V4L/DVB (12534): soc-camera: V4L2 API compliant scaling (S_FMT) and cropping (S_CROP)

The initial soc-camera scaling and cropping implementation turned out to be
incompliant with the V4L2 API, e.g., it expected the user to specify cropping
in output window pixels, instead of input window pixels. This patch converts
the soc-camera core and all drivers to comply with the standard.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

include/media/soc_camera.h

@@ -22,8 +22,8 @@ struct soc_camera_device {
 	struct list_head list;
 	struct device dev;
 	struct device *pdev;		/* Platform device */
-	struct v4l2_rect rect_current;	/* Current window */
-	struct v4l2_rect rect_max;	/* Maximum window */
+	s32 user_width;
+	s32 user_height;
 	unsigned short width_min;
 	unsigned short height_min;
 	unsigned short y_skip_top;	/* Lines to skip at the top */
@@ -76,6 +76,8 @@ struct soc_camera_host_ops {
 	int (*get_formats)(struct soc_camera_device *, int,
 			   struct soc_camera_format_xlate *);
 	void (*put_formats)(struct soc_camera_device *);
+	int (*cropcap)(struct soc_camera_device *, struct v4l2_cropcap *);
+	int (*get_crop)(struct soc_camera_device *, struct v4l2_crop *);
 	int (*set_crop)(struct soc_camera_device *, struct v4l2_crop *);
 	int (*set_fmt)(struct soc_camera_device *, struct v4l2_format *);
 	int (*try_fmt)(struct soc_camera_device *, struct v4l2_format *);
@@ -277,6 +279,21 @@ static inline unsigned long soc_camera_bus_param_compatible(
 		common_flags;
 }
 
+static inline void soc_camera_limit_side(unsigned int *start,
+		unsigned int *length, unsigned int start_min,
+		unsigned int length_min, unsigned int length_max)
+{
+	if (*length < length_min)
+		*length = length_min;
+	else if (*length > length_max)
+		*length = length_max;
+
+	if (*start < start_min)
+		*start = start_min;
+	else if (*start > start_min + length_max - *length)
+		*start = start_min + length_max - *length;
+}
+
 extern unsigned long soc_camera_apply_sensor_flags(struct soc_camera_link *icl,
 						   unsigned long flags);