drm/ast: use container_of to resolve ast_fbdev from drm_fb_helper

Use container_of instead of casting first structure member.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/gpu/drm/ast/ast_fb.c b/drivers/gpu/drm/ast/ast_fb.c
index cba45c774552..5c60ae524c45 100644
--- a/drivers/gpu/drm/ast/ast_fb.c
+++ b/drivers/gpu/drm/ast/ast_fb.c
@@ -186,7 +186,8 @@ static int astfb_create_object(struct ast_fbdev *afbdev,
 static int astfb_create(struct drm_fb_helper *helper,
                         struct drm_fb_helper_surface_size *sizes)
 {
-        struct ast_fbdev *afbdev = (struct ast_fbdev *)helper;
+        struct ast_fbdev *afbdev =
+                container_of(helper, struct ast_fbdev, helper);
         struct drm_device *dev = afbdev->helper.dev;
         struct drm_mode_fb_cmd2 mode_cmd;
         struct drm_framebuffer *fb;