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/*

 * <linux/usb_gadget.h>

 *

 * We call the USB code inside a Linux-based peripheral device a "gadget"

 * driver, except for the hardware-specific bus glue.  One USB host can

 * master many USB gadgets, but the gadgets are only slaved to one host.

 *

 *

 * (c) Copyright 2002-2003 by David Brownell

 * All Rights Reserved.

 *

 * This software is licensed under the GNU GPL version 2.

 */

#ifndef __LINUX_USB_GADGET_H

#define __LINUX_USB_GADGET_H

#ifdef __KERNEL__

struct usb_ep;

/**

 * struct usb_request - describes one i/o request

 * @buf: Buffer used for data.  Always provide this; some controllers

 *      only use PIO, or don't use DMA for some endpoints.

 * @dma: DMA address corresponding to 'buf'.  If you don't set this

 *      field, and the usb controller needs one, it is responsible

 *      for mapping and unmapping the buffer.

 * @length: Length of that data

 * @no_interrupt: If true, hints that no completion irq is needed.

 *      Helpful sometimes with deep request queues.

 * @zero: If true, when writing data, makes the last packet be "short"

 *     by adding a zero length packet as needed;

 * @short_not_ok: When reading data, makes short packets be

 *     treated as errors (queue stops advancing till cleanup).

 * @complete: Function called when request completes

 * @context: For use by the completion callback

 * @list: For use by the gadget driver.

 * @status: Reports completion code, zero or a negative errno.

 *      Normally, faults block the transfer queue from advancing until

 *      the completion callback returns.

 *      Code "-ESHUTDOWN" indicates completion caused by device disconnect,

 *      or when the driver disabled the endpoint.

 * @actual: Reports actual bytes transferred.  For reads (OUT

 *      transfers) this may be less than the requested length.  If the

 *      short_not_ok flag is set, short reads are treated as errors

 *      even when status otherwise indicates successful completion.

 *      Note that for writes (IN transfers) the data bytes may still

 *      reside in a device-side FIFO.

 *

 * These are allocated/freed through the endpoint they're used with.  The

 * hardware's driver can add extra per-request data to the memory it returns,

 * which often avoids separate memory allocations (potential failures),

 * later when the request is queued.

 *

 * Request flags affect request handling, such as whether a zero length

 * packet is written (the "zero" flag), whether a short read should be

 * treated as an error (blocking request queue advance, the "short_not_ok"

 * flag), or hinting that an interrupt is not required (the "no_interrupt"

 * flag, for use with deep request queues).

 *

 * Bulk endpoints can use any size buffers, and can also be used for interrupt

 * transfers. interrupt-only endpoints can be much less functional.

 */

        // NOTE this is analagous to 'struct urb' on the host side,

        // except that it's thinner and promotes more pre-allocation.

        //

        // ISSUE should this be allocated through the device?

struct usb_request {

        void                    *buf;

        unsigned                length;

        dma_addr_t              dma;

        unsigned                no_interrupt:1;

        unsigned                zero:1;

        unsigned                short_not_ok:1;

        void                    (*complete)(struct usb_ep *ep,

                                        struct usb_request *req);

        void                    *context;

        struct list_head        list;

        int                     status;

        unsigned                actual;

};

/*-------------------------------------------------------------------------*/

/* endpoint-specific parts of the api to the usb controller hardware.

 * unlike the urb model, (de)multiplexing layers are not required.

 * (so this api could slash overhead if used on the host side...)

 *

 * note that device side usb controllers commonly differ in how many

 * endpoints they support, as well as their capabilities.

 */

struct usb_ep_ops {

        int (*enable) (struct usb_ep *ep,

                const struct usb_endpoint_descriptor *desc);

        int (*disable) (struct usb_ep *ep);

        struct usb_request *(*alloc_request) (struct usb_ep *ep,

                int gfp_flags);

        void (*free_request) (struct usb_ep *ep, struct usb_request *req);

        void *(*alloc_buffer) (struct usb_ep *ep, unsigned bytes,

                dma_addr_t *dma, int gfp_flags);

        void (*free_buffer) (struct usb_ep *ep, void *buf, dma_addr_t dma,

                unsigned bytes);

        // NOTE:  on 2.5, drivers may also use dma_map() and

        // dma_sync_single() to manage dma overhead. 

        int (*queue) (struct usb_ep *ep, struct usb_request *req,

                int gfp_flags);

        int (*dequeue) (struct usb_ep *ep, struct usb_request *req);

        int (*set_halt) (struct usb_ep *ep, int value);

        int (*fifo_status) (struct usb_ep *ep);

        void (*fifo_flush) (struct usb_ep *ep);

};

/**

 * struct usb_ep - device side representation of USB endpoint

 * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk"

 * @ops: Function pointers used to access hardware-specific operations.

 * @ep_list:the gadget's ep_list holds all of its endpoints

 * @maxpacket:The maximum packet size used on this endpoint.  The initial

 *      value can sometimes be reduced (hardware allowing), according to

 *      the endpoint descriptor used to configure the endpoint.

 * @driver_data:for use by the gadget driver.  all other fields are

 *      read-only to gadget drivers.

 *

 * the bus controller driver lists all the general purpose endpoints in

 * gadget->ep_list.  the control endpoint (gadget->ep0) is not in that list,

 * and is accessed only in response to a driver setup() callback.

 */

struct usb_ep {

        void                    *driver_data;

        const char              *name;

        const struct usb_ep_ops *ops;

        struct list_head        ep_list;

        unsigned                maxpacket:16;

};

/*-------------------------------------------------------------------------*/

/**

 * usb_ep_enable - configure endpoint, making it usable

 * @ep:the endpoint being configured.  may not be the endpoint named "ep0".

 *      drivers discover endpoints through the ep_list of a usb_gadget.

 * @desc:descriptor for desired behavior.  caller guarantees this pointer

 *      remains valid until the endpoint is disabled; the data byte order

 *      is little-endian (usb-standard).

 *

 * when configurations are set, or when interface settings change, the driver

 * will enable or disable the relevant endpoints.  while it is enabled, an

 * endpoint may be used for i/o until the driver receives a disconnect() from

 * the host or until the endpoint is disabled.

 *

 * the ep0 implementation (which calls this routine) must ensure that the

 * hardware capabilities of each endpoint match the descriptor provided

 * for it.  for example, an endpoint named "ep2in-bulk" would be usable

 * for interrupt transfers as well as bulk, but it likely couldn't be used

 * for iso transfers or for endpoint 14.  some endpoints are fully

 * configurable, with more generic names like "ep-a".  (remember that for

 * USB, "in" means "towards the USB master".)

 *

 * returns zero, or a negative error code.

 */

static inline int

usb_ep_enable (struct usb_ep *ep, const struct usb_endpoint_descriptor *desc)

{

        return ep->ops->enable (ep, desc);

}

/**

 * usb_ep_disable - endpoint is no longer usable

 * @ep:the endpoint being unconfigured.  may not be the endpoint named "ep0".

 *

 * no other task may be using this endpoint when this is called.

 * any pending and uncompleted requests will complete with status

 * indicating disconnect (-ESHUTDOWN) before this call returns.

 * gadget drivers must call usb_ep_enable() again before queueing

 * requests to the endpoint.

 *

 * returns zero, or a negative error code.

 */

static inline int

usb_ep_disable (struct usb_ep *ep)

{

        return ep->ops->disable (ep);

}

/**

 * usb_ep_alloc_request - allocate a request object to use with this endpoint

 * @ep:the endpoint to be used with with the request

 * @gfp_flags:GFP_* flags to use

 *

 * Request objects must be allocated with this call, since they normally

 * need controller-specific setup and may even need endpoint-specific

 * resources such as allocation of DMA descriptors.

 * Requests may be submitted with usb_ep_queue(), and receive a single

 * completion callback.  Free requests with usb_ep_free_request(), when

 * they are no longer needed.

 *

 * Returns the request, or null if one could not be allocated.

 */

static inline struct usb_request *

usb_ep_alloc_request (struct usb_ep *ep, int gfp_flags)

{

        return ep->ops->alloc_request (ep, gfp_flags);

}

/**

 * usb_ep_free_request - frees a request object

 * @ep:the endpoint associated with the request

 * @req:the request being freed

 *

 * Reverses the effect of usb_ep_alloc_request().

 * Caller guarantees the request is not queued, and that it will

 * no longer be requeued (or otherwise used).

 */

static inline void

usb_ep_free_request (struct usb_ep *ep, struct usb_request *req)

{

        ep->ops->free_request (ep, req);

}

/**

 * usb_ep_alloc_buffer - allocate an I/O buffer

 * @ep:the endpoint associated with the buffer

 * @len:length of the desired buffer

 * @dma:pointer to the buffer's DMA address; must be valid

 * @gfp_flags:GFP_* flags to use

 *

 * Returns a new buffer, or null if one could not be allocated.

 * The buffer is suitably aligned for dma, if that endpoint uses DMA,

 * and the caller won't have to care about dma-inconsistency

 * or any hidden "bounce buffer" mechanism.  No additional per-request

 * DMA mapping will be required for such buffers.

 * Free it later with usb_ep_free_buffer().

 *

 * You don't need to use this call to allocate I/O buffers unless you

 * want to make sure drivers don't incur costs for such "bounce buffer"

 * copies or per-request DMA mappings.

 */

static inline void *

usb_ep_alloc_buffer (struct usb_ep *ep, unsigned len, dma_addr_t *dma,

        int gfp_flags)

{

        return ep->ops->alloc_buffer (ep, len, dma, gfp_flags);

}

/**

 * usb_ep_free_buffer - frees an i/o buffer

 * @ep:the endpoint associated with the buffer

 * @buf:CPU view address of the buffer

 * @dma:the buffer's DMA address

 * @len:length of the buffer

 *

 * reverses the effect of usb_ep_alloc_buffer().

 * caller guarantees the buffer will no longer be accessed

 */

static inline void

usb_ep_free_buffer (struct usb_ep *ep, void *buf, dma_addr_t dma, unsigned len)

{

        ep->ops->free_buffer (ep, buf, dma, len);

}

/**

 * usb_ep_queue - queues (submits) an I/O request to an endpoint.

 * @ep:the endpoint associated with the request

 * @req:the request being submitted

 * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't

 *      pre-allocate all necessary memory with the request.

 *

 * This tells the device controller to perform the specified request through

 * that endpoint (reading or writing a buffer).  When the request completes,

 * including being canceled by usb_ep_dequeue(), the request's completion

 * routine is called to return the request to the driver.  Any endpoint

 * (except control endpoints like ep0) may have more than one transfer

 * request queued; they complete in FIFO order.  Once a gadget driver

 * submits a request, that request may not be examined or modified until it

 * is given back to that driver through the completion callback.

 *

 * Each request is turned into one or more packets.  The controller driver

 * never merges adjacent requests into the same packet.  OUT transfers

 * will sometimes use data that's already buffered in the hardware.

 *

 * Bulk endpoints can queue any amount of data; the transfer is packetized

 * automatically.  The last packet will be short if the request doesn't fill it

 * out completely.  Zero length packets (ZLPs) should be avoided in portable

 * protocols since not all usb hardware can successfully handle zero length

 * packets.  (ZLPs may be explicitly written, and may be implicitly written if

 * the request 'zero' flag is set.)  Bulk endpoints may also be used

 * for interrupt transfers; but the reverse is not true, and some endpoints

 * won't support every interrupt transfer.  (Such as 768 byte packets.)

 *

 * Interrupt-only endpoints are less functional than bulk endpoints, for

 * example by not supporting queueing or not handling buffers that are

 * larger than the endpoint's maxpacket size.  They may also treat data

 * toggle differently.

 *

 * Control endpoints ... after getting a setup() callback, the driver queues

 * one response (even if it would be zero length).  That enables the

 * status ack, after transfering data as specified in the response.  Setup

 * functions may return negative error codes to generate protocol stalls.

 * (Note that some USB device controllers disallow protocol stall responses

 * in some cases.)  When control responses are deferred (the response is

 * written after the setup callback returns), then usb_ep_set_halt() may be

 * used on ep0 to trigger protocol stalls.

 *

 * For periodic endpoints, like interrupt or isochronous ones, the usb host

 * arranges to poll once per interval, and the gadget driver usually will

 * have queued some data to transfer at that time.

 *

 * Returns zero, or a negative error code.  Endpoints that are not enabled

 * report errors; errors will also be

 * reported when the usb peripheral is disconnected.

 */

static inline int

usb_ep_queue (struct usb_ep *ep, struct usb_request *req, int gfp_flags)

{

        return ep->ops->queue (ep, req, gfp_flags);

}

/**

 * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint

 * @ep:the endpoint associated with the request

 * @req:the request being canceled

 *

 * if the request is still active on the endpoint, it is dequeued and its

 * completion routine is called (with status -ECONNRESET); else a negative

 * error code is returned.

 *

 * note that some hardware can't clear out write fifos (to unlink the request

 * at the head of the queue) except as part of disconnecting from usb.  such

 * restrictions prevent drivers from supporting configuration changes,

 * even to configuration zero (a "chapter 9" requirement).

 */

static inline int usb_ep_dequeue (struct usb_ep *ep, struct usb_request *req)

{

        return ep->ops->dequeue (ep, req);

}

/**

 * usb_ep_set_halt - sets the endpoint halt feature.

 * @ep: the non-isochronous endpoint being stalled

 *

 * Use this to stall an endpoint, perhaps as an error report.

 * Except for control endpoints,

 * the endpoint stays halted (will not stream any data) until the host

 * clears this feature; drivers may need to empty the endpoint's request

 * queue first, to make sure no inappropriate transfers happen.

 *

 * Note that while an endpoint CLEAR_FEATURE will be invisible to the

 * gadget driver, a SET_INTERFACE will not be.  To reset endpoints for the

 * current altsetting, see usb_ep_clear_halt().  When switching altsettings,

 * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.

 *

 * Returns zero, or a negative error code.  On success, this call sets

 * underlying hardware state that blocks data transfers.

 */

static inline int

usb_ep_set_halt (struct usb_ep *ep)

{

        return ep->ops->set_halt (ep, 1);

}

/**

 * usb_ep_clear_halt - clears endpoint halt, and resets toggle

 * @ep:the bulk or interrupt endpoint being reset

 *

 * Use this when responding to the standard usb "set interface" request,

 * for endpoints that aren't reconfigured, after clearing any other state

 * in the endpoint's i/o queue.

 *

 * Returns zero, or a negative error code.  On success, this call clears

 * the underlying hardware state reflecting endpoint halt and data toggle.

 * Note that some hardware can't support this request (like pxa2xx_udc),

 * and accordingly can't correctly implement interface altsettings.

 */

static inline int

usb_ep_clear_halt (struct usb_ep *ep)

{

        return ep->ops->set_halt (ep, 0);

}

/**

 * usb_ep_fifo_status - returns number of bytes in fifo, or error

 * @ep: the endpoint whose fifo status is being checked.

 *

 * FIFO endpoints may have "unclaimed data" in them in certain cases,

 * such as after aborted transfers.  Hosts may not have collected all

 * the IN data written by the gadget driver, as reported by a request

 * completion.  The gadget driver may not have collected all the data

 * written OUT to it by the host.  Drivers that need precise handling for

 * fault reporting or recovery may need to use this call.

 *

 * This returns the number of such bytes in the fifo, or a negative

 * errno if the endpoint doesn't use a FIFO or doesn't support such

 * precise handling.

 */

static inline int

usb_ep_fifo_status (struct usb_ep *ep)

{

        if (ep->ops->fifo_status)

                return ep->ops->fifo_status (ep);

        else

                return -EOPNOTSUPP;

}

/**

 * usb_ep_fifo_flush - flushes contents of a fifo

 * @ep: the endpoint whose fifo is being flushed.

 *

 * This call may be used to flush the "unclaimed data" that may exist in

 * an endpoint fifo after abnormal transaction terminations.  The call

 * must never be used except when endpoint is not being used for any

 * protocol translation.

 */

static inline void

usb_ep_fifo_flush (struct usb_ep *ep)

{

        if (ep->ops->fifo_flush)

                ep->ops->fifo_flush (ep);

}

/*-------------------------------------------------------------------------*/

struct usb_gadget;

/* the rest of the api to the controller hardware: device operations,

 * which don't involve endpoints (or i/o).

 */

struct usb_gadget_ops {

        int     (*get_frame)(struct usb_gadget *);

        int     (*wakeup)(struct usb_gadget *);

        int     (*set_selfpowered) (struct usb_gadget *, int value);

        int     (*ioctl)(struct usb_gadget *,

                                unsigned code, unsigned long param);

};

/**

 * struct usb_gadget - represents a usb slave device

 * @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.

 * @name: Identifies the controller hardware type.  Used in diagnostics

 *      and sometimes configuration.

 * @dev: Driver model state for this abstract device.

 *

 * 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 2.5 (and later) kernels, and for

 * earlier systems is grouped in a similar structure that's not known

 * to the rest of the kernel.

 */

struct usb_gadget {

        /* readonly to gadget driver */

        const struct usb_gadget_ops     *ops;

        struct usb_ep                   *ep0;

        struct list_head                ep_list;        /* of usb_ep */

        enum usb_device_speed           speed;

        const char                      *name;

        struct device                   dev;

};

static inline void set_gadget_data (struct usb_gadget *gadget, void *data)

        { dev_set_drvdata (&gadget->dev, data); }

static inline void *get_gadget_data (struct usb_gadget *gadget)

        { return dev_get_drvdata (&gadget->dev); }

/* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */

#define gadget_for_each_ep(tmp,gadget) \

        list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)

/**

 * usb_gadget_frame_number - returns the current frame number

 * @gadget: controller that reports the frame number

 *

 * Returns the usb frame number, normally eleven bits from a SOF packet,

 * or negative errno if this device doesn't support this capability.

 */

static inline int usb_gadget_frame_number (struct usb_gadget *gadget)

{

        return gadget->ops->get_frame (gadget);

}

/**

 * usb_gadget_wakeup - tries to wake up the host connected to this gadget

 * @gadget: controller used to wake up the host

 *

 * Returns zero on success, else negative error code if the hardware

 * doesn't support such attempts, or its support has not been enabled

 * by the usb host.  Drivers must return device descriptors that report

 * their ability to support this, or hosts won't enable it.

 */

static inline int usb_gadget_wakeup (struct usb_gadget *gadget)

{

        if (!gadget->ops->wakeup)

                return -EOPNOTSUPP;

        return gadget->ops->wakeup (gadget);

}

/**

 * usb_gadget_set_selfpowered - sets the device selfpowered feature.

 * @gadget:the device being declared as self-powered

 *

 * this affects the device status reported by the hardware driver

 * to reflect that it now has a local power supply.

 *

 * returns zero on success, else negative errno.

 */

static inline int

usb_gadget_set_selfpowered (struct usb_gadget *gadget)

{

        if (!gadget->ops->set_selfpowered)

                return -EOPNOTSUPP;

        return gadget->ops->set_selfpowered (gadget, 1);

}

/**

 * usb_gadget_clear_selfpowered - clear the device selfpowered feature.

 * @gadget:the device being declared as bus-powered

 *

 * this affects the device status reported by the hardware driver.

 * some hardware may not support bus-powered operation, in which

 * case this feature's value can never change.

 *

 * returns zero on success, else negative errno.

 */

static inline int

usb_gadget_clear_selfpowered (struct usb_gadget *gadget)

{

        if (!gadget->ops->set_selfpowered)

                return -EOPNOTSUPP;

        return gadget->ops->set_selfpowered (gadget, 0);

}

/*-------------------------------------------------------------------------*/

/**

 * struct usb_gadget_driver - driver for usb 'slave' devices

 * @function: String describing the gadget's function

 * @speed: Highest speed the driver handles.

 * @bind: Invoked when the driver is bound to a gadget, usually

 *      after registering the driver.

 *      At that point, ep0 is fully initialized, and ep_list holds

 *      the currently-available endpoints.

 *      Called in a context that permits sleeping.

 * @setup: Invoked for ep0 control requests that aren't handled by

 *      the hardware level driver. Most calls must be handled by

 *      the gadget driver, including descriptor and configuration

 *      management.  The 16 bit members of the setup data are in

 *      cpu order. Called in_interrupt; this may not sleep.  Driver

 *      queues a response to ep0, or returns negative to stall.

 * @disconnect: Invoked after all transfers have been stopped,

 *      when the host is disconnected.  May be called in_interrupt; this

 *      may not sleep.  Some devices can't detect disconnect, so this might

 *      not be called except as part of controller shutdown.

 * @unbind: Invoked when the driver is unbound from a gadget,

 *      usually from rmmod (after a disconnect is reported).

 *      Called in a context that permits sleeping.

 * @suspend: Invoked on USB suspend.  May be called in_interrupt.

 * @resume: Invoked on USB resume.  May be called in_interrupt.

 * @driver: Driver model state for this driver.

 *

 * Devices are disabled till a gadget driver successfully bind()s, which

 * means the driver will handle setup() requests needed to enumerate (and

 * meet "chapter 9" requirements) then do some useful work.

 *

 * Drivers use hardware-specific knowledge to configure the usb hardware.

 * endpoint addressing is only one of several hardware characteristics that

 * are in descriptors the ep0 implementation returns from setup() calls.

 *

 * Except for ep0 implementation, most driver code shouldn't need change to

 * run on top of different usb controllers.  It'll use endpoints set up by

 * that ep0 implementation.

 *

 * The usb controller driver handles a few standard usb requests.  Those

 * include set_address, and feature flags for devices, interfaces, and

 * endpoints (the get_status, set_feature, and clear_feature requests).

 *

 * Accordingly, the driver's setup() callback must always implement all

 * get_descriptor requests, returning at least a device descriptor and

 * a configuration descriptor.  Drivers must make sure the endpoint

 * descriptors match any hardware constraints. Some hardware also constrains

 * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).

 *

 * The driver's setup() callback must also implement set_configuration,

 * and should also implement set_interface, get_configuration, and

 * get_interface.  Setting a configuration (or interface) is where

 * endpoints should be activated or (config 0) shut down.

 *

 * (Note that only the default control endpoint is supported.  Neither

 * hosts nor devices generally support control traffic except to ep0.)

 *

 * Most devices will ignore USB suspend/resume operations, and so will

 * not provide those callbacks.  However, some may need to change modes

 * when the host is not longer directing those activities.  For example,

 * local controls (buttons, dials, etc) may need to be re-enabled since

 * the (remote) host can't do that any longer; or an error state might

 * be cleared, to make the device behave identically whether or not

 * power is maintained.

 */

struct usb_gadget_driver {

        char                    *function;

        enum usb_device_speed   speed;

        int                     (*bind)(struct usb_gadget *);

        void                    (*unbind)(struct usb_gadget *);

        int                     (*setup)(struct usb_gadget *,

                                        const struct usb_ctrlrequest *);

        void                    (*disconnect)(struct usb_gadget *);

        void                    (*suspend)(struct usb_gadget *);

        void                    (*resume)(struct usb_gadget *);

        // FIXME support safe rmmod

        struct device_driver    driver;

};

/*-------------------------------------------------------------------------*/

/* driver modules register and unregister, as usual.

 * these calls must be made in a context that can sleep.

 *

 * these will usually be implemented directly by the hardware-dependent

 * usb bus interface driver, which will only support a single driver.

 */

/**

 * usb_gadget_register_driver - register a gadget driver

 * @driver:the driver being registered

 *

 * Call this in your gadget driver's module initialization function,

 * to tell the underlying usb controller driver about your driver.

 * The driver's bind() function will be called to bind it to a

 * gadget.  This function must be called in a context that can sleep.

 */

int usb_gadget_register_driver (struct usb_gadget_driver *driver);

/**

 * usb_gadget_unregister_driver - unregister a gadget driver

 * @driver:the driver being unregistered

 *

 * Call this in your gadget driver's module cleanup function,

 * to tell the underlying usb controller that your driver is

 * going away.  If the controller is connected to a USB host,

 * it will first disconnect().  The driver is also requested

 * to unbind() and clean up any device state, before this procedure

 * finally returns.

 * This function must be called in a context that can sleep.

 */

int usb_gadget_unregister_driver (struct usb_gadget_driver *driver);

/*-------------------------------------------------------------------------*/

/* utility to simplify dealing with string descriptors */

/**

 * struct usb_string - wraps a C string and its USB id

 * @id:the (nonzero) ID for this string

 * @s:the string, in ISO-8859/1 characters

 *

 * If you're using usb_gadget_get_string(), use this to wrap a string

 * together with its ID.

 */

struct usb_string {

        u8                      id;

        const char              *s;

};

/**

 * struct usb_gadget_strings - a set of USB strings in a given language

 * @language:identifies the strings' language (0x0409 for en-us)

 * @strings:array of strings with their ids

 *

 * If you're using usb_gadget_get_string(), use this to wrap all the

 * strings for a given language.

 */

struct usb_gadget_strings {

        u16                     language;       /* 0x0409 for en-us */

        struct usb_string       *strings;

};

/* put descriptor for string with that id into buf (buflen >= 256) */

int usb_gadget_get_string (struct usb_gadget_strings *table, int id, u8 *buf);

#endif  /* __KERNEL__ */

#endif  /* __LINUX_USB_GADGET_H */