sysfs参考代码

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kobject.h>

static ssize_t sysfs_read(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
    return sprintf(buf, "%s
", "sysfs test read,created by vincent");
}

static ssize_t sysfs_write(struct kobject *kobj, struct kobj_attribute *attr, const char *buf,ssize_t  count)
{
    printk("
from user,length=0x%X,content=%s
",count,buf);
    
    if(count)
        return count;
    else
        return 1 ;
}

//static struct kobj_attribute my_sysfs_read = __ATTR(read, S_IRUGO, sysfs_read, NULL);
//static struct kobj_attribute my_sysfs_write = __ATTR(write, S_IWUGO, NULL,sysfs_write);
static struct kobj_attribute my_sysfs_read = __ATTR(aaa, 0664, sysfs_read, NULL);
static struct kobj_attribute my_sysfs_write = __ATTR(bbb, 0664, NULL,sysfs_write);

static struct attribute *my_sysfs_test[] = {
    &my_sysfs_read.attr,
    &my_sysfs_write.attr,
    NULL,
};

static struct attribute_group my_attr_group = {
    .attrs = my_sysfs_test,
};

static int sysfs_status = 0 ;

struct kobject *soc_kobj = NULL;

int my_sysfs_init(void)
{
    int ret = 0;

    printk("my_sysfs_init: %s
",__func__);

    soc_kobj = kobject_create_and_add("my_sysfs", NULL);
    if (!soc_kobj)
        goto err_board_obj;

    ret = sysfs_create_group(soc_kobj, &my_attr_group);
    if (ret)
        goto err_soc_sysfs_create;
    
    sysfs_status = 1;
    /* init func must contain a return vaule,otherwise meet warning when insmod this module */
    return 0;

    sysfs_status = 0;
    
err_soc_sysfs_create:
    kobject_put(soc_kobj);
    sysfs_remove_group(soc_kobj, &my_attr_group);
    printk("
 sysfs_create_group ERROR : %s
",__func__);
    return 0;
    
err_board_obj:
    printk("
 object_create_and_add ERROR : %s
",__func__);
    return 0;
}

void my_sysfs_exit(void)
{
    printk("
 my_sysfs_exit : %s
",__func__);

    if(sysfs_status == 1)
    {
        sysfs_status = 0;
        kobject_put(soc_kobj);
        sysfs_remove_group(soc_kobj, &my_attr_group);
    }
}

MODULE_AUTHOR("derek yi");
MODULE_LICENSE("Dual BSD/GPL");

module_init(my_sysfs_init);
module_exit(my_sysfs_exit);