usb设备驱动程序

韦老师写的，供参考

/*
 * drivers\hid\usbhid\usbmouse.c
 */


#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/usb/input.h>
#include <linux/hid.h>


static struct input_dev *uk_dev;
static char *usb_buf;
static dma_addr_t usb_buf_phys;
static int len;
static struct urb *uk_urb;


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) },
//{USB_DEVICE(0x1234,0x5678)},
{ } /* 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
/* USB鼠标数据含义
* data[0]: bit0-左键, 1-按下, 0-松开
*          bit1-右键, 1-按下, 0-松开
*          bit2-中键, 1-按下, 0-松开 
*
     */
if ((pre_val & (1<<0)) != (usb_buf[0] & (1<<0)))
{
/* 左键发生了变化 */
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)))
{
/* 右键发生了变化 */
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)))
{
/* 中键发生了变化 */
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urb */
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;
int pipe;

interface = intf->cur_altsetting;
endpoint = &interface->endpoint[0].desc;


/* a. 分配一个input_dev */
uk_dev = input_allocate_device();

/* b. 设置 */
/* b.1 能产生哪类事件 */
set_bit(EV_KEY, uk_dev->evbit);
set_bit(EV_REP, uk_dev->evbit);

/* b.2 能产生哪些事件 */
set_bit(KEY_L, uk_dev->keybit);
set_bit(KEY_S, uk_dev->keybit);
set_bit(KEY_ENTER, uk_dev->keybit);

/* c. 注册 */
input_register_device(uk_dev);

/* d. 硬件相关操作 */
/* 数据传输3要素: 源,目的,长度 */
/* 源: USB设备的某个端点 */
pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress);


/* 长度: */
len = endpoint->wMaxPacketSize;


/* 目的: */
usb_buf = usb_buffer_alloc(dev, len, GFP_ATOMIC, &usb_buf_phys);


/* 使用"3要素" */
/* 分配usb request block */
uk_urb = usb_alloc_urb(0, GFP_KERNEL);
/* 使用"3要素设置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);


//printk("disconnect usbmouse!\n");
usb_kill_urb(uk_urb);
usb_free_urb(uk_urb);


usb_buffer_free(dev, len, usb_buf, usb_buf_phys);
input_unregister_device(uk_dev);
input_free_device(uk_dev);
}


/* 1. 分配/设置usb_driver */
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_as_key_init(void)
{
/* 2. 注册 */
usb_register(&usbmouse_as_key_driver);
return 0;
}


static void usbmouse_as_key_exit(void)
{
usb_deregister(&usbmouse_as_key_driver);
}


module_init(usbmouse_as_key_init);
module_exit(usbmouse_as_key_exit);


MODULE_LICENSE("GPL");