drm: rcar-du: Drop LVDS device tree backward compatibility

The rcar-du driver goes to great lengths to preserve device tree
backward compatibility for the LVDS encoders by patching old device
trees at runtime.

The last R-Car Gen2 platform was converted to the new bindings commit
edb0c3a ("ARM: dts: r8a7793: Convert to new LVDS DT bindings"),
in v4.17, and the last RZ/G1 platform converted in commit
6a6a797 ("ARM: dts: r8a7743: Convert to new LVDS DT bindings"),
in v5.0. Both are older than commit 5825614 ("clk: renesas:
Remove R-Car Gen2 legacy DT clock support"), in v5.5, which removes
support for legacy bindings for clocks. The LVDS compatibility code is
thus not needed anymore. Drop it.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>

drivers/gpu/drm/rcar-du/Makefile

@@ -6,12 +6,6 @@ rcar-du-drm-y := rcar_du_crtc.o \
 		 rcar_du_kms.o \
 		 rcar_du_plane.o \
 
-rcar-du-drm-$(CONFIG_DRM_RCAR_LVDS)	+= rcar_du_of.o \
-					   rcar_du_of_lvds_r8a7790.dtb.o \
-					   rcar_du_of_lvds_r8a7791.dtb.o \
-					   rcar_du_of_lvds_r8a7793.dtb.o \
-					   rcar_du_of_lvds_r8a7795.dtb.o \
-					   rcar_du_of_lvds_r8a7796.dtb.o
 rcar-du-drm-$(CONFIG_DRM_RCAR_VSP)	+= rcar_du_vsp.o
 rcar-du-drm-$(CONFIG_DRM_RCAR_WRITEBACK) += rcar_du_writeback.o
 

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

@@ -28,7 +28,6 @@
 
 #include "rcar_du_drv.h"
 #include "rcar_du_kms.h"
-#include "rcar_du_of.h"
 #include "rcar_du_regs.h"
 
 /* -----------------------------------------------------------------------------
@@ -634,6 +633,9 @@ static int rcar_du_probe(struct platform_device *pdev)
 	unsigned int mask;
 	int ret;
 
+	if (drm_firmware_drivers_only())
+		return -ENODEV;
+
 	/* Allocate and initialize the R-Car device structure. */
 	rcdu = devm_drm_dev_alloc(&pdev->dev, &rcar_du_driver,
 				  struct rcar_du_device, ddev);
@@ -699,22 +701,7 @@ static struct platform_driver rcar_du_platform_driver = {
 	},
 };
 
-static int __init rcar_du_init(void)
-{
-	if (drm_firmware_drivers_only())
-		return -ENODEV;
-
-	rcar_du_of_init(rcar_du_of_table);
-
-	return platform_driver_register(&rcar_du_platform_driver);
-}
-module_init(rcar_du_init);
-
-static void __exit rcar_du_exit(void)
-{
-	platform_driver_unregister(&rcar_du_platform_driver);
-}
-module_exit(rcar_du_exit);
+module_platform_driver(rcar_du_platform_driver);
 
 MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
 MODULE_DESCRIPTION("Renesas R-Car Display Unit DRM Driver");