嵌入式linux驱动-usb实现按键功能笔记

一、开发环境

1、内核：Linux 2.6.22.6；

2、JZ2440v3

3、ubuntu 9.10
二、过程

三、程序

#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 *usb_key_dev;
static char *usb_buff;
static dma_addr_t usb_buff_phys;
static int len;
static struct urb *usb_key_urb;

static void usbmouse_as_key_irq(struct urb *urb)
{
int i;
static int cnt;
static unsigned char pre_val;

/*

printk("data cnt = %d ",++cnt);
for(i=0;i<len;i++)
{
printk("%02x ",usb_buff[i]);
}
printk("\n");

*/

//usb_buff[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_buff[0] & (1<<0)))
{
/* 左键发生了变化 */
input_event(usb_key_dev, EV_KEY, KEY_L, (usb_buff[0] & (1<<0)) ? 1 : 0);
input_sync(usb_key_dev);
}

if ((pre_val & (1<<1)) != (usb_buff[0] & (1<<1)))
{
/* 右键发生了变化 */
input_event(usb_key_dev, EV_KEY, KEY_S, (usb_buff[0] & (1<<1)) ? 1 : 0);
input_sync(usb_key_dev);
}

if ((pre_val & (1<<2)) != (usb_buff[0] & (1<<2)))
{
/* 中键发生了变化 */
input_event(usb_key_dev, EV_KEY, KEY_ENTER, (usb_buff[0] & (1<<2)) ? 1 : 0);
input_sync(usb_key_dev);
}

pre_val = usb_buff[0];

//重新提交urb
usb_submit_urb(usb_key_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;

/*printk("fount usb mouse \n");
printk("bcdUSB = %x \n",dev->descriptor.bcdUSB);
printk("VID = %x \n",dev->descriptor.idVendor);
printk("PID = %x \n",dev->descriptor.idProduct);*/

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

//1.分配一个input_dev 结构体
usb_key_dev=input_allocate_device();

//2.设置
//2.1能长生那类事件
set_bit(EV_KEY,usb_key_dev->evbit);
set_bit(EV_REP,usb_key_dev->evbit);

//2.2 能产生这类事件的那些事件
set_bit(KEY_L,usb_key_dev->keybit);
set_bit(KEY_S,usb_key_dev->keybit);
set_bit(KEY_ENTER,usb_key_dev->keybit);

//3.注册
input_register_device(usb_key_dev);
//4.硬件相关的操作
//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_buff = usb_buffer_alloc(dev, 8, GFP_ATOMIC, &usb_buff_phys);
//使用3要素
//分配usb request block
usb_key_urb=usb_alloc_urb(0, GFP_KERNEL);
//使用3要素设置urb
usb_fill_int_urb(usb_key_urb, dev, pipe, usb_buff,len,usbmouse_as_key_irq,NULL , endpoint->bInterval);
usb_key_urb->transfer_dma = usb_buff_phys;
usb_key_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
//使用urb
usb_submit_urb(usb_key_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 usb mouse \n");
usb_kill_urb(usb_key_urb);
usb_free_urb(usb_key_urb);
usb_buffer_free(dev, len,usb_buff,usb_buff_phys);
input_unregister_device(usb_key_dev);
input_free_device(usb_key_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 */
};

//1.分配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_driver
usb_register(&usbmouse_as_key_driver);

return 0;
}

static void usbmouse_as_key_exit(void)
{
//卸载usb_driver
usb_deregister(&usbmouse_as_key_driver);
}

module_init(usbmouse_as_key_init);
module_exit(usbmouse_as_key_exit);

MODULE_LICENSE("GPL");