power: reset: Add Axxia system reset driver

Axxia Restart Driver

This driver can do reset of the Axxia SoC. It uses the registers in the syscon

block to initiate a chip reset.

Required Properties:

  -compatible: "lsi,axm55xx-reset"

  -syscon: phandle to the syscon node.

Example:

	syscon: syscon@2010030000 {

		compatible = "lsi,axxia-syscon", "syscon";

		reg = <0x20 0x10030000 0 0x2000>;

	};

	reset: reset@2010031000 {

		compatible = "lsi,axm55xx-reset";

		syscon = <&syscon>;

	};

	help

	  This driver supports turning off board via a ams AS3722 power-off.

config POWER_RESET_AXXIA

	bool "LSI Axxia reset driver"

	depends on POWER_RESET && ARCH_AXXIA

	help

	  This driver supports restart for Axxia SoC.

	  Say Y if you have an Axxia family SoC.

config POWER_RESET_GPIO

	bool "GPIO power-off driver"

	depends on OF_GPIO && POWER_RESET

obj-$(CONFIG_POWER_RESET_AS3722) += as3722-poweroff.o

obj-$(CONFIG_POWER_RESET_AXXIA) += axxia-reset.o

obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o

obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o

obj-$(CONFIG_POWER_RESET_QNAP) += qnap-poweroff.o

/*

 * Reset driver for Axxia devices

 *

 * Copyright (C) 2014 LSI

 *

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

 * it under the terms of the GNU General Public License version 2 and

 * only version 2 as published by the Free Software Foundation.

 *

 * 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/init.h>

#include <linux/err.h>

#include <linux/io.h>

#include <linux/kernel.h>

#include <linux/mfd/syscon.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/reboot.h>

#include <linux/regmap.h>

#include <asm/system_misc.h>

#define SC_CRIT_WRITE_KEY	0x1000

#define SC_LATCH_ON_RESET	0x1004

#define SC_RESET_CONTROL	0x1008

#define   RSTCTL_RST_ZERO	(1<<3)

#define   RSTCTL_RST_FAB	(1<<2)

#define   RSTCTL_RST_CHIP	(1<<1)

#define   RSTCTL_RST_SYS	(1<<0)

#define SC_EFUSE_INT_STATUS	0x180c

#define   EFUSE_READ_DONE	(1<<31)

static struct regmap *syscon;

static void do_axxia_restart(enum reboot_mode reboot_mode, const char *cmd)

{

	/* Access Key (0xab) */

	regmap_write(syscon, SC_CRIT_WRITE_KEY, 0xab);

	/* Select internal boot from 0xffff0000 */

	regmap_write(syscon, SC_LATCH_ON_RESET, 0x00000040);

	/* Assert ResetReadDone (to avoid hanging in boot ROM) */

	regmap_write(syscon, SC_EFUSE_INT_STATUS, EFUSE_READ_DONE);

	/* Assert chip reset */

	regmap_update_bits(syscon, SC_RESET_CONTROL,

			   RSTCTL_RST_CHIP, RSTCTL_RST_CHIP);

}

static int axxia_reset_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	syscon = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");

	if (IS_ERR(syscon)) {

		pr_err("%s: syscon lookup failed\n", dev->of_node->name);

		return PTR_ERR(syscon);

	}

	arm_pm_restart = do_axxia_restart;

	return 0;

}

static const struct of_device_id of_axxia_reset_match[] = {

	{ .compatible = "lsi,axm55xx-reset", },

	{},

};

MODULE_DEVICE_TABLE(of, of_axxia_reset_match);

static struct platform_driver axxia_reset_driver = {

	.probe = axxia_reset_probe,

	.driver = {

		.name = "axxia-reset",

		.of_match_table = of_match_ptr(of_axxia_reset_match),

	},

};

static int __init axxia_reset_init(void)

{

	return platform_driver_register(&axxia_reset_driver);

}

device_initcall(axxia_reset_init);