ALSA: hdspm - Introduce generic AIO tristate control

AIO cards offer at least four individual settings options with three
states each. Those settings are represented as two bits in the settings
register with the following meaning:

   0*some_base_bit --> Option value 0
   1*some_base_bit --> Option value 1
   2*some_base_bit --> Option value 2
   3*some_base_bit --> mask to select the two involved bits

This patch adds a generic ALSA control macro for such a value-to-bit
pattern mapping. It will be used in a later commit to expose four new
controls.
Signed-off-by: NAdrian Knoth <adi@drcomp.erfurt.thur.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/pci/rme9652/hdspm.c

@@ -3348,6 +3348,84 @@ static int snd_hdspm_put_qs_wire(struct snd_kcontrol *kcontrol,
 	return change;
 }
 
+#define HDSPM_CONTROL_TRISTATE(xname, xindex) \
+{	.iface = SNDRV_CTL_ELEM_IFACE_MIXER, \
+	.name = xname, \
+	.private_value = xindex, \
+	.info = snd_hdspm_info_tristate, \
+	.get = snd_hdspm_get_tristate, \
+	.put = snd_hdspm_put_tristate \
+}
+
+static int hdspm_tristate(struct hdspm *hdspm, u32 regmask)
+{
+	u32 reg = hdspm->settings_register & (regmask * 3);
+	return reg / regmask;
+}
+
+static int hdspm_set_tristate(struct hdspm *hdspm, int mode, u32 regmask)
+{
+	hdspm->settings_register &= ~(regmask * 3);
+	hdspm->settings_register |= (regmask * mode);
+	hdspm_write(hdspm, HDSPM_WR_SETTINGS, hdspm->settings_register);
+
+	return 0;
+}
+
+static int snd_hdspm_info_tristate(struct snd_kcontrol *kcontrol,
+				       struct snd_ctl_elem_info *uinfo)
+{
+	u32 regmask = kcontrol->private_value;
+
+	static char *texts_spdif[] = { "Optical", "Coaxial", "Internal" };
+	static char *texts_levels[] = { "Hi Gain", "+4 dBu", "-10 dBV" };
+
+	switch (regmask) {
+	case HDSPM_c0_Input0:
+		ENUMERATED_CTL_INFO(uinfo, texts_spdif);
+		break;
+	default:
+		ENUMERATED_CTL_INFO(uinfo, texts_levels);
+		break;
+	}
+	return 0;
+}
+
+static int snd_hdspm_get_tristate(struct snd_kcontrol *kcontrol,
+				      struct snd_ctl_elem_value *ucontrol)
+{
+	struct hdspm *hdspm = snd_kcontrol_chip(kcontrol);
+	u32 regmask = kcontrol->private_value;
+
+	spin_lock_irq(&hdspm->lock);
+	ucontrol->value.enumerated.item[0] = hdspm_tristate(hdspm, regmask);
+	spin_unlock_irq(&hdspm->lock);
+	return 0;
+}
+
+static int snd_hdspm_put_tristate(struct snd_kcontrol *kcontrol,
+				      struct snd_ctl_elem_value *ucontrol)
+{
+	struct hdspm *hdspm = snd_kcontrol_chip(kcontrol);
+	u32 regmask = kcontrol->private_value;
+	int change;
+	int val;
+
+	if (!snd_hdspm_use_is_exclusive(hdspm))
+		return -EBUSY;
+	val = ucontrol->value.integer.value[0];
+	if (val < 0)
+		val = 0;
+	if (val > 2)
+		val = 2;
+
+	spin_lock_irq(&hdspm->lock);
+	change = val != hdspm_tristate(hdspm, regmask);
+	hdspm_set_tristate(hdspm, val, regmask);
+	spin_unlock_irq(&hdspm->lock);
+	return change;
+}
+
 #define HDSPM_MADI_SPEEDMODE(xname, xindex) \
 {	.iface = SNDRV_CTL_ELEM_IFACE_MIXER, \
 	.name = xname, \