drm/exynos: add atomic_check callback to exynos_crtc

Some CRTCs needs mode validation, this patch adds neccessary
callback to Exynos DRM framework. It is called from DRM core
via atomic_check helper for drm_crtc.
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_crtc.c

@@ -50,6 +50,17 @@ exynos_drm_crtc_mode_set_nofb(struct drm_crtc *crtc)
 		exynos_crtc->ops->commit(exynos_crtc);
 }
 
+static int exynos_crtc_atomic_check(struct drm_crtc *crtc,
+				     struct drm_crtc_state *state)
+{
+	struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(crtc);
+
+	if (exynos_crtc->ops->atomic_check)
+		return exynos_crtc->ops->atomic_check(exynos_crtc, state);
+
+	return 0;
+}
+
 static void exynos_crtc_atomic_begin(struct drm_crtc *crtc,
 				     struct drm_crtc_state *old_crtc_state)
 {
@@ -86,6 +97,7 @@ static struct drm_crtc_helper_funcs exynos_crtc_helper_funcs = {
 	.enable		= exynos_drm_crtc_enable,
 	.disable	= exynos_drm_crtc_disable,
 	.mode_set_nofb	= exynos_drm_crtc_mode_set_nofb,
+	.atomic_check	= exynos_crtc_atomic_check,
 	.atomic_begin	= exynos_crtc_atomic_begin,
 	.atomic_flush	= exynos_crtc_atomic_flush,
 };

drivers/gpu/drm/exynos/exynos_drm_drv.h

@@ -89,6 +89,7 @@ struct exynos_drm_plane {
  * @disable_vblank: specific driver callback for disabling vblank interrupt.
  * @wait_for_vblank: wait for vblank interrupt to make sure that
  *	hardware overlay is updated.
+ * @atomic_check: validate state
  * @atomic_begin: prepare a window to receive a update
  * @atomic_flush: mark the end of a window update
  * @update_plane: apply hardware specific overlay data to registers.
@@ -108,6 +109,8 @@ struct exynos_drm_crtc_ops {
 	int (*enable_vblank)(struct exynos_drm_crtc *crtc);
 	void (*disable_vblank)(struct exynos_drm_crtc *crtc);
 	void (*wait_for_vblank)(struct exynos_drm_crtc *crtc);
+	int (*atomic_check)(struct exynos_drm_crtc *crtc,
+			    struct drm_crtc_state *state);
 	void (*atomic_begin)(struct exynos_drm_crtc *crtc,
 			      struct exynos_drm_plane *plane);
 	void (*update_plane)(struct exynos_drm_crtc *crtc,