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sysfsexample.c
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sysfsexample.c
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//http://godandme.wordpress.com/2011/04/05/how-to-make-a-sysfs-entry/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
struct my_attr {
struct attribute attr;
int value;
};
static struct my_attr notify = {
.attr.name="notify",
.attr.mode = 0644,
.value = 0,
};
static struct my_attr trigger = {
.attr.name="trigger",
.attr.mode = 0644,
.value = 0,
};
static struct attribute * myattr[] = {
¬ify.attr,
&trigger.attr,
NULL
};
static ssize_t default_show(struct kobject *kobj, struct attribute *attr,
char *buf)
{
struct my_attr *a = container_of(attr, struct my_attr, attr);
return scnprintf(buf, PAGE_SIZE, "%d\n", a->value);
}
static struct kobject *mykobj;
static ssize_t default_store(struct kobject *kobj, struct attribute *attr,
const char *buf, size_t len)
{
struct my_attr *a = container_of(attr, struct my_attr, attr);
sscanf(buf, "%d", &a->value);
notify.value = a->value;
printk("sysfs_notify store %s = %d\n", a->attr.name, a->value);
sysfs_notify(mykobj, NULL, "notify");
return sizeof(int);
}
static struct sysfs_ops myops = {
.show = default_show,
.store = default_store,
};
static struct kobj_type mytype = {
.sysfs_ops = &myops,
.default_attrs = myattr,
};
static struct kobject *mykobj;
static int __init sysfsexample_module_init(void)
{
int err = -1;
printk("sysfs_notify init\n");
mykobj = kzalloc(sizeof(*mykobj), GFP_KERNEL);
if (mykobj) {
kobject_init(mykobj, &mytype);
if (kobject_add(mykobj, NULL, "%s", "sysfs_sample")) {
err = -1;
printk("sysfs_notify: kobject_add() failed\n");
kobject_put(mykobj);
mykobj = NULL;
}
err = 0;
}
return err;
}
static void __exit sysfsexample_module_exit(void)
{
if (mykobj) {
kobject_put(mykobj);
kfree(mykobj);
}
printk("sysfs_notify exit\n");
}
module_init(sysfsexample_module_init);
module_exit(sysfsexample_module_exit);
MODULE_LICENSE("GPL");