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Diffstat (limited to 'Documentation/driver-api/usb/usb.rst')
| -rw-r--r-- | Documentation/driver-api/usb/usb.rst | 30 |
1 files changed, 21 insertions, 9 deletions
diff --git a/Documentation/driver-api/usb/usb.rst b/Documentation/driver-api/usb/usb.rst index 078e981e2b16..7f2f41e80c1c 100644 --- a/Documentation/driver-api/usb/usb.rst +++ b/Documentation/driver-api/usb/usb.rst @@ -13,7 +13,7 @@ structure, with the host as the root (the system's master), hubs as interior nodes, and peripherals as leaves (and slaves). Modern PCs support several such trees of USB devices, usually a few USB 3.0 (5 GBit/s) or USB 3.1 (10 GBit/s) and some legacy -USB 2.0 (480 MBit/s) busses just in case. +USB 2.0 (480 MBit/s) buses just in case. That master/slave asymmetry was designed-in for a number of reasons, one being ease of use. It is not physically possible to mistake upstream and @@ -42,7 +42,7 @@ two. One is intended for *general-purpose* drivers (exposed through driver frameworks), and the other is for drivers that are *part of the core*. Such core drivers include the *hub* driver (which manages trees of USB devices) and several different kinds of *host controller -drivers*, which control individual busses. +drivers*, which control individual buses. The device model seen by USB drivers is relatively complex. @@ -109,13 +109,19 @@ well as to make sure they aren't relying on some HCD-specific behavior. USB-Standard Types ================== -In ``<linux/usb/ch9.h>`` you will find the USB data types defined in -chapter 9 of the USB specification. These data types are used throughout +In ``include/uapi/linux/usb/ch9.h`` you will find the USB data types defined +in chapter 9 of the USB specification. These data types are used throughout USB, and in APIs including this host side API, gadget APIs, usb character -devices and debugfs interfaces. +devices and debugfs interfaces. That file is itself included by +``include/linux/usb/ch9.h``, which also contains declarations of a few +utility routines for manipulating these data types; the implementations +are in ``drivers/usb/common/common.c``. -.. kernel-doc:: include/linux/usb/ch9.h - :internal: +.. kernel-doc:: drivers/usb/common/common.c + :export: + +In addition, some functions useful for creating debugging output are +defined in ``drivers/usb/common/debug.c``. .. _usb_header: @@ -155,6 +161,7 @@ rely on 64bit DMA to eliminate another kind of bounce buffer. .. kernel-doc:: drivers/usb/core/urb.c :export: +.. c:namespace:: usb_core .. kernel-doc:: drivers/usb/core/message.c :export: @@ -414,6 +421,12 @@ USBDEVFS_CONNECTINFO know the devnum value already, it's the DDD value of the device file name. +USBDEVFS_GET_SPEED + Returns the speed of the device. The speed is returned as a + numerical value in accordance with enum usb_device_speed + + File modification time is not updated by this request. + USBDEVFS_GETDRIVER Returns the name of the kernel driver bound to a given interface (a string). Parameter is a pointer to this structure, which is @@ -765,8 +778,7 @@ Speed may be: ======= ====================================================== 1.5 Mbit/s for low speed USB 12 Mbit/s for full speed USB - 480 Mbit/s for high speed USB (added for USB 2.0); - also used for Wireless USB, which has no fixed speed + 480 Mbit/s for high speed USB (added for USB 2.0) 5000 Mbit/s for SuperSpeed USB (added for USB 3.0) ======= ====================================================== |