drm/vc4: Attach margin props to the HDMI connector

Now that the plane code takes the margins setup into account, we can
safely attach margin props to the HDMI connector.

We also take care of filling AVI infoframes correctly to expose the
top/botton/left/right bar.

Note that those margin props match pretty well the
overscan_{left,right,top,bottom} properties defined in config.txt and
parsed by the VC4 firmware.
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20181206142439.10441-6-boris.brezillon@bootlin.com

drivers/gpu/drm/vc4/vc4_hdmi.c

@@ -310,6 +310,7 @@ static struct drm_connector *vc4_hdmi_connector_init(struct drm_device *dev,
 {
 	struct drm_connector *connector;
 	struct vc4_hdmi_connector *hdmi_connector;
+	int ret;
 
 	hdmi_connector = devm_kzalloc(dev->dev, sizeof(*hdmi_connector),
 				      GFP_KERNEL);
@@ -323,6 +324,13 @@ static struct drm_connector *vc4_hdmi_connector_init(struct drm_device *dev,
 			   DRM_MODE_CONNECTOR_HDMIA);
 	drm_connector_helper_add(connector, &vc4_hdmi_connector_helper_funcs);
 
+	/* Create and attach TV margin props to this connector. */
+	ret = drm_mode_create_tv_margin_properties(dev);
+	if (ret)
+		return ERR_PTR(ret);
+
+	drm_connector_attach_tv_margin_properties(connector);
+
 	connector->polled = (DRM_CONNECTOR_POLL_CONNECT |
 			     DRM_CONNECTOR_POLL_DISCONNECT);
 
@@ -408,6 +416,9 @@ static void vc4_hdmi_write_infoframe(struct drm_encoder *encoder,
 static void vc4_hdmi_set_avi_infoframe(struct drm_encoder *encoder)
 {
 	struct vc4_hdmi_encoder *vc4_encoder = to_vc4_hdmi_encoder(encoder);
+	struct vc4_dev *vc4 = encoder->dev->dev_private;
+	struct vc4_hdmi *hdmi = vc4->hdmi;
+	struct drm_connector_state *cstate = hdmi->connector->state;
 	struct drm_crtc *crtc = encoder->crtc;
 	const struct drm_display_mode *mode = &crtc->state->adjusted_mode;
 	union hdmi_infoframe frame;
@@ -426,6 +437,11 @@ static void vc4_hdmi_set_avi_infoframe(struct drm_encoder *encoder)
 					   vc4_encoder->rgb_range_selectable,
 					   false);
 
+	frame.avi.right_bar = cstate->tv.margins.right;
+	frame.avi.left_bar = cstate->tv.margins.left;
+	frame.avi.top_bar = cstate->tv.margins.top;
+	frame.avi.bottom_bar = cstate->tv.margins.bottom;
+
 	vc4_hdmi_write_infoframe(encoder, &frame);
 }