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");