[ALSA] usb-audio - add mixer control notifications
USB generic driver
Add support for the optional status interrupt endpoint in audio control
interfaces, and translate USB status notifications into ALSA mixer
control notifications.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
diff --git a/sound/usb/usbmixer.c b/sound/usb/usbmixer.c
index 7bbcceb..dd045ea 100644
--- a/sound/usb/usbmixer.c
+++ b/sound/usb/usbmixer.c
@@ -55,6 +55,8 @@
unsigned int ctrlif;
struct list_head list;
unsigned int ignore_ctl_error;
+ struct urb *urb;
+ usb_mixer_elem_info_t **id_elems; /* array[256], indexed by unit id */
};
@@ -83,13 +85,15 @@
struct usb_mixer_elem_info {
struct usb_mixer_interface *mixer;
+ usb_mixer_elem_info_t *next_id_elem; /* list of controls with same id */
+ snd_ctl_elem_id_t *elem_id;
unsigned int id;
unsigned int control; /* CS or ICN (high byte) */
unsigned int cmask; /* channel mask bitmap: 0 = master */
int channels;
int val_type;
int min, max, res;
- unsigned int initialized: 1;
+ u8 initialized;
};
@@ -414,6 +418,7 @@
static int add_control_to_empty(mixer_build_t *state, snd_kcontrol_t *kctl)
{
+ usb_mixer_elem_info_t *cval = kctl->private_data;
int err;
while (snd_ctl_find_id(state->chip->card, &kctl->id))
@@ -421,8 +426,12 @@
if ((err = snd_ctl_add(state->chip->card, kctl)) < 0) {
snd_printd(KERN_ERR "cannot add control (err = %d)\n", err);
snd_ctl_free_one(kctl);
+ return err;
}
- return err;
+ cval->elem_id = &kctl->id;
+ cval->next_id_elem = state->mixer->id_elems[cval->id];
+ state->mixer->id_elems[cval->id] = cval;
+ return 0;
}
@@ -1522,6 +1531,11 @@
static void snd_usb_mixer_free(struct usb_mixer_interface *mixer)
{
+ kfree(mixer->id_elems);
+ if (mixer->urb) {
+ kfree(mixer->urb->transfer_buffer);
+ usb_free_urb(mixer->urb);
+ }
kfree(mixer);
}
@@ -1580,6 +1594,76 @@
return 0;
}
+static void snd_usb_mixer_notify_id(struct usb_mixer_interface *mixer,
+ int unitid)
+{
+ usb_mixer_elem_info_t *info;
+
+ for (info = mixer->id_elems[unitid]; info; info = info->next_id_elem)
+ snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
+ info->elem_id);
+}
+
+static void snd_usb_mixer_status_complete(struct urb *urb, struct pt_regs *regs)
+{
+ struct usb_mixer_interface *mixer = urb->context;
+
+ if (urb->status == 0) {
+ u8 *buf = urb->transfer_buffer;
+ int i;
+
+ for (i = urb->actual_length; i >= 2; buf += 2, i -= 2) {
+ snd_printd(KERN_DEBUG "status interrupt: %02x %02x\n",
+ buf[0], buf[1]);
+ /* ignore any notifications not from the control interface */
+ if ((buf[0] & 0x0f) != 0)
+ continue;
+ if (!(buf[0] & 0x40))
+ snd_usb_mixer_notify_id(mixer, buf[1]);
+ }
+ }
+ if (urb->status != -ENOENT && urb->status != -ECONNRESET) {
+ urb->dev = mixer->chip->dev;
+ usb_submit_urb(urb, GFP_ATOMIC);
+ }
+}
+
+/* create the handler for the optional status interrupt endpoint */
+static int snd_usb_mixer_status_create(struct usb_mixer_interface *mixer)
+{
+ struct usb_host_interface *hostif;
+ struct usb_endpoint_descriptor *ep;
+ void *transfer_buffer;
+ int buffer_length;
+ unsigned int epnum;
+
+ hostif = &usb_ifnum_to_if(mixer->chip->dev, mixer->ctrlif)->altsetting[0];
+ /* we need one interrupt input endpoint */
+ if (get_iface_desc(hostif)->bNumEndpoints < 1)
+ return 0;
+ ep = get_endpoint(hostif, 0);
+ if ((ep->bEndpointAddress & USB_ENDPOINT_DIR_MASK) != USB_DIR_IN ||
+ (ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) != USB_ENDPOINT_XFER_INT)
+ return 0;
+
+ epnum = ep->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
+ buffer_length = le16_to_cpu(ep->wMaxPacketSize);
+ transfer_buffer = kmalloc(buffer_length, GFP_KERNEL);
+ if (!transfer_buffer)
+ return -ENOMEM;
+ mixer->urb = usb_alloc_urb(0, GFP_KERNEL);
+ if (!mixer->urb) {
+ kfree(transfer_buffer);
+ return -ENOMEM;
+ }
+ usb_fill_int_urb(mixer->urb, mixer->chip->dev,
+ usb_rcvintpipe(mixer->chip->dev, epnum),
+ transfer_buffer, buffer_length,
+ snd_usb_mixer_status_complete, mixer, ep->bInterval);
+ usb_submit_urb(mixer->urb, GFP_KERNEL);
+ return 0;
+}
+
int snd_usb_create_mixer(snd_usb_audio_t *chip, int ctrlif)
{
static snd_device_ops_t dev_ops = {
@@ -1598,8 +1682,14 @@
#ifdef IGNORE_CTL_ERROR
mixer->ignore_ctl_error = 1;
#endif
+ mixer->id_elems = kcalloc(256, sizeof(*mixer->id_elems), GFP_KERNEL);
+ if (!mixer->id_elems) {
+ kfree(mixer);
+ return -ENOMEM;
+ }
- if ((err = snd_usb_mixer_controls(mixer)) < 0) {
+ if ((err = snd_usb_mixer_controls(mixer)) < 0 ||
+ (err = snd_usb_mixer_status_create(mixer)) < 0) {
snd_usb_mixer_free(mixer);
return err;
}
@@ -1615,4 +1705,9 @@
void snd_usb_mixer_disconnect(struct list_head *p)
{
+ struct usb_mixer_interface *mixer;
+
+ mixer = list_entry(p, struct usb_mixer_interface, list);
+ if (mixer->urb)
+ usb_kill_urb(mixer->urb);
}