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如何在连接的 USB 设备上加载我的自定义驱动程序模块？

tag-icon • tag-icon linux-kernel drivers kernel-modules usb-device
如何在连接的 USB 设备上加载我的自定义驱动程序模块？

我正在为 LED 徽章编写一个小型简单的驱动器模块。我遵循了一些教程和参考资料来完成这项工作。所有这些似乎都暗示当设备插入时会自动加载该模块。但是，当我运行usb-devices相应的设备时有 driver Driver=usbfs。

我有另一个终端正在执行后续操作dmesg，它根本不会吐出任何调试消息。当我尝试连接和断开连接时，会出现以下内容：

[36078.726962] usb 1-2: USB disconnect, device number 24
[36080.925619] usb 1-2: new full-speed USB device number 25 using xhci_hcd
[36081.067062] usb 1-2: New USB device found, idVendor=0483, idProduct=5750
[36081.067067] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[36081.067071] usb 1-2: Product: CHW20160112 HID
[36081.067075] usb 1-2: Manufacturer: Chuanghongweitech1
[36081.068695] input: Chuanghongweitech1 CHW20160112 HID as /devices/pci0000:00/0000:00:14.0/usb1/1-2/1-2:1.0/0003:0483:5750.0018/input/input40
[36081.069072] hid-generic 0003:0483:5750.0018: input,hidraw2: USB HID v1.10 Device [Chuanghongweitech1 CHW20160112 HID] on usb-0000:00:14.0-2/input0

如果我向日志发出带有此输出的sudo insmod ledbadge_drv.ko（用于卸载） ，我的模块就会卸载/加载：rmmod

[36216.554620] ledbadge:, Unloading module. Handler: ledbadge_exit
[36216.554620] ledbadge:, Attempting to deregister USB device.
[36216.554621] usbcore: deregistering interface driver ledbadge
[36216.554647] ledbadge:, Leaving module!
[36217.632615] ledbadge:, Loading module. Handler: ledbadge_init
[36217.632616] ledbadge:, Attempting to register USB device.
[36217.632636] usbcore: registered new interface driver ledbadge

该模块的代码如下：

#include <linux/init.h>
#include <linux/module.h>
#include <linux/usb.h> 



#define LEDBADGE_VENDOR_ID  0x0483
#define LEDBADGE_PRODUCT_ID 0x5750
#define LEDBADGE_MOD_NAME   "ledbadge"
#define LEDBADGE_DRV_NAME   "ledbadge"


/************* usb operations *************/

/* 
    ledbadge_probe

        called when plugging the USB device */


static int ledbadge_probe(struct usb_interface *interface, const struct usb_device_id *id)
{   
    printk(KERN_NOTICE "Led Badge driver (%04X: %04X) plugged \n", id->idVendor, id->idProduct);
    return 0;
}


/* 
    ledbadge_disconnect

        called when unplugging the USB device */

static void ledbadge_disconnect(struct usb_interface *interface) 
{
    printk(KERN_NOTICE "%s:, ledbage USB device removed", LEDBADGE_DRV_NAME);
}




/************* usb driver *************/

// information required to recognize the device

static struct usb_device_id ledbadge_table [] = {
    {USB_DEVICE(LEDBADGE_VENDOR_ID, LEDBADGE_PRODUCT_ID)},
    { }, // terminating entry
};
MODULE_DEVICE_TABLE(usb, ledbadge_table);


static struct usb_driver ledbadge_driver = {
    .name = LEDBADGE_DRV_NAME,
    .id_table = ledbadge_table,
    .probe = ledbadge_probe,
    .disconnect = ledbadge_disconnect,
};








/************** module definition **************/

/* ledbadge_init

        caled on module loading */

static int __init ledbadge_init(void) 
{
    int ret = -1; 

    printk(KERN_NOTICE "%s:, Loading module. Handler: %s",
             LEDBADGE_MOD_NAME, __FUNCTION__); 

    printk(KERN_NOTICE "%s:, Attempting to register USB device.", LEDBADGE_MOD_NAME); 

    // attempt to register usb device
    ret = usb_register(&ledbadge_driver);

    // log dmesg of status
    if(ret == 0) printk(KERN_NOTICE "%s:, Device registered!", LEDBADGE_MOD_NAME);
    else         printk(KERN_ERR    "%s:, Device registration failed > %d", LEDBADGE_MOD_NAME, ret);

    return ret; 
}

/* ledbadge_exit

        caled on module unloading */

static void __exit ledbadge_exit(void) 
{
    printk(KERN_NOTICE "%s:, Unloading module. Handler: %s",
             LEDBADGE_MOD_NAME, __FUNCTION__); 

    printk(KERN_NOTICE "%s:, Attempting to deregister USB device.", LEDBADGE_MOD_NAME); 

    // attempt to deregister usb device
    usb_deregister(&ledbadge_driver);

    // log dmesg of status
    printk(KERN_NOTICE "%s:, Leaving module!", LEDBADGE_MOD_NAME);
}

module_init(ledbadge_init);
module_exit(ledbadge_exit); 

MODULE_LICENSE("GPL");

答案1

您是否将模块放入/lib/modules/<your kernel version>目录树中并depmod在之后运行？

如果是这样，那么/lib/modules/<your kernel version>/modules.alias文件中应该有这样一行：

alias usb:v0483p5750d*dc*dsc*dp*ic*isc*ip*in* ledbadge

当内核看到一个新的 USB 设备时，它会读取其供应商和产品 ID 以及许多其他属性，并将这些属性用作系统创建的模块别名的组件，如上所示。然后内核会使用modprobe该别名执行命令（实际机制在 Linux 2.6 及更高版本的历史中有所不同）。如果modprobe找到与其匹配的别名定义，则加载该别名定义中列出的模块。

我认为匹配的方式是最具体的匹配获胜。目前看来该hid-generic模块可能会胜过您的模块（假设您depmod在安装模块后已运行），因此您的 ledbadge 设备可能是 USB HID 类设备。因此，您可能还需要/替代地声明 USB HID 设备别名。像这样的东西：

static const struct hid_device_id ledbadge_hid_table[] = {
        {HID_USB_DEVICE(LEDBADGE_VENDOR_ID,LEDBADGE_PRODUCT_ID)},
        { } // terminating entry
};

MODULE_DEVICE_TABLE(hid, ledbadge_hid_table);

文件中的结果行modules.alias应类似于：

alias hid:b0003g*v00000483p00005750 ledbadge

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