USB_BUS_START_ENUM(9) Host Controller APIs USB_BUS_START_ENUM(9)NAME
usb_bus_start_enum - start immediate enumeration (for OTG)
SYNOPSIS
int usb_bus_start_enum(struct usb_bus * bus, unsigned port_num);
ARGUMENTS
bus
the bus (must use hcd framework)
port_num
1-based number of port; usually bus->otg_port
CONTEXT
in_interrupt
DESCRIPTION
Starts enumeration, with an immediate reset followed later by khubd identifying and possibly configuring the device. This is needed by OTG
controller drivers, where it helps meet HNP protocol timing requirements for starting a port reset.
COPYRIGHT Kernel Hackers Manual 2.6. July 2010 USB_BUS_START_ENUM(9)
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STRUCT USB_GADGET(9) Kernel Mode Gadget API STRUCT USB_GADGET(9)NAME
struct_usb_gadget - represents a usb slave device
SYNOPSIS
struct usb_gadget {
const struct usb_gadget_ops * ops;
struct usb_ep * ep0;
struct list_head ep_list;
enum usb_device_speed speed;
enum usb_device_speed max_speed;
enum usb_device_state state;
unsigned sg_supported:1;
unsigned is_otg:1;
unsigned is_a_peripheral:1;
unsigned b_hnp_enable:1;
unsigned a_hnp_support:1;
unsigned a_alt_hnp_support:1;
const char * name;
struct device dev;
unsigned out_epnum;
unsigned in_epnum;
};
MEMBERS
ops
Function pointers used to access hardware-specific operations.
ep0
Endpoint zero, used when reading or writing responses to driver setup requests
ep_list
List of other endpoints supported by the device.
speed
Speed of current connection to USB host.
max_speed
Maximal speed the UDC can handle. UDC must support this and all slower speeds.
state
the state we are now (attached, suspended, configured, etc)
sg_supported
true if we can handle scatter-gather
is_otg
True if the USB device port uses a Mini-AB jack, so that the gadget driver must provide a USB OTG descriptor.
is_a_peripheral
False unless is_otg, the "A" end of a USB cable is in the Mini-AB jack, and HNP has been used to switch roles so that the "A" device
currently acts as A-Peripheral, not A-Host.
b_hnp_enable
OTG device feature flag, indicating that the A-Host enabled HNP support.
a_hnp_support
OTG device feature flag, indicating that the A-Host supports HNP at this port.
a_alt_hnp_support
OTG device feature flag, indicating that the A-Host only supports HNP on a different root port.
name
Identifies the controller hardware type. Used in diagnostics and sometimes configuration.
dev
Driver model state for this abstract device.
out_epnum
last used out ep number
in_epnum
last used in ep number
DESCRIPTION
Gadgets have a mostly-portable "gadget driver" implementing device functions, handling all usb configurations and interfaces. Gadget
drivers talk to hardware-specific code indirectly, through ops vectors. That insulates the gadget driver from hardware details, and
packages the hardware endpoints through generic i/o queues. The "usb_gadget" and "usb_ep" interfaces provide that insulation from the
hardware.
Except for the driver data, all fields in this structure are read-only to the gadget driver. That driver data is part of the "driver model"
infrastructure in 2.6 (and later) kernels, and for earlier systems is grouped in a similar structure that's not known to the rest of the
kernel.
Values of the three OTG device feature flags are updated before the setup call corresponding to USB_REQ_SET_CONFIGURATION, and before
driver suspend calls. They are valid only when is_otg, and when the device is acting as a B-Peripheral (so is_a_peripheral is false).
AUTHOR
David Brownell <dbrownell@users.sourceforge.net>
Author.
COPYRIGHT Kernel Hackers Manual 3.10 June 2014 STRUCT USB_GADGET(9)