Commit 09fb07bc authored by Feng Kan's avatar Feng Kan Committed by Sebastian Reichel
Browse files

power: reset: Add generic SYSCON register mapped reset 



Add a generic SYSCON register mapped reset mechanism.

Signed-off-by: default avatarFeng Kan <fkan@apm.com>
Signed-off-by: default avatarSebastian Reichel <sre@kernel.org>
parent a3c0c3e7

drivers/power/reset/Kconfig

+5 −0
Original line number Diff line number Diff line
@@ -118,3 +118,8 @@ config POWER_RESET_KEYSTONE 
	help

	  Reboot support for the KEYSTONE SoCs.



config POWER_RESET_SYSCON

	bool "Generic SYSCON regmap reset driver"

	depends on POWER_RESET && MFD_SYSCON && OF

	help

	  Reboot support for generic SYSCON mapped register reset.

drivers/power/reset/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -13,3 +13,4 @@ obj-$(CONFIG_POWER_RESET_ST) += st-poweroff.o 
obj-$(CONFIG_POWER_RESET_VEXPRESS) += vexpress-poweroff.o

obj-$(CONFIG_POWER_RESET_XGENE) += xgene-reboot.o

obj-$(CONFIG_POWER_RESET_KEYSTONE) += keystone-reset.o

obj-$(CONFIG_POWER_RESET_SYSCON) += syscon-reboot.o

drivers/power/reset/syscon-reboot.c

0 → 100644
+96 −0
Original line number Diff line number Diff line 
/*

 * Generic Syscon Reboot Driver

 *

 * Copyright (c) 2013, Applied Micro Circuits Corporation

 * Author: Feng Kan <fkan@apm.com>

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License as

 * published by the Free Software Foundation; either version 2 of

 * the License, or (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */

#include <linux/io.h>

#include <linux/of_device.h>

#include <linux/of_address.h>

#include <linux/platform_device.h>

#include <linux/notifier.h>

#include <linux/mfd/syscon.h>

#include <linux/regmap.h>

#include <linux/reboot.h>



struct syscon_reboot_context {

	struct regmap *map;

	u32 offset;

	u32 mask;

	struct notifier_block restart_handler;

};



static struct syscon_reboot_context *syscon_reboot_ctx;



static int syscon_restart_handle(struct notifier_block *this,

					unsigned long mode, void *cmd)

{

	struct syscon_reboot_context *ctx = syscon_reboot_ctx;

	unsigned long timeout;



	/* Issue the reboot */

	if (ctx->map)

		regmap_write(ctx->map, ctx->offset, ctx->mask);



	timeout = jiffies + HZ;

	while (time_before(jiffies, timeout))

		cpu_relax();



	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 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))

		return PTR_ERR(ctx->map);



	if (of_property_read_u32(pdev->dev.of_node, "offset", &ctx->offset))

		return -EINVAL;



	if (of_property_read_u32(pdev->dev.of_node, "mask", &ctx->mask))

		return -EINVAL;



	ctx->restart_handler.notifier_call = syscon_restart_handle;

	ctx->restart_handler.priority = 128;

	err = register_restart_handler(&ctx->restart_handler);

	if (err)

		dev_err(dev, "can't register restart notifier (err=%d)\n", err);



	syscon_reboot_ctx = ctx;



	return 0;

}



static 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,

	},

};

module_platform_driver(syscon_reboot_driver);