drm: rcar-du: lvds: Convert to DRM panel bridge helper

Replace the manual panel handling with usage of the DRM panel bridge
helper. This simplifies the driver, and brings support for
DRM_BRIDGE_ATTACH_NO_CONNECTOR as an added bonus.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Tested-by: Kieran Bingham <kieran.bingham@ideasonboard.com> # On V3U
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>

drivers/gpu/drm/rcar-du/rcar_lvds.c

@@ -63,7 +63,6 @@ struct rcar_lvds {
 	struct drm_bridge bridge;
 
 	struct drm_bridge *next_bridge;
-	struct drm_connector connector;
 	struct drm_panel *panel;
 
 	void __iomem *mmio;
@@ -80,73 +79,11 @@ struct rcar_lvds {
 #define bridge_to_rcar_lvds(b) \
 	container_of(b, struct rcar_lvds, bridge)
 
-#define connector_to_rcar_lvds(c) \
-	container_of(c, struct rcar_lvds, connector)
-
 static void rcar_lvds_write(struct rcar_lvds *lvds, u32 reg, u32 data)
 {
 	iowrite32(data, lvds->mmio + reg);
 }
 
-/* -----------------------------------------------------------------------------
- * Connector & Panel
- */
-
-static int rcar_lvds_connector_get_modes(struct drm_connector *connector)
-{
-	struct rcar_lvds *lvds = connector_to_rcar_lvds(connector);
-
-	return drm_panel_get_modes(lvds->panel, connector);
-}
-
-static int rcar_lvds_connector_atomic_check(struct drm_connector *connector,
-					    struct drm_atomic_state *state)
-{
-	struct rcar_lvds *lvds = connector_to_rcar_lvds(connector);
-	const struct drm_display_mode *panel_mode;
-	struct drm_connector_state *conn_state;
-	struct drm_crtc_state *crtc_state;
-
-	conn_state = drm_atomic_get_new_connector_state(state, connector);
-	if (!conn_state->crtc)
-		return 0;
-
-	if (list_empty(&connector->modes)) {
-		dev_dbg(lvds->dev, "connector: empty modes list\n");
-		return -EINVAL;
-	}
-
-	panel_mode = list_first_entry(&connector->modes,
-				      struct drm_display_mode, head);
-
-	/* We're not allowed to modify the resolution. */
-	crtc_state = drm_atomic_get_crtc_state(state, conn_state->crtc);
-	if (IS_ERR(crtc_state))
-		return PTR_ERR(crtc_state);
-
-	if (crtc_state->mode.hdisplay != panel_mode->hdisplay ||
-	    crtc_state->mode.vdisplay != panel_mode->vdisplay)
-		return -EINVAL;
-
-	/* The flat panel mode is fixed, just copy it to the adjusted mode. */
-	drm_mode_copy(&crtc_state->adjusted_mode, panel_mode);
-
-	return 0;
-}
-
-static const struct drm_connector_helper_funcs rcar_lvds_conn_helper_funcs = {
-	.get_modes = rcar_lvds_connector_get_modes,
-	.atomic_check = rcar_lvds_connector_atomic_check,
-};
-
-static const struct drm_connector_funcs rcar_lvds_conn_funcs = {
-	.reset = drm_atomic_helper_connector_reset,
-	.fill_modes = drm_helper_probe_single_connector_modes,
-	.destroy = drm_connector_cleanup,
-	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
-	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
-};
-
 /* -----------------------------------------------------------------------------
  * PLL Setup
  */
@@ -583,11 +520,6 @@ static void __rcar_lvds_atomic_enable(struct drm_bridge *bridge,
 	/* Turn the output on. */
 	lvdcr0 |= LVDCR0_LVRES;
 	rcar_lvds_write(lvds, LVDCR0, lvdcr0);
-
-	if (lvds->panel) {
-		drm_panel_prepare(lvds->panel);
-		drm_panel_enable(lvds->panel);
-	}
 }
 
 static void rcar_lvds_atomic_enable(struct drm_bridge *bridge,
@@ -609,11 +541,6 @@ static void rcar_lvds_atomic_disable(struct drm_bridge *bridge,
 {
 	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
 
-	if (lvds->panel) {
-		drm_panel_disable(lvds->panel);
-		drm_panel_unprepare(lvds->panel);
-	}
-
 	rcar_lvds_write(lvds, LVDCR0, 0);
 	rcar_lvds_write(lvds, LVDCR1, 0);
 	rcar_lvds_write(lvds, LVDPLLCR, 0);
@@ -648,45 +575,13 @@ static int rcar_lvds_attach(struct drm_bridge *bridge,
 			    enum drm_bridge_attach_flags flags)
 {
 	struct rcar_lvds *lvds = bridge_to_rcar_lvds(bridge);
-	struct drm_connector *connector = &lvds->connector;
-	struct drm_encoder *encoder = bridge->encoder;
-	int ret;
-
-	/* If we have a next bridge just attach it. */
-	if (lvds->next_bridge)
-		return drm_bridge_attach(bridge->encoder, lvds->next_bridge,
-					 bridge, flags);
-
-	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
-		DRM_ERROR("Fix bridge driver to make connector optional!");
-		return -EINVAL;
-	}
-
-	/* Otherwise if we have a panel, create a connector. */
-	if (!lvds->panel)
-		return 0;
-
-	ret = drm_connector_init(bridge->dev, connector, &rcar_lvds_conn_funcs,
-				 DRM_MODE_CONNECTOR_LVDS);
-	if (ret < 0)
-		return ret;
-
-	drm_connector_helper_add(connector, &rcar_lvds_conn_helper_funcs);
-
-	ret = drm_connector_attach_encoder(connector, encoder);
-	if (ret < 0)
-		return ret;
-
-	return 0;
-}
 
-static void rcar_lvds_detach(struct drm_bridge *bridge)
-{
+	return drm_bridge_attach(bridge->encoder, lvds->next_bridge, bridge,
+				 flags);
 }
 
 static const struct drm_bridge_funcs rcar_lvds_bridge_ops = {
 	.attach = rcar_lvds_attach,
-	.detach = rcar_lvds_detach,
 	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
 	.atomic_reset = drm_atomic_helper_bridge_reset,
@@ -759,7 +654,7 @@ static int rcar_lvds_parse_dt_companion(struct rcar_lvds *lvds)
 		 * that we are expected to generate even pixels from the primary
 		 * encoder, and odd pixels from the companion encoder.
 		 */
-		if (lvds->next_bridge && lvds->next_bridge->timings &&
+		if (lvds->next_bridge->timings &&
 		    lvds->next_bridge->timings->dual_link)
 			lvds->link_type = RCAR_LVDS_DUAL_LINK_EVEN_ODD_PIXELS;
 		else
@@ -811,6 +706,15 @@ static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)
 	if (ret)
 		goto done;
 
+	if (lvds->panel) {
+		lvds->next_bridge = devm_drm_panel_bridge_add(lvds->dev,
+							      lvds->panel);
+		if (IS_ERR_OR_NULL(lvds->next_bridge)) {
+			ret = -EINVAL;
+			goto done;
+		}
+	}
+
 	if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK)
 		ret = rcar_lvds_parse_dt_companion(lvds);