鼠标驱动框架：模拟键盘按键

/* 参考: drivers\hid\usbhid\usbmouse.c */
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/usb.h>
#include <linux/input.h>
#include <linux/hid.h>struct usb_mouse_as_key_desc {struct usb_device *dev;struct usb_interface *intf;const struct usb_device_id *id;int pipe, maxp;int bInterval;void *data_buffer;dma_addr_t data_dma;struct urb *urb;
};/* 1. 构造usb_driver * 1.1 id_table : 能支持哪些设备* 1.2 probe : 记录某些信息, 分配/设置/注册input_dev, 也许也可以在probe里面做"分配/填充/提交URB"*/static struct usb_device_id usb_mouse_as_key_id_table [] = {{ USB_INTERFACE_INFO(USB_INTERFACE_CLASS_HID, USB_INTERFACE_SUBCLASS_BOOT,USB_INTERFACE_PROTOCOL_MOUSE), .driver_info = (kernel_ulong_t)"it is a mouse", },/*.driver_info = (kernel_ulong_t)"it is a mouse" 可以增加一些probe需要的驱动信息，probe里面会自动得到这些信息*/{ }	/* Terminating entry */
};static void usb_mouse_as_key_irq(struct urb *urb)
{struct input_dev *dev = urb->context;struct usb_mouse_as_key_desc *desc = input_get_drvdata(dev);signed char *data = desc->data_buffer;int status;//printk("%s %s %d, urb->status = %d\n", __FILE__, __FUNCTION__, __LINE__, urb->status);switch (urb->status) {case 0:			/* success */break;case -ECONNRESET:	/* unlink */case -ENOENT:case -ESHUTDOWN:return;/* -EPIPE:  should clear the halt */default:		/* error */goto resubmit;  /*如果错误，重新提交*/}//    printk("data[0] = 0x%x\n", data[1]);input_report_key(dev, KEY_L, data[1] & 0x01);   /*查看鼠标数据格式可知data[1]代表 按键状态   见 07_使用libusb读取鼠标数据.md*/input_report_key(dev, KEY_S, data[1] & 0x02);input_report_key(dev, KEY_ENTER, data[1] & 0x04);input_sync(dev);
resubmit:status = usb_submit_urb (urb, GFP_ATOMIC);//printk("%s %s %d, status = %d\n", __FILE__, __FUNCTION__, __LINE__, status);
}static int usb_mouse_as_key_open(struct input_dev *dev)
{struct urb *urb;struct usb_mouse_as_key_desc *desc = input_get_drvdata(dev); /*获取我们之前存入的驱动信息*/int err;urb= desc->urb;printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);err = usb_submit_urb (urb, GFP_KERNEL);printk("%s %s %d, err = %d\n", __FILE__, __FUNCTION__, __LINE__, err);return err;
}static void usb_mouse_as_key_close(struct input_dev *dev)
{struct usb_mouse_as_key_desc *desc = input_get_drvdata(dev);    /*获取我们之前存入的驱动信息*//* 取消/释放 URB */usb_kill_urb(desc->urb);usb_free_urb(desc->urb);
}static int usb_mouse_as_key_probe(struct usb_interface *intf, const struct usb_device_id *id)
{struct usb_device *dev = interface_to_usbdev(intf);struct input_dev *input_dev;struct usb_mouse_as_key_desc *desc;int error;struct usb_host_interface *interface;struct usb_endpoint_descriptor *endpoint;int pipe, maxp;printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);/* 1. 记录设备信息:  intf *//*判断是不是真正的鼠标*/interface = intf->cur_altsetting;if (interface->desc.bNumEndpoints != 1)return -ENODEV;endpoint = &interface->endpoint[0].desc;if (!usb_endpoint_is_int_in(endpoint))  /*如果不是输入端口，说明不是真正的鼠标设备*/return -ENODEV;pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress);maxp = usb_maxpacket(dev, pipe, usb_pipeout(pipe));  /*管道一次性能够传输的数据*/desc = kmalloc(sizeof(struct usb_mouse_as_key_desc), GFP_KERNEL);desc->dev  = dev;desc->intf = intf;desc->id   = id;desc->pipe = pipe;desc->maxp = maxp;desc->bInterval = endpoint->bInterval;desc->data_buffer = usb_alloc_coherent(dev, maxp, GFP_ATOMIC, &desc->data_dma); /*分配dma*///printk("%s %s %d, desc->data_buffer = 0x%x\n", __FILE__, __FUNCTION__, __LINE__, desc->data_buffer);/* 2. 分配/设置/注册input_dev * 2.1 能产生哪类事件* 2.2 能产生这类事件里哪些些事件: L/S/ENTER       ,可见   input   框架* 2.3 设置函数, 比如open* 2.4 在open函数里: 分配/填充/提交 URB* 2.5 URB的回调函数: 解析数据, 上报input_event*/input_dev = devm_input_allocate_device(&intf->dev);  /*里面自带free   ，一般带前缀的allocate，里面都自带free*/input_set_drvdata(input_dev, desc);   /*存入一些我们想要的驱动描述信息*//* set 1: which type event ? */	__set_bit(EV_KEY, input_dev->evbit);/* set 2: which event ? */	__set_bit(KEY_L, input_dev->keybit);__set_bit(KEY_S, input_dev->keybit);__set_bit(KEY_ENTER, input_dev->keybit);/* set 3: open */input_dev->open  = usb_mouse_as_key_open;input_dev->close = usb_mouse_as_key_close;/* 分配/填充 URB */desc->urb = usb_alloc_urb(0, GFP_KERNEL);usb_fill_int_urb(desc->urb,desc->dev,desc->pipe,desc->data_buffer,(desc->maxp > 8 ? 8 : desc->maxp),usb_mouse_as_key_irq,dev,           /*context参数会传入回调函数*/desc->bInterval);/**如果URB使用DMA Buffer，需要如下的设置**/desc->urb->transfer_dma = desc->data_dma;     desc->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;error = input_register_device(input_dev);usb_set_intfdata(intf, input_dev);return 0;
}static void usb_mouse_as_key_disconnect(struct usb_interface *intf)
{struct input_dev *input_dev = usb_get_intfdata (intf);struct usb_mouse_as_key_desc *desc = input_get_drvdata(input_dev);usb_free_coherent(desc->dev, desc->maxp, desc->data_buffer, desc->data_dma);kfree(desc);input_unregister_device(input_dev);usb_set_intfdata(intf, NULL);
}static struct usb_driver usb_mouse_as_key_driver = {.name		= "usbmouse_as_key",.probe		= usb_mouse_as_key_probe,.disconnect	= usb_mouse_as_key_disconnect,.id_table	= usb_mouse_as_key_id_table,
};/* 入口函数  / 出口函数 */
// module_usb_driver(usb_mouse_as_key_driver);可以使用这个宏一键完成入口函数  / 出口函数 等同于196:208行代码
static int __init usb_mouse_as_key__init(void)
{printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);return usb_register(&usb_mouse_as_key_driver);
}static void __exit usb_mouse_as_key__init_exit(void)
{ usb_deregister(&usb_mouse_as_key_driver);
}module_init(usb_mouse_as_key__init);
module_exit(usb_mouse_as_key__init_exit);/* 2. 注册usb_driver */MODULE_LICENSE("GPL");

装载该驱动时，首先要卸载原本内核自带的驱动程序

# 把USB鼠标查到开发板上
# 先看看原来有哪些设备节点
ls /dev/input/event*

# 安装驱动程序
insmod usbmouse_as_key.ko

# 再看看新得到了哪个设备节点
ls /dev/input/event*

# 执行命令, 假设event4是新节点
hexdump /dev/input/event4

# 点击鼠标按键即可观察输出信息

# 第2种测试方法: 执行以下命令，按鼠标左键、右键，再按中键就有输出"ls"
cat /dev/tty0

# 第3种测试方法: 执行以下命令(注意"<"号前后没有空格)，就可以使用鼠标按键在控制台输入字符
exec 0</dev/tty0

打印内核input信息：

hexdump /dev/input/event*  /*具体对应 event几 要自己判断*/