/*
* class_simple.c - a "simple" interface for classes for simple char devices.
*
* Copyright (c) 2003-2004 Greg Kroah-Hartman <greg@kroah.com>
* Copyright (c) 2003-2004 IBM Corp.
*
* This file is released under the GPLv2
*
*/
#include <linux/config.h>
#include <linux/device.h>
#include <linux/err.h>
struct class_simple {
struct class class;
};
#define to_class_simple(d) container_of(d, struct class_simple, class)
struct simple_dev {
struct list_head node;
struct class_device class_dev;
};
#define to_simple_dev(d) container_of(d, struct simple_dev, class_dev)
static LIST_HEAD(simple_dev_list);
static DEFINE_SPINLOCK(simple_dev_list_lock);
static void release_simple_dev(struct class_device *class_dev)
{
struct simple_dev *s_dev = to_simple_dev(class_dev);
kfree(s_dev);
}
static void class_simple_release(struct class *class)
{
struct class_simple *cs = to_class_simple(class);
kfree(cs);
}
/**
* class_simple_create - create a struct class_simple structure
* @owner: pointer to the module that is to "own" this struct class_simple
* @name: pointer to a string for the name of this class.
*
* This is used to create a struct class_simple pointer that can then be used
* in calls to class_simple_device_add(). This is used when you do not wish to
* create a full blown class support for a type of char devices.
*
* Note, the pointer created here is to be destroyed when finished by making a
* call to class_simple_destroy().
*/
struct class_simple *class_simple_create(struct module *owner, char *name)
{
struct class_simple *cs;
int retval;
cs = kmalloc(sizeof(*cs), GFP_KERNEL);
if (!cs) {
retval = -ENOMEM;
goto error;
}
memset(cs, 0x00, sizeof(*cs));
cs->class.name = name;
cs->class.class_release = class_simple_release;
cs->class.release = release_simple_dev;
retval = class_register(&cs->class);
if (retval)
goto error;
return cs;
error:
kfree(cs);
return ERR_PTR(retval);
}
EXPORT_SYMBOL(class_simple_create);
/**
* class_simple_destroy - destroys a struct class_simple structure
* @cs: pointer to the struct class_simple that is to be destroyed
*
* Note, the pointer to be destroyed must have been created with a call to
* class_simple_create().
*/
void class_simple_destroy(struct class_simple *cs)
{
if ((cs == NULL) || (IS_ERR(cs)))
return;
class_unregister(&cs->class);
}
EXPORT_SYMBOL(class_simple_destroy);
/**
* class_simple_device_add - adds a class device to sysfs for a character driver
* @cs: pointer to the struct class_simple that this device should be registered to.
* @dev: the dev_t for the device to be added.
* @device: a pointer to a struct device that is assiociated with this class device.
* @fmt: string for the class device's name
*
* This function can be used by simple char device classes that do not
* implement their own class device registration. A struct class_device will
* be created in sysfs, registered to the specified class. A "dev" file will
* be created, showing the dev_t for the device. The pointer to the struct
* class_device will be returned from the call. Any further sysfs files that
* might be required can be created using this pointer.
* Note: the struct class_simple passed to this function must have previously been
* created with a call to class_simple_create().
*/
struct class_device *class_simple_device_add(struct class_simple *cs, dev_t dev, struct device *device, const char *fmt, ...)
{
va_list args;
struct simple_dev *s_dev = NULL;
int retval;
if ((cs == NULL) || (IS_ERR(cs))) {
retval = -ENODEV;
goto error;
}
s_dev = kmalloc(sizeof(*s_dev), GFP_KERNEL);
if (!s_dev) {
retval = -ENOMEM;
goto error;
}
memset(s_dev, 0x00, sizeof(*s_dev));
s_dev->class_dev.devt = dev;
s_dev->class_dev.dev = device;
s_dev->class_dev.class = &cs->class;
va_start(args, fmt);
vsnprintf(s_dev->class_dev.class_id, BUS_ID_SIZE, fmt, args);
va_end(args);
retval = class_device_register(&s_dev->class_dev);
if (retval)
goto error;
spin_lock(&simple_dev_list_lock);
list_add(&s_dev->node, &simple_dev_list);
spin_unlock(&simple_dev_list_lock);
return &s_dev->class_dev;
error:
kfree(s_dev);
return ERR_PTR(retval);
}
EXPORT_SYMBOL(class_simple_device_add);
/**
* class_simple_set_hotplug - set the hotplug callback in the embedded struct class
* @cs: pointer to the struct class_simple to hold the pointer
* @hotplug: function pointer to the hotplug function
*
* Implement and set a hotplug function to add environment variables specific to this
* class on the hotplug event.
*/
int class_simple_set_hotplug(struct class_simple *cs,
int (*hotplug)(struct class_device *dev, char **envp, int num_envp, char *buffer, int buffer_size))
{
if ((cs == NULL) || (IS_ERR(cs)))
return -ENODEV;
cs->class.hotplug = hotplug;
return 0;
}
EXPORT_SYMBOL(class_simple_set_hotplug);
/**
* class_simple_device_remove - removes a class device that was created with class_simple_device_add()
* @dev: the dev_t of the device that was previously registered.
*
* This call unregisters and cleans up a class device that was created with a
* call to class_device_simple_add()
*/
void class_simple_device_remove(dev_t dev)
{
struct simple_dev *s_dev = NULL;
int found = 0;
spin_lock(&simple_dev_list_lock);
list_for_each_entry(s_dev, &simple_dev_list, node) {
if (s_dev->class_dev.devt == dev) {
found = 1;
break;
}
}
if (found) {
list_del(&s_dev->node);
spin_unlock(&simple_dev_list_lock);
class_device_unregister(&s_dev->class_dev);
} else {
spin_unlock(&simple_dev_list_lock);
}
}
EXPORT_SYMBOL(class_simple_device_remove);
