drm: atmel-hlcdc: rework the output code to support drm bridges

The current output code only supports connection to drm panels.
First simplify the drm panel code, and then add support for external drm
bridges.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Tested-by: Nicolas Ferre <nicolas.ferre@atmel.com>

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c

@@ -551,7 +551,7 @@ static int atmel_hlcdc_dc_modeset_init(struct drm_device *dev)
 
 	ret = atmel_hlcdc_create_outputs(dev);
 	if (ret) {
-		dev_err(dev->dev, "failed to create panel: %d\n", ret);
+		dev_err(dev->dev, "failed to create HLCDC outputs: %d\n", ret);
 		return ret;
 	}
 

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c

@@ -34,11 +34,13 @@
  * @connector: DRM connector
  * @encoder: DRM encoder
  * @dc: pointer to the atmel_hlcdc_dc structure
+ * @panel: panel connected on the RGB output
  */
 struct atmel_hlcdc_rgb_output {
 	struct drm_connector connector;
 	struct drm_encoder encoder;
 	struct atmel_hlcdc_dc *dc;
+	struct drm_panel *panel;
 };
 
 static inline struct atmel_hlcdc_rgb_output *
@@ -54,46 +56,31 @@ drm_encoder_to_atmel_hlcdc_rgb_output(struct drm_encoder *encoder)
 	return container_of(encoder, struct atmel_hlcdc_rgb_output, encoder);
 }
 
-/**
- * Atmel HLCDC Panel device structure
- *
- * This structure is specialization of the slave device structure to
- * interface with drm panels.
- *
- * @base: base slave device fields
- * @panel: drm panel attached to this slave device
- */
-struct atmel_hlcdc_panel {
-	struct atmel_hlcdc_rgb_output base;
-	struct drm_panel *panel;
-};
-
-static inline struct atmel_hlcdc_panel *
-atmel_hlcdc_rgb_output_to_panel(struct atmel_hlcdc_rgb_output *output)
-{
-	return container_of(output, struct atmel_hlcdc_panel, base);
-}
-
-static void atmel_hlcdc_panel_encoder_enable(struct drm_encoder *encoder)
+static void atmel_hlcdc_rgb_encoder_enable(struct drm_encoder *encoder)
 {
 	struct atmel_hlcdc_rgb_output *rgb =
 			drm_encoder_to_atmel_hlcdc_rgb_output(encoder);
-	struct atmel_hlcdc_panel *panel = atmel_hlcdc_rgb_output_to_panel(rgb);
-	drm_panel_enable(panel->panel);
+
+	if (rgb->panel) {
+		drm_panel_prepare(rgb->panel);
+		drm_panel_enable(rgb->panel);
+	}
 }
 
-static void atmel_hlcdc_panel_encoder_disable(struct drm_encoder *encoder)
+static void atmel_hlcdc_rgb_encoder_disable(struct drm_encoder *encoder)
 {
 	struct atmel_hlcdc_rgb_output *rgb =
 			drm_encoder_to_atmel_hlcdc_rgb_output(encoder);
-	struct atmel_hlcdc_panel *panel = atmel_hlcdc_rgb_output_to_panel(rgb);
 
-	drm_panel_disable(panel->panel);
+	if (rgb->panel) {
+		drm_panel_disable(rgb->panel);
+		drm_panel_unprepare(rgb->panel);
+	}
 }
 
 static const struct drm_encoder_helper_funcs atmel_hlcdc_panel_encoder_helper_funcs = {
-	.disable = atmel_hlcdc_panel_encoder_disable,
-	.enable = atmel_hlcdc_panel_encoder_enable,
+	.disable = atmel_hlcdc_rgb_encoder_disable,
+	.enable = atmel_hlcdc_rgb_encoder_enable,
 };
 
 static void atmel_hlcdc_rgb_encoder_destroy(struct drm_encoder *encoder)
@@ -110,9 +97,11 @@ static int atmel_hlcdc_panel_get_modes(struct drm_connector *connector)
 {
 	struct atmel_hlcdc_rgb_output *rgb =
 			drm_connector_to_atmel_hlcdc_rgb_output(connector);
-	struct atmel_hlcdc_panel *panel = atmel_hlcdc_rgb_output_to_panel(rgb);
 
-	return panel->panel->funcs->get_modes(panel->panel);
+	if (rgb->panel)
+		return rgb->panel->funcs->get_modes(rgb->panel);
+
+	return 0;
 }
 
 static int atmel_hlcdc_rgb_mode_valid(struct drm_connector *connector,
@@ -144,7 +133,13 @@ static const struct drm_connector_helper_funcs atmel_hlcdc_panel_connector_helpe
 static enum drm_connector_status
 atmel_hlcdc_panel_connector_detect(struct drm_connector *connector, bool force)
 {
-	return connector_status_connected;
+	struct atmel_hlcdc_rgb_output *rgb =
+			drm_connector_to_atmel_hlcdc_rgb_output(connector);
+
+	if (rgb->panel)
+		return connector_status_connected;
+
+	return connector_status_disconnected;
 }
 
 static void
@@ -152,9 +147,10 @@ atmel_hlcdc_panel_connector_destroy(struct drm_connector *connector)
 {
 	struct atmel_hlcdc_rgb_output *rgb =
 			drm_connector_to_atmel_hlcdc_rgb_output(connector);
-	struct atmel_hlcdc_panel *panel = atmel_hlcdc_rgb_output_to_panel(rgb);
 
-	drm_panel_detach(panel->panel);
+	if (rgb->panel)
+		drm_panel_detach(rgb->panel);
+
 	drm_connector_cleanup(connector);
 }
 
@@ -168,87 +164,122 @@ static const struct drm_connector_funcs atmel_hlcdc_panel_connector_funcs = {
 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 };
 
-static int atmel_hlcdc_create_panel_output(struct drm_device *dev,
-					   struct of_endpoint *ep)
+static int atmel_hlcdc_check_endpoint(struct drm_device *dev,
+				      const struct of_endpoint *ep)
 {
-	struct atmel_hlcdc_dc *dc = dev->dev_private;
 	struct device_node *np;
-	struct drm_panel *p = NULL;
-	struct atmel_hlcdc_panel *panel;
-	int ret;
+	void *obj;
 
 	np = of_graph_get_remote_port_parent(ep->local_node);
-	if (!np)
-		return -EINVAL;
 
-	p = of_drm_find_panel(np);
+	obj = of_drm_find_panel(np);
+	if (!obj)
+		obj = of_drm_find_bridge(np);
+
 	of_node_put(np);
 
-	if (!p)
-		return -EPROBE_DEFER;
+	return obj ? 0 : -EPROBE_DEFER;
+}
 
-	panel = devm_kzalloc(dev->dev, sizeof(*panel), GFP_KERNEL);
-	if (!panel)
-		return -EINVAL;
+static int atmel_hlcdc_attach_endpoint(struct drm_device *dev,
+				       const struct of_endpoint *ep)
+{
+	struct atmel_hlcdc_dc *dc = dev->dev_private;
+	struct atmel_hlcdc_rgb_output *output;
+	struct device_node *np;
+	struct drm_panel *panel;
+	struct drm_bridge *bridge;
+	int ret;
 
+	output = devm_kzalloc(dev->dev, sizeof(*output), GFP_KERNEL);
+	if (!output)
+		return -EINVAL;
 
-	panel->base.dc = dc;
+	output->dc = dc;
 
-	drm_encoder_helper_add(&panel->base.encoder,
+	drm_encoder_helper_add(&output->encoder,
 			       &atmel_hlcdc_panel_encoder_helper_funcs);
-	ret = drm_encoder_init(dev, &panel->base.encoder,
+	ret = drm_encoder_init(dev, &output->encoder,
 			       &atmel_hlcdc_panel_encoder_funcs,
 			       DRM_MODE_ENCODER_NONE, NULL);
 	if (ret)
 		return ret;
 
-	panel->base.connector.dpms = DRM_MODE_DPMS_OFF;
-	panel->base.connector.polled = DRM_CONNECTOR_POLL_CONNECT;
-	drm_connector_helper_add(&panel->base.connector,
-				 &atmel_hlcdc_panel_connector_helper_funcs);
-	ret = drm_connector_init(dev, &panel->base.connector,
-				 &atmel_hlcdc_panel_connector_funcs,
-				 DRM_MODE_CONNECTOR_Unknown);
-	if (ret)
-		goto err_encoder_cleanup;
+	output->encoder.possible_crtcs = 0x1;
+
+	np = of_graph_get_remote_port_parent(ep->local_node);
 
-	drm_mode_connector_attach_encoder(&panel->base.connector,
-					  &panel->base.encoder);
-	panel->base.encoder.possible_crtcs = 0x1;
+	ret = -EPROBE_DEFER;
 
-	drm_panel_attach(p, &panel->base.connector);
-	panel->panel = p;
+	panel = of_drm_find_panel(np);
+	if (panel) {
+		of_node_put(np);
+		output->connector.dpms = DRM_MODE_DPMS_OFF;
+		output->connector.polled = DRM_CONNECTOR_POLL_CONNECT;
+		drm_connector_helper_add(&output->connector,
+				&atmel_hlcdc_panel_connector_helper_funcs);
+		ret = drm_connector_init(dev, &output->connector,
+					 &atmel_hlcdc_panel_connector_funcs,
+					 DRM_MODE_CONNECTOR_Unknown);
+		if (ret)
+			goto err_encoder_cleanup;
 
-	return 0;
+		drm_mode_connector_attach_encoder(&output->connector,
+						  &output->encoder);
+
+		ret = drm_panel_attach(panel, &output->connector);
+		if (ret) {
+			drm_connector_cleanup(&output->connector);
+			goto err_encoder_cleanup;
+		}
+
+		output->panel = panel;
+
+		return 0;
+	}
+
+	bridge = of_drm_find_bridge(np);
+	of_node_put(np);
+
+	if (bridge) {
+		output->encoder.bridge = bridge;
+		bridge->encoder = &output->encoder;
+		ret = drm_bridge_attach(dev, bridge);
+		if (!ret)
+			return 0;
+	}
 
 err_encoder_cleanup:
-	drm_encoder_cleanup(&panel->base.encoder);
+	drm_encoder_cleanup(&output->encoder);
 
 	return ret;
 }
 
 int atmel_hlcdc_create_outputs(struct drm_device *dev)
 {
-	struct device_node *port_np, *np;
+	struct device_node *ep_np = NULL;
 	struct of_endpoint ep;
 	int ret;
 
-	port_np = of_get_child_by_name(dev->dev->of_node, "port");
-	if (!port_np)
-		return -EINVAL;
+	for_each_endpoint_of_node(dev->dev->of_node, ep_np) {
+		ret = of_graph_parse_endpoint(ep_np, &ep);
+		if (!ret)
+			ret = atmel_hlcdc_check_endpoint(dev, &ep);
 
-	np = of_get_child_by_name(port_np, "endpoint");
-	of_node_put(port_np);
+		of_node_put(ep_np);
+		if (ret)
+			return ret;
+	}
 
-	if (!np)
-		return -EINVAL;
+	for_each_endpoint_of_node(dev->dev->of_node, ep_np) {
+		ret = of_graph_parse_endpoint(ep_np, &ep);
+		if (!ret)
+			ret = atmel_hlcdc_attach_endpoint(dev, &ep);
 
-	ret = of_graph_parse_endpoint(np, &ep);
-	of_node_put(port_np);
+		of_node_put(ep_np);
+		if (ret)
+			return ret;
+	}
 
-	if (ret)
-		return ret;
-
-	/* We currently only support panel output */
-	return atmel_hlcdc_create_panel_output(dev, &ep);
+	return 0;
 }