linux/drivers/mfd/syscon.c
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   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
  25static struct platform_driver syscon_driver;
  26
  27struct syscon {
  28        struct regmap *regmap;
  29};
  30
  31static 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
  38struct 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}
  52EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
  53
  54struct 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}
  68EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
  69
  70static int syscon_match_pdevname(struct device *dev, void *data)
  71{
  72        struct platform_device *pdev = to_platform_device(dev);
  73        const struct platform_device_id *id = platform_get_device_id(pdev);
  74
  75        if (id)
  76                if (!strcmp(id->name, (const char *)data))
  77                        return 1;
  78
  79        return !strcmp(dev_name(dev), (const char *)data);
  80}
  81
  82struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
  83{
  84        struct device *dev;
  85        struct syscon *syscon;
  86
  87        dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
  88                                 syscon_match_pdevname);
  89        if (!dev)
  90                return ERR_PTR(-EPROBE_DEFER);
  91
  92        syscon = dev_get_drvdata(dev);
  93
  94        return syscon->regmap;
  95}
  96EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
  97
  98struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
  99                                        const char *property)
 100{
 101        struct device_node *syscon_np;
 102        struct regmap *regmap;
 103
 104        syscon_np = of_parse_phandle(np, property, 0);
 105        if (!syscon_np)
 106                return ERR_PTR(-ENODEV);
 107
 108        regmap = syscon_node_to_regmap(syscon_np);
 109        of_node_put(syscon_np);
 110
 111        return regmap;
 112}
 113EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
 114
 115static const struct of_device_id of_syscon_match[] = {
 116        { .compatible = "syscon", },
 117        { },
 118};
 119
 120static struct regmap_config syscon_regmap_config = {
 121        .reg_bits = 32,
 122        .val_bits = 32,
 123        .reg_stride = 4,
 124};
 125
 126static int syscon_probe(struct platform_device *pdev)
 127{
 128        struct device *dev = &pdev->dev;
 129        struct syscon *syscon;
 130        struct resource *res;
 131        void __iomem *base;
 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        base = devm_ioremap(dev, res->start, resource_size(res));
 142        if (!base)
 143                return -ENOMEM;
 144
 145        syscon_regmap_config.max_register = res->end - res->start - 3;
 146        syscon->regmap = devm_regmap_init_mmio(dev, 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
 160static const struct platform_device_id syscon_ids[] = {
 161        { "syscon", },
 162        { }
 163};
 164
 165static 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
 175static int __init syscon_init(void)
 176{
 177        return platform_driver_register(&syscon_driver);
 178}
 179postcore_initcall(syscon_init);
 180
 181static void __exit syscon_exit(void)
 182{
 183        platform_driver_unregister(&syscon_driver);
 184}
 185module_exit(syscon_exit);
 186
 187MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
 188MODULE_DESCRIPTION("System Control driver");
 189MODULE_LICENSE("GPL v2");
 190
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