tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License version 2 as
4 * published by the Free Software Foundation.
5 *
6 * This program is distributed in the hope that it will be useful,
7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9 * GNU General Public License for more details.
10 *
11 * Copyright (C) 2012 ARM Limited
12 */
13
14#include <linux/delay.h>
15#include <linux/notifier.h>
16#include <linux/of.h>
17#include <linux/of_device.h>
18#include <linux/platform_device.h>
19#include <linux/reboot.h>
20#include <linux/stat.h>
21#include <linux/vexpress.h>
22
23static void vexpress_reset_do(struct device *dev, const char *what)
24{
25 int err = -ENOENT;
26 struct regmap *reg = dev_get_drvdata(dev);
27
28 if (reg) {
29 err = regmap_write(reg, 0, 0);
30 if (!err)
31 mdelay(1000);
32 }
33
34 dev_emerg(dev, "Unable to %s (%d)\n", what, err);
35}
36
37static struct device *vexpress_power_off_device;
38
39static void vexpress_power_off(void)
40{
41 vexpress_reset_do(vexpress_power_off_device, "power off");
42}
43
44static struct device *vexpress_restart_device;
45
46static int vexpress_restart(struct notifier_block *this, unsigned long mode,
47 void *cmd)
48{
49 vexpress_reset_do(vexpress_restart_device, "restart");
50
51 return NOTIFY_DONE;
52}
53
54static struct notifier_block vexpress_restart_nb = {
55 .notifier_call = vexpress_restart,
56 .priority = 128,
57};
58
59static ssize_t vexpress_reset_active_show(struct device *dev,
60 struct device_attribute *attr, char *buf)
61{
62 return sprintf(buf, "%d\n", vexpress_restart_device == dev);
63}
64
65static ssize_t vexpress_reset_active_store(struct device *dev,
66 struct device_attribute *attr, const char *buf, size_t count)
67{
68 long value;
69 int err = kstrtol(buf, 0, &value);
70
71 if (!err && value)
72 vexpress_restart_device = dev;
73
74 return err ? err : count;
75}
76
77static DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show,
78 vexpress_reset_active_store);
79
80
81enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT };
82
83static const struct of_device_id vexpress_reset_of_match[] = {
84 {
85 .compatible = "arm,vexpress-reset",
86 .data = (void *)FUNC_RESET,
87 }, {
88 .compatible = "arm,vexpress-shutdown",
89 .data = (void *)FUNC_SHUTDOWN
90 }, {
91 .compatible = "arm,vexpress-reboot",
92 .data = (void *)FUNC_REBOOT
93 },
94 {}
95};
96
97static int _vexpress_register_restart_handler(struct device *dev)
98{
99 int err;
100
101 vexpress_restart_device = dev;
102 err = register_restart_handler(&vexpress_restart_nb);
103 if (err) {
104 dev_err(dev, "cannot register restart handler (err=%d)\n", err);
105 return err;
106 }
107 device_create_file(dev, &dev_attr_active);
108
109 return 0;
110}
111
112static int vexpress_reset_probe(struct platform_device *pdev)
113{
114 const struct of_device_id *match =
115 of_match_device(vexpress_reset_of_match, &pdev->dev);
116 struct regmap *regmap;
117 int ret = 0;
118
119 if (!match)
120 return -EINVAL;
121
122 regmap = devm_regmap_init_vexpress_config(&pdev->dev);
123 if (IS_ERR(regmap))
124 return PTR_ERR(regmap);
125 dev_set_drvdata(&pdev->dev, regmap);
126
127 switch ((enum vexpress_reset_func)match->data) {
128 case FUNC_SHUTDOWN:
129 vexpress_power_off_device = &pdev->dev;
130 pm_power_off = vexpress_power_off;
131 break;
132 case FUNC_RESET:
133 if (!vexpress_restart_device)
134 ret = _vexpress_register_restart_handler(&pdev->dev);
135 break;
136 case FUNC_REBOOT:
137 ret = _vexpress_register_restart_handler(&pdev->dev);
138 break;
139 };
140
141 return ret;
142}
143
144static struct platform_driver vexpress_reset_driver = {
145 .probe = vexpress_reset_probe,
146 .driver = {
147 .name = "vexpress-reset",
148 .of_match_table = vexpress_reset_of_match,
149 },
150};
151
152static int __init vexpress_reset_init(void)
153{
154 return platform_driver_register(&vexpress_reset_driver);
155}
156device_initcall(vexpress_reset_init);