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