[PATCH] drm/rockchip: return ERR_PTR instead of NULL

[Julia Lawall]

rockchip_drm_framebuffer_init is only used in one case, in
rockchip_drm_fbdev.c, where its return value is tested using IS_ERR.  To
enable propagating the reason for the error, change the definition so that
it returns an ERR_PTR value.

Problem found with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxx>

---
 drivers/gpu/drm/rockchip/rockchip_drm_fb.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
index 0f6eda0..01e11bf 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_fb.c
@@ -213,7 +213,7 @@ struct drm_framebuffer *
 
 	rockchip_fb = rockchip_fb_alloc(dev, mode_cmd, &obj, 1);
 	if (IS_ERR(rockchip_fb))
-		return NULL;
+		return ERR_CAST(rockchip_fb);
 
 	return &rockchip_fb->fb;
 }