media: add V4L2_CTRL_TYPE_AREA control type

This type contains the width and the height of a rectangular area.
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Ricardo Ribalda Delgado <ribalda@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/v4l2-core/v4l2-ctrls.c

@@ -1677,6 +1677,7 @@ static int std_validate_compound(const struct v4l2_ctrl *ctrl, u32 idx,
 {
 	struct v4l2_ctrl_mpeg2_slice_params *p_mpeg2_slice_params;
 	struct v4l2_ctrl_vp8_frame_header *p_vp8_frame_header;
+	struct v4l2_area *area;
 	void *p = ptr.p + idx * ctrl->elem_size;
 
 	switch ((u32)ctrl->type) {
@@ -1753,6 +1754,11 @@ static int std_validate_compound(const struct v4l2_ctrl *ctrl, u32 idx,
 		zero_padding(p_vp8_frame_header->entropy_header);
 		zero_padding(p_vp8_frame_header->coder_state);
 		break;
+	case V4L2_CTRL_TYPE_AREA:
+		area = p;
+		if (!area->width || !area->height)
+			return -EINVAL;
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -2427,6 +2433,9 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
 	case V4L2_CTRL_TYPE_VP8_FRAME_HEADER:
 		elem_size = sizeof(struct v4l2_ctrl_vp8_frame_header);
 		break;
+	case V4L2_CTRL_TYPE_AREA:
+		elem_size = sizeof(struct v4l2_area);
+		break;
 	default:
 		if (type < V4L2_CTRL_COMPOUND_TYPES)
 			elem_size = sizeof(s32);
@@ -4116,6 +4125,18 @@ int __v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s)
 }
 EXPORT_SYMBOL(__v4l2_ctrl_s_ctrl_string);
 
+int __v4l2_ctrl_s_ctrl_area(struct v4l2_ctrl *ctrl,
+			    const struct v4l2_area *area)
+{
+	lockdep_assert_held(ctrl->handler->lock);
+
+	/* It's a driver bug if this happens. */
+	WARN_ON(ctrl->type != V4L2_CTRL_TYPE_AREA);
+	*ctrl->p_new.p_area = *area;
+	return set_ctrl(NULL, ctrl, 0);
+}
+EXPORT_SYMBOL(__v4l2_ctrl_s_ctrl_area);
+
 void v4l2_ctrl_request_complete(struct media_request *req,
 				struct v4l2_ctrl_handler *main_hdl)
 {

include/media/v4l2-ctrls.h

@@ -50,6 +50,7 @@ struct poll_table_struct;
  * @p_h264_slice_params:	Pointer to a struct v4l2_ctrl_h264_slice_params.
  * @p_h264_decode_params:	Pointer to a struct v4l2_ctrl_h264_decode_params.
  * @p_vp8_frame_header:		Pointer to a VP8 frame header structure.
+ * @p_area:			Pointer to an area.
  * @p:				Pointer to a compound value.
  */
 union v4l2_ctrl_ptr {
@@ -68,6 +69,7 @@ union v4l2_ctrl_ptr {
 	struct v4l2_ctrl_h264_slice_params *p_h264_slice_params;
 	struct v4l2_ctrl_h264_decode_params *p_h264_decode_params;
 	struct v4l2_ctrl_vp8_frame_header *p_vp8_frame_header;
+	struct v4l2_area *p_area;
 	void *p;
 };
 
@@ -1087,6 +1089,46 @@ static inline int v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s)
 	return rval;
 }
 
+/**
+ * __v4l2_ctrl_s_ctrl_area() - Unlocked variant of v4l2_ctrl_s_ctrl_area().
+ *
+ * @ctrl:	The control.
+ * @area:	The new area.
+ *
+ * This sets the control's new area safely by going through the control
+ * framework. This function assumes the control's handler is already locked,
+ * allowing it to be used from within the &v4l2_ctrl_ops functions.
+ *
+ * This function is for area type controls only.
+ */
+int __v4l2_ctrl_s_ctrl_area(struct v4l2_ctrl *ctrl,
+			    const struct v4l2_area *area);
+
+/**
+ * v4l2_ctrl_s_ctrl_area() - Helper function to set a control's area value
+ *	 from within a driver.
+ *
+ * @ctrl:	The control.
+ * @area:	The new area.
+ *
+ * This sets the control's new area safely by going through the control
+ * framework. This function will lock the control's handler, so it cannot be
+ * used from within the &v4l2_ctrl_ops functions.
+ *
+ * This function is for area type controls only.
+ */
+static inline int v4l2_ctrl_s_ctrl_area(struct v4l2_ctrl *ctrl,
+					const struct v4l2_area *area)
+{
+	int rval;
+
+	v4l2_ctrl_lock(ctrl);
+	rval = __v4l2_ctrl_s_ctrl_area(ctrl, area);
+	v4l2_ctrl_unlock(ctrl);
+
+	return rval;
+}
+
 /* Internal helper functions that deal with control events. */
 extern const struct v4l2_subscribed_event_ops v4l2_ctrl_sub_ev_ops;
 

include/uapi/linux/videodev2.h

@@ -422,6 +422,11 @@ struct v4l2_fract {
 	__u32   denominator;
 };
 
+struct v4l2_area {
+	__u32   width;
+	__u32   height;
+};
+
 /**
   * struct v4l2_capability - Describes V4L2 device caps returned by VIDIOC_QUERYCAP
   *
@@ -1720,6 +1725,7 @@ enum v4l2_ctrl_type {
 	V4L2_CTRL_TYPE_U8	     = 0x0100,
 	V4L2_CTRL_TYPE_U16	     = 0x0101,
 	V4L2_CTRL_TYPE_U32	     = 0x0102,
+	V4L2_CTRL_TYPE_AREA          = 0x0106,
 };
 
 /*  Used in the VIDIOC_QUERYCTRL ioctl for querying controls */