78 Linux libusb库USB HID应用编程笔记

news2024/11/15 8:16:28

1 前言

这几天搞另外一个项目，基于Ubuntu开发一个小的应用程序，就是通过USB HID与设备通信。因此需要在Linux环境编写对应USB HID通信应用。

目前libusb库已经很好的支持USB相关应用的开发，库中提供了丰富的USB接口，用户可以直接调用其提供的API，实现快速开发。

本文对USB HID应用开发进行了简要记录，方便日后自己查看复习。

2 libusb库准备

（1）获取libusb库源码

下面链接是libusb库的源码下载地址。

libusb库源码：https://github.com/libusb/libusb/releases

（2）编译libusb库

获取到源码之后，需要对库进行编译，下面记录了自己编译的指令。

cd libusb-1.0.26/
#配置
./configure --prefix=/home/libusbinstall --build=x86_64-linux --disable-udev
#编译
make
#安装
make install

（3）安装目录

安装之后可以看到目标目录存在两个文件夹：include/ 和 lib/

3 应用示例

下面直接上代码，无需多言，看代码即可（代码风格及规范进行了简化，实际上没那么丑的）。

头文件：hidusb.h

#include <stdint.h>

#include "libusb.h"

int hidUSB_write(libusb_device_handle *dev_handle, unsigned char endpoint, unsigned char *pDataIn, int nDataLen, int ntimeout);
int hidUSB_read(libusb_device_handle *dev_handle,unsigned char endpoint, unsigned char *pDataRcv, int nDataLen, int ntimeout);
int hidUSB_open(libusb_device_handle **dev_hdlout, uint16_t vendor_id, uint16_t product_id);
int hidUSB_close(libusb_device_handle *dev_handle);

void hidUSB_DeInit(void);
int hidUSB_Init(void);

源文件：hidusb.c

#include <stdio.h>
#include <stdint.h>
#include <string.h>

#include "hidusb.h"

static libusb_context 			*gUSBCtx = NULL;

int hidUSB_write(libusb_device_handle *dev_handle, unsigned char endpoint, unsigned char *pDataIn, int nDataLen, int ntimeout)
{
    int ret = -1;
    int transferred = 0;

	
    ret = libusb_interrupt_transfer(dev_handle, endpoint, pDataIn, nDataLen, &transferred, ntimeout);
	if(ret<0){
        perror("failed to write\n");
		return 0;
	}

	return transferred;

}

int hidUSB_read(libusb_device_handle *dev_handle,unsigned char endpoint, unsigned char *pDataRcv, int nDataLen, int ntimeout)
{
    int ret = -1;
    int transferred = 0;
	
    ret = libusb_interrupt_transfer(dev_handle,endpoint, pDataRcv, 64, &transferred, ntimeout);
	if(ret!=0){
        perror("failed to read\n");
		return 0;
	}

	return transferred;

}

int hidUSB_open(libusb_device_handle **dev_hdlout, uint16_t vendor_id, uint16_t product_id)
{
	int ret = -1;
	
	libusb_device_handle *tdev_handle = NULL;

    //打开指定pid和vid的设备
    tdev_handle = libusb_open_device_with_vid_pid(NULL, vendor_id, product_id);
    if(tdev_handle == NULL)
	{
        perror("Cannot open device\n");
		return -1;
    }

	//内核驱动激活与分离（这一句我没怎么搞懂为啥需要，懂的朋友欢迎留言告诉我）
	if(libusb_kernel_driver_active(tdev_handle, 0) == 1)
	{ 
		 printf("Kernel Driver Active\n");
		 if(libusb_detach_kernel_driver(tdev_handle, 0) == 0){
			 printf("Kernel Driver Detached!\n");
		 }
	 }

    ret = libusb_claim_interface(tdev_handle, 0);
    if(ret < 0) {
        perror("Cannot Claim Interface\n");
        goto iExit;
    }


	*dev_hdlout = tdev_handle;

	return 0;

iExit:	
	if(tdev_handle)
		libusb_close(tdev_handle);

	return -1;
}

int hidUSB_close(libusb_device_handle *dev_handle)
{
	int ret = -1;

	if(dev_handle)
	{
		ret = libusb_release_interface(dev_handle, 0);
		if(ret!=0)
		{	
			perror("Cannot libusb_release_interface\n");
			return -1;
		}
		
		libusb_close(dev_handle);
	}

	return 0;
}

void hidUSB_DeInit(void)
{
	libusb_exit(gUSBCtx);
}


int hidUSB_Init(void)
{
    int ret = -1;

	ret = libusb_init(&gUSBCtx); 
	if(ret < 0) 
	{
		perror("libusb_init failed\n");
		return -1;	
	} 

	return 0;
}

主程序：main.c

#include <stdio.h>
#include <unistd.h>
#include "hidusb.h"

//设备的标识号
#define HT232_USB_VID 			0x5548
#define HT232_USB_PID 			0x6666

//这个需要看设备所使用的ep
#define HT232_USB_HID_EPOUT		0x01
#define HT232_USB_HID_EPIN		0x81

int main(void)
{
	int ni = 0;
	int nRet = -1;
	uint8_t ucSndBuf[256] = {0};
	uint8_t ucRcvBuf[256] = {0};
	uint8_t ucSndLen = 0;
	uint8_t ucRcvLen = 0;

	libusb_device_handle *dev_handle = NULL;

	nRet =  hidUSB_Init();
	if(nRet != 0)
	{
		perror("hidUSB_Init failed\r\n");
		return -1;
	}


	nRet = hidUSB_open(&dev_handle, HT232_USB_VID, HT232_USB_PID);
	if(nRet != 0)
	{
		perror("hidUSB_open failed\r\n");
		return -1;
	}



	while(1)
	{
		ucSndBuf[0] = 0x01;
		ucSndBuf[1] = 0x02;
		ucSndBuf[2] = 0x03;
		ucSndBuf[3] = 0x04;
		ucSndLen = 4;
		
		nRet =  hidUSB_write(dev_handle, HT232_USB_HID_EPOUT, ucSndBuf, ucSndLen, 1000);
		if(nRet == 0)
		{
			perror("hidUSB_write failed\r\n");
			goto iSleep;
		}

		ucRcvLen =  hidUSB_read(dev_handle, HT232_USB_HID_EPIN, ucRcvBuf, sizeof(ucRcvBuf), 1000);
		if(ucRcvLen == 0)
		{
			perror("hidUSB_read failed\r\n");
			goto iSleep;
		}

		for(ni=0; ni<ucRcvLen; ni++)
		{
			printf("%02X ", ucRcvBuf[ni]);
		}
		
		printf("\r\n");
iSleep:
		sleep(1);
	}

	nRet = hidUSB_close(dev_handle);
	if(nRet != 0)
	{
		perror("hidUSB_open failed\r\n");
	}


	hidUSB_DeInit();

	return 0;
}

上述即为Linux环境下USB HID应用编程demo。