1STRUCT USB_INTERFACE(9) Host-Side Data Types and Macro STRUCT USB_INTERFACE(9)
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NAME

6       struct_usb_interface - what usb device drivers talk to
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SYNOPSIS

9       struct usb_interface {
10         struct usb_host_interface * altsetting;
11         struct usb_host_interface * cur_altsetting;
12         unsigned num_altsetting;
13         struct usb_interface_assoc_descriptor * intf_assoc;
14         int minor;
15         enum usb_interface_condition condition;
16         unsigned sysfs_files_created:1;
17         unsigned ep_devs_created:1;
18         unsigned unregistering:1;
19         unsigned needs_remote_wakeup:1;
20         unsigned needs_altsetting0:1;
21         unsigned needs_binding:1;
22         unsigned reset_running:1;
23         struct device dev;
24         struct device * usb_dev;
25         atomic_t pm_usage_cnt;
26         struct work_struct reset_ws;
27       };
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MEMBERS

30       altsetting
31           array of interface structures, one for each alternate setting that
32           may be selected. Each one includes a set of endpoint
33           configurations. They will be in no particular order.
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35       cur_altsetting
36           the current altsetting.
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38       num_altsetting
39           number of altsettings defined.
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41       intf_assoc
42           interface association descriptor
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44       minor
45           the minor number assigned to this interface, if this interface is
46           bound to a driver that uses the USB major number. If this interface
47           does not use the USB major, this field should be unused. The driver
48           should set this value in the probe function of the driver, after it
49           has been assigned a minor number from the USB core by calling
50           usb_register_dev.
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52       condition
53           binding state of the interface: not bound, binding (in probe),
54           bound to a driver, or unbinding (in disconnect)
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56       sysfs_files_created
57           sysfs attributes exist
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59       ep_devs_created
60           endpoint child pseudo-devices exist
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62       unregistering
63           flag set when the interface is being unregistered
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65       needs_remote_wakeup
66           flag set when the driver requires remote-wakeup capability during
67           autosuspend.
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69       needs_altsetting0
70           flag set when a set-interface request for altsetting 0 has been
71           deferred.
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73       needs_binding
74           flag set when the driver should be re-probed or unbound following a
75           reset or suspend operation it doesn't support.
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77       reset_running
78           set to 1 if the interface is currently running a queued reset so
79           that usb_cancel_queued_reset doesn't try to remove from the
80           workqueue when running inside the worker thread. See
81           __usb_queue_reset_device.
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83       dev
84           driver model's view of this device
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86       usb_dev
87           if an interface is bound to the USB major, this will point to the
88           sysfs representation for that device.
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90       pm_usage_cnt
91           PM usage counter for this interface
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93       reset_ws
94           Used for scheduling resets from atomic context.
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DESCRIPTION

97       USB device drivers attach to interfaces on a physical device. Each
98       interface encapsulates a single high level function, such as feeding an
99       audio stream to a speaker or reporting a change in a volume control.
100       Many USB devices only have one interface. The protocol used to talk to
101       an interface's endpoints can be defined in a usb “class” specification,
102       or by a product's vendor. The (default) control endpoint is part of
103       every interface, but is never listed among the interface's descriptors.
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105       The driver that is bound to the interface can use standard driver model
106       calls such as dev_get_drvdata on the dev member of this structure.
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108       Each interface may have alternate settings. The initial configuration
109       of a device sets altsetting 0, but the device driver can change that
110       setting using usb_set_interface. Alternate settings are often used to
111       control the use of periodic endpoints, such as by having different
112       endpoints use different amounts of reserved USB bandwidth. All
113       standards-conformant USB devices that use isochronous endpoints will
114       use them in non-default settings.
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116       The USB specification says that alternate setting numbers must run from
117       0 to one less than the total number of alternate settings. But some
118       devices manage to mess this up, and the structures aren't necessarily
119       stored in numerical order anyhow. Use usb_altnum_to_altsetting to look
120       up an alternate setting in the altsetting array based on its number.
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123Kernel Hackers Manual 2.6.       November 2011         STRUCT USB_INTERFACE(9)
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