drm/arc: Stop using drm_device->dev_private

Upcasting using a container_of macro is more typesafe, faster and
easier for the compiler to optimize.

Cc: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210112084358.2771527-2-daniel.vetter@ffwll.ch

drivers/gpu/drm/arc/arcpgu.h

@@ -17,6 +17,8 @@ struct arcpgu_drm_private {
 	struct drm_plane	*plane;
 };
 
+#define dev_to_arcpgu(x) container_of(x, struct arcpgu_drm_private, drm)
+
 #define crtc_to_arcpgu_priv(x) container_of(x, struct arcpgu_drm_private, crtc)
 
 static inline void arc_pgu_write(struct arcpgu_drm_private *arcpgu,

drivers/gpu/drm/arc/arcpgu_crtc.c

@@ -176,7 +176,7 @@ static const struct drm_plane_funcs arc_pgu_plane_funcs = {
 
 static struct drm_plane *arc_pgu_plane_init(struct drm_device *drm)
 {
-	struct arcpgu_drm_private *arcpgu = drm->dev_private;
+	struct arcpgu_drm_private *arcpgu = dev_to_arcpgu(drm);
 	struct drm_plane *plane = NULL;
 	int ret;
 
@@ -200,7 +200,7 @@ static struct drm_plane *arc_pgu_plane_init(struct drm_device *drm)
 
 int arc_pgu_setup_crtc(struct drm_device *drm)
 {
-	struct arcpgu_drm_private *arcpgu = drm->dev_private;
+	struct arcpgu_drm_private *arcpgu = dev_to_arcpgu(drm);
 	struct drm_plane *primary;
 	int ret;
 

drivers/gpu/drm/arc/arcpgu_drv.c

@@ -50,8 +50,6 @@ static int arcpgu_load(struct arcpgu_drm_private *arcpgu)
 	struct resource *res;
 	int ret;
 
-	drm->dev_private = arcpgu;
-
 	arcpgu->clk = devm_clk_get(drm->dev, "pxlclk");
 	if (IS_ERR(arcpgu->clk))
 		return PTR_ERR(arcpgu->clk);
@@ -120,7 +118,7 @@ static int arcpgu_show_pxlclock(struct seq_file *m, void *arg)
 {
 	struct drm_info_node *node = (struct drm_info_node *)m->private;
 	struct drm_device *drm = node->minor->dev;
-	struct arcpgu_drm_private *arcpgu = drm->dev_private;
+	struct arcpgu_drm_private *arcpgu = dev_to_arcpgu(drm);
 	unsigned long clkrate = clk_get_rate(arcpgu->clk);
 	unsigned long mode_clock = arcpgu->crtc.mode.crtc_clock * 1000;