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>
Link: http://patchwork.freedesktop.org/patch/msgid/1456480266-7904-1-git-send-email-laurent.pinchart+renesas@ideasonboard.com
Acked-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index b10eba23a744..f048a7b06529 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1596,6 +1596,8 @@ 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);
 
@@ -1612,6 +1614,8 @@ 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);
 
@@ -1640,6 +1644,8 @@ 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);
 
@@ -1657,6 +1663,8 @@ 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);
 };