clk: sunxi: Make the mod0 clk driver also a platform driver

With the prcm in sun6i (and some later SoCs) some mod0 clocks are instantiated
through the mfd framework, and as such do not work with of_clk_declare, since
they do not have registers assigned to them yet at of_clk_declare init time.

Silence the error on not finding registers in the of_clk_declare mod0 clk
setup method, and also register mod0-clk support as a platform driver to work
properly with mfd instantiated mod0 clocks.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

drivers/clk/sunxi/clk-mod0.c

@@ -17,6 +17,7 @@
 #include <linux/clk-provider.h>
 #include <linux/clkdev.h>
 #include <linux/of_address.h>
+#include <linux/platform_device.h>
 
 #include "clk-factors.h"
 
@@ -67,7 +68,7 @@ static struct clk_factors_config sun4i_a10_mod0_config = {
 	.pwidth = 2,
 };
 
-static const struct factors_data sun4i_a10_mod0_data __initconst = {
+static const struct factors_data sun4i_a10_mod0_data = {
 	.enable = 31,
 	.mux = 24,
 	.muxmask = BIT(1) | BIT(0),
@@ -83,8 +84,11 @@ static void __init sun4i_a10_mod0_setup(struct device_node *node)
 
 	reg = of_iomap(node, 0);
 	if (!reg) {
-		pr_err("Could not get registers for mod0-clk: %s\n",
-		       node->name);
+		/*
+		 * This happens with mod0 clk nodes instantiated through
+		 * mfd, as those do not have their resources assigned at
+		 * CLK_OF_DECLARE time yet, so do not print an error.
+		 */
 		return;
 	}
 
@@ -93,6 +97,39 @@ static void __init sun4i_a10_mod0_setup(struct device_node *node)
 }
 CLK_OF_DECLARE(sun4i_a10_mod0, "allwinner,sun4i-a10-mod0-clk", sun4i_a10_mod0_setup);
 
+static int sun4i_a10_mod0_clk_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct resource *r;
+	void __iomem *reg;
+
+	if (!np)
+		return -ENODEV;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	reg = devm_ioremap_resource(&pdev->dev, r);
+	if (IS_ERR(reg))
+		return PTR_ERR(reg);
+
+	sunxi_factors_register(np, &sun4i_a10_mod0_data,
+			       &sun4i_a10_mod0_lock, reg);
+	return 0;
+}
+
+static const struct of_device_id sun4i_a10_mod0_clk_dt_ids[] = {
+	{ .compatible = "allwinner,sun4i-a10-mod0-clk" },
+	{ /* sentinel */ }
+};
+
+static struct platform_driver sun4i_a10_mod0_clk_driver = {
+	.driver = {
+		.name = "sun4i-a10-mod0-clk",
+		.of_match_table = sun4i_a10_mod0_clk_dt_ids,
+	},
+	.probe = sun4i_a10_mod0_clk_probe,
+};
+module_platform_driver(sun4i_a10_mod0_clk_driver);
+
 static DEFINE_SPINLOCK(sun5i_a13_mbus_lock);
 
 static void __init sun5i_a13_mbus_setup(struct device_node *node)