#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
struct bus_type my_usb_bus = {
.name = "my_usb", //总线的名字,注册成功后会在/sys/bus/目录下看到
};
#define COUNT_SIZE 100
char data[COUNT_SIZE] = "Hello MikeChen";
/*
内核到用户空间的数据
*/
static ssize_t show_bus_data(struct bus_type * bus, char *buf)
{
return snprintf(buf, COUNT_SIZE, "show Bus Data: %s\n", data);
}
/*
用户空间到内核的数据
*/
static ssize_t store_bus_data(struct bus_type * bus, const char *buf, size_t count)
{
return snprintf(data, COUNT_SIZE, "Store Bus Data: %s\n", buf);
}
/*
注意该宏最终返回bus_attr_version
#define BUS_ATTR(_name, _mode, _show, _store) \
struct bus_attribute bus_attr_##_name = __ATTR(_name, _mode, _show, _store)
*/
static BUS_ATTR(version, S_IRUGO | S_IWUGO, show_bus_data, store_bus_data);
static int __init my_usb_bus_init(void)
{
int ret;
ret = bus_register(&my_usb_bus);
if (ret)
{
printk("Bus register failed!, ret: %d\n", ret);
return ret;
}
printk("Usb init commplete\n");
ret = bus_create_file(&my_usb_bus, &bus_attr_version);
if (ret)
{
printk("Bus Create file failed");
bus_unregister(&my_usb_bus);
return 0;
}
printk("Bus ATTR Create Commplete\n");
return 0;
}
static void __exit my_usb_bus_exit(void)
{
bus_remove_file(&my_usb_bus, &bus_attr_version)
bus_unregister(&my_usb_bus);
printk("Usb Bus exit\n");
}
MODULE_LICENSE("GPL");
MODULE_AUTHOR("MIKE CHEN");
module_init(my_usb_bus_init);
module_exit(my_usb_bus_exit);