| /* |
| * 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 <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); |
| |
| #endif /* __LINUX_USB_CH9_H */ |