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");