linux/sound/core/device.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Device management routines
 *  Copyright (c) by Jaroslav Kysela <[email protected]>
 */

#include <linux/slab.h>
#include <linux/time.h>
#include <linux/export.h>
#include <linux/errno.h>
#include <sound/core.h>

/**
 * snd_device_new - create an ALSA device component
 * @card: the card instance
 * @type: the device type, SNDRV_DEV_XXX
 * @device_data: the data pointer of this device
 * @ops: the operator table
 *
 * Creates a new device component for the given data pointer.
 * The device will be assigned to the card and managed together
 * by the card.
 *
 * The data pointer plays a role as the identifier, too, so the
 * pointer address must be unique and unchanged.
 *
 * Return: Zero if successful, or a negative error code on failure.
 */
int snd_device_new(struct snd_card *card, enum snd_device_type type,
		   void *device_data, const struct snd_device_ops *ops)
{ … }
EXPORT_SYMBOL(…);

static void __snd_device_disconnect(struct snd_device *dev)
{ … }

static void __snd_device_free(struct snd_device *dev)
{ … }

static struct snd_device *look_for_dev(struct snd_card *card, void *device_data)
{ … }

/**
 * snd_device_disconnect - disconnect the device
 * @card: the card instance
 * @device_data: the data pointer to disconnect
 *
 * Turns the device into the disconnection state, invoking
 * dev_disconnect callback, if the device was already registered.
 *
 * Usually called from snd_card_disconnect().
 *
 * Return: Zero if successful, or a negative error code on failure or if the
 * device not found.
 */
void snd_device_disconnect(struct snd_card *card, void *device_data)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * snd_device_free - release the device from the card
 * @card: the card instance
 * @device_data: the data pointer to release
 *
 * Removes the device from the list on the card and invokes the
 * callbacks, dev_disconnect and dev_free, corresponding to the state.
 * Then release the device.
 */
void snd_device_free(struct snd_card *card, void *device_data)
{ … }
EXPORT_SYMBOL(…);

static int __snd_device_register(struct snd_device *dev)
{ … }

/**
 * snd_device_register - register the device
 * @card: the card instance
 * @device_data: the data pointer to register
 *
 * Registers the device which was already created via
 * snd_device_new().  Usually this is called from snd_card_register(),
 * but it can be called later if any new devices are created after
 * invocation of snd_card_register().
 *
 * Return: Zero if successful, or a negative error code on failure or if the
 * device not found.
 */
int snd_device_register(struct snd_card *card, void *device_data)
{ … }
EXPORT_SYMBOL(…);

/*
 * register all the devices on the card.
 * called from init.c
 */
int snd_device_register_all(struct snd_card *card)
{ … }

/*
 * disconnect all the devices on the card.
 * called from init.c
 */
void snd_device_disconnect_all(struct snd_card *card)
{ … }

/*
 * release all the devices on the card.
 * called from init.c
 */
void snd_device_free_all(struct snd_card *card)
{ … }

/**
 * snd_device_get_state - Get the current state of the given device
 * @card: the card instance
 * @device_data: the data pointer to release
 *
 * Returns the current state of the given device object.  For the valid
 * device, either @SNDRV_DEV_BUILD, @SNDRV_DEV_REGISTERED or
 * @SNDRV_DEV_DISCONNECTED is returned.
 * Or for a non-existing device, -1 is returned as an error.
 *
 * Return: the current state, or -1 if not found
 */
int snd_device_get_state(struct snd_card *card, void *device_data)
{ … }
EXPORT_SYMBOL_GPL(…);