有时我们需要在/sys下面创建一些目录， 下面给出了一个示例。 在加载驱动模块后， 在/sys下面会创建一个名为sysfs_demo的目录，并在其中在创建几个文件和目录。
[root@tiny4412 mnt]# ls -R /sys/sysfs_demo/
/sys/sysfs_demo/:
node_one node_two sysfs_demo_2 /sys/sysfs_demo/sysfs_demo_2:
node_four node_three
这里用到的两个函数分别是： kobject_create_and_add 和 sysfs_create_group。前一个函数用于在/sys下面创建目录， 后一个函数用于创建文件。
示例驱动：
#define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__ #include <linux/init.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/device.h> static struct kobject *k_obj = NULL;
static struct kobject *k_obj_2 = NULL; static char node_one_buf[] = {}; static ssize_t sysfs_demo_show_node_one(struct kobject *kobj, struct kobj_attribute *attr, char * buf)
{
pr_info("enter, node: %s\n", attr->attr.name);
return sprintf(buf, "%s: %s\n", attr->attr.name, node_one_buf);
} static ssize_t sysfs_demo_store_node_one(struct kobject *kobj, struct kobj_attribute *attr, const char * buf, size_t n)
{
pr_info("enter, node: %s\n", attr->attr.name); sprintf(node_one_buf, "%s", buf); return n;
} static struct kobj_attribute node_one_attribute =
__ATTR(node_one, S_IWUSR|S_IRUGO, sysfs_demo_show_node_one, sysfs_demo_store_node_one); static ssize_t sysfs_demo_show_node_two(struct kobject *kobj, struct kobj_attribute *attr, char * buf)
{ return sprintf(buf, "%s\n", attr->attr.name);
} static struct kobj_attribute node_two_attribute =
__ATTR(node_two, S_IWUSR|S_IRUGO, sysfs_demo_show_node_two, NULL); static struct attribute *sysfs_demo_attributes[] = {
&node_one_attribute.attr,
&node_two_attribute.attr,
NULL
}; static const struct attribute_group sysfs_demo_attr_group = {
.attrs = sysfs_demo_attributes,
}; static char node_three_buf[] = {}; static ssize_t sysfs_demo_show_node_three(struct kobject *kobj, struct kobj_attribute *attr, char * buf)
{
pr_info("enter, node: %s\n", attr->attr.name);
return sprintf(buf, "%s: %s\n", attr->attr.name, node_three_buf);
} static ssize_t sysfs_demo_store_node_three(struct kobject *kobj, struct kobj_attribute *attr, const char * buf, size_t n)
{
pr_info("enter, node: %s\n", attr->attr.name); sprintf(node_three_buf, "%s", buf); return n;
} static struct kobj_attribute node_three_attribute =
__ATTR(node_three, S_IWUSR|S_IRUGO, sysfs_demo_show_node_three, sysfs_demo_store_node_three); static ssize_t sysfs_demo_show_node_four(struct kobject *kobj, struct kobj_attribute *attr, char * buf)
{ return sprintf(buf, "%s\n", attr->attr.name);
} static struct kobj_attribute node_four_attribute =
__ATTR(node_four, S_IWUSR|S_IRUGO, sysfs_demo_show_node_four, NULL); static struct attribute *sysfs_demo2_attributes[] = {
&node_three_attribute.attr,
&node_four_attribute.attr,
NULL
}; static const struct attribute_group sysfs_demo2_attr_group = {
.attrs = sysfs_demo2_attributes,
}; static int __init sysfs_demo_init(void)
{
if ((k_obj = kobject_create_and_add("sysfs_demo", NULL)) == NULL ) {
pr_err("sysfs_demo sys node create error \n");
goto out;
} if(sysfs_create_group(k_obj, &sysfs_demo_attr_group) ) {
pr_err("sysfs_create_group failed\n");
goto out2;
} if ((k_obj_2 = kobject_create_and_add("sysfs_demo_2", k_obj)) == NULL ) {
pr_err("hwinfo sys node create error \n");
goto out3;
} if(sysfs_create_group(k_obj_2, &sysfs_demo2_attr_group) ) {
pr_err("sysfs_create_group failed\n");
goto out4;
} pr_info("enter.\n");
return ;
out4:
kobject_put(k_obj_2);
out3:
sysfs_remove_group(k_obj, &sysfs_demo_attr_group);
out2:
kobject_put(k_obj);
out:
return -;
}
module_init(sysfs_demo_init); static void __exit sysfs_demo_exit(void)
{
pr_info("enter.\n"); if (k_obj) {
sysfs_remove_group(k_obj, &sysfs_demo_attr_group);
if (k_obj_2) {
sysfs_remove_group(k_obj_2, &sysfs_demo2_attr_group);
kobject_put(k_obj_2);
}
kobject_put(k_obj);
} }
module_exit(sysfs_demo_exit); MODULE_LICENSE("GPL");