drm/exynos: add mode_fixup callback to exynos_drm_crtc_ops

crtc::mode_fixup callback is required by crtcs which internally use
a different mode than requested by user - case of Exynos Mixer.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_crtc.c

@@ -95,8 +95,23 @@ static enum drm_mode_status exynos_crtc_mode_valid(struct drm_crtc *crtc,
 	return MODE_OK;
 }
 
+static bool exynos_crtc_mode_fixup(struct drm_crtc *crtc,
+		const struct drm_display_mode *mode,
+		struct drm_display_mode *adjusted_mode)
+{
+	struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(crtc);
+
+	if (exynos_crtc->ops->mode_fixup)
+		return exynos_crtc->ops->mode_fixup(exynos_crtc, mode,
+				adjusted_mode);
+
+	return true;
+}
+
+
 static const struct drm_crtc_helper_funcs exynos_crtc_helper_funcs = {
 	.mode_valid	= exynos_crtc_mode_valid,
+	.mode_fixup	= exynos_crtc_mode_fixup,
 	.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

@@ -136,6 +136,9 @@ struct exynos_drm_crtc_ops {
 	u32 (*get_vblank_counter)(struct exynos_drm_crtc *crtc);
 	enum drm_mode_status (*mode_valid)(struct exynos_drm_crtc *crtc,
 		const struct drm_display_mode *mode);
+	bool (*mode_fixup)(struct exynos_drm_crtc *crtc,
+			   const struct drm_display_mode *mode,
+			   struct drm_display_mode *adjusted_mode);
 	int (*atomic_check)(struct exynos_drm_crtc *crtc,
 			    struct drm_crtc_state *state);
 	void (*atomic_begin)(struct exynos_drm_crtc *crtc);