linux总线设备驱动模型的demo code

#include <linux/module.h> #include <linux/init.h> #include <linux/device.h> #include <linux/string.h> #include "virt_bus_core.h" extern struct device_type virt_client_type; const struct virt_device_id *virt_match_id(const struct virt_device_id *id, const struct virt_client *client) { if (!(id && client)) return NULL; while (id->name[0]) { if (strcmp(client->name, id->name) == 0) return id; id++; } return NULL; } struct virt_client *virt_verify_client(struct device *dev) { return (dev->type == &virt_client_type) ? to_virt_client(dev) : NULL; } static int virt_device_match(struct device *dev, struct device_driver *drv) { struct virt_client *client = virt_verify_client(dev); struct virt_driver *driver; driver = to_virt_driver(drv); /* Finally an virt match */ if (virt_match_id(driver->id_table, client)) return 1; return 0; } static int virt_device_probe(struct device *dev) { struct virt_client *client = virt_verify_client(dev); struct virt_driver *driver; int status; if (!client) return 0; driver = to_virt_driver(dev->driver); if (driver->probe) status = driver->probe(client, virt_match_id(driver->id_table, client)); else status = -EINVAL; return status; } static int virt_device_remove(struct device *dev) { struct virt_client *client = virt_verify_client(dev); struct virt_driver *driver; int status = 0; if (!client || !dev->driver) return 0; driver = to_virt_driver(dev->driver); if (driver->remove) { dev_dbg(dev, "remove\n"); status = driver->remove(client); } return status; } static void virt_client_dev_release(struct device *dev) { kfree(to_virt_client(dev)); } static ssize_t show_name(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%s\n", dev->type == &virt_client_type ? to_virt_client(dev)->name : "unknown"); } static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); static struct attribute *virt_dev_attrs[] = { &dev_attr_name.attr, NULL }; ATTRIBUTE_GROUPS(virt_dev); struct bus_type virt_bus_type = { .name = "virt_bus", .match = virt_device_match, .probe = virt_device_probe, .remove = virt_device_remove, }; EXPORT_SYMBOL_GPL(virt_bus_type); struct device_type virt_client_type = { .name = "virt_client_device", .groups = virt_dev_groups, .release = virt_client_dev_release, }; EXPORT_SYMBOL_GPL(virt_client_type); struct virt_client * virt_register_device(struct virt_board_info const *info) { struct virt_client *client; int status; client = kzalloc(sizeof(*client), GFP_KERNEL); if (!client) return ERR_PTR(-ENOMEM); client->addr = info->addr; strlcpy(client->name, info->type, sizeof(client->name)); client->dev.bus = &virt_bus_type; client->dev.type = &virt_client_type; dev_set_name(&client->dev, "%s-%04x", info->type, info->addr); status = device_register(&client->dev); if (status) goto out_err_silent; printk("device [%s] registered\n", client->name); return client; out_err_silent: kfree(client); return ERR_PTR(status); } EXPORT_SYMBOL_GPL(virt_register_device); void virt_unregister_device(struct virt_client *client) { if (IS_ERR_OR_NULL(client)) return; device_unregister(&client->dev); } EXPORT_SYMBOL_GPL(virt_unregister_device); int virt_register_driver(struct module *owner, struct virt_driver *driver) { int res; /* add the driver to the list of virt drivers in the driver core */ driver->driver.owner = owner; driver->driver.bus = &virt_bus_type; /* When registration returns, the driver core * will have called probe() for all matching-but-unbound devices. */ res = driver_register(&driver->driver); if (res) return res; printk("driver [%s] registered\n", driver->driver.name); return 0; } EXPORT_SYMBOL(virt_register_driver); void virt_unregister_driver(struct virt_driver *driver) { driver_unregister(&driver->driver); printk("driver [%s] unregistered\n", driver->driver.name); } EXPORT_SYMBOL(virt_unregister_driver); static int __init virt_bus_core_init(void) { int retval; retval = bus_register(&virt_bus_type); if (retval) return retval; return 0; } static void __exit virt_bus_core_exit(void) { bus_unregister(&virt_bus_type); } module_init(virt_bus_core_init); module_exit(virt_bus_core_exit); MODULE_LICENSE("GPL");