Merge tag 'uvcg-20180925' of git://linuxtv.org/pinchartl/media into testing/next

UVC gadget updates for v4.20

- configfs cleanups, fixes and extensions
- Endianness fixes
- Miscellaneous cleanups

9 files changed, 916 insertions, 710 deletions

diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uvc b/Documentation/ABI/testing/configfs-usb-gadget-uvc
index 9281e2aa38df..809765bd9573 100644
--- a/Documentation/ABI/testing/configfs-usb-gadget-uvc
+++ b/Documentation/ABI/testing/configfs-usb-gadget-uvc
@@ -12,6 +12,10 @@ Date:		Dec 2014
 KernelVersion:	4.0
 Description:	Control descriptors
 
+		All attributes read only:
+		bInterfaceNumber	- USB interface number for this
+					  streaming interface
+
 What:		/config/usb-gadget/gadget/functions/uvc.name/control/class
 Date:		Dec 2014
 KernelVersion:	4.0
@@ -109,6 +113,10 @@ Date:		Dec 2014
 KernelVersion:	4.0
 Description:	Streaming descriptors
 
+		All attributes read only:
+		bInterfaceNumber	- USB interface number for this
+					  streaming interface
+
 What:		/config/usb-gadget/gadget/functions/uvc.name/streaming/class
 Date:		Dec 2014
 KernelVersion:	4.0
@@ -160,6 +168,10 @@ Description:	Specific MJPEG format descriptors
 
 		All attributes read only,
 		except bmaControls and bDefaultFrameIndex:
+		bFormatIndex		- unique id for this format descriptor;
+					only defined after parent header is
+					linked into the streaming class;
+					read-only
 		bmaControls		- this format's data for bmaControls in
 					the streaming header
 		bmInterfaceFlags	- specifies interlace information,
@@ -177,6 +189,10 @@ Date:		Dec 2014
 KernelVersion:	4.0
 Description:	Specific MJPEG frame descriptors
 
+		bFrameIndex		- unique id for this framedescriptor;
+					only defined after parent format is
+					linked into the streaming header;
+					read-only
 		dwFrameInterval		- indicates how frame interval can be
 					programmed; a number of values
 					separated by newline can be specified
@@ -204,6 +220,10 @@ Date:		Dec 2014
 KernelVersion:	4.0
 Description:	Specific uncompressed format descriptors
 
+		bFormatIndex		- unique id for this format descriptor;
+					only defined after parent header is
+					linked into the streaming class;
+					read-only
 		bmaControls		- this format's data for bmaControls in
 					the streaming header
 		bmInterfaceFlags	- specifies interlace information,
@@ -224,6 +244,10 @@ Date:		Dec 2014
 KernelVersion:	4.0
 Description:	Specific uncompressed frame descriptors
 
+		bFrameIndex		- unique id for this framedescriptor;
+					only defined after parent format is
+					linked into the streaming header;
+					read-only
 		dwFrameInterval		- indicates how frame interval can be
 					programmed; a number of values
 					separated by newline can be specified
diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index d8ce7868fe22..8c99392df593 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -197,12 +197,6 @@ static const struct usb_descriptor_header * const uvc_ss_streaming[] = {
 	NULL,
 };
 
-void uvc_set_trace_param(unsigned int trace)
-{
-	uvc_gadget_trace_param = trace;
-}
-EXPORT_SYMBOL(uvc_set_trace_param);
-
 /* --------------------------------------------------------------------------
  * Control requests
  */
@@ -232,13 +226,8 @@ uvc_function_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 	struct v4l2_event v4l2_event;
 	struct uvc_event *uvc_event = (void *)&v4l2_event.u.data;
 
-	/* printk(KERN_INFO "setup request %02x %02x value %04x index %04x %04x\n",
-	 *	ctrl->bRequestType, ctrl->bRequest, le16_to_cpu(ctrl->wValue),
-	 *	le16_to_cpu(ctrl->wIndex), le16_to_cpu(ctrl->wLength));
-	 */
-
 	if ((ctrl->bRequestType & USB_TYPE_MASK) != USB_TYPE_CLASS) {
-		INFO(f->config->cdev, "invalid request type\n");
+		uvcg_info(f, "invalid request type\n");
 		return -EINVAL;
 	}
 
@@ -272,7 +261,7 @@ uvc_function_get_alt(struct usb_function *f, unsigned interface)
 {
 	struct uvc_device *uvc = to_uvc(f);
 
-	INFO(f->config->cdev, "uvc_function_get_alt(%u)\n", interface);
+	uvcg_info(f, "%s(%u)\n", __func__, interface);
 
 	if (interface == uvc->control_intf)
 		return 0;
@@ -291,13 +280,13 @@ uvc_function_set_alt(struct usb_function *f, unsigned interface, unsigned alt)
 	struct uvc_event *uvc_event = (void *)&v4l2_event.u.data;
 	int ret;
 
-	INFO(cdev, "uvc_function_set_alt(%u, %u)\n", interface, alt);
+	uvcg_info(f, "%s(%u, %u)\n", __func__, interface, alt);
 
 	if (interface == uvc->control_intf) {
 		if (alt)
 			return -EINVAL;
 
-		INFO(cdev, "reset UVC Control\n");
+		uvcg_info(f, "reset UVC Control\n");
 		usb_ep_disable(uvc->control_ep);
 
 		if (!uvc->control_ep->desc)
@@ -348,7 +337,7 @@ uvc_function_set_alt(struct usb_function *f, unsigned interface, unsigned alt)
 		if (!uvc->video.ep)
 			return -EINVAL;
 
-		INFO(cdev, "reset UVC\n");
+		uvcg_info(f, "reset UVC\n");
 		usb_ep_disable(uvc->video.ep);
 
 		ret = config_ep_by_speed(f->config->cdev->gadget,
@@ -373,7 +362,7 @@ uvc_function_disable(struct usb_function *f)
 	struct uvc_device *uvc = to_uvc(f);
 	struct v4l2_event v4l2_event;
 
-	INFO(f->config->cdev, "uvc_function_disable\n");
+	uvcg_info(f, "%s()\n", __func__);
 
 	memset(&v4l2_event, 0, sizeof(v4l2_event));
 	v4l2_event.type = UVC_EVENT_DISCONNECT;
@@ -392,21 +381,19 @@ uvc_function_disable(struct usb_function *f)
 void
 uvc_function_connect(struct uvc_device *uvc)
 {
-	struct usb_composite_dev *cdev = uvc->func.config->cdev;
 	int ret;
 
 	if ((ret = usb_function_activate(&uvc->func)) < 0)
-		INFO(cdev, "UVC connect failed with %d\n", ret);
+		uvcg_info(&uvc->func, "UVC connect failed with %d\n", ret);
 }
 
 void
 uvc_function_disconnect(struct uvc_device *uvc)
 {
-	struct usb_composite_dev *cdev = uvc->func.config->cdev;
 	int ret;
 
 	if ((ret = usb_function_deactivate(&uvc->func)) < 0)
-		INFO(cdev, "UVC disconnect failed with %d\n", ret);
+		uvcg_info(&uvc->func, "UVC disconnect failed with %d\n", ret);
 }
 
 /* --------------------------------------------------------------------------
@@ -605,7 +592,7 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 	struct f_uvc_opts *opts;
 	int ret = -EINVAL;
 
-	INFO(cdev, "uvc_function_bind\n");
+	uvcg_info(f, "%s()\n", __func__);
 
 	opts = fi_to_f_uvc_opts(f->fi);
 	/* Sanity check the streaming endpoint module parameters.
@@ -618,8 +605,8 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 	if (opts->streaming_maxburst &&
 	    (opts->streaming_maxpacket % 1024) != 0) {
 		opts->streaming_maxpacket = roundup(opts->streaming_maxpacket, 1024);
-		INFO(cdev, "overriding streaming_maxpacket to %d\n",
-		     opts->streaming_maxpacket);
+		uvcg_info(f, "overriding streaming_maxpacket to %d\n",
+			  opts->streaming_maxpacket);
 	}
 
 	/* Fill in the FS/HS/SS Video Streaming specific descriptors from the
@@ -658,7 +645,7 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 	/* Allocate endpoints. */
 	ep = usb_ep_autoconfig(cdev->gadget, &uvc_control_ep);
 	if (!ep) {
-		INFO(cdev, "Unable to allocate control EP\n");
+		uvcg_info(f, "Unable to allocate control EP\n");
 		goto error;
 	}
 	uvc->control_ep = ep;
@@ -672,7 +659,7 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 		ep = usb_ep_autoconfig(cdev->gadget, &uvc_fs_streaming_ep);
 
 	if (!ep) {
-		INFO(cdev, "Unable to allocate streaming EP\n");
+		uvcg_info(f, "Unable to allocate streaming EP\n");
 		goto error;
 	}
 	uvc->video.ep = ep;
@@ -699,12 +686,14 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 	uvc_iad.bFirstInterface = ret;
 	uvc_control_intf.bInterfaceNumber = ret;
 	uvc->control_intf = ret;
+	opts->control_interface = ret;
 
 	if ((ret = usb_interface_id(c, f)) < 0)
 		goto error;
 	uvc_streaming_intf_alt0.bInterfaceNumber = ret;
 	uvc_streaming_intf_alt1.bInterfaceNumber = ret;
 	uvc->streaming_intf = ret;
+	opts->streaming_interface = ret;
 
 	/* Copy descriptors */
 	f->fs_descriptors = uvc_copy_descriptors(uvc, USB_SPEED_FULL);
@@ -743,19 +732,19 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 	uvc->control_req->context = uvc;
 
 	if (v4l2_device_register(&cdev->gadget->dev, &uvc->v4l2_dev)) {
-		printk(KERN_INFO "v4l2_device_register failed\n");
+		uvcg_err(f, "failed to register V4L2 device\n");
 		goto error;
 	}
 
 	/* Initialise video. */
-	ret = uvcg_video_init(&uvc->video);
+	ret = uvcg_video_init(&uvc->video, uvc);
 	if (ret < 0)
 		goto error;
 
 	/* Register a V4L2 device. */
 	ret = uvc_register_video(uvc);
 	if (ret < 0) {
-		printk(KERN_INFO "Unable to register video device\n");
+		uvcg_err(f, "failed to register video device\n");
 		goto error;
 	}
 
@@ -792,6 +781,7 @@ static struct usb_function_instance *uvc_alloc_inst(void)
 	struct uvc_output_terminal_descriptor *od;
 	struct uvc_color_matching_descriptor *md;
 	struct uvc_descriptor_header **ctl_cls;
+	int ret;
 
 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 	if (!opts)
@@ -868,7 +858,12 @@ static struct usb_function_instance *uvc_alloc_inst(void)
 	opts->streaming_interval = 1;
 	opts->streaming_maxpacket = 1024;
 
-	uvcg_attach_configfs(opts);
+	ret = uvcg_attach_configfs(opts);
+	if (ret < 0) {
+		kfree(opts);
+		return ERR_PTR(ret);
+	}
+
 	return &opts->func_inst;
 }
 
@@ -886,7 +881,7 @@ static void uvc_unbind(struct usb_configuration *c, struct usb_function *f)
 	struct usb_composite_dev *cdev = c->cdev;
 	struct uvc_device *uvc = to_uvc(f);
 
-	INFO(cdev, "%s\n", __func__);
+	uvcg_info(f, "%s\n", __func__);
 
 	device_remove_file(&uvc->vdev.dev, &dev_attr_function_name);
 	video_unregister_device(&uvc->vdev);
diff --git a/drivers/usb/gadget/function/u_uvc.h b/drivers/usb/gadget/function/u_uvc.h
index 2ed292e94fbc..5242d489e20a 100644
--- a/drivers/usb/gadget/function/u_uvc.h
+++ b/drivers/usb/gadget/function/u_uvc.h
@@ -25,6 +25,9 @@ struct f_uvc_opts {
 	unsigned int					streaming_maxpacket;
 	unsigned int					streaming_maxburst;
 
+	unsigned int					control_interface;
+	unsigned int					streaming_interface;
+
 	/*
 	 * Control descriptors array pointers for full-/high-speed and
 	 * super-speed. They point by default to the uvc_fs_control_cls and
diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h
index 93cf78b420fe..099d650082e5 100644
--- a/drivers/usb/gadget/function/uvc.h
+++ b/drivers/usb/gadget/function/uvc.h
@@ -24,6 +24,7 @@
 struct usb_ep;
 struct usb_request;
 struct uvc_descriptor_header;
+struct uvc_device;
 
 /* ------------------------------------------------------------------------
  * Debugging, printing and logging
@@ -51,14 +52,12 @@ extern unsigned int uvc_gadget_trace_param;
 			printk(KERN_DEBUG "uvcvideo: " msg); \
 	} while (0)
 
-#define uvc_warn_once(dev, warn, msg...) \
-	do { \
-		if (!test_and_set_bit(warn, &dev->warnings)) \
-			printk(KERN_INFO "uvcvideo: " msg); \
-	} while (0)
-
-#define uvc_printk(level, msg...) \
-	printk(level "uvcvideo: " msg)
+#define uvcg_dbg(f, fmt, args...) \
+	dev_dbg(&(f)->config->cdev->gadget->dev, "%s: " fmt, (f)->name, ##args)
+#define uvcg_info(f, fmt, args...) \
+	dev_info(&(f)->config->cdev->gadget->dev, "%s: " fmt, (f)->name, ##args)
+#define uvcg_err(f, fmt, args...) \
+	dev_err(&(f)->config->cdev->gadget->dev, "%s: " fmt, (f)->name, ##args)
 
 /* ------------------------------------------------------------------------
  * Driver specific constants
@@ -73,6 +72,7 @@ extern unsigned int uvc_gadget_trace_param;
  */
 
 struct uvc_video {
+	struct uvc_device *uvc;
 	struct usb_ep *ep;
 
 	/* Frame parameters */
diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c
index b51f0d278826..bc1e2af566c3 100644
--- a/drivers/usb/gadget/function/uvc_configfs.c
+++ b/drivers/usb/gadget/function/uvc_configfs.c
@@ -9,9 +9,16 @@
  *
  * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
  */
+
+#include <linux/sort.h>
+
 #include "u_uvc.h"
 #include "uvc_configfs.h"
 
+/* -----------------------------------------------------------------------------
+ * Global Utility Structures and Macros
+ */
+
 #define UVCG_STREAMING_CONTROL_SIZE	1
 
 #define UVC_ATTR(prefix, cname, aname) \
@@ -31,13 +38,93 @@ static struct configfs_attribute prefix##attr_##cname = { \
 	.show		= prefix##cname##_show,				\
 }
 
+#define le8_to_cpu(x)	(x)
+#define cpu_to_le8(x)	(x)
+
+static int uvcg_config_compare_u32(const void *l, const void *r)
+{
+	u32 li = *(const u32 *)l;
+	u32 ri = *(const u32 *)r;
+
+	return li < ri ? -1 : li == ri ? 0 : 1;
+}
+
 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);
 }
 
-/* control/header/<NAME> */
+struct uvcg_config_group_type {
+	struct config_item_type type;
+	const char *name;
+	const struct uvcg_config_group_type **children;
+	int (*create_children)(struct config_group *group);
+};
+
+static void uvcg_config_item_release(struct config_item *item)
+{
+	struct config_group *group = to_config_group(item);
+
+	kfree(group);
+}
+
+static struct configfs_item_operations uvcg_config_item_ops = {
+	.release	= uvcg_config_item_release,
+};
+
+static int uvcg_config_create_group(struct config_group *parent,
+				    const struct uvcg_config_group_type *type);
+
+static int uvcg_config_create_children(struct config_group *group,
+				const struct uvcg_config_group_type *type)
+{
+	const struct uvcg_config_group_type **child;
+	int ret;
+
+	if (type->create_children)
+		return type->create_children(group);
+
+	for (child = type->children; child && *child; ++child) {
+		ret = uvcg_config_create_group(group, *child);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int uvcg_config_create_group(struct config_group *parent,
+				    const struct uvcg_config_group_type *type)
+{
+	struct config_group *group;
+
+	group = kzalloc(sizeof(*group), GFP_KERNEL);
+	if (!group)
+		return -ENOMEM;
+
+	config_group_init_type_name(group, type->name, &type->type);
+	configfs_add_default_group(group, parent);
+
+	return uvcg_config_create_children(group, type);
+}
+
+static void uvcg_config_remove_children(struct config_group *group)
+{
+	struct config_group *child, *n;
+
+	list_for_each_entry_safe(child, n, &group->default_groups, group_entry) {
+		list_del(&child->group_entry);
+		uvcg_config_remove_children(child);
+		config_item_put(&child->cg_item);
+	}
+}
+
+/* -----------------------------------------------------------------------------
+ * control/header/<NAME>
+ * control/header
+ */
+
 DECLARE_UVC_HEADER_DESCRIPTOR(1);
 
 struct uvcg_control_header {
@@ -51,9 +138,9 @@ static struct uvcg_control_header *to_uvcg_control_header(struct config_item *it
 	return container_of(item, struct uvcg_control_header, item);
 }
 
-#define UVCG_CTRL_HDR_ATTR(cname, aname, conv, str2u, uxx, vnoc, limit)	\
+#define UVCG_CTRL_HDR_ATTR(cname, aname, bits, limit)			\
 static ssize_t uvcg_control_header_##cname##_show(			\
-	struct config_item *item, char *page)			\
+	struct config_item *item, char *page)				\
 {									\
 	struct uvcg_control_header *ch = to_uvcg_control_header(item);	\
 	struct f_uvc_opts *opts;					\
@@ -67,7 +154,7 @@ static ssize_t uvcg_control_header_##cname##_show(			\
 	opts = to_f_uvc_opts(opts_item);				\
 									\
 	mutex_lock(&opts->lock);					\
-	result = sprintf(page, "%d\n", conv(ch->desc.aname));		\
+	result = sprintf(page, "%u\n", le##bits##_to_cpu(ch->desc.aname));\
 	mutex_unlock(&opts->lock);					\
 									\
 	mutex_unlock(su_mutex);						\
@@ -83,7 +170,7 @@ uvcg_control_header_##cname##_store(struct config_item *item,		\
 	struct config_item *opts_item;					\
 	struct mutex *su_mutex = &ch->item.ci_group->cg_subsys->su_mutex;\
 	int ret;							\
-	uxx num;							\
+	u##bits num;							\
 									\
 	mutex_lock(su_mutex); /* for navigating configfs hierarchy */	\
 									\
@@ -96,7 +183,7 @@ uvcg_control_header_##cname##_store(struct config_item *item,		\
 		goto end;						\
 	}								\
 									\
-	ret = str2u(page, 0, &num);					\
+	ret = kstrtou##bits(page, 0, &num);				\
 	if (ret)							\
 		goto end;						\
 									\
@@ -104,7 +191,7 @@ uvcg_control_header_##cname##_store(struct config_item *item,		\
 		ret = -EINVAL;						\
 		goto end;						\
 	}								\
-	ch->desc.aname = vnoc(num);					\
+	ch->desc.aname = cpu_to_le##bits(num);				\
 	ret = len;							\
 end:									\
 	mutex_unlock(&opts->lock);					\
@@ -114,11 +201,9 @@ end:									\
 									\
 UVC_ATTR(uvcg_control_header_, cname, aname)
 
-UVCG_CTRL_HDR_ATTR(bcd_uvc, bcdUVC, le16_to_cpu, kstrtou16, u16, cpu_to_le16,
-		   0xffff);
+UVCG_CTRL_HDR_ATTR(bcd_uvc, bcdUVC, 16, 0xffff);
 
-UVCG_CTRL_HDR_ATTR(dw_clock_frequency, dwClockFrequency, le32_to_cpu, kstrtou32,
-		   u32, cpu_to_le32, 0x7fffffff);
+UVCG_CTRL_HDR_ATTR(dw_clock_frequency, dwClockFrequency, 32, 0x7fffffff);
 
 #undef UVCG_CTRL_HDR_ATTR
 
@@ -129,6 +214,7 @@ static struct configfs_attribute *uvcg_control_header_attrs[] = {
 };
 
 static const struct config_item_type uvcg_control_header_type = {
+	.ct_item_ops	= &uvcg_config_item_ops,
 	.ct_attrs	= uvcg_control_header_attrs,
 	.ct_owner	= THIS_MODULE,
 };
@@ -153,60 +239,42 @@ static struct config_item *uvcg_control_header_make(struct config_group *group,
 	return &h->item;
 }
 
-static 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 const struct config_item_type uvcg_control_header_grp_type = {
-	.ct_group_ops	= &uvcg_control_header_grp_ops,
-	.ct_owner	= THIS_MODULE,
+static const struct uvcg_config_group_type uvcg_control_header_grp_type = {
+	.type = {
+		.ct_item_ops	= &uvcg_config_item_ops,
+		.ct_group_ops	= &uvcg_control_header_grp_ops,
+		.ct_owner	= THIS_MODULE,
+	},
+	.name = "header",
 };
 
-/* 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);
-}
+/* -----------------------------------------------------------------------------
+ * control/processing/default
+ */
 
-#define UVCG_DEFAULT_PROCESSING_ATTR(cname, aname, conv)		\
+#define UVCG_DEFAULT_PROCESSING_ATTR(cname, aname, bits)		\
 static ssize_t uvcg_default_processing_##cname##_show(			\
 	struct config_item *item, char *page)				\
 {									\
-	struct uvcg_default_processing *dp = to_uvcg_default_processing(item); \
+	struct config_group *group = to_config_group(item);		\
 	struct f_uvc_opts *opts;					\
 	struct config_item *opts_item;					\
-	struct mutex *su_mutex = &dp->group.cg_subsys->su_mutex;	\
+	struct mutex *su_mutex = &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_item = 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));		\
+	result = sprintf(page, "%u\n", le##bits##_to_cpu(pd->aname));	\
 	mutex_unlock(&opts->lock);					\
 									\
 	mutex_unlock(su_mutex);						\
@@ -215,37 +283,33 @@ static ssize_t uvcg_default_processing_##cname##_show(			\
 									\
 UVC_ATTR_RO(uvcg_default_processing_, cname, aname)
 
-#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
+UVCG_DEFAULT_PROCESSING_ATTR(b_unit_id, bUnitID, 8);
+UVCG_DEFAULT_PROCESSING_ATTR(b_source_id, bSourceID, 8);
+UVCG_DEFAULT_PROCESSING_ATTR(w_max_multiplier, wMaxMultiplier, 16);
+UVCG_DEFAULT_PROCESSING_ATTR(i_processing, iProcessing, 8);
 
 #undef UVCG_DEFAULT_PROCESSING_ATTR
 
 static ssize_t uvcg_default_processing_bm_controls_show(
 	struct config_item *item, char *page)
 {
-	struct uvcg_default_processing *dp = to_uvcg_default_processing(item);
+	struct config_group *group = to_config_group(item);
 	struct f_uvc_opts *opts;
 	struct config_item *opts_item;
-	struct mutex *su_mutex = &dp->group.cg_subsys->su_mutex;
+	struct mutex *su_mutex = &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_item = 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]);
+		result += sprintf(pg, "%u\n", pd->bmControls[i]);
 		pg = page + result;
 	}
 	mutex_unlock(&opts->lock);
@@ -266,54 +330,55 @@ static struct configfs_attribute *uvcg_default_processing_attrs[] = {
 	NULL,
 };
 
-static const struct config_item_type uvcg_default_processing_type = {
-	.ct_attrs	= uvcg_default_processing_attrs,
-	.ct_owner	= THIS_MODULE,
+static const struct uvcg_config_group_type uvcg_default_processing_type = {
+	.type = {
+		.ct_item_ops	= &uvcg_config_item_ops,
+		.ct_attrs	= uvcg_default_processing_attrs,
+		.ct_owner	= THIS_MODULE,
+	},
+	.name = "default",
 };
 
-/* struct uvcg_processing {}; */
-
-/* control/processing */
-static struct uvcg_processing_grp {
-	struct config_group	group;
-} uvcg_processing_grp;
+/* -----------------------------------------------------------------------------
+ * control/processing
+ */
 
-static const struct config_item_type uvcg_processing_grp_type = {
-	.ct_owner = THIS_MODULE,
+static const struct uvcg_config_group_type uvcg_processing_grp_type = {
+	.type = {
+		.ct_item_ops	= &uvcg_config_item_ops,
+		.ct_owner	= THIS_MODULE,
+	},
+	.name = "processing",
+	.children = (const struct uvcg_config_group_type*[]) {
+		&uvcg_default_processing_type,
+		NULL,
+	},
 };
 
-/* 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);
-}
+/* -----------------------------------------------------------------------------
+ * control/terminal/camera/default
+ */
 
-#define UVCG_DEFAULT_CAMERA_ATTR(cname, aname, conv)			\
+#define UVCG_DEFAULT_CAMERA_ATTR(cname, aname, bits)			\
 static ssize_t uvcg_default_camera_##cname##_show(			\
 	struct config_item *item, char *page)				\
 {									\
-	struct uvcg_default_camera *dc = to_uvcg_default_camera(item);	\
+	struct config_group *group = to_config_group(item);		\
 	struct f_uvc_opts *opts;					\
 	struct config_item *opts_item;					\
-	struct mutex *su_mutex = &dc->group.cg_subsys->su_mutex;	\
+	struct mutex *su_mutex = &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->	\
+	opts_item = 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));		\
+	result = sprintf(page, "%u\n", le##bits##_to_cpu(cd->aname));	\
 	mutex_unlock(&opts->lock);					\
 									\
 	mutex_unlock(su_mutex);						\
@@ -323,44 +388,40 @@ static ssize_t uvcg_default_camera_##cname##_show(			\
 									\
 UVC_ATTR_RO(uvcg_default_camera_, cname, aname)
 
-#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(b_terminal_id, bTerminalID, 8);
+UVCG_DEFAULT_CAMERA_ATTR(w_terminal_type, wTerminalType, 16);
+UVCG_DEFAULT_CAMERA_ATTR(b_assoc_terminal, bAssocTerminal, 8);
+UVCG_DEFAULT_CAMERA_ATTR(i_terminal, iTerminal, 8);
 UVCG_DEFAULT_CAMERA_ATTR(w_objective_focal_length_min, wObjectiveFocalLengthMin,
-			 le16_to_cpu);
+			 16);
 UVCG_DEFAULT_CAMERA_ATTR(w_objective_focal_length_max, wObjectiveFocalLengthMax,
-			 le16_to_cpu);
+			 16);
 UVCG_DEFAULT_CAMERA_ATTR(w_ocular_focal_length, wOcularFocalLength,
-			 le16_to_cpu);
-
-#undef identity_conv
+			 16);
 
 #undef UVCG_DEFAULT_CAMERA_ATTR
 
 static ssize_t uvcg_default_camera_bm_controls_show(
 	struct config_item *item, char *page)
 {
-	struct uvcg_default_camera *dc = to_uvcg_default_camera(item);
+	struct config_group *group = to_config_group(item);
 	struct f_uvc_opts *opts;
 	struct config_item *opts_item;
-	struct mutex *su_mutex = &dc->group.cg_subsys->su_mutex;
+	struct mutex *su_mutex = &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->
+	opts_item = 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]);
+		result += sprintf(pg, "%u\n", cd->bmControls[i]);
 		pg = page + result;
 	}
 	mutex_unlock(&opts->lock);
@@ -383,54 +444,55 @@ static struct configfs_attribute *uvcg_default_camera_attrs[] = {
 	NULL,
 };
 
-static const struct config_item_type uvcg_default_camera_type = {
-	.ct_attrs	= uvcg_default_camera_attrs,
-	.ct_owner	= THIS_MODULE,
+static const struct uvcg_config_group_type uvcg_default_camera_type = {
+	.type = {
+		.ct_item_ops	= &uvcg_config_item_ops,
+		.ct_attrs	= uvcg_default_camera_attrs,
+		.ct_owner	= THIS_MODULE,
+	},
+	.name = "default",
 };
 
-/* struct uvcg_camera {}; */
-
-/* control/terminal/camera */
-static struct uvcg_camera_grp {
-	struct config_group	group;
-} uvcg_camera_grp;
+/* -----------------------------------------------------------------------------
+ * control/terminal/camera
+ */
 
-static const struct config_item_type uvcg_camera_grp_type = {
-	.ct_owner = THIS_MODULE,
+static const struct uvcg_config_group_type uvcg_camera_grp_type = {
+	.type = {
+		.ct_item_ops	= &uvcg_config_item_ops,
+		.ct_owner	= THIS_MODULE,
+	},
+	.name = "camera",
+	.children = (const struct uvcg_config_group_type*[]) {
+		&uvcg_default_camera_type,
+		NULL,
+	},
 };
 
-/* 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);
-}
+/* -----------------------------------------------------------------------------
+ * control/terminal/output/default
+ */
 
-#define UVCG_DEFAULT_OUTPUT_ATTR(cname, aname, conv)			\
+#define UVCG_DEFAULT_OUTPUT_ATTR(cname, aname, bits)			\
 static ssize_t uvcg_default_output_##cname##_show(			\
-	struct config_item *item, char *page)			\
+	struct config_item *item, char *page)				\
 {									\
-	struct uvcg_default_output *dout = to_uvcg_default_output(item); \
+	struct config_group *group = to_config_group(item);		\
 	struct f_uvc_opts *opts;					\
 	struct config_item *opts_item;					\
-	struct mutex *su_mutex = &dout->group.cg_subsys->su_mutex;	\
+	struct mutex *su_mutex = &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->		\
+	opts_item = 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));		\
+	result = sprintf(page, "%u\n", le##bits##_to_cpu(cd->aname));	\
 	mutex_unlock(&opts->lock);					\
 									\
 	mutex_unlock(su_mutex);						\
@@ -440,15 +502,11 @@ static ssize_t uvcg_default_output_##cname##_show(			\
 									\
 UVC_ATTR_RO(uvcg_default_output_, cname, aname)
 
-#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
+UVCG_DEFAULT_OUTPUT_ATTR(b_terminal_id, bTerminalID, 8);
+UVCG_DEFAULT_OUTPUT_ATTR(w_terminal_type, wTerminalType, 16);
+UVCG_DEFAULT_OUTPUT_ATTR(b_assoc_terminal, bAssocTerminal, 8);
+UVCG_DEFAULT_OUTPUT_ATTR(b_source_id, bSourceID, 8);
+UVCG_DEFAULT_OUTPUT_ATTR(i_terminal, iTerminal, 8);
 
 #undef UVCG_DEFAULT_OUTPUT_ATTR
 
@@ -461,47 +519,68 @@ static struct configfs_attribute *uvcg_default_output_attrs[] = {
 	NULL,
 };
 
-static const struct config_item_type uvcg_default_output_type = {
-	.ct_attrs	= uvcg_default_output_attrs,
-	.ct_owner	= THIS_MODULE,
+static const struct uvcg_config_group_type uvcg_default_output_type = {
+	.type = {
+		.ct_item_ops	= &uvcg_config_item_ops,
+		.ct_attrs	= uvcg_default_output_attrs,
+		.ct_owner	= THIS_MODULE,
+	},
+	.name = "default",
 };
 
-/* struct uvcg_output {}; */
-
-/* control/terminal/output */
-static struct uvcg_output_grp {
-	struct config_group	group;
-} uvcg_output_grp;
+/* -----------------------------------------------------------------------------
+ * control/terminal/output
+ */
 
-static const struct config_item_type uvcg_output_grp_type = {
-	.ct_owner = THIS_MODULE,
+static const struct uvcg_config_group_type uvcg_output_grp_type = {
+	.type = {
+		.ct_item_ops	= &uvcg_config_item_ops,
+		.ct_owner	= THIS_MODULE,
+	},
+	.name = "output",
+	.children = (const struct uvcg_config_group_type*[]) {
+		&uvcg_default_output_type,
+		NULL,
+	},
 };
 
-/* control/terminal */
-static struct uvcg_terminal_grp {
-	struct config_group	group;
-} uvcg_terminal_grp;
+/* -----------------------------------------------------------------------------
+ * control/terminal
+ */
 
-static const struct config_item_type uvcg_terminal_grp_type = {