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/regmap.h>
19 
20 #include <asm/system_misc.h>
21 
22 struct reset_syscfg {
23 	struct regmap *regmap;
24 	/* syscfg used for reset */
25 	unsigned int offset_rst;
26 	unsigned int mask_rst;
27 	/* syscfg used for unmask the reset */
28 	unsigned int offset_rst_msk;
29 	unsigned int mask_rst_msk;
30 };
31 
32 /* STiH415 */
33 #define STIH415_SYSCFG_11	0x2c
34 #define STIH415_SYSCFG_15	0x3c
35 
36 static struct reset_syscfg stih415_reset = {
37 	.offset_rst = STIH415_SYSCFG_11,
38 	.mask_rst = BIT(0),
39 	.offset_rst_msk = STIH415_SYSCFG_15,
40 	.mask_rst_msk = BIT(0)
41 };
42 
43 /* STiH416 */
44 #define STIH416_SYSCFG_500	0x7d0
45 #define STIH416_SYSCFG_504	0x7e0
46 
47 static struct reset_syscfg stih416_reset = {
48 	.offset_rst = STIH416_SYSCFG_500,
49 	.mask_rst = BIT(0),
50 	.offset_rst_msk = STIH416_SYSCFG_504,
51 	.mask_rst_msk = BIT(0)
52 };
53 
54 /* STiH407 */
55 #define STIH407_SYSCFG_4000	0x0
56 #define STIH407_SYSCFG_4008	0x20
57 
58 static struct reset_syscfg stih407_reset = {
59 	.offset_rst = STIH407_SYSCFG_4000,
60 	.mask_rst = BIT(0),
61 	.offset_rst_msk = STIH407_SYSCFG_4008,
62 	.mask_rst_msk = BIT(0)
63 };
64 
65 /* STiD127 */
66 #define STID127_SYSCFG_700	0x0
67 #define STID127_SYSCFG_773	0x124
68 
69 static struct reset_syscfg stid127_reset = {
70 	.offset_rst = STID127_SYSCFG_773,
71 	.mask_rst = BIT(0),
72 	.offset_rst_msk = STID127_SYSCFG_700,
73 	.mask_rst_msk = BIT(8)
74 };
75 
76 static struct reset_syscfg *st_restart_syscfg;
77 
78 static void st_restart(enum reboot_mode reboot_mode, const char *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 
93 static struct of_device_id st_reset_of_match[] = {
94 	{
95 		.compatible = "st,stih415-restart",
96 		.data = (void *)&stih415_reset,
97 	}, {
98 		.compatible = "st,stih416-restart",
99 		.data = (void *)&stih416_reset,
100 	}, {
101 		.compatible = "st,stih407-restart",
102 		.data = (void *)&stih407_reset,
103 	}, {
104 		.compatible = "st,stid127-restart",
105 		.data = (void *)&stid127_reset,
106 	},
107 	{}
108 };
109 
110 static int st_reset_probe(struct platform_device *pdev)
111 {
112 	struct device_node *np = pdev->dev.of_node;
113 	const struct of_device_id *match;
114 	struct device *dev = &pdev->dev;
115 
116 	match = of_match_device(st_reset_of_match, dev);
117 	if (!match)
118 		return -ENODEV;
119 
120 	st_restart_syscfg = (struct reset_syscfg *)match->data;
121 
122 	st_restart_syscfg->regmap =
123 		syscon_regmap_lookup_by_phandle(np, "st,syscfg");
124 	if (IS_ERR(st_restart_syscfg->regmap)) {
125 		dev_err(dev, "No syscfg phandle specified\n");
126 		return PTR_ERR(st_restart_syscfg->regmap);
127 	}
128 
129 	arm_pm_restart = st_restart;
130 
131 	return 0;
132 }
133 
134 static struct platform_driver st_reset_driver = {
135 	.probe = st_reset_probe,
136 	.driver = {
137 		.name = "st_reset",
138 		.of_match_table = st_reset_of_match,
139 	},
140 };
141 
142 static int __init st_reset_init(void)
143 {
144 	return platform_driver_register(&st_reset_driver);
145 }
146 
147 device_initcall(st_reset_init);
148 
149 MODULE_AUTHOR("Christophe Kerello <christophe.kerello@st.com>");
150 MODULE_DESCRIPTION("STMicroelectronics Power off Restart driver");
151 MODULE_LICENSE("GPL v2");
152