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>

1 files changed, 28 insertions, 11 deletions

diff --git a/drivers/clk/meson/gxbb.c b/drivers/clk/meson/gxbb.c
index 5ab8338eb894..bb0b0529ca81 100644
--- a/drivers/clk/meson/gxbb.c
+++ b/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;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!res)
-		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");
 
-	clk_base = devm_ioremap(dev, res->start, resource_size(res));
-	if (!clk_base) {
-		pr_err("%s: Unable to map clk base\n", __func__);
-		return -ENXIO;
-	}
+		/*
+		 * 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);
-	if (IS_ERR(map))
-		return PTR_ERR(map);
+		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++)