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         void __iomem *base;
  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         struct platform_device *pdev = to_platform_device(dev);
  74         const struct platform_device_id *id = platform_get_device_id(pdev);
  75
  76         if (id)
  77                 if (!strcmp(id->name, (const char *)data))
  78                         return 1;
  79
  80         return !strcmp(dev_name(dev), (const char *)data);
  81 }
  82
  83 struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
  84 {
  85         struct device *dev;
  86         struct syscon *syscon;
  87
  88         dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
  89                                  syscon_match_pdevname);
  90         if (!dev)
  91                 return ERR_PTR(-EPROBE_DEFER);
  92
  93         syscon = dev_get_drvdata(dev);
  94
  95         return syscon->regmap;
  96 }
  97 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
  98
  99 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
 100                                         const char *property)
 101 {
 102         struct device_node *syscon_np;
 103         struct regmap *regmap;
 104
 105         syscon_np = of_parse_phandle(np, property, 0);
 106         if (!syscon_np)
 107                 return ERR_PTR(-ENODEV);
 108
 109         regmap = syscon_node_to_regmap(syscon_np);
 110         of_node_put(syscon_np);
 111
 112         return regmap;
 113 }
 114 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
 115
 116 static const struct of_device_id of_syscon_match[] = {
 117         { .compatible = "syscon", },
 118         { },
 119 };
 120
 121 static struct regmap_config syscon_regmap_config = {
 122         .reg_bits = 32,
 123         .val_bits = 32,
 124         .reg_stride = 4,
 125 };
 126
 127 static int syscon_probe(struct platform_device *pdev)
 128 {
 129         struct device *dev = &pdev->dev;
 130         struct syscon *syscon;
 131         struct resource *res;
 132
 133         syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
 134         if (!syscon)
 135                 return -ENOMEM;
 136
 137         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 138         if (!res)
 139                 return -ENOENT;
 140
 141         syscon->base = devm_ioremap(dev, res->start, resource_size(res));
 142         if (!syscon->base)
 143                 return -ENOMEM;
 144
 145         syscon_regmap_config.max_register = res->end - res->start - 3;
 146         syscon->regmap = devm_regmap_init_mmio(dev, syscon->base,
 147                                         &syscon_regmap_config);
 148         if (IS_ERR(syscon->regmap)) {
 149                 dev_err(dev, "regmap init failed\n");
 150                 return PTR_ERR(syscon->regmap);
 151         }
 152
 153         platform_set_drvdata(pdev, syscon);
 154
 155         dev_info(dev, "regmap %pR registered\n", res);
 156
 157         return 0;
 158 }
 159
 160 static const struct platform_device_id syscon_ids[] = {
 161         { "syscon", },
 162         { }
 163 };
 164
 165 static struct platform_driver syscon_driver = {
 166         .driver = {
 167                 .name = "syscon",
 168                 .owner = THIS_MODULE,
 169                 .of_match_table = of_syscon_match,
 170         },
 171         .probe          = syscon_probe,
 172         .id_table       = syscon_ids,
 173 };
 174
 175 static int __init syscon_init(void)
 176 {
 177         return platform_driver_register(&syscon_driver);
 178 }
 179 postcore_initcall(syscon_init);
 180
 181 static void __exit syscon_exit(void)
 182 {
 183         platform_driver_unregister(&syscon_driver);
 184 }
 185 module_exit(syscon_exit);
 186
 187 MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
 188 MODULE_DESCRIPTION("System Control driver");
 189 MODULE_LICENSE("GPL v2");