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/hwspinlock.h>
17 #include <linux/io.h>
18 #include <linux/module.h>
19 #include <linux/list.h>
20 #include <linux/of.h>
21 #include <linux/of_address.h>
22 #include <linux/of_platform.h>
23 #include <linux/platform_data/syscon.h>
24 #include <linux/platform_device.h>
25 #include <linux/regmap.h>
26 #include <linux/mfd/syscon.h>
27 #include <linux/slab.h>
28
29 static struct platform_driver syscon_driver;
30
31 static DEFINE_SPINLOCK(syscon_list_slock);
32 static LIST_HEAD(syscon_list);
33
34 struct syscon {
35 struct device_node *np;
36 struct regmap *regmap;
37 struct list_head list;
38 };
39
40 static const struct regmap_config syscon_regmap_config = {
41 .reg_bits = 32,
42 .val_bits = 32,
43 .reg_stride = 4,
44 };
45
of_syscon_register(struct device_node * np)46 static struct syscon *of_syscon_register(struct device_node *np)
47 {
48 struct syscon *syscon;
49 struct regmap *regmap;
50 void __iomem *base;
51 u32 reg_io_width;
52 int ret;
53 struct regmap_config syscon_config = syscon_regmap_config;
54 struct resource res;
55
56 if (!of_device_is_compatible(np, "syscon"))
57 return ERR_PTR(-EINVAL);
58
59 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
60 if (!syscon)
61 return ERR_PTR(-ENOMEM);
62
63 if (of_address_to_resource(np, 0, &res)) {
64 ret = -ENOMEM;
65 goto err_map;
66 }
67
68 base = ioremap(res.start, resource_size(&res));
69 if (!base) {
70 ret = -ENOMEM;
71 goto err_map;
72 }
73
74 /* Parse the device's DT node for an endianness specification */
75 if (of_property_read_bool(np, "big-endian"))
76 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
77 else if (of_property_read_bool(np, "little-endian"))
78 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
79 else if (of_property_read_bool(np, "native-endian"))
80 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
81
82 /*
83 * search for reg-io-width property in DT. If it is not provided,
84 * default to 4 bytes. regmap_init_mmio will return an error if values
85 * are invalid so there is no need to check them here.
86 */
87 ret = of_property_read_u32(np, "reg-io-width", ®_io_width);
88 if (ret)
89 reg_io_width = 4;
90
91 ret = of_hwspin_lock_get_id(np, 0);
92 if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
93 syscon_config.use_hwlock = true;
94 syscon_config.hwlock_id = ret;
95 syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
96 } else if (ret < 0) {
97 switch (ret) {
98 case -ENOENT:
99 /* Ignore missing hwlock, it's optional. */
100 break;
101 default:
102 pr_err("Failed to retrieve valid hwlock: %d\n", ret);
103 /* fall-through */
104 case -EPROBE_DEFER:
105 goto err_regmap;
106 }
107 }
108
109 syscon_config.name = of_node_full_name(np);
110 syscon_config.reg_stride = reg_io_width;
111 syscon_config.val_bits = reg_io_width * 8;
112 syscon_config.max_register = resource_size(&res) - reg_io_width;
113 syscon_config.name = of_node_full_name(np);
114
115 regmap = regmap_init_mmio(NULL, base, &syscon_config);
116 if (IS_ERR(regmap)) {
117 pr_err("regmap init failed\n");
118 ret = PTR_ERR(regmap);
119 goto err_regmap;
120 }
121
122 syscon->regmap = regmap;
123 syscon->np = np;
124
125 spin_lock(&syscon_list_slock);
126 list_add_tail(&syscon->list, &syscon_list);
127 spin_unlock(&syscon_list_slock);
128
129 return syscon;
130
131 err_regmap:
132 iounmap(base);
133 err_map:
134 kfree(syscon);
135 return ERR_PTR(ret);
136 }
137
syscon_node_to_regmap(struct device_node * np)138 struct regmap *syscon_node_to_regmap(struct device_node *np)
139 {
140 struct syscon *entry, *syscon = NULL;
141
142 spin_lock(&syscon_list_slock);
143
144 list_for_each_entry(entry, &syscon_list, list)
145 if (entry->np == np) {
146 syscon = entry;
147 break;
148 }
149
150 spin_unlock(&syscon_list_slock);
151
152 if (!syscon)
153 syscon = of_syscon_register(np);
154
155 if (IS_ERR(syscon))
156 return ERR_CAST(syscon);
157
158 return syscon->regmap;
159 }
160 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
161
syscon_regmap_lookup_by_compatible(const char * s)162 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
163 {
164 struct device_node *syscon_np;
165 struct regmap *regmap;
166
167 syscon_np = of_find_compatible_node(NULL, NULL, s);
168 if (!syscon_np)
169 return ERR_PTR(-ENODEV);
170
171 regmap = syscon_node_to_regmap(syscon_np);
172 of_node_put(syscon_np);
173
174 return regmap;
175 }
176 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
177
syscon_match_pdevname(struct device * dev,void * data)178 static int syscon_match_pdevname(struct device *dev, void *data)
179 {
180 return !strcmp(dev_name(dev), (const char *)data);
181 }
182
syscon_regmap_lookup_by_pdevname(const char * s)183 struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
184 {
185 struct device *dev;
186 struct syscon *syscon;
187
188 dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
189 syscon_match_pdevname);
190 if (!dev)
191 return ERR_PTR(-EPROBE_DEFER);
192
193 syscon = dev_get_drvdata(dev);
194
195 return syscon->regmap;
196 }
197 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
198
syscon_regmap_lookup_by_phandle(struct device_node * np,const char * property)199 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
200 const char *property)
201 {
202 struct device_node *syscon_np;
203 struct regmap *regmap;
204
205 if (property)
206 syscon_np = of_parse_phandle(np, property, 0);
207 else
208 syscon_np = np;
209
210 if (!syscon_np)
211 return ERR_PTR(-ENODEV);
212
213 regmap = syscon_node_to_regmap(syscon_np);
214 of_node_put(syscon_np);
215
216 return regmap;
217 }
218 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
219
syscon_probe(struct platform_device * pdev)220 static int syscon_probe(struct platform_device *pdev)
221 {
222 struct device *dev = &pdev->dev;
223 struct syscon_platform_data *pdata = dev_get_platdata(dev);
224 struct syscon *syscon;
225 struct regmap_config syscon_config = syscon_regmap_config;
226 struct resource *res;
227 void __iomem *base;
228
229 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
230 if (!syscon)
231 return -ENOMEM;
232
233 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
234 if (!res)
235 return -ENOENT;
236
237 base = devm_ioremap(dev, res->start, resource_size(res));
238 if (!base)
239 return -ENOMEM;
240
241 syscon_config.max_register = res->end - res->start - 3;
242 if (pdata)
243 syscon_config.name = pdata->label;
244 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
245 if (IS_ERR(syscon->regmap)) {
246 dev_err(dev, "regmap init failed\n");
247 return PTR_ERR(syscon->regmap);
248 }
249
250 platform_set_drvdata(pdev, syscon);
251
252 dev_dbg(dev, "regmap %pR registered\n", res);
253
254 return 0;
255 }
256
257 static const struct platform_device_id syscon_ids[] = {
258 { "syscon", },
259 { }
260 };
261
262 static struct platform_driver syscon_driver = {
263 .driver = {
264 .name = "syscon",
265 },
266 .probe = syscon_probe,
267 .id_table = syscon_ids,
268 };
269
syscon_init(void)270 static int __init syscon_init(void)
271 {
272 return platform_driver_register(&syscon_driver);
273 }
274 postcore_initcall(syscon_init);
275
syscon_exit(void)276 static void __exit syscon_exit(void)
277 {
278 platform_driver_unregister(&syscon_driver);
279 }
280 module_exit(syscon_exit);
281
282 MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
283 MODULE_DESCRIPTION("System Control driver");
284 MODULE_LICENSE("GPL v2");
285
