drm/sun4i: backend: Create regmap after access is possible

The backend has various clocks and reset controls that need to be
enabled and deasserted before register access is possible.

Move the creation of the regmap to after the clocks and reset controls
have been configured where it makes more sense.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171014040252.9621-3-wens@csie.org

drivers/gpu/drm/sun4i/sun4i_backend.c

@@ -369,13 +369,6 @@ static int sun4i_backend_bind(struct device *dev, struct device *master,
 	if (IS_ERR(regs))
 		return PTR_ERR(regs);
 
-	backend->engine.regs = devm_regmap_init_mmio(dev, regs,
-						     &sun4i_backend_regmap_config);
-	if (IS_ERR(backend->engine.regs)) {
-		dev_err(dev, "Couldn't create the backend regmap\n");
-		return PTR_ERR(backend->engine.regs);
-	}
-
 	backend->reset = devm_reset_control_get(dev, NULL);
 	if (IS_ERR(backend->reset)) {
 		dev_err(dev, "Couldn't get our reset line\n");
@@ -421,6 +414,13 @@ static int sun4i_backend_bind(struct device *dev, struct device *master,
 		}
 	}
 
+	backend->engine.regs = devm_regmap_init_mmio(dev, regs,
+						     &sun4i_backend_regmap_config);
+	if (IS_ERR(backend->engine.regs)) {
+		dev_err(dev, "Couldn't create the backend regmap\n");
+		return PTR_ERR(backend->engine.regs);
+	}
+
 	list_add_tail(&backend->engine.list, &drv->engine_list);
 
 	/* Reset the registers */