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/cleanup.h>
  12 #include <linux/clk.h>
  13 #include <linux/err.h>
  14 #include <linux/hwspinlock.h>
  15 #include <linux/io.h>
  16 #include <linux/init.h>
  17 #include <linux/list.h>
  18 #include <linux/of.h>
  19 #include <linux/of_address.h>
  20 #include <linux/of_platform.h>
  21 #include <linux/platform_data/syscon.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/regmap.h>
  24 #include <linux/reset.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 reset_control *reset;
  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, bool check_res)
  47 {
  48         struct clk *clk;
  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         struct reset_control *reset;
  56
  57         struct syscon *syscon __free(kfree) = kzalloc(sizeof(*syscon), GFP_KERNEL);
  58         if (!syscon)
  59                 return ERR_PTR(-ENOMEM);
  60
  61         if (of_address_to_resource(np, 0, &res))
  62                 return ERR_PTR(-ENOMEM);
  63
  64         base = of_iomap(np, 0);
  65         if (!base)
  66                 return ERR_PTR(-ENOMEM);
  67
  68         /* Parse the device's DT node for an endianness specification */
  69         if (of_property_read_bool(np, "big-endian"))
  70                 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
  71         else if (of_property_read_bool(np, "little-endian"))
  72                 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
  73         else if (of_property_read_bool(np, "native-endian"))
  74                 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
  75
  76         /*
  77          * search for reg-io-width property in DT. If it is not provided,
  78          * default to 4 bytes. regmap_init_mmio will return an error if values
  79          * are invalid so there is no need to check them here.
  80          */
  81         ret = of_property_read_u32(np, "reg-io-width", &reg_io_width);
  82         if (ret)
  83                 reg_io_width = 4;
  84
  85         ret = of_hwspin_lock_get_id(np, 0);
  86         if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
  87                 syscon_config.use_hwlock = true;
  88                 syscon_config.hwlock_id = ret;
  89                 syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
  90         } else if (ret < 0) {
  91                 switch (ret) {
  92                 case -ENOENT:
  93                         /* Ignore missing hwlock, it's optional. */
  94                         break;
  95                 default:
  96                         pr_err("Failed to retrieve valid hwlock: %d\n", ret);
  97                         fallthrough;
  98                 case -EPROBE_DEFER:
  99                         goto err_regmap;
 100                 }
 101         }
 102
 103         syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start);
 104         if (!syscon_config.name) {
 105                 ret = -ENOMEM;
 106                 goto err_regmap;
 107         }
 108         syscon_config.reg_stride = reg_io_width;
 109         syscon_config.val_bits = reg_io_width * 8;
 110         syscon_config.max_register = resource_size(&res) - reg_io_width;
 111         if (!syscon_config.max_register)
 112                 syscon_config.max_register_is_0 = true;
 113
 114         regmap = regmap_init_mmio(NULL, base, &syscon_config);
 115         kfree(syscon_config.name);
 116         if (IS_ERR(regmap)) {
 117                 pr_err("regmap init failed\n");
 118                 ret = PTR_ERR(regmap);
 119                 goto err_regmap;
 120         }
 121
 122         if (check_res) {
 123                 clk = of_clk_get(np, 0);
 124                 if (IS_ERR(clk)) {
 125                         ret = PTR_ERR(clk);
 126                         /* clock is optional */
 127                         if (ret != -ENOENT)
 128                                 goto err_clk;
 129                 } else {
 130                         ret = regmap_mmio_attach_clk(regmap, clk);
 131                         if (ret)
 132                                 goto err_attach_clk;
 133                 }
 134
 135                 reset = of_reset_control_get_optional_exclusive(np, NULL);
 136                 if (IS_ERR(reset)) {
 137                         ret = PTR_ERR(reset);
 138                         goto err_attach_clk;
 139                 }
 140
 141                 ret = reset_control_deassert(reset);
 142                 if (ret)
 143                         goto err_reset;
 144         }
 145
 146         syscon->regmap = regmap;
 147         syscon->np = np;
 148
 149         spin_lock(&syscon_list_slock);
 150         list_add_tail(&syscon->list, &syscon_list);
 151         spin_unlock(&syscon_list_slock);
 152
 153         return_ptr(syscon);
 154
 155 err_reset:
 156         reset_control_put(reset);
 157 err_attach_clk:
 158         if (!IS_ERR(clk))
 159                 clk_put(clk);
 160 err_clk:
 161         regmap_exit(regmap);
 162 err_regmap:
 163         iounmap(base);
 164         return ERR_PTR(ret);
 165 }
 166
 167 static struct regmap *device_node_get_regmap(struct device_node *np,
 168                                              bool check_res)
 169 {
 170         struct syscon *entry, *syscon = NULL;
 171
 172         spin_lock(&syscon_list_slock);
 173
 174         list_for_each_entry(entry, &syscon_list, list)
 175                 if (entry->np == np) {
 176                         syscon = entry;
 177                         break;
 178                 }
 179
 180         spin_unlock(&syscon_list_slock);
 181
 182         if (!syscon)
 183                 syscon = of_syscon_register(np, check_res);
 184
 185         if (IS_ERR(syscon))
 186                 return ERR_CAST(syscon);
 187
 188         return syscon->regmap;
 189 }
 190
 191 /**
 192  * of_syscon_register_regmap() - Register regmap for specified device node
 193  * @np: Device tree node
 194  * @regmap: Pointer to regmap object
 195  *
 196  * Register an externally created regmap object with syscon for the specified
 197  * device tree node. This regmap will then be returned to client drivers using
 198  * the syscon_regmap_lookup_by_phandle() API.
 199  *
 200  * Return: 0 on success, negative error code on failure.
 201  */
 202 int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap)
 203 {
 204         struct syscon *entry, *syscon = NULL;
 205         int ret;
 206
 207         if (!np || !regmap)
 208                 return -EINVAL;
 209
 210         syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
 211         if (!syscon)
 212                 return -ENOMEM;
 213
 214         /* check if syscon entry already exists */
 215         spin_lock(&syscon_list_slock);
 216
 217         list_for_each_entry(entry, &syscon_list, list)
 218                 if (entry->np == np) {
 219                         ret = -EEXIST;
 220                         goto err_unlock;
 221                 }
 222
 223         syscon->regmap = regmap;
 224         syscon->np = np;
 225
 226         /* register the regmap in syscon list */
 227         list_add_tail(&syscon->list, &syscon_list);
 228         spin_unlock(&syscon_list_slock);
 229
 230         return 0;
 231
 232 err_unlock:
 233         spin_unlock(&syscon_list_slock);
 234         kfree(syscon);
 235         return ret;
 236 }
 237 EXPORT_SYMBOL_GPL(of_syscon_register_regmap);
 238
 239 struct regmap *device_node_to_regmap(struct device_node *np)
 240 {
 241         return device_node_get_regmap(np, false);
 242 }
 243 EXPORT_SYMBOL_GPL(device_node_to_regmap);
 244
 245 struct regmap *syscon_node_to_regmap(struct device_node *np)
 246 {
 247         if (!of_device_is_compatible(np, "syscon"))
 248                 return ERR_PTR(-EINVAL);
 249
 250         return device_node_get_regmap(np, true);
 251 }
 252 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
 253
 254 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
 255 {
 256         struct device_node *syscon_np;
 257         struct regmap *regmap;
 258
 259         syscon_np = of_find_compatible_node(NULL, NULL, s);
 260         if (!syscon_np)
 261                 return ERR_PTR(-ENODEV);
 262
 263         regmap = syscon_node_to_regmap(syscon_np);
 264         of_node_put(syscon_np);
 265
 266         return regmap;
 267 }
 268 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
 269
 270 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
 271                                         const char *property)
 272 {
 273         struct device_node *syscon_np;
 274         struct regmap *regmap;
 275
 276         if (property)
 277                 syscon_np = of_parse_phandle(np, property, 0);
 278         else
 279                 syscon_np = np;
 280
 281         if (!syscon_np)
 282                 return ERR_PTR(-ENODEV);
 283
 284         regmap = syscon_node_to_regmap(syscon_np);
 285
 286         if (property)
 287                 of_node_put(syscon_np);
 288
 289         return regmap;
 290 }
 291 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
 292
 293 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
 294                                         const char *property,
 295                                         int arg_count,
 296                                         unsigned int *out_args)
 297 {
 298         struct device_node *syscon_np;
 299         struct of_phandle_args args;
 300         struct regmap *regmap;
 301         unsigned int index;
 302         int rc;
 303
 304         rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
 305                         0, &args);
 306         if (rc)
 307                 return ERR_PTR(rc);
 308
 309         syscon_np = args.np;
 310         if (!syscon_np)
 311                 return ERR_PTR(-ENODEV);
 312
 313         regmap = syscon_node_to_regmap(syscon_np);
 314         for (index = 0; index < arg_count; index++)
 315                 out_args[index] = args.args[index];
 316         of_node_put(syscon_np);
 317
 318         return regmap;
 319 }
 320 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);
 321
 322 /*
 323  * It behaves the same as syscon_regmap_lookup_by_phandle() except where
 324  * there is no regmap phandle. In this case, instead of returning -ENODEV,
 325  * the function returns NULL.
 326  */
 327 struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,
 328                                         const char *property)
 329 {
 330         struct regmap *regmap;
 331
 332         regmap = syscon_regmap_lookup_by_phandle(np, property);
 333         if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
 334                 return NULL;
 335
 336         return regmap;
 337 }
 338 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);
 339
 340 static int syscon_probe(struct platform_device *pdev)
 341 {
 342         struct device *dev = &pdev->dev;
 343         struct syscon_platform_data *pdata = dev_get_platdata(dev);
 344         struct syscon *syscon;
 345         struct regmap_config syscon_config = syscon_regmap_config;
 346         struct resource *res;
 347         void __iomem *base;
 348
 349         syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
 350         if (!syscon)
 351                 return -ENOMEM;
 352
 353         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 354         if (!res)
 355                 return -ENOENT;
 356
 357         base = devm_ioremap(dev, res->start, resource_size(res));
 358         if (!base)
 359                 return -ENOMEM;
 360
 361         syscon_config.max_register = resource_size(res) - 4;
 362         if (!syscon_config.max_register)
 363                 syscon_config.max_register_is_0 = true;
 364
 365         if (pdata)
 366                 syscon_config.name = pdata->label;
 367         syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
 368         if (IS_ERR(syscon->regmap)) {
 369                 dev_err(dev, "regmap init failed\n");
 370                 return PTR_ERR(syscon->regmap);
 371         }
 372
 373         platform_set_drvdata(pdev, syscon);
 374
 375         dev_dbg(dev, "regmap %pR registered\n", res);
 376
 377         return 0;
 378 }
 379
 380 static const struct platform_device_id syscon_ids[] = {
 381         { "syscon", },
 382         { }
 383 };
 384
 385 static struct platform_driver syscon_driver = {
 386         .driver = {
 387                 .name = "syscon",
 388         },
 389         .probe          = syscon_probe,
 390         .id_table       = syscon_ids,
 391 };
 392
 393 static int __init syscon_init(void)
 394 {
 395         return platform_driver_register(&syscon_driver);
 396 }
 397 postcore_initcall(syscon_init);