LINUX USB驅動（4）-鼠標驅動實例

1怎麼寫USB設備驅動程序？

1.1分配/設置USB_driver結構體
.id_table
.probe
.disconnect
1.2.註冊

2.實例代碼

*
參考：\itop4412_kernel_3.0\drivers\hid\usbhid\Usbmouse.c
*/

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/usb/input.h>
#include <linux/hid.h>
static int len;
static char *usb_buf;
static struct urb *uk_urb; 
static dma_addr_t usb_buf_phys;
struct input_dev *uk_dev;
static struct usb_device_id usbmouse_as_key_id_table [] = {
    { USB_INTERFACE_INFO(USB_INTERFACE_CLASS_HID, USB_INTERFACE_SUBCLASS_BOOT,
        USB_INTERFACE_PROTOCOL_MOUSE) },
    { } /* Terminating entry */
};
static void usbmouse_as_key_irq(struct urb *urb)
{
    static unsigned char pre_val;
#if 0
    int i;
    static int cnt = 0;
    printk("data cnt %d: ",++cnt);
    for(i=0;i<len;i++)
    {
        printk("%02x",usb_buf[i]);  
    }
    printk("\n");
#endif
/*
data[0]:bit0-左鍵，1-按下，0-鬆開
        bit1-中鍵，1-按下，0-鬆開
        bit2-右鍵，1-按下，0-鬆開
*/

if((pre_val&(1<<0))!=(usb_buf[0]&(1<<0)))
{
    /*左鍵發生變化*/
    input_event(uk_dev,EV_KEY,KEY_L,(usb_buf[0]&(1<<0))?1:0);
    input_sync(uk_dev);
}
if((pre_val&(1<<1))!=(usb_buf[0]&(1<<1)))
{
    /*右發生變化*/
    input_event(uk_dev,EV_KEY,KEY_S,(usb_buf[0]&(1<<1))?1:0);
    input_sync(uk_dev);
}
if((pre_val&(1<<2))!=(usb_buf[0]&(1<<2)))
{
    /*中鍵發生變化*/
    input_event(uk_dev,EV_KEY,KEY_ENTER,(usb_buf[0]&(1<<2))?1:0);
    input_sync(uk_dev);
}
    pre_val=usb_buf[0];

    //重新提交
    usb_submit_urb(uk_urb,GFP_KERNEL);
}

static int usbmouse_as_key_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
    struct usb_device *dev = interface_to_usbdev(intf);
    struct usb_host_interface *interface;
    struct usb_endpoint_descriptor *endpoint;
    interface = intf->cur_altsetting;
    int pipe;
    //a.分配一個input_dev
    uk_dev = input_allocate_device();
    //b.設置
    //b.1能產生哪類事件
    set_bit(EV_KEY,uk_dev->evbit);
    set_bit(EV_REP,uk_dev->evbit);
    //b.2能產生哪些事件
    set_bit(KEY_L,uk_dev->keybit);
    set_bit(KEY_S,uk_dev->keybit);
    set_bit(KEY_ENTER,uk_dev->keybit);
    //c.註冊
    input_register_device(uk_dev);
    //d.硬件相關操作
    /*數據傳輸3要素*/
    //源:USB設備的某個端點
    endpoint = &interface->endpoint[0].desc;
    pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress);
    //長度
    len=endpoint->wMaxPacketSize;
    //目的
    usb_buf=usb_alloc_coherent(dev,len,GFP_ATOMIC,&usb_buf_phys);
    /*使用三要素*/
    //分配USB請求塊
    uk_urb=usb_alloc_urb(0,GFP_KERNEL);
    /*使用3要素設置urb*/
    usb_fill_int_urb(uk_urb, dev, pipe, usb_buf,len,usbmouse_as_key_irq, NULL, endpoint->bInterval);
    uk_urb->transfer_dma = usb_buf_phys;
    uk_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
    /*使用URB*/
    usb_submit_urb(uk_urb,GFP_KERNEL);

    return 0;
}
static void usbmouse_as_key_disconnect(struct usb_interface *intf)
{
    struct usb_device *dev = interface_to_usbdev(intf);
    usb_kill_urb(uk_urb);
    usb_free_urb(uk_urb);
    usb_free_coherent(dev,len,usb_buf,usb_buf_phys);
    input_unregister_device(uk_dev);
    input_free_device(uk_dev);


}

//分配、設置usb_driver結構體
static struct usb_driver usbmouse_as_key_driver = {
    .name       = "usbmouse_as_key",
    .probe      = usbmouse_as_key_probe,
    .disconnect = usbmouse_as_key_disconnect,
    .id_table   = usbmouse_as_key_id_table,
};
static int usbmouse_init()
{
    /*註冊*/
    usb_register(&usbmouse_as_key_driver);
    return 0;
}
static void usbmouse_exit()
{

usb_deregister(&usbmouse_as_key_driver);

}
module_init(usbmouse_init);
module_exit(usbmouse_exit);
MODULE_LICENSE("GPL");

3.測試

2.1make menuconfig去掉原來的USB鼠標驅動
-> Device Drivers │
-> HID Devices (HID_SUPPORT [=y]) │
<>USB Human interface Device (full HID) support
2.2make zImage並使用新內核啓動
2.3insmod usbmouse_as_key.ko
2.4在開發板上接入、拔出USB鼠標
2.2測試3：
2.2.1 insmod usbmouse_as_key.ko
2.2.2接上鼠標
2.2.3查看鼠標數據