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/hwspinlock.h>
  17 #include <linux/io.h>
  18 #include <linux/module.h>
  19 #include <linux/list.h>
  20 #include <linux/of.h>
  21 #include <linux/of_address.h>
  22 #include <linux/of_platform.h>
  23 #include <linux/platform_data/syscon.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/regmap.h>
  26 #include <linux/mfd/syscon.h>
  27 #include <linux/slab.h>
  28
  29 static struct platform_driver syscon_driver;
  30
  31 static DEFINE_SPINLOCK(syscon_list_slock);
  32 static LIST_HEAD(syscon_list);
  33
  34 struct syscon {
  35         struct device_node *np;
  36         struct regmap *regmap;
  37         struct list_head list;
  38 };
  39
  40 static const struct regmap_config syscon_regmap_config = {
  41         .reg_bits = 32,
  42         .val_bits = 32,
  43         .reg_stride = 4,
  44 };
  45
  46 static struct syscon *of_syscon_register(struct device_node *np)
  47 {
  48         struct syscon *syscon;
  49         struct regmap *regmap;
  50         void __iomem *base;
  51         u32 reg_io_width;
  52         int ret;
  53         struct regmap_config syscon_config = syscon_regmap_config;
  54         struct resource res;
  55
  56         if (!of_device_is_compatible(np, "syscon"))
  57                 return ERR_PTR(-EINVAL);
  58
  59         syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
  60         if (!syscon)
  61                 return ERR_PTR(-ENOMEM);
  62
  63         if (of_address_to_resource(np, 0, &res)) {
  64                 ret = -ENOMEM;
  65                 goto err_map;
  66         }
  67
  68         base = ioremap(res.start, resource_size(&res));
  69         if (!base) {
  70                 ret = -ENOMEM;
  71                 goto err_map;
  72         }
  73
  74         /* Parse the device's DT node for an endianness specification */
  75         if (of_property_read_bool(np, "big-endian"))
  76                 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
  77         else if (of_property_read_bool(np, "little-endian"))
  78                 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
  79         else if (of_property_read_bool(np, "native-endian"))
  80                 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
  81
  82         /*
  83          * search for reg-io-width property in DT. If it is not provided,
  84          * default to 4 bytes. regmap_init_mmio will return an error if values
  85          * are invalid so there is no need to check them here.
  86          */
  87         ret = of_property_read_u32(np, "reg-io-width", &reg_io_width);
  88         if (ret)
  89                 reg_io_width = 4;
  90
  91         ret = of_hwspin_lock_get_id(np, 0);
  92         if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
  93                 syscon_config.use_hwlock = true;
  94                 syscon_config.hwlock_id = ret;
  95                 syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
  96         } else if (ret < 0) {
  97                 switch (ret) {
  98                 case -ENOENT:
  99                         /* Ignore missing hwlock, it's optional. */
 100                         break;
 101                 default:
 102                         pr_err("Failed to retrieve valid hwlock: %d\n", ret);
 103                         /* fall-through */
 104                 case -EPROBE_DEFER:
 105                         goto err_regmap;
 106                 }
 107         }
 108
 109         syscon_config.reg_stride = reg_io_width;
 110         syscon_config.val_bits = reg_io_width * 8;
 111         syscon_config.max_register = resource_size(&res) - reg_io_width;
 112
 113         regmap = regmap_init_mmio(NULL, base, &syscon_config);
 114         if (IS_ERR(regmap)) {
 115                 pr_err("regmap init failed\n");
 116                 ret = PTR_ERR(regmap);
 117                 goto err_regmap;
 118         }
 119
 120         syscon->regmap = regmap;
 121         syscon->np = np;
 122
 123         spin_lock(&syscon_list_slock);
 124         list_add_tail(&syscon->list, &syscon_list);
 125         spin_unlock(&syscon_list_slock);
 126
 127         return syscon;
 128
 129 err_regmap:
 130         iounmap(base);
 131 err_map:
 132         kfree(syscon);
 133         return ERR_PTR(ret);
 134 }
 135
 136 struct regmap *syscon_node_to_regmap(struct device_node *np)
 137 {
 138         struct syscon *entry, *syscon = NULL;
 139
 140         spin_lock(&syscon_list_slock);
 141
 142         list_for_each_entry(entry, &syscon_list, list)
 143                 if (entry->np == np) {
 144                         syscon = entry;
 145                         break;
 146                 }
 147
 148         spin_unlock(&syscon_list_slock);
 149
 150         if (!syscon)
 151                 syscon = of_syscon_register(np);
 152
 153         if (IS_ERR(syscon))
 154                 return ERR_CAST(syscon);
 155
 156         return syscon->regmap;
 157 }
 158 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
 159
 160 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
 161 {
 162         struct device_node *syscon_np;
 163         struct regmap *regmap;
 164
 165         syscon_np = of_find_compatible_node(NULL, NULL, s);
 166         if (!syscon_np)
 167                 return ERR_PTR(-ENODEV);
 168
 169         regmap = syscon_node_to_regmap(syscon_np);
 170         of_node_put(syscon_np);
 171
 172         return regmap;
 173 }
 174 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
 175
 176 static int syscon_match_pdevname(struct device *dev, void *data)
 177 {
 178         return !strcmp(dev_name(dev), (const char *)data);
 179 }
 180
 181 struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
 182 {
 183         struct device *dev;
 184         struct syscon *syscon;
 185
 186         dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
 187                                  syscon_match_pdevname);
 188         if (!dev)
 189                 return ERR_PTR(-EPROBE_DEFER);
 190
 191         syscon = dev_get_drvdata(dev);
 192
 193         return syscon->regmap;
 194 }
 195 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
 196
 197 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
 198                                         const char *property)
 199 {
 200         struct device_node *syscon_np;
 201         struct regmap *regmap;
 202
 203         if (property)
 204                 syscon_np = of_parse_phandle(np, property, 0);
 205         else
 206                 syscon_np = np;
 207
 208         if (!syscon_np)
 209                 return ERR_PTR(-ENODEV);
 210
 211         regmap = syscon_node_to_regmap(syscon_np);
 212         of_node_put(syscon_np);
 213
 214         return regmap;
 215 }
 216 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
 217
 218 static int syscon_probe(struct platform_device *pdev)
 219 {
 220         struct device *dev = &pdev->dev;
 221         struct syscon_platform_data *pdata = dev_get_platdata(dev);
 222         struct syscon *syscon;
 223         struct regmap_config syscon_config = syscon_regmap_config;
 224         struct resource *res;
 225         void __iomem *base;
 226
 227         syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
 228         if (!syscon)
 229                 return -ENOMEM;
 230
 231         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 232         if (!res)
 233                 return -ENOENT;
 234
 235         base = devm_ioremap(dev, res->start, resource_size(res));
 236         if (!base)
 237                 return -ENOMEM;
 238
 239         syscon_config.max_register = res->end - res->start - 3;
 240         if (pdata)
 241                 syscon_config.name = pdata->label;
 242         syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
 243         if (IS_ERR(syscon->regmap)) {
 244                 dev_err(dev, "regmap init failed\n");
 245                 return PTR_ERR(syscon->regmap);
 246         }
 247
 248         platform_set_drvdata(pdev, syscon);
 249
 250         dev_dbg(dev, "regmap %pR registered\n", res);
 251
 252         return 0;
 253 }
 254
 255 static const struct platform_device_id syscon_ids[] = {
 256         { "syscon", },
 257         { }
 258 };
 259
 260 static struct platform_driver syscon_driver = {
 261         .driver = {
 262                 .name = "syscon",
 263         },
 264         .probe          = syscon_probe,
 265         .id_table       = syscon_ids,
 266 };
 267
 268 static int __init syscon_init(void)
 269 {
 270         return platform_driver_register(&syscon_driver);
 271 }
 272 postcore_initcall(syscon_init);
 273
 274 static void __exit syscon_exit(void)
 275 {
 276         platform_driver_unregister(&syscon_driver);
 277 }
 278 module_exit(syscon_exit);
 279
 280 MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
 281 MODULE_DESCRIPTION("System Control driver");
 282 MODULE_LICENSE("GPL v2");