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