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Commit 6639b6c2 authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Jaroslav Kysela
Browse files

[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: default avatarClemens Ladisch <clemens@ladisch.de>
parent 84957a8a

sound/usb/usbmixer.c

+98 −3
Original line number Diff line number Diff line
@@ -55,6 +55,8 @@ struct usb_mixer_interface { 
	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_build { 


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 check_matrix_bitmap(unsigned char *bmap, int ich, int och, int num_ou 


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))
@@ -421,9 +426,13 @@ static int add_control_to_empty(mixer_build_t *state, snd_kcontrol_t *kctl) 
	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;

	}

	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 int parse_audio_unit(mixer_build_t *state, int unitid) 


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 @@ static int snd_usb_mixer_controls(struct usb_mixer_interface *mixer) 
	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 @@ int snd_usb_create_mixer(snd_usb_audio_t *chip, int ctrlif) 
#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 @@ int snd_usb_create_mixer(snd_usb_audio_t *chip, int ctrlif) 


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);

}