staging: use videobuf2 framework for drivers/staging/dt3155v4l driver

This patch transforms drivers/staging/dt3155v4l driver to use videobuf2 framework.
Tested and works with "xawtv -f".

Either streaming API or read method should be selected during kernel configuration.

If both are selected into the driver (not possible without another patching),
either due to my misunderstanding or problems in xawtv (or both), I get kernel panic
after some start/stop of xawtv (not strictly reproducible).
Signed-off-by: Marin Mitov <mitov@issp.bas.bg>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/dt3155v4l/Kconfig

 config VIDEO_DT3155
 	tristate "DT3155 frame grabber, Video4Linux interface"
 	depends on PCI && VIDEO_DEV && VIDEO_V4L2
-	select VIDEOBUF_DMA_CONTIG
+	select VIDEOBUF2_DMA_CONTIG
 	default n
 	---help---
 	  Enables dt3155 device driver for the DataTranslation DT3155 frame grabber.
@@ -18,3 +18,11 @@ config DT3155_CCIR
 	---help---
 	  Select it for CCIR/50Hz (European region),
 	  or leave it unselected for RS-170/60Hz (North America).
+
+config DT3155_STREAMING
+	bool "Selects streaming capture method"
+	depends on VIDEO_DT3155
+	default y
+	---help---
+	  Select it if you want to use streaming of memory mapped buffers
+	  or leave it unselected if you want to use read method (one copy more).

drivers/staging/dt3155v4l/dt3155v4l.h

@@ -179,18 +179,13 @@ struct dt3155_stats {
  * struct dt3155_priv - private data structure
  *
  * @vdev:		pointer to video_device structure
- * @acq_fp		pointer to filp that starts acquisition
- * @streaming		streaming is negotiated
  * @pdev:		pointer to pci_dev structure
- * @vidq		pointer to videobuf_queue structure
+ * @q			pointer to vb2_queue structure
  * @curr_buf:		pointer to curren buffer
- * @thread		pointer to worker thraed
+ * @mux:		mutex to protect the instance
  * @irq_handler:	irq handler for the driver
- * @qt_ops		local copy of dma-contig qtype_ops
  * @dmaq		queue for dma buffers
- * @do_dma		wait queue of the kernel thread
- * @mux:		mutex to protect the instance
- * @lock		spinlock for videobuf queues
+ * @lock		spinlock for dma queue
  * @field_count		fields counter
  * @stats:		statistics structure
  * @users		open count
@@ -200,17 +195,12 @@ struct dt3155_stats {
  */
 struct dt3155_priv {
 	struct video_device *vdev;
-	struct file *acq_fp;
-	int streaming;
 	struct pci_dev *pdev;
-	struct videobuf_queue *vidq;
-	struct videobuf_buffer *curr_buf;
-	struct task_struct *thread;
+	struct vb2_queue *q;
+	struct vb2_buffer *curr_buf;
+	struct mutex mux;
 	irq_handler_t irq_handler;
-	struct videobuf_qtype_ops qt_ops;
 	struct list_head dmaq;
-	wait_queue_head_t do_dma;
-	struct mutex mux;
 	spinlock_t lock;
 	unsigned int field_count;
 	struct dt3155_stats stats;