clk: meson: use hhi syscon if available

On gxbb and axg, try to get the hhi regmap from the parent DT node, which
should be the HHI system controller once the necessary changes have been
made in amlogic's DTs

Until then, if getting regmap through the system controller fails, the
clock controller will fall back to the old way, requesting memory region
directly and then registering the regmap itself.

This should allow a smooth transition to syscon
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

drivers/clk/meson/Kconfig

@@ -22,6 +22,7 @@ config COMMON_CLK_GXBB
 	depends on COMMON_CLK_AMLOGIC
 	select RESET_CONTROLLER
 	select COMMON_CLK_REGMAP_MESON
+	select MFD_SYSCON
 	help
 	  Support for the clock controller on AmLogic S905 devices, aka gxbb.
 	  Say Y if you want peripherals and CPU frequency scaling to work.
@@ -31,6 +32,7 @@ config COMMON_CLK_AXG
 	depends on COMMON_CLK_AMLOGIC
 	select RESET_CONTROLLER
 	select COMMON_CLK_REGMAP_MESON
+	select MFD_SYSCON
 	help
 	  Support for the clock controller on AmLogic A113D devices, aka axg.
 	  Say Y if you want peripherals and CPU frequency scaling to work.

drivers/clk/meson/axg.c

@@ -14,6 +14,7 @@
 #include <linux/init.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
+#include <linux/mfd/syscon.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 
@@ -850,24 +851,40 @@ static int axg_clkc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct resource *res;
-	void __iomem *clk_base;
+	void __iomem *clk_base = NULL;
 	struct regmap *map;
 	int ret, i;
 
-	/*  Generic clocks and PLLs */
+	/* Get the hhi system controller node if available */
+	map = syscon_node_to_regmap(of_get_parent(dev->of_node));
+	if (IS_ERR(map)) {
+		dev_err(dev,
+			"failed to get HHI regmap - Trying obsolete regs\n");
+
+		/*
+		 * FIXME: HHI registers should be accessed through
+		 * the appropriate system controller. This is required because
+		 * there is more than just clocks in this register space
+		 *
+		 * This fallback method is only provided temporarily until
+		 * all the platform DTs are properly using the syscon node
+		 */
 		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 		if (!res)
 			return -EINVAL;
 
+
 		clk_base = devm_ioremap(dev, res->start, resource_size(res));
 		if (!clk_base) {
 			dev_err(dev, "Unable to map clk base\n");
 			return -ENXIO;
 		}
 
-	map = devm_regmap_init_mmio(dev, clk_base, &clkc_regmap_config);
+		map = devm_regmap_init_mmio(dev, clk_base,
+					    &clkc_regmap_config);
 		if (IS_ERR(map))
 			return PTR_ERR(map);
+	}
 
 	/* Populate regmap for the regmap backed clocks */
 	for (i = 0; i < ARRAY_SIZE(axg_clk_regmaps); i++)

drivers/clk/meson/gxbb.c

@@ -22,6 +22,7 @@
 #include <linux/init.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
+#include <linux/mfd/syscon.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 
@@ -2045,19 +2046,35 @@ static int gxbb_clkc_probe(struct platform_device *pdev)
 	if (!clkc_data)
 		return -EINVAL;
 
+	/* Get the hhi system controller node if available */
+	map = syscon_node_to_regmap(of_get_parent(dev->of_node));
+	if (IS_ERR(map)) {
+		dev_err(dev,
+			"failed to get HHI regmap - Trying obsolete regs\n");
+
+		/*
+		 * FIXME: HHI registers should be accessed through
+		 * the appropriate system controller. This is required because
+		 * there is more than just clocks in this register space
+		 *
+		 * This fallback method is only provided temporarily until
+		 * all the platform DTs are properly using the syscon node
+		 */
 		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 		if (!res)
 			return -EINVAL;
 
 		clk_base = devm_ioremap(dev, res->start, resource_size(res));
 		if (!clk_base) {
-		pr_err("%s: Unable to map clk base\n", __func__);
+			dev_err(dev, "Unable to map clk base\n");
 			return -ENXIO;
 		}
 
-	map = devm_regmap_init_mmio(dev, clk_base, &clkc_regmap_config);
+		map = devm_regmap_init_mmio(dev, clk_base,
+					    &clkc_regmap_config);
 		if (IS_ERR(map))
 			return PTR_ERR(map);
+	}
 
 	/* Populate regmap for the common regmap backed clocks */
 	for (i = 0; i < ARRAY_SIZE(gx_clk_regmaps); i++)