1 files changed, 103 insertions, 0 deletions
diff --git a/drivers/power/reset/syscon-reboot.c b/drivers/power/reset/syscon-reboot.c
new file mode 100644
index 0000000000..4d622c19bc
--- /dev/null
+++ b/drivers/power/reset/syscon-reboot.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Generic Syscon Reboot Driver
+ *
+ * Copyright (c) 2013, Applied Micro Circuits Corporation
+ * Author: Feng Kan <fkan@apm.com>
+ */
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/notifier.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/regmap.h>
+
+struct syscon_reboot_context {
+	struct regmap *map;
+	u32 offset;
+	u32 value;
+	u32 mask;
+	struct notifier_block restart_handler;
+};
+
+static int syscon_restart_handle(struct notifier_block *this,
+					unsigned long mode, void *cmd)
+{
+	struct syscon_reboot_context *ctx =
+			container_of(this, struct syscon_reboot_context,
+					restart_handler);
+
+	/* Issue the reboot */
+	regmap_update_bits(ctx->map, ctx->offset, ctx->mask, ctx->value);
+
+	mdelay(1000);
+
+	pr_emerg("Unable to restart system\n");
+	return NOTIFY_DONE;
+}
+
+static int syscon_reboot_probe(struct platform_device *pdev)
+{
+	struct syscon_reboot_context *ctx;
+	struct device *dev = &pdev->dev;
+	int mask_err, value_err;
+	int priority;
+	int err;
+
+	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->map = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap");
+	if (IS_ERR(ctx->map)) {
+		ctx->map = syscon_node_to_regmap(dev->parent->of_node);
+		if (IS_ERR(ctx->map))
+			return PTR_ERR(ctx->map);
+	}
+
+	if (of_property_read_s32(pdev->dev.of_node, "priority", &priority))
+		priority = 192;
+
+	if (of_property_read_u32(pdev->dev.of_node, "offset", &ctx->offset))
+		return -EINVAL;
+
+	value_err = of_property_read_u32(pdev->dev.of_node, "value", &ctx->value);
+	mask_err = of_property_read_u32(pdev->dev.of_node, "mask", &ctx->mask);
+	if (value_err && mask_err) {
+		dev_err(dev, "unable to read 'value' and 'mask'");
+		return -EINVAL;
+	}
+
+	if (value_err) {
+		/* support old binding */
+		ctx->value = ctx->mask;
+		ctx->mask = 0xFFFFFFFF;
+	} else if (mask_err) {
+		/* support value without mask*/
+		ctx->mask = 0xFFFFFFFF;
+	}
+
+	ctx->restart_handler.notifier_call = syscon_restart_handle;
+	ctx->restart_handler.priority = priority;
+	err = register_restart_handler(&ctx->restart_handler);
+	if (err)
+		dev_err(dev, "can't register restart notifier (err=%d)\n", err);
+
+	return err;
+}
+
+static const struct of_device_id syscon_reboot_of_match[] = {
+	{ .compatible = "syscon-reboot" },
+	{}
+};
+
+static struct platform_driver syscon_reboot_driver = {
+	.probe = syscon_reboot_probe,
+	.driver = {
+		.name = "syscon-reboot",
+		.of_match_table = syscon_reboot_of_match,
+	},
+};
+builtin_platform_driver(syscon_reboot_driver);