一個(gè)鼠標(biāo)驅(qū)動(dòng)程序的分析(/driver/input/mouse/amimouse.c)

一：Input設(shè)備驅(qū)動(dòng)，(我稱為虛擬輸入設(shè)備)//drivers/input/input.c文件
	 input設(shè)備是一種字符設(shè)備在模塊初始化時(shí)創(chuàng)建設(shè)備類"input",注冊(cè)Input字符設(shè)備，input的操作函數(shù)只有Open函數(shù)。當(dāng)打開特
	 定設(shè)備時(shí)才將特定的設(shè)備操作函數(shù)
	 static struct file_operations input_fops = {
	.owner = THIS_MODULE,
		.open = input_open_file,
	};
函數(shù)調(diào)用如下：
“/input/input . c”
input_init()//這是虛擬輸入設(shè)備的入口，既模塊加載時(shí)調(diào)用
{
	class_simple_create(THIS_MODULE,"input");//創(chuàng)建設(shè)備類
	input_proc_init()//創(chuàng)建proc下的文件節(jié)點(diǎn)
		retval = register_chrdev(INPUT_MAJOR, "input", &input_fops);//注冊(cè)字符設(shè)備驅(qū)動(dòng)程序，在系統(tǒng)字符設(shè)備數(shù)組中添加一個(gè)字符設(shè)
	
	備，主設(shè)備號(hào)為INPUT—MAJOR，操作函數(shù)集為input_fops，在特殊文件打開時(shí)會(huì)根據(jù)文件的節(jié)點(diǎn)結(jié)構(gòu)INODE中的主設(shè)備
		
		號(hào)在系統(tǒng)字符設(shè)備數(shù)組中搜索主設(shè)備號(hào)相同的字符設(shè)備驅(qū)動(dòng)程序的操作函數(shù)集并將此操作函數(shù)集付給FILE結(jié)構(gòu)的操
		
		作函數(shù)集指針f_ops并執(zhí)行該函數(shù)集中的打開操作。。對(duì)于本input類設(shè)備即為input_fops中的input_open_file
		
		devfs_mk_dir("input")//在設(shè)備目錄"/dev"下創(chuàng)建devfs文件系統(tǒng)的"input"目錄，以后的具體輸入設(shè)備也將在這個(gè)目錄下建立
		
		特殊設(shè)備文件，當(dāng)打開該特殊文件時(shí)即對(duì)設(shè)備進(jìn)行操作
}
當(dāng)打開具體文件時(shí)既執(zhí)行input_ipen_file
此函數(shù)會(huì)尋到具體設(shè)備的文件操作函數(shù)集并付給file->f_op（這是一個(gè)文件的操作函數(shù)集，當(dāng)系統(tǒng)打開一個(gè)文件時(shí)即產(chǎn)生一個(gè)file結(jié)構(gòu)
對(duì)該文件的操作都通過file中的f_opes 如讀取即調(diào)用FILE->f_op->read等


二：輸入驅(qū)動(dòng)器，輸入驅(qū)動(dòng)器是指一類的輸入設(shè)備（比如鼠標(biāo)輸入驅(qū)動(dòng)器，鍵盤輸入驅(qū)動(dòng)器等等）
這里說的是鼠標(biāo)輸入驅(qū)動(dòng)器。。（我也稱之為虛擬鼠標(biāo)驅(qū)動(dòng)器，因?yàn)樗⒉煌瓿烧嬲挠布嚓P(guān)的鼠標(biāo)驅(qū)動(dòng)，
真正的硬件IO驅(qū)動(dòng)要在device中完成）他的描述結(jié)構(gòu)是
struct input_handler {
	
	void *private;//私有數(shù)據(jù)
	
	void (*event)(struct input_handle *handle, unsigned int type, unsigned int code, int value);//響應(yīng)輸入事件的函數(shù)
	struct input_handle* (*connect)(struct input_handler *handler, struct input_dev *dev, struct input_device_id *id);//連接設(shè)備的函數(shù)
	void (*disconnect)(struct input_handle *handle);//斷開設(shè)備
	
	struct file_operations *fops;//文件操作函數(shù)集
	int minor;//次設(shè)備號(hào)
	char *name;//設(shè)備名
	
	.....
};
static struct mousedev *mousedev_table[MOUSEDEV_MINORS];
static struct input_handler mousedev_handler = {
	.event =	mousedev_event,//鼠標(biāo)事件回調(diào)函數(shù)
		.connect =	mousedev_connect,//連接device
		.disconnect =	mousedev_disconnect,
		.fops =		&mousedev_fops,//文件操作函數(shù)集
		.minor =	MOUSEDEV_MINOR_BASE,//次設(shè)備號(hào)基數(shù)
		.name =		"mousedev",//設(shè)備名
		.id_table =	mousedev_ids,//本驅(qū)動(dòng)支持的設(shè)備ID
};

他的入口是：
“/input/mousedev . c”
static int __init mousedev_init(void)
{
	input_register_handler(&mousedev_handler);//在虛擬輸入設(shè)備中注冊(cè)鼠標(biāo)輸入驅(qū)動(dòng)器
	
	memset(&mousedev_mix, 0, sizeof(struct mousedev));
	INIT_LIST_HEAD(&mousedev_mix.list);
	init_waitqueue_head(&mousedev_mix.wait);
	mousedev_table[MOUSEDEV_MIX] = &mousedev_mix;//給設(shè)備數(shù)組一個(gè)默認(rèn)的鼠標(biāo)device
	mousedev_mix.exist = 1;
	mousedev_mix.minor = MOUSEDEV_MIX;
	
	devfs_mk_cdev(MKDEV(INPUT_MAJOR, MOUSEDEV_MINOR_BASE + MOUSEDEV_MIX),
		S_IFCHR|S_IRUGO|S_IWUSR, "input/mice");//建立input/mice文件
	class_simple_device_add(input_class, MKDEV(INPUT_MAJOR, MOUSEDEV_MINOR_BASE + MOUSEDEV_MIX),
		NULL, "mice");//在input_class設(shè)備類中增加本設(shè)備驅(qū)動(dòng)程序
	
	
	printk(KERN_INFO "mice: PS/2 mouse device common for all mice\n");
	
	return 0;
}
虛擬鼠標(biāo)設(shè)備驅(qū)動(dòng)器就提供了各種操作的操作集函數(shù)，如read,write,ioctrl,等
static struct file_operations mousedev_fops = {
	.owner =	THIS_MODULE,
		.read =		mousedev_read,
		.write =	mousedev_write,
		.poll =		mousedev_poll,
		.open =		mousedev_open,
		.release =	mousedev_release,
		.fasync =	mousedev_fasync,
};
“/input/input . c”
void input_register_handler(struct input_handler *handler)
{
	struct input_dev *dev;//具體設(shè)備描述結(jié)構(gòu)
	struct input_handle *handle;//設(shè)備句柄
	struct input_device_id *id;//設(shè)備ID
	
	if (!handler) return;
	
	INIT_LIST_HEAD(&handler->h_list);//初始化設(shè)備驅(qū)動(dòng)器的鏈表
	
	if (handler->fops != NULL)
		input_table[handler->minor >> 5] = handler;//把驅(qū)動(dòng)器按次設(shè)備號(hào)放到驅(qū)動(dòng)器數(shù)組里，虛擬設(shè)備支持最多8個(gè)次設(shè)備
	
	list_add_tail(&handler->node, &input_handler_list);//加入驅(qū)動(dòng)器鏈表
	
	list_for_each_entry(dev, &input_dev_list, node)
		if (!handler->blacklist || !input_match_device(handler->blacklist, dev))
			if ((id = input_match_device(handler->id_table, dev)))//用當(dāng)前所有的輸入設(shè)備于驅(qū)動(dòng)器適配
				if ((handle = handler->connect(handler, dev, id)))//適配成功與驅(qū)動(dòng)器連接
					input_link_handle(handle);//連接成功將設(shè)備句柄加到設(shè)備的句柄鏈表中
}
我們先假設(shè)注冊(cè)驅(qū)動(dòng)器時(shí)還沒有一個(gè)輸入設(shè)備在鏈表中，即注冊(cè)時(shí)不需要進(jìn)行驅(qū)動(dòng)器適配。在后面設(shè)備注冊(cè)時(shí)再講適配
連接
這樣就完成了一個(gè)驅(qū)動(dòng)器的注冊(cè)
三，具體設(shè)備。。
這里完成的是真實(shí)與硬件交互的設(shè)備程序。。設(shè)備的描述結(jié)構(gòu)是input_dev
struct input_dev {
	
	void *private;//私有數(shù)據(jù)
	
	char *name;//
	......
	int (*open)(struct input_dev *dev);
	void (*close)(struct input_dev *dev);
	int (*accept)(struct input_dev *dev, struct file *file);
	int (*flush)(struct input_dev *dev, struct file *file);
	int (*event)(struct input_dev *dev, unsigned int type, unsigned int code, int value);
	int (*upload_effect)(struct input_dev *dev, struct ff_effect *effect);
	int (*erase_effect)(struct input_dev *dev, int effect_id);//都是些回調(diào)函數(shù)了
	
	struct input_handle *grab;//設(shè)備句柄
	struct device *dev;//通用設(shè)備結(jié)構(gòu)
	
	struct list_head	h_list;//句柄鏈表input_link_handle函數(shù)將設(shè)備句柄加入到鏈表中。dev響應(yīng)中斷時(shí)如果沒有自己專用的event函數(shù)就遍歷handle列表找到handle指向的input_handler的evnt函數(shù)調(diào)用
	struct list_head	node;
};


struct input_handle {
	
	void *private;//私有數(shù)據(jù) 
	
	int open;
	char *name;
	
	struct input_dev *dev;//設(shè)備
	struct input_handler *handler;//句柄擁有者驅(qū)動(dòng)器
	
	struct list_head	d_node;
	struct list_head	h_node;
};
它的入口是：
“/input/mouse/amimouse . c”
static int __init amimouse_init(void)
{
	if (!MACH_IS_AMIGA || !AMIGAHW_PRESENT(AMI_MOUSE))
		return -ENODEV;
	
	amimouse_dev.evbit[0] = BIT(EV_KEY) | BIT(EV_REL);
	amimouse_dev.relbit[0] = BIT(REL_X) | BIT(REL_Y);
	amimouse_dev.keybit[LONG(BTN_LEFT)] = BIT(BTN_LEFT) | BIT(BTN_MIDDLE) | BIT(BTN_RIGHT);
	amimouse_dev.open = amimouse_open;
	amimouse_dev.close = amimouse_close;
	
	amimouse_dev.name = amimouse_name;
	amimouse_dev.phys = amimouse_phys;
	amimouse_dev.id.bustype = BUS_AMIGA;
	amimouse_dev.id.vendor = 0x0001;
	amimouse_dev.id.product = 0x0002;
	amimouse_dev.id.version = 0x0100;
	
	input_register_device(&amimouse_dev);//注冊(cè)設(shè)備
	
	printk(KERN_INFO "input: %s at joy0dat\n", amimouse_name);
	return 0;
}
“/input/input . c”
void input_register_device(struct input_dev *dev)
{
	struct input_handle *handle;
	struct input_handler *handler;
	struct input_device_id *id;
	
	
	/*
	* If delay and period are pre-set by the driver, then autorepeating
	* is handled by the driver itself and we don't do it in input.c.
	*/
	
	init_timer(&dev->timer);//初始化設(shè)備的定時(shí)器，對(duì)鼠標(biāo)沒什么用mousedev里沒對(duì)他做什么，對(duì)鍵盤有用
	if (!dev->rep[REP_DELAY] && !dev->rep[REP_PERIOD]) {
		dev->timer.data = (long) dev;
		dev->timer.function = input_repeat_key;
		dev->rep[REP_DELAY] = 250;
		dev->rep[REP_PERIOD] = 33;
	}
	
	INIT_LIST_HEAD(&dev->h_list);//初始化設(shè)備的句柄鏈表
	list_add_tail(&dev->node, &input_dev_list);
	
	list_for_each_entry(handler, &input_handler_list, node)//遍歷驅(qū)動(dòng)器列表
		if (!handler->blacklist || !input_match_device(handler->blacklist, dev))  
			if ((id = input_match_device(handler->id_table, dev)))//找到與設(shè)備相配的驅(qū)動(dòng)器，用id_table適配
				if ((handle = handler->connect(handler, dev, id)))//適配成功與驅(qū)動(dòng)器連接// 這里是mouse驅(qū)動(dòng)器
					mousedev的connect函數(shù)是mousedev_connect
					input_link_handle(handle);//把Mousedev返回input_handle(注意不是input_handler)加到dev的handle連表中
				//這樣dev響應(yīng)中斷時(shí)如果沒有自己專用的event函數(shù)就遍歷handle列表找到handle指向的input_handler的evnt函數(shù)調(diào)用
				
#ifdef CONFIG_HOTPLUG
				input_call_hotplug("add", dev);
#endif
				
#ifdef CONFIG_PROC_FS
				input_devices_state++;
				wake_up(&input_devices_poll_wait);
#endif
}

看看驅(qū)動(dòng)器是怎么連接設(shè)備的，他申請(qǐng)一個(gè)mousedev結(jié)構(gòu)用來保存鼠標(biāo)設(shè)備信息。將設(shè)備和設(shè)備句柄及input_handler聯(lián)系起來
放在mousedev_table指針數(shù)組中并給每個(gè)mousedev分配一個(gè)ID minor進(jìn)行唯一標(biāo)志
struct mousedev {
	int exist;//設(shè)備是否存在
	int open;//
	int minor;
	char name[16];
	wait_queue_head_t wait;//等待隊(duì)列
	struct list_head list;//打開mousdev的文件的列表
	struct input_handle handle;//設(shè)備句柄-	
	struct mousedev_hw_data packet;
	unsigned int pkt_count;
	int old_x[4], old_y[4];
	int frac_dx, frac_dy;
	unsigned long touch;
};
struct input_handle {
	
	void *private;
	
	int open;
	char *name;
	
	struct input_dev *dev;
	struct input_handler *handler;
	
	struct list_head	d_node;
	struct list_head	h_node;
};
“/input/mousedev . c”
static struct input_handle *mousedev_connect(struct input_handler *handler, struct input_dev *dev, struct input_device_id *id)
{
	struct mousedev *mousedev;
	int minor = 0;
	
	for (minor = 0; minor < MOUSEDEV_MINORS && mousedev_table[minor]; minor++);
	if (minor == MOUSEDEV_MINORS) {
		printk(KERN_ERR "mousedev: no more free mousedev devices\n");
		return NULL;
	}
	
	if (!(mousedev = kmalloc(sizeof(struct mousedev), GFP_KERNEL)))
		return NULL;
	memset(mousedev, 0, sizeof(struct mousedev));
	
	INIT_LIST_HEAD(&mousedev->list);
	init_waitqueue_head(&mousedev->wait);
	
	mousedev->minor = minor;
	mousedev->exist = 1;
	mousedev->handle.dev = dev;
	mousedev->handle.name = mousedev->name;
	mousedev->handle.handler = handler;
	mousedev->handle.private = mousedev;
	sprintf(mousedev->name, "mouse%d", minor);
	
	if (mousedev_mix.open)
		input_open_device(&mousedev->handle);//看默認(rèn)的mousedev是否需要打開，如果需要就打開設(shè)備。
	
	mousedev_table[minor] = mousedev;
	
	devfs_mk_cdev(MKDEV(INPUT_MAJOR, MOUSEDEV_MINOR_BASE + minor),
		S_IFCHR|S_IRUGO|S_IWUSR, "input/mouse%d", minor);建立設(shè)備文件
	class_simple_device_add(input_class,
		MKDEV(INPUT_MAJOR, MOUSEDEV_MINOR_BASE + minor),
		dev->dev, "mouse%d", minor);
	
	return &mousedev->handle;
}
所有的注冊(cè)已經(jīng)完成
四：設(shè)備控制。。。。
打開設(shè)備。
當(dāng)系統(tǒng)打開一個(gè)設(shè)備時(shí) 如"/dev/input/mouse0"，虛擬文件系統(tǒng)根據(jù)文件節(jié)點(diǎn)INODE中的主設(shè)備

號(hào)在系統(tǒng)字符設(shè)備數(shù)組中搜索主設(shè)備號(hào)相同的字符設(shè)備驅(qū)動(dòng)程序的操作函數(shù)集并將此操作函數(shù)集付給FILE結(jié)構(gòu)的操

作函數(shù)集指針f_ops并執(zhí)行該函數(shù)集中的打開操作。。對(duì)于input類設(shè)備即為input_fops中的input_open_file
“/input/input . c”
static int input_open_file(struct inode *inode, struct file *file)
{
	struct input_handler *handler = input_table[iminor(inode) >> 5];//根據(jù)次設(shè)備號(hào)找到驅(qū)動(dòng)器這里我們就假設(shè)是打開
	鼠標(biāo)既找到了mousedev_handler
	struct file_operations *old_fops, *new_fops = NULL;
	int err;
	
	/* No load-on-demand here? */
	if (!handler || !(new_fops = fops_get(handler->fops)))//得到輸入驅(qū)動(dòng)器的操作函數(shù)集//輸入驅(qū)動(dòng)器。可以是一個(gè)鼠標(biāo)輸入驅(qū)動(dòng)器
		//或者一個(gè)鍵盤輸入驅(qū)動(dòng)器，這里分析的是鼠標(biāo)
		return -ENODEV;
	
		/*
		* That's _really_ odd. Usually NULL ->open means "nothing special",
		* not "no device". Oh, well...
	*/
	if (!new_fops->open) {//如果輸入驅(qū)動(dòng)器沒有打開操作函數(shù)，既設(shè)備文件無法完成打開操作