drm: rcar-du: Replace dev_private with container_of

Now that drm_device is embedded in rcar_du_device, we can use
container_of to get the rcar_du_device pointer from the drm_device,
instead of using the drm_device.dev_private field.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>

drivers/gpu/drm/rcar-du/rcar_du_drv.c

@@ -585,8 +585,6 @@ static int rcar_du_probe(struct platform_device *pdev)
 		return PTR_ERR(rcdu->mmio);
 
 	/* DRM/KMS objects */
-	rcdu->ddev.dev_private = rcdu;
-
 	ret = rcar_du_modeset_init(rcdu);
 	if (ret < 0) {
 		if (ret != -EPROBE_DEFER)

drivers/gpu/drm/rcar-du/rcar_du_drv.h

@@ -99,6 +99,11 @@ struct rcar_du_device {
 	unsigned int vspd1_sink;
 };
 
+static inline struct rcar_du_device *to_rcar_du_device(struct drm_device *dev)
+{
+	return container_of(dev, struct rcar_du_device, ddev);
+}
+
 static inline bool rcar_du_has(struct rcar_du_device *rcdu,
 			       unsigned int feature)
 {

drivers/gpu/drm/rcar-du/rcar_du_kms.c

@@ -327,7 +327,7 @@ const struct rcar_du_format_info *rcar_du_format_info(u32 fourcc)
 int rcar_du_dumb_create(struct drm_file *file, struct drm_device *dev,
 			struct drm_mode_create_dumb *args)
 {
-	struct rcar_du_device *rcdu = dev->dev_private;
+	struct rcar_du_device *rcdu = to_rcar_du_device(dev);
 	unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
 	unsigned int align;
 
@@ -349,7 +349,7 @@ static struct drm_framebuffer *
 rcar_du_fb_create(struct drm_device *dev, struct drm_file *file_priv,
 		  const struct drm_mode_fb_cmd2 *mode_cmd)
 {
-	struct rcar_du_device *rcdu = dev->dev_private;
+	struct rcar_du_device *rcdu = to_rcar_du_device(dev);
 	const struct rcar_du_format_info *format;
 	unsigned int chroma_pitch;
 	unsigned int max_pitch;
@@ -421,7 +421,7 @@ rcar_du_fb_create(struct drm_device *dev, struct drm_file *file_priv,
 static int rcar_du_atomic_check(struct drm_device *dev,
 				struct drm_atomic_state *state)
 {
-	struct rcar_du_device *rcdu = dev->dev_private;
+	struct rcar_du_device *rcdu = to_rcar_du_device(dev);
 	int ret;
 
 	ret = drm_atomic_helper_check(dev, state);
@@ -437,7 +437,7 @@ static int rcar_du_atomic_check(struct drm_device *dev,
 static void rcar_du_atomic_commit_tail(struct drm_atomic_state *old_state)
 {
 	struct drm_device *dev = old_state->dev;
-	struct rcar_du_device *rcdu = dev->dev_private;
+	struct rcar_du_device *rcdu = to_rcar_du_device(dev);
 	struct drm_crtc_state *crtc_state;
 	struct drm_crtc *crtc;
 	unsigned int i;

drivers/gpu/drm/rcar-du/rcar_du_plane.c

@@ -128,7 +128,7 @@ static int rcar_du_plane_hwalloc(struct rcar_du_plane *plane,
 int rcar_du_atomic_check_planes(struct drm_device *dev,
 				struct drm_atomic_state *state)
 {
-	struct rcar_du_device *rcdu = dev->dev_private;
+	struct rcar_du_device *rcdu = to_rcar_du_device(dev);
 	unsigned int group_freed_planes[RCAR_DU_MAX_GROUPS] = { 0, };
 	unsigned int group_free_planes[RCAR_DU_MAX_GROUPS] = { 0, };
 	bool needs_realloc = false;