title: usb输入子系统键盘
tags: linux
date: 2018/12/20/ 17:05:08
toc: true
usb输入子系统键盘
设计思路
-
修改匹配的
id_table为键盘static struct usb_device_id myusb_kbd_id_table [] = {
{ USB_INTERFACE_INFO(
USB_INTERFACE_CLASS_HID, //接口类:hid类
USB_INTERFACE_SUBCLASS_BOOT, //子类:启动设备类
USB_INTERFACE_PROTOCOL_KEYBOARD) }, //USB协议:键盘协议
}; -
按键键值的转换，上传的按键数据是8字节的
buf[0]
|--bit0: Left Control是否按下，按下为1
|--bit1: Left Shift 是否按下，按下为1
|--bit2: Left Alt 是否按下，按下为1
|--bit3: Left GUI 是否按下，按下为1
|--bit4: Right Control是否按下，按下为1
|--bit5: Right Shift 是否按下，按下为1
|--bit6: Right Alt 是否按下，按下为1
|--bit7: Right GUI 是否按下，按下为1buf[1]
保留
buf[2~6]
按键值，也就是表示支持最多6个按键一起按，这里的数据需要转换，以按键
A为例//input中上报
#define KEY_A 30 //buf中上传的数据
=04 -
按键上报
这里就会有一个映射表
/drivers/hid/usbhid/usbkbd.c，可以发现usb_kbd_keycode[4]=30也就是实际值，其中0表示保留的意思。static unsigned char usb_kbd_keycode[256] = {
0, 0, 0, 0, 30, 48, 46, 32, 18, 33, 34, 35, 23, 36, 37, 38,
50, 49, 24, 25, 16, 19, 31, 20, 22, 47, 17, 45, 21, 44, 2, 3,
4, 5, 6, 7, 8, 9, 10, 11, 28, 1, 14, 15, 57, 12, 13, 26,
27, 43, 43, 39, 40, 41, 51, 52, 53, 58, 59, 60, 61, 62, 63, 64,
65, 66, 67, 68, 87, 88, 99, 70,119,110,102,104,111,107,109,106,
105,108,103, 69, 98, 55, 74, 78, 96, 79, 80, 81, 75, 76, 77, 71,
72, 73, 82, 83, 86,127,116,117,183,184,185,186,187,188,189,190,
191,192,193,194,134,138,130,132,128,129,131,137,133,135,136,113,
115,114, 0, 0, 0,121, 0, 89, 93,124, 92, 94, 95, 0, 0, 0,
122,123, 90, 91, 85, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
29, 42, 56,125, 97, 54,100,126,164,166,165,163,161,115,114,113,
150,158,159,128,136,177,178,176,142,152,173,140
};如何转换特殊的按键值也就是buf[0]，搜索这个索引表有以下函数
for (i = 0; i < 8; i++)
input_report_key(kbd->dev, usb_kbd_keycode[i + 224], (kbd->new[0] >> i) & 1);也就是对于
kbd->new[0]的每一位上报的是usb_kbd_keycode[i + 224]，查看下226的索引是56#define KEY_LEFTALT 56 -
具体的参考上报
void my_memcpy(unsigned char *dest,unsigned char *src,int len) //复制缓存
{
while(len--)
{
*dest++= *src++;
}
} static void myusb_kbd_irq(struct urb *urb) //键盘中断函数
{
static unsigned char buf1[8]={0,0,0,0,0,0,0,0};
int i; /*上传crtl、shift、atl、windows 等按键*/
for (i = 0; i < 8; i++)
if(((myusb_kbd_buf[0]>>i)&1)!=((buf1[0]>>i)&1))
{
input_report_key(myusb_kbd_dev, usb_kbd_keycode[i + 224], (myusb_kbd_buf[0]>> i) & 1);
input_sync(myusb_kbd_dev); //上传同步事件
} /*上传普通按键*/
for(i=2;i<8;i++)
if(myusb_kbd_buf[i]!=buf1[i])
{
if(myusb_kbd_buf[i] ) //按下事件
input_report_key(myusb_kbd_dev,usb_kbd_keycode[myusb_kbd_buf[i]], 1);
else if(buf1[i]) //松开事件
input_report_key(myusb_kbd_dev,usb_kbd_keycode[buf1[i]], 0);
input_sync(myusb_kbd_dev); //上传同步事件
} my_memcpy(buf1, myusb_kbd_buf, 8); //更新数据
usb_submit_urb(myusb_kbd_urb, GFP_KERNEL);
}
内核的上报代码
static void usb_kbd_irq(struct urb *urb)
{
struct usb_kbd *kbd = urb->context;
int i;
switch (urb->status) { // 只有urb->status==0时,说明数据传输成功
case 0: /* success */
break;
case -ECONNRESET: /* unlink */
case -ENOENT:
case -ESHUTDOWN:
return;
/* -EPIPE: should clear the halt */
default: /* error */
goto resubmit;
}
for (i = 0; i < 8; i++) //上传crtl、shift、atl、windows 等按键
input_report_key(kbd->dev, usb_kbd_keycode[i + 224], (kbd->new[0] >> i) & 1);
for (i = 2; i < 8; i++) { //上传普通按键
/*通过上个状态的按键数据kbd->old[i]的非0值,来查找当前状态的按键数据,若没有找到,说明已经松开了该按键 */
if (kbd->old[i] > 3 && memscan(kbd->new + 2, kbd->old[i], 6) == kbd->new + 8) {
if (usb_kbd_keycode[kbd->old[i]]) //再次判断键盘描述码表的值是否非0
input_report_key(kbd->dev, usb_kbd_keycode[kbd->old[i]], 0); //上传松开事件
else
info("Unknown key (scancode %#x) released.", kbd->old[i]);
}
/*通过当前状态的按键数据kbd->new[i]的非0值,来查找上个状态的按键数据,若没有找到,说明已经按下了该按键 */
if (kbd->new[i] > 3 && memscan(kbd->old + 2, kbd->new[i], 6) == kbd->old + 8) {
if (usb_kbd_keycode[kbd->new[i]]) //再次判断键盘描述码表的值是否非0
input_report_key(kbd->dev, usb_kbd_keycode[kbd->new[i]], 1); //上传按下事件
else
info("Unknown key (scancode %#x) pressed.", kbd->new[i]);
}
}
input_sync(kbd->dev);
memcpy(kbd->old, kbd->new, 8); //更新上个状态值
resubmit:
i = usb_submit_urb (urb, GFP_ATOMIC);
if (i)
err ("can't resubmit intr, %s-%s/input0, status %d",
kbd->usbdev->bus->bus_name,
kbd->usbdev->devpath, i);
}
判断按键中
if (kbd->old[i] > 3因为按键值的索引是从A也就是4开始的-
memscan 是在某个内存中寻找一个自身，这里
memscan(kbd->new + 2, kbd->old[i], 6) == kbd->new + 8)也就是表示找不到的意思，也就是放置类似这种情况第一次扫描 A 按下，在 buf[3]
第二次扫描 A按下，但是在buf[4],但是依然不去上报
void *memscan(void *addr, int c, size_t size)
{
unsigned char *p = addr; while (size) {
if (*p == c)
return (void *)p;
p++;
size--;
}
return (void *)p;
}
完整代码
#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 *myusb_kbd_dev; //input_dev
static unsigned char *myusb_kbd_buf; //虚拟地址缓存区
static dma_addr_t myusb_kbd_phyc; //DMA缓存区;
static __le16 myusb_kbd_size; //数据包长度
static struct urb *myusb_kbd_urb; //urb
static const unsigned char usb_kbd_keycode[252] = {
0, 0, 0, 0, 30, 48, 46, 32, 18, 33, 34, 35, 23, 36, 37, 38,
50, 49, 24, 25, 16, 19, 31, 20, 22, 47, 17, 45, 21, 44, 2, 3,
4, 5, 6, 7, 8, 9, 10, 11, 28, 1, 14, 15, 57, 12, 13, 26,
27, 43, 43, 39, 40, 41, 51, 52, 53, 58, 59, 60, 61, 62, 63, 64,
65, 66, 67, 68, 87, 88, 99, 70,119,110,102,104,111,107,109,106,
105,108,103, 69, 98, 55, 74, 78, 96, 79, 80, 81, 75, 76, 77, 71,
72, 73, 82, 83, 86,127,116,117,183,184,185,186,187,188,189,190,
191,192,193,194,134,138,130,132,128,129,131,137,133,135,136,113,
115,114, 0, 0, 0,121, 0, 89, 93,124, 92, 94, 95, 0, 0, 0,
122,123, 90, 91, 85, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
29, 42, 56,125, 97, 54,100,126,164,166,165,163,161,115,114,113,
150,158,159,128,136,177,178,176,142,152,173,140
}; //键盘码表共有252个数据
void my_memcpy(unsigned char *dest,unsigned char *src,int len) //复制缓存
{
while(len--)
{
*dest++= *src++;
}
}
static void myusb_kbd_irq(struct urb *urb) //键盘中断函数
{
static unsigned char buf1[8]={0,0,0,0,0,0,0,0};
int i;
/*上传crtl、shift、atl、windows 等按键*/
for (i = 0; i < 8; i++)
if(((myusb_kbd_buf[0]>>i)&1)!=((buf1[0]>>i)&1))
{
input_report_key(myusb_kbd_dev, usb_kbd_keycode[i + 224], (myusb_kbd_buf[0]>> i) & 1);
input_sync(myusb_kbd_dev); //上传同步事件
}
/*上传普通按键*/
for(i=2;i<8;i++)
if(myusb_kbd_buf[i]!=buf1[i])
{
if(myusb_kbd_buf[i] ) //按下事件
input_report_key(myusb_kbd_dev,usb_kbd_keycode[myusb_kbd_buf[i]], 1);
else if(buf1[i]) //松开事件
input_report_key(myusb_kbd_dev,usb_kbd_keycode[buf1[i]], 0);
input_sync(myusb_kbd_dev); //上传同步事件
}
my_memcpy(buf1, myusb_kbd_buf, 8); //更新数据
usb_submit_urb(myusb_kbd_urb, GFP_KERNEL);
}
static int myusb_kbd_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
volatile unsigned char i;
struct usb_device *dev = interface_to_usbdev(intf); //设备
struct usb_endpoint_descriptor *endpoint;
struct usb_host_interface *interface; //当前接口
int pipe; //端点管道
interface=intf->cur_altsetting;
endpoint = &interface->endpoint[0].desc; //当前接口下的端点描述符
printk("VID=%x,PID=%x\n",dev->descriptor.idVendor,dev->descriptor.idProduct);
/* 1)分配一个input_dev结构体 */
myusb_kbd_dev=input_allocate_device();
/* 2)设置input_dev支持 按键事件*/
set_bit(EV_KEY, myusb_kbd_dev->evbit);
set_bit(EV_REP, myusb_kbd_dev->evbit); //支持重复按功能
for (i = 0; i < 252; i++)
set_bit(usb_kbd_keycode[i], myusb_kbd_dev->keybit); //添加所有键
clear_bit(0, myusb_kbd_dev->keybit);
/* 3)注册input_dev结构体*/
input_register_device(myusb_kbd_dev);
/* 4)设置USB键盘数据传输 */
/*->4.1)通过usb_rcvintpipe()创建一个端点管道*/
pipe=usb_rcvintpipe(dev,endpoint->bEndpointAddress);
/*->4.2)通过usb_buffer_alloc()申请USB缓冲区*/
myusb_kbd_size=endpoint->wMaxPacketSize;
myusb_kbd_buf=usb_buffer_alloc(dev,myusb_kbd_size,GFP_ATOMIC,&myusb_kbd_phyc);
/*->4.3)通过usb_alloc_urb()和usb_fill_int_urb()申请并初始化urb结构体 */
myusb_kbd_urb=usb_alloc_urb(0,GFP_KERNEL);
usb_fill_int_urb (myusb_kbd_urb, //urb结构体
dev, //usb设备
pipe, //端点管道
myusb_kbd_buf, //缓存区地址
myusb_kbd_size, //数据长度
myusb_kbd_irq, //中断函数
0,
endpoint->bInterval); //中断间隔时间
/*->4.4) 因为我们2440支持DMA,所以要告诉urb结构体,使用DMA缓冲区地址*/
myusb_kbd_urb->transfer_dma =myusb_kbd_phyc; //设置DMA地址
myusb_kbd_urb->transfer_flags =URB_NO_TRANSFER_DMA_MAP; //设置使用DMA地址
/*->4.5)使用usb_submit_urb()提交urb*/
usb_submit_urb(myusb_kbd_urb, GFP_KERNEL);
return 0;
}
static void myusb_kbd_disconnect(struct usb_interface *intf)
{
struct usb_device *dev = interface_to_usbdev(intf); //设备
usb_kill_urb(myusb_kbd_urb);
usb_free_urb(myusb_kbd_urb);
usb_buffer_free(dev, myusb_kbd_size, myusb_kbd_buf,myusb_kbd_phyc);
input_unregister_device(myusb_kbd_dev); //注销内核中的input_dev
input_free_device(myusb_kbd_dev); //释放input_dev
}
static struct usb_device_id myusb_kbd_id_table [] = {
{ USB_INTERFACE_INFO(
USB_INTERFACE_CLASS_HID, //接口类:hid类
USB_INTERFACE_SUBCLASS_BOOT, //子类:启动设备类
USB_INTERFACE_PROTOCOL_KEYBOARD) }, //USB协议:键盘协议
};
static struct usb_driver myusb_kbd_drv = {
.name = "myusb_kbd",
.probe = myusb_kbd_probe,
.disconnect = myusb_kbd_disconnect,
.id_table = myusb_kbd_id_table,
};
/*入口函数*/
static int myusb_kbd_init(void)
{
usb_register(&myusb_kbd_drv);
return 0;
}
/*出口函数*/
static void myusb_kbd_exit(void)
{
usb_deregister(&myusb_kbd_drv);
}
module_init(myusb_kbd_init);
module_exit(myusb_kbd_exit);
MODULE_LICENSE("GPL");