Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * System Control Driver
3 *
4 * Copyright (C) 2012 Freescale Semiconductor, Inc.
5 * Copyright (C) 2012 Linaro Ltd.
6 *
7 * Author: Dong Aisheng <dong.aisheng@linaro.org>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 */
14
15#include <linux/err.h>
16#include <linux/io.h>
17#include <linux/module.h>
18#include <linux/of.h>
19#include <linux/of_address.h>
20#include <linux/of_platform.h>
21#include <linux/platform_device.h>
22#include <linux/regmap.h>
23
24static struct platform_driver syscon_driver;
25
26struct syscon {
27 struct device *dev;
28 void __iomem *base;
29 struct regmap *regmap;
30};
31
32static int syscon_match(struct device *dev, void *data)
33{
34 struct syscon *syscon = dev_get_drvdata(dev);
35 struct device_node *dn = data;
36
37 return (syscon->dev->of_node == dn) ? 1 : 0;
38}
39
40struct regmap *syscon_node_to_regmap(struct device_node *np)
41{
42 struct syscon *syscon;
43 struct device *dev;
44
45 dev = driver_find_device(&syscon_driver.driver, NULL, np,
46 syscon_match);
47 if (!dev)
48 return ERR_PTR(-EPROBE_DEFER);
49
50 syscon = dev_get_drvdata(dev);
51
52 return syscon->regmap;
53}
54EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
55
56struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
57{
58 struct device_node *syscon_np;
59 struct regmap *regmap;
60
61 syscon_np = of_find_compatible_node(NULL, NULL, s);
62 if (!syscon_np)
63 return ERR_PTR(-ENODEV);
64
65 regmap = syscon_node_to_regmap(syscon_np);
66 of_node_put(syscon_np);
67
68 return regmap;
69}
70EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
71
72struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
73 const char *property)
74{
75 struct device_node *syscon_np;
76 struct regmap *regmap;
77
78 syscon_np = of_parse_phandle(np, property, 0);
79 if (!syscon_np)
80 return ERR_PTR(-ENODEV);
81
82 regmap = syscon_node_to_regmap(syscon_np);
83 of_node_put(syscon_np);
84
85 return regmap;
86}
87EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
88
89static const struct of_device_id of_syscon_match[] = {
90 { .compatible = "syscon", },
91 { },
92};
93
94static struct regmap_config syscon_regmap_config = {
95 .reg_bits = 32,
96 .val_bits = 32,
97 .reg_stride = 4,
98};
99
100static int __devinit syscon_probe(struct platform_device *pdev)
101{
102 struct device *dev = &pdev->dev;
103 struct device_node *np = dev->of_node;
104 struct syscon *syscon;
105 struct resource res;
106 int ret;
107
108 if (!np)
109 return -ENOENT;
110
111 syscon = devm_kzalloc(dev, sizeof(struct syscon),
112 GFP_KERNEL);
113 if (!syscon)
114 return -ENOMEM;
115
116 syscon->base = of_iomap(np, 0);
117 if (!syscon->base)
118 return -EADDRNOTAVAIL;
119
120 ret = of_address_to_resource(np, 0, &res);
121 if (ret)
122 return ret;
123
124 syscon_regmap_config.max_register = res.end - res.start - 3;
125 syscon->regmap = devm_regmap_init_mmio(dev, syscon->base,
126 &syscon_regmap_config);
127 if (IS_ERR(syscon->regmap)) {
128 dev_err(dev, "regmap init failed\n");
129 return PTR_ERR(syscon->regmap);
130 }
131
132 syscon->dev = dev;
133 platform_set_drvdata(pdev, syscon);
134
135 dev_info(dev, "syscon regmap start 0x%x end 0x%x registered\n",
136 res.start, res.end);
137
138 return 0;
139}
140
141static int __devexit syscon_remove(struct platform_device *pdev)
142{
143 struct syscon *syscon;
144
145 syscon = platform_get_drvdata(pdev);
146 iounmap(syscon->base);
147 platform_set_drvdata(pdev, NULL);
148
149 return 0;
150}
151
152static struct platform_driver syscon_driver = {
153 .driver = {
154 .name = "syscon",
155 .owner = THIS_MODULE,
156 .of_match_table = of_syscon_match,
157 },
158 .probe = syscon_probe,
159 .remove = __devexit_p(syscon_remove),
160};
161
162static int __init syscon_init(void)
163{
164 return platform_driver_register(&syscon_driver);
165}
166postcore_initcall(syscon_init);
167
168static void __exit syscon_exit(void)
169{
170 platform_driver_unregister(&syscon_driver);
171}
172module_exit(syscon_exit);
173
174MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
175MODULE_DESCRIPTION("System Control driver");
176MODULE_LICENSE("GPL v2");