[mirror_ubuntu-bionic-kernel.git] / drivers / power / reset / axxia-reset.c

/*
 * 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/notifier.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/regmap.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 int axxia_restart_handler(struct notifier_block *this,
				 unsigned long mode, void *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);

	return NOTIFY_DONE;
}

static struct notifier_block axxia_restart_nb = {
	.notifier_call = axxia_restart_handler,
	.priority = 128,
};

static int axxia_reset_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	int err;

	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);
	}

	err = register_restart_handler(&axxia_restart_nb);
	if (err)
		dev_err(dev, "cannot register restart handler (err=%d)\n", err);

	return err;
}

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);
Commit	Line	Data
4a315e34 AB	1	/*
	2	* Reset driver for Axxia devices
	3	*
	4	* Copyright (C) 2014 LSI
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 and
	8	* only version 2 as published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	*/
	16	#include <linux/init.h>
	17	#include <linux/err.h>
	18	#include <linux/io.h>
	19	#include <linux/kernel.h>
	20	#include <linux/mfd/syscon.h>
	21	#include <linux/module.h>
fcf01c51	22	#include <linux/notifier.h>
4a315e34 AB	23	#include <linux/of.h>
	24	#include <linux/platform_device.h>
	25	#include <linux/reboot.h>
	26	#include <linux/regmap.h>
	27
4a315e34 AB	28	#define SC_CRIT_WRITE_KEY 0x1000
	29	#define SC_LATCH_ON_RESET 0x1004
	30	#define SC_RESET_CONTROL 0x1008
	31	#define RSTCTL_RST_ZERO (1<<3)
	32	#define RSTCTL_RST_FAB (1<<2)
	33	#define RSTCTL_RST_CHIP (1<<1)
	34	#define RSTCTL_RST_SYS (1<<0)
	35	#define SC_EFUSE_INT_STATUS 0x180c
	36	#define EFUSE_READ_DONE (1<<31)
	37
	38	static struct regmap *syscon;
	39
fcf01c51 GR	40	static int axxia_restart_handler(struct notifier_block *this,
fcf01c51 GR	41	unsigned long mode, void *cmd)
4a315e34 AB	42	{
	43	/* Access Key (0xab) */
	44	regmap_write(syscon, SC_CRIT_WRITE_KEY, 0xab);
	45	/* Select internal boot from 0xffff0000 */
	46	regmap_write(syscon, SC_LATCH_ON_RESET, 0x00000040);
	47	/* Assert ResetReadDone (to avoid hanging in boot ROM) */
	48	regmap_write(syscon, SC_EFUSE_INT_STATUS, EFUSE_READ_DONE);
	49	/* Assert chip reset */
	50	regmap_update_bits(syscon, SC_RESET_CONTROL,
	51	RSTCTL_RST_CHIP, RSTCTL_RST_CHIP);
fcf01c51 GR	52
fcf01c51 GR	53	return NOTIFY_DONE;
4a315e34 AB	54	}
4a315e34 AB	55
fcf01c51 GR	56	static struct notifier_block axxia_restart_nb = {
	57	.notifier_call = axxia_restart_handler,
	58	.priority = 128,
	59	};
	60
4a315e34 AB	61	static int axxia_reset_probe(struct platform_device *pdev)
	62	{
	63	struct device *dev = &pdev->dev;
fcf01c51	64	int err;
4a315e34 AB	65
	66	syscon = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");
	67	if (IS_ERR(syscon)) {
	68	pr_err("%s: syscon lookup failed\n", dev->of_node->name);
	69	return PTR_ERR(syscon);
	70	}
	71
fcf01c51 GR	72	err = register_restart_handler(&axxia_restart_nb);
	73	if (err)
	74	dev_err(dev, "cannot register restart handler (err=%d)\n", err);
4a315e34	75
fcf01c51	76	return err;
4a315e34 AB	77	}
	78
	79	static const struct of_device_id of_axxia_reset_match[] = {
	80	{ .compatible = "lsi,axm55xx-reset", },
	81	{},
	82	};
	83	MODULE_DEVICE_TABLE(of, of_axxia_reset_match);
	84
	85	static struct platform_driver axxia_reset_driver = {
	86	.probe = axxia_reset_probe,
	87	.driver = {
	88	.name = "axxia-reset",
	89	.of_match_table = of_match_ptr(of_axxia_reset_match),
	90	},
	91	};
	92
	93	static int __init axxia_reset_init(void)
	94	{
	95	return platform_driver_register(&axxia_reset_driver);
	96	}
	97	device_initcall(axxia_reset_init);