usb: gadget: uvc: configfs support in uvc function

Add support for using the uvc function as a component of USB gadgets composed
with configfs.
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Documentation/ABI/testing/configfs-usb-gadget-uvc

+What:		/config/usb-gadget/gadget/functions/uvc.name
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	UVC function directory
+
+		streaming_maxburst	- 0..15 (ss only)
+		streaming_maxpacket	- 1..1023 (fs), 1..3072 (hs/ss)
+		streaming_interval	- 1..16
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/control
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Control descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/control/class
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Class descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/control/class/ss
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Super speed control class descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/control/class/fs
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Full speed control class descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/control/terminal
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Terminal descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/control/terminal/output
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Output terminal descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/control/terminal/output/default
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Default output terminal descriptors
+
+		All attributes read only:
+		iTerminal	- index of string descriptor
+		bSourceID 	- id of the terminal to which this terminal
+				is connected
+		bAssocTerminal	- id of the input terminal to which this output
+				terminal is associated
+		wTerminalType	- terminal type
+		bTerminalID	- a non-zero id of this terminal
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/control/terminal/camera
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Camera terminal descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/control/terminal/camera/default
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Default camera terminal descriptors
+
+		All attributes read only:
+		bmControls		- bitmap specifying which controls are
+					supported for the video stream
+		wOcularFocalLength	- the value of Locular
+		wObjectiveFocalLengthMax- the value of Lmin
+		wObjectiveFocalLengthMin- the value of Lmax
+		iTerminal		- index of string descriptor
+		bAssocTerminal		- id of the output terminal to which
+					this terminal is connected
+		wTerminalType		- terminal type
+		bTerminalID		- a non-zero id of this terminal
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/control/processing
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Processing unit descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/control/processing/default
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Default processing unit descriptors
+
+		All attributes read only:
+		iProcessing	- index of string descriptor
+		bmControls	- bitmap specifying which controls are
+				supported for the video stream
+		wMaxMultiplier	- maximum digital magnification x100
+		bSourceID	- id of the terminal to which this unit is
+				connected
+		bUnitID		- a non-zero id of this unit
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/control/header
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Control header descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/control/header/name
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Specific control header descriptors
+
+dwClockFrequency
+bcdUVC
+What:		/config/usb-gadget/gadget/functions/uvc.name/streaming
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Streaming descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/streaming/class
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Streaming class descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/streaming/class/ss
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Super speed streaming class descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/streaming/class/hs
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	High speed streaming class descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/streaming/class/fs
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Full speed streaming class descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/streaming/color_matching
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Color matching descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/streaming/color_matching/default
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Default color matching descriptors
+
+		All attributes read only:
+		bMatrixCoefficients	- matrix used to compute luma and
+					chroma values from the color primaries
+		bTransferCharacteristics- optoelectronic transfer
+					characteristic of the source picutre,
+					also called the gamma function
+		bColorPrimaries		- color primaries and the reference
+					white
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/streaming/mjpeg
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	MJPEG format descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/streaming/mjpeg/name
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Specific MJPEG format descriptors
+
+		All attributes read only,
+		except bmaControls and bDefaultFrameIndex:
+		bmaControls		- this format's data for bmaControls in
+					the streaming header
+		bmInterfaceFlags	- specifies interlace information,
+					read-only
+		bAspectRatioY		- the X dimension of the picture aspect
+					ratio, read-only
+		bAspectRatioX		- the Y dimension of the picture aspect
+					ratio, read-only
+		bmFlags			- characteristics of this format,
+					read-only
+		bDefaultFrameIndex	- optimum frame index for this stream
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/streaming/mjpeg/name/name
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Specific MJPEG frame descriptors
+
+		dwFrameInterval		- indicates how frame interval can be
+					programmed; a number of values
+					separated by newline can be specified
+		dwDefaultFrameInterval	- the frame interval the device would
+					like to use as default
+		dwMaxVideoFrameBufferSize- the maximum number of bytes the
+					compressor will produce for a video
+					frame or still image
+		dwMaxBitRate		- the maximum bit rate at the shortest
+					frame interval in bps
+		dwMinBitRate		- the minimum bit rate at the longest
+					frame interval in bps
+		wHeight			- height of decoded bitmap frame in px
+		wWidth			- width of decoded bitmam frame in px
+		bmCapabilities		- still image support, fixed frame-rate
+					support
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/streaming/uncompressed
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Uncompressed format descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/streaming/uncompressed/name
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Specific uncompressed format descriptors
+
+		bmaControls		- this format's data for bmaControls in
+					the streaming header
+		bmInterfaceFlags	- specifies interlace information,
+					read-only
+		bAspectRatioY		- the X dimension of the picture aspect
+					ratio, read-only
+		bAspectRatioX		- the Y dimension of the picture aspect
+					ratio, read-only
+		bDefaultFrameIndex	- optimum frame index for this stream
+		bBitsPerPixel		- number of bits per pixel used to
+					specify color in the decoded video
+					frame
+		guidFormat		- globally unique id used to identify
+					stream-encoding format
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/streaming/uncompressed/name/name
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Specific uncompressed frame descriptors
+
+		dwFrameInterval		- indicates how frame interval can be
+					programmed; a number of values
+					separated by newline can be specified
+		dwDefaultFrameInterval	- the frame interval the device would
+					like to use as default
+		dwMaxVideoFrameBufferSize- the maximum number of bytes the
+					compressor will produce for a video
+					frame or still image
+		dwMaxBitRate		- the maximum bit rate at the shortest
+					frame interval in bps
+		dwMinBitRate		- the minimum bit rate at the longest
+					frame interval in bps
+		wHeight			- height of decoded bitmap frame in px
+		wWidth			- width of decoded bitmam frame in px
+		bmCapabilities		- still image support, fixed frame-rate
+					support
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/streaming/header
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Streaming header descriptors
+
+What:		/config/usb-gadget/gadget/functions/uvc.name/streaming/header/name
+Date:		Dec 2014
+KernelVersion:	3.20
+Description:	Specific streaming header descriptors
+
+		All attributes read only:
+		bTriggerUsage		- how the host software will respond to
+					a hardware trigger interrupt event
+		bTriggerSupport		- flag specifying if hardware
+					triggering is supported
+		bStillCaptureMethod	- method of still image caputre
+					supported
+		bTerminalLink		- id of the output terminal to which
+					the video endpoint of this interface
+					is connected
+		bmInfo			- capabilities of this video streaming
+					interface

drivers/usb/gadget/Kconfig

@@ -423,6 +423,17 @@ config USB_CONFIGFS_F_HID
 
 	  For more information, see Documentation/usb/gadget_hid.txt.
 
+config USB_CONFIGFS_F_UVC
+	boolean "USB Webcam function"
+	depends on USB_CONFIGFS
+	depends on VIDEO_DEV
+	select VIDEOBUF2_VMALLOC
+	select USB_F_UVC
+	help
+	  The Webcam function acts as a composite USB Audio and Video Class
+	  device. It provides a userspace API to process UVC control requests
+	  and stream video data to the host.
+
 source "drivers/usb/gadget/legacy/Kconfig"
 
 endchoice

drivers/usb/gadget/function/Makefile

@@ -36,7 +36,7 @@ usb_f_uac1-y			:= f_uac1.o u_uac1.o
 obj-$(CONFIG_USB_F_UAC1)	+= usb_f_uac1.o
 usb_f_uac2-y			:= f_uac2.o
 obj-$(CONFIG_USB_F_UAC2)	+= usb_f_uac2.o
-usb_f_uvc-y			:= f_uvc.o uvc_queue.o uvc_v4l2.o uvc_video.o
+usb_f_uvc-y			:= f_uvc.o uvc_queue.o uvc_v4l2.o uvc_video.o uvc_configfs.o
 obj-$(CONFIG_USB_F_UVC)		+= usb_f_uvc.o
 usb_f_midi-y			:= f_midi.o
 obj-$(CONFIG_USB_F_MIDI)	+= usb_f_midi.o

drivers/usb/gadget/function/f_uvc.c

@@ -27,10 +27,11 @@
 #include <media/v4l2-dev.h>
 #include <media/v4l2-event.h>
 
+#include "u_uvc.h"
 #include "uvc.h"
+#include "uvc_configfs.h"
 #include "uvc_v4l2.h"
 #include "uvc_video.h"
-#include "u_uvc.h"
 
 unsigned int uvc_gadget_trace_param;
 
@@ -788,25 +789,104 @@ static void uvc_free_inst(struct usb_function_instance *f)
 {
 	struct f_uvc_opts *opts = fi_to_f_uvc_opts(f);
 
+	mutex_destroy(&opts->lock);
 	kfree(opts);
 }
 
 static struct usb_function_instance *uvc_alloc_inst(void)
 {
 	struct f_uvc_opts *opts;
+	struct uvc_camera_terminal_descriptor *cd;
+	struct uvc_processing_unit_descriptor *pd;
+	struct uvc_output_terminal_descriptor *od;
+	struct uvc_color_matching_descriptor *md;
+	struct uvc_descriptor_header **ctl_cls;
 
 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 	if (!opts)
 		return ERR_PTR(-ENOMEM);
 	opts->func_inst.free_func_inst = uvc_free_inst;
-
+	mutex_init(&opts->lock);
+
+	cd = &opts->uvc_camera_terminal;
+	cd->bLength			= UVC_DT_CAMERA_TERMINAL_SIZE(3);
+	cd->bDescriptorType		= USB_DT_CS_INTERFACE;
+	cd->bDescriptorSubType		= UVC_VC_INPUT_TERMINAL;
+	cd->bTerminalID			= 1;
+	cd->wTerminalType		= cpu_to_le16(0x0201);
+	cd->bAssocTerminal		= 0;
+	cd->iTerminal			= 0;
+	cd->wObjectiveFocalLengthMin	= cpu_to_le16(0);
+	cd->wObjectiveFocalLengthMax	= cpu_to_le16(0);
+	cd->wOcularFocalLength		= cpu_to_le16(0);
+	cd->bControlSize		= 3;
+	cd->bmControls[0]		= 2;
+	cd->bmControls[1]		= 0;
+	cd->bmControls[2]		= 0;
+
+	pd = &opts->uvc_processing;
+	pd->bLength			= UVC_DT_PROCESSING_UNIT_SIZE(2);
+	pd->bDescriptorType		= USB_DT_CS_INTERFACE;
+	pd->bDescriptorSubType		= UVC_VC_PROCESSING_UNIT;
+	pd->bUnitID			= 2;
+	pd->bSourceID			= 1;
+	pd->wMaxMultiplier		= cpu_to_le16(16*1024);
+	pd->bControlSize		= 2;
+	pd->bmControls[0]		= 1;
+	pd->bmControls[1]		= 0;
+	pd->iProcessing			= 0;
+
+	od = &opts->uvc_output_terminal;
+	od->bLength			= UVC_DT_OUTPUT_TERMINAL_SIZE;
+	od->bDescriptorType		= USB_DT_CS_INTERFACE;
+	od->bDescriptorSubType		= UVC_VC_OUTPUT_TERMINAL;
+	od->bTerminalID			= 3;
+	od->wTerminalType		= cpu_to_le16(0x0101);
+	od->bAssocTerminal		= 0;
+	od->bSourceID			= 2;
+	od->iTerminal			= 0;
+
+	md = &opts->uvc_color_matching;
+	md->bLength			= UVC_DT_COLOR_MATCHING_SIZE;
+	md->bDescriptorType		= USB_DT_CS_INTERFACE;
+	md->bDescriptorSubType		= UVC_VS_COLORFORMAT;
+	md->bColorPrimaries		= 1;
+	md->bTransferCharacteristics	= 1;
+	md->bMatrixCoefficients		= 4;
+
+	/* Prepare fs control class descriptors for configfs-based gadgets */
+	ctl_cls = opts->uvc_fs_control_cls;
+	ctl_cls[0] = NULL;	/* assigned elsewhere by configfs */
+	ctl_cls[1] = (struct uvc_descriptor_header *)cd;
+	ctl_cls[2] = (struct uvc_descriptor_header *)pd;
+	ctl_cls[3] = (struct uvc_descriptor_header *)od;
+	ctl_cls[4] = NULL;	/* NULL-terminate */
+	opts->fs_control =
+		(const struct uvc_descriptor_header * const *)ctl_cls;
+
+	/* Prepare hs control class descriptors for configfs-based gadgets */
+	ctl_cls = opts->uvc_ss_control_cls;
+	ctl_cls[0] = NULL;	/* assigned elsewhere by configfs */
+	ctl_cls[1] = (struct uvc_descriptor_header *)cd;
+	ctl_cls[2] = (struct uvc_descriptor_header *)pd;
+	ctl_cls[3] = (struct uvc_descriptor_header *)od;
+	ctl_cls[4] = NULL;	/* NULL-terminate */
+	opts->ss_control =
+		(const struct uvc_descriptor_header * const *)ctl_cls;
+
+	opts->streaming_interval = 1;
+	opts->streaming_maxpacket = 1024;
+
+	uvcg_attach_configfs(opts);
 	return &opts->func_inst;
 }
 
 static void uvc_free(struct usb_function *f)
 {
 	struct uvc_device *uvc = to_uvc(f);
-
+	struct f_uvc_opts *opts = container_of(f->fi, struct f_uvc_opts,
+					       func_inst);
+	--opts->refcnt;
 	kfree(uvc);
 }
 
@@ -832,6 +912,7 @@ static struct usb_function *uvc_alloc(struct usb_function_instance *fi)
 {
 	struct uvc_device *uvc;
 	struct f_uvc_opts *opts;
+	struct uvc_descriptor_header **strm_cls;
 
 	uvc = kzalloc(sizeof(*uvc), GFP_KERNEL);
 	if (uvc == NULL)
@@ -840,11 +921,30 @@ static struct usb_function *uvc_alloc(struct usb_function_instance *fi)
 	uvc->state = UVC_STATE_DISCONNECTED;
 	opts = fi_to_f_uvc_opts(fi);
 
+	mutex_lock(&opts->lock);
+	if (opts->uvc_fs_streaming_cls) {
+		strm_cls = opts->uvc_fs_streaming_cls;
+		opts->fs_streaming =
+			(const struct uvc_descriptor_header * const *)strm_cls;
+	}
+	if (opts->uvc_hs_streaming_cls) {
+		strm_cls = opts->uvc_hs_streaming_cls;
+		opts->hs_streaming =
+			(const struct uvc_descriptor_header * const *)strm_cls;
+	}
+	if (opts->uvc_ss_streaming_cls) {
+		strm_cls = opts->uvc_ss_streaming_cls;
+		opts->ss_streaming =
+			(const struct uvc_descriptor_header * const *)strm_cls;
+	}
+
 	uvc->desc.fs_control = opts->fs_control;
 	uvc->desc.ss_control = opts->ss_control;
 	uvc->desc.fs_streaming = opts->fs_streaming;
 	uvc->desc.hs_streaming = opts->hs_streaming;
 	uvc->desc.ss_streaming = opts->ss_streaming;
+	++opts->refcnt;
+	mutex_unlock(&opts->lock);
 
 	/* Register the function. */
 	uvc->func.name = "uvc";

drivers/usb/gadget/function/u_uvc.h

@@ -17,6 +17,7 @@
 #define U_UVC_H
 
 #include <linux/usb/composite.h>
+#include <linux/usb/video.h>
 
 #define fi_to_f_uvc_opts(f)	container_of(f, struct f_uvc_opts, func_inst)
 
@@ -26,11 +27,60 @@ struct f_uvc_opts {
 	unsigned int					streaming_interval;
 	unsigned int					streaming_maxpacket;
 	unsigned int					streaming_maxburst;
+
+	/*
+	 * Control descriptors array pointers for full-/high-speed and
+	 * super-speed. They point by default to the uvc_fs_control_cls and
+	 * uvc_ss_control_cls arrays respectively. Legacy gadgets must
+	 * override them in their gadget bind callback.
+	 */
 	const struct uvc_descriptor_header * const	*fs_control;
 	const struct uvc_descriptor_header * const	*ss_control;
+
+	/*
+	 * Streaming descriptors array pointers for full-speed, high-speed and
+	 * super-speed. They will point to the uvc_[fhs]s_streaming_cls arrays
+	 * for configfs-based gadgets. Legacy gadgets must initialize them in
+	 * their gadget bind callback.
+	 */
 	const struct uvc_descriptor_header * const	*fs_streaming;
 	const struct uvc_descriptor_header * const	*hs_streaming;
 	const struct uvc_descriptor_header * const	*ss_streaming;
+
+	/* Default control descriptors for configfs-based gadgets. */
+	struct uvc_camera_terminal_descriptor		uvc_camera_terminal;
+	struct uvc_processing_unit_descriptor		uvc_processing;
+	struct uvc_output_terminal_descriptor		uvc_output_terminal;
+	struct uvc_color_matching_descriptor		uvc_color_matching;
+
+	/*
+	 * Control descriptors pointers arrays for full-/high-speed and
+	 * super-speed. The first element is a configurable control header
+	 * descriptor, the other elements point to the fixed default control
+	 * descriptors. Used by configfs only, must not be touched by legacy
+	 * gadgets.
+	 */
+	struct uvc_descriptor_header			*uvc_fs_control_cls[5];
+	struct uvc_descriptor_header			*uvc_ss_control_cls[5];
+
+	/*
+	 * Streaming descriptors for full-speed, high-speed and super-speed.
+	 * Used by configfs only, must not be touched by legacy gadgets. The
+	 * arrays are allocated at runtime as the number of descriptors isn't
+	 * known in advance.
+	 */
+	struct uvc_descriptor_header			**uvc_fs_streaming_cls;
+	struct uvc_descriptor_header			**uvc_hs_streaming_cls;
+	struct uvc_descriptor_header			**uvc_ss_streaming_cls;
+
+	/*
+	 * Read/write access to configfs attributes is handled by configfs.
+	 *
+	 * This lock protects the descriptors from concurrent access by
+	 * read/write and symlink creation/removal.
+	 */
+	struct mutex			lock;
+	int				refcnt;
 };
 
 void uvc_set_trace_param(unsigned int trace);

drivers/usb/gadget/function/uvc_configfs.c

+/*
+ * uvc_configfs.c
+ *
+ * Configfs support for the uvc function.
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ *		http://www.samsung.com
+ *
+ * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include "u_uvc.h"
+#include "uvc_configfs.h"
+
+#define UVCG_STREAMING_CONTROL_SIZE	1
+
+#define CONFIGFS_ATTR_OPS_RO(_item)					\
+static ssize_t _item##_attr_show(struct config_item *item,		\
+				 struct configfs_attribute *attr,	\
+				 char *page)				\
+{									\
+	struct _item *_item = to_##_item(item);				\
+	struct _item##_attribute *_item##_attr =			\
+		container_of(attr, struct _item##_attribute, attr);	\
+	ssize_t ret = 0;						\
+									\
+	if (_item##_attr->show)						\
+		ret = _item##_attr->show(_item, page);			\
+	return ret;							\
+}
+
+static inline struct f_uvc_opts *to_f_uvc_opts(struct config_item *item);
+
+/* control/header/<NAME> */
+DECLARE_UVC_HEADER_DESCRIPTOR(1);
+
+struct uvcg_control_header {
+	struct config_item		item;
+	struct UVC_HEADER_DESCRIPTOR(1)	desc;
+	unsigned			linked;
+};
+
+struct uvcg_control_header *to_uvcg_control_header(struct config_item *item)
+{
+	return container_of(item, struct uvcg_control_header, item);
+}
+
+CONFIGFS_ATTR_STRUCT(uvcg_control_header);
+CONFIGFS_ATTR_OPS(uvcg_control_header);
+
+static struct configfs_item_operations uvcg_control_header_item_ops = {
+	.show_attribute		= uvcg_control_header_attr_show,
+	.store_attribute	= uvcg_control_header_attr_store,
+};
+
+#define UVCG_CTRL_HDR_ATTR(cname, aname, conv, str2u, uxx, vnoc, limit)	\
+static ssize_t uvcg_control_header_##cname##_show(			\
+	struct uvcg_control_header *ch, char *page)			\
+{									\
+	struct f_uvc_opts *opts;					\
+	struct config_item *opts_item;					\
+	struct mutex *su_mutex = &ch->item.ci_group->cg_subsys->su_mutex;\
+	int result;							\
+									\
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
+									\
+	opts_item = ch->item.ci_parent->ci_parent->ci_parent;		\
+	opts = to_f_uvc_opts(opts_item);				\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%d\n", conv(ch->desc.aname));		\
+	mutex_unlock(&opts->lock);					\
+									\
+	mutex_unlock(su_mutex);						\
+	return result;							\
+}									\
+									\
+static ssize_t								\
+uvcg_control_header_##cname##_store(struct uvcg_control_header *ch,	\
+			   const char *page, size_t len)		\
+{									\
+	struct f_uvc_opts *opts;					\
+	struct config_item *opts_item;					\
+	struct mutex *su_mutex = &ch->item.ci_group->cg_subsys->su_mutex;\
+	int ret;							\
+	uxx num;							\
+									\
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
+									\
+	opts_item = ch->item.ci_parent->ci_parent->ci_parent;		\
+	opts = to_f_uvc_opts(opts_item);				\
+									\
+	mutex_lock(&opts->lock);					\
+	if (ch->linked || opts->refcnt) {				\
+		ret = -EBUSY;						\
+		goto end;						\
+	}								\
+									\
+	ret = str2u(page, 0, &num);					\
+	if (ret)							\
+		goto end;						\
+									\
+	if (num > limit) {						\
+		ret = -EINVAL;						\
+		goto end;						\
+	}								\
+	ch->desc.aname = vnoc(num);					\
+	ret = len;							\
+end:									\
+	mutex_unlock(&opts->lock);					\
+	mutex_unlock(su_mutex);						\
+	return ret;							\
+}									\
+									\
+static struct uvcg_control_header_attribute				\
+	uvcg_control_header_##cname =					\
+	__CONFIGFS_ATTR(aname, S_IRUGO | S_IWUSR,			\
+			uvcg_control_header_##cname##_show,		\
+			uvcg_control_header_##cname##_store)
+
+UVCG_CTRL_HDR_ATTR(bcd_uvc, bcdUVC, le16_to_cpu, kstrtou16, u16, cpu_to_le16,
+		   0xffff);
+
+UVCG_CTRL_HDR_ATTR(dw_clock_frequency, dwClockFrequency, le32_to_cpu, kstrtou32,
+		   u32, cpu_to_le32, 0x7fffffff);
+
+#undef UVCG_CTRL_HDR_ATTR
+
+static struct configfs_attribute *uvcg_control_header_attrs[] = {
+	&uvcg_control_header_bcd_uvc.attr,
+	&uvcg_control_header_dw_clock_frequency.attr,
+	NULL,
+};
+
+struct config_item_type uvcg_control_header_type = {
+	.ct_item_ops	= &uvcg_control_header_item_ops,
+	.ct_attrs	= uvcg_control_header_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_item *uvcg_control_header_make(struct config_group *group,
+						    const char *name)
+{
+	struct uvcg_control_header *h;
+
+	h = kzalloc(sizeof(*h), GFP_KERNEL);
+	if (!h)
+		return ERR_CAST(h);
+
+	h->desc.bLength			= UVC_DT_HEADER_SIZE(1);
+	h->desc.bDescriptorType		= USB_DT_CS_INTERFACE;
+	h->desc.bDescriptorSubType	= UVC_VC_HEADER;
+	h->desc.bcdUVC			= cpu_to_le16(0x0100);
+	h->desc.dwClockFrequency	= cpu_to_le32(48000000);
+
+	config_item_init_type_name(&h->item, name, &uvcg_control_header_type);
+
+	return &h->item;
+}
+
+void uvcg_control_header_drop(struct config_group *group,
+			      struct config_item *item)
+{
+	struct uvcg_control_header *h = to_uvcg_control_header(item);
+
+	kfree(h);
+}
+
+/* control/header */
+static struct uvcg_control_header_grp {
+	struct config_group	group;
+} uvcg_control_header_grp;
+
+static struct configfs_group_operations uvcg_control_header_grp_ops = {
+	.make_item		= uvcg_control_header_make,
+	.drop_item		= uvcg_control_header_drop,
+};
+
+static struct config_item_type uvcg_control_header_grp_type = {
+	.ct_group_ops	= &uvcg_control_header_grp_ops,
+	.ct_owner	= THIS_MODULE,
+};
+
+/* control/processing/default */
+static struct uvcg_default_processing {
+	struct config_group	group;
+} uvcg_default_processing;
+
+static inline struct uvcg_default_processing
+*to_uvcg_default_processing(struct config_item *item)
+{
+	return container_of(to_config_group(item),
+			    struct uvcg_default_processing, group);
+}
+
+CONFIGFS_ATTR_STRUCT(uvcg_default_processing);
+CONFIGFS_ATTR_OPS_RO(uvcg_default_processing);
+
+static struct configfs_item_operations uvcg_default_processing_item_ops = {
+	.show_attribute		= uvcg_default_processing_attr_show,
+};
+
+#define UVCG_DEFAULT_PROCESSING_ATTR(cname, aname, conv)		\
+static ssize_t uvcg_default_processing_##cname##_show(			\
+	struct uvcg_default_processing *dp, char *page)			\
+{									\
+	struct f_uvc_opts *opts;					\
+	struct config_item *opts_item;					\
+	struct mutex *su_mutex = &dp->group.cg_subsys->su_mutex;	\
+	struct uvc_processing_unit_descriptor *pd;			\
+	int result;							\
+									\
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
+									\
+	opts_item = dp->group.cg_item.ci_parent->ci_parent->ci_parent;	\
+	opts = to_f_uvc_opts(opts_item);				\
+	pd = &opts->uvc_processing;					\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%d\n", conv(pd->aname));		\
+	mutex_unlock(&opts->lock);					\
+									\
+	mutex_unlock(su_mutex);						\
+	return result;							\
+}									\
+									\
+static struct uvcg_default_processing_attribute				\
+	uvcg_default_processing_##cname =				\
+	__CONFIGFS_ATTR_RO(aname, uvcg_default_processing_##cname##_show)
+
+#define identity_conv(x) (x)
+
+UVCG_DEFAULT_PROCESSING_ATTR(b_unit_id, bUnitID, identity_conv);
+UVCG_DEFAULT_PROCESSING_ATTR(b_source_id, bSourceID, identity_conv);
+UVCG_DEFAULT_PROCESSING_ATTR(w_max_multiplier, wMaxMultiplier, le16_to_cpu);
+UVCG_DEFAULT_PROCESSING_ATTR(i_processing, iProcessing, identity_conv);
+
+#undef identity_conv
+
+#undef UVCG_DEFAULT_PROCESSING_ATTR
+
+static ssize_t uvcg_default_processing_bm_controls_show(
+	struct uvcg_default_processing *dp, char *page)
+{
+	struct f_uvc_opts *opts;
+	struct config_item *opts_item;
+	struct mutex *su_mutex = &dp->group.cg_subsys->su_mutex;
+	struct uvc_processing_unit_descriptor *pd;
+	int result, i;
+	char *pg = page;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	opts_item = dp->group.cg_item.ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+	pd = &opts->uvc_processing;
+
+	mutex_lock(&opts->lock);
+	for (result = 0, i = 0; i < pd->bControlSize; ++i) {
+		result += sprintf(pg, "%d\n", pd->bmControls[i]);
+		pg = page + result;
+	}
+	mutex_unlock(&opts->lock);
+
+	mutex_unlock(su_mutex);
+
+	return result;
+}
+
+static struct uvcg_default_processing_attribute
+	uvcg_default_processing_bm_controls =
+	__CONFIGFS_ATTR_RO(bmControls,
+		uvcg_default_processing_bm_controls_show);
+
+static struct configfs_attribute *uvcg_default_processing_attrs[] = {
+	&uvcg_default_processing_b_unit_id.attr,
+	&uvcg_default_processing_b_source_id.attr,
+	&uvcg_default_processing_w_max_multiplier.attr,
+	&uvcg_default_processing_bm_controls.attr,
+	&uvcg_default_processing_i_processing.attr,
+	NULL,
+};
+
+static struct config_item_type uvcg_default_processing_type = {
+	.ct_item_ops	= &uvcg_default_processing_item_ops,
+	.ct_attrs	= uvcg_default_processing_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+/* struct uvcg_processing {}; */
+
+static struct config_group *uvcg_processing_default_groups[] = {
+	&uvcg_default_processing.group,
+	NULL,
+};
+
+/* control/processing */
+static struct uvcg_processing_grp {
+	struct config_group	group;
+} uvcg_processing_grp;
+
+static struct config_item_type uvcg_processing_grp_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+/* control/terminal/camera/default */
+static struct uvcg_default_camera {
+	struct config_group	group;
+} uvcg_default_camera;
+
+static inline struct uvcg_default_camera
+*to_uvcg_default_camera(struct config_item *item)
+{
+	return container_of(to_config_group(item),
+			    struct uvcg_default_camera, group);
+}
+
+CONFIGFS_ATTR_STRUCT(uvcg_default_camera);
+CONFIGFS_ATTR_OPS_RO(uvcg_default_camera);
+
+static struct configfs_item_operations uvcg_default_camera_item_ops = {
+	.show_attribute		= uvcg_default_camera_attr_show,
+};
+
+#define UVCG_DEFAULT_CAMERA_ATTR(cname, aname, conv)			\
+static ssize_t uvcg_default_camera_##cname##_show(			\
+	struct uvcg_default_camera *dc, char *page)			\
+{									\
+	struct f_uvc_opts *opts;					\
+	struct config_item *opts_item;					\
+	struct mutex *su_mutex = &dc->group.cg_subsys->su_mutex;	\
+	struct uvc_camera_terminal_descriptor *cd;			\
+	int result;							\
+									\
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
+									\
+	opts_item = dc->group.cg_item.ci_parent->ci_parent->ci_parent->	\
+			ci_parent;					\
+	opts = to_f_uvc_opts(opts_item);				\
+	cd = &opts->uvc_camera_terminal;				\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%d\n", conv(cd->aname));		\
+	mutex_unlock(&opts->lock);					\
+									\
+	mutex_unlock(su_mutex);						\
+									\
+	return result;							\
+}									\
+									\
+static struct uvcg_default_camera_attribute				\
+	uvcg_default_camera_##cname =					\
+	__CONFIGFS_ATTR_RO(aname, uvcg_default_camera_##cname##_show)
+
+#define identity_conv(x) (x)
+
+UVCG_DEFAULT_CAMERA_ATTR(b_terminal_id, bTerminalID, identity_conv);
+UVCG_DEFAULT_CAMERA_ATTR(w_terminal_type, wTerminalType, le16_to_cpu);
+UVCG_DEFAULT_CAMERA_ATTR(b_assoc_terminal, bAssocTerminal, identity_conv);
+UVCG_DEFAULT_CAMERA_ATTR(i_terminal, iTerminal, identity_conv);
+UVCG_DEFAULT_CAMERA_ATTR(w_objective_focal_length_min, wObjectiveFocalLengthMin,
+			 le16_to_cpu);
+UVCG_DEFAULT_CAMERA_ATTR(w_objective_focal_length_max, wObjectiveFocalLengthMax,
+			 le16_to_cpu);
+UVCG_DEFAULT_CAMERA_ATTR(w_ocular_focal_length, wOcularFocalLength,
+			 le16_to_cpu);
+
+#undef identity_conv
+
+#undef UVCG_DEFAULT_CAMERA_ATTR
+
+static ssize_t uvcg_default_camera_bm_controls_show(
+	struct uvcg_default_camera *dc, char *page)
+{
+	struct f_uvc_opts *opts;
+	struct config_item *opts_item;
+	struct mutex *su_mutex = &dc->group.cg_subsys->su_mutex;
+	struct uvc_camera_terminal_descriptor *cd;
+	int result, i;
+	char *pg = page;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	opts_item = dc->group.cg_item.ci_parent->ci_parent->ci_parent->
+			ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+	cd = &opts->uvc_camera_terminal;
+
+	mutex_lock(&opts->lock);
+	for (result = 0, i = 0; i < cd->bControlSize; ++i) {
+		result += sprintf(pg, "%d\n", cd->bmControls[i]);
+		pg = page + result;
+	}
+	mutex_unlock(&opts->lock);
+
+	mutex_unlock(su_mutex);
+	return result;
+}
+
+static struct uvcg_default_camera_attribute
+	uvcg_default_camera_bm_controls =
+	__CONFIGFS_ATTR_RO(bmControls, uvcg_default_camera_bm_controls_show);
+
+static struct configfs_attribute *uvcg_default_camera_attrs[] = {
+	&uvcg_default_camera_b_terminal_id.attr,
+	&uvcg_default_camera_w_terminal_type.attr,
+	&uvcg_default_camera_b_assoc_terminal.attr,
+	&uvcg_default_camera_i_terminal.attr,
+	&uvcg_default_camera_w_objective_focal_length_min.attr,
+	&uvcg_default_camera_w_objective_focal_length_max.attr,
+	&uvcg_default_camera_w_ocular_focal_length.attr,
+	&uvcg_default_camera_bm_controls.attr,
+	NULL,
+};
+
+static struct config_item_type uvcg_default_camera_type = {
+	.ct_item_ops	= &uvcg_default_camera_item_ops,
+	.ct_attrs	= uvcg_default_camera_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+/* struct uvcg_camera {}; */
+
+static struct config_group *uvcg_camera_default_groups[] = {
+	&uvcg_default_camera.group,
+	NULL,
+};
+
+/* control/terminal/camera */
+static struct uvcg_camera_grp {
+	struct config_group	group;
+} uvcg_camera_grp;
+
+static struct config_item_type uvcg_camera_grp_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+/* control/terminal/output/default */
+static struct uvcg_default_output {
+	struct config_group	group;
+} uvcg_default_output;
+
+static inline struct uvcg_default_output
+*to_uvcg_default_output(struct config_item *item)
+{
+	return container_of(to_config_group(item),
+			    struct uvcg_default_output, group);
+}
+
+CONFIGFS_ATTR_STRUCT(uvcg_default_output);
+CONFIGFS_ATTR_OPS_RO(uvcg_default_output);
+
+static struct configfs_item_operations uvcg_default_output_item_ops = {
+	.show_attribute		= uvcg_default_output_attr_show,
+};
+
+#define UVCG_DEFAULT_OUTPUT_ATTR(cname, aname, conv)			\
+static ssize_t uvcg_default_output_##cname##_show(			\
+	struct uvcg_default_output *dout, char *page)			\
+{									\
+	struct f_uvc_opts *opts;					\
+	struct config_item *opts_item;					\
+	struct mutex *su_mutex = &dout->group.cg_subsys->su_mutex;	\
+	struct uvc_output_terminal_descriptor *cd;			\
+	int result;							\
+									\
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
+									\
+	opts_item = dout->group.cg_item.ci_parent->ci_parent->		\
+			ci_parent->ci_parent;				\
+	opts = to_f_uvc_opts(opts_item);				\
+	cd = &opts->uvc_output_terminal;				\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%d\n", conv(cd->aname));		\
+	mutex_unlock(&opts->lock);					\
+									\
+	mutex_unlock(su_mutex);						\
+									\
+	return result;							\
+}									\
+									\
+static struct uvcg_default_output_attribute				\
+	uvcg_default_output_##cname =					\
+	__CONFIGFS_ATTR_RO(aname, uvcg_default_output_##cname##_show)
+
+#define identity_conv(x) (x)
+
+UVCG_DEFAULT_OUTPUT_ATTR(b_terminal_id, bTerminalID, identity_conv);
+UVCG_DEFAULT_OUTPUT_ATTR(w_terminal_type, wTerminalType, le16_to_cpu);
+UVCG_DEFAULT_OUTPUT_ATTR(b_assoc_terminal, bAssocTerminal, identity_conv);
+UVCG_DEFAULT_OUTPUT_ATTR(b_source_id, bSourceID, identity_conv);
+UVCG_DEFAULT_OUTPUT_ATTR(i_terminal, iTerminal, identity_conv);
+
+#undef identity_conv
+
+#undef UVCG_DEFAULT_OUTPUT_ATTR
+
+static struct configfs_attribute *uvcg_default_output_attrs[] = {
+	&uvcg_default_output_b_terminal_id.attr,
+	&uvcg_default_output_w_terminal_type.attr,
+	&uvcg_default_output_b_assoc_terminal.attr,
+	&uvcg_default_output_b_source_id.attr,
+	&uvcg_default_output_i_terminal.attr,
+	NULL,
+};
+
+static struct config_item_type uvcg_default_output_type = {
+	.ct_item_ops	= &uvcg_default_output_item_ops,
+	.ct_attrs	= uvcg_default_output_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+/* struct uvcg_output {}; */
+
+static struct config_group *uvcg_output_default_groups[] = {
+	&uvcg_default_output.group,
+	NULL,
+};
+
+/* control/terminal/output */
+static struct uvcg_output_grp {
+	struct config_group	group;
+} uvcg_output_grp;
+
+static struct config_item_type uvcg_output_grp_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+static struct config_group *uvcg_terminal_default_groups[] = {
+	&uvcg_camera_grp.group,
+	&uvcg_output_grp.group,
+	NULL,
+};
+
+/* control/terminal */
+static struct uvcg_terminal_grp {
+	struct config_group	group;
+} uvcg_terminal_grp;
+
+static struct config_item_type uvcg_terminal_grp_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+/* control/class/{fs} */
+static struct uvcg_control_class {
+	struct config_group	group;
+} uvcg_control_class_fs, uvcg_control_class_ss;
+
+
+static inline struct uvc_descriptor_header
+**uvcg_get_ctl_class_arr(struct config_item *i, struct f_uvc_opts *o)
+{
+	struct uvcg_control_class *cl = container_of(to_config_group(i),
+		struct uvcg_control_class, group);
+
+	if (cl == &uvcg_control_class_fs)
+		return o->uvc_fs_control_cls;
+
+	if (cl == &uvcg_control_class_ss)
+		return o->uvc_ss_control_cls;
+
+	return NULL;
+}
+
+static int uvcg_control_class_allow_link(struct config_item *src,
+					 struct config_item *target)
+{
+	struct config_item *control, *header;
+	struct f_uvc_opts *opts;
+	struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
+	struct uvc_descriptor_header **class_array;
+	struct uvcg_control_header *target_hdr;
+	int ret = -EINVAL;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	control = src->ci_parent->ci_parent;
+	header = config_group_find_item(to_config_group(control), "header");
+	if (!header || target->ci_parent != header)
+		goto out;
+
+	opts = to_f_uvc_opts(control->ci_parent);
+
+	mutex_lock(&opts->lock);
+
+	class_array = uvcg_get_ctl_class_arr(src, opts);
+	if (!class_array)
+		goto unlock;
+	if (opts->refcnt || class_array[0]) {
+		ret = -EBUSY;
+		goto unlock;
+	}
+
+	target_hdr = to_uvcg_control_header(target);
+	++target_hdr->linked;
+	class_array[0] = (struct uvc_descriptor_header *)&target_hdr->desc;
+	ret = 0;
+
+unlock:
+	mutex_unlock(&opts->lock);
+out:
+	mutex_unlock(su_mutex);
+	return ret;
+}
+
+static int uvcg_control_class_drop_link(struct config_item *src,
+					struct config_item *target)
+{
+	struct config_item *control, *header;
+	struct f_uvc_opts *opts;
+	struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
+	struct uvc_descriptor_header **class_array;
+	struct uvcg_control_header *target_hdr;
+	int ret = -EINVAL;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	control = src->ci_parent->ci_parent;
+	header = config_group_find_item(to_config_group(control), "header");
+	if (!header || target->ci_parent != header)
+		goto out;
+
+	opts = to_f_uvc_opts(control->ci_parent);
+
+	mutex_lock(&opts->lock);
+
+	class_array = uvcg_get_ctl_class_arr(src, opts);
+	if (!class_array)
+		goto unlock;
+	if (opts->refcnt) {
+		ret = -EBUSY;
+		goto unlock;
+	}
+
+	target_hdr = to_uvcg_control_header(target);
+	--target_hdr->linked;
+	class_array[0] = NULL;
+	ret = 0;
+
+unlock:
+	mutex_unlock(&opts->lock);
+out:
+	mutex_unlock(su_mutex);
+	return ret;
+}
+
+static struct configfs_item_operations uvcg_control_class_item_ops = {
+	.allow_link	= uvcg_control_class_allow_link,
+	.drop_link	= uvcg_control_class_drop_link,
+};
+
+static struct config_item_type uvcg_control_class_type = {
+	.ct_item_ops	= &uvcg_control_class_item_ops,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_group *uvcg_control_class_default_groups[] = {
+	&uvcg_control_class_fs.group,
+	&uvcg_control_class_ss.group,
+	NULL,
+};
+
+/* control/class */
+static struct uvcg_control_class_grp {
+	struct config_group	group;
+} uvcg_control_class_grp;
+
+static struct config_item_type uvcg_control_class_grp_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+static struct config_group *uvcg_control_default_groups[] = {
+	&uvcg_control_header_grp.group,
+	&uvcg_processing_grp.group,
+	&uvcg_terminal_grp.group,
+	&uvcg_control_class_grp.group,
+	NULL,
+};
+
+/* control */
+static struct uvcg_control_grp {
+	struct config_group	group;
+} uvcg_control_grp;
+
+static struct config_item_type uvcg_control_grp_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+/* streaming/uncompressed */
+static struct uvcg_uncompressed_grp {
+	struct config_group	group;
+} uvcg_uncompressed_grp;
+
+/* streaming/mjpeg */
+static struct uvcg_mjpeg_grp {
+	struct config_group	group;
+} uvcg_mjpeg_grp;
+
+static struct config_item *fmt_parent[] = {
+	&uvcg_uncompressed_grp.group.cg_item,
+	&uvcg_mjpeg_grp.group.cg_item,
+};
+
+enum uvcg_format_type {
+	UVCG_UNCOMPRESSED = 0,
+	UVCG_MJPEG,
+};
+
+struct uvcg_format {
+	struct config_group	group;
+	enum uvcg_format_type	type;
+	unsigned		linked;
+	unsigned		num_frames;
+	__u8			bmaControls[UVCG_STREAMING_CONTROL_SIZE];
+};
+
+struct uvcg_format *to_uvcg_format(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct uvcg_format, group);
+}
+
+static ssize_t uvcg_format_bma_controls_show(struct uvcg_format *f, char *page)
+{
+	struct f_uvc_opts *opts;
+	struct config_item *opts_item;
+	struct mutex *su_mutex = &f->group.cg_subsys->su_mutex;
+	int result, i;
+	char *pg = page;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	opts_item = f->group.cg_item.ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+	result = sprintf(pg, "0x");
+	pg += result;
+	for (i = 0; i < UVCG_STREAMING_CONTROL_SIZE; ++i) {
+		result += sprintf(pg, "%x\n", f->bmaControls[i]);
+		pg = page + result;
+	}
+	mutex_unlock(&opts->lock);
+
+	mutex_unlock(su_mutex);
+	return result;
+}
+
+static ssize_t uvcg_format_bma_controls_store(struct uvcg_format *ch,
+					      const char *page, size_t len)
+{
+	struct f_uvc_opts *opts;
+	struct config_item *opts_item;
+	struct mutex *su_mutex = &ch->group.cg_subsys->su_mutex;
+	int ret = -EINVAL;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	opts_item = ch->group.cg_item.ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+	if (ch->linked || opts->refcnt) {
+		ret = -EBUSY;
+		goto end;
+	}
+
+	if (len < 4 || *page != '0' ||
+	    (*(page + 1) != 'x' && *(page + 1) != 'X'))
+		goto end;
+	ret = hex2bin(ch->bmaControls, page + 2, 1);
+	if (ret < 0)
+		goto end;
+	ret = len;
+end:
+	mutex_unlock(&opts->lock);
+	mutex_unlock(su_mutex);
+	return ret;
+}
+
+struct uvcg_format_ptr {
+	struct uvcg_format	*fmt;
+	struct list_head	entry;
+};
+
+/* streaming/header/<NAME> */
+struct uvcg_streaming_header {
+	struct config_item				item;
+	struct uvc_input_header_descriptor		desc;
+	unsigned					linked;
+	struct list_head				formats;
+	unsigned					num_fmt;
+};
+
+struct uvcg_streaming_header *to_uvcg_streaming_header(struct config_item *item)
+{
+	return container_of(item, struct uvcg_streaming_header, item);
+}
+
+CONFIGFS_ATTR_STRUCT(uvcg_streaming_header);
+CONFIGFS_ATTR_OPS(uvcg_streaming_header);
+
+static int uvcg_streaming_header_allow_link(struct config_item *src,
+					    struct config_item *target)
+{
+	struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
+	struct config_item *opts_item;
+	struct f_uvc_opts *opts;
+	struct uvcg_streaming_header *src_hdr;
+	struct uvcg_format *target_fmt = NULL;
+	struct uvcg_format_ptr *format_ptr;
+	int i, ret = -EINVAL;
+
+	src_hdr = to_uvcg_streaming_header(src);
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	opts_item = src->ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+
+	if (src_hdr->linked) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(fmt_parent); ++i)
+		if (target->ci_parent == fmt_parent[i])
+			break;
+	if (i == ARRAY_SIZE(fmt_parent))
+		goto out;
+
+	target_fmt = container_of(to_config_group(target), struct uvcg_format,
+				  group);
+	if (!target_fmt)
+		goto out;
+
+	format_ptr = kzalloc(sizeof(*format_ptr), GFP_KERNEL);
+	if (!format_ptr) {
+		ret = PTR_ERR(format_ptr);
+		goto out;
+	}
+	ret = 0;
+	format_ptr->fmt = target_fmt;
+	list_add_tail(&format_ptr->entry, &src_hdr->formats);
+	++src_hdr->num_fmt;
+
+out:
+	mutex_unlock(&opts->lock);
+	mutex_unlock(su_mutex);
+	return ret;
+}
+
+static int uvcg_streaming_header_drop_link(struct config_item *src,
+					   struct config_item *target)
+{
+	struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
+	struct config_item *opts_item;
+	struct f_uvc_opts *opts;
+	struct uvcg_streaming_header *src_hdr;
+	struct uvcg_format *target_fmt = NULL;
+	struct uvcg_format_ptr *format_ptr, *tmp;
+	int ret = -EINVAL;
+
+	src_hdr = to_uvcg_streaming_header(src);
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	opts_item = src->ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+	target_fmt = container_of(to_config_group(target), struct uvcg_format,
+				  group);
+	if (!target_fmt)
+		goto out;
+
+	list_for_each_entry_safe(format_ptr, tmp, &src_hdr->formats, entry)
+		if (format_ptr->fmt == target_fmt) {
+			list_del(&format_ptr->entry);
+			kfree(format_ptr);
+			--src_hdr->num_fmt;
+			break;
+		}
+
+out:
+	mutex_unlock(&opts->lock);
+	mutex_unlock(su_mutex);
+	return ret;
+
+}
+
+static struct configfs_item_operations uvcg_streaming_header_item_ops = {
+	.show_attribute		= uvcg_streaming_header_attr_show,
+	.store_attribute	= uvcg_streaming_header_attr_store,
+	.allow_link		= uvcg_streaming_header_allow_link,
+	.drop_link		= uvcg_streaming_header_drop_link,
+};
+
+#define UVCG_STREAMING_HEADER_ATTR(cname, aname, conv)			\
+static ssize_t uvcg_streaming_header_##cname##_show(			\
+	struct uvcg_streaming_header *sh, char *page)			\
+{									\
+	struct f_uvc_opts *opts;					\
+	struct config_item *opts_item;					\
+	struct mutex *su_mutex = &sh->item.ci_group->cg_subsys->su_mutex;\
+	int result;							\
+									\
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
+									\
+	opts_item = sh->item.ci_parent->ci_parent->ci_parent;		\
+	opts = to_f_uvc_opts(opts_item);				\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%d\n", conv(sh->desc.aname));		\
+	mutex_unlock(&opts->lock);					\
+									\
+	mutex_unlock(su_mutex);						\
+	return result;							\
+}									\
+									\
+static struct uvcg_streaming_header_attribute				\
+	uvcg_streaming_header_##cname =					\
+	__CONFIGFS_ATTR_RO(aname, uvcg_streaming_header_##cname##_show)
+
+#define identity_conv(x) (x)
+
+UVCG_STREAMING_HEADER_ATTR(bm_info, bmInfo, identity_conv);
+UVCG_STREAMING_HEADER_ATTR(b_terminal_link, bTerminalLink, identity_conv);
+UVCG_STREAMING_HEADER_ATTR(b_still_capture_method, bStillCaptureMethod,
+			   identity_conv);
+UVCG_STREAMING_HEADER_ATTR(b_trigger_support, bTriggerSupport, identity_conv);
+UVCG_STREAMING_HEADER_ATTR(b_trigger_usage, bTriggerUsage, identity_conv);
+
+#undef identity_conv
+
+#undef UVCG_STREAMING_HEADER_ATTR
+
+static struct configfs_attribute *uvcg_streaming_header_attrs[] = {
+	&uvcg_streaming_header_bm_info.attr,
+	&uvcg_streaming_header_b_terminal_link.attr,
+	&uvcg_streaming_header_b_still_capture_method.attr,
+	&uvcg_streaming_header_b_trigger_support.attr,
+	&uvcg_streaming_header_b_trigger_usage.attr,
+	NULL,
+};
+
+struct config_item_type uvcg_streaming_header_type = {
+	.ct_item_ops	= &uvcg_streaming_header_item_ops,
+	.ct_attrs	= uvcg_streaming_header_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_item
+*uvcg_streaming_header_make(struct config_group *group, const char *name)
+{
+	struct uvcg_streaming_header *h;
+
+	h = kzalloc(sizeof(*h), GFP_KERNEL);
+	if (!h)
+		return ERR_CAST(h);
+
+	INIT_LIST_HEAD(&h->formats);
+	h->desc.bDescriptorType		= USB_DT_CS_INTERFACE;
+	h->desc.bDescriptorSubType	= UVC_VS_INPUT_HEADER;
+	h->desc.bTerminalLink		= 3;
+	h->desc.bControlSize		= UVCG_STREAMING_CONTROL_SIZE;
+
+	config_item_init_type_name(&h->item, name, &uvcg_streaming_header_type);
+
+	return &h->item;
+}
+
+void uvcg_streaming_header_drop(struct config_group *group,
+			      struct config_item *item)
+{
+	struct uvcg_streaming_header *h = to_uvcg_streaming_header(item);
+
+	kfree(h);
+}
+
+/* streaming/header */
+static struct uvcg_streaming_header_grp {
+	struct config_group	group;
+} uvcg_streaming_header_grp;
+
+static struct configfs_group_operations uvcg_streaming_header_grp_ops = {
+	.make_item		= uvcg_streaming_header_make,
+	.drop_item		= uvcg_streaming_header_drop,
+};
+
+static struct config_item_type uvcg_streaming_header_grp_type = {
+	.ct_group_ops	= &uvcg_streaming_header_grp_ops,
+	.ct_owner	= THIS_MODULE,
+};
+
+/* streaming/<mode>/<format>/<NAME> */
+struct uvcg_frame {
+	struct {
+		u8	b_length;
+		u8	b_descriptor_type;
+		u8	b_descriptor_subtype;
+		u8	b_frame_index;
+		u8	bm_capabilities;
+		u16	w_width;
+		u16	w_height;
+		u32	dw_min_bit_rate;
+		u32	dw_max_bit_rate;
+		u32	dw_max_video_frame_buffer_size;
+		u32	dw_default_frame_interval;
+		u8	b_frame_interval_type;
+	} __attribute__((packed)) frame;
+	u32 *dw_frame_interval;
+	enum uvcg_format_type	fmt_type;
+	struct config_item	item;
+};
+
+struct uvcg_frame *to_uvcg_frame(struct config_item *item)
+{
+	return container_of(item, struct uvcg_frame, item);
+}
+
+CONFIGFS_ATTR_STRUCT(uvcg_frame);
+CONFIGFS_ATTR_OPS(uvcg_frame);
+
+static struct configfs_item_operations uvcg_frame_item_ops = {
+	.show_attribute		= uvcg_frame_attr_show,
+	.store_attribute	= uvcg_frame_attr_store,
+};
+
+#define UVCG_FRAME_ATTR(cname, aname, conv, str2u, uxx, vnoc, limit)	\
+static ssize_t uvcg_frame_##cname##_show(struct uvcg_frame *f, char *page)\
+{									\
+	struct f_uvc_opts *opts;					\
+	struct config_item *opts_item;					\
+	struct mutex *su_mutex = &f->item.ci_group->cg_subsys->su_mutex;\
+	int result;							\
+									\
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
+									\
+	opts_item = f->item.ci_parent->ci_parent->ci_parent->ci_parent;	\
+	opts = to_f_uvc_opts(opts_item);				\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%d\n", conv(f->frame.cname));		\
+	mutex_unlock(&opts->lock);					\
+									\
+	mutex_unlock(su_mutex);						\
+	return result;							\
+}									\
+									\
+static ssize_t  uvcg_frame_##cname##_store(struct uvcg_frame *f,	\
+					   const char *page, size_t len)\
+{									\
+	struct f_uvc_opts *opts;					\
+	struct config_item *opts_item;					\
+	struct uvcg_format *fmt;					\
+	struct mutex *su_mutex = &f->item.ci_group->cg_subsys->su_mutex;\
+	int ret;							\
+	uxx num;							\
+									\
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
+									\
+	opts_item = f->item.ci_parent->ci_parent->ci_parent->ci_parent;	\
+	opts = to_f_uvc_opts(opts_item);				\
+	fmt = to_uvcg_format(f->item.ci_parent);			\
+									\
+	mutex_lock(&opts->lock);					\
+	if (fmt->linked || opts->refcnt) {				\
+		ret = -EBUSY;						\
+		goto end;						\
+	}								\
+									\
+	ret = str2u(page, 0, &num);					\
+	if (ret)							\
+		goto end;						\
+									\
+	if (num > limit) {						\
+		ret = -EINVAL;						\
+		goto end;						\
+	}								\
+	f->frame.cname = vnoc(num);					\
+	ret = len;							\
+end:									\
+	mutex_unlock(&opts->lock);					\
+	mutex_unlock(su_mutex);						\
+	return ret;							\
+}									\
+									\
+static struct uvcg_frame_attribute					\
+	uvcg_frame_##cname =						\
+	__CONFIGFS_ATTR(aname, S_IRUGO | S_IWUSR,			\
+			uvcg_frame_##cname##_show,			\
+			uvcg_frame_##cname##_store)
+
+#define identity_conv(x) (x)
+
+UVCG_FRAME_ATTR(bm_capabilities, bmCapabilities, identity_conv, kstrtou8, u8,
+		identity_conv, 0xFF);
+UVCG_FRAME_ATTR(w_width, wWidth, le16_to_cpu, kstrtou16, u16, cpu_to_le16,
+		0xFFFF);
+UVCG_FRAME_ATTR(w_height, wHeight, le16_to_cpu, kstrtou16, u16, cpu_to_le16,
+		0xFFFF);
+UVCG_FRAME_ATTR(dw_min_bit_rate, dwMinBitRate, le32_to_cpu, kstrtou32, u32,
+		cpu_to_le32, 0xFFFFFFFF);
+UVCG_FRAME_ATTR(dw_max_bit_rate, dwMaxBitRate, le32_to_cpu, kstrtou32, u32,
+		cpu_to_le32, 0xFFFFFFFF);
+UVCG_FRAME_ATTR(dw_max_video_frame_buffer_size, dwMaxVideoFrameBufferSize,
+		le32_to_cpu, kstrtou32, u32, cpu_to_le32, 0xFFFFFFFF);
+UVCG_FRAME_ATTR(dw_default_frame_interval, dwDefaultFrameInterval,
+		le32_to_cpu, kstrtou32, u32, cpu_to_le32, 0xFFFFFFFF);
+
+#undef identity_conv
+
+#undef UVCG_FRAME_ATTR
+
+static ssize_t uvcg_frame_dw_frame_interval_show(struct uvcg_frame *frm,
+						 char *page)
+{
+	struct f_uvc_opts *opts;
+	struct config_item *opts_item;
+	struct mutex *su_mutex = &frm->item.ci_group->cg_subsys->su_mutex;
+	int result, i;
+	char *pg = page;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	opts_item = frm->item.ci_parent->ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+	for (result = 0, i = 0; i < frm->frame.b_frame_interval_type; ++i) {
+		result += sprintf(pg, "%d\n",
+				  le32_to_cpu(frm->dw_frame_interval[i]));
+		pg = page + result;
+	}
+	mutex_unlock(&opts->lock);
+
+	mutex_unlock(su_mutex);
+	return result;
+}
+
+static inline int __uvcg_count_frm_intrv(char *buf, void *priv)
+{
+	++*((int *)priv);
+	return 0;
+}
+
+static inline int __uvcg_fill_frm_intrv(char *buf, void *priv)
+{
+	u32 num, **interv;
+	int ret;
+
+	ret = kstrtou32(buf, 0, &num);
+	if (ret)
+		return ret;
+	if (num > 0xFFFFFFFF)
+		return -EINVAL;
+
+	interv = priv;
+	**interv = cpu_to_le32(num);
+	++*interv;
+
+	return 0;
+}
+
+static int __uvcg_iter_frm_intrv(const char *page, size_t len,
+				 int (*fun)(char *, void *), void *priv)
+{
+	/* sign, base 2 representation, newline, terminator */
+	char buf[1 + sizeof(u32) * 8 + 1 + 1];
+	const char *pg = page;
+	int i, ret;
+
+	if (!fun)
+		return -EINVAL;
+
+	while (pg - page < len) {
+		i = 0;
+		while (i < sizeof(buf) && (pg - page < len) &&
+				*pg != '\0' && *pg != '\n')
+			buf[i++] = *pg++;
+		if (i == sizeof(buf))
+			return -EINVAL;
+		while ((pg - page < len) && (*pg == '\0' || *pg == '\n'))
+			++pg;
+		buf[i] = '\0';
+		ret = fun(buf, priv);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static ssize_t uvcg_frame_dw_frame_interval_store(struct uvcg_frame *ch,
+						  const char *page, size_t len)
+{
+	struct f_uvc_opts *opts;
+	struct config_item *opts_item;
+	struct uvcg_format *fmt;
+	struct mutex *su_mutex = &ch->item.ci_group->cg_subsys->su_mutex;
+	int ret = 0, n = 0;
+	u32 *frm_intrv, *tmp;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	opts_item = ch->item.ci_parent->ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+	fmt = to_uvcg_format(ch->item.ci_parent);
+
+	mutex_lock(&opts->lock);
+	if (fmt->linked || opts->refcnt) {
+		ret = -EBUSY;
+		goto end;
+	}
+
+	ret = __uvcg_iter_frm_intrv(page, len, __uvcg_count_frm_intrv, &n);
+	if (ret)
+		goto end;
+
+	tmp = frm_intrv = kcalloc(n, sizeof(u32), GFP_KERNEL);
+	if (!frm_intrv) {
+		ret = -ENOMEM;
+		goto end;
+	}
+
+	ret = __uvcg_iter_frm_intrv(page, len, __uvcg_fill_frm_intrv, &tmp);
+	if (ret) {
+		kfree(frm_intrv);
+		goto end;
+	}
+
+	kfree(ch->dw_frame_interval);
+	ch->dw_frame_interval = frm_intrv;
+	ch->frame.b_frame_interval_type = n;
+	ret = len;
+
+end:
+	mutex_unlock(&opts->lock);
+	mutex_unlock(su_mutex);
+	return ret;
+}
+
+static struct uvcg_frame_attribute
+	uvcg_frame_dw_frame_interval =
+	__CONFIGFS_ATTR(dwFrameInterval, S_IRUGO | S_IWUSR,
+			uvcg_frame_dw_frame_interval_show,
+			uvcg_frame_dw_frame_interval_store);
+
+static struct configfs_attribute *uvcg_frame_attrs[] = {
+	&uvcg_frame_bm_capabilities.attr,
+	&uvcg_frame_w_width.attr,
+	&uvcg_frame_w_height.attr,
+	&uvcg_frame_dw_min_bit_rate.attr,
+	&uvcg_frame_dw_max_bit_rate.attr,
+	&uvcg_frame_dw_max_video_frame_buffer_size.attr,
+	&uvcg_frame_dw_default_frame_interval.attr,
+	&uvcg_frame_dw_frame_interval.attr,
+	NULL,
+};
+
+struct config_item_type uvcg_frame_type = {
+	.ct_item_ops	= &uvcg_frame_item_ops,
+	.ct_attrs	= uvcg_frame_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_item *uvcg_frame_make(struct config_group *group,
+					   const char *name)
+{
+	struct uvcg_frame *h;
+	struct uvcg_format *fmt;
+	struct f_uvc_opts *opts;
+	struct config_item *opts_item;
+
+	h = kzalloc(sizeof(*h), GFP_KERNEL);
+	if (!h)
+		return ERR_CAST(h);
+
+	h->frame.b_descriptor_type		= USB_DT_CS_INTERFACE;
+	h->frame.b_frame_index			= 1;
+	h->frame.w_width			= cpu_to_le16(640);
+	h->frame.w_height			= cpu_to_le16(360);
+	h->frame.dw_min_bit_rate		= cpu_to_le32(18432000);
+	h->frame.dw_max_bit_rate		= cpu_to_le32(55296000);
+	h->frame.dw_max_video_frame_buffer_size	= cpu_to_le32(460800);
+	h->frame.dw_default_frame_interval	= cpu_to_le32(666666);
+
+	opts_item = group->cg_item.ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+	fmt = to_uvcg_format(&group->cg_item);
+	if (fmt->type == UVCG_UNCOMPRESSED) {
+		h->frame.b_descriptor_subtype = UVC_VS_FRAME_UNCOMPRESSED;
+		h->fmt_type = UVCG_UNCOMPRESSED;
+	} else if (fmt->type == UVCG_MJPEG) {
+		h->frame.b_descriptor_subtype = UVC_VS_FRAME_MJPEG;
+		h->fmt_type = UVCG_MJPEG;
+	} else {
+		mutex_unlock(&opts->lock);
+		return ERR_PTR(-EINVAL);
+	}
+	++fmt->num_frames;
+	mutex_unlock(&opts->lock);
+
+	config_item_init_type_name(&h->item, name, &uvcg_frame_type);
+
+	return &h->item;
+}
+
+void uvcg_frame_drop(struct config_group *group, struct config_item *item)
+{
+	struct uvcg_frame *h = to_uvcg_frame(item);
+	struct uvcg_format *fmt;
+	struct f_uvc_opts *opts;
+	struct config_item *opts_item;
+
+	opts_item = group->cg_item.ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+	fmt = to_uvcg_format(&group->cg_item);
+	--fmt->num_frames;
+	kfree(h);
+	mutex_unlock(&opts->lock);
+}
+
+/* streaming/uncompressed/<NAME> */
+struct uvcg_uncompressed {
+	struct uvcg_format		fmt;
+	struct uvc_format_uncompressed	desc;
+};
+
+struct uvcg_uncompressed *to_uvcg_uncompressed(struct config_item *item)
+{
+	return container_of(
+		container_of(to_config_group(item), struct uvcg_format, group),
+		struct uvcg_uncompressed, fmt);
+}
+
+CONFIGFS_ATTR_STRUCT(uvcg_uncompressed);
+CONFIGFS_ATTR_OPS(uvcg_uncompressed);
+
+static struct configfs_item_operations uvcg_uncompressed_item_ops = {
+	.show_attribute		= uvcg_uncompressed_attr_show,
+	.store_attribute	= uvcg_uncompressed_attr_store,
+};
+
+static struct configfs_group_operations uvcg_uncompressed_group_ops = {
+	.make_item		= uvcg_frame_make,
+	.drop_item		= uvcg_frame_drop,
+};
+
+static ssize_t uvcg_uncompressed_guid_format_show(struct uvcg_uncompressed *ch,
+							char *page)
+{
+	struct f_uvc_opts *opts;
+	struct config_item *opts_item;
+	struct mutex *su_mutex = &ch->fmt.group.cg_subsys->su_mutex;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	opts_item = ch->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+	memcpy(page, ch->desc.guidFormat, sizeof(ch->desc.guidFormat));
+	mutex_unlock(&opts->lock);
+
+	mutex_unlock(su_mutex);
+
+	return sizeof(ch->desc.guidFormat);
+}
+
+static ssize_t uvcg_uncompressed_guid_format_store(struct uvcg_uncompressed *ch,
+						   const char *page, size_t len)
+{
+	struct f_uvc_opts *opts;
+	struct config_item *opts_item;
+	struct mutex *su_mutex = &ch->fmt.group.cg_subsys->su_mutex;
+	int ret;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	opts_item = ch->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;
+	opts = to_f_uvc_opts(opts_item);
+
+	mutex_lock(&opts->lock);
+	if (ch->fmt.linked || opts->refcnt) {
+		ret = -EBUSY;
+		goto end;
+	}
+
+	memcpy(ch->desc.guidFormat, page,
+	       min(sizeof(ch->desc.guidFormat), len));
+	ret = sizeof(ch->desc.guidFormat);
+
+end:
+	mutex_unlock(&opts->lock);
+	mutex_unlock(su_mutex);
+	return ret;
+}
+
+static struct uvcg_uncompressed_attribute uvcg_uncompressed_guid_format =
+	__CONFIGFS_ATTR(guidFormat, S_IRUGO | S_IWUSR,
+			uvcg_uncompressed_guid_format_show,
+			uvcg_uncompressed_guid_format_store);
+
+
+#define UVCG_UNCOMPRESSED_ATTR_RO(cname, aname, conv)			\
+static ssize_t uvcg_uncompressed_##cname##_show(			\
+	struct uvcg_uncompressed *u, char *page)			\
+{									\
+	struct f_uvc_opts *opts;					\
+	struct config_item *opts_item;					\
+	struct mutex *su_mutex = &u->fmt.group.cg_subsys->su_mutex;	\
+	int result;							\
+									\
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
+									\
+	opts_item = u->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;\
+	opts = to_f_uvc_opts(opts_item);				\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%d\n", conv(u->desc.aname));		\
+	mutex_unlock(&opts->lock);					\
+									\
+	mutex_unlock(su_mutex);						\
+	return result;							\
+}									\
+									\
+static struct uvcg_uncompressed_attribute				\
+	uvcg_uncompressed_##cname =					\
+	__CONFIGFS_ATTR_RO(aname, uvcg_uncompressed_##cname##_show)
+
+#define UVCG_UNCOMPRESSED_ATTR(cname, aname, conv)			\
+static ssize_t uvcg_uncompressed_##cname##_show(			\
+	struct uvcg_uncompressed *u, char *page)			\
+{									\
+	struct f_uvc_opts *opts;					\
+	struct config_item *opts_item;					\
+	struct mutex *su_mutex = &u->fmt.group.cg_subsys->su_mutex;	\
+	int result;							\
+									\
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
+									\
+	opts_item = u->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;\
+	opts = to_f_uvc_opts(opts_item);				\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%d\n", conv(u->desc.aname));		\
+	mutex_unlock(&opts->lock);					\
+									\
+	mutex_unlock(su_mutex);						\
+	return result;							\
+}									\
+									\
+static ssize_t								\
+uvcg_uncompressed_##cname##_store(struct uvcg_uncompressed *u,		\
+				    const char *page, size_t len)	\
+{									\
+	struct f_uvc_opts *opts;					\
+	struct config_item *opts_item;					\
+	struct mutex *su_mutex = &u->fmt.group.cg_subsys->su_mutex;	\
+	int ret;							\
+	u8 num;								\
+									\
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
+									\
+	opts_item = u->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;\
+	opts = to_f_uvc_opts(opts_item);				\
+									\
+	mutex_lock(&opts->lock);					\
+	if (u->fmt.linked || opts->refcnt) {				\
+		ret = -EBUSY;						\
+		goto end;						\
+	}								\
+									\
+	ret = kstrtou8(page, 0, &num);					\
+	if (ret)							\
+		goto end;						\
+									\
+	if (num > 255) {						\
+		ret = -EINVAL;						\
+		goto end;						\
+	}								\
+	u->desc.aname = num;						\
+	ret = len;							\
+end:									\
+	mutex_unlock(&opts->lock);					\
+	mutex_unlock(su_mutex);						\
+	return ret;							\
+}									\
+									\
+static struct uvcg_uncompressed_attribute				\
+	uvcg_uncompressed_##cname =					\
+	__CONFIGFS_ATTR(aname, S_IRUGO | S_IWUSR,			\
+			uvcg_uncompressed_##cname##_show,		\
+			uvcg_uncompressed_##cname##_store)
+
+#define identity_conv(x) (x)
+
+UVCG_UNCOMPRESSED_ATTR(b_bits_per_pixel, bBitsPerPixel, identity_conv);
+UVCG_UNCOMPRESSED_ATTR(b_default_frame_index, bDefaultFrameIndex,
+		       identity_conv);
+UVCG_UNCOMPRESSED_ATTR_RO(b_aspect_ratio_x, bAspectRatioX, identity_conv);
+UVCG_UNCOMPRESSED_ATTR_RO(b_aspect_ratio_y, bAspectRatioY, identity_conv);
+UVCG_UNCOMPRESSED_ATTR_RO(bm_interface_flags, bmInterfaceFlags, identity_conv);
+
+#undef identity_conv
+
+#undef UVCG_UNCOMPRESSED_ATTR
+#undef UVCG_UNCOMPRESSED_ATTR_RO
+
+static inline ssize_t
+uvcg_uncompressed_bma_controls_show(struct uvcg_uncompressed *unc, char *page)
+{
+	return uvcg_format_bma_controls_show(&unc->fmt, page);
+}
+
+static inline ssize_t
+uvcg_uncompressed_bma_controls_store(struct uvcg_uncompressed *ch,
+				     const char *page, size_t len)
+{
+	return uvcg_format_bma_controls_store(&ch->fmt, page, len);
+}
+
+static struct uvcg_uncompressed_attribute uvcg_uncompressed_bma_controls =
+	__CONFIGFS_ATTR(bmaControls, S_IRUGO | S_IWUSR,
+			uvcg_uncompressed_bma_controls_show,
+			uvcg_uncompressed_bma_controls_store);
+
+static struct configfs_attribute *uvcg_uncompressed_attrs[] = {
+	&uvcg_uncompressed_guid_format.attr,
+	&uvcg_uncompressed_b_bits_per_pixel.attr,
+	&uvcg_uncompressed_b_default_frame_index.attr,
+	&uvcg_uncompressed_b_aspect_ratio_x.attr,
+	&uvcg_uncompressed_b_aspect_ratio_y.attr,
+	&uvcg_uncompressed_bm_interface_flags.attr,
+	&uvcg_uncompressed_bma_controls.attr,
+	NULL,
+};
+
+struct config_item_type uvcg_uncompressed_type = {
+	.ct_item_ops	= &uvcg_uncompressed_item_ops,
+	.ct_group_ops	= &uvcg_uncompressed_group_ops,
+	.ct_attrs	= uvcg_uncompressed_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_group *uvcg_uncompressed_make(struct config_group *group,
+						   const char *name)
+{
+	static char guid[] = {
+		'Y',  'U',  'Y',  '2', 0x00, 0x00, 0x10, 0x00,
+		 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71
+	};
+	struct uvcg_uncompressed *h;
+
+	h = kzalloc(sizeof(*h), GFP_KERNEL);
+	if (!h)
+		return ERR_CAST(h);
+
+	h->desc.bLength			= UVC_DT_FORMAT_UNCOMPRESSED_SIZE;
+	h->desc.bDescriptorType		= USB_DT_CS_INTERFACE;
+	h->desc.bDescriptorSubType	= UVC_VS_FORMAT_UNCOMPRESSED;
+	memcpy(h->desc.guidFormat, guid, sizeof(guid));
+	h->desc.bBitsPerPixel		= 16;
+	h->desc.bDefaultFrameIndex	= 1;
+	h->desc.bAspectRatioX		= 0;
+	h->desc.bAspectRatioY		= 0;
+	h->desc.bmInterfaceFlags	= 0;
+	h->desc.bCopyProtect		= 0;
+
+	h->fmt.type = UVCG_UNCOMPRESSED;
+	config_group_init_type_name(&h->fmt.group, name,
+				    &uvcg_uncompressed_type);
+
+	return &h->fmt.group;
+}
+
+void uvcg_uncompressed_drop(struct config_group *group,
+			    struct config_item *item)
+{
+	struct uvcg_uncompressed *h = to_uvcg_uncompressed(item);
+
+	kfree(h);
+}
+
+static struct configfs_group_operations uvcg_uncompressed_grp_ops = {
+	.make_group		= uvcg_uncompressed_make,
+	.drop_item		= uvcg_uncompressed_drop,
+};
+
+static struct config_item_type uvcg_uncompressed_grp_type = {
+	.ct_group_ops	= &uvcg_uncompressed_grp_ops,
+	.ct_owner	= THIS_MODULE,
+};
+
+/* streaming/mjpeg/<NAME> */
+struct uvcg_mjpeg {
+	struct uvcg_format		fmt;
+	struct uvc_format_mjpeg		desc;
+};
+
+struct uvcg_mjpeg *to_uvcg_mjpeg(struct config_item *item)
+{
+	return container_of(
+		container_of(to_config_group(item), struct uvcg_format, group),
+		struct uvcg_mjpeg, fmt);
+}
+
+CONFIGFS_ATTR_STRUCT(uvcg_mjpeg);
+CONFIGFS_ATTR_OPS(uvcg_mjpeg);
+
+static struct configfs_item_operations uvcg_mjpeg_item_ops = {
+	.show_attribute		= uvcg_mjpeg_attr_show,
+	.store_attribute	= uvcg_mjpeg_attr_store,
+};
+
+static struct configfs_group_operations uvcg_mjpeg_group_ops = {
+	.make_item		= uvcg_frame_make,
+	.drop_item		= uvcg_frame_drop,
+};
+
+#define UVCG_MJPEG_ATTR_RO(cname, aname, conv)				\
+static ssize_t uvcg_mjpeg_##cname##_show(struct uvcg_mjpeg *u, char *page)\
+{									\
+	struct f_uvc_opts *opts;					\
+	struct config_item *opts_item;					\
+	struct mutex *su_mutex = &u->fmt.group.cg_subsys->su_mutex;	\
+	int result;							\
+									\
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
+									\
+	opts_item = u->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;\
+	opts = to_f_uvc_opts(opts_item);				\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%d\n", conv(u->desc.aname));		\
+	mutex_unlock(&opts->lock);					\
+									\
+	mutex_unlock(su_mutex);						\
+	return result;							\
+}									\
+									\
+static struct uvcg_mjpeg_attribute					\
+	uvcg_mjpeg_##cname =						\
+	__CONFIGFS_ATTR_RO(aname, uvcg_mjpeg_##cname##_show)
+
+#define UVCG_MJPEG_ATTR(cname, aname, conv)				\
+static ssize_t uvcg_mjpeg_##cname##_show(struct uvcg_mjpeg *u, char *page)\
+{									\
+	struct f_uvc_opts *opts;					\
+	struct config_item *opts_item;					\
+	struct mutex *su_mutex = &u->fmt.group.cg_subsys->su_mutex;	\
+	int result;							\
+									\
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
+									\
+	opts_item = u->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;\
+	opts = to_f_uvc_opts(opts_item);				\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%d\n", conv(u->desc.aname));		\
+	mutex_unlock(&opts->lock);					\
+									\
+	mutex_unlock(su_mutex);						\
+	return result;							\
+}									\
+									\
+static ssize_t								\
+uvcg_mjpeg_##cname##_store(struct uvcg_mjpeg *u,			\
+			   const char *page, size_t len)		\
+{									\
+	struct f_uvc_opts *opts;					\
+	struct config_item *opts_item;					\
+	struct mutex *su_mutex = &u->fmt.group.cg_subsys->su_mutex;	\
+	int ret;							\
+	u8 num;								\
+									\
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
+									\
+	opts_item = u->fmt.group.cg_item.ci_parent->ci_parent->ci_parent;\
+	opts = to_f_uvc_opts(opts_item);				\
+									\
+	mutex_lock(&opts->lock);					\
+	if (u->fmt.linked || opts->refcnt) {				\
+		ret = -EBUSY;						\
+		goto end;						\
+	}								\
+									\
+	ret = kstrtou8(page, 0, &num);					\
+	if (ret)							\
+		goto end;						\
+									\
+	if (num > 255) {						\
+		ret = -EINVAL;						\
+		goto end;						\
+	}								\
+	u->desc.aname = num;						\
+	ret = len;							\
+end:									\
+	mutex_unlock(&opts->lock);					\
+	mutex_unlock(su_mutex);						\
+	return ret;							\
+}									\
+									\
+static struct uvcg_mjpeg_attribute					\
+	uvcg_mjpeg_##cname =						\
+	__CONFIGFS_ATTR(aname, S_IRUGO | S_IWUSR,			\
+			uvcg_mjpeg_##cname##_show,			\
+			uvcg_mjpeg_##cname##_store)
+
+#define identity_conv(x) (x)
+
+UVCG_MJPEG_ATTR(b_default_frame_index, bDefaultFrameIndex,
+		       identity_conv);
+UVCG_MJPEG_ATTR_RO(bm_flags, bmFlags, identity_conv);
+UVCG_MJPEG_ATTR_RO(b_aspect_ratio_x, bAspectRatioX, identity_conv);
+UVCG_MJPEG_ATTR_RO(b_aspect_ratio_y, bAspectRatioY, identity_conv);
+UVCG_MJPEG_ATTR_RO(bm_interface_flags, bmInterfaceFlags, identity_conv);
+
+#undef identity_conv
+
+#undef UVCG_MJPEG_ATTR
+#undef UVCG_MJPEG_ATTR_RO
+
+static inline ssize_t
+uvcg_mjpeg_bma_controls_show(struct uvcg_mjpeg *unc, char *page)
+{
+	return uvcg_format_bma_controls_show(&unc->fmt, page);
+}
+
+static inline ssize_t
+uvcg_mjpeg_bma_controls_store(struct uvcg_mjpeg *ch,
+				     const char *page, size_t len)
+{
+	return uvcg_format_bma_controls_store(&ch->fmt, page, len);
+}
+
+static struct uvcg_mjpeg_attribute uvcg_mjpeg_bma_controls =
+	__CONFIGFS_ATTR(bmaControls, S_IRUGO | S_IWUSR,
+			uvcg_mjpeg_bma_controls_show,
+			uvcg_mjpeg_bma_controls_store);
+
+static struct configfs_attribute *uvcg_mjpeg_attrs[] = {
+	&uvcg_mjpeg_b_default_frame_index.attr,
+	&uvcg_mjpeg_bm_flags.attr,
+	&uvcg_mjpeg_b_aspect_ratio_x.attr,
+	&uvcg_mjpeg_b_aspect_ratio_y.attr,
+	&uvcg_mjpeg_bm_interface_flags.attr,
+	&uvcg_mjpeg_bma_controls.attr,
+	NULL,
+};
+
+struct config_item_type uvcg_mjpeg_type = {
+	.ct_item_ops	= &uvcg_mjpeg_item_ops,
+	.ct_group_ops	= &uvcg_mjpeg_group_ops,
+	.ct_attrs	= uvcg_mjpeg_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_group *uvcg_mjpeg_make(struct config_group *group,
+						   const char *name)
+{
+	struct uvcg_mjpeg *h;
+
+	h = kzalloc(sizeof(*h), GFP_KERNEL);
+	if (!h)
+		return ERR_CAST(h);
+
+	h->desc.bLength			= UVC_DT_FORMAT_MJPEG_SIZE;
+	h->desc.bDescriptorType		= USB_DT_CS_INTERFACE;
+	h->desc.bDescriptorSubType	= UVC_VS_FORMAT_MJPEG;
+	h->desc.bDefaultFrameIndex	= 1;
+	h->desc.bAspectRatioX		= 0;
+	h->desc.bAspectRatioY		= 0;
+	h->desc.bmInterfaceFlags	= 0;
+	h->desc.bCopyProtect		= 0;
+
+	h->fmt.type = UVCG_MJPEG;
+	config_group_init_type_name(&h->fmt.group, name,
+				    &uvcg_mjpeg_type);
+
+	return &h->fmt.group;
+}
+
+void uvcg_mjpeg_drop(struct config_group *group,
+			    struct config_item *item)
+{
+	struct uvcg_mjpeg *h = to_uvcg_mjpeg(item);
+
+	kfree(h);
+}
+
+static struct configfs_group_operations uvcg_mjpeg_grp_ops = {
+	.make_group		= uvcg_mjpeg_make,
+	.drop_item		= uvcg_mjpeg_drop,
+};
+
+static struct config_item_type uvcg_mjpeg_grp_type = {
+	.ct_group_ops	= &uvcg_mjpeg_grp_ops,
+	.ct_owner	= THIS_MODULE,
+};
+
+/* streaming/color_matching/default */
+static struct uvcg_default_color_matching {
+	struct config_group	group;
+} uvcg_default_color_matching;
+
+static inline struct uvcg_default_color_matching
+*to_uvcg_default_color_matching(struct config_item *item)
+{
+	return container_of(to_config_group(item),
+			    struct uvcg_default_color_matching, group);
+}
+
+CONFIGFS_ATTR_STRUCT(uvcg_default_color_matching);
+CONFIGFS_ATTR_OPS_RO(uvcg_default_color_matching);
+
+static struct configfs_item_operations uvcg_default_color_matching_item_ops = {
+	.show_attribute		= uvcg_default_color_matching_attr_show,
+};
+
+#define UVCG_DEFAULT_COLOR_MATCHING_ATTR(cname, aname, conv)		\
+static ssize_t uvcg_default_color_matching_##cname##_show(		\
+	struct uvcg_default_color_matching *dc, char *page)		\
+{									\
+	struct f_uvc_opts *opts;					\
+	struct config_item *opts_item;					\
+	struct mutex *su_mutex = &dc->group.cg_subsys->su_mutex;	\
+	struct uvc_color_matching_descriptor *cd;			\
+	int result;							\
+									\
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
+									\
+	opts_item = dc->group.cg_item.ci_parent->ci_parent->ci_parent;	\
+	opts = to_f_uvc_opts(opts_item);				\
+	cd = &opts->uvc_color_matching;					\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%d\n", conv(cd->aname));		\
+	mutex_unlock(&opts->lock);					\
+									\
+	mutex_unlock(su_mutex);						\
+	return result;							\
+}									\
+									\
+static struct uvcg_default_color_matching_attribute			\
+	uvcg_default_color_matching_##cname =				\
+	__CONFIGFS_ATTR_RO(aname, uvcg_default_color_matching_##cname##_show)
+
+#define identity_conv(x) (x)
+
+UVCG_DEFAULT_COLOR_MATCHING_ATTR(b_color_primaries, bColorPrimaries,
+				 identity_conv);
+UVCG_DEFAULT_COLOR_MATCHING_ATTR(b_transfer_characteristics,
+				 bTransferCharacteristics, identity_conv);
+UVCG_DEFAULT_COLOR_MATCHING_ATTR(b_matrix_coefficients, bMatrixCoefficients,
+				 identity_conv);
+
+#undef identity_conv
+
+#undef UVCG_DEFAULT_COLOR_MATCHING_ATTR
+
+static struct configfs_attribute *uvcg_default_color_matching_attrs[] = {
+	&uvcg_default_color_matching_b_color_primaries.attr,
+	&uvcg_default_color_matching_b_transfer_characteristics.attr,
+	&uvcg_default_color_matching_b_matrix_coefficients.attr,
+	NULL,
+};
+
+static struct config_item_type uvcg_default_color_matching_type = {
+	.ct_item_ops	= &uvcg_default_color_matching_item_ops,
+	.ct_attrs	= uvcg_default_color_matching_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+/* struct uvcg_color_matching {}; */
+
+static struct config_group *uvcg_color_matching_default_groups[] = {
+	&uvcg_default_color_matching.group,
+	NULL,
+};
+
+/* streaming/color_matching */
+static struct uvcg_color_matching_grp {
+	struct config_group	group;
+} uvcg_color_matching_grp;
+
+static struct config_item_type uvcg_color_matching_grp_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+/* streaming/class/{fs|hs|ss} */
+static struct uvcg_streaming_class {
+	struct config_group	group;
+} uvcg_streaming_class_fs, uvcg_streaming_class_hs, uvcg_streaming_class_ss;
+
+
+static inline struct uvc_descriptor_header
+***__uvcg_get_stream_class_arr(struct config_item *i, struct f_uvc_opts *o)
+{
+	struct uvcg_streaming_class *cl = container_of(to_config_group(i),
+		struct uvcg_streaming_class, group);
+
+	if (cl == &uvcg_streaming_class_fs)
+		return &o->uvc_fs_streaming_cls;
+
+	if (cl == &uvcg_streaming_class_hs)
+		return &o->uvc_hs_streaming_cls;
+
+	if (cl == &uvcg_streaming_class_ss)
+		return &o->uvc_ss_streaming_cls;
+
+	return NULL;
+}
+
+enum uvcg_strm_type {
+	UVCG_HEADER = 0,
+	UVCG_FORMAT,
+	UVCG_FRAME
+};
+
+static int __uvcg_iter_strm_cls(void *priv1, void *priv2, void *priv3,
+	int (*fun)(void *, void *, void *, int, enum uvcg_strm_type type))
+{
+	struct uvcg_streaming_header *h = priv1;
+	struct uvcg_format_ptr *f;
+	struct config_group *grp;
+	struct config_item *item;
+	struct uvcg_frame *frm;
+	int ret, i, j;
+
+	if (!fun)
+		return -EINVAL;
+
+	i = j = 0;
+	ret = fun(h, priv2, priv3, 0, UVCG_HEADER);
+	if (ret)
+		return ret;
+	list_for_each_entry(f, &h->formats, entry) {
+		ret = fun(f->fmt, priv2, priv3, i++, UVCG_FORMAT);
+		if (ret)
+			return ret;
+		grp = &f->fmt->group;
+		list_for_each_entry(item, &grp->cg_children, ci_entry) {
+			frm = to_uvcg_frame(item);
+			ret = fun(frm, priv2, priv3, j++, UVCG_FRAME);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return ret;
+}
+
+static int __uvcg_cnt_strm(void *priv1, void *priv2, void *priv3, int n,
+			   enum uvcg_strm_type type)
+{
+	size_t *size = priv2;
+	size_t *count = priv3;
+
+	switch (type) {
+	case UVCG_HEADER: {
+		struct uvcg_streaming_header *h = priv1;
+
+		*size += sizeof(h->desc);
+		/* bmaControls */
+		*size += h->num_fmt * UVCG_STREAMING_CONTROL_SIZE;
+	}
+	break;
+	case UVCG_FORMAT: {
+		struct uvcg_format *fmt = priv1;
+
+		if (fmt->type == UVCG_UNCOMPRESSED) {
+			struct uvcg_uncompressed *u =
+				container_of(fmt, struct uvcg_uncompressed,
+					     fmt);
+
+			*size += sizeof(u->desc);
+		} else if (fmt->type == UVCG_MJPEG) {
+			struct uvcg_mjpeg *m =
+				container_of(fmt, struct uvcg_mjpeg, fmt);
+
+			*size += sizeof(m->desc);
+		} else {
+			return -EINVAL;
+		}
+	}
+	break;
+	case UVCG_FRAME: {
+		struct uvcg_frame *frm = priv1;
+		int sz = sizeof(frm->dw_frame_interval);
+
+		*size += sizeof(frm->frame);
+		*size += frm->frame.b_frame_interval_type * sz;
+	}
+	break;
+	}
+
+	++*count;
+
+	return 0;
+}
+
+static int __uvcg_fill_strm(void *priv1, void *priv2, void *priv3, int n,
+			    enum uvcg_strm_type type)
+{
+	void **dest = priv2;
+	struct uvc_descriptor_header ***array = priv3;
+	size_t sz;
+
+	**array = *dest;
+	++*array;
+
+	switch (type) {
+	case UVCG_HEADER: {
+		struct uvc_input_header_descriptor *ihdr = *dest;
+		struct uvcg_streaming_header *h = priv1;
+		struct uvcg_format_ptr *f;
+
+		memcpy(*dest, &h->desc, sizeof(h->desc));
+		*dest += sizeof(h->desc);
+		sz = UVCG_STREAMING_CONTROL_SIZE;
+		list_for_each_entry(f, &h->formats, entry) {
+			memcpy(*dest, f->fmt->bmaControls, sz);
+			*dest += sz;
+		}
+		ihdr->bLength = sizeof(h->desc) + h->num_fmt * sz;
+		ihdr->bNumFormats = h->num_fmt;
+	}
+	break;
+	case UVCG_FORMAT: {
+		struct uvcg_format *fmt = priv1;
+
+		if (fmt->type == UVCG_UNCOMPRESSED) {
+			struct uvc_format_uncompressed *unc = *dest;
+			struct uvcg_uncompressed *u =
+				container_of(fmt, struct uvcg_uncompressed,
+					     fmt);
+
+			memcpy(*dest, &u->desc, sizeof(u->desc));
+			*dest += sizeof(u->desc);
+			unc->bNumFrameDescriptors = fmt->num_frames;
+			unc->bFormatIndex = n + 1;
+		} else if (fmt->type == UVCG_MJPEG) {
+			struct uvc_format_mjpeg *mjp = *dest;
+			struct uvcg_mjpeg *m =
+				container_of(fmt, struct uvcg_mjpeg, fmt);
+
+			memcpy(*dest, &m->desc, sizeof(m->desc));
+			*dest += sizeof(m->desc);
+			mjp->bNumFrameDescriptors = fmt->num_frames;
+			mjp->bFormatIndex = n + 1;
+		} else {
+			return -EINVAL;
+		}
+	}
+	break;
+	case UVCG_FRAME: {
+		struct uvcg_frame *frm = priv1;
+		struct uvc_descriptor_header *h = *dest;
+
+		sz = sizeof(frm->frame);
+		memcpy(*dest, &frm->frame, sz);
+		*dest += sz;
+		sz = frm->frame.b_frame_interval_type *
+			sizeof(*frm->dw_frame_interval);
+		memcpy(*dest, frm->dw_frame_interval, sz);
+		*dest += sz;
+		if (frm->fmt_type == UVCG_UNCOMPRESSED)
+			h->bLength = UVC_DT_FRAME_UNCOMPRESSED_SIZE(
+				frm->frame.b_frame_interval_type);
+		else if (frm->fmt_type == UVCG_MJPEG)
+			h->bLength = UVC_DT_FRAME_MJPEG_SIZE(
+				frm->frame.b_frame_interval_type);
+	}
+	break;
+	}
+
+	return 0;
+}
+
+static int uvcg_streaming_class_allow_link(struct config_item *src,
+					   struct config_item *target)
+{
+	struct config_item *streaming, *header;
+	struct f_uvc_opts *opts;
+	struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
+	struct uvc_descriptor_header ***class_array, **cl_arr;
+	struct uvcg_streaming_header *target_hdr;
+	void *data;
+	size_t size = 0, count = 0;
+	int ret = -EINVAL;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	streaming = src->ci_parent->ci_parent;
+	header = config_group_find_item(to_config_group(streaming), "header");
+	if (!header || target->ci_parent != header)
+		goto out;
+
+	opts = to_f_uvc_opts(streaming->ci_parent);
+
+	mutex_lock(&opts->lock);
+
+	class_array = __uvcg_get_stream_class_arr(src, opts);
+	if (!class_array || *class_array || opts->refcnt) {
+		ret = -EBUSY;
+		goto unlock;
+	}
+
+	target_hdr = to_uvcg_streaming_header(target);
+	ret = __uvcg_iter_strm_cls(target_hdr, &size, &count, __uvcg_cnt_strm);
+	if (ret)
+		goto unlock;
+
+	count += 2; /* color_matching, NULL */
+	*class_array = kcalloc(count, sizeof(void *), GFP_KERNEL);
+	if (!*class_array) {
+		ret = PTR_ERR(*class_array);
+		goto unlock;
+	}
+
+	data = kzalloc(size, GFP_KERNEL);
+	if (!data) {
+		kfree(*class_array);
+		*class_array = NULL;
+		ret = PTR_ERR(data);
+		goto unlock;
+	}
+	cl_arr = *class_array;
+	ret = __uvcg_iter_strm_cls(target_hdr, &data, &cl_arr,
+				   __uvcg_fill_strm);
+	if (ret) {
+		kfree(*class_array);
+		*class_array = NULL;
+		kfree(data);
+		goto unlock;
+	}
+	*cl_arr = (struct uvc_descriptor_header *)&opts->uvc_color_matching;
+
+	++target_hdr->linked;
+	ret = 0;
+
+unlock:
+	mutex_unlock(&opts->lock);
+out:
+	mutex_unlock(su_mutex);
+	return ret;
+}
+
+static int uvcg_streaming_class_drop_link(struct config_item *src,
+					  struct config_item *target)
+{
+	struct config_item *streaming, *header;
+	struct f_uvc_opts *opts;
+	struct mutex *su_mutex = &src->ci_group->cg_subsys->su_mutex;
+	struct uvc_descriptor_header ***class_array;
+	struct uvcg_streaming_header *target_hdr;
+	int ret = -EINVAL;
+
+	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
+
+	streaming = src->ci_parent->ci_parent;
+	header = config_group_find_item(to_config_group(streaming), "header");
+	if (!header || target->ci_parent != header)
+		goto out;
+
+	opts = to_f_uvc_opts(streaming->ci_parent);
+
+	mutex_lock(&opts->lock);
+
+	class_array = __uvcg_get_stream_class_arr(src, opts);
+	if (!class_array || !*class_array)
+		goto unlock;
+
+	if (opts->refcnt) {
+		ret = -EBUSY;
+		goto unlock;
+	}
+
+	target_hdr = to_uvcg_streaming_header(target);
+	--target_hdr->linked;
+	kfree(**class_array);
+	kfree(*class_array);
+	*class_array = NULL;
+	ret = 0;
+
+unlock:
+	mutex_unlock(&opts->lock);
+out:
+	mutex_unlock(su_mutex);
+	return ret;
+}
+
+static struct configfs_item_operations uvcg_streaming_class_item_ops = {
+	.allow_link	= uvcg_streaming_class_allow_link,
+	.drop_link	= uvcg_streaming_class_drop_link,
+};
+
+static struct config_item_type uvcg_streaming_class_type = {
+	.ct_item_ops	= &uvcg_streaming_class_item_ops,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_group *uvcg_streaming_class_default_groups[] = {
+	&uvcg_streaming_class_fs.group,
+	&uvcg_streaming_class_hs.group,
+	&uvcg_streaming_class_ss.group,
+	NULL,
+};
+
+/* streaming/class */
+static struct uvcg_streaming_class_grp {
+	struct config_group	group;
+} uvcg_streaming_class_grp;
+
+static struct config_item_type uvcg_streaming_class_grp_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+static struct config_group *uvcg_streaming_default_groups[] = {
+	&uvcg_streaming_header_grp.group,
+	&uvcg_uncompressed_grp.group,
+	&uvcg_mjpeg_grp.group,
+	&uvcg_color_matching_grp.group,
+	&uvcg_streaming_class_grp.group,
+	NULL,
+};
+
+/* streaming */
+static struct uvcg_streaming_grp {
+	struct config_group	group;
+} uvcg_streaming_grp;
+
+static struct config_item_type uvcg_streaming_grp_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+static struct config_group *uvcg_default_groups[] = {
+	&uvcg_control_grp.group,
+	&uvcg_streaming_grp.group,
+	NULL,
+};
+
+static inline struct f_uvc_opts *to_f_uvc_opts(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct f_uvc_opts,
+			    func_inst.group);
+}
+
+CONFIGFS_ATTR_STRUCT(f_uvc_opts);
+CONFIGFS_ATTR_OPS(f_uvc_opts);
+
+static void uvc_attr_release(struct config_item *item)
+{
+	struct f_uvc_opts *opts = to_f_uvc_opts(item);
+
+	usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations uvc_item_ops = {
+	.release		= uvc_attr_release,
+	.show_attribute		= f_uvc_opts_attr_show,
+	.store_attribute	= f_uvc_opts_attr_store,
+};
+
+#define UVCG_OPTS_ATTR(cname, conv, str2u, uxx, vnoc, limit)		\
+static ssize_t f_uvc_opts_##cname##_show(				\
+	struct f_uvc_opts *opts, char *page)				\
+{									\
+	int result;							\
+									\
+	mutex_lock(&opts->lock);					\
+	result = sprintf(page, "%d\n", conv(opts->cname));		\
+	mutex_unlock(&opts->lock);					\
+									\
+	return result;							\
+}									\
+									\
+static ssize_t								\
+f_uvc_opts_##cname##_store(struct f_uvc_opts *opts,			\
+			   const char *page, size_t len)		\
+{									\
+	int ret;							\
+	uxx num;							\
+									\
+	mutex_lock(&opts->lock);					\
+	if (opts->refcnt) {						\
+		ret = -EBUSY;						\
+		goto end;						\
+	}								\
+									\
+	ret = str2u(page, 0, &num);					\
+	if (ret)							\
+		goto end;						\
+									\
+	if (num > limit) {						\
+		ret = -EINVAL;						\
+		goto end;						\
+	}								\
+	opts->cname = vnoc(num);					\
+	ret = len;							\
+end:									\
+	mutex_unlock(&opts->lock);					\
+	return ret;							\
+}									\
+									\
+static struct f_uvc_opts_attribute					\
+	f_uvc_opts_attribute_##cname =					\
+	__CONFIGFS_ATTR(cname, S_IRUGO | S_IWUSR,			\
+			f_uvc_opts_##cname##_show,			\
+			f_uvc_opts_##cname##_store)
+
+#define identity_conv(x) (x)
+
+UVCG_OPTS_ATTR(streaming_interval, identity_conv, kstrtou8, u8, identity_conv,
+	       16);
+UVCG_OPTS_ATTR(streaming_maxpacket, le16_to_cpu, kstrtou16, u16, le16_to_cpu,
+	       3072);
+UVCG_OPTS_ATTR(streaming_maxburst, identity_conv, kstrtou8, u8, identity_conv,
+	       15);
+
+#undef identity_conv
+
+#undef UVCG_OPTS_ATTR
+
+static struct configfs_attribute *uvc_attrs[] = {
+	&f_uvc_opts_attribute_streaming_interval.attr,
+	&f_uvc_opts_attribute_streaming_maxpacket.attr,
+	&f_uvc_opts_attribute_streaming_maxburst.attr,
+	NULL,
+};
+
+static struct config_item_type uvc_func_type = {
+	.ct_item_ops	= &uvc_item_ops,
+	.ct_attrs	= uvc_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static inline void uvcg_init_group(struct config_group *g,
+				   struct config_group **default_groups,
+				   const char *name,
+				   struct config_item_type *type)
+{
+	g->default_groups = default_groups;
+	config_group_init_type_name(g, name, type);
+}
+
+int uvcg_attach_configfs(struct f_uvc_opts *opts)
+{
+	config_group_init_type_name(&uvcg_control_header_grp.group,
+				    "header",
+				    &uvcg_control_header_grp_type);
+	config_group_init_type_name(&uvcg_default_processing.group,
+				    "default",
+				    &uvcg_default_processing_type);
+	uvcg_init_group(&uvcg_processing_grp.group,
+			uvcg_processing_default_groups,
+			"processing",
+			&uvcg_processing_grp_type);
+	config_group_init_type_name(&uvcg_default_camera.group,
+				    "default",
+				    &uvcg_default_camera_type);
+	uvcg_init_group(&uvcg_camera_grp.group,
+			uvcg_camera_default_groups,
+			"camera",
+			&uvcg_camera_grp_type);
+	config_group_init_type_name(&uvcg_default_output.group,
+				    "default",
+				    &uvcg_default_output_type);
+	uvcg_init_group(&uvcg_output_grp.group,
+			uvcg_output_default_groups,
+			"output",
+			&uvcg_output_grp_type);
+	uvcg_init_group(&uvcg_terminal_grp.group,
+			uvcg_terminal_default_groups,
+			"terminal",
+			&uvcg_terminal_grp_type);
+	config_group_init_type_name(&uvcg_control_class_fs.group,
+				    "fs",
+				    &uvcg_control_class_type);
+	config_group_init_type_name(&uvcg_control_class_ss.group,
+				    "ss",
+				    &uvcg_control_class_type);
+	uvcg_init_group(&uvcg_control_class_grp.group,
+			uvcg_control_class_default_groups,
+			"class",
+			&uvcg_control_class_grp_type);
+	uvcg_init_group(&uvcg_control_grp.group,
+			uvcg_control_default_groups,
+			"control",
+			&uvcg_control_grp_type);
+	config_group_init_type_name(&uvcg_streaming_header_grp.group,
+				    "header",
+				    &uvcg_streaming_header_grp_type);
+	config_group_init_type_name(&uvcg_uncompressed_grp.group,
+				    "uncompressed",
+				    &uvcg_uncompressed_grp_type);
+	config_group_init_type_name(&uvcg_mjpeg_grp.group,
+				    "mjpeg",
+				    &uvcg_mjpeg_grp_type);
+	config_group_init_type_name(&uvcg_default_color_matching.group,
+				    "default",
+				    &uvcg_default_color_matching_type);
+	uvcg_init_group(&uvcg_color_matching_grp.group,
+			uvcg_color_matching_default_groups,
+			"color_matching",
+			&uvcg_color_matching_grp_type);
+	config_group_init_type_name(&uvcg_streaming_class_fs.group,
+				    "fs",
+				    &uvcg_streaming_class_type);
+	config_group_init_type_name(&uvcg_streaming_class_hs.group,
+				    "hs",
+				    &uvcg_streaming_class_type);
+	config_group_init_type_name(&uvcg_streaming_class_ss.group,
+				    "ss",
+				    &uvcg_streaming_class_type);
+	uvcg_init_group(&uvcg_streaming_class_grp.group,
+			uvcg_streaming_class_default_groups,
+			"class",
+			&uvcg_streaming_class_grp_type);
+	uvcg_init_group(&uvcg_streaming_grp.group,
+			uvcg_streaming_default_groups,
+			"streaming",
+			&uvcg_streaming_grp_type);
+	uvcg_init_group(&opts->func_inst.group,
+			uvcg_default_groups,
+			"",
+			&uvc_func_type);
+	return 0;
+}

drivers/usb/gadget/function/uvc_configfs.h

+/*
+ * uvc_configfs.h
+ *
+ * Configfs support for the uvc function.
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ *		http://www.samsung.com
+ *
+ * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef UVC_CONFIGFS_H
+#define UVC_CONFIGFS_H
+
+struct f_uvc_opts;
+
+int uvcg_attach_configfs(struct f_uvc_opts *opts);
+
+#endif /* UVC_CONFIGFS_H */