1/*
2 * Copyright (C) 2014 STMicroelectronics
3 *
4 * Power off Restart driver, used in STMicroelectronics devices.
5 *
6 * Author: Christophe Kerello <christophe.kerello@st.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2, as
10 * published by the Free Software Foundation.
11 */
12
13#include <linux/module.h>
14#include <linux/of.h>
15#include <linux/of_platform.h>
16#include <linux/platform_device.h>
17#include <linux/mfd/syscon.h>
18#include <linux/reboot.h>
19#include <linux/regmap.h>
20
21struct reset_syscfg {
22	struct regmap *regmap;
23	/* syscfg used for reset */
24	unsigned int offset_rst;
25	unsigned int mask_rst;
26	/* syscfg used for unmask the reset */
27	unsigned int offset_rst_msk;
28	unsigned int mask_rst_msk;
29};
30
31/* STiH415 */
32#define STIH415_SYSCFG_11	0x2c
33#define STIH415_SYSCFG_15	0x3c
34
35static struct reset_syscfg stih415_reset = {
36	.offset_rst = STIH415_SYSCFG_11,
37	.mask_rst = BIT(0),
38	.offset_rst_msk = STIH415_SYSCFG_15,
39	.mask_rst_msk = BIT(0)
40};
41
42/* STiH416 */
43#define STIH416_SYSCFG_500	0x7d0
44#define STIH416_SYSCFG_504	0x7e0
45
46static struct reset_syscfg stih416_reset = {
47	.offset_rst = STIH416_SYSCFG_500,
48	.mask_rst = BIT(0),
49	.offset_rst_msk = STIH416_SYSCFG_504,
50	.mask_rst_msk = BIT(0)
51};
52
53/* STiH407 */
54#define STIH407_SYSCFG_4000	0x0
55#define STIH407_SYSCFG_4008	0x20
56
57static struct reset_syscfg stih407_reset = {
58	.offset_rst = STIH407_SYSCFG_4000,
59	.mask_rst = BIT(0),
60	.offset_rst_msk = STIH407_SYSCFG_4008,
61	.mask_rst_msk = BIT(0)
62};
63
64/* STiD127 */
65#define STID127_SYSCFG_700	0x0
66#define STID127_SYSCFG_773	0x124
67
68static struct reset_syscfg stid127_reset = {
69	.offset_rst = STID127_SYSCFG_773,
70	.mask_rst = BIT(0),
71	.offset_rst_msk = STID127_SYSCFG_700,
72	.mask_rst_msk = BIT(8)
73};
74
75static struct reset_syscfg *st_restart_syscfg;
76
77static int st_restart(struct notifier_block *this, unsigned long mode,
78		      void *cmd)
79{
80	/* reset syscfg updated */
81	regmap_update_bits(st_restart_syscfg->regmap,
82			   st_restart_syscfg->offset_rst,
83			   st_restart_syscfg->mask_rst,
84			   0);
85
86	/* unmask the reset */
87	regmap_update_bits(st_restart_syscfg->regmap,
88			   st_restart_syscfg->offset_rst_msk,
89			   st_restart_syscfg->mask_rst_msk,
90			   0);
91
92	return NOTIFY_DONE;
93}
94
95static struct notifier_block st_restart_nb = {
96	.notifier_call = st_restart,
97	.priority = 192,
98};
99
100static const struct of_device_id st_reset_of_match[] = {
101	{
102		.compatible = "st,stih415-restart",
103		.data = (void *)&stih415_reset,
104	}, {
105		.compatible = "st,stih416-restart",
106		.data = (void *)&stih416_reset,
107	}, {
108		.compatible = "st,stih407-restart",
109		.data = (void *)&stih407_reset,
110	}, {
111		.compatible = "st,stid127-restart",
112		.data = (void *)&stid127_reset,
113	},
114	{}
115};
116
117static int st_reset_probe(struct platform_device *pdev)
118{
119	struct device_node *np = pdev->dev.of_node;
120	const struct of_device_id *match;
121	struct device *dev = &pdev->dev;
122
123	match = of_match_device(st_reset_of_match, dev);
124	if (!match)
125		return -ENODEV;
126
127	st_restart_syscfg = (struct reset_syscfg *)match->data;
128
129	st_restart_syscfg->regmap =
130		syscon_regmap_lookup_by_phandle(np, "st,syscfg");
131	if (IS_ERR(st_restart_syscfg->regmap)) {
132		dev_err(dev, "No syscfg phandle specified\n");
133		return PTR_ERR(st_restart_syscfg->regmap);
134	}
135
136	return register_restart_handler(&st_restart_nb);
137}
138
139static struct platform_driver st_reset_driver = {
140	.probe = st_reset_probe,
141	.driver = {
142		.name = "st_reset",
143		.of_match_table = st_reset_of_match,
144	},
145};
146
147static int __init st_reset_init(void)
148{
149	return platform_driver_register(&st_reset_driver);
150}
151
152device_initcall(st_reset_init);
153
154MODULE_AUTHOR("Christophe Kerello <christophe.kerello@st.com>");
155MODULE_DESCRIPTION("STMicroelectronics Power off Restart driver");
156MODULE_LICENSE("GPL v2");
157