drm: exynos: dsi: Convert to bridge driver

Some display panels would come up with a non-DSI output, those
can have an option to connect the DSI host by means of interface
bridge converter.

This DSI to non-DSI interface bridge converter would requires
DSI Host to handle drm bridge functionalities in order to DSI
Host to Interface bridge.

This patch convert the existing to a drm bridge driver with a
built-in encoder support for compatibility with existing
component drivers.
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211122070633.89219-2-jagan@amarulasolutions.com

drivers/gpu/drm/exynos/exynos_drm_dsi.c

@@ -257,6 +257,7 @@ struct exynos_dsi {
 	struct drm_connector connector;
 	struct drm_panel *panel;
 	struct list_head bridge_chain;
+	struct drm_bridge bridge;
 	struct drm_bridge *out_bridge;
 	struct device *dev;
 
@@ -287,9 +288,9 @@ struct exynos_dsi {
 #define host_to_dsi(host) container_of(host, struct exynos_dsi, dsi_host)
 #define connector_to_dsi(c) container_of(c, struct exynos_dsi, connector)
 
-static inline struct exynos_dsi *encoder_to_dsi(struct drm_encoder *e)
+static inline struct exynos_dsi *bridge_to_dsi(struct drm_bridge *b)
 {
-	return container_of(e, struct exynos_dsi, encoder);
+	return container_of(b, struct exynos_dsi, bridge);
 }
 
 enum reg_idx {
@@ -1374,9 +1375,10 @@ static void exynos_dsi_unregister_te_irq(struct exynos_dsi *dsi)
 	}
 }
 
-static void exynos_dsi_enable(struct drm_encoder *encoder)
+static void exynos_dsi_atomic_enable(struct drm_bridge *bridge,
+				     struct drm_bridge_state *old_bridge_state)
 {
-	struct exynos_dsi *dsi = encoder_to_dsi(encoder);
+	struct exynos_dsi *dsi = bridge_to_dsi(bridge);
 	struct drm_bridge *iter;
 	int ret;
 
@@ -1399,7 +1401,8 @@ static void exynos_dsi_enable(struct drm_encoder *encoder)
 		list_for_each_entry_reverse(iter, &dsi->bridge_chain,
 					    chain_node) {
 			if (iter->funcs->pre_enable)
-				iter->funcs->pre_enable(iter);
+				iter->funcs->atomic_pre_enable(iter,
+							       old_bridge_state);
 		}
 	}
 
@@ -1413,7 +1416,7 @@ static void exynos_dsi_enable(struct drm_encoder *encoder)
 	} else {
 		list_for_each_entry(iter, &dsi->bridge_chain, chain_node) {
 			if (iter->funcs->enable)
-				iter->funcs->enable(iter);
+				iter->funcs->atomic_enable(iter, old_bridge_state);
 		}
 	}
 
@@ -1429,9 +1432,10 @@ static void exynos_dsi_enable(struct drm_encoder *encoder)
 	pm_runtime_put(dsi->dev);
 }
 
-static void exynos_dsi_disable(struct drm_encoder *encoder)
+static void exynos_dsi_atomic_disable(struct drm_bridge *bridge,
+				      struct drm_bridge_state *old_bridge_state)
 {
-	struct exynos_dsi *dsi = encoder_to_dsi(encoder);
+	struct exynos_dsi *dsi = bridge_to_dsi(bridge);
 	struct drm_bridge *iter;
 
 	if (!(dsi->state & DSIM_STATE_ENABLED))
@@ -1443,7 +1447,7 @@ static void exynos_dsi_disable(struct drm_encoder *encoder)
 
 	list_for_each_entry_reverse(iter, &dsi->bridge_chain, chain_node) {
 		if (iter->funcs->disable)
-			iter->funcs->disable(iter);
+			iter->funcs->atomic_disable(iter, old_bridge_state);
 	}
 
 	exynos_dsi_set_display_enable(dsi, false);
@@ -1451,7 +1455,7 @@ static void exynos_dsi_disable(struct drm_encoder *encoder)
 
 	list_for_each_entry(iter, &dsi->bridge_chain, chain_node) {
 		if (iter->funcs->post_disable)
-			iter->funcs->post_disable(iter);
+			iter->funcs->atomic_post_disable(iter, old_bridge_state);
 	}
 
 	dsi->state &= ~DSIM_STATE_ENABLED;
@@ -1494,9 +1498,9 @@ static const struct drm_connector_helper_funcs exynos_dsi_connector_helper_funcs
 	.get_modes = exynos_dsi_get_modes,
 };
 
-static int exynos_dsi_create_connector(struct drm_encoder *encoder)
+static int exynos_dsi_create_connector(struct exynos_dsi *dsi)
 {
-	struct exynos_dsi *dsi = encoder_to_dsi(encoder);
+	struct drm_encoder *encoder = &dsi->encoder;
 	struct drm_connector *connector = &dsi->connector;
 	struct drm_device *drm = encoder->dev;
 	int ret;
@@ -1522,9 +1526,21 @@ static int exynos_dsi_create_connector(struct drm_encoder *encoder)
 	return 0;
 }
 
-static const struct drm_encoder_helper_funcs exynos_dsi_encoder_helper_funcs = {
-	.enable = exynos_dsi_enable,
-	.disable = exynos_dsi_disable,
+static int exynos_dsi_attach(struct drm_bridge *bridge,
+			     enum drm_bridge_attach_flags flags)
+{
+	struct exynos_dsi *dsi = bridge_to_dsi(bridge);
+
+	return drm_bridge_attach(bridge->encoder, dsi->out_bridge, NULL, 0);
+}
+
+static const struct drm_bridge_funcs exynos_dsi_bridge_funcs = {
+	.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,
+	.atomic_enable		= exynos_dsi_atomic_enable,
+	.atomic_disable		= exynos_dsi_atomic_disable,
+	.attach			= exynos_dsi_attach,
 };
 
 MODULE_DEVICE_TABLE(of, exynos_dsi_of_match);
@@ -1543,7 +1559,7 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
 		dsi->out_bridge = out_bridge;
 		list_splice_init(&encoder->bridge_chain, &dsi->bridge_chain);
 	} else {
-		int ret = exynos_dsi_create_connector(encoder);
+		int ret = exynos_dsi_create_connector(dsi);
 
 		if (ret) {
 			DRM_DEV_ERROR(dsi->dev,
@@ -1596,7 +1612,7 @@ static int exynos_dsi_host_detach(struct mipi_dsi_host *host,
 
 	if (dsi->panel) {
 		mutex_lock(&drm->mode_config.mutex);
-		exynos_dsi_disable(&dsi->encoder);
+		exynos_dsi_atomic_disable(&dsi->bridge, NULL);
 		dsi->panel = NULL;
 		dsi->connector.status = connector_status_disconnected;
 		mutex_unlock(&drm->mode_config.mutex);
@@ -1702,12 +1718,16 @@ static int exynos_dsi_bind(struct device *dev, struct device *master,
 
 	drm_simple_encoder_init(drm_dev, encoder, DRM_MODE_ENCODER_TMDS);
 
-	drm_encoder_helper_add(encoder, &exynos_dsi_encoder_helper_funcs);
-
 	ret = exynos_drm_set_possible_crtcs(encoder, EXYNOS_DISPLAY_TYPE_LCD);
 	if (ret < 0)
 		return ret;
 
+	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL, 0);
+	if (ret) {
+		drm_encoder_cleanup(&dsi->encoder);
+		return ret;
+	}
+
 	in_bridge_node = of_graph_get_remote_node(dev->of_node, DSI_PORT_IN, 0);
 	if (in_bridge_node) {
 		in_bridge = of_drm_find_bridge(in_bridge_node);
@@ -1723,10 +1743,9 @@ static void exynos_dsi_unbind(struct device *dev, struct device *master,
 				void *data)
 {
 	struct exynos_dsi *dsi = dev_get_drvdata(dev);
-	struct drm_encoder *encoder = &dsi->encoder;
-
-	exynos_dsi_disable(encoder);
 
+	exynos_dsi_atomic_disable(&dsi->bridge, NULL);
+	drm_encoder_cleanup(&dsi->encoder);
 	mipi_dsi_host_unregister(&dsi->dsi_host);
 }
 
@@ -1819,6 +1838,12 @@ static int exynos_dsi_probe(struct platform_device *pdev)
 
 	pm_runtime_enable(dev);
 
+	dsi->bridge.funcs = &exynos_dsi_bridge_funcs;
+	dsi->bridge.of_node = dev->of_node;
+	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
+
+	drm_bridge_add(&dsi->bridge);
+
 	ret = component_add(dev, &exynos_dsi_component_ops);
 	if (ret)
 		goto err_disable_runtime;
@@ -1833,6 +1858,10 @@ static int exynos_dsi_probe(struct platform_device *pdev)
 
 static int exynos_dsi_remove(struct platform_device *pdev)
 {
+	struct exynos_dsi *dsi = platform_get_drvdata(pdev);
+
+	drm_bridge_remove(&dsi->bridge);
+
 	pm_runtime_disable(&pdev->dev);
 
 	component_del(&pdev->dev, &exynos_dsi_component_ops);