clk: sprd: set max_register according to mapping range

In sprd clock driver, regmap_config.max_register was set to a fixed value
which is likely larger than the address range configured in device tree,
when reading registers through debugfs it would cause access violation.

Fixes: d41f59f ("clk: sprd: Add common infrastructure")
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Link: https://lore.kernel.org/r/20230316023624.758204-1-chunyan.zhang@unisoc.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/sprd/common.c

@@ -17,7 +17,6 @@ static const struct regmap_config sprdclk_regmap_config = {
 	.reg_bits	= 32,
 	.reg_stride	= 4,
 	.val_bits	= 32,
-	.max_register	= 0xffff,
 	.fast_io	= true,
 };
 
@@ -43,6 +42,8 @@ int sprd_clk_regmap_init(struct platform_device *pdev,
 	struct device *dev = &pdev->dev;
 	struct device_node *node = dev->of_node, *np;
 	struct regmap *regmap;
+	struct resource *res;
+	struct regmap_config reg_config = sprdclk_regmap_config;
 
 	if (of_find_property(node, "sprd,syscon", NULL)) {
 		regmap = syscon_regmap_lookup_by_phandle(node, "sprd,syscon");
@@ -59,12 +60,14 @@ int sprd_clk_regmap_init(struct platform_device *pdev,
 			return PTR_ERR(regmap);
 		}
 	} else {
-		base = devm_platform_ioremap_resource(pdev, 0);
+		base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
 		if (IS_ERR(base))
 			return PTR_ERR(base);
 
+		reg_config.max_register = resource_size(res) - reg_config.reg_stride;
+
 		regmap = devm_regmap_init_mmio(&pdev->dev, base,
-					       &sprdclk_regmap_config);
+					       &reg_config);
 		if (IS_ERR(regmap)) {
 			pr_err("failed to init regmap\n");
 			return PTR_ERR(regmap);