drm: Add __drm_atomic_helper_crtc_state_reset() & co.

Annoyingly __drm_atomic_helper_crtc_reset() does two
totally separate things:
a) reset the state to defaults values
b) assign the crtc->state pointer

I just want a) without the b) so let's split out part
a) into __drm_atomic_helper_crtc_state_reset(). And
of course we'll do the same thing for planes and connectors.

v2: Fix conn__state vs. conn_state typo (Lucas)
    Make code and kerneldoc match for
    __drm_atomic_helper_plane_state_reset()

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191107142417.11107-1-ville.syrjala@linux.intel.com
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_atomic_state_helper.c

@@ -57,6 +57,22 @@
  * for these functions.
  */
 
+/**
+ * __drm_atomic_helper_crtc_state_reset - reset the CRTC state
+ * @crtc_state: atomic CRTC state, must not be NULL
+ * @crtc: CRTC object, must not be NULL
+ *
+ * Initializes the newly allocated @crtc_state with default
+ * values. This is useful for drivers that subclass the CRTC state.
+ */
+void
+__drm_atomic_helper_crtc_state_reset(struct drm_crtc_state *crtc_state,
+				     struct drm_crtc *crtc)
+{
+	crtc_state->crtc = crtc;
+}
+EXPORT_SYMBOL(__drm_atomic_helper_crtc_state_reset);
+
 /**
  * __drm_atomic_helper_crtc_reset - reset state on CRTC
  * @crtc: drm CRTC
@@ -74,7 +90,7 @@ __drm_atomic_helper_crtc_reset(struct drm_crtc *crtc,
 			       struct drm_crtc_state *crtc_state)
 {
 	if (crtc_state)
-		crtc_state->crtc = crtc;
+		__drm_atomic_helper_crtc_state_reset(crtc_state, crtc);
 
 	crtc->state = crtc_state;
 }
@@ -212,23 +228,43 @@ void drm_atomic_helper_crtc_destroy_state(struct drm_crtc *crtc,
 EXPORT_SYMBOL(drm_atomic_helper_crtc_destroy_state);
 
 /**
- * __drm_atomic_helper_plane_reset - resets planes state to default values
+ * __drm_atomic_helper_plane_state_reset - resets plane state to default values
+ * @plane_state: atomic plane state, must not be NULL
  * @plane: plane object, must not be NULL
- * @state: atomic plane state, must not be NULL
  *
- * Initializes plane state to default. This is useful for drivers that subclass
- * the plane state.
+ * Initializes the newly allocated @plane_state with default
+ * values. This is useful for drivers that subclass the CRTC state.
+ */
+void __drm_atomic_helper_plane_state_reset(struct drm_plane_state *plane_state,
+					   struct drm_plane *plane)
+{
+	plane_state->plane = plane;
+	plane_state->rotation = DRM_MODE_ROTATE_0;
+
+	plane_state->alpha = DRM_BLEND_ALPHA_OPAQUE;
+	plane_state->pixel_blend_mode = DRM_MODE_BLEND_PREMULTI;
+}
+EXPORT_SYMBOL(__drm_atomic_helper_plane_state_reset);
+
+/**
+ * __drm_atomic_helper_plane_reset - reset state on plane
+ * @plane: drm plane
+ * @plane_state: plane state to assign
+ *
+ * Initializes the newly allocated @plane_state and assigns it to
+ * the &drm_crtc->state pointer of @plane, usually required when
+ * initializing the drivers or when called from the &drm_plane_funcs.reset
+ * hook.
+ *
+ * This is useful for drivers that subclass the plane state.
  */
 void __drm_atomic_helper_plane_reset(struct drm_plane *plane,
-				     struct drm_plane_state *state)
+				     struct drm_plane_state *plane_state)
 {
-	state->plane = plane;
-	state->rotation = DRM_MODE_ROTATE_0;
+	if (plane_state)
+		__drm_atomic_helper_plane_state_reset(plane_state, plane);
 
-	state->alpha = DRM_BLEND_ALPHA_OPAQUE;
-	state->pixel_blend_mode = DRM_MODE_BLEND_PREMULTI;
-
-	plane->state = state;
+	plane->state = plane_state;
 }
 EXPORT_SYMBOL(__drm_atomic_helper_plane_reset);
 
@@ -335,6 +371,22 @@ void drm_atomic_helper_plane_destroy_state(struct drm_plane *plane,
 }
 EXPORT_SYMBOL(drm_atomic_helper_plane_destroy_state);
 
+/**
+ * __drm_atomic_helper_connector_state_reset - reset the connector state
+ * @conn_state: atomic connector state, must not be NULL
+ * @connector: connectotr object, must not be NULL
+ *
+ * Initializes the newly allocated @conn_state with default
+ * values. This is useful for drivers that subclass the connector state.
+ */
+void
+__drm_atomic_helper_connector_state_reset(struct drm_connector_state *conn_state,
+					  struct drm_connector *connector)
+{
+	conn_state->connector = connector;
+}
+EXPORT_SYMBOL(__drm_atomic_helper_connector_state_reset);
+
 /**
  * __drm_atomic_helper_connector_reset - reset state on connector
  * @connector: drm connector
@@ -352,7 +404,7 @@ __drm_atomic_helper_connector_reset(struct drm_connector *connector,
 				    struct drm_connector_state *conn_state)
 {
 	if (conn_state)
-		conn_state->connector = connector;
+		__drm_atomic_helper_connector_state_reset(conn_state, connector);
 
 	connector->state = conn_state;
 }

include/drm/drm_atomic_state_helper.h

@@ -37,6 +37,8 @@ struct drm_private_state;
 struct drm_modeset_acquire_ctx;
 struct drm_device;
 
+void __drm_atomic_helper_crtc_state_reset(struct drm_crtc_state *state,
+					  struct drm_crtc *crtc);
 void __drm_atomic_helper_crtc_reset(struct drm_crtc *crtc,
 				    struct drm_crtc_state *state);
 void drm_atomic_helper_crtc_reset(struct drm_crtc *crtc);
@@ -48,6 +50,8 @@ void __drm_atomic_helper_crtc_destroy_state(struct drm_crtc_state *state);
 void drm_atomic_helper_crtc_destroy_state(struct drm_crtc *crtc,
 					  struct drm_crtc_state *state);
 
+void __drm_atomic_helper_plane_state_reset(struct drm_plane_state *state,
+					   struct drm_plane *plane);
 void __drm_atomic_helper_plane_reset(struct drm_plane *plane,
 				     struct drm_plane_state *state);
 void drm_atomic_helper_plane_reset(struct drm_plane *plane);
@@ -59,6 +63,8 @@ void __drm_atomic_helper_plane_destroy_state(struct drm_plane_state *state);
 void drm_atomic_helper_plane_destroy_state(struct drm_plane *plane,
 					  struct drm_plane_state *state);
 
+void __drm_atomic_helper_connector_state_reset(struct drm_connector_state *conn_state,
+					       struct drm_connector *connector);
 void __drm_atomic_helper_connector_reset(struct drm_connector *connector,
 					 struct drm_connector_state *conn_state);
 void drm_atomic_helper_connector_reset(struct drm_connector *connector);