在 Linux 中，USB 驱动程序子系统负责管理 USB 设备与操作系统之间的通信。下面概述了 Linux 中 USB 驱动程序子系统的组件和功能：
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USB 核心： USB 内核是 USB 驱动程序子系统的核心，它为 USB 通信提供了基本的基础设施。它负责设备检测、枚举和管理系统中连接的 USB 设备。
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主机控制器驱动程序： 主机控制器驱动程序负责管理 USB 控制器硬件与系统其他部分之间的硬件接口。这些驱动程序因 USB 控制器的类型而异（例如，不同世代 USB 的 OHCI、UHCI、EHCI、xHCI），通常是 Linux 内核的一部分。
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USB 类驱动程序： Linux 内置支持各种 USB 设备类，如 HID（人机接口设备）、大容量存储、音频和 CDC（通信设备类）。这些类驱动程序允许符合特定标准的 USB 设备开箱即用，无需自定义设备驱动程序。
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USB 设备驱动程序： USB 设备驱动程序是内核模块或内核的一部分，负责管理特定的 USB 设备。每个 USB 设备都需要相应的设备驱动程序才能与设备通信。这些驱动程序处理配置设备、发送和接收数据以及处理设备特定操作等任务。
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USB 小工具驱动程序： 小工具驱动程序能让 Linux 系统充当 USB 外围设备，从而模拟各种 USB 设备功能。小工具驱动程序是 USB 小工具框架的一部分，用于实现大容量存储、以太网、音频、HID（人机接口设备）等功能。
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USB 文件系统（USBFS）： USBFS 是一个虚拟文件系统，可像访问文件一样访问 USB 设备。它允许用户空间应用程序使用标准文件 I/O 操作与 USB 设备交互。USBFS 通常挂载在
/proc/bus/usb/。 -
libusb： libusb 虽然不是内核的一部分，但它是一个用户空间库，为 USB 通信提供了跨平台 API。libusb 广泛用于在 Linux 和其他操作系统上开发 USB 应用程序。
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libusbgx： Libusbgx 是一个用户空间库和框架，用于管理 Linux 上的 USB 小工具。它提供了创建和配置 USB 小工具的 API，使开发人员无需编写低级内核代码就能轻松实现各种 USB 设备功能。
这些组件共同构成了 Linux 中的 USB 驱动程序子系统，为 USB 通信提供了必要的基础架构，并支持各种 USB 设备和功能。
In Linux, the USB driver subsystem manages the communication between USB devices and the operating system. Here’s an overview of the components and functionalities of the USB driver subsystem in Linux:
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USB Core: At the heart of the USB driver subsystem is the USB core, which provides the basic infrastructure for USB communication. It handles device detection, enumeration, and management of USB devices connected to the system.
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Host Controller Drivers: Host controller drivers are responsible for managing the hardware interface between the USB controller hardware and the rest of the system. These drivers vary depending on the type of USB controller (e.g., OHCI, UHCI, EHCI, xHCI for different generations of USB) and are typically part of the Linux kernel.
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USB Class Drivers: Linux includes built-in support for various USB device classes, such as HID (Human Interface Device), Mass Storage, Audio, and CDC (Communication Device Class). These class drivers allow USB devices that adhere to specific standards to work out of the box without requiring custom device drivers.
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USB Device Drivers: USB device drivers are kernel modules or parts of the kernel responsible for managing specific USB devices. Each USB device requires a corresponding device driver to enable communication with the device. These drivers handle tasks such as configuring the device, sending and receiving data, and handling device-specific operations.
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USB Gadget Drivers: Gadget drivers enable a Linux system to act as a USB peripheral device, allowing it to emulate various USB device functionalities. Gadget drivers are part of the USB gadget framework and are used to implement functionalities such as Mass Storage, Ethernet, Audio, HID (Human Interface Device), and more.
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USB Filesystem (USBFS): USBFS is a virtual filesystem that provides access to USB devices as if they were files. It allows user-space applications to interact with USB devices using standard file I/O operations. USBFS is typically mounted at
/proc/bus/usb/. -
libusb: Although not part of the kernel, libusb is a user-space library that provides a cross-platform API for USB communication. It allows applications to interact with USB devices directly without needing to write kernel-level code. libusb is widely used for developing USB applications on Linux and other operating systems.
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libusbgx: Libusbgx is a user-space library and framework for managing USB gadgets on Linux. It provides an API for creating and configuring USB gadgets, allowing developers to easily implement various USB device functionalities without needing to write low-level kernel code.
Together, these components form the USB driver subsystem in Linux, providing the necessary infrastructure for USB communication and enabling support for a wide range of USB devices and functionalities.
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