root/sound/soc/sdca/sdca_function_device.c
// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
// Copyright(c) 2024 Intel Corporation.

/*
 * SDCA Function Device management
 */

#include <linux/acpi.h>
#include <linux/module.h>
#include <linux/auxiliary_bus.h>
#include <linux/soundwire/sdw.h>
#include <sound/sdca.h>
#include <sound/sdca_function.h>
#include "sdca_function_device.h"

/*
 * A SoundWire device can have multiple SDCA functions identified by
 * their type and ADR. there can be multiple SoundWire devices per
 * link, or multiple devices spread across multiple links. An IDA is
 * required to identify each instance.
 */
static DEFINE_IDA(sdca_function_ida);

static void sdca_dev_release(struct device *dev)
{
        struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
        struct sdca_dev *sdev = auxiliary_dev_to_sdca_dev(auxdev);

        ida_free(&sdca_function_ida, auxdev->id);
        kfree(sdev);
}

/* alloc, init and add link devices */
static struct sdca_dev *sdca_dev_register(struct device *parent,
                                          struct sdca_function_desc *function_desc)
{
        struct sdca_dev *sdev;
        struct auxiliary_device *auxdev;
        int ret;
        int rc;

        sdev = kzalloc_obj(*sdev);
        if (!sdev)
                return ERR_PTR(-ENOMEM);

        auxdev = &sdev->auxdev;
        auxdev->name = function_desc->name;
        auxdev->dev.parent = parent;
        auxdev->dev.fwnode = function_desc->node;
        auxdev->dev.release = sdca_dev_release;

        sdev->function.desc = function_desc;

        rc = ida_alloc(&sdca_function_ida, GFP_KERNEL);
        if (rc < 0) {
                kfree(sdev);
                return ERR_PTR(rc);
        }
        auxdev->id = rc;

        /* now follow the two-step init/add sequence */
        ret = auxiliary_device_init(auxdev);
        if (ret < 0) {
                dev_err(parent, "failed to initialize SDCA function dev %s\n",
                        function_desc->name);
                ida_free(&sdca_function_ida, auxdev->id);
                kfree(sdev);
                return ERR_PTR(ret);
        }

        ret = auxiliary_device_add(auxdev);
        if (ret < 0) {
                dev_err(parent, "failed to add SDCA function dev %s\n",
                        sdev->auxdev.name);
                /* sdev will be freed with the put_device() and .release sequence */
                auxiliary_device_uninit(&sdev->auxdev);
                return ERR_PTR(ret);
        }

        return sdev;
}

static void sdca_dev_unregister(struct sdca_dev *sdev)
{
        auxiliary_device_delete(&sdev->auxdev);
        auxiliary_device_uninit(&sdev->auxdev);
}

int sdca_dev_register_functions(struct sdw_slave *slave)
{
        struct sdca_device_data *sdca_data = &slave->sdca_data;
        int i;

        for (i = 0; i < sdca_data->num_functions; i++) {
                struct sdca_dev *func_dev;

                func_dev = sdca_dev_register(&slave->dev,
                                             &sdca_data->function[i]);
                if (IS_ERR(func_dev))
                        return PTR_ERR(func_dev);

                sdca_data->function[i].func_dev = func_dev;
        }

        return 0;
}
EXPORT_SYMBOL_NS(sdca_dev_register_functions, "SND_SOC_SDCA");

void sdca_dev_unregister_functions(struct sdw_slave *slave)
{
        struct sdca_device_data *sdca_data = &slave->sdca_data;
        int i;

        for (i = 0; i < sdca_data->num_functions; i++)
                sdca_dev_unregister(sdca_data->function[i].func_dev);
}
EXPORT_SYMBOL_NS(sdca_dev_unregister_functions, "SND_SOC_SDCA");