root/sound/aoa/core/alsa.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Apple Onboard Audio Alsa helpers
 *
 * Copyright 2006 Johannes Berg <johannes@sipsolutions.net>
 */
#include <linux/module.h>
#include "alsa.h"

static int index = -1;
module_param(index, int, 0444);
MODULE_PARM_DESC(index, "index for AOA sound card.");

static struct aoa_card *aoa_card;

int aoa_alsa_init(char *name, struct module *mod, struct device *dev)
{
        struct snd_card *alsa_card;
        int err;

        if (aoa_card)
                /* cannot be EEXIST due to usage in aoa_fabric_register */
                return -EBUSY;

        err = snd_card_new(dev, index, name, mod, sizeof(struct aoa_card),
                           &alsa_card);
        if (err < 0)
                return err;
        aoa_card = alsa_card->private_data;
        aoa_card->alsa_card = alsa_card;
        strscpy(alsa_card->driver, "AppleOnbdAudio");
        strscpy(alsa_card->shortname, name);
        strscpy(alsa_card->longname, name);
        strscpy(alsa_card->mixername, name);
        err = snd_card_register(aoa_card->alsa_card);
        if (err < 0) {
                printk(KERN_ERR "snd-aoa: couldn't register alsa card\n");
                snd_card_free(aoa_card->alsa_card);
                aoa_card = NULL;
                return err;
        }
        return 0;
}

struct snd_card *aoa_get_card(void)
{
        if (aoa_card)
                return aoa_card->alsa_card;
        return NULL;
}
EXPORT_SYMBOL_GPL(aoa_get_card);

void aoa_alsa_cleanup(void)
{
        if (aoa_card) {
                snd_card_free(aoa_card->alsa_card);
                aoa_card = NULL;
        }
}

int aoa_snd_device_new(enum snd_device_type type,
                       void *device_data, const struct snd_device_ops *ops)
{
        struct snd_card *card = aoa_get_card();
        int err;

        if (!card) return -ENOMEM;

        err = snd_device_new(card, type, device_data, ops);
        if (err) {
                printk(KERN_ERR "snd-aoa: failed to create snd device (%d)\n", err);
                return err;
        }
        err = snd_device_register(card, device_data);
        if (err) {
                printk(KERN_ERR "snd-aoa: failed to register "
                                "snd device (%d)\n", err);
                printk(KERN_ERR "snd-aoa: have you forgotten the "
                                "dev_register callback?\n");
                snd_device_free(card, device_data);
        }
        return err;
}
EXPORT_SYMBOL_GPL(aoa_snd_device_new);

int aoa_snd_ctl_add(struct snd_kcontrol* control)
{
        int err;

        if (!aoa_card) return -ENODEV;

        err = snd_ctl_add(aoa_card->alsa_card, control);
        if (err)
                printk(KERN_ERR "snd-aoa: failed to add alsa control (%d)\n",
                       err);
        return err;
}
EXPORT_SYMBOL_GPL(aoa_snd_ctl_add);