drm/crtc: Introduce drmm_crtc_init_with_planes

The DRM-managed function to register a CRTC is
drmm_crtc_alloc_with_planes(), which will allocate the underlying
structure and initialisation the CRTC.

However, we might want to separate the structure creation and the CRTC
initialisation, for example if the structure is shared across multiple
DRM entities, for example an encoder and a connector.

Let's create an helper to only initialise a CRTC that would be passed as
an argument.
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220711173939.1132294-3-maxime@cerno.tech

drivers/gpu/drm/drm_crtc.c

@@ -343,9 +343,10 @@ static int __drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *
  * The @primary and @cursor planes are only relevant for legacy uAPI, see
  * &drm_crtc.primary and &drm_crtc.cursor.
  *
- * Note: consider using drmm_crtc_alloc_with_planes() instead of
- * drm_crtc_init_with_planes() to let the DRM managed resource infrastructure
- * take care of cleanup and deallocation.
+ * Note: consider using drmm_crtc_alloc_with_planes() or
+ * drmm_crtc_init_with_planes() instead of drm_crtc_init_with_planes()
+ * to let the DRM managed resource infrastructure take care of cleanup
+ * and deallocation.
  *
  * Returns:
  * Zero on success, error code on failure.
@@ -370,14 +371,88 @@ int drm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
 }
 EXPORT_SYMBOL(drm_crtc_init_with_planes);
 
-static void drmm_crtc_alloc_with_planes_cleanup(struct drm_device *dev,
-						void *ptr)
+static void drmm_crtc_init_with_planes_cleanup(struct drm_device *dev,
+					       void *ptr)
 {
 	struct drm_crtc *crtc = ptr;
 
 	drm_crtc_cleanup(crtc);
 }
 
+__printf(6, 0)
+static int __drmm_crtc_init_with_planes(struct drm_device *dev,
+					struct drm_crtc *crtc,
+					struct drm_plane *primary,
+					struct drm_plane *cursor,
+					const struct drm_crtc_funcs *funcs,
+					const char *name,
+					va_list args)
+{
+	int ret;
+
+	drm_WARN_ON(dev, funcs && funcs->destroy);
+
+	ret = __drm_crtc_init_with_planes(dev, crtc, primary, cursor, funcs,
+					  name, args);
+	if (ret)
+		return ret;
+
+	ret = drmm_add_action_or_reset(dev, drmm_crtc_init_with_planes_cleanup,
+				       crtc);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+/**
+ * drmm_crtc_init_with_planes - Initialise a new CRTC object with
+ *    specified primary and cursor planes.
+ * @dev: DRM device
+ * @crtc: CRTC object to init
+ * @primary: Primary plane for CRTC
+ * @cursor: Cursor plane for CRTC
+ * @funcs: callbacks for the new CRTC
+ * @name: printf style format string for the CRTC name, or NULL for default name
+ *
+ * Inits a new object created as base part of a driver crtc object. Drivers
+ * should use this function instead of drm_crtc_init(), which is only provided
+ * for backwards compatibility with drivers which do not yet support universal
+ * planes). For really simple hardware which has only 1 plane look at
+ * drm_simple_display_pipe_init() instead.
+ *
+ * Cleanup is automatically handled through registering
+ * drmm_crtc_cleanup() with drmm_add_action(). The crtc structure should
+ * be allocated with drmm_kzalloc().
+ *
+ * The @drm_crtc_funcs.destroy hook must be NULL.
+ *
+ * The @primary and @cursor planes are only relevant for legacy uAPI, see
+ * &drm_crtc.primary and &drm_crtc.cursor.
+ *
+ * Returns:
+ * Zero on success, error code on failure.
+ */
+int drmm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
+			       struct drm_plane *primary,
+			       struct drm_plane *cursor,
+			       const struct drm_crtc_funcs *funcs,
+			       const char *name, ...)
+{
+	va_list ap;
+	int ret;
+
+	va_start(ap, name);
+	ret = __drmm_crtc_init_with_planes(dev, crtc, primary, cursor, funcs,
+					   name, ap);
+	va_end(ap);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL(drmm_crtc_init_with_planes);
+
 void *__drmm_crtc_alloc_with_planes(struct drm_device *dev,
 				    size_t size, size_t offset,
 				    struct drm_plane *primary,
@@ -400,17 +475,12 @@ void *__drmm_crtc_alloc_with_planes(struct drm_device *dev,
 	crtc = container + offset;
 
 	va_start(ap, name);
-	ret = __drm_crtc_init_with_planes(dev, crtc, primary, cursor, funcs,
-					  name, ap);
+	ret = __drmm_crtc_init_with_planes(dev, crtc, primary, cursor, funcs,
+					   name, ap);
 	va_end(ap);
 	if (ret)
 		return ERR_PTR(ret);
 
-	ret = drmm_add_action_or_reset(dev, drmm_crtc_alloc_with_planes_cleanup,
-				       crtc);
-	if (ret)
-		return ERR_PTR(ret);
-
 	return container;
 }
 EXPORT_SYMBOL(__drmm_crtc_alloc_with_planes);

include/drm/drm_crtc.h

@@ -1216,6 +1216,15 @@ int drm_crtc_init_with_planes(struct drm_device *dev,
 			      struct drm_plane *cursor,
 			      const struct drm_crtc_funcs *funcs,
 			      const char *name, ...);
+
+__printf(6, 7)
+int drmm_crtc_init_with_planes(struct drm_device *dev,
+			       struct drm_crtc *crtc,
+			       struct drm_plane *primary,
+			       struct drm_plane *cursor,
+			       const struct drm_crtc_funcs *funcs,
+			       const char *name, ...);
+
 void drm_crtc_cleanup(struct drm_crtc *crtc);
 
 __printf(7, 8)