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/list.h>
  19 #include <linux/of.h>
  20 #include <linux/of_address.h>
  21 #include <linux/of_platform.h>
  22 #include <linux/platform_data/syscon.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/regmap.h>
  25 #include <linux/mfd/syscon.h>
  26 #include <linux/slab.h>
  27
  28 static struct platform_driver syscon_driver;
  29
  30 static DEFINE_SPINLOCK(syscon_list_slock);
  31 static LIST_HEAD(syscon_list);
  32
  33 struct syscon {
  34         struct device_node *np;
  35         struct regmap *regmap;
  36         struct list_head list;
  37 };
  38
  39 static struct regmap_config syscon_regmap_config = {
  40         .reg_bits = 32,
  41         .val_bits = 32,
  42         .reg_stride = 4,
  43 };
  44
  45 static struct syscon *of_syscon_register(struct device_node *np)
  46 {
  47         struct syscon *syscon;
  48         struct regmap *regmap;
  49         void __iomem *base;
  50         int ret;
  51         struct regmap_config syscon_config = syscon_regmap_config;
  52
  53         if (!of_device_is_compatible(np, "syscon"))
  54                 return ERR_PTR(-EINVAL);
  55
  56         syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
  57         if (!syscon)
  58                 return ERR_PTR(-ENOMEM);
  59
  60         base = of_iomap(np, 0);
  61         if (!base) {
  62                 ret = -ENOMEM;
  63                 goto err_map;
  64         }
  65
  66         /* Parse the device's DT node for an endianness specification */
  67         if (of_property_read_bool(np, "big-endian"))
  68                 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
  69          else if (of_property_read_bool(np, "little-endian"))
  70                 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
  71
  72         regmap = regmap_init_mmio(NULL, base, &syscon_config);
  73         if (IS_ERR(regmap)) {
  74                 pr_err("regmap init failed\n");
  75                 ret = PTR_ERR(regmap);
  76                 goto err_regmap;
  77         }
  78
  79         syscon->regmap = regmap;
  80         syscon->np = np;
  81
  82         spin_lock(&syscon_list_slock);
  83         list_add_tail(&syscon->list, &syscon_list);
  84         spin_unlock(&syscon_list_slock);
  85
  86         return syscon;
  87
  88 err_regmap:
  89         iounmap(base);
  90 err_map:
  91         kfree(syscon);
  92         return ERR_PTR(ret);
  93 }
  94
  95 struct regmap *syscon_node_to_regmap(struct device_node *np)
  96 {
  97         struct syscon *entry, *syscon = NULL;
  98
  99         spin_lock(&syscon_list_slock);
 100
 101         list_for_each_entry(entry, &syscon_list, list)
 102                 if (entry->np == np) {
 103                         syscon = entry;
 104                         break;
 105                 }
 106
 107         spin_unlock(&syscon_list_slock);
 108
 109         if (!syscon)
 110                 syscon = of_syscon_register(np);
 111
 112         if (IS_ERR(syscon))
 113                 return ERR_CAST(syscon);
 114
 115         return syscon->regmap;
 116 }
 117 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
 118
 119 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
 120 {
 121         struct device_node *syscon_np;
 122         struct regmap *regmap;
 123
 124         syscon_np = of_find_compatible_node(NULL, NULL, s);
 125         if (!syscon_np)
 126                 return ERR_PTR(-ENODEV);
 127
 128         regmap = syscon_node_to_regmap(syscon_np);
 129         of_node_put(syscon_np);
 130
 131         return regmap;
 132 }
 133 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
 134
 135 static int syscon_match_pdevname(struct device *dev, void *data)
 136 {
 137         return !strcmp(dev_name(dev), (const char *)data);
 138 }
 139
 140 struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
 141 {
 142         struct device *dev;
 143         struct syscon *syscon;
 144
 145         dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
 146                                  syscon_match_pdevname);
 147         if (!dev)
 148                 return ERR_PTR(-EPROBE_DEFER);
 149
 150         syscon = dev_get_drvdata(dev);
 151
 152         return syscon->regmap;
 153 }
 154 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
 155
 156 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
 157                                         const char *property)
 158 {
 159         struct device_node *syscon_np;
 160         struct regmap *regmap;
 161
 162         if (property)
 163                 syscon_np = of_parse_phandle(np, property, 0);
 164         else
 165                 syscon_np = np;
 166
 167         if (!syscon_np)
 168                 return ERR_PTR(-ENODEV);
 169
 170         regmap = syscon_node_to_regmap(syscon_np);
 171         of_node_put(syscon_np);
 172
 173         return regmap;
 174 }
 175 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
 176
 177 static int syscon_probe(struct platform_device *pdev)
 178 {
 179         struct device *dev = &pdev->dev;
 180         struct syscon_platform_data *pdata = dev_get_platdata(dev);
 181         struct syscon *syscon;
 182         struct resource *res;
 183         void __iomem *base;
 184
 185         syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
 186         if (!syscon)
 187                 return -ENOMEM;
 188
 189         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 190         if (!res)
 191                 return -ENOENT;
 192
 193         base = devm_ioremap(dev, res->start, resource_size(res));
 194         if (!base)
 195                 return -ENOMEM;
 196
 197         syscon_regmap_config.max_register = res->end - res->start - 3;
 198         if (pdata)
 199                 syscon_regmap_config.name = pdata->label;
 200         syscon->regmap = devm_regmap_init_mmio(dev, base,
 201                                         &syscon_regmap_config);
 202         if (IS_ERR(syscon->regmap)) {
 203                 dev_err(dev, "regmap init failed\n");
 204                 return PTR_ERR(syscon->regmap);
 205         }
 206
 207         platform_set_drvdata(pdev, syscon);
 208
 209         dev_dbg(dev, "regmap %pR registered\n", res);
 210
 211         return 0;
 212 }
 213
 214 static const struct platform_device_id syscon_ids[] = {
 215         { "syscon", },
 216         { }
 217 };
 218
 219 static struct platform_driver syscon_driver = {
 220         .driver = {
 221                 .name = "syscon",
 222         },
 223         .probe          = syscon_probe,
 224         .id_table       = syscon_ids,
 225 };
 226
 227 static int __init syscon_init(void)
 228 {
 229         return platform_driver_register(&syscon_driver);
 230 }
 231 postcore_initcall(syscon_init);
 232
 233 static void __exit syscon_exit(void)
 234 {
 235         platform_driver_unregister(&syscon_driver);
 236 }
 237 module_exit(syscon_exit);
 238
 239 MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
 240 MODULE_DESCRIPTION("System Control driver");
 241 MODULE_LICENSE("GPL v2");