drm/simple_kms_helper: Add {enable|disable}_vblank callback support

If simple_kms_helper based driver needs to work with vblanks,
then it has to provide drm_driver.{enable|disable}_vblank callbacks,
because drm_simple_kms_helper.drm_crtc_funcs does not provide any.
At the same time drm_driver.{enable|disable}_vblank callbacks
are marked as deprecated and shouldn't be used by new drivers.

Fix this by extending drm_simple_kms_helper.drm_crtc_funcs
to provide the missing callbacks.
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1518425574-32671-2-git-send-email-andr2000@gmail.com

drivers/gpu/drm/drm_simple_kms_helper.c

@@ -92,6 +92,28 @@ static const struct drm_crtc_helper_funcs drm_simple_kms_crtc_helper_funcs = {
 	.atomic_disable = drm_simple_kms_crtc_disable,
 };
 
+static int drm_simple_kms_crtc_enable_vblank(struct drm_crtc *crtc)
+{
+	struct drm_simple_display_pipe *pipe;
+
+	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
+	if (!pipe->funcs || !pipe->funcs->enable_vblank)
+		return 0;
+
+	return pipe->funcs->enable_vblank(pipe);
+}
+
+static void drm_simple_kms_crtc_disable_vblank(struct drm_crtc *crtc)
+{
+	struct drm_simple_display_pipe *pipe;
+
+	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
+	if (!pipe->funcs || !pipe->funcs->disable_vblank)
+		return;
+
+	pipe->funcs->disable_vblank(pipe);
+}
+
 static const struct drm_crtc_funcs drm_simple_kms_crtc_funcs = {
 	.reset = drm_atomic_helper_crtc_reset,
 	.destroy = drm_crtc_cleanup,
@@ -99,6 +121,8 @@ static const struct drm_crtc_funcs drm_simple_kms_crtc_funcs = {
 	.page_flip = drm_atomic_helper_page_flip,
 	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
+	.enable_vblank = drm_simple_kms_crtc_enable_vblank,
+	.disable_vblank = drm_simple_kms_crtc_disable_vblank,
 };
 
 static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane,

include/drm/drm_simple_kms_helper.h

@@ -107,6 +107,24 @@ struct drm_simple_display_pipe_funcs {
 	 */
 	void (*cleanup_fb)(struct drm_simple_display_pipe *pipe,
 			   struct drm_plane_state *plane_state);
+
+	/**
+	 * @enable_vblank:
+	 *
+	 * Optional, called by &drm_crtc_funcs.enable_vblank. Please read
+	 * the documentation for the &drm_crtc_funcs.enable_vblank hook for
+	 * more details.
+	 */
+	int (*enable_vblank)(struct drm_simple_display_pipe *pipe);
+
+	/**
+	 * @disable_vblank:
+	 *
+	 * Optional, called by &drm_crtc_funcs.disable_vblank. Please read
+	 * the documentation for the &drm_crtc_funcs.disable_vblank hook for
+	 * more details.
+	 */
+	void (*disable_vblank)(struct drm_simple_display_pipe *pipe);
 };
 
 /**