bus

#include <linux/device.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/string.h>

MODULE_AUTHOR("David Xie");
MODULE_LICENSE("Dual BSD/GPL");

static char *Version = "$Revision: 1.9 $";

static int my_match(struct device *dev, struct device_driver *driver)
{
    return !strncmp(dev->bus_id, driver->name, strlen(driver->name));
}

static void my_bus_release(struct device *dev)
{
    printk(KERN_DEBUG "my bus release\n");
}

struct device my_bus = {
    .bus_id = "my_bus0",
    .release = my_bus_release
};


struct bus_type my_bus_type = {
    .name = "my_bus",
    .match = my_match,
};

EXPORT_SYMBOL(my_bus);
EXPORT_SYMBOL(my_bus_type);


/*
 * Export a simple attribute.
 */
static ssize_t show_bus_version(struct bus_type *bus, char *buf)
{
    return snprintf(buf, PAGE_SIZE, "%s\n", Version);
}

static BUS_ATTR(version, S_IRUGO, show_bus_version, NULL);


static int __init my_bus_init(void)
{
    int ret;

        /*注册总线*/
    ret = bus_register(&my_bus_type);
    if (ret)
        return ret;

    /*创建属性文件*/
    if (bus_create_file(&my_bus_type, &bus_attr_version))
        printk(KERN_NOTICE "Fail to create version attribute!\n");

    /*注册总线设备*/
    ret = device_register(&my_bus);
    if (ret)
        printk(KERN_NOTICE "Fail to register device:my_bus!\n");

    return ret;
}

static void my_bus_exit(void)
{
    device_unregister(&my_bus);
    bus_unregister(&my_bus_type);
}

module_init(my_bus_init);
module_exit(my_bus_exit);