drm/fb_cma_helper: add suspend helper

Implement a suspend/resume helper for CMA users which calls
drm_fb_helper_set_suspend.

Suggested-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Stefan Agner <stefan@agner.ch>

drivers/gpu/drm/drm_fb_cma_helper.c

@@ -582,3 +582,18 @@ void drm_fbdev_cma_hotplug_event(struct drm_fbdev_cma *fbdev_cma)
 		drm_fb_helper_hotplug_event(&fbdev_cma->fb_helper);
 }
 EXPORT_SYMBOL_GPL(drm_fbdev_cma_hotplug_event);
+
+/**
+ * drm_fbdev_cma_set_suspend - wrapper around drm_fb_helper_set_suspend
+ * @fbdev_cma: The drm_fbdev_cma struct, may be NULL
+ * @state: desired state, zero to resume, non-zero to suspend
+ *
+ * Calls drm_fb_helper_set_suspend, which is a wrapper around
+ * fb_set_suspend implemented by fbdev core.
+ */
+void drm_fbdev_cma_set_suspend(struct drm_fbdev_cma *fbdev_cma, int state)
+{
+	if (fbdev_cma)
+		drm_fb_helper_set_suspend(&fbdev_cma->fb_helper, state);
+}
+EXPORT_SYMBOL(drm_fbdev_cma_set_suspend);

include/drm/drm_fb_cma_helper.h

@@ -23,6 +23,7 @@ void drm_fbdev_cma_fini(struct drm_fbdev_cma *fbdev_cma);
 
 void drm_fbdev_cma_restore_mode(struct drm_fbdev_cma *fbdev_cma);
 void drm_fbdev_cma_hotplug_event(struct drm_fbdev_cma *fbdev_cma);
+void drm_fbdev_cma_set_suspend(struct drm_fbdev_cma *fbdev_cma, int state);
 int drm_fbdev_cma_create_with_funcs(struct drm_fb_helper *helper,
 	struct drm_fb_helper_surface_size *sizes,
 	const struct drm_framebuffer_funcs *funcs);