aloopback_put(struct snd_kcontrol *kcontrol,
 	return 1;
 }
 
+static int stac92xx_volknob_info(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 127;
+	return 0;
+}
+
+static int stac92xx_volknob_get(struct snd_kcontrol *kcontrol,
+	struct snd_ctl_elem_value *ucontrol)
+{
+	ucontrol->value.integer.value[0] = kcontrol->private_value;
+	return 0;
+}
+
+static int stac92xx_volknob_put(struct snd_kcontrol *kcontrol,
+		struct snd_ctl_elem_value *ucontrol)
+{
+	struct hda_codec *codec = snd_kcontrol_chip(kcontrol);
+
+	if (kcontrol->private_value == ucontrol->value.integer.value[0])
+		return 0;
+
+	kcontrol->private_value = ucontrol->value.integer.value[0];
+
+	snd_hda_codec_write_cache(codec, 0x24, 0,
+		AC_VERB_SET_VOLUME_KNOB_CONTROL,
+			kcontrol->private_value | 0x80);
+	return 1;
+}
+
 
 static struct hda_verb stac9200_core_init[] = {
 	/* set dac0mux for dac converter */
@@ -401,6 +434,17 @@ static struct hda_verb stac9205_core_init[] = {
 		.private_value = verb_read | (verb_write << 16), \
 	}
 
+#define STAC_VOLKNOB \
+	{ \
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER, \
+		.name  = "Master Playback Volume", \
+		.count = 1, \
+		.info  = stac92xx_volknob_info, \
+		.get   = stac92xx_volknob_get, \
+		.put   = stac92xx_volknob_put, \
+		.private_value = 127, \
+	}
+
 
 static struct snd_kcontrol_new stac9200_mixer[] = {
 	HDA_CODEC_VOLUME("Master Playback Volume", 0xb, 0, HDA_OUTPUT),
@@ -423,6 +467,7 @@ static struct snd_kcontrol_new stac925x_mixer[] = {
 /* This needs to be generated dynamically based on sequence */
 static struct snd_kcontrol_new stac922x_mixer[] = {
 	STAC_INPUT_SOURCE,
+	STAC_VOLKNOB,
 	HDA_CODEC_VOLUME("Capture Volume", 0x17, 0x0, HDA_INPUT),
 	HDA_CODEC_MUTE("Capture Switch", 0x17, 0x0, HDA_INPUT),
 	HDA_CODEC_VOLUME("Mux Capture Volume", 0x12, 0x0, HDA_OUTPUT),
@@ -432,6 +477,7 @@ static struct snd_kcontrol_new stac922x_mixer[] = {
 /* This needs to be generated dynamically based on sequence */
 static struct snd_kcontrol_new stac9227_mixer[] = {
 	STAC_INPUT_SOURCE,
+	STAC_VOLKNOB,
 	STAC_ANALOG_LOOPBACK(0xFEB, 0x7EB),
 	HDA_CODEC_VOLUME("Capture Volume", 0x15, 0x0, HDA_OUTPUT),
 	HDA_CODEC_MUTE("Capture Switch", 0x1b, 0x0, HDA_OUTPUT),
@@ -440,6 +486,7 @@ static struct snd_kcontrol_new stac9227_mixer[] = {
 
 static struct snd_kcontrol_new stac927x_mixer[] = {
 	STAC_INPUT_SOURCE,
+	STAC_VOLKNOB,
 	STAC_ANALOG_LOOPBACK(0xFEB, 0x7EB),
 	HDA_CODEC_VOLUME("InMux Capture Volume", 0x15, 0x0, HDA_OUTPUT),
 	HDA_CODEC_VOLUME("InVol Capture Volume", 0x18, 0x0, HDA_INPUT),
@@ -458,6 +505,7 @@ static struct snd_kcontrol_new stac9205_mixer[] = {
 	},
 	STAC_INPUT_SOURCE,
 	STAC_ANALOG_LOOPBACK(0xFE0, 0x7E0),
+	STAC_VOLKNOB,
 	HDA_CODEC_VOLUME("InMux Capture Volume", 0x19, 0x0, HDA_OUTPUT),
 	HDA_CODEC_VOLUME("InVol Capture Volume", 0x1b, 0x0, HDA_INPUT),
 	HDA_CODEC_MUTE("ADCMux Capture Switch", 0x1d, 0x0, HDA_OUTPUT),