usb: gadget: uvc: Minimize #include in headers

In order to speed up compilation, only include the headers that are
strictly required within other headers. To that end, use forward
structure declaration and move #include statements to .c file as
appropriate.

While at it, sort headers alphabetically, and remove unneeded __KERNEL__
guards.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/gadget/function/f_uvc.c

@@ -6,16 +6,17 @@
  *	    Laurent Pinchart (laurent.pinchart@ideasonboard.com)
  */
 
-#include <linux/kernel.h>
-#include <linux/module.h>
 #include <linux/device.h>
 #include <linux/errno.h>
 #include <linux/fs.h>
+#include <linux/kernel.h>
 #include <linux/list.h>
+#include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/string.h>
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
+#include <linux/usb/g_uvc.h>
 #include <linux/usb/video.h>
 #include <linux/vmalloc.h>
 #include <linux/wait.h>

drivers/usb/gadget/function/f_uvc.h

@@ -9,10 +9,7 @@
 #ifndef _F_UVC_H_
 #define _F_UVC_H_
 
-#include <linux/usb/composite.h>
-#include <linux/usb/video.h>
-
-#include "uvc.h"
+struct uvc_device;
 
 void uvc_function_setup_continue(struct uvc_device *uvc);
 
@@ -21,4 +18,3 @@ void uvc_function_connect(struct uvc_device *uvc);
 void uvc_function_disconnect(struct uvc_device *uvc);
 
 #endif /* _F_UVC_H_ */
-

drivers/usb/gadget/function/u_uvc.h

@@ -13,6 +13,7 @@
 #ifndef U_UVC_H
 #define U_UVC_H
 
+#include <linux/mutex.h>
 #include <linux/usb/composite.h>
 #include <linux/usb/video.h>
 

drivers/usb/gadget/function/uvc.h

@@ -9,16 +9,22 @@
 #ifndef _UVC_GADGET_H_
 #define _UVC_GADGET_H_
 
-#include <linux/usb.h>	/* For usb_endpoint_* */
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
 #include <linux/usb/composite.h>
-#include <linux/usb/gadget.h>
-#include <linux/usb/g_uvc.h>
 #include <linux/videodev2.h>
-#include <media/v4l2-fh.h>
+
 #include <media/v4l2-device.h>
+#include <media/v4l2-dev.h>
+#include <media/v4l2-fh.h>
 
 #include "uvc_queue.h"
 
+struct usb_ep;
+struct usb_request;
+struct uvc_descriptor_header;
+
 /* ------------------------------------------------------------------------
  * Debugging, printing and logging
  */

drivers/usb/gadget/function/uvc_queue.h

@@ -2,13 +2,15 @@
 #ifndef _UVC_QUEUE_H_
 #define _UVC_QUEUE_H_
 
-#ifdef __KERNEL__
-
-#include <linux/kernel.h>
+#include <linux/list.h>
 #include <linux/poll.h>
-#include <linux/videodev2.h>
+#include <linux/spinlock.h>
+
 #include <media/videobuf2-v4l2.h>
 
+struct file;
+struct mutex;
+
 /* Maximum frame size in bytes, for sanity checking. */
 #define UVC_MAX_FRAME_SIZE	(16*1024*1024)
 /* Maximum number of video buffers. */
@@ -91,7 +93,5 @@ struct uvc_buffer *uvcg_queue_next_buffer(struct uvc_video_queue *queue,
 
 struct uvc_buffer *uvcg_queue_head(struct uvc_video_queue *queue);
 
-#endif /* __KERNEL__ */
-
 #endif /* _UVC_QUEUE_H_ */
 

drivers/usb/gadget/function/uvc_v4l2.c

@@ -6,10 +6,11 @@
  *	    Laurent Pinchart (laurent.pinchart@ideasonboard.com)
  */
 
-#include <linux/kernel.h>
 #include <linux/device.h>
 #include <linux/errno.h>
+#include <linux/kernel.h>
 #include <linux/list.h>
+#include <linux/usb/g_uvc.h>
 #include <linux/videodev2.h>
 #include <linux/vmalloc.h>
 #include <linux/wait.h>

drivers/usb/gadget/function/uvc_video.h

@@ -12,6 +12,8 @@
 #ifndef __UVC_VIDEO_H__
 #define __UVC_VIDEO_H__
 
+struct uvc_video;
+
 int uvcg_video_pump(struct uvc_video *video);
 
 int uvcg_video_enable(struct uvc_video *video, int enable);