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usb_string_ids_tab(9) [centos man page]

USB_STRING_IDS_TAB(9)					      Kernel Mode Gadget API					     USB_STRING_IDS_TAB(9)

usb_string_ids_tab - allocate unused string IDs in batch SYNOPSIS
int usb_string_ids_tab(struct usb_composite_dev * cdev, struct usb_string * str); ARGUMENTS
cdev the device whose string descriptor IDs are being allocated str an array of usb_string objects to assign numbers to CONTEXT
single threaded during gadget setup DESCRIPTION
usb_string_ids() is called from bind callbacks to allocate string IDs. Drivers for functions, configurations, or gadgets will then copy IDs from the string table to the appropriate descriptors and string table for other languages. All string identifier should be allocated using this, usb_string_id() or usb_string_ids_n() routine, to ensure that for example different functions don't wrongly assign different meanings to the same identifier. AUTHOR
David Brownell <> Author. COPYRIGHT
Kernel Hackers Manual 3.10 June 2014 USB_STRING_IDS_TAB(9)

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struct_usb_configuration - represents one gadget configuration SYNOPSIS
struct usb_configuration { const char * label; struct usb_gadget_strings ** strings; const struct usb_descriptor_header ** descriptors; int (* bind) (struct usb_configuration *); void (* unbind) (struct usb_configuration *); int (* setup) (struct usb_configuration *,const struct usb_ctrlrequest *); u8 bConfigurationValue; u8 iConfiguration; u8 bmAttributes; u8 bMaxPower; struct usb_composite_dev * cdev; }; MEMBERS
label For diagnostics, describes the configuration. strings Tables of strings, keyed by identifiers assigned during bind() and by language IDs provided in control requests. descriptors Table of descriptors preceding all function descriptors. Examples include OTG and vendor-specific descriptors. bind Called from usb_add_config() to allocate resources unique to this configuration and to call usb_add_function() for each function used. unbind Reverses bind; called as a side effect of unregistering the driver which added this configuration. setup Used to delegate control requests that aren't handled by standard device infrastructure or directed at a specific interface. bConfigurationValue Copied into configuration descriptor. iConfiguration Copied into configuration descriptor. bmAttributes Copied into configuration descriptor. bMaxPower Copied into configuration descriptor. cdev assigned by usb_add_config() before calling bind(); this is the device associated with this configuration. DESCRIPTION
Configurations are building blocks for gadget drivers structured around function drivers. Simple USB gadgets require only one function and one configuration, and handle dual-speed hardware by always providing the same functionality. Slightly more complex gadgets may have more than one single-function configuration at a given speed; or have configurations that only work at one speed. Composite devices are, by definition, ones with configurations which include more than one function. The lifecycle of a usb_configuration includes allocation, initialization of the fields described above, and calling usb_add_config() to set up internal data and bind it to a specific device. The configuration's bind() method is then used to initialize all the functions and then call usb_add_function() for them. Those functions would normally be independant of each other, but that's not mandatory. CDC WMC devices are an example where functions often depend on other functions, with some functions subsidiary to others. Such interdependency may be managed in any way, so long as all of the descriptors complete by the time the composite driver returns from its bind routine. AUTHOR
David Brownell <> Author. COPYRIGHT
Kernel Hackers Manual 2.6. July 2010 STRUCT USB_CONFIGURA(9)
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