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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>struct usb_gadget</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="USB Gadget API for Linux" /><link rel="up" href="ch03s03.html" title="Core Objects and Methods" /><link rel="prev" href="re28.html" title="usb_ep_fifo_flush" /><link rel="next" href="re30.html" title="gadget_is_dualspeed" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>struct usb_gadget</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="re28.html">Prev</a> </td><th width="60%" align="center">Core Objects and Methods</th><td width="20%" align="right"> <a accesskey="n" href="re30.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="struct usb_gadget"><a id="API-struct-usb-gadget"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>struct usb_gadget —
represents a usb slave device
</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><pre class="programlisting">
struct usb_gadget {
const struct usb_gadget_ops * ops;
struct usb_ep * ep0;
struct list_head ep_list;
enum usb_device_speed speed;
unsigned is_dualspeed: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;
}; </pre></div><div class="refsect1" title="Members"><a id="id2994361"></a><h2>Members</h2><div class="variablelist"><dl><dt><span class="term">ops</span></dt><dd><p>
Function pointers used to access hardware-specific operations.
</p></dd><dt><span class="term">ep0</span></dt><dd><p>
Endpoint zero, used when reading or writing responses to
driver <code class="function">setup</code> requests
</p></dd><dt><span class="term">ep_list</span></dt><dd><p>
List of other endpoints supported by the device.
</p></dd><dt><span class="term">speed</span></dt><dd><p>
Speed of current connection to USB host.
</p></dd><dt><span class="term">is_dualspeed</span></dt><dd><p>
True if the controller supports both high and full speed
operation. If it does, the gadget driver must also support both.
</p></dd><dt><span class="term">is_otg</span></dt><dd><p>
True if the USB device port uses a Mini-AB jack, so that the
gadget driver must provide a USB OTG descriptor.
</p></dd><dt><span class="term">is_a_peripheral</span></dt><dd><p>
False unless is_otg, the <span class="quote">“<span class="quote">A</span>”</span> end of a USB cable
is in the Mini-AB jack, and HNP has been used to switch roles
so that the <span class="quote">“<span class="quote">A</span>”</span> device currently acts as A-Peripheral, not A-Host.
</p></dd><dt><span class="term">b_hnp_enable</span></dt><dd><p>
OTG device feature flag, indicating that the A-Host
enabled HNP support.
</p></dd><dt><span class="term">a_hnp_support</span></dt><dd><p>
OTG device feature flag, indicating that the A-Host
supports HNP at this port.
</p></dd><dt><span class="term">a_alt_hnp_support</span></dt><dd><p>
OTG device feature flag, indicating that the A-Host
only supports HNP on a different root port.
</p></dd><dt><span class="term">name</span></dt><dd><p>
Identifies the controller hardware type. Used in diagnostics
and sometimes configuration.
</p></dd><dt><span class="term">dev</span></dt><dd><p>
Driver model state for this abstract device.
</p></dd></dl></div></div><div class="refsect1" title="Description"><a id="id2994531"></a><h2>Description</h2><p>
Gadgets have a mostly-portable <span class="quote">“<span class="quote">gadget driver</span>”</span> 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 <span class="quote">“<span class="quote">usb_gadget</span>”</span>
and <span class="quote">“<span class="quote">usb_ep</span>”</span> interfaces provide that insulation from the hardware.
</p><p>
Except for the driver data, all fields in this structure are
read-only to the gadget driver. That driver data is part of the
<span class="quote">“<span class="quote">driver model</span>”</span> 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.
</p><p>
Values of the three OTG device feature flags are updated before the
<code class="function">setup</code> call corresponding to USB_REQ_SET_CONFIGURATION, and before
driver <code class="function">suspend</code> calls. They are valid only when is_otg, and when the
device is acting as a B-Peripheral (so is_a_peripheral is false).
</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="re28.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch03s03.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="re30.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span>usb_ep_fifo_flush</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span>gadget_is_dualspeed</span></td></tr></table></div></body></html>
