Linux USB鼠标驱动程序笔记 A

关于这个驱动的源码，我看了几遍，每一次都有不同的感悟，只要自己本来就是菜鸟，慢慢领悟linux中包含的智慧...

本来一开始看的一本书，叫《Linux那些事》，但是太长了，实在看不下去，索性就自己找到这个鼠标的源码，自己研究得了。看完之后对驱动的整个框架有了了解，贴到这里，我在里面可能很多时候提到USB鼠标驱动来说事...（到目前为止，我就看了这个 ） 希望大神指点！

驱动一般分为两部分，一部分跟所在的总线有关，鼠标作为USB总线上的一个device，需要实现usb_device这个结构体，然后挂到USB总线上去；然后另外一部分就是设备本身的功能，可以分为3类：char、block、网络设备（我对网络设备一点不懂，略过），所以需要实现这一类设备的结构体，到了鼠标这里就是input_device了，然后挂载到input core上面；还有一点，每个设备都会有自己的一个结构体，这里就是usb_mouse

struct usb_mouse {
	char name[128];
	char phys[64];
	struct usb_device *usbdev;
	struct input_dev *dev;
	struct urb *irq;

	signed char *data;
	dma_addr_t data_dma;
};

但是这个结构体没有现成的core可以挂，所以linux内核中提供了私有结构体的指针，这里就是input_device和device：

struct input_dev {
	const char *name;
	const char *phys;
	const char *uniq;
	struct input_id id;

	unsigned long evbit[BITS_TO_LONGS(EV_CNT)];
	unsigned long keybit[BITS_TO_LONGS(KEY_CNT)];
	unsigned long relbit[BITS_TO_LONGS(REL_CNT)];
	unsigned long absbit[BITS_TO_LONGS(ABS_CNT)];
	unsigned long mscbit[BITS_TO_LONGS(MSC_CNT)];
	unsigned long ledbit[BITS_TO_LONGS(LED_CNT)];
	unsigned long sndbit[BITS_TO_LONGS(SND_CNT)];
	unsigned long ffbit[BITS_TO_LONGS(FF_CNT)];
	unsigned long swbit[BITS_TO_LONGS(SW_CNT)];

	unsigned int keycodemax;
	unsigned int keycodesize;
	void *keycode;
	int (*setkeycode)(struct input_dev *dev,
			  unsigned int scancode, unsigned int keycode);
	int (*getkeycode)(struct input_dev *dev,
			  unsigned int scancode, unsigned int *keycode);

	struct ff_device *ff;

	unsigned int repeat_key;
	struct timer_list timer;

	int sync;

	int abs[ABS_MAX + 1];
	int rep[REP_MAX + 1];

	unsigned long key[BITS_TO_LONGS(KEY_CNT)];
	unsigned long led[BITS_TO_LONGS(LED_CNT)];
	unsigned long snd[BITS_TO_LONGS(SND_CNT)];
	unsigned long sw[BITS_TO_LONGS(SW_CNT)];

	int absmax[ABS_MAX + 1];
	int absmin[ABS_MAX + 1];
	int absfuzz[ABS_MAX + 1];
	int absflat[ABS_MAX + 1];
	int absres[ABS_MAX + 1];

	int (*open)(struct input_dev *dev);
	void (*close)(struct input_dev *dev);
	int (*flush)(struct input_dev *dev, struct file *file);
	int (*event)(struct input_dev *dev, unsigned int type, unsigned int code, int value);

	struct input_handle *grab;

	spinlock_t event_lock;
	struct mutex mutex;

	unsigned int users;
	bool going_away;

	struct device dev;          //重点在这里！！！

	struct list_head	h_list;
	struct list_head	node;
};

然后就是device的结构体定义

struct device {
	struct device		*parent;

	struct device_private	*p;        //HERE！！此处指向usb_mouse


	struct kobject kobj;
	const char		*init_name; /* initial name of the device */
	struct device_type	*type;

	struct semaphore	sem;	/* semaphore to synchronize calls to
					 * its driver.
					 */

	struct bus_type	*bus;		/* type of bus device is on */
	struct device_driver *driver;	/* which driver has allocated this
					   device */
	void		*platform_data;	/* Platform specific data, device
					   core doesn't touch it */
	struct dev_pm_info	power;

#ifdef CONFIG_NUMA
	int		numa_node;	/* NUMA node this device is close to */
#endif
	u64		*dma_mask;	/* dma mask (if dma'able device) */
	u64		coherent_dma_mask;/* Like dma_mask, but for
					     alloc_coherent mappings as
					     not all hardware supports
					     64 bit addresses for consistent
					     allocations such descriptors. */

	struct device_dma_parameters *dma_parms;

	struct list_head	dma_pools;	/* dma pools (if dma'ble) */

	struct dma_coherent_mem	*dma_mem; /* internal for coherent mem
					     override */
	/* arch specific additions */
	struct dev_archdata	archdata;

	dev_t			devt;	/* dev_t, creates the sysfs "dev" */

	spinlock_t		devres_lock;
	struct list_head	devres_head;

	struct klist_node	knode_class;
	struct class		*class;
	const struct attribute_group **groups;	/* optional groups */

	void	(*release)(struct device *dev);
};

一环扣一环，最后的最后，原来device是幕后老大！！然后就是一系列的probe初始化，初始化这三个结构体自身的属性，以及之间的关联...先写到这里吧，有空再续，最重要的urb还没有完全看懂...