xref: /device/soc/rockchip/common/sdk_linux/include/linux/usb/composite.h

// SPDX-License-Identifier: GPL-2.0+
/*
 * composite.h -- framework for usb gadgets which are composite devices
 *
 * Copyright (C) 2006-2008 David Brownell
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef __LINUX_USB_COMPOSITE_H
#define __LINUX_USB_COMPOSITE_H

/*
 * This framework is an optional layer on top of the USB Gadget interface,
 * making it easier to build (a) Composite devices, supporting multiple
 * functions within any single configuration, and (b) Multi-configuration
 * devices, also supporting multiple functions but without necessarily
 * having more than one function per configuration.
 *
 * Example:  a device with a single configuration supporting both network
 * link and mass storage functions is a composite device.  Those functions
 * might alternatively be packaged in individual configurations, but in
 * the composite model the host can use both functions at the same time.
 */

#include <linux/bcd.h>
#include <linux/version.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
#include <linux/log2.h>
#include <linux/configfs.h>

/*
 * USB function drivers should return USB_GADGET_DELAYED_STATUS if they
 * wish to delay the data/status stages of the control transfer till they
 * are ready. The control transfer will then be kept from completing till
 * all the function drivers that requested for USB_GADGET_DELAYED_STAUS
 * invoke usb_composite_setup_continue().
 */
#define USB_GADGET_DELAYED_STATUS 0x7fff /* Impossibly large value */

/* big enough to hold our biggest descriptor */
#define USB_COMP_EP0_BUFSIZ 4096

/* OS feature descriptor length <= 4kB */
#define USB_COMP_EP0_OS_DESC_BUFSIZ 4096

#define USB_MS_TO_HS_INTERVAL(x) (ilog2(((x)*1000 / 125)) + 1)
struct usb_configuration;

/**
 * struct usb_os_desc_ext_prop - describes one "Extended Property"
 * @entry: used to keep a list of extended properties
 * @type: Extended Property type
 * @name_len: Extended Property unicode name length, including terminating '\0'
 * @name: Extended Property name
 * @data_len: Length of Extended Property blob (for unicode store double len)
 * @data: Extended Property blob
 * @item: Represents this Extended Property in configfs
 */
struct usb_os_desc_ext_prop {
    struct list_head entry;
    u8 type;
    int name_len;
    char *name;
    int data_len;
    char *data;
    struct config_item item;
};

/**
 * struct usb_os_desc - describes OS descriptors associated with one interface
 * @ext_compat_id: 16 bytes of "Compatible ID" and "Subcompatible ID"
 * @ext_prop: Extended Properties list
 * @ext_prop_len: Total length of Extended Properties blobs
 * @ext_prop_count: Number of Extended Properties
 * @opts_mutex: Optional mutex protecting config data of a usb_function_instance
 * @group: Represents OS descriptors associated with an interface in configfs
 * @owner: Module associated with this OS descriptor
 */
struct usb_os_desc {
    char *ext_compat_id;
    struct list_head ext_prop;
    int ext_prop_len;
    int ext_prop_count;
    struct mutex *opts_mutex;
    struct config_group group;
    struct module *owner;
};

/**
 * struct usb_os_desc_table - describes OS descriptors associated with one
 * interface of a usb_function
 * @if_id: Interface id
 * @os_desc: "Extended Compatibility ID" and "Extended Properties" of the
 *    interface
 *
 * Each interface can have at most one "Extended Compatibility ID" and a
 * number of "Extended Properties".
 */
struct usb_os_desc_table {
    int if_id;
    struct usb_os_desc *os_desc;
};

/**
 * struct usb_function - describes one function of a configuration
 * @name: For diagnostics, identifies the function.
 * @strings: tables of strings, keyed by identifiers assigned during bind()
 *    and by language IDs provided in control requests
 * @fs_descriptors: Table of full (or low) speed descriptors, using interface and
 *    string identifiers assigned during @bind().  If this pointer is null,
 *    the function will not be available at full speed (or at low speed).
 * @hs_descriptors: Table of high speed descriptors, using interface and
 *    string identifiers assigned during @bind().  If this pointer is null,
 *    the function will not be available at high speed.
 * @ss_descriptors: Table of super speed descriptors, using interface and
 *    string identifiers assigned during @bind(). If this
 *    pointer is null after initiation, the function will not
 *    be available at super speed.
 * @ssp_descriptors: Table of super speed plus descriptors, using
 *    interface and string identifiers assigned during @bind(). If
 *    this pointer is null after initiation, the function will not
 *    be available at super speed plus.
 * @config: assigned when @usb_add_function() is called; this is the
 *    configuration with which this function is associated.
 * @os_desc_table: Table of (interface id, os descriptors) pairs. The function
 *    can expose more than one interface. If an interface is a member of
 *    an IAD, only the first interface of IAD has its entry in the table.
 * @os_desc_n: Number of entries in os_desc_table
 * @bind: Before the gadget can register, all of its functions bind() to the
 *    available resources including string and interface identifiers used
 *    in interface or class descriptors; endpoints; I/O buffers; and so on.
 * @unbind: Reverses @bind; called as a side effect of unregistering the
 *    driver which added this function.
 * @free_func: free the struct usb_function.
 * @mod: (internal) points to the module that created this structure.
 * @set_alt: (REQUIRED) Reconfigures altsettings; function drivers may
 *    initialize usb_ep.driver data at this time (when it is used).
 *    Note that setting an interface to its current altsetting resets
 *    interface state, and that all interfaces have a disabled state.
 * @get_alt: Returns the active altsetting.  If this is not provided,
 *    then only altsetting zero is supported.
 * @disable: (REQUIRED) Indicates the function should be disabled.  Reasons
 *    include host resetting or reconfiguring the gadget, and disconnection.
 * @setup: Used for interface-specific control requests.
 * @req_match: Tests if a given class request can be handled by this function.
 * @suspend: Notifies functions when the host stops sending USB traffic.
 * @resume: Notifies functions when the host restarts USB traffic.
 * @get_status: Returns function status as a reply to
 *    GetStatus() request when the recipient is Interface.
 * @func_suspend: callback to be called when
 *    SetFeature(FUNCTION_SUSPEND) is reseived
 *
 * A single USB function uses one or more interfaces, and should in most
 * cases support operation at both full and high speeds.  Each function is
 * associated by @usb_add_function() with a one configuration; that function
 * causes @bind() to be called so resources can be allocated as part of
 * setting up a gadget driver.  Those resources include endpoints, which
 * should be allocated using @usb_ep_autoconfig().
 *
 * To support dual speed operation, a function driver provides descriptors
 * for both high and full speed operation.  Except in rare cases that don't
 * involve bulk endpoints, each speed needs different endpoint descriptors.
 *
 * Function drivers choose their own strategies for managing instance data.
 * The simplest strategy just declares it "static', which means the function
 * can only be activated once.  If the function needs to be exposed in more
 * than one configuration at a given speed, it needs to support multiple
 * usb_function structures (one for each configuration).
 *
 * A more complex strategy might encapsulate a @usb_function structure inside
 * a driver-specific instance structure to allows multiple activations.  An
 * example of multiple activations might be a CDC ACM function that supports
 * two or more distinct instances within the same configuration, providing
 * several independent logical data links to a USB host.
 */

struct usb_function {
    const char *name;
    struct usb_gadget_strings **strings;
    struct usb_descriptor_header **fs_descriptors;
    struct usb_descriptor_header **hs_descriptors;
    struct usb_descriptor_header **ss_descriptors;
    struct usb_descriptor_header **ssp_descriptors;

    struct usb_configuration *config;

    struct usb_os_desc_table *os_desc_table;
    unsigned os_desc_n;

    /* REVISIT:  bind() functions can be marked __init, which
     * makes trouble for section mismatch analysis.  See if
     * we can't restructure things to avoid mismatching.
     * Related:  unbind() may kfree() but bind() won't...
     */

    /* configuration management:  bind/unbind */
    int (*bind)(struct usb_configuration *, struct usb_function *);
    void (*unbind)(struct usb_configuration *, struct usb_function *);
    void (*free_func)(struct usb_function *f);
    struct module *mod;

    /* runtime state management */
    int (*set_alt)(struct usb_function *, unsigned interface, unsigned alt);
    int (*get_alt)(struct usb_function *, unsigned interface);
    void (*disable)(struct usb_function *);
    int (*setup)(struct usb_function *, const struct usb_ctrlrequest *);
    bool (*req_match)(struct usb_function *, const struct usb_ctrlrequest *, bool config0);
    void (*suspend)(struct usb_function *);
    void (*resume)(struct usb_function *);

    /* USB 3.0 additions */
    int (*get_status)(struct usb_function *);
    int (*func_suspend)(struct usb_function *, u8 suspend_opt);
    /* private: */
    /* internals */
    struct list_head list;
    DECLARE_BITMAP(endpoints, 32);
    const struct usb_function_instance *fi;

    unsigned int bind_deactivated : 1;
};

int usb_add_function(struct usb_configuration *, struct usb_function *);

int usb_function_deactivate(struct usb_function *);
int usb_function_activate(struct usb_function *);

int usb_interface_id(struct usb_configuration *, struct usb_function *);

int config_ep_by_speed_and_alt(struct usb_gadget *g, struct usb_function *f, struct usb_ep *_ep, u8 alt);

int config_ep_by_speed(struct usb_gadget *g, struct usb_function *f, struct usb_ep *_ep);

#define MAX_CONFIG_INTERFACES 16 /* arbitrary; max 255 */

/**
 * struct usb_configuration - represents one gadget configuration
 * @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.
 * @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.
 * @MaxPower: Power consumtion in mA. Used to compute bMaxPower in the
 *    configuration descriptor after considering the bus speed.
 * @cdev: assigned by @usb_add_config() before calling @bind(); this is
 *    the device associated with this configuration.
 *
 * 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 independent 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.
 */
struct usb_configuration {
    const char *label;
    struct usb_gadget_strings **strings;
    const struct usb_descriptor_header **descriptors;

    /* REVISIT:  bind() functions can be marked __init, which
     * makes trouble for section mismatch analysis.  See if
     * we can't restructure things to avoid mismatching...
     */

    /* configuration management: unbind/setup */
    void (*unbind)(struct usb_configuration *);
    int (*setup)(struct usb_configuration *, const struct usb_ctrlrequest *);

    /* fields in the config descriptor */
    u8 bConfigurationValue;
    u8 iConfiguration;
    u8 bmAttributes;
    u16 MaxPower;

    struct usb_composite_dev *cdev;

    /* private: */
    /* internals */
    struct list_head list;
    struct list_head functions;
    u8 next_interface_id;
    unsigned superspeed : 1;
    unsigned highspeed : 1;
    unsigned fullspeed : 1;
    unsigned superspeed_plus : 1;
    struct usb_function *interface[MAX_CONFIG_INTERFACES];
};

int usb_add_config(struct usb_composite_dev *, struct usb_configuration *, int (*)(struct usb_configuration *));

void usb_remove_config(struct usb_composite_dev *, struct usb_configuration *);

/* predefined index for usb_composite_driver */
enum {
    USB_GADGET_MANUFACTURER_IDX = 0,
    USB_GADGET_PRODUCT_IDX,
    USB_GADGET_SERIAL_IDX,
    USB_GADGET_FIRST_AVAIL_IDX,
};

/**
 * struct usb_composite_driver - groups configurations into a gadget
 * @name: For diagnostics, identifies the driver.
 * @dev: Template descriptor for the device, including default device
 *    identifiers.
 * @strings: tables of strings, keyed by identifiers assigned during @bind
 *    and language IDs provided in control requests. Note: The first entries
 *    are predefined. The first entry that may be used is
 *    USB_GADGET_FIRST_AVAIL_IDX
 * @max_speed: Highest speed the driver supports.
 * @needs_serial: set to 1 if the gadget needs userspace to provide
 *     a serial number.  If one is not provided, warning will be printed.
 * @bind: (REQUIRED) Used to allocate resources that are shared across the
 *    whole device, such as string IDs, and add its configurations using
 *    @usb_add_config(). This may fail by returning a negative errno
 *    value; it should return zero on successful initialization.
 * @unbind: Reverses @bind; called as a side effect of unregistering
 *    this driver.
 * @disconnect: optional driver disconnect method
 * @suspend: Notifies when the host stops sending USB traffic,
 *    after function notifications
 * @resume: Notifies configuration when the host restarts USB traffic,
 *    before function notifications
 * @gadget_driver: Gadget driver controlling this driver
 *
 * Devices default to reporting self powered operation.  Devices which rely
 * on bus powered operation should report this in their @bind method.
 *
 * Before returning from @bind, various fields in the template descriptor
 * may be overridden.  These include the idVendor/idProduct/bcdDevice values
 * normally to bind the appropriate host side driver, and the three strings
 * (iManufacturer, iProduct, iSerialNumber) normally used to provide user
 * meaningful device identifiers.  (The strings will not be defined unless
 * they are defined in @dev and @strings.)  The correct ep0 maxpacket size
 * is also reported, as defined by the underlying controller driver.
 */
struct usb_composite_driver {
    const char *name;
    const struct usb_device_descriptor *dev;
    struct usb_gadget_strings **strings;
    enum usb_device_speed max_speed;
    unsigned needs_serial : 1;

    int (*bind)(struct usb_composite_dev *cdev);
    int (*unbind)(struct usb_composite_dev *);

    void (*disconnect)(struct usb_composite_dev *);

    /* global suspend hooks */
    void (*suspend)(struct usb_composite_dev *);
    void (*resume)(struct usb_composite_dev *);
    struct usb_gadget_driver gadget_driver;
};

extern int usb_composite_probe(struct usb_composite_driver *driver);
extern void usb_composite_unregister(struct usb_composite_driver *driver);

/**
 * module_usb_composite_driver() - Helper macro for registering a USB gadget
 * composite driver
 * @__usb_composite_driver: usb_composite_driver struct
 *
 * Helper macro for USB gadget composite drivers which do not do anything
 * special in module init/exit. This eliminates a lot of boilerplate. Each
 * module may only use this macro once, and calling it replaces module_init()
 * and module_exit()
 */
#define module_usb_composite_driver(__usb_composite_driver)                                                            \
    module_driver(__usb_composite_driver, usb_composite_probe, usb_composite_unregister)

extern void usb_composite_setup_continue(struct usb_composite_dev *cdev);
extern int composite_dev_prepare(struct usb_composite_driver *composite, struct usb_composite_dev *cdev);
extern int composite_os_desc_req_prepare(struct usb_composite_dev *cdev, struct usb_ep *ep0);
void composite_dev_cleanup(struct usb_composite_dev *cdev);

static inline struct usb_composite_driver *to_cdriver(struct usb_gadget_driver *gdrv)
{
    return container_of(gdrv, struct usb_composite_driver, gadget_driver);
}

#define OS_STRING_QW_SIGN_LEN 14
#define OS_STRING_IDX 0xEE

/**
 * struct usb_composite_dev - represents one composite usb gadget
 * @gadget: read-only, abstracts the gadget's usb peripheral controller
 * @req: used for control responses; buffer is pre-allocated
 * @os_desc_req: used for OS descriptors responses; buffer is pre-allocated
 * @config: the currently active configuration
 * @qw_sign: qwSignature part of the OS string
 * @b_vendor_code: bMS_VendorCode part of the OS string
 * @use_os_string: false by default, interested gadgets set it
 * @os_desc_config: the configuration to be used with OS descriptors
 * @setup_pending: true when setup request is queued but not completed
 * @os_desc_pending: true when os_desc request is queued but not completed
 *
 * One of these devices is allocated and initialized before the
 * associated device driver's bind() is called.
 *
 * OPEN ISSUE:  it appears that some WUSB devices will need to be
 * built by combining a normal (wired) gadget with a wireless one.
 * This revision of the gadget framework should probably try to make
 * sure doing that won't hurt too much.
 *
 * One notion for how to handle Wireless USB devices involves:
 *
 * (a) a second gadget here, discovery mechanism, but likely
 *     needing separate "register/unregister WUSB gadget" calls;
 * (b) updates to usb_gadget to include flags "is it wireless",
 *     "is it wired", plus (presumably in a wrapper structure)
 *     bandgroup and PHY info;
 * (c) presumably a wireless_ep wrapping a usb_ep, and reporting
 *     wireless-specific parameters like maxburst and maxsequence;
 * (d) configurations that are specific to wireless links;
 * (e) function drivers that understand wireless configs and will
 *     support wireless for (additional) function instances;
 * (f) a function to support association setup (like CBAF), not
 *     necessarily requiring a wireless adapter;
 * (g) composite device setup that can create one or more wireless
 *     configs, including appropriate association setup support;
 * (h) more.
 */
struct usb_composite_dev {
    struct usb_gadget *gadget;
    struct usb_request *req;
    struct usb_request *os_desc_req;

    struct usb_configuration *config;

    /* OS String is a custom (yet popular) extension to the USB standard. */
    u8 qw_sign[OS_STRING_QW_SIGN_LEN];
    u8 b_vendor_code;
    struct usb_configuration *os_desc_config;
    unsigned int use_os_string : 1;

    /* private: */
    /* internals */
    unsigned int suspended : 1;
    struct usb_device_descriptor desc;
    struct list_head configs;
    struct list_head gstrings;
    struct usb_composite_driver *driver;
    u8 next_string_id;
    char *def_manufacturer;

    /* the gadget driver won't enable the data pullup
     * while the deactivation count is nonzero.
     */
    unsigned deactivations;

    /* the composite driver won't complete the control transfer's
     * data/status stages till delayed_status is zero.
     */
    int delayed_status;

    /* protects deactivations and delayed_status counts */
    spinlock_t lock;

    /* public: */
    unsigned int setup_pending : 1;
    unsigned int os_desc_pending : 1;
};

extern int usb_string_id(struct usb_composite_dev *c);
extern int usb_string_ids_tab(struct usb_composite_dev *c, struct usb_string *str);
extern struct usb_string *usb_gstrings_attach(struct usb_composite_dev *cdev, struct usb_gadget_strings **sp,
                                              unsigned n_strings);

extern int usb_string_ids_n(struct usb_composite_dev *c, unsigned n);

extern void composite_disconnect(struct usb_gadget *gadget);
extern void composite_reset(struct usb_gadget *gadget);

extern int composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl);
extern void composite_suspend(struct usb_gadget *gadget);
extern void composite_resume(struct usb_gadget *gadget);

/*
 * Some systems will need runtime overrides for the  product identifiers
 * published in the device descriptor, either numbers or strings or both.
 * String parameters are in UTF-8 (superset of ASCII's 7 bit characters).
 */
struct usb_composite_overwrite {
    u16 idVendor;
    u16 idProduct;
    u16 bcdDevice;
    char *serial_number;
    char *manufacturer;
    char *product;
};
#define USB_GADGET_COMPOSITE_OPTIONS()                                                                                 \
    static struct usb_composite_overwrite coverwrite;                                                                  \
                                                                                                                       \
    module_param_named(idVendor, coverwrite.idVendor, ushort, S_IRUGO);                                                \
    MODULE_PARM_DESC(idVendor, "USB Vendor ID");                                                                       \
                                                                                                                       \
    module_param_named(idProduct, coverwrite.idProduct, ushort, S_IRUGO);                                              \
    MODULE_PARM_DESC(idProduct, "USB Product ID");                                                                     \
                                                                                                                       \
    module_param_named(bcdDevice, coverwrite.bcdDevice, ushort, S_IRUGO);                                              \
    MODULE_PARM_DESC(bcdDevice, "USB Device version (BCD)");                                                           \
                                                                                                                       \
    module_param_named(iSerialNumber, coverwrite.serial_number, charp, S_IRUGO);                                       \
    MODULE_PARM_DESC(iSerialNumber, "SerialNumber string");                                                            \
                                                                                                                       \
    module_param_named(iManufacturer, coverwrite.manufacturer, charp, S_IRUGO);                                        \
    MODULE_PARM_DESC(iManufacturer, "USB Manufacturer string");                                                        \
                                                                                                                       \
    module_param_named(iProduct, coverwrite.product, charp, S_IRUGO);                                                  \
    MODULE_PARM_DESC(iProduct, "USB Product string")

void usb_composite_overwrite_options(struct usb_composite_dev *cdev, struct usb_composite_overwrite *covr);

static inline u16 get_default_bcdDevice(void)
{
    u16 bcdDevice;

    bcdDevice = bin2bcd(((LINUX_VERSION_CODE >> 0x10) & 0xff)) << 0x8;
    bcdDevice |= bin2bcd(((LINUX_VERSION_CODE >> 0x8) & 0xff));
    return bcdDevice;
}

struct usb_function_driver {
    const char *name;
    struct module *mod;
    struct list_head list;
    struct usb_function_instance *(*alloc_inst)(void);
    struct usb_function *(*alloc_func)(struct usb_function_instance *inst);
};

struct usb_function_instance {
    struct config_group group;
    struct list_head cfs_list;
    struct usb_function_driver *fd;
    struct usb_function *f;
    int (*set_inst_name)(struct usb_function_instance *inst, const char *name);
    void (*free_func_inst)(struct usb_function_instance *inst);
};

void usb_function_unregister(struct usb_function_driver *f);
int usb_function_register(struct usb_function_driver *newf);
void usb_put_function_instance(struct usb_function_instance *fi);
void usb_put_function(struct usb_function *f);
struct usb_function_instance *usb_get_function_instance(const char *name);
struct usb_function *usb_get_function(struct usb_function_instance *fi);

struct usb_configuration *usb_get_config(struct usb_composite_dev *cdev, int val);
int usb_add_config_only(struct usb_composite_dev *cdev, struct usb_configuration *config);
void usb_remove_function(struct usb_configuration *c, struct usb_function *f);

#define DECLARE_USB_FUNCTION(_name, _inst_alloc, _func_alloc)                                                          \
    static struct usb_function_driver _name##usb_func = {                                                              \
        .name = __stringify(_name),                                                                                    \
        .mod = THIS_MODULE,                                                                                            \
        .alloc_inst = (_inst_alloc),                                                                                   \
        .alloc_func = (_func_alloc),                                                                                   \
    };                                                                                                                 \
    MODULE_ALIAS("usbfunc:"__stringify(_name));

#define DECLARE_USB_FUNCTION_INIT(_name, _inst_alloc, _func_alloc)                                                     \
    DECLARE_USB_FUNCTION(_name, _inst_alloc, _func_alloc)                                                              \
    static int __init _name##mod_init(void)                                                                            \
    {                                                                                                                  \
        return usb_function_register(&_name##usb_func);                                                                \
    }                                                                                                                  \
    static void __exit _name##mod_exit(void)                                                                           \
    {                                                                                                                  \
        usb_function_unregister(&_name##usb_func);                                                                     \
    }                                                                                                                  \
    module_init(_name##mod_init);                                                                                      \
    module_exit(_name##mod_exit)

/* messaging utils */
#define DBG(d, fmt, args...) dev_dbg(&(d)->gadget->dev, fmt, ##args)
#define VDBG(d, fmt, args...) dev_vdbg(&(d)->gadget->dev, fmt, ##args)
#define ERROR(d, fmt, args...) dev_err(&(d)->gadget->dev, fmt, ##args)
#define WARNING(d, fmt, args...) dev_warn(&(d)->gadget->dev, fmt, ##args)
#define INFO(d, fmt, args...) dev_info(&(d)->gadget->dev, fmt, ##args)

#endif /* __LINUX_USB_COMPOSITE_H */