drm/bridge: Make (pre/post) enable/disable callbacks optional

Instead of forcing bridges to implement empty callbacks make them all
optional.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

2 files changed, 16 insertions, 4 deletions

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index bd93453afa61..b3654404abd0 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -186,7 +186,8 @@ void drm_bridge_disable(struct drm_bridge *bridge)
 
         drm_bridge_disable(bridge->next);
 
-        bridge->funcs->disable(bridge);
+        if (bridge->funcs->disable)
+                bridge->funcs->disable(bridge);
 }
 EXPORT_SYMBOL(drm_bridge_disable);
 
@@ -206,7 +207,8 @@ void drm_bridge_post_disable(struct drm_bridge *bridge)
         if (!bridge)
                 return;
 
-        bridge->funcs->post_disable(bridge);
+        if (bridge->funcs->post_disable)
+                bridge->funcs->post_disable(bridge);
 
         drm_bridge_post_disable(bridge->next);
 }
@@ -256,7 +258,8 @@ void drm_bridge_pre_enable(struct drm_bridge *bridge)
 
         drm_bridge_pre_enable(bridge->next);
 
-        bridge->funcs->pre_enable(bridge);
+        if (bridge->funcs->pre_enable)
+                bridge->funcs->pre_enable(bridge);
 }
 EXPORT_SYMBOL(drm_bridge_pre_enable);
 
@@ -276,7 +279,8 @@ void drm_bridge_enable(struct drm_bridge *bridge)
         if (!bridge)
                 return;
 
-        bridge->funcs->enable(bridge);
+        if (bridge->funcs->enable)
+                bridge->funcs->enable(bridge);
 
         drm_bridge_enable(bridge->next);
 }
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index c65a212db77e..f336671ca932 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1581,6 +1581,8 @@ struct drm_bridge_funcs {
          *
          * The bridge can assume that the display pipe (i.e. clocks and timing
          * signals) feeding it is still running when this callback is called.
+         *
+         * The disable callback is optional.
          */
         void (*disable)(struct drm_bridge *bridge);
 
@@ -1597,6 +1599,8 @@ struct drm_bridge_funcs {
          * The bridge must assume that the display pipe (i.e. clocks and timing
          * singals) feeding it is no longer running when this callback is
          * called.
+         *
+         * The post_disable callback is optional.
          */
         void (*post_disable)(struct drm_bridge *bridge);
 
@@ -1625,6 +1629,8 @@ struct drm_bridge_funcs {
          * will not yet be running when this callback is called. The bridge must
          * not enable the display link feeding the next bridge in the chain (if
          * there is one) when this callback is called.
+         *
+         * The pre_enable callback is optional.
          */
         void (*pre_enable)(struct drm_bridge *bridge);
 
@@ -1642,6 +1648,8 @@ struct drm_bridge_funcs {
          * signals) feeding it is running when this callback is called. This
          * callback must enable the display link feeding the next bridge in the
          * chain if there is one.
+         *
+         * The enable callback is optional.
          */
         void (*enable)(struct drm_bridge *bridge);
 };