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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 | 2 | /* |
672027a3 IPG |
3 | * This file holds USB constants and structures that are needed for |
4 | * USB device APIs. These are used by the USB device model, which is | |
5 | * defined in chapter 9 of the USB 2.0 specification and in the | |
6 | * Wireless USB 1.0 (spread around). Linux has several APIs in C that | |
7 | * need these: | |
1da177e4 LT |
8 | * |
9 | * - the master/host side Linux-USB kernel driver API; | |
10 | * - the "usbfs" user space API; and | |
5da0106f | 11 | * - the Linux "gadget" slave/device/peripheral side driver API. |
1da177e4 LT |
12 | * |
13 | * USB 2.0 adds an additional "On The Go" (OTG) mode, which lets systems | |
14 | * act either as a USB master/host or as a USB slave/device. That means | |
5da0106f DB |
15 | * the master and slave side APIs benefit from working well together. |
16 | * | |
17 | * There's also "Wireless USB", using low power short range radios for | |
18 | * peripheral interconnection but otherwise building on the USB framework. | |
672027a3 IPG |
19 | * |
20 | * Note all descriptors are declared '__attribute__((packed))' so that: | |
21 | * | |
22 | * [a] they never get padded, either internally (USB spec writers | |
23 | * probably handled that) or externally; | |
24 | * | |
25 | * [b] so that accessing bigger-than-a-bytes fields will never | |
26 | * generate bus errors on any platform, even when the location of | |
27 | * its descriptor inside a bundle isn't "naturally aligned", and | |
28 | * | |
29 | * [c] for consistency, removing all doubt even when it appears to | |
30 | * someone that the two other points are non-issues for that | |
31 | * particular descriptor type. | |
1da177e4 | 32 | */ |
1da177e4 LT |
33 | #ifndef __LINUX_USB_CH9_H |
34 | #define __LINUX_USB_CH9_H | |
35 | ||
63863b98 | 36 | #include <linux/device.h> |
5e1ddb48 | 37 | #include <uapi/linux/usb/ch9.h> |
1da177e4 | 38 | |
e538dfda MN |
39 | /** |
40 | * usb_speed_string() - Returns human readable-name of the speed. | |
41 | * @speed: The speed to return human-readable name for. If it's not | |
42 | * any of the speeds defined in usb_device_speed enum, string for | |
43 | * USB_SPEED_UNKNOWN will be returned. | |
44 | */ | |
45 | extern const char *usb_speed_string(enum usb_device_speed speed); | |
46 | ||
63863b98 HK |
47 | /** |
48 | * usb_get_maximum_speed - Get maximum requested speed for a given USB | |
49 | * controller. | |
50 | * @dev: Pointer to the given USB controller device | |
51 | * | |
52 | * The function gets the maximum speed string from property "maximum-speed", | |
53 | * and returns the corresponding enum usb_device_speed. | |
54 | */ | |
55 | extern enum usb_device_speed usb_get_maximum_speed(struct device *dev); | |
d1e3d757 FB |
56 | |
57 | /** | |
58 | * usb_state_string - Returns human readable name for the state. | |
59 | * @state: The state to return a human-readable name for. If it's not | |
60 | * any of the states devices in usb_device_state_string enum, | |
61 | * the string UNKNOWN will be returned. | |
62 | */ | |
63 | extern const char *usb_state_string(enum usb_device_state state); | |
64 | ||
dda43a0e | 65 | #endif /* __LINUX_USB_CH9_H */ |