drivers/mfd/syscon.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * System Control Driver
   4  *
   5  * Copyright (C) 2012 Freescale Semiconductor, Inc.
   6  * Copyright (C) 2012 Linaro Ltd.
   7  *
   8  * Author: Dong Aisheng <dong.aisheng@linaro.org>
   9  */
  10
  11 #include <linux/clk.h>
  12 #include <linux/err.h>
  13 #include <linux/hwspinlock.h>
  14 #include <linux/io.h>
  15 #include <linux/init.h>
  16 #include <linux/list.h>
  17 #include <linux/of.h>
  18 #include <linux/of_address.h>
  19 #include <linux/of_platform.h>
  20 #include <linux/platform_data/syscon.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/regmap.h>
  23 #include <linux/mfd/syscon.h>
  24 #include <linux/slab.h>
  25
  26 static struct platform_driver syscon_driver;
  27
  28 static DEFINE_SPINLOCK(syscon_list_slock);
  29 static LIST_HEAD(syscon_list);
  30
  31 struct syscon {
  32         struct device_node *np;
  33         struct regmap *regmap;
  34         struct list_head list;
  35 };
  36
  37 static const struct regmap_config syscon_regmap_config = {
  38         .reg_bits = 32,
  39         .val_bits = 32,
  40         .reg_stride = 4,
  41 };
  42
  43 static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
  44 {
  45         struct clk *clk;
  46         struct syscon *syscon;
  47         struct regmap *regmap;
  48         void __iomem *base;
  49         u32 reg_io_width;
  50         int ret;
  51         struct regmap_config syscon_config = syscon_regmap_config;
  52         struct resource res;
  53
  54         syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
  55         if (!syscon)
  56                 return ERR_PTR(-ENOMEM);
  57
  58         if (of_address_to_resource(np, 0, &res)) {
  59                 ret = -ENOMEM;
  60                 goto err_map;
  61         }
  62
  63         base = ioremap(res.start, resource_size(&res));
  64         if (!base) {
  65                 ret = -ENOMEM;
  66                 goto err_map;
  67         }
  68
  69         /* Parse the device's DT node for an endianness specification */
  70         if (of_property_read_bool(np, "big-endian"))
  71                 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
  72         else if (of_property_read_bool(np, "little-endian"))
  73                 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
  74         else if (of_property_read_bool(np, "native-endian"))
  75                 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
  76
  77         /*
  78          * search for reg-io-width property in DT. If it is not provided,
  79          * default to 4 bytes. regmap_init_mmio will return an error if values
  80          * are invalid so there is no need to check them here.
  81          */
  82         ret = of_property_read_u32(np, "reg-io-width", &reg_io_width);
  83         if (ret)
  84                 reg_io_width = 4;
  85
  86         ret = of_hwspin_lock_get_id(np, 0);
  87         if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
  88                 syscon_config.use_hwlock = true;
  89                 syscon_config.hwlock_id = ret;
  90                 syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
  91         } else if (ret < 0) {
  92                 switch (ret) {
  93                 case -ENOENT:
  94                         /* Ignore missing hwlock, it's optional. */
  95                         break;
  96                 default:
  97                         pr_err("Failed to retrieve valid hwlock: %d\n", ret);
  98                         fallthrough;
  99                 case -EPROBE_DEFER:
 100                         goto err_regmap;
 101                 }
 102         }
 103
 104         syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%llx", np,
 105                                        (u64)res.start);
 106         syscon_config.reg_stride = reg_io_width;
 107         syscon_config.val_bits = reg_io_width * 8;
 108         syscon_config.max_register = resource_size(&res) - reg_io_width;
 109
 110         regmap = regmap_init_mmio(NULL, base, &syscon_config);
 111         if (IS_ERR(regmap)) {
 112                 pr_err("regmap init failed\n");
 113                 ret = PTR_ERR(regmap);
 114                 goto err_regmap;
 115         }
 116
 117         if (check_clk) {
 118                 clk = of_clk_get(np, 0);
 119                 if (IS_ERR(clk)) {
 120                         ret = PTR_ERR(clk);
 121                         /* clock is optional */
 122                         if (ret != -ENOENT)
 123                                 goto err_clk;
 124                 } else {
 125                         ret = regmap_mmio_attach_clk(regmap, clk);
 126                         if (ret)
 127                                 goto err_attach;
 128                 }
 129         }
 130
 131         syscon->regmap = regmap;
 132         syscon->np = np;
 133
 134         spin_lock(&syscon_list_slock);
 135         list_add_tail(&syscon->list, &syscon_list);
 136         spin_unlock(&syscon_list_slock);
 137
 138         return syscon;
 139
 140 err_attach:
 141         if (!IS_ERR(clk))
 142                 clk_put(clk);
 143 err_clk:
 144         regmap_exit(regmap);
 145 err_regmap:
 146         iounmap(base);
 147         kfree(syscon_config.name);
 148 err_map:
 149         kfree(syscon);
 150         return ERR_PTR(ret);
 151 }
 152
 153 static struct regmap *device_node_get_regmap(struct device_node *np,
 154                                              bool check_clk)
 155 {
 156         struct syscon *entry, *syscon = NULL;
 157
 158         spin_lock(&syscon_list_slock);
 159
 160         list_for_each_entry(entry, &syscon_list, list)
 161                 if (entry->np == np) {
 162                         syscon = entry;
 163                         break;
 164                 }
 165
 166         spin_unlock(&syscon_list_slock);
 167
 168         if (!syscon)
 169                 syscon = of_syscon_register(np, check_clk);
 170
 171         if (IS_ERR(syscon))
 172                 return ERR_CAST(syscon);
 173
 174         return syscon->regmap;
 175 }
 176
 177 struct regmap *device_node_to_regmap(struct device_node *np)
 178 {
 179         return device_node_get_regmap(np, false);
 180 }
 181 EXPORT_SYMBOL_GPL(device_node_to_regmap);
 182
 183 struct regmap *syscon_node_to_regmap(struct device_node *np)
 184 {
 185         if (!of_device_is_compatible(np, "syscon"))
 186                 return ERR_PTR(-EINVAL);
 187
 188         return device_node_get_regmap(np, true);
 189 }
 190 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
 191
 192 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
 193 {
 194         struct device_node *syscon_np;
 195         struct regmap *regmap;
 196
 197         syscon_np = of_find_compatible_node(NULL, NULL, s);
 198         if (!syscon_np)
 199                 return ERR_PTR(-ENODEV);
 200
 201         regmap = syscon_node_to_regmap(syscon_np);
 202         of_node_put(syscon_np);
 203
 204         return regmap;
 205 }
 206 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
 207
 208 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
 209                                         const char *property)
 210 {
 211         struct device_node *syscon_np;
 212         struct regmap *regmap;
 213
 214         if (property)
 215                 syscon_np = of_parse_phandle(np, property, 0);
 216         else
 217                 syscon_np = np;
 218
 219         if (!syscon_np)
 220                 return ERR_PTR(-ENODEV);
 221
 222         regmap = syscon_node_to_regmap(syscon_np);
 223         of_node_put(syscon_np);
 224
 225         return regmap;
 226 }
 227 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
 228
 229 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
 230                                         const char *property,
 231                                         int arg_count,
 232                                         unsigned int *out_args)
 233 {
 234         struct device_node *syscon_np;
 235         struct of_phandle_args args;
 236         struct regmap *regmap;
 237         unsigned int index;
 238         int rc;
 239
 240         rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
 241                         0, &args);
 242         if (rc)
 243                 return ERR_PTR(rc);
 244
 245         syscon_np = args.np;
 246         if (!syscon_np)
 247                 return ERR_PTR(-ENODEV);
 248
 249         regmap = syscon_node_to_regmap(syscon_np);
 250         for (index = 0; index < arg_count; index++)
 251                 out_args[index] = args.args[index];
 252         of_node_put(syscon_np);
 253
 254         return regmap;
 255 }
 256 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);
 257
 258 /*
 259  * It behaves the same as syscon_regmap_lookup_by_phandle() except where
 260  * there is no regmap phandle. In this case, instead of returning -ENODEV,
 261  * the function returns NULL.
 262  */
 263 struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,
 264                                         const char *property)
 265 {
 266         struct regmap *regmap;
 267
 268         regmap = syscon_regmap_lookup_by_phandle(np, property);
 269         if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
 270                 return NULL;
 271
 272         return regmap;
 273 }
 274 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);
 275
 276 static int syscon_probe(struct platform_device *pdev)
 277 {
 278         struct device *dev = &pdev->dev;
 279         struct syscon_platform_data *pdata = dev_get_platdata(dev);
 280         struct syscon *syscon;
 281         struct regmap_config syscon_config = syscon_regmap_config;
 282         struct resource *res;
 283         void __iomem *base;
 284
 285         syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
 286         if (!syscon)
 287                 return -ENOMEM;
 288
 289         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 290         if (!res)
 291                 return -ENOENT;
 292
 293         base = devm_ioremap(dev, res->start, resource_size(res));
 294         if (!base)
 295                 return -ENOMEM;
 296
 297         syscon_config.max_register = resource_size(res) - 4;
 298         if (pdata)
 299                 syscon_config.name = pdata->label;
 300         syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
 301         if (IS_ERR(syscon->regmap)) {
 302                 dev_err(dev, "regmap init failed\n");
 303                 return PTR_ERR(syscon->regmap);
 304         }
 305
 306         platform_set_drvdata(pdev, syscon);
 307
 308         dev_dbg(dev, "regmap %pR registered\n", res);
 309
 310         return 0;
 311 }
 312
 313 static const struct platform_device_id syscon_ids[] = {
 314         { "syscon", },
 315         { }
 316 };
 317
 318 static struct platform_driver syscon_driver = {
 319         .driver = {
 320                 .name = "syscon",
 321         },
 322         .probe          = syscon_probe,
 323         .id_table       = syscon_ids,
 324 };
 325
 326 static int __init syscon_init(void)
 327 {
 328         return platform_driver_register(&syscon_driver);
 329 }
 330 postcore_initcall(syscon_init);