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path: root/drivers/power/reset/syscon-reboot.c
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Diffstat (limited to 'drivers/power/reset/syscon-reboot.c')
-rw-r--r--drivers/power/reset/syscon-reboot.c103
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);