usb - 使用libhid读写USB时

Question

我想使用用户空间库从Linux中的USB HID设备写入和读取响应。搜寻了一段时间，我发现libhid将是解决该问题的方法。

因此，当我使用hid_interrupt_write和hid_interrupt_read发送和接收数据时，发生此错误：

error submitting URB: No such file or directory

但是，当我尝试使用 hid_set_output_report和 hid_get_input_report来读写设备时，发生了此错误：

error sending control message: Connection timed out. 

和

error submitting URB: No such file or directory

而且，我不确定如何获取Usage_Path。

有人可以帮我解决这个问题吗？有什么建议？

这是我的源代码及其执行后的结果：

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


#define EP_HID_IN             0x81
#define EP_HID_OUT            0x02
#define PACKET_INT_LEN            8

char command[8];
char answer[8];

const int PATHLEN = 2;
int const PATH_IN[2] = { 0xffff0001, 0xffff0003 };
int const PATH_OUT[2] = {0xffff0001, 0xffff0005 };

const int SEND_PACKET_LEN = 8;
const int RECV_PACKET_LEN = 8;

bool match_serial_number(struct usb_dev_handle* usbdev, void* custom, unsigned int len)
{
  bool ret;
  char* buffer = (char*)malloc(len);
  usb_get_string_simple(usbdev, usb_device(usbdev)->descriptor.iSerialNumber,
      buffer, len);
  ret = strncmp(buffer, (char*)custom, len) == 0;
  free(buffer);
  return ret;
}

int main(void)
{
  HIDInterface* hid;
  hid_return ret;
  int i = 0;

  HIDInterfaceMatcher matcher = { 0x03eb, 0x4b4e, NULL, NULL, 0 };

  /* see include/debug.h for possible values */
  hid_set_debug(HID_DEBUG_ALL);
  hid_set_debug_stream(stderr);
  /* passed directly to libusb */
  hid_set_usb_debug(1);

  ret = hid_init();
  if (ret != HID_RET_SUCCESS) {
    fprintf(stderr, "hid_init failed with return code %d\n", ret);
    return 1;
  }

  hid = hid_new_HIDInterface();
  if (hid == 0) {
    fprintf(stderr, "hid_new_HIDInterface() failed, out of memory?\n");
    return 1;
  }

  ret = hid_force_open(hid, 0, &matcher, 3);
  if (ret != HID_RET_SUCCESS) {
    fprintf(stderr, "hid_force_open failed with return code %d\n", ret);
    return 1;
  }

  ret = hid_write_identification(stdout, hid);
  if (ret != HID_RET_SUCCESS) {
    fprintf(stderr, "hid_write_identification failed with return code %d\n", ret);
    return 1;
  }

  ret = hid_dump_tree(stdout, hid);
  if (ret != HID_RET_SUCCESS) {
    fprintf(stderr, "hid_dump_tree failed with return code %d\n", ret);
    return 1;
  }

   // Set command,
    command[0] = 0x03;
       command[1] = 0x01;     
       command[2] = 0x31;
       command[3] = 0x31;           
       command[4] = 0x04;
       command[5] = 0x00;
       command[6] = 0x00;
       command[7] = 0x00;
/*

  ret = hid_set_output_report(hid, PATH_IN, PATHLEN, command, SEND_PACKET_LEN);
  if (ret != HID_RET_SUCCESS) {
    fprintf(stderr, "hid_set_output_report failed with return code %d\n", ret);
  }
  ret = hid_get_input_report(hid, PATH_OUT, PATHLEN, answer, RECV_PACKET_LEN);
      if (ret != HID_RET_SUCCESS) {
        fprintf(stderr, "hid_get_input_report failed with return code %d\n", ret);
      }
   */
  ret = hid_interrupt_write(hid, EP_HID_OUT, command, PACKET_INT_LEN, 20);
  if (ret < 0) {
      printf("error in interrupt write\n");
      return 1;
      }
    printf("Reading interrupt\n");
    ret = hid_interrupt_read(hid, EP_HID_IN, answer, PACKET_INT_LEN, 4);
    if(ret < 0) {
     printf("error interrupt read\n");
    return 1;
    }

    printf("Interrupt Transfer Loop Test Result:\n");
    for(i = 0;i < PACKET_INT_LEN; i++) {
        if(i%8 == 0)
        printf("\n");
        printf("%02x; ",command[i]);
    }
    printf("\n");
    printf("\n");
    for(i = 0;i < PACKET_INT_LEN; i++) {
        if(i%8 == 0)
        printf("\n");
        printf("%02x; ",answer[i]);
    }
    printf("\n");
    printf("\n");

  ret = hid_close(hid);
  if (ret != HID_RET_SUCCESS) {
    fprintf(stderr, "hid_close failed with return code %d\n", ret);
    return 1;
  }

  hid_delete_HIDInterface(&hid);

  ret = hid_cleanup();
  if (ret != HID_RET_SUCCESS) {
    fprintf(stderr, "hid_cleanup failed with return code %d\n", ret);
    return 1;
  }

  return 0;
}

结果：

# ./test_libhid
usb_set_debug: Setting debugging level to 1 (on)
 NOTICE: hid_init(): libhid 0.2.15+20060325.0.0 is being initialized.
  TRACE: hid_init(): initialising USB subsystem...
usb_os_init: Found USB VFS at /dev/bus/usb

...
...
device identification of HIDInterface 002/009[0]:
  dev_handle:    0x09a52098
  device:        0x09a55068
  location:      002/009
  manufacturer:  ATMEL
  product:       Firmware Demo
  TRACE: hid_reset_parser(): resetting the HID parser for USB device 002/009[0]...
  TRACE: hid_dump_tree(): iterating the parse tree for USB device 002/009[0]...
parse tree of HIDInterface 002/009[0]:
  path: 0xffff0001.0xffff0002; type: 0x80
  path: 0xffff0001.0xffff0003; type: 0x80
  path: 0xffff0001.0x00000000; type: 0x80
  path: 0xffff0001.0x00000000; type: 0x80
  path: 0xffff0001.0x00000000; type: 0x80
  path: 0xffff0001.0x00000000; type: 0x80
  path: 0xffff0001.0x00000000; type: 0x80
  path: 0xffff0001.0x00000000; type: 0x80
  path: 0xffff0001.0xffff0004; type: 0x90
  path: 0xffff0001.0xffff0005; type: 0x90
  path: 0xffff0001.0x00000000; type: 0x90
  path: 0xffff0001.0x00000000; type: 0x90
  path: 0xffff0001.0x00000000; type: 0x90
  path: 0xffff0001.0x00000000; type: 0x90
  path: 0xffff0001.0x00000000; type: 0x90
  path: 0xffff0001.0x00000000; type: 0x90
  path: 0xffff0001.0xffff0006; type: 0xb0
  path: 0xffff0001.0xffff0007; type: 0xb0
  path: 0xffff0001.0x00000000; type: 0xb0
  path: 0xffff0001.0x00000000; type: 0xb0
  TRACE: hid_reset_parser(): resetting the HID parser for USB device 002/009[0]...
  TRACE: hid_set_output_report(): looking up report ID...
  TRACE: hid_prepare_parse_path(): preparing search path of depth 2 for parse tree of USB device 002/009[0]...
  TRACE: hid_prepare_parse_path(): search path prepared for parse tree of USB device 002/009[0].
 NOTICE: hid_find_object(): found requested item.
  TRACE: hid_set_output_report(): sending report ID 0x00 (length: 8) to USB device 002/009[0]...
WARNING: hid_set_output_report(): failed to send report to USB device 002/009[0]:error sending control message: Connection timed out.
hid_set_output_report failed with return code 19
Reading interrupt
  TRACE: hid_interrupt_read(): retrieving interrupt report from device 002/009[0] ...
WARNING: hid_interrupt_read(): failed to get interrupt read from device 002/009[0]: error submitting URB: No such file or directory
Interrupt Transfer Loop Test Result:

03; 01; 31; 31; 04; 00; 00; 00;


00; 00; 00; 00; 00; 00; 00; 00;

  TRACE: hid_close(): closing USB device 002/009[0]...
  TRACE: hid_close(): closing handle of USB device 002/009[0]...
 NOTICE: hid_close(): successfully closed USB device 002/009[0].
  TRACE: hid_reset_parser(): resetting the HID parser for USB device 002/009[0]...
  TRACE: hid_close(): freeing memory allocated for HID parser...
  TRACE: hid_close(): resetting HIDInterface...
 NOTICE: hid_cleanup(): successfully deinitialised HID library.

Answer 1

Libhid建立在libusb之上。老实说，libusb是一个更好的库。它使得来回通信非常容易。实际上，如果您有兴趣，我可以向您发送一个示例程序，该程序可以读写HID设备。

Libhid需要付出更多的努力，而文档则要差得多。

当然，无论哪种方式，您都必须确保要写入正确的设备（通过检查产品和供应商ID），并且如果使用libhid，还必须将正确的数据包发送到正确的路径。 （共有三种路径：输入，输出和功能）。

我确实建议使用libusb。