linux/drivers/counter/counter-core.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Generic Counter interface
 * Copyright (C) 2020 William Breathitt Gray
 */
#include <linux/cdev.h>
#include <linux/counter.h>
#include <linux/device.h>
#include <linux/device/bus.h>
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/gfp.h>
#include <linux/idr.h>
#include <linux/init.h>
#include <linux/kdev_t.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/wait.h>

#include "counter-chrdev.h"
#include "counter-sysfs.h"

#define COUNTER_NAME …

/* Provides a unique ID for each counter device */
static DEFINE_IDA(counter_ida);

struct counter_device_allochelper { … };

static void counter_device_release(struct device *dev)
{ … }

static const struct device_type counter_device_type = …;

static const struct bus_type counter_bus_type = …;

static dev_t counter_devt;

/**
 * counter_priv - access counter device private data
 * @counter: counter device
 *
 * Get the counter device private data
 */
void *counter_priv(const struct counter_device *const counter)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

/**
 * counter_alloc - allocate a counter_device
 * @sizeof_priv: size of the driver private data
 *
 * This is part one of counter registration. The structure is allocated
 * dynamically to ensure the right lifetime for the embedded struct device.
 *
 * If this succeeds, call counter_put() to get rid of the counter_device again.
 */
struct counter_device *counter_alloc(size_t sizeof_priv)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

void counter_put(struct counter_device *counter)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

/**
 * counter_add - complete registration of a counter
 * @counter: the counter to add
 *
 * This is part two of counter registration.
 *
 * If this succeeds, call counter_unregister() to get rid of the counter_device again.
 */
int counter_add(struct counter_device *counter)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

/**
 * counter_unregister - unregister Counter from the system
 * @counter:	pointer to Counter to unregister
 *
 * The Counter is unregistered from the system.
 */
void counter_unregister(struct counter_device *const counter)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

static void devm_counter_release(void *counter)
{ … }

static void devm_counter_put(void *counter)
{ … }

/**
 * devm_counter_alloc - allocate a counter_device
 * @dev: the device to register the release callback for
 * @sizeof_priv: size of the driver private data
 *
 * This is the device managed version of counter_add(). It registers a cleanup
 * callback to care for calling counter_put().
 */
struct counter_device *devm_counter_alloc(struct device *dev, size_t sizeof_priv)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

/**
 * devm_counter_add - complete registration of a counter
 * @dev: the device to register the release callback for
 * @counter: the counter to add
 *
 * This is the device managed version of counter_add(). It registers a cleanup
 * callback to care for calling counter_unregister().
 */
int devm_counter_add(struct device *dev,
		     struct counter_device *const counter)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

#define COUNTER_DEV_MAX …

static int __init counter_init(void)
{ … }

static void __exit counter_exit(void)
{ … }

subsys_initcall(counter_init);
module_exit(counter_exit);

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;