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.name = of_node_full_name(np);
 110         syscon_config.reg_stride = reg_io_width;
 111         syscon_config.val_bits = reg_io_width * 8;
 112         syscon_config.max_register = resource_size(&res) - reg_io_width;
 113         syscon_config.name = of_node_full_name(np);
 114
 115         regmap = regmap_init_mmio(NULL, base, &syscon_config);
 116         if (IS_ERR(regmap)) {
 117                 pr_err("regmap init failed\n");
 118                 ret = PTR_ERR(regmap);
 119                 goto err_regmap;
 120         }
 121
 122         syscon->regmap = regmap;
 123         syscon->np = np;
 124
 125         spin_lock(&syscon_list_slock);
 126         list_add_tail(&syscon->list, &syscon_list);
 127         spin_unlock(&syscon_list_slock);
 128
 129         return syscon;
 130
 131 err_regmap:
 132         iounmap(base);
 133 err_map:
 134         kfree(syscon);
 135         return ERR_PTR(ret);
 136 }
 137
 138 struct regmap *syscon_node_to_regmap(struct device_node *np)
 139 {
 140         struct syscon *entry, *syscon = NULL;
 141
 142         spin_lock(&syscon_list_slock);
 143
 144         list_for_each_entry(entry, &syscon_list, list)
 145                 if (entry->np == np) {
 146                         syscon = entry;
 147                         break;
 148                 }
 149
 150         spin_unlock(&syscon_list_slock);
 151
 152         if (!syscon)
 153                 syscon = of_syscon_register(np);
 154
 155         if (IS_ERR(syscon))
 156                 return ERR_CAST(syscon);
 157
 158         return syscon->regmap;
 159 }
 160 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
 161
 162 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
 163 {
 164         struct device_node *syscon_np;
 165         struct regmap *regmap;
 166
 167         syscon_np = of_find_compatible_node(NULL, NULL, s);
 168         if (!syscon_np)
 169                 return ERR_PTR(-ENODEV);
 170
 171         regmap = syscon_node_to_regmap(syscon_np);
 172         of_node_put(syscon_np);
 173
 174         return regmap;
 175 }
 176 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
 177
 178 static int syscon_match_pdevname(struct device *dev, void *data)
 179 {
 180         return !strcmp(dev_name(dev), (const char *)data);
 181 }
 182
 183 struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
 184 {
 185         struct device *dev;
 186         struct syscon *syscon;
 187
 188         dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
 189                                  syscon_match_pdevname);
 190         if (!dev)
 191                 return ERR_PTR(-EPROBE_DEFER);
 192
 193         syscon = dev_get_drvdata(dev);
 194
 195         return syscon->regmap;
 196 }
 197 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);
 198
 199 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
 200                                         const char *property)
 201 {
 202         struct device_node *syscon_np;
 203         struct regmap *regmap;
 204
 205         if (property)
 206                 syscon_np = of_parse_phandle(np, property, 0);
 207         else
 208                 syscon_np = np;
 209
 210         if (!syscon_np)
 211                 return ERR_PTR(-ENODEV);
 212
 213         regmap = syscon_node_to_regmap(syscon_np);
 214         of_node_put(syscon_np);
 215
 216         return regmap;
 217 }
 218 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
 219
 220 static int syscon_probe(struct platform_device *pdev)
 221 {
 222         struct device *dev = &pdev->dev;
 223         struct syscon_platform_data *pdata = dev_get_platdata(dev);
 224         struct syscon *syscon;
 225         struct regmap_config syscon_config = syscon_regmap_config;
 226         struct resource *res;
 227         void __iomem *base;
 228
 229         syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
 230         if (!syscon)
 231                 return -ENOMEM;
 232
 233         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 234         if (!res)
 235                 return -ENOENT;
 236
 237         base = devm_ioremap(dev, res->start, resource_size(res));
 238         if (!base)
 239                 return -ENOMEM;
 240
 241         syscon_config.max_register = res->end - res->start - 3;
 242         if (pdata)
 243                 syscon_config.name = pdata->label;
 244         syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
 245         if (IS_ERR(syscon->regmap)) {
 246                 dev_err(dev, "regmap init failed\n");
 247                 return PTR_ERR(syscon->regmap);
 248         }
 249
 250         platform_set_drvdata(pdev, syscon);
 251
 252         dev_dbg(dev, "regmap %pR registered\n", res);
 253
 254         return 0;
 255 }
 256
 257 static const struct platform_device_id syscon_ids[] = {
 258         { "syscon", },
 259         { }
 260 };
 261
 262 static struct platform_driver syscon_driver = {
 263         .driver = {
 264                 .name = "syscon",
 265         },
 266         .probe          = syscon_probe,
 267         .id_table       = syscon_ids,
 268 };
 269
 270 static int __init syscon_init(void)
 271 {
 272         return platform_driver_register(&syscon_driver);
 273 }
 274 postcore_initcall(syscon_init);
 275
 276 static void __exit syscon_exit(void)
 277 {
 278         platform_driver_unregister(&syscon_driver);
 279 }
 280 module_exit(syscon_exit);
 281
 282 MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
 283 MODULE_DESCRIPTION("System Control driver");
 284 MODULE_LICENSE("GPL v2");