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 else if (of_property_read_bool(np, "native-endian"))
79 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
80
81 /*
82 * search for reg-io-width property in DT. If it is not provided,
83 * default to 4 bytes. regmap_init_mmio will return an error if values
84 * are invalid so there is no need to check them here.
85 */
86 ret = of_property_read_u32(np, "reg-io-width", ®_io_width);
87 if (ret)
88 reg_io_width = 4;
89
90 syscon_config.reg_stride = reg_io_width;
91 syscon_config.val_bits = reg_io_width * 8;
92 syscon_config.max_register = resource_size(&res) - reg_io_width;
93
94 regmap = regmap_init_mmio(NULL, base, &syscon_config);
95 if (IS_ERR(regmap)) {
96 pr_err("regmap init failed\n");
97 ret = PTR_ERR(regmap);
98 goto err_regmap;
99 }
100
101 syscon->regmap = regmap;
102 syscon->np = np;
103
104 spin_lock(&syscon_list_slock);
105 list_add_tail(&syscon->list, &syscon_list);
106 spin_unlock(&syscon_list_slock);
107
108 return syscon;
109
110err_regmap:
111 iounmap(base);
112err_map:
113 kfree(syscon);
114 return ERR_PTR(ret);
115}
116
117struct regmap *syscon_node_to_regmap(struct device_node *np)
118{
119 struct syscon *entry, *syscon = NULL;
120
121 spin_lock(&syscon_list_slock);
122
123 list_for_each_entry(entry, &syscon_list, list)
124 if (entry->np == np) {
125 syscon = entry;
126 break;
127 }
128
129 spin_unlock(&syscon_list_slock);
130
131 if (!syscon)
132 syscon = of_syscon_register(np);
133
134 if (IS_ERR(syscon))
135 return ERR_CAST(syscon);
136
137 return syscon->regmap;
138}
139EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
140
141struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
142{
143 struct device_node *syscon_np;
144 struct regmap *regmap;
145
146 syscon_np = of_find_compatible_node(NULL, NULL, s);
147 if (!syscon_np)
148 return ERR_PTR(-ENODEV);
149
150 regmap = syscon_node_to_regmap(syscon_np);
151 of_node_put(syscon_np);
152
153 return regmap;
154}
155EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
156
157static int syscon_match_pdevname(struct device *dev, void *data)
158{
159 return !strcmp(dev_name(dev), (const char *)data);
160}
161
162struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
163{
164 struct device *dev;
165 struct syscon *syscon;
166
167 dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
168 syscon_match_pdevname);
169 if (!dev)
170 return ERR_PTR(-EPROBE_DEFER);
171
172 syscon = dev_get_drvdata(dev);
173
174 return syscon->regmap;
175}
176EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
177
178struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
179 const char *property)
180{
181 struct device_node *syscon_np;
182 struct regmap *regmap;
183
184 if (property)
185 syscon_np = of_parse_phandle(np, property, 0);
186 else
187 syscon_np = np;
188
189 if (!syscon_np)
190 return ERR_PTR(-ENODEV);
191
192 regmap = syscon_node_to_regmap(syscon_np);
193 of_node_put(syscon_np);
194
195 return regmap;
196}
197EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
198
199static int syscon_probe(struct platform_device *pdev)
200{
201 struct device *dev = &pdev->dev;
202 struct syscon_platform_data *pdata = dev_get_platdata(dev);
203 struct syscon *syscon;
204 struct regmap_config syscon_config = syscon_regmap_config;
205 struct resource *res;
206 void __iomem *base;
207
208 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
209 if (!syscon)
210 return -ENOMEM;
211
212 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
213 if (!res)
214 return -ENOENT;
215
216 base = devm_ioremap(dev, res->start, resource_size(res));
217 if (!base)
218 return -ENOMEM;
219
220 syscon_config.max_register = res->end - res->start - 3;
221 if (pdata)
222 syscon_config.name = pdata->label;
223 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
224 if (IS_ERR(syscon->regmap)) {
225 dev_err(dev, "regmap init failed\n");
226 return PTR_ERR(syscon->regmap);
227 }
228
229 platform_set_drvdata(pdev, syscon);
230
231 dev_dbg(dev, "regmap %pR registered\n", res);
232
233 return 0;
234}
235
236static const struct platform_device_id syscon_ids[] = {
237 { "syscon", },
238 { }
239};
240
241static struct platform_driver syscon_driver = {
242 .driver = {
243 .name = "syscon",
244 },
245 .probe = syscon_probe,
246 .id_table = syscon_ids,
247};
248
249static int __init syscon_init(void)
250{
251 return platform_driver_register(&syscon_driver);
252}
253postcore_initcall(syscon_init);
254
255static void __exit syscon_exit(void)
256{
257 platform_driver_unregister(&syscon_driver);
258}
259module_exit(syscon_exit);
260
261MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
262MODULE_DESCRIPTION("System Control driver");
263MODULE_LICENSE("GPL v2");