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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_data/syscon.h>
 22 #include <linux/platform_device.h>
 23 #include <linux/regmap.h>
 24 #include <linux/mfd/syscon.h>
 25 
 26 static struct platform_driver syscon_driver;
 27 
 28 struct syscon {
 29         struct regmap *regmap;
 30 };
 31 
 32 static int syscon_match_node(struct device *dev, void *data)
 33 {
 34         struct device_node *dn = data;
 35 
 36         return (dev->of_node == dn) ? 1 : 0;
 37 }
 38 
 39 struct regmap *syscon_node_to_regmap(struct device_node *np)
 40 {
 41         struct syscon *syscon;
 42         struct device *dev;
 43 
 44         dev = driver_find_device(&syscon_driver.driver, NULL, np,
 45                                  syscon_match_node);
 46         if (!dev)
 47                 return ERR_PTR(-EPROBE_DEFER);
 48 
 49         syscon = dev_get_drvdata(dev);
 50 
 51         return syscon->regmap;
 52 }
 53 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
 54 
 55 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
 56 {
 57         struct device_node *syscon_np;
 58         struct regmap *regmap;
 59 
 60         syscon_np = of_find_compatible_node(NULL, NULL, s);
 61         if (!syscon_np)
 62                 return ERR_PTR(-ENODEV);
 63 
 64         regmap = syscon_node_to_regmap(syscon_np);
 65         of_node_put(syscon_np);
 66 
 67         return regmap;
 68 }
 69 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
 70 
 71 static int syscon_match_pdevname(struct device *dev, void *data)
 72 {
 73         return !strcmp(dev_name(dev), (const char *)data);
 74 }
 75 
 76 struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
 77 {
 78         struct device *dev;
 79         struct syscon *syscon;
 80 
 81         dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
 82                                  syscon_match_pdevname);
 83         if (!dev)
 84                 return ERR_PTR(-EPROBE_DEFER);
 85 
 86         syscon = dev_get_drvdata(dev);
 87 
 88         return syscon->regmap;
 89 }
 90 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
 91 
 92 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
 93                                         const char *property)
 94 {
 95         struct device_node *syscon_np;
 96         struct regmap *regmap;
 97 
 98         if (property)
 99                 syscon_np = of_parse_phandle(np, property, 0);
100         else
101                 syscon_np = np;
102 
103         if (!syscon_np)
104                 return ERR_PTR(-ENODEV);
105 
106         regmap = syscon_node_to_regmap(syscon_np);
107         of_node_put(syscon_np);
108 
109         return regmap;
110 }
111 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
112 
113 static const struct of_device_id of_syscon_match[] = {
114         { .compatible = "syscon", },
115         { },
116 };
117 
118 static struct regmap_config syscon_regmap_config = {
119         .reg_bits = 32,
120         .val_bits = 32,
121         .reg_stride = 4,
122 };
123 
124 static int syscon_probe(struct platform_device *pdev)
125 {
126         struct device *dev = &pdev->dev;
127         struct syscon_platform_data *pdata = dev_get_platdata(dev);
128         struct syscon *syscon;
129         struct resource *res;
130         void __iomem *base;
131 
132         syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
133         if (!syscon)
134                 return -ENOMEM;
135 
136         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
137         if (!res)
138                 return -ENOENT;
139 
140         base = devm_ioremap(dev, res->start, resource_size(res));
141         if (!base)
142                 return -ENOMEM;
143 
144         syscon_regmap_config.max_register = res->end - res->start - 3;
145         if (pdata)
146                 syscon_regmap_config.name = pdata->label;
147         syscon->regmap = devm_regmap_init_mmio(dev, base,
148                                         &syscon_regmap_config);
149         if (IS_ERR(syscon->regmap)) {
150                 dev_err(dev, "regmap init failed\n");
151                 return PTR_ERR(syscon->regmap);
152         }
153 
154         platform_set_drvdata(pdev, syscon);
155 
156         dev_dbg(dev, "regmap %pR registered\n", res);
157 
158         return 0;
159 }
160 
161 static const struct platform_device_id syscon_ids[] = {
162         { "syscon", },
163         { }
164 };
165 
166 static struct platform_driver syscon_driver = {
167         .driver = {
168                 .name = "syscon",
169                 .owner = THIS_MODULE,
170                 .of_match_table = of_syscon_match,
171         },
172         .probe          = syscon_probe,
173         .id_table       = syscon_ids,
174 };
175 
176 static int __init syscon_init(void)
177 {
178         return platform_driver_register(&syscon_driver);
179 }
180 postcore_initcall(syscon_init);
181 
182 static void __exit syscon_exit(void)
183 {
184         platform_driver_unregister(&syscon_driver);
185 }
186 module_exit(syscon_exit);
187 
188 MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
189 MODULE_DESCRIPTION("System Control driver");
190 MODULE_LICENSE("GPL v2");
191 

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