ARM: imx: register reset controller from a platform driver

Starting with commit 6b2117a ("of: property: fw_devlink: Add
support for "resets" and "pwms""), the imx-drm driver fails to load
due to forever dormant devlinks to the reset-controller node. This
node was never associated with a struct device.

Add a platform device to allow fw_devnode to activate the devlinks.

Fixes: 6b2117a ("of: property: fw_devlink: Add support for "resets" and "pwms"")
Signed-off-by: Philipp Zabel <[email protected]>
Tested-by: Fabio Estevam <[email protected]>
Reviewed-by: Saravana Kannan <[email protected]>
Signed-off-by: Shawn Guo <[email protected]>

Author: pH5

arch/arm/mach-imx/src.c

@@ -9,6 +9,7 @@
 #include <linux/iopoll.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
+#include <linux/platform_device.h>
 #include <linux/reset-controller.h>
 #include <linux/smp.h>
 #include <asm/smp_plat.h>
@@ -81,11 +82,6 @@ static const struct reset_control_ops imx_src_ops = {
 	.reset = imx_src_reset_module,
 };
 
-static struct reset_controller_dev imx_reset_controller = {
-	.ops = &imx_src_ops,
-	.nr_resets = ARRAY_SIZE(sw_reset_bits),
-};
-
 static void imx_gpcv2_set_m_core_pgc(bool enable, u32 offset)
 {
 	writel_relaxed(enable, gpc_base + offset);
@@ -177,10 +173,6 @@ void __init imx_src_init(void)
 	src_base = of_iomap(np, 0);
 	WARN_ON(!src_base);
 
-	imx_reset_controller.of_node = np;
-	if (IS_ENABLED(CONFIG_RESET_CONTROLLER))
-		reset_controller_register(&imx_reset_controller);
-
 	/*
 	 * force warm reset sources to generate cold reset
 	 * for a more reliable restart
@@ -214,3 +206,33 @@ void __init imx7_src_init(void)
 	if (!gpc_base)
 		return;
 }
+
+static const struct of_device_id imx_src_dt_ids[] = {
+	{ .compatible = "fsl,imx51-src" },
+	{ /* sentinel */ }
+};
+
+static int imx_src_probe(struct platform_device *pdev)
+{
+	struct reset_controller_dev *rcdev;
+
+	rcdev = devm_kzalloc(&pdev->dev, sizeof(*rcdev), GFP_KERNEL);
+	if (!rcdev)
+		return -ENOMEM;
+
+	rcdev->ops = &imx_src_ops;
+	rcdev->dev = &pdev->dev;
+	rcdev->of_node = pdev->dev.of_node;
+	rcdev->nr_resets = ARRAY_SIZE(sw_reset_bits);
+
+	return devm_reset_controller_register(&pdev->dev, rcdev);
+}
+
+static struct platform_driver imx_src_driver = {
+	.driver = {
+		.name = "imx-src",
+		.of_match_table = imx_src_dt_ids,
+	},
+	.probe = imx_src_probe,
+};
+builtin_platform_driver(imx_src_driver);