1STRUCT USB_GADGET(9)        Kernel Mode Gadget API        STRUCT USB_GADGET(9)
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NAME

6       struct_usb_gadget - represents a usb slave device
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SYNOPSIS

9       struct usb_gadget {
10         const struct usb_gadget_ops * ops;
11         struct usb_ep * ep0;
12         struct list_head ep_list;
13         enum usb_device_speed speed;
14         unsigned is_dualspeed:1;
15         unsigned is_otg:1;
16         unsigned is_a_peripheral:1;
17         unsigned b_hnp_enable:1;
18         unsigned a_hnp_support:1;
19         unsigned a_alt_hnp_support:1;
20         const char * name;
21         struct device dev;
22       };
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MEMBERS

25       ops
26           Function pointers used to access hardware-specific operations.
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28       ep0
29           Endpoint zero, used when reading or writing responses to driver
30           setup requests
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32       ep_list
33           List of other endpoints supported by the device.
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35       speed
36           Speed of current connection to USB host.
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38       is_dualspeed
39           True if the controller supports both high and full speed operation.
40           If it does, the gadget driver must also support both.
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42       is_otg
43           True if the USB device port uses a Mini-AB jack, so that the gadget
44           driver must provide a USB OTG descriptor.
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46       is_a_peripheral
47           False unless is_otg, the “A” end of a USB cable is in the Mini-AB
48           jack, and HNP has been used to switch roles so that the “A” device
49           currently acts as A-Peripheral, not A-Host.
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51       b_hnp_enable
52           OTG device feature flag, indicating that the A-Host enabled HNP
53           support.
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55       a_hnp_support
56           OTG device feature flag, indicating that the A-Host supports HNP at
57           this port.
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59       a_alt_hnp_support
60           OTG device feature flag, indicating that the A-Host only supports
61           HNP on a different root port.
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63       name
64           Identifies the controller hardware type. Used in diagnostics and
65           sometimes configuration.
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67       dev
68           Driver model state for this abstract device.
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DESCRIPTION

71       Gadgets have a mostly-portable “gadget driver” implementing device
72       functions, handling all usb configurations and interfaces. Gadget
73       drivers talk to hardware-specific code indirectly, through ops vectors.
74       That insulates the gadget driver from hardware details, and packages
75       the hardware endpoints through generic i/o queues. The “usb_gadget” and
76       “usb_ep” interfaces provide that insulation from the hardware.
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78       Except for the driver data, all fields in this structure are read-only
79       to the gadget driver. That driver data is part of the “driver model”
80       infrastructure in 2.6 (and later) kernels, and for earlier systems is
81       grouped in a similar structure that´s not known to the rest of the
82       kernel.
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84       Values of the three OTG device feature flags are updated before the
85       setup call corresponding to USB_REQ_SET_CONFIGURATION, and before
86       driver suspend calls. They are valid only when is_otg, and when the
87       device is acting as a B-Peripheral (so is_a_peripheral is false).
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AUTHOR

90       David Brownell <dbrownell@users.sourceforge.net>
91           Author.
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94Kernel Hackers Manual 2.6.         June 2019              STRUCT USB_GADGET(9)
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