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/list.h>
19#include <linux/of.h>
20#include <linux/of_address.h>
21#include <linux/of_platform.h>
22#include <linux/platform_data/syscon.h>
23#include <linux/platform_device.h>
24#include <linux/regmap.h>
25#include <linux/mfd/syscon.h>
26#include <linux/slab.h>
27
28static struct platform_driver syscon_driver;
29
30static DEFINE_SPINLOCK(syscon_list_slock);
31static LIST_HEAD(syscon_list);
32
33struct syscon {
34 struct device_node *np;
35 struct regmap *regmap;
36 struct list_head list;
37};
38
39static const struct regmap_config syscon_regmap_config = {
40 .reg_bits = 32,
41 .val_bits = 32,
42 .reg_stride = 4,
43};
44
45static struct syscon *of_syscon_register(struct device_node *np)
46{
47 struct syscon *syscon;
48 struct regmap *regmap;
49 void __iomem *base;
50 u32 reg_io_width;
51 int ret;
52 struct regmap_config syscon_config = syscon_regmap_config;
53 struct resource res;
54
55 if (!of_device_is_compatible(np, "syscon"))
56 return ERR_PTR(-EINVAL);
57
58 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
59 if (!syscon)
60 return ERR_PTR(-ENOMEM);
61
62 if (of_address_to_resource(np, 0, &res)) {
63 ret = -ENOMEM;
64 goto err_map;
65 }
66
67 base = ioremap(res.start, resource_size(&res));
68 if (!base) {
69 ret = -ENOMEM;
70 goto err_map;
71 }
72
73 /* Parse the device's DT node for an endianness specification */
74 if (of_property_read_bool(np, "big-endian"))
75 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
76 else if (of_property_read_bool(np, "little-endian"))
77 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
78
79 /*
80 * search for reg-io-width property in DT. If it is not provided,
81 * default to 4 bytes. regmap_init_mmio will return an error if values
82 * are invalid so there is no need to check them here.
83 */
84 ret = of_property_read_u32(np, "reg-io-width", ®_io_width);
85 if (ret)
86 reg_io_width = 4;
87
88 syscon_config.reg_stride = reg_io_width;
89 syscon_config.val_bits = reg_io_width * 8;
90 syscon_config.max_register = resource_size(&res) - reg_io_width;
91
92 regmap = regmap_init_mmio(NULL, base, &syscon_config);
93 if (IS_ERR(regmap)) {
94 pr_err("regmap init failed\n");
95 ret = PTR_ERR(regmap);
96 goto err_regmap;
97 }
98
99 syscon->regmap = regmap;
100 syscon->np = np;
101
102 spin_lock(&syscon_list_slock);
103 list_add_tail(&syscon->list, &syscon_list);
104 spin_unlock(&syscon_list_slock);
105
106 return syscon;
107
108err_regmap:
109 iounmap(base);
110err_map:
111 kfree(syscon);
112 return ERR_PTR(ret);
113}
114
115struct regmap *syscon_node_to_regmap(struct device_node *np)
116{
117 struct syscon *entry, *syscon = NULL;
118
119 spin_lock(&syscon_list_slock);
120
121 list_for_each_entry(entry, &syscon_list, list)
122 if (entry->np == np) {
123 syscon = entry;
124 break;
125 }
126
127 spin_unlock(&syscon_list_slock);
128
129 if (!syscon)
130 syscon = of_syscon_register(np);
131
132 if (IS_ERR(syscon))
133 return ERR_CAST(syscon);
134
135 return syscon->regmap;
136}
137EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
138
139struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
140{
141 struct device_node *syscon_np;
142 struct regmap *regmap;
143
144 syscon_np = of_find_compatible_node(NULL, NULL, s);
145 if (!syscon_np)
146 return ERR_PTR(-ENODEV);
147
148 regmap = syscon_node_to_regmap(syscon_np);
149 of_node_put(syscon_np);
150
151 return regmap;
152}
153EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
154
155static int syscon_match_pdevname(struct device *dev, void *data)
156{
157 return !strcmp(dev_name(dev), (const char *)data);
158}
159
160struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
161{
162 struct device *dev;
163 struct syscon *syscon;
164
165 dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
166 syscon_match_pdevname);
167 if (!dev)
168 return ERR_PTR(-EPROBE_DEFER);
169
170 syscon = dev_get_drvdata(dev);
171
172 return syscon->regmap;
173}
174EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
175
176struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
177 const char *property)
178{
179 struct device_node *syscon_np;
180 struct regmap *regmap;
181
182 if (property)
183 syscon_np = of_parse_phandle(np, property, 0);
184 else
185 syscon_np = np;
186
187 if (!syscon_np)
188 return ERR_PTR(-ENODEV);
189
190 regmap = syscon_node_to_regmap(syscon_np);
191 of_node_put(syscon_np);
192
193 return regmap;
194}
195EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
196
197static int syscon_probe(struct platform_device *pdev)
198{
199 struct device *dev = &pdev->dev;
200 struct syscon_platform_data *pdata = dev_get_platdata(dev);
201 struct syscon *syscon;
202 struct regmap_config syscon_config = syscon_regmap_config;
203 struct resource *res;
204 void __iomem *base;
205
206 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
207 if (!syscon)
208 return -ENOMEM;
209
210 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
211 if (!res)
212 return -ENOENT;
213
214 base = devm_ioremap(dev, res->start, resource_size(res));
215 if (!base)
216 return -ENOMEM;
217
218 syscon_config.max_register = res->end - res->start - 3;
219 if (pdata)
220 syscon_config.name = pdata->label;
221 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
222 if (IS_ERR(syscon->regmap)) {
223 dev_err(dev, "regmap init failed\n");
224 return PTR_ERR(syscon->regmap);
225 }
226
227 platform_set_drvdata(pdev, syscon);
228
229 dev_dbg(dev, "regmap %pR registered\n", res);
230
231 return 0;
232}
233
234static const struct platform_device_id syscon_ids[] = {
235 { "syscon", },
236 { }
237};
238
239static struct platform_driver syscon_driver = {
240 .driver = {
241 .name = "syscon",
242 },
243 .probe = syscon_probe,
244 .id_table = syscon_ids,
245};
246
247static int __init syscon_init(void)
248{
249 return platform_driver_register(&syscon_driver);
250}
251postcore_initcall(syscon_init);
252
253static void __exit syscon_exit(void)
254{
255 platform_driver_unregister(&syscon_driver);
256}
257module_exit(syscon_exit);
258
259MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
260MODULE_DESCRIPTION("System Control driver");
261MODULE_LICENSE("GPL v2");