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/* SPDX-License-Identifier: GPL-2.0 */
/*
* This file holds USB constants and structures that are needed for
* USB device APIs. These are used by the USB device model, which is
* defined in chapter 9 of the USB 2.0 specification and in the
* Wireless USB 1.0 (spread around). Linux has several APIs in C that
* need these:
*
* - the master/host side Linux-USB kernel driver API;
* - the "usbfs" user space API; and
* - the Linux "gadget" slave/device/peripheral side driver API.
*
* USB 2.0 adds an additional "On The Go" (OTG) mode, which lets systems
* act either as a USB master/host or as a USB slave/device. That means
* the master and slave side APIs benefit from working well together.
*
* There's also "Wireless USB", using low power short range radios for
* peripheral interconnection but otherwise building on the USB framework.
*
* Note all descriptors are declared '__attribute__((packed))' so that:
*
* [a] they never get padded, either internally (USB spec writers
* probably handled that) or externally;
*
* [b] so that accessing bigger-than-a-bytes fields will never
* generate bus errors on any platform, even when the location of
* its descriptor inside a bundle isn't "naturally aligned", and
*
* [c] for consistency, removing all doubt even when it appears to
* someone that the two other points are non-issues for that
* particular descriptor type.
*/
#ifndef __LINUX_USB_CH9_H
#define __LINUX_USB_CH9_H
#include <linux/device.h>
#include <uapi/linux/usb/ch9.h>
/**
* usb_speed_string() - Returns human readable-name of the speed.
* @speed: The speed to return human-readable name for. If it's not
* any of the speeds defined in usb_device_speed enum, string for
* USB_SPEED_UNKNOWN will be returned.
*/
extern const char *usb_speed_string(enum usb_device_speed speed);
/**
* usb_get_maximum_speed - Get maximum requested speed for a given USB
* controller.
* @dev: Pointer to the given USB controller device
*
* The function gets the maximum speed string from property "maximum-speed",
* and returns the corresponding enum usb_device_speed.
*/
extern enum usb_device_speed usb_get_maximum_speed(struct device *dev);
/**
* usb_state_string - Returns human readable name for the state.
* @state: The state to return a human-readable name for. If it's not
* any of the states devices in usb_device_state_string enum,
* the string UNKNOWN will be returned.
*/
extern const char *usb_state_string(enum usb_device_state state);
#endif /* __LINUX_USB_CH9_H */
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