1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2014 STMicroelectronics
4 *
5 * Power off Restart driver, used in STMicroelectronics devices.
6 *
7 * Author: Christophe Kerello <christophe.kerello@st.com>
8 */
9
10 #include <linux/module.h>
11 #include <linux/of.h>
12 #include <linux/of_platform.h>
13 #include <linux/platform_device.h>
14 #include <linux/mfd/syscon.h>
15 #include <linux/reboot.h>
16 #include <linux/regmap.h>
17
18 struct reset_syscfg {
19 struct regmap *regmap;
20 /* syscfg used for reset */
21 unsigned int offset_rst;
22 unsigned int mask_rst;
23 /* syscfg used for unmask the reset */
24 unsigned int offset_rst_msk;
25 unsigned int mask_rst_msk;
26 };
27
28 /* STiH407 */
29 #define STIH407_SYSCFG_4000 0x0
30 #define STIH407_SYSCFG_4008 0x20
31
32 static struct reset_syscfg stih407_reset = {
33 .offset_rst = STIH407_SYSCFG_4000,
34 .mask_rst = BIT(0),
35 .offset_rst_msk = STIH407_SYSCFG_4008,
36 .mask_rst_msk = BIT(0)
37 };
38
39
40 static struct reset_syscfg *st_restart_syscfg;
41
st_restart(struct notifier_block * this,unsigned long mode,void * cmd)42 static int st_restart(struct notifier_block *this, unsigned long mode,
43 void *cmd)
44 {
45 /* reset syscfg updated */
46 regmap_update_bits(st_restart_syscfg->regmap,
47 st_restart_syscfg->offset_rst,
48 st_restart_syscfg->mask_rst,
49 0);
50
51 /* unmask the reset */
52 regmap_update_bits(st_restart_syscfg->regmap,
53 st_restart_syscfg->offset_rst_msk,
54 st_restart_syscfg->mask_rst_msk,
55 0);
56
57 return NOTIFY_DONE;
58 }
59
60 static struct notifier_block st_restart_nb = {
61 .notifier_call = st_restart,
62 .priority = 192,
63 };
64
65 static const struct of_device_id st_reset_of_match[] = {
66 {
67 .compatible = "st,stih407-restart",
68 .data = (void *)&stih407_reset,
69 },
70 {}
71 };
72
st_reset_probe(struct platform_device * pdev)73 static int st_reset_probe(struct platform_device *pdev)
74 {
75 struct device_node *np = pdev->dev.of_node;
76 const struct of_device_id *match;
77 struct device *dev = &pdev->dev;
78
79 match = of_match_device(st_reset_of_match, dev);
80 if (!match)
81 return -ENODEV;
82
83 st_restart_syscfg = (struct reset_syscfg *)match->data;
84
85 st_restart_syscfg->regmap =
86 syscon_regmap_lookup_by_phandle(np, "st,syscfg");
87 if (IS_ERR(st_restart_syscfg->regmap)) {
88 dev_err(dev, "No syscfg phandle specified\n");
89 return PTR_ERR(st_restart_syscfg->regmap);
90 }
91
92 return register_restart_handler(&st_restart_nb);
93 }
94
95 static struct platform_driver st_reset_driver = {
96 .probe = st_reset_probe,
97 .driver = {
98 .name = "st_reset",
99 .of_match_table = st_reset_of_match,
100 },
101 };
102
st_reset_init(void)103 static int __init st_reset_init(void)
104 {
105 return platform_driver_register(&st_reset_driver);
106 }
107
108 device_initcall(st_reset_init);
109
110 MODULE_AUTHOR("Christophe Kerello <christophe.kerello@st.com>");
111 MODULE_DESCRIPTION("STMicroelectronics Power off Restart driver");
112 MODULE_LICENSE("GPL v2");
113