[PATCH RFC v2 02/19] drm/bridge: panel: move to a new module

[Luca Ceresoli <luca.ceresoli@bootlin.com>]

Work is in progress for every drm_panel to embed a drm_bridge, which will
make the drm_panel code (currently in the drm module) depend on the
drm_kms_helper module.

However that would create a dependency loop:

 * the panel_bridge code in bridge/panel.c [drm_kms_helper module]
   already depends on the drm_panel.c code (it manipulates a drm_panel)
 * additionally, the drm_panel.c code, in order to create a drm_bridge,
   will depend on the helpers in drm_atomic_helper and drm_probe_helper
   code [drm_kms_helper module]

Prevent the loop by moving the panel bridge out to its own module.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 drivers/gpu/drm/Makefile       | 3 ++-
 drivers/gpu/drm/bridge/Kconfig | 2 +-
 drivers/gpu/drm/bridge/panel.c | 3 +++
 include/drm/drm_bridge.h       | 4 ++--
 4 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index e635fcffd379..c4509e7fd248 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -156,10 +156,11 @@ drm_kms_helper-y := \
 	drm_self_refresh_helper.o \
 	drm_simple_kms_helper.o \
 	drm_vblank_helper.o
-drm_kms_helper-$(CONFIG_DRM_PANEL_BRIDGE) += bridge/panel.o
 drm_kms_helper-$(CONFIG_DRM_FBDEV_EMULATION) += drm_fb_helper.o
 obj-$(CONFIG_DRM_KMS_HELPER) += drm_kms_helper.o
 
+obj-$(CONFIG_DRM_PANEL_BRIDGE) += bridge/panel.o
+
 #
 # Drivers and the rest
 #
diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index 89e87460aefc..0a1689f8209d 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -6,7 +6,7 @@ config DRM_BRIDGE
 	  Bridge registration and lookup framework.
 
 config DRM_PANEL_BRIDGE
-	def_bool y
+	def_tristate y
 	depends on DRM_BRIDGE
 	select DRM_PANEL
 	help
diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c
index 83be09641582..40e3970e8b76 100644
--- a/drivers/gpu/drm/bridge/panel.c
+++ b/drivers/gpu/drm/bridge/panel.c
@@ -624,3 +624,6 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
 EXPORT_SYMBOL_GPL(drm_of_find_panel_or_bridge);
 
 #endif
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Panel bridge helper");
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index c5b82e6946f5..9f2294957669 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -1473,7 +1473,7 @@ void drm_bridge_hpd_disable(struct drm_bridge *bridge);
 void drm_bridge_hpd_notify(struct drm_bridge *bridge,
 			   enum drm_connector_status status);
 
-#ifdef CONFIG_DRM_PANEL_BRIDGE
+#if IS_ENABLED(CONFIG_DRM_PANEL_BRIDGE)
 bool drm_bridge_is_panel(const struct drm_bridge *bridge);
 struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel);
 struct drm_bridge *drm_panel_bridge_add_typed(struct drm_panel *panel,
@@ -1502,7 +1502,7 @@ static inline int drm_panel_bridge_set_orientation(struct drm_connector *connect
 }
 #endif
 
-#if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL_BRIDGE)
+#if defined(CONFIG_OF) && IS_ENABLED(CONFIG_DRM_PANEL_BRIDGE)
 struct drm_bridge *devm_drm_of_get_bridge(struct device *dev, struct device_node *node,
 					  u32 port, u32 endpoint);
 struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm, struct device_node *node,

-- 
2.55.0