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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/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 #include <linux/mfd/syscon.h>
 24 
 25 static struct platform_driver syscon_driver;
 26 
 27 struct syscon {
 28         struct regmap *regmap;
 29 };
 30 
 31 static int syscon_match_node(struct device *dev, void *data)
 32 {
 33         struct device_node *dn = data;
 34 
 35         return (dev->of_node == dn) ? 1 : 0;
 36 }
 37 
 38 struct regmap *syscon_node_to_regmap(struct device_node *np)
 39 {
 40         struct syscon *syscon;
 41         struct device *dev;
 42 
 43         dev = driver_find_device(&syscon_driver.driver, NULL, np,
 44                                  syscon_match_node);
 45         if (!dev)
 46                 return ERR_PTR(-EPROBE_DEFER);
 47 
 48         syscon = dev_get_drvdata(dev);
 49 
 50         return syscon->regmap;
 51 }
 52 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
 53 
 54 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
 55 {
 56         struct device_node *syscon_np;
 57         struct regmap *regmap;
 58 
 59         syscon_np = of_find_compatible_node(NULL, NULL, s);
 60         if (!syscon_np)
 61                 return ERR_PTR(-ENODEV);
 62 
 63         regmap = syscon_node_to_regmap(syscon_np);
 64         of_node_put(syscon_np);
 65 
 66         return regmap;
 67 }
 68 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
 69 
 70 static int syscon_match_pdevname(struct device *dev, void *data)
 71 {
 72         return !strcmp(dev_name(dev), (const char *)data);
 73 }
 74 
 75 struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
 76 {
 77         struct device *dev;
 78         struct syscon *syscon;
 79 
 80         dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
 81                                  syscon_match_pdevname);
 82         if (!dev)
 83                 return ERR_PTR(-EPROBE_DEFER);
 84 
 85         syscon = dev_get_drvdata(dev);
 86 
 87         return syscon->regmap;
 88 }
 89 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
 90 
 91 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
 92                                         const char *property)
 93 {
 94         struct device_node *syscon_np;
 95         struct regmap *regmap;
 96 
 97         syscon_np = of_parse_phandle(np, property, 0);
 98         if (!syscon_np)
 99                 return ERR_PTR(-ENODEV);
100 
101         regmap = syscon_node_to_regmap(syscon_np);
102         of_node_put(syscon_np);
103 
104         return regmap;
105 }
106 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
107 
108 static const struct of_device_id of_syscon_match[] = {
109         { .compatible = "syscon", },
110         { },
111 };
112 
113 static struct regmap_config syscon_regmap_config = {
114         .reg_bits = 32,
115         .val_bits = 32,
116         .reg_stride = 4,
117 };
118 
119 static int syscon_probe(struct platform_device *pdev)
120 {
121         struct device *dev = &pdev->dev;
122         struct syscon *syscon;
123         struct resource *res;
124         void __iomem *base;
125 
126         syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
127         if (!syscon)
128                 return -ENOMEM;
129 
130         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
131         if (!res)
132                 return -ENOENT;
133 
134         base = devm_ioremap(dev, res->start, resource_size(res));
135         if (!base)
136                 return -ENOMEM;
137 
138         syscon_regmap_config.max_register = res->end - res->start - 3;
139         syscon->regmap = devm_regmap_init_mmio(dev, base,
140                                         &syscon_regmap_config);
141         if (IS_ERR(syscon->regmap)) {
142                 dev_err(dev, "regmap init failed\n");
143                 return PTR_ERR(syscon->regmap);
144         }
145 
146         platform_set_drvdata(pdev, syscon);
147 
148         dev_dbg(dev, "regmap %pR registered\n", res);
149 
150         return 0;
151 }
152 
153 static const struct platform_device_id syscon_ids[] = {
154         { "syscon", },
155         { }
156 };
157 
158 static struct platform_driver syscon_driver = {
159         .driver = {
160                 .name = "syscon",
161                 .owner = THIS_MODULE,
162                 .of_match_table = of_syscon_match,
163         },
164         .probe          = syscon_probe,
165         .id_table       = syscon_ids,
166 };
167 
168 static int __init syscon_init(void)
169 {
170         return platform_driver_register(&syscon_driver);
171 }
172 postcore_initcall(syscon_init);
173 
174 static void __exit syscon_exit(void)
175 {
176         platform_driver_unregister(&syscon_driver);
177 }
178 module_exit(syscon_exit);
179 
180 MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
181 MODULE_DESCRIPTION("System Control driver");
182 MODULE_LICENSE("GPL v2");
183 

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