media: v4l2-ctrl: Move compound control initialization

Rework std_init adding an explicit initialization for
compound controls.

While here, make sure the control is initialized to zero,
before providing default values for all its fields.
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
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

@@ -1494,10 +1494,13 @@ static bool std_equal(const struct v4l2_ctrl *ctrl, u32 idx,
 	}
 }
 
-static void std_init(const struct v4l2_ctrl *ctrl, u32 idx,
-		     union v4l2_ctrl_ptr ptr)
+static void std_init_compound(const struct v4l2_ctrl *ctrl, u32 idx,
+			      union v4l2_ctrl_ptr ptr)
 {
 	struct v4l2_ctrl_mpeg2_slice_params *p_mpeg2_slice_params;
+	void *p = ptr.p + idx * ctrl->elem_size;
+
+	memset(p, 0, ctrl->elem_size);
 
 	/*
 	 * The cast is needed to get rid of a gcc warning complaining that
@@ -1505,6 +1508,22 @@ static void std_init(const struct v4l2_ctrl *ctrl, u32 idx,
 	 * v4l2_ctrl_type enum.
 	 */
 	switch ((u32)ctrl->type) {
+	case V4L2_CTRL_TYPE_MPEG2_SLICE_PARAMS:
+		p_mpeg2_slice_params = p;
+		/* 4:2:0 */
+		p_mpeg2_slice_params->sequence.chroma_format = 1;
+		/* interlaced top field */
+		p_mpeg2_slice_params->picture.picture_structure = 1;
+		p_mpeg2_slice_params->picture.picture_coding_type =
+					V4L2_MPEG2_PICTURE_CODING_TYPE_I;
+		break;
+	}
+}
+
+static void std_init(const struct v4l2_ctrl *ctrl, u32 idx,
+		     union v4l2_ctrl_ptr ptr)
+{
+	switch (ctrl->type) {
 	case V4L2_CTRL_TYPE_STRING:
 		idx *= ctrl->elem_size;
 		memset(ptr.p_char + idx, ' ', ctrl->minimum);
@@ -1533,20 +1552,8 @@ static void std_init(const struct v4l2_ctrl *ctrl, u32 idx,
 	case V4L2_CTRL_TYPE_U32:
 		ptr.p_u32[idx] = ctrl->default_value;
 		break;
-	case V4L2_CTRL_TYPE_MPEG2_SLICE_PARAMS:
-		p_mpeg2_slice_params = ptr.p;
-		/* 4:2:0 */
-		p_mpeg2_slice_params->sequence.chroma_format = 1;
-		/* 8 bits */
-		p_mpeg2_slice_params->picture.intra_dc_precision = 0;
-		/* interlaced top field */
-		p_mpeg2_slice_params->picture.picture_structure = 1;
-		p_mpeg2_slice_params->picture.picture_coding_type =
-					V4L2_MPEG2_PICTURE_CODING_TYPE_I;
-		break;
 	default:
-		idx *= ctrl->elem_size;
-		memset(ptr.p + idx, 0, ctrl->elem_size);
+		std_init_compound(ctrl, idx, ptr);
 		break;
 	}
 }