【100ASK_IMX6ULL(带屏) 开发板试用体验】使用libudev库和hidapi驱动USB设备不成功

` 本帖最后由 donatello1996 于 2020-10-31 21:32 编辑

由于开发板自带GPIO接口资源稀少，因此我是打算使用USBHID的方式驱动STM32 单片机进行通信，设想很美好，但是过程并不理想，未能成功实现，以此作为经验教训让大家吸取，进行IMX6UL开发时绕过此坑。这帖先上结果再说过程，同样的USBHID代码我复制到多款Cortex-A嵌入式开发板上，一一测试，现整理列表，供大家参考绕坑：
1.IMX6ULL（韦东山100ask）失败
2.STM32MP157（米尔157）失败
3.三星4418（友善之臂smart4418开发板）失败
4.IMX8开发板（英蓓特IMX8）失败
5.Cubieboard A80 成功
6.三星6818 （友善之臂nanopc t3开发板）成功
7.RK3399开发板成功
8.树莓派3B+ 成功
9.全志H5（Nanopi K1+）成功
10.Windows虚拟机成功

这些测试平台中，使用的hidapi-master代码均是同一份，USB接口引出的方式既有CPU直接引出也有接HUB芯片扩展，且安装的Linux发行版系统镜像不尽相同，有的是Ubuntu，有的是Debian，还有Centos，在编译代码之前都要用apt或者yum安装udev驱动库：

apt install libudev-dev

在与@蚂蚁大佬探究的过程中，他提议我使用

lsu*** -t

指令查看USB接口接入情况，都是一样的，HID设备都能被正确识别出来。STM32单片机的USB协议格式初始化为Custom HID，在没有深究驱动代码的前提下，我得出的结论是不同嵌入式平台对Custom HID的支持存在差异，比如IMX6 IMX8这种NXP平台无法驱动，STM32MP157则是因为别的原因导致无法驱动，那么，现在我开始介绍这个驱动代码的使用方法。

首先要从github或者别的地方下载到hidapi-master源码，这份源码包含api函数实现，测试代码，makefile等：

如图，linux文件夹下面的是针对linux系统的驱动文件，hidapi是全平台通用api头文件，test文件夹下面的是全平台通用的测试代码。

/*******************************************************
HIDAPI - Multi-Platform library for
communication with HID devices.
Alan Ott
Signal 11 Software
8/22/2009
Copyright 2009, All Rights Reserved.
At the discretion of the user of this library,
this software may be licensed under the terms of the
GNU General Public License v3, a BSD-Style license, or the
original HIDAPI license as outlined in the LICENSE.txt,
LICENSE-gpl3.txt, LICENSE-bsd.txt, and LICENSE-orig.txt
files located at the root of the source distribution.
These files may also be found in the public source
code repository located at:
http://github.com/signal11/hidapi .
********************************************************/
/** @file
* @defgroup API hidapi API
*/
#ifndef HIDAPI_H__
#define HIDAPI_H__
#include
#ifdef _WIN32
#define HID_API_EXPORT __declspec(dllexport)
#define HID_API_CALL
#else
#define HID_API_EXPORT /**< API export macro */
#define HID_API_CALL /**< API call macro */
#endif
#define HID_API_EXPORT_CALL HID_API_EXPORT HID_API_CALL /**< API export and call macro*/
#ifdef __cplusplus
extern "C" {
#endif
struct hid_device_;
typedef struct hid_device_ hid_device; /**< opaque hidapi structure */
/** hidapi info structure */
struct hid_device_info {
/** Platform-specific device path */
char *path;
/** Device Vendor ID */
unsigned short vendor_id;
/** Device Product ID */
unsigned short product_id;
/** Serial Number */
wchar_t *serial_number;
/** Device Release Number in binary-coded decimal,
also known as Device Version Number */
unsigned short release_number;
/** Manufacturer String */
wchar_t *manufacturer_string;
/** Product string */
wchar_t *product_string;
/** Usage Page for this Device/Interface
(Windows/Mac only). */
unsigned short usage_page;
/** Usage for this Device/Interface
(Windows/Mac only).*/
unsigned short usage;
/** The USB interface which this logical device
represents. Valid on both Linux implementations
in all cases, and valid on the Windows implementation
only if the device contains more than one interface. */
int interface_number;
/** Pointer to the next device */
struct hid_device_info *next;
};
/** [url=home.php?mod=space&uid=2666770]@Brief[/url] Initialize the HIDAPI library.
This function initializes the HIDAPI library. Calling it is not
strictly necessary, as it will be called automatically by
hid_enumerate() and any of the hid_open_*() functions if it is
needed. This function should be called at the beginning of
execution however, if there is a chance of HIDAPI handles
being opened by different threads simultaneously.
@ingroup API
@returns
This function returns 0 on success and -1 on error.
*/
int HID_API_EXPORT HID_API_CALL hid_init(void);
/** @brief Finalize the HIDAPI library.
This function frees all of the static data associated with
HIDAPI. It should be called at the end of execution to avoid
memory leaks.
@ingroup API
@returns
This function returns 0 on success and -1 on error.
*/
int HID_API_EXPORT HID_API_CALL hid_exit(void);
/** @brief Enumerate the HID Devices.
This function returns a linked list of all the HID devices
attached to the system which match vendor_id and product_id.
If [url=home.php?mod=space&uid=96097]@p[/url] vendor_id is set to 0 then any vendor matches.
If @p product_id is set to 0 then any product matches.
If @p vendor_id and @p product_id are both set to 0, then
all HID devices will be returned.
@ingroup API
[url=home.php?mod=space&uid=3142012]@param[/url] vendor_id The Vendor ID (VID) of the types of device
to open.
@param product_id The Product ID (PID) of the types of
device to open.
@returns
This function returns a pointer to a linked list of type
struct #hid_device, containing information about the HID devices
attached to the system, or NULL in the case of failure. Free
this linked list by calling hid_free_enumeration().
*/
struct hid_device_info HID_API_EXPORT * HID_API_CALL hid_enumerate(unsigned short vendor_id, unsigned short product_id);
/** @brief Free an enumeration Linked List
This function frees a linked list created by hid_enumerate().
@ingroup API
@param devs Pointer to a list of struct_device returned from
hid_enumerate().
*/
void HID_API_EXPORT HID_API_CALL hid_free_enumeration(struct hid_device_info *devs);
/** @brief Open a HID device using a Vendor ID (VID), Product ID
(PID) and optionally a serial number.
If @p serial_number is NULL, the first device with the
specified VID and PID is opened.
@ingroup API
@param vendor_id The Vendor ID (VID) of the device to open.
@param product_id The Product ID (PID) of the device to open.
@param serial_number The Serial Number of the device to open
(Optionally NULL).
@returns
This function returns a pointer to a #hid_device object on
success or NULL on failure.
*/
HID_API_EXPORT hid_device * HID_API_CALL hid_open(unsigned short vendor_id, unsigned short product_id, const wchar_t *serial_number);
/** @brief Open a HID device by its path name.
The path name be determined by calling hid_enumerate(), or a
platform-specific path name can be used (eg: /dev/hidraw0 on
Linux).
@ingroup API
@param path The path name of the device to open
@returns
This function returns a pointer to a #hid_device object on
success or NULL on failure.
*/
HID_API_EXPORT hid_device * HID_API_CALL hid_open_path(const char *path);
/** @brief Write an Output report to a HID device.
The first byte of @p data[] must contain the Report ID. For
devices which only support a single report, this must be set
to 0x0. The remaining bytes contain the report data. Since
the Report ID is mandatory, calls to hid_write() will always
contain one more byte than the report contains. For example,
if a hid report is 16 bytes long, 17 bytes must be passed to
hid_write(), the Report ID (or 0x0, for devices with a
single report), followed by the report data (16 bytes). In
this example, the length passed in would be 17.
hid_write() will send the data on the first OUT endpoint, if
one exists. If it does not, it will send the data through
the Control Endpoint (Endpoint 0).
@ingroup API
@param device A device handle returned from hid_open().
@param data The data to send, including the report number as
the first byte.
@param length The length in bytes of the data to send.
@returns
This function returns the actual number of bytes written and
-1 on error.
*/
int HID_API_EXPORT HID_API_CALL hid_write(hid_device *device, const unsigned char *data, size_t length);
/** @brief Read an Input report from a HID device with timeout.
Input reports are returned
to the host through the INTERRUPT IN endpoint. The first byte will
contain the Report number if the device uses numbered reports.
@ingroup API
@param device A device handle returned from hid_open().
@param data A buffer to put the read data into.
@param length The number of bytes to read. For devices with
multiple reports, make sure to read an extra byte for
the report number.
@param milliseconds timeout in milliseconds or -1 for blocking wait.
@returns
This function returns the actual number of bytes read and
-1 on error. If no packet was available to be read within
the timeout period, this function returns 0.
*/
int HID_API_EXPORT HID_API_CALL hid_read_timeout(hid_device *dev, unsigned char *data, size_t length, int milliseconds);
/** @brief Read an Input report from a HID device.
Input reports are returned
to the host through the INTERRUPT IN endpoint. The first byte will
contain the Report number if the device uses numbered reports.
@ingroup API
@param device A device handle returned from hid_open().
@param data A buffer to put the read data into.
@param length The number of bytes to read. For devices with
multiple reports, make sure to read an extra byte for
the report number.
@returns
This function returns the actual number of bytes read and
-1 on error. If no packet was available to be read and
the handle is in non-blocking mode, this function returns 0.
*/
int HID_API_EXPORT HID_API_CALL hid_read(hid_device *device, unsigned char *data, size_t length);
/** @brief Set the device handle to be non-blocking.
In non-blocking mode calls to hid_read() will return
immediately with a value of 0 if there is no data to be
read. In blocking mode, hid_read() will wait (block) until
there is data to read before returning.
Nonblocking can be turned on and off at any time.
@ingroup API
@param device A device handle returned from hid_open().
@param nonblock enable or not the nonblocking reads
- 1 to enable nonblocking
- 0 to disable nonblocking.
@returns
This function returns 0 on success and -1 on error.
*/
int HID_API_EXPORT HID_API_CALL hid_set_nonblocking(hid_device *device, int nonblock);
/** @brief Send a Feature report to the device.
Feature reports are sent over the Control endpoint as a
Set_Report transfer. The first byte of @p data[] must
contain the Report ID. For devices which only support a
single report, this must be set to 0x0. The remaining bytes
contain the report data. Since the Report ID is mandatory,
calls to hid_send_feature_report() will always contain one
more byte than the report contains. For example, if a hid
report is 16 bytes long, 17 bytes must be passed to
hid_send_feature_report(): the Report ID (or 0x0, for
devices which do not use numbered reports), followed by the
report data (16 bytes). In this example, the length passed
in would be 17.
@ingroup API
@param device A device handle returned from hid_open().
@param data The data to send, including the report number as
the first byte.
@param length The length in bytes of the data to send, including
the report number.
@returns
This function returns the actual number of bytes written and
-1 on error.
*/
int HID_API_EXPORT HID_API_CALL hid_send_feature_report(hid_device *device, const unsigned char *data, size_t length);
/** @brief Get a feature report from a HID device.
Set the first byte of @p data[] to the Report ID of the
report to be read. Make sure to allow space for this
extra byte in @p data[]. Upon return, the first byte will
still contain the Report ID, and the report data will
start in data[1].
@ingroup API
@param device A device handle returned from hid_open().
@param data A buffer to put the read data into, including
the Report ID. Set the first byte of @p data[] to the
Report ID of the report to be read, or set it to zero
if your device does not use numbered reports.
@param length The number of bytes to read, including an
extra byte for the report ID. The buffer can be longer
than the actual report.
@returns
This function returns the number of bytes read plus
one for the report ID (which is still in the first
byte), or -1 on error.
*/
int HID_API_EXPORT HID_API_CALL hid_get_feature_report(hid_device *device, unsigned char *data, size_t length);
/** @brief Close a HID device.
@ingroup API
@param device A device handle returned from hid_open().
*/
void HID_API_EXPORT HID_API_CALL hid_close(hid_device *device);
/** @brief Get The Manufacturer String from a HID device.
@ingroup API
@param device A device handle returned from hid_open().
@param string A wide string buffer to put the data into.
@param maxlen The length of the buffer in multiples of wchar_t.
@returns
This function returns 0 on success and -1 on error.
*/
int HID_API_EXPORT_CALL hid_get_manufacturer_string(hid_device *device, wchar_t *string, size_t maxlen);
/** @brief Get The Product String from a HID device.
@ingroup API
@param device A device handle returned from hid_open().
@param string A wide string buffer to put the data into.
@param maxlen The length of the buffer in multiples of wchar_t.
@returns
This function returns 0 on success and -1 on error.
*/
int HID_API_EXPORT_CALL hid_get_product_string(hid_device *device, wchar_t *string, size_t maxlen);
/** @brief Get The Serial Number String from a HID device.
@ingroup API
@param device A device handle returned from hid_open().
@param string A wide string buffer to put the data into.
@param maxlen The length of the buffer in multiples of wchar_t.
@returns
This function returns 0 on success and -1 on error.
*/
int HID_API_EXPORT_CALL hid_get_serial_number_string(hid_device *device, wchar_t *string, size_t maxlen);
/** @brief Get a string from a HID device, based on its string index.
@ingroup API
@param device A device handle returned from hid_open().
@param string_index The index of the string to get.
@param string A wide string buffer to put the data into.
@param maxlen The length of the buffer in multiples of wchar_t.
@returns
This function returns 0 on success and -1 on error.
*/
int HID_API_EXPORT_CALL hid_get_indexed_string(hid_device *device, int string_index, wchar_t *string, size_t maxlen);
/** @brief Get a string describing the last error which occurred.
@ingroup API
@param device A device handle returned from hid_open().
@returns
This function returns a string containing the last error
which occurred or NULL if none has occurred.
*/
HID_API_EXPORT const wchar_t* HID_API_CALL hid_error(hid_device *device);
#ifdef __cplusplus
}
#endif
#endif