1/*
2 * This file holds USB constants and structures that are needed for
3 * USB device APIs.  These are used by the USB device model, which is
4 * defined in chapter 9 of the USB 2.0 specification and in the
5 * Wireless USB 1.0 (spread around).  Linux has several APIs in C that
6 * need these:
7 *
8 * - the master/host side Linux-USB kernel driver API;
9 * - the "usbfs" user space API; and
10 * - the Linux "gadget" slave/device/peripheral side driver API.
11 *
12 * USB 2.0 adds an additional "On The Go" (OTG) mode, which lets systems
13 * act either as a USB master/host or as a USB slave/device.  That means
14 * the master and slave side APIs benefit from working well together.
15 *
16 * There's also "Wireless USB", using low power short range radios for
17 * peripheral interconnection but otherwise building on the USB framework.
18 *
19 * Note all descriptors are declared '__attribute__((packed))' so that:
20 *
21 * [a] they never get padded, either internally (USB spec writers
22 *     probably handled that) or externally;
23 *
24 * [b] so that accessing bigger-than-a-bytes fields will never
25 *     generate bus errors on any platform, even when the location of
26 *     its descriptor inside a bundle isn't "naturally aligned", and
27 *
28 * [c] for consistency, removing all doubt even when it appears to
29 *     someone that the two other points are non-issues for that
30 *     particular descriptor type.
31 */
32#ifndef __LINUX_USB_CH9_H
33#define __LINUX_USB_CH9_H
34
35#include <uapi/linux/usb/ch9.h>
36
37
38/**
39 * usb_speed_string() - Returns human readable-name of the speed.
40 * @speed: The speed to return human-readable name for.  If it's not
41 *   any of the speeds defined in usb_device_speed enum, string for
42 *   USB_SPEED_UNKNOWN will be returned.
43 */
44extern const char *usb_speed_string(enum usb_device_speed speed);
45
46
47/**
48 * usb_state_string - Returns human readable name for the state.
49 * @state: The state to return a human-readable name for. If it's not
50 *	any of the states devices in usb_device_state_string enum,
51 *	the string UNKNOWN will be returned.
52 */
53extern const char *usb_state_string(enum usb_device_state state);
54
55#endif /* __LINUX_USB_CH9_H */
56