input输入子系统源码部分函数分析
/* *源文件目录： */drivers/input/input.c */入口函数：static int __init input_init(void)1、err = class_register(&input_class);/* class设备节点生成 */2、 err = input_proc_init();/* 为添加到proc文件系统的设备节点文件做一些初始化工作 */3、 err = register_chrdev(INPUT_MAJOR, "input", &input_fops);/* 注册为字符型驱动 *//* * input_fops结构体分析 */ static const struct file_operations input_fops = {.owner = THIS_MODULE,/* 模块所属者 */.open = input_open_file,/* 打开操作函数 */.llseek = noop_llseek,/* 绕过llseek操作 */};/* * input_open_file函数分析 */static int input_open_file(struct inode *inode, struct file *file)1. struct input_handler *handler;/* handler声明 *//* * input_hanler结构体： * struct input_handler {void *private;void (*event)(struct input_handle *handle, unsigned int type, unsigned int code, int value);bool (*filter)(struct input_handle *handle, unsigned int type, unsigned int code, int value);bool (*match)(struct input_handler *handler, struct input_dev *dev);int (*connect)(struct input_handler *handler, struct input_dev *dev, const struct input_device_id *id);void (*disconnect)(struct input_handle *handle);void (*start)(struct input_handle *handle);const struct file_operations *fops;int minor;const char *name;const struct input_device_id *id_table; *struct list_headh_list; *struct list_headnode; *}; */ 2. const struct file_operations *old_fops, *new_fops = NULL;/* file_operations结构体声明 */ 3. err = mutex_lock_interruptible(&input_mutex);/* 上互斥锁操作 */ 4. handler = input_table[iminor(inode) >> 5];/* input_table链表中第iminor(inode) >> 5节点的handler */ 5. if (handler)/* 是否存在此handler */new_fops = fops_get(handler->fops);/* 存在内容则取出此handler的fops结构体赋予new_fops */ 6. mutex_unlock(&input_mutex);/* 解除互斥锁 */ 7. old_fops = file->f_op;file->f_op = new_fops;/* 交换file_operation，使input设备可使用相应的操作函数 */8. err = new_fops->open(inode, file);/* 使用对于的打开函数 */9. fops_put(old_fops);/* 释放old_fops *//* * input_register_device函数分析 */int input_register_device(struct input_dev *dev);1. static atomic_t input_no = ATOMIC_INIT(0);/* 原子变量初始化 */2. struct input_handler *handler;/* 新handler声明 */3. /* Every input device generates EV_SYN/SYN_REPORT events. *//* 设置dev结构体 */ __set_bit(EV_SYN, dev->evbit); /* KEY_RESERVED is not supposed to be transmitted to userspace. */ __clear_bit(KEY_RESERVED, dev->keybit); /* Make sure that bitmasks not mentioned in dev->evbit are clean. */ input_cleanse_bitmasks(dev);4. init_timer(&dev->timer);/* 初始化一个定时器 */5. error = device_add(&dev->dev);/* 添加设备 *//* *device_add函数分析 */int device_add(struct device *dev) 1. dev = get_device(dev);/* 获取dev的kobj */ struct device *get_device(struct device *dev); \--->return dev ? to_dev(kobject_get(&dev->kobj)) : NULL; 2. parent = get_device(dev->parent);/* 获取父类驱动的kobj */ setup_parent(dev, parent);/* 启动父类驱动 */3. error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);/* 将dev->kobj, dev->kobj.parent添加至内核中 */ 6. error = mutex_lock_interruptible(&input_mutex);/* 上互斥锁 */7. list_add_tail(&dev->node, &input_dev_list);/* 添加到input_dev_list队列中 */8. list_for_each_entry(handler, &input_handler_list, node)input_attach_handler(dev, handler);/* 遍历每个节点 */9. input_wakeup_procfs_readers();/* 唤醒procfs_readers */10. mutex_unlock(&input_mutex);/* 解除互斥锁 */ /* * input_register_handler函数分析 */int input_register_handler(struct input_handler *handler)；1. struct input_dev *dev;/* input_dev结构体指针声明 */2. retval = mutex_lock_interruptible(&input_mutex);/* 上互斥锁 */3. INIT_LIST_HEAD(&handler->h_list);/* 初始化list的前级与后继指针都指向list */4. if (handler->fops != NULL) {/* 判断是否有值handler->fops */if (input_table[handler->minor >> 5]) {/* 判断input_table[handler->minor >> 5]节点是否有值 */retval = -EBUSY;goto out;}input_table[handler->minor >> 5] = handler;/* 将handler添加到input_table[handler->minor >> 5]节点上 */}5. list_add_tail(&handler->node, &input_handler_list);/* 将handler->node放入到队列中 */6. list_for_each_entry(dev, &input_dev_list, node)input_attach_handler(dev, handler);/* 遍历每个节点 */7. input_wakeup_procfs_readers();/* 唤醒procfs_readers *//* * input_allocate_device函数分析 */struct input_dev *input_allocate_device(void); 1. struct input_dev *dev;/* input_dev结构体声明 */ 2. dev = kzalloc(sizeof(struct input_dev), GFP_KERNEL);/* input_dev结构体空间分配 */ /* * 分析kzalloc函数 */ static inline void *kzalloc(size_t size, gfp_t flags) \-->return kmalloc(size, flags | __GFP_ZERO); 3. if (dev) {/* 初始化dev的成员变量 */dev->dev.type = &input_dev_type;dev->dev.class = &input_class;device_initialize(&dev->dev);/* * device_initialize函数 */ void device_initialize(struct device *dev){dev->kobj.kset = devices_kset;kobject_init(&dev->kobj, &device_ktype);INIT_LIST_HEAD(&dev->dma_pools);mutex_init(&dev->mutex);lockdep_set_novalidate_class(&dev->mutex);spin_lock_init(&dev->devres_lock);INIT_LIST_HEAD(&dev->devres_head);device_pm_init(dev);set_dev_node(dev, -1);}/* * 互斥锁初始化 */mutex_init(&dev->mutex);/* * 自旋锁初始化 */spin_lock_init(&dev->event_lock);INIT_LIST_HEAD(&dev->h_list);INIT_LIST_HEAD(&dev->node);__module_get(THIS_MODULE);}/* * input_attach_handler函数分析 */static int input_attach_handler(struct input_dev *dev, struct input_handler *handler)；1. id = input_match_device(handler, dev);/* 比较handler与dev的id */2. error = handler->connect(handler, dev, id);/* 调用相应handler的connet函数 *//* * input_register_handle函数分析 */int input_register_handle(struct input_handle *handle)1. error = mutex_lock_interruptible(&dev->mutex);/* 上互斥锁 */2. if (handler->filter)/* 使dev->h_list指向handle->d_node */list_add_rcu(&handle->d_node, &dev->h_list); elselist_add_tail_rcu(&handle->d_node, &dev->h_list);3. mutex_unlock(&dev->mutex);/* 解除互斥锁 */14. list_add_tail_rcu(&handle->h_node, &handler->h_list);/* 使handler->h_list指向handle->h_node */