drm/ingenic: prepare ingenic drm for later addition of JZ4780

This changes the way the regmap is allocated to prepare for the
later addition of the JZ4780 which has more registers and bits
than the others.

Therefore we make the regmap as big as the reg property in
the device tree tells.
Suggested-by: NPaul Cercueil <paul@crapouillou.net>
Signed-off-by: NH. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: NPaul Cercueil <paul@crapouillou.net>
Link: https://patchwork.freedesktop.org/patch/msgid/ee65e70e91268b3963f8a6581c8aa6c3b643c53e.1638470392.git.hns@goldelico.com

drivers/gpu/drm/ingenic/ingenic-drm-drv.c

@@ -173,7 +173,6 @@ static const struct regmap_config ingenic_drm_regmap_config = {
 	.val_bits = 32,
 	.reg_stride = 4,
 
-	.max_register = JZ_REG_LCD_SIZE1,
 	.writeable_reg = ingenic_drm_writeable_reg,
 };
 
@@ -1011,6 +1010,8 @@ static int ingenic_drm_bind(struct device *dev, bool has_components)
 	struct ingenic_drm_bridge *ib;
 	struct drm_device *drm;
 	void __iomem *base;
+	struct resource *res;
+	struct regmap_config regmap_config;
 	long parent_rate;
 	unsigned int i, clone_mask = 0;
 	int ret, irq;
@@ -1056,14 +1057,16 @@ static int ingenic_drm_bind(struct device *dev, bool has_components)
 	drm->mode_config.funcs = &ingenic_drm_mode_config_funcs;
 	drm->mode_config.helper_private = &ingenic_drm_mode_config_helpers;
 
-	base = devm_platform_ioremap_resource(pdev, 0);
+	base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
 	if (IS_ERR(base)) {
 		dev_err(dev, "Failed to get memory resource\n");
 		return PTR_ERR(base);
 	}
 
+	regmap_config = ingenic_drm_regmap_config;
+	regmap_config.max_register = res->end - res->start;
 	priv->map = devm_regmap_init_mmio(dev, base,
-					  &ingenic_drm_regmap_config);
+					  &regmap_config);
 	if (IS_ERR(priv->map)) {
 		dev_err(dev, "Failed to create regmap\n");
 		return PTR_ERR(priv->map);