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Linux/drivers/mfd/syscon.c

  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 
 28 static struct platform_driver syscon_driver;
 29 
 30 static DEFINE_SPINLOCK(syscon_list_slock);
 31 static LIST_HEAD(syscon_list);
 32 
 33 struct syscon {
 34         struct device_node *np;
 35         struct regmap *regmap;
 36         struct list_head list;
 37 };
 38 
 39 static struct regmap_config syscon_regmap_config = {
 40         .reg_bits = 32,
 41         .val_bits = 32,
 42         .reg_stride = 4,
 43 };
 44 
 45 static struct syscon *of_syscon_register(struct device_node *np)
 46 {
 47         struct syscon *syscon;
 48         struct regmap *regmap;
 49         void __iomem *base;
 50         int ret;
 51         struct regmap_config syscon_config = syscon_regmap_config;
 52 
 53         if (!of_device_is_compatible(np, "syscon"))
 54                 return ERR_PTR(-EINVAL);
 55 
 56         syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
 57         if (!syscon)
 58                 return ERR_PTR(-ENOMEM);
 59 
 60         base = of_iomap(np, 0);
 61         if (!base) {
 62                 ret = -ENOMEM;
 63                 goto err_map;
 64         }
 65 
 66         /* Parse the device's DT node for an endianness specification */
 67         if (of_property_read_bool(np, "big-endian"))
 68                 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
 69          else if (of_property_read_bool(np, "little-endian"))
 70                 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
 71 
 72         regmap = regmap_init_mmio(NULL, base, &syscon_config);
 73         if (IS_ERR(regmap)) {
 74                 pr_err("regmap init failed\n");
 75                 ret = PTR_ERR(regmap);
 76                 goto err_regmap;
 77         }
 78 
 79         syscon->regmap = regmap;
 80         syscon->np = np;
 81 
 82         spin_lock(&syscon_list_slock);
 83         list_add_tail(&syscon->list, &syscon_list);
 84         spin_unlock(&syscon_list_slock);
 85 
 86         return syscon;
 87 
 88 err_regmap:
 89         iounmap(base);
 90 err_map:
 91         kfree(syscon);
 92         return ERR_PTR(ret);
 93 }
 94 
 95 struct regmap *syscon_node_to_regmap(struct device_node *np)
 96 {
 97         struct syscon *entry, *syscon = NULL;
 98 
 99         spin_lock(&syscon_list_slock);
100 
101         list_for_each_entry(entry, &syscon_list, list)
102                 if (entry->np == np) {
103                         syscon = entry;
104                         break;
105                 }
106 
107         spin_unlock(&syscon_list_slock);
108 
109         if (!syscon)
110                 syscon = of_syscon_register(np);
111 
112         if (IS_ERR(syscon))
113                 return ERR_CAST(syscon);
114 
115         return syscon->regmap;
116 }
117 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
118 
119 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
120 {
121         struct device_node *syscon_np;
122         struct regmap *regmap;
123 
124         syscon_np = of_find_compatible_node(NULL, NULL, s);
125         if (!syscon_np)
126                 return ERR_PTR(-ENODEV);
127 
128         regmap = syscon_node_to_regmap(syscon_np);
129         of_node_put(syscon_np);
130 
131         return regmap;
132 }
133 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
134 
135 static int syscon_match_pdevname(struct device *dev, void *data)
136 {
137         return !strcmp(dev_name(dev), (const char *)data);
138 }
139 
140 struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
141 {
142         struct device *dev;
143         struct syscon *syscon;
144 
145         dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
146                                  syscon_match_pdevname);
147         if (!dev)
148                 return ERR_PTR(-EPROBE_DEFER);
149 
150         syscon = dev_get_drvdata(dev);
151 
152         return syscon->regmap;
153 }
154 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
155 
156 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
157                                         const char *property)
158 {
159         struct device_node *syscon_np;
160         struct regmap *regmap;
161 
162         if (property)
163                 syscon_np = of_parse_phandle(np, property, 0);
164         else
165                 syscon_np = np;
166 
167         if (!syscon_np)
168                 return ERR_PTR(-ENODEV);
169 
170         regmap = syscon_node_to_regmap(syscon_np);
171         of_node_put(syscon_np);
172 
173         return regmap;
174 }
175 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
176 
177 static int syscon_probe(struct platform_device *pdev)
178 {
179         struct device *dev = &pdev->dev;
180         struct syscon_platform_data *pdata = dev_get_platdata(dev);
181         struct syscon *syscon;
182         struct resource *res;
183         void __iomem *base;
184 
185         syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
186         if (!syscon)
187                 return -ENOMEM;
188 
189         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
190         if (!res)
191                 return -ENOENT;
192 
193         base = devm_ioremap(dev, res->start, resource_size(res));
194         if (!base)
195                 return -ENOMEM;
196 
197         syscon_regmap_config.max_register = res->end - res->start - 3;
198         if (pdata)
199                 syscon_regmap_config.name = pdata->label;
200         syscon->regmap = devm_regmap_init_mmio(dev, base,
201                                         &syscon_regmap_config);
202         if (IS_ERR(syscon->regmap)) {
203                 dev_err(dev, "regmap init failed\n");
204                 return PTR_ERR(syscon->regmap);
205         }
206 
207         platform_set_drvdata(pdev, syscon);
208 
209         dev_dbg(dev, "regmap %pR registered\n", res);
210 
211         return 0;
212 }
213 
214 static const struct platform_device_id syscon_ids[] = {
215         { "syscon", },
216         { }
217 };
218 
219 static struct platform_driver syscon_driver = {
220         .driver = {
221                 .name = "syscon",
222         },
223         .probe          = syscon_probe,
224         .id_table       = syscon_ids,
225 };
226 
227 static int __init syscon_init(void)
228 {
229         return platform_driver_register(&syscon_driver);
230 }
231 postcore_initcall(syscon_init);
232 
233 static void __exit syscon_exit(void)
234 {
235         platform_driver_unregister(&syscon_driver);
236 }
237 module_exit(syscon_exit);
238 
239 MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
240 MODULE_DESCRIPTION("System Control driver");
241 MODULE_LICENSE("GPL v2");
242 

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