xref: /linux-6.15/include/linux/usb/composite.h (revision bbb03029)
1 /*
2  * composite.h -- framework for usb gadgets which are composite devices
3  *
4  * Copyright (C) 2006-2008 David Brownell
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
19  */
20 
21 #ifndef	__LINUX_USB_COMPOSITE_H
22 #define	__LINUX_USB_COMPOSITE_H
23 
24 /*
25  * This framework is an optional layer on top of the USB Gadget interface,
26  * making it easier to build (a) Composite devices, supporting multiple
27  * functions within any single configuration, and (b) Multi-configuration
28  * devices, also supporting multiple functions but without necessarily
29  * having more than one function per configuration.
30  *
31  * Example:  a device with a single configuration supporting both network
32  * link and mass storage functions is a composite device.  Those functions
33  * might alternatively be packaged in individual configurations, but in
34  * the composite model the host can use both functions at the same time.
35  */
36 
37 #include <linux/bcd.h>
38 #include <linux/version.h>
39 #include <linux/usb/ch9.h>
40 #include <linux/usb/gadget.h>
41 #include <linux/log2.h>
42 #include <linux/configfs.h>
43 
44 /*
45  * USB function drivers should return USB_GADGET_DELAYED_STATUS if they
46  * wish to delay the data/status stages of the control transfer till they
47  * are ready. The control transfer will then be kept from completing till
48  * all the function drivers that requested for USB_GADGET_DELAYED_STAUS
49  * invoke usb_composite_setup_continue().
50  */
51 #define USB_GADGET_DELAYED_STATUS       0x7fff	/* Impossibly large value */
52 
53 /* big enough to hold our biggest descriptor */
54 #define USB_COMP_EP0_BUFSIZ	1024
55 
56 #define USB_MS_TO_HS_INTERVAL(x)	(ilog2((x * 1000 / 125)) + 1)
57 struct usb_configuration;
58 
59 /**
60  * struct usb_os_desc_ext_prop - describes one "Extended Property"
61  * @entry: used to keep a list of extended properties
62  * @type: Extended Property type
63  * @name_len: Extended Property unicode name length, including terminating '\0'
64  * @name: Extended Property name
65  * @data_len: Length of Extended Property blob (for unicode store double len)
66  * @data: Extended Property blob
67  * @item: Represents this Extended Property in configfs
68  */
69 struct usb_os_desc_ext_prop {
70 	struct list_head	entry;
71 	u8			type;
72 	int			name_len;
73 	char			*name;
74 	int			data_len;
75 	char			*data;
76 	struct config_item	item;
77 };
78 
79 /**
80  * struct usb_os_desc - describes OS descriptors associated with one interface
81  * @ext_compat_id: 16 bytes of "Compatible ID" and "Subcompatible ID"
82  * @ext_prop: Extended Properties list
83  * @ext_prop_len: Total length of Extended Properties blobs
84  * @ext_prop_count: Number of Extended Properties
85  * @opts_mutex: Optional mutex protecting config data of a usb_function_instance
86  * @group: Represents OS descriptors associated with an interface in configfs
87  * @owner: Module associated with this OS descriptor
88  */
89 struct usb_os_desc {
90 	char			*ext_compat_id;
91 	struct list_head	ext_prop;
92 	int			ext_prop_len;
93 	int			ext_prop_count;
94 	struct mutex		*opts_mutex;
95 	struct config_group	group;
96 	struct module		*owner;
97 };
98 
99 /**
100  * struct usb_os_desc_table - describes OS descriptors associated with one
101  * interface of a usb_function
102  * @if_id: Interface id
103  * @os_desc: "Extended Compatibility ID" and "Extended Properties" of the
104  *	interface
105  *
106  * Each interface can have at most one "Extended Compatibility ID" and a
107  * number of "Extended Properties".
108  */
109 struct usb_os_desc_table {
110 	int			if_id;
111 	struct usb_os_desc	*os_desc;
112 };
113 
114 /**
115  * struct usb_function - describes one function of a configuration
116  * @name: For diagnostics, identifies the function.
117  * @strings: tables of strings, keyed by identifiers assigned during bind()
118  *	and by language IDs provided in control requests
119  * @fs_descriptors: Table of full (or low) speed descriptors, using interface and
120  *	string identifiers assigned during @bind().  If this pointer is null,
121  *	the function will not be available at full speed (or at low speed).
122  * @hs_descriptors: Table of high speed descriptors, using interface and
123  *	string identifiers assigned during @bind().  If this pointer is null,
124  *	the function will not be available at high speed.
125  * @ss_descriptors: Table of super speed descriptors, using interface and
126  *	string identifiers assigned during @bind(). If this
127  *	pointer is null after initiation, the function will not
128  *	be available at super speed.
129  * @ssp_descriptors: Table of super speed plus descriptors, using
130  *	interface and string identifiers assigned during @bind(). If
131  *	this pointer is null after initiation, the function will not
132  *	be available at super speed plus.
133  * @config: assigned when @usb_add_function() is called; this is the
134  *	configuration with which this function is associated.
135  * @os_desc_table: Table of (interface id, os descriptors) pairs. The function
136  *	can expose more than one interface. If an interface is a member of
137  *	an IAD, only the first interface of IAD has its entry in the table.
138  * @os_desc_n: Number of entries in os_desc_table
139  * @bind: Before the gadget can register, all of its functions bind() to the
140  *	available resources including string and interface identifiers used
141  *	in interface or class descriptors; endpoints; I/O buffers; and so on.
142  * @unbind: Reverses @bind; called as a side effect of unregistering the
143  *	driver which added this function.
144  * @free_func: free the struct usb_function.
145  * @mod: (internal) points to the module that created this structure.
146  * @set_alt: (REQUIRED) Reconfigures altsettings; function drivers may
147  *	initialize usb_ep.driver data at this time (when it is used).
148  *	Note that setting an interface to its current altsetting resets
149  *	interface state, and that all interfaces have a disabled state.
150  * @get_alt: Returns the active altsetting.  If this is not provided,
151  *	then only altsetting zero is supported.
152  * @disable: (REQUIRED) Indicates the function should be disabled.  Reasons
153  *	include host resetting or reconfiguring the gadget, and disconnection.
154  * @setup: Used for interface-specific control requests.
155  * @req_match: Tests if a given class request can be handled by this function.
156  * @suspend: Notifies functions when the host stops sending USB traffic.
157  * @resume: Notifies functions when the host restarts USB traffic.
158  * @get_status: Returns function status as a reply to
159  *	GetStatus() request when the recipient is Interface.
160  * @func_suspend: callback to be called when
161  *	SetFeature(FUNCTION_SUSPEND) is reseived
162  *
163  * A single USB function uses one or more interfaces, and should in most
164  * cases support operation at both full and high speeds.  Each function is
165  * associated by @usb_add_function() with a one configuration; that function
166  * causes @bind() to be called so resources can be allocated as part of
167  * setting up a gadget driver.  Those resources include endpoints, which
168  * should be allocated using @usb_ep_autoconfig().
169  *
170  * To support dual speed operation, a function driver provides descriptors
171  * for both high and full speed operation.  Except in rare cases that don't
172  * involve bulk endpoints, each speed needs different endpoint descriptors.
173  *
174  * Function drivers choose their own strategies for managing instance data.
175  * The simplest strategy just declares it "static', which means the function
176  * can only be activated once.  If the function needs to be exposed in more
177  * than one configuration at a given speed, it needs to support multiple
178  * usb_function structures (one for each configuration).
179  *
180  * A more complex strategy might encapsulate a @usb_function structure inside
181  * a driver-specific instance structure to allows multiple activations.  An
182  * example of multiple activations might be a CDC ACM function that supports
183  * two or more distinct instances within the same configuration, providing
184  * several independent logical data links to a USB host.
185  */
186 
187 struct usb_function {
188 	const char			*name;
189 	struct usb_gadget_strings	**strings;
190 	struct usb_descriptor_header	**fs_descriptors;
191 	struct usb_descriptor_header	**hs_descriptors;
192 	struct usb_descriptor_header	**ss_descriptors;
193 	struct usb_descriptor_header	**ssp_descriptors;
194 
195 	struct usb_configuration	*config;
196 
197 	struct usb_os_desc_table	*os_desc_table;
198 	unsigned			os_desc_n;
199 
200 	/* REVISIT:  bind() functions can be marked __init, which
201 	 * makes trouble for section mismatch analysis.  See if
202 	 * we can't restructure things to avoid mismatching.
203 	 * Related:  unbind() may kfree() but bind() won't...
204 	 */
205 
206 	/* configuration management:  bind/unbind */
207 	int			(*bind)(struct usb_configuration *,
208 					struct usb_function *);
209 	void			(*unbind)(struct usb_configuration *,
210 					struct usb_function *);
211 	void			(*free_func)(struct usb_function *f);
212 	struct module		*mod;
213 
214 	/* runtime state management */
215 	int			(*set_alt)(struct usb_function *,
216 					unsigned interface, unsigned alt);
217 	int			(*get_alt)(struct usb_function *,
218 					unsigned interface);
219 	void			(*disable)(struct usb_function *);
220 	int			(*setup)(struct usb_function *,
221 					const struct usb_ctrlrequest *);
222 	bool			(*req_match)(struct usb_function *,
223 					const struct usb_ctrlrequest *,
224 					bool config0);
225 	void			(*suspend)(struct usb_function *);
226 	void			(*resume)(struct usb_function *);
227 
228 	/* USB 3.0 additions */
229 	int			(*get_status)(struct usb_function *);
230 	int			(*func_suspend)(struct usb_function *,
231 						u8 suspend_opt);
232 	/* private: */
233 	/* internals */
234 	struct list_head		list;
235 	DECLARE_BITMAP(endpoints, 32);
236 	const struct usb_function_instance *fi;
237 
238 	unsigned int		bind_deactivated:1;
239 };
240 
241 int usb_add_function(struct usb_configuration *, struct usb_function *);
242 
243 int usb_function_deactivate(struct usb_function *);
244 int usb_function_activate(struct usb_function *);
245 
246 int usb_interface_id(struct usb_configuration *, struct usb_function *);
247 
248 int config_ep_by_speed(struct usb_gadget *g, struct usb_function *f,
249 			struct usb_ep *_ep);
250 
251 #define	MAX_CONFIG_INTERFACES		16	/* arbitrary; max 255 */
252 
253 /**
254  * struct usb_configuration - represents one gadget configuration
255  * @label: For diagnostics, describes the configuration.
256  * @strings: Tables of strings, keyed by identifiers assigned during @bind()
257  *	and by language IDs provided in control requests.
258  * @descriptors: Table of descriptors preceding all function descriptors.
259  *	Examples include OTG and vendor-specific descriptors.
260  * @unbind: Reverses @bind; called as a side effect of unregistering the
261  *	driver which added this configuration.
262  * @setup: Used to delegate control requests that aren't handled by standard
263  *	device infrastructure or directed at a specific interface.
264  * @bConfigurationValue: Copied into configuration descriptor.
265  * @iConfiguration: Copied into configuration descriptor.
266  * @bmAttributes: Copied into configuration descriptor.
267  * @MaxPower: Power consumtion in mA. Used to compute bMaxPower in the
268  *	configuration descriptor after considering the bus speed.
269  * @cdev: assigned by @usb_add_config() before calling @bind(); this is
270  *	the device associated with this configuration.
271  *
272  * Configurations are building blocks for gadget drivers structured around
273  * function drivers.  Simple USB gadgets require only one function and one
274  * configuration, and handle dual-speed hardware by always providing the same
275  * functionality.  Slightly more complex gadgets may have more than one
276  * single-function configuration at a given speed; or have configurations
277  * that only work at one speed.
278  *
279  * Composite devices are, by definition, ones with configurations which
280  * include more than one function.
281  *
282  * The lifecycle of a usb_configuration includes allocation, initialization
283  * of the fields described above, and calling @usb_add_config() to set up
284  * internal data and bind it to a specific device.  The configuration's
285  * @bind() method is then used to initialize all the functions and then
286  * call @usb_add_function() for them.
287  *
288  * Those functions would normally be independent of each other, but that's
289  * not mandatory.  CDC WMC devices are an example where functions often
290  * depend on other functions, with some functions subsidiary to others.
291  * Such interdependency may be managed in any way, so long as all of the
292  * descriptors complete by the time the composite driver returns from
293  * its bind() routine.
294  */
295 struct usb_configuration {
296 	const char			*label;
297 	struct usb_gadget_strings	**strings;
298 	const struct usb_descriptor_header **descriptors;
299 
300 	/* REVISIT:  bind() functions can be marked __init, which
301 	 * makes trouble for section mismatch analysis.  See if
302 	 * we can't restructure things to avoid mismatching...
303 	 */
304 
305 	/* configuration management: unbind/setup */
306 	void			(*unbind)(struct usb_configuration *);
307 	int			(*setup)(struct usb_configuration *,
308 					const struct usb_ctrlrequest *);
309 
310 	/* fields in the config descriptor */
311 	u8			bConfigurationValue;
312 	u8			iConfiguration;
313 	u8			bmAttributes;
314 	u16			MaxPower;
315 
316 	struct usb_composite_dev	*cdev;
317 
318 	/* private: */
319 	/* internals */
320 	struct list_head	list;
321 	struct list_head	functions;
322 	u8			next_interface_id;
323 	unsigned		superspeed:1;
324 	unsigned		highspeed:1;
325 	unsigned		fullspeed:1;
326 	unsigned		superspeed_plus:1;
327 	struct usb_function	*interface[MAX_CONFIG_INTERFACES];
328 };
329 
330 int usb_add_config(struct usb_composite_dev *,
331 		struct usb_configuration *,
332 		int (*)(struct usb_configuration *));
333 
334 void usb_remove_config(struct usb_composite_dev *,
335 		struct usb_configuration *);
336 
337 /* predefined index for usb_composite_driver */
338 enum {
339 	USB_GADGET_MANUFACTURER_IDX	= 0,
340 	USB_GADGET_PRODUCT_IDX,
341 	USB_GADGET_SERIAL_IDX,
342 	USB_GADGET_FIRST_AVAIL_IDX,
343 };
344 
345 /**
346  * struct usb_composite_driver - groups configurations into a gadget
347  * @name: For diagnostics, identifies the driver.
348  * @dev: Template descriptor for the device, including default device
349  *	identifiers.
350  * @strings: tables of strings, keyed by identifiers assigned during @bind
351  *	and language IDs provided in control requests. Note: The first entries
352  *	are predefined. The first entry that may be used is
353  *	USB_GADGET_FIRST_AVAIL_IDX
354  * @max_speed: Highest speed the driver supports.
355  * @needs_serial: set to 1 if the gadget needs userspace to provide
356  * 	a serial number.  If one is not provided, warning will be printed.
357  * @bind: (REQUIRED) Used to allocate resources that are shared across the
358  *	whole device, such as string IDs, and add its configurations using
359  *	@usb_add_config(). This may fail by returning a negative errno
360  *	value; it should return zero on successful initialization.
361  * @unbind: Reverses @bind; called as a side effect of unregistering
362  *	this driver.
363  * @disconnect: optional driver disconnect method
364  * @suspend: Notifies when the host stops sending USB traffic,
365  *	after function notifications
366  * @resume: Notifies configuration when the host restarts USB traffic,
367  *	before function notifications
368  * @gadget_driver: Gadget driver controlling this driver
369  *
370  * Devices default to reporting self powered operation.  Devices which rely
371  * on bus powered operation should report this in their @bind method.
372  *
373  * Before returning from @bind, various fields in the template descriptor
374  * may be overridden.  These include the idVendor/idProduct/bcdDevice values
375  * normally to bind the appropriate host side driver, and the three strings
376  * (iManufacturer, iProduct, iSerialNumber) normally used to provide user
377  * meaningful device identifiers.  (The strings will not be defined unless
378  * they are defined in @dev and @strings.)  The correct ep0 maxpacket size
379  * is also reported, as defined by the underlying controller driver.
380  */
381 struct usb_composite_driver {
382 	const char				*name;
383 	const struct usb_device_descriptor	*dev;
384 	struct usb_gadget_strings		**strings;
385 	enum usb_device_speed			max_speed;
386 	unsigned		needs_serial:1;
387 
388 	int			(*bind)(struct usb_composite_dev *cdev);
389 	int			(*unbind)(struct usb_composite_dev *);
390 
391 	void			(*disconnect)(struct usb_composite_dev *);
392 
393 	/* global suspend hooks */
394 	void			(*suspend)(struct usb_composite_dev *);
395 	void			(*resume)(struct usb_composite_dev *);
396 	struct usb_gadget_driver		gadget_driver;
397 };
398 
399 extern int usb_composite_probe(struct usb_composite_driver *driver);
400 extern void usb_composite_unregister(struct usb_composite_driver *driver);
401 
402 /**
403  * module_usb_composite_driver() - Helper macro for registering a USB gadget
404  * composite driver
405  * @__usb_composite_driver: usb_composite_driver struct
406  *
407  * Helper macro for USB gadget composite drivers which do not do anything
408  * special in module init/exit. This eliminates a lot of boilerplate. Each
409  * module may only use this macro once, and calling it replaces module_init()
410  * and module_exit()
411  */
412 #define module_usb_composite_driver(__usb_composite_driver) \
413 	module_driver(__usb_composite_driver, usb_composite_probe, \
414 		       usb_composite_unregister)
415 
416 extern void usb_composite_setup_continue(struct usb_composite_dev *cdev);
417 extern int composite_dev_prepare(struct usb_composite_driver *composite,
418 		struct usb_composite_dev *cdev);
419 extern int composite_os_desc_req_prepare(struct usb_composite_dev *cdev,
420 					 struct usb_ep *ep0);
421 void composite_dev_cleanup(struct usb_composite_dev *cdev);
422 
423 static inline struct usb_composite_driver *to_cdriver(
424 		struct usb_gadget_driver *gdrv)
425 {
426 	return container_of(gdrv, struct usb_composite_driver, gadget_driver);
427 }
428 
429 #define OS_STRING_QW_SIGN_LEN		14
430 #define OS_STRING_IDX			0xEE
431 
432 /**
433  * struct usb_composite_device - represents one composite usb gadget
434  * @gadget: read-only, abstracts the gadget's usb peripheral controller
435  * @req: used for control responses; buffer is pre-allocated
436  * @os_desc_req: used for OS descriptors responses; buffer is pre-allocated
437  * @config: the currently active configuration
438  * @qw_sign: qwSignature part of the OS string
439  * @b_vendor_code: bMS_VendorCode part of the OS string
440  * @use_os_string: false by default, interested gadgets set it
441  * @os_desc_config: the configuration to be used with OS descriptors
442  * @setup_pending: true when setup request is queued but not completed
443  * @os_desc_pending: true when os_desc request is queued but not completed
444  *
445  * One of these devices is allocated and initialized before the
446  * associated device driver's bind() is called.
447  *
448  * OPEN ISSUE:  it appears that some WUSB devices will need to be
449  * built by combining a normal (wired) gadget with a wireless one.
450  * This revision of the gadget framework should probably try to make
451  * sure doing that won't hurt too much.
452  *
453  * One notion for how to handle Wireless USB devices involves:
454  *
455  * (a) a second gadget here, discovery mechanism TBD, but likely
456  *     needing separate "register/unregister WUSB gadget" calls;
457  * (b) updates to usb_gadget to include flags "is it wireless",
458  *     "is it wired", plus (presumably in a wrapper structure)
459  *     bandgroup and PHY info;
460  * (c) presumably a wireless_ep wrapping a usb_ep, and reporting
461  *     wireless-specific parameters like maxburst and maxsequence;
462  * (d) configurations that are specific to wireless links;
463  * (e) function drivers that understand wireless configs and will
464  *     support wireless for (additional) function instances;
465  * (f) a function to support association setup (like CBAF), not
466  *     necessarily requiring a wireless adapter;
467  * (g) composite device setup that can create one or more wireless
468  *     configs, including appropriate association setup support;
469  * (h) more, TBD.
470  */
471 struct usb_composite_dev {
472 	struct usb_gadget		*gadget;
473 	struct usb_request		*req;
474 	struct usb_request		*os_desc_req;
475 
476 	struct usb_configuration	*config;
477 
478 	/* OS String is a custom (yet popular) extension to the USB standard. */
479 	u8				qw_sign[OS_STRING_QW_SIGN_LEN];
480 	u8				b_vendor_code;
481 	struct usb_configuration	*os_desc_config;
482 	unsigned int			use_os_string:1;
483 
484 	/* private: */
485 	/* internals */
486 	unsigned int			suspended:1;
487 	struct usb_device_descriptor	desc;
488 	struct list_head		configs;
489 	struct list_head		gstrings;
490 	struct usb_composite_driver	*driver;
491 	u8				next_string_id;
492 	char				*def_manufacturer;
493 
494 	/* the gadget driver won't enable the data pullup
495 	 * while the deactivation count is nonzero.
496 	 */
497 	unsigned			deactivations;
498 
499 	/* the composite driver won't complete the control transfer's
500 	 * data/status stages till delayed_status is zero.
501 	 */
502 	int				delayed_status;
503 
504 	/* protects deactivations and delayed_status counts*/
505 	spinlock_t			lock;
506 
507 	/* public: */
508 	unsigned int			setup_pending:1;
509 	unsigned int			os_desc_pending:1;
510 };
511 
512 extern int usb_string_id(struct usb_composite_dev *c);
513 extern int usb_string_ids_tab(struct usb_composite_dev *c,
514 			      struct usb_string *str);
515 extern struct usb_string *usb_gstrings_attach(struct usb_composite_dev *cdev,
516 		struct usb_gadget_strings **sp, unsigned n_strings);
517 
518 extern int usb_string_ids_n(struct usb_composite_dev *c, unsigned n);
519 
520 extern void composite_disconnect(struct usb_gadget *gadget);
521 extern int composite_setup(struct usb_gadget *gadget,
522 		const struct usb_ctrlrequest *ctrl);
523 extern void composite_suspend(struct usb_gadget *gadget);
524 extern void composite_resume(struct usb_gadget *gadget);
525 
526 /*
527  * Some systems will need runtime overrides for the  product identifiers
528  * published in the device descriptor, either numbers or strings or both.
529  * String parameters are in UTF-8 (superset of ASCII's 7 bit characters).
530  */
531 struct usb_composite_overwrite {
532 	u16	idVendor;
533 	u16	idProduct;
534 	u16	bcdDevice;
535 	char	*serial_number;
536 	char	*manufacturer;
537 	char	*product;
538 };
539 #define USB_GADGET_COMPOSITE_OPTIONS()					\
540 	static struct usb_composite_overwrite coverwrite;		\
541 									\
542 	module_param_named(idVendor, coverwrite.idVendor, ushort, S_IRUGO); \
543 	MODULE_PARM_DESC(idVendor, "USB Vendor ID");			\
544 									\
545 	module_param_named(idProduct, coverwrite.idProduct, ushort, S_IRUGO); \
546 	MODULE_PARM_DESC(idProduct, "USB Product ID");			\
547 									\
548 	module_param_named(bcdDevice, coverwrite.bcdDevice, ushort, S_IRUGO); \
549 	MODULE_PARM_DESC(bcdDevice, "USB Device version (BCD)");	\
550 									\
551 	module_param_named(iSerialNumber, coverwrite.serial_number, charp, \
552 			S_IRUGO); \
553 	MODULE_PARM_DESC(iSerialNumber, "SerialNumber string");		\
554 									\
555 	module_param_named(iManufacturer, coverwrite.manufacturer, charp, \
556 			S_IRUGO); \
557 	MODULE_PARM_DESC(iManufacturer, "USB Manufacturer string");	\
558 									\
559 	module_param_named(iProduct, coverwrite.product, charp, S_IRUGO); \
560 	MODULE_PARM_DESC(iProduct, "USB Product string")
561 
562 void usb_composite_overwrite_options(struct usb_composite_dev *cdev,
563 		struct usb_composite_overwrite *covr);
564 
565 static inline u16 get_default_bcdDevice(void)
566 {
567 	u16 bcdDevice;
568 
569 	bcdDevice = bin2bcd((LINUX_VERSION_CODE >> 16 & 0xff)) << 8;
570 	bcdDevice |= bin2bcd((LINUX_VERSION_CODE >> 8 & 0xff));
571 	return bcdDevice;
572 }
573 
574 struct usb_function_driver {
575 	const char *name;
576 	struct module *mod;
577 	struct list_head list;
578 	struct usb_function_instance *(*alloc_inst)(void);
579 	struct usb_function *(*alloc_func)(struct usb_function_instance *inst);
580 };
581 
582 struct usb_function_instance {
583 	struct config_group group;
584 	struct list_head cfs_list;
585 	struct usb_function_driver *fd;
586 	int (*set_inst_name)(struct usb_function_instance *inst,
587 			      const char *name);
588 	void (*free_func_inst)(struct usb_function_instance *inst);
589 };
590 
591 void usb_function_unregister(struct usb_function_driver *f);
592 int usb_function_register(struct usb_function_driver *newf);
593 void usb_put_function_instance(struct usb_function_instance *fi);
594 void usb_put_function(struct usb_function *f);
595 struct usb_function_instance *usb_get_function_instance(const char *name);
596 struct usb_function *usb_get_function(struct usb_function_instance *fi);
597 
598 struct usb_configuration *usb_get_config(struct usb_composite_dev *cdev,
599 		int val);
600 int usb_add_config_only(struct usb_composite_dev *cdev,
601 		struct usb_configuration *config);
602 void usb_remove_function(struct usb_configuration *c, struct usb_function *f);
603 
604 #define DECLARE_USB_FUNCTION(_name, _inst_alloc, _func_alloc)		\
605 	static struct usb_function_driver _name ## usb_func = {		\
606 		.name = __stringify(_name),				\
607 		.mod  = THIS_MODULE,					\
608 		.alloc_inst = _inst_alloc,				\
609 		.alloc_func = _func_alloc,				\
610 	};								\
611 	MODULE_ALIAS("usbfunc:"__stringify(_name));
612 
613 #define DECLARE_USB_FUNCTION_INIT(_name, _inst_alloc, _func_alloc)	\
614 	DECLARE_USB_FUNCTION(_name, _inst_alloc, _func_alloc)		\
615 	static int __init _name ## mod_init(void)			\
616 	{								\
617 		return usb_function_register(&_name ## usb_func);	\
618 	}								\
619 	static void __exit _name ## mod_exit(void)			\
620 	{								\
621 		usb_function_unregister(&_name ## usb_func);		\
622 	}								\
623 	module_init(_name ## mod_init);					\
624 	module_exit(_name ## mod_exit)
625 
626 /* messaging utils */
627 #define DBG(d, fmt, args...) \
628 	dev_dbg(&(d)->gadget->dev , fmt , ## args)
629 #define VDBG(d, fmt, args...) \
630 	dev_vdbg(&(d)->gadget->dev , fmt , ## args)
631 #define ERROR(d, fmt, args...) \
632 	dev_err(&(d)->gadget->dev , fmt , ## args)
633 #define WARNING(d, fmt, args...) \
634 	dev_warn(&(d)->gadget->dev , fmt , ## args)
635 #define INFO(d, fmt, args...) \
636 	dev_info(&(d)->gadget->dev , fmt , ## args)
637 
638 #endif	/* __LINUX_USB_COMPOSITE_H */
639