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        void __iomem *base;
  29        struct regmap *regmap;
  30};
  31
  32static 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
  39struct 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}
  53EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
  54
  55struct 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}
  69EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
  70
  71static int syscon_match_pdevname(struct device *dev, void *data)
  72{
  73        struct platform_device *pdev = to_platform_device(dev);
  74        const struct platform_device_id *id = platform_get_device_id(pdev);
  75
  76        if (id)
  77                if (!strcmp(id->name, (const char *)data))
  78                        return 1;
  79
  80        return !strcmp(dev_name(dev), (const char *)data);
  81}
  82
  83struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
  84{
  85        struct device *dev;
  86        struct syscon *syscon;
  87
  88        dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
  89                                 syscon_match_pdevname);
  90        if (!dev)
  91                return ERR_PTR(-EPROBE_DEFER);
  92
  93        syscon = dev_get_drvdata(dev);
  94
  95        return syscon->regmap;
  96}
  97EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
  98
  99struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
 100                                        const char *property)
 101{
 102        struct device_node *syscon_np;
 103        struct regmap *regmap;
 104
 105        syscon_np = of_parse_phandle(np, property, 0);
 106        if (!syscon_np)
 107                return ERR_PTR(-ENODEV);
 108
 109        regmap = syscon_node_to_regmap(syscon_np);
 110        of_node_put(syscon_np);
 111
 112        return regmap;
 113}
 114EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
 115
 116static const struct of_device_id of_syscon_match[] = {
 117        { .compatible = "syscon", },
 118        { },
 119};
 120
 121static struct regmap_config syscon_regmap_config = {
 122        .reg_bits = 32,
 123        .val_bits = 32,
 124        .reg_stride = 4,
 125};
 126
 127static int syscon_probe(struct platform_device *pdev)
 128{
 129        struct device *dev = &pdev->dev;
 130        struct syscon *syscon;
 131        struct resource *res;
 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        syscon->base = devm_ioremap(dev, res->start, resource_size(res));
 142        if (!syscon->base)
 143                return -ENOMEM;
 144
 145        syscon_regmap_config.max_register = res->end - res->start - 3;
 146        syscon->regmap = devm_regmap_init_mmio(dev, syscon->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#ifdef CONFIG_ARCH_CLPS711X
 163        { "clps711x-syscon", },
 164#endif
 165        { }
 166};
 167
 168static struct platform_driver syscon_driver = {
 169        .driver = {
 170                .name = "syscon",
 171                .owner = THIS_MODULE,
 172                .of_match_table = of_syscon_match,
 173        },
 174        .probe          = syscon_probe,
 175        .id_table       = syscon_ids,
 176};
 177
 178static int __init syscon_init(void)
 179{
 180        return platform_driver_register(&syscon_driver);
 181}
 182postcore_initcall(syscon_init);
 183
 184static void __exit syscon_exit(void)
 185{
 186        platform_driver_unregister(&syscon_driver);
 187}
 188module_exit(syscon_exit);
 189
 190MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
 191MODULE_DESCRIPTION("System Control driver");
 192MODULE_LICENSE("GPL v2");
 193
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