drm: exynos: use crtc helper drm_crtc_from_index()

Use drm_crtc_from_index() to find drm_crtc for given index, so that we
do not need to maintain a pointer array in struct exynos_drm_private.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Cc: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1483961145-18453-2-git-send-email-shawnguo@kernel.org

drivers/gpu/drm/exynos/exynos_drm_crtc.c

@@ -109,9 +109,6 @@ static const struct drm_crtc_helper_funcs exynos_crtc_helper_funcs = {
 static void exynos_drm_crtc_destroy(struct drm_crtc *crtc)
 {
 	struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(crtc);
-	struct exynos_drm_private *private = crtc->dev->dev_private;
-
-	private->crtc[exynos_crtc->pipe] = NULL;
 
 	drm_crtc_cleanup(crtc);
 	kfree(exynos_crtc);
@@ -134,7 +131,6 @@ struct exynos_drm_crtc *exynos_drm_crtc_create(struct drm_device *drm_dev,
 					void *ctx)
 {
 	struct exynos_drm_crtc *exynos_crtc;
-	struct exynos_drm_private *private = drm_dev->dev_private;
 	struct drm_crtc *crtc;
 	int ret;
 
@@ -149,8 +145,6 @@ struct exynos_drm_crtc *exynos_drm_crtc_create(struct drm_device *drm_dev,
 
 	crtc = &exynos_crtc->base;
 
-	private->crtc[pipe] = crtc;
-
 	ret = drm_crtc_init_with_planes(drm_dev, crtc, plane, NULL,
 					&exynos_crtc_funcs, NULL);
 	if (ret < 0)

drivers/gpu/drm/exynos/exynos_drm_drv.h

@@ -211,12 +211,6 @@ struct drm_exynos_file_private {
 struct exynos_drm_private {
 	struct drm_fb_helper *fb_helper;
 
-	/*
-	 * created crtc object would be contained at this array and
-	 * this array is used to be aware of which crtc did it request vblank.
-	 */
-	struct drm_crtc *crtc[MAX_CRTC];
-
 	struct device *dma_dev;
 	void *mapping;
 
@@ -231,9 +225,9 @@ struct exynos_drm_private {
 static inline struct exynos_drm_crtc *
 exynos_drm_crtc_from_pipe(struct drm_device *dev, int pipe)
 {
-	struct exynos_drm_private *private = dev->dev_private;
+	struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
 
-	return to_exynos_crtc(private->crtc[pipe]);
+	return to_exynos_crtc(crtc);
 }
 
 static inline struct device *to_dma_dev(struct drm_device *dev)