drm/bridge: panel: Infer connector type from panel by default

The drm panel bridge creates a connector using a connector type
explicitly passed by the display controller or bridge driver that
instantiates the panel bridge. Now that drm_panel reports its connector
type, we can use it to avoid passing an explicit (and often incorrect)
connector type to drm_panel_bridge_add() and
devm_drm_panel_bridge_add().

Several drivers report incorrect or unknown connector types to
userspace. Reporting a different type may result in a breakage. For that
reason, rename (devm_)drm_panel_bridge_add() to
(devm_)drm_panel_bridge_add_typed(), and add new
(devm_)drm_panel_bridge_add() functions that use the panel connector
type. Update all callers of (devm_)drm_panel_bridge_add() to the _typed
function, they will be converted one by one after testing.

The panel drivers have been updated with the following Coccinelle
semantic patch, with manual inspection and fixes to indentation.

@@
expression bridge;
expression dev;
expression panel;
identifier type;
@@
(
-bridge = drm_panel_bridge_add(panel, type);
+bridge = drm_panel_bridge_add_typed(panel, type);
|
-bridge = devm_drm_panel_bridge_add(dev, panel, type);
+bridge = devm_drm_panel_bridge_add_typed(dev, panel, type);
)

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190904132804.29680-3-laurent.pinchart@ideasonboard.com

4 files changed, 64 insertions, 14 deletions

diff --git a/drivers/gpu/drm/bridge/cdns-dsi.c b/drivers/gpu/drm/bridge/cdns-dsi.c
index 6166dca6be81..3a5bd4e7fd1e 100644
--- a/drivers/gpu/drm/bridge/cdns-dsi.c
+++ b/drivers/gpu/drm/bridge/cdns-dsi.c
@@ -956,7 +956,8 @@ static int cdns_dsi_attach(struct mipi_dsi_host *host,
 
 	panel = of_drm_find_panel(np);
 	if (!IS_ERR(panel)) {
-		bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_DSI);
+		bridge = drm_panel_bridge_add_typed(panel,
+						    DRM_MODE_CONNECTOR_DSI);
 	} else {
 		bridge = of_drm_find_bridge(dev->dev.of_node);
 		if (!bridge)
diff --git a/drivers/gpu/drm/bridge/lvds-encoder.c b/drivers/gpu/drm/bridge/lvds-encoder.c
index 2ab2c234f26c..e2132a8d5106 100644
--- a/drivers/gpu/drm/bridge/lvds-encoder.c
+++ b/drivers/gpu/drm/bridge/lvds-encoder.c
@@ -106,7 +106,8 @@ static int lvds_encoder_probe(struct platform_device *pdev)
 	}
 
 	lvds_encoder->panel_bridge =
-		devm_drm_panel_bridge_add(dev, panel, DRM_MODE_CONNECTOR_LVDS);
+		devm_drm_panel_bridge_add_typed(dev, panel,
+						DRM_MODE_CONNECTOR_LVDS);
 	if (IS_ERR(lvds_encoder->panel_bridge))
 		return PTR_ERR(lvds_encoder->panel_bridge);
 
diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c
index 6cffeb4a42f2..f4e293e7cf64 100644
--- a/drivers/gpu/drm/bridge/panel.c
+++ b/drivers/gpu/drm/bridge/panel.c
@@ -134,8 +134,6 @@ static const struct drm_bridge_funcs panel_bridge_bridge_funcs = {
  * just calls the appropriate functions from &drm_panel.
  *
  * @panel: The drm_panel being wrapped.  Must be non-NULL.
- * @connector_type: The DRM_MODE_CONNECTOR_* for the connector to be
- * created.
  *
  * For drivers converting from directly using drm_panel: The expected
  * usage pattern is that during either encoder module probe or DSI
@@ -149,11 +147,37 @@ static const struct drm_bridge_funcs panel_bridge_bridge_funcs = {
  * drm_mode_config_cleanup() if the bridge has already been attached), then
  * drm_panel_bridge_remove() to free it.
  *
+ * The connector type is set to @panel->connector_type, which must be set to a
+ * known type. Calling this function with a panel whose connector type is
+ * DRM_MODE_CONNECTOR_Unknown will return NULL.
+ *
  * See devm_drm_panel_bridge_add() for an automatically manged version of this
  * function.
  */
-struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel,
-					u32 connector_type)
+struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel)
+{
+	if (WARN_ON(panel->connector_type == DRM_MODE_CONNECTOR_Unknown))
+		return NULL;
+
+	return drm_panel_bridge_add_typed(panel, panel->connector_type);
+}
+EXPORT_SYMBOL(drm_panel_bridge_add);
+
+/**
+ * drm_panel_bridge_add_typed - Creates a &drm_bridge and &drm_connector with
+ * an explicit connector type.
+ * @panel: The drm_panel being wrapped.  Must be non-NULL.
+ * @connector_type: The connector type (DRM_MODE_CONNECTOR_*)
+ *
+ * This is just like drm_panel_bridge_add(), but forces the connector type to
+ * @connector_type instead of infering it from the panel.
+ *
+ * This function is deprecated and should not be used in new drivers. Use
+ * drm_panel_bridge_add() instead, and fix panel drivers as necessary if they
+ * don't report a connector type.
+ */
+struct drm_bridge *drm_panel_bridge_add_typed(struct drm_panel *panel,
+					      u32 connector_type)
 {
 	struct panel_bridge *panel_bridge;
 
@@ -177,7 +201,7 @@ struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel,
 
 	return &panel_bridge->bridge;
 }
-EXPORT_SYMBOL(drm_panel_bridge_add);
+EXPORT_SYMBOL(drm_panel_bridge_add_typed);
 
 /**
  * drm_panel_bridge_remove - Unregisters and frees a drm_bridge
@@ -214,15 +238,38 @@ static void devm_drm_panel_bridge_release(struct device *dev, void *res)
  * that just calls the appropriate functions from &drm_panel.
  * @dev: device to tie the bridge lifetime to
  * @panel: The drm_panel being wrapped.  Must be non-NULL.
- * @connector_type: The DRM_MODE_CONNECTOR_* for the connector to be
- * created.
  *
  * This is the managed version of drm_panel_bridge_add() which automatically
  * calls drm_panel_bridge_remove() when @dev is unbound.
  */
 struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev,
-					     struct drm_panel *panel,
-					     u32 connector_type)
+					     struct drm_panel *panel)
+{
+	if (WARN_ON(panel->connector_type == DRM_MODE_CONNECTOR_Unknown))
+		return NULL;
+
+	return devm_drm_panel_bridge_add_typed(dev, panel,
+					       panel->connector_type);
+}
+EXPORT_SYMBOL(devm_drm_panel_bridge_add);
+
+/**
+ * devm_drm_panel_bridge_add_typed - Creates a managed &drm_bridge and
+ * &drm_connector with an explicit connector type.
+ * @dev: device to tie the bridge lifetime to
+ * @panel: The drm_panel being wrapped.  Must be non-NULL.
+ * @connector_type: The connector type (DRM_MODE_CONNECTOR_*)
+ *
+ * This is just like devm_drm_panel_bridge_add(), but forces the connector type
+ * to @connector_type instead of infering it from the panel.
+ *
+ * This function is deprecated and should not be used in new drivers. Use
+ * devm_drm_panel_bridge_add() instead, and fix panel drivers as necessary if
+ * they don't report a connector type.
+ */
+struct drm_bridge *devm_drm_panel_bridge_add_typed(struct device *dev,
+						   struct drm_panel *panel,
+						   u32 connector_type)
 {
 	struct drm_bridge **ptr, *bridge;
 
@@ -231,7 +278,7 @@ struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev,
 	if (!ptr)
 		return ERR_PTR(-ENOMEM);
 
-	bridge = drm_panel_bridge_add(panel, connector_type);
+	bridge = drm_panel_bridge_add_typed(panel, connector_type);
 	if (!IS_ERR(bridge)) {
 		*ptr = bridge;
 		devres_add(dev, ptr);
@@ -241,4 +288,4 @@ struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev,
 
 	return bridge;
 }
-EXPORT_SYMBOL(devm_drm_panel_bridge_add);
+EXPORT_SYMBOL(devm_drm_panel_bridge_add_typed);
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
index 675442bfc1bd..b8b1c288f663 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
@@ -316,7 +316,8 @@ static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
 		return ret;
 
 	if (panel) {
-		bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_DSI);
+		bridge = drm_panel_bridge_add_typed(panel,
+						    DRM_MODE_CONNECTOR_DSI);
 		if (IS_ERR(bridge))
 			return PTR_ERR(bridge);
 	}