ALSA: usb-audio: update clock valid control
Make the "clock valid" control a global control instead of a mixer
so that it doesn't appear in mixer applications.
Additionally, remove the check for writeability prohibited by spec, and
Use common code to read the control value.
Tested with a UAC2 Audio device that presents a clock validity
control. The control still shows up in /proc usbmixer but not
in alsamixer.
Signed-off-by: Andrew Chant <achant@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 97ed215..04dab6f 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1235,9 +1235,9 @@
return changed;
}
-/* get the current value from a mixer element */
-static int mixer_ctl_connector_get(struct snd_kcontrol *kcontrol,
- struct snd_ctl_elem_value *ucontrol)
+/* get the boolean value from the master channel of a UAC control */
+static int mixer_ctl_master_bool_get(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol)
{
struct usb_mixer_elem_info *cval = kcontrol->private_data;
int val, err;
@@ -1267,13 +1267,16 @@
.put = NULL,
};
-/* A UAC connector mixer control */
-static struct snd_kcontrol_new usb_connector_ctl_ro = {
+/*
+ * A control which shows the boolean value from reading a UAC control on
+ * the master channel.
+ */
+static struct snd_kcontrol_new usb_bool_master_control_ctl_ro = {
.iface = SNDRV_CTL_ELEM_IFACE_CARD,
.name = "", /* will be filled later manually */
.access = SNDRV_CTL_ELEM_ACCESS_READ,
.info = snd_ctl_boolean_mono_info,
- .get = mixer_ctl_connector_get,
+ .get = mixer_ctl_master_bool_get,
.put = NULL,
};
@@ -1520,12 +1523,18 @@
if (!cval)
return;
snd_usb_mixer_elem_init_std(&cval->head, state->mixer, term->id);
+ /*
+ * The first byte from reading the UAC2_TE_CONNECTOR control returns the
+ * number of channels connected. This boolean ctl will simply report
+ * if any channels are connected or not.
+ * (Audio20_final.pdf Table 5-10: Connector Control CUR Parameter Block)
+ */
cval->control = UAC2_TE_CONNECTOR;
cval->val_type = USB_MIXER_BOOLEAN;
cval->channels = 1; /* report true if any channel is connected */
cval->min = 0;
cval->max = 1;
- kctl = snd_ctl_new1(&usb_connector_ctl_ro, cval);
+ kctl = snd_ctl_new1(&usb_bool_master_control_ctl_ro, cval);
if (!kctl) {
usb_audio_err(state->chip, "cannot malloc kcontrol\n");
kfree(cval);
@@ -1576,13 +1585,9 @@
cval->val_type = USB_MIXER_BOOLEAN;
cval->control = UAC2_CS_CONTROL_CLOCK_VALID;
- if (uac_v2v3_control_is_writeable(hdr->bmControls,
- UAC2_CS_CONTROL_CLOCK_VALID))
- kctl = snd_ctl_new1(&usb_feature_unit_ctl, cval);
- else {
- cval->master_readonly = 1;
- kctl = snd_ctl_new1(&usb_feature_unit_ctl_ro, cval);
- }
+ cval->master_readonly = 1;
+ /* From UAC2 5.2.5.1.2 "Only the get request is supported." */
+ kctl = snd_ctl_new1(&usb_bool_master_control_ctl_ro, cval);
if (!kctl) {
kfree(cval);