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                         /* fall-through */
  99                 case -EPROBE_DEFER:
 100                         goto err_regmap;
 101                 }
 102         }
 103
 104         syscon_config.name = of_node_full_name(np);
 105         syscon_config.reg_stride = reg_io_width;
 106         syscon_config.val_bits = reg_io_width * 8;
 107         syscon_config.max_register = resource_size(&res) - reg_io_width;
 108
 109         regmap = regmap_init_mmio(NULL, base, &syscon_config);
 110         if (IS_ERR(regmap)) {
 111                 pr_err("regmap init failed\n");
 112                 ret = PTR_ERR(regmap);
 113                 goto err_regmap;
 114         }
 115
 116         if (check_clk) {
 117                 clk = of_clk_get(np, 0);
 118                 if (IS_ERR(clk)) {
 119                         ret = PTR_ERR(clk);
 120                         /* clock is optional */
 121                         if (ret != -ENOENT)
 122                                 goto err_clk;
 123                 } else {
 124                         ret = regmap_mmio_attach_clk(regmap, clk);
 125                         if (ret)
 126                                 goto err_attach;
 127                 }
 128         }
 129
 130         syscon->regmap = regmap;
 131         syscon->np = np;
 132
 133         spin_lock(&syscon_list_slock);
 134         list_add_tail(&syscon->list, &syscon_list);
 135         spin_unlock(&syscon_list_slock);
 136
 137         return syscon;
 138
 139 err_attach:
 140         if (!IS_ERR(clk))
 141                 clk_put(clk);
 142 err_clk:
 143         regmap_exit(regmap);
 144 err_regmap:
 145         iounmap(base);
 146 err_map:
 147         kfree(syscon);
 148         return ERR_PTR(ret);
 149 }
 150
 151 static struct regmap *device_node_get_regmap(struct device_node *np,
 152                                              bool check_clk)
 153 {
 154         struct syscon *entry, *syscon = NULL;
 155
 156         spin_lock(&syscon_list_slock);
 157
 158         list_for_each_entry(entry, &syscon_list, list)
 159                 if (entry->np == np) {
 160                         syscon = entry;
 161                         break;
 162                 }
 163
 164         spin_unlock(&syscon_list_slock);
 165
 166         if (!syscon)
 167                 syscon = of_syscon_register(np, check_clk);
 168
 169         if (IS_ERR(syscon))
 170                 return ERR_CAST(syscon);
 171
 172         return syscon->regmap;
 173 }
 174
 175 struct regmap *device_node_to_regmap(struct device_node *np)
 176 {
 177         return device_node_get_regmap(np, false);
 178 }
 179 EXPORT_SYMBOL_GPL(device_node_to_regmap);
 180
 181 struct regmap *syscon_node_to_regmap(struct device_node *np)
 182 {
 183         if (!of_device_is_compatible(np, "syscon"))
 184                 return ERR_PTR(-EINVAL);
 185
 186         return device_node_get_regmap(np, true);
 187 }
 188 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
 189
 190 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
 191 {
 192         struct device_node *syscon_np;
 193         struct regmap *regmap;
 194
 195         syscon_np = of_find_compatible_node(NULL, NULL, s);
 196         if (!syscon_np)
 197                 return ERR_PTR(-ENODEV);
 198
 199         regmap = syscon_node_to_regmap(syscon_np);
 200         of_node_put(syscon_np);
 201
 202         return regmap;
 203 }
 204 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
 205
 206 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
 207                                         const char *property)
 208 {
 209         struct device_node *syscon_np;
 210         struct regmap *regmap;
 211
 212         if (property)
 213                 syscon_np = of_parse_phandle(np, property, 0);
 214         else
 215                 syscon_np = np;
 216
 217         if (!syscon_np)
 218                 return ERR_PTR(-ENODEV);
 219
 220         regmap = syscon_node_to_regmap(syscon_np);
 221         of_node_put(syscon_np);
 222
 223         return regmap;
 224 }
 225 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
 226
 227 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
 228                                         const char *property,
 229                                         int arg_count,
 230                                         unsigned int *out_args)
 231 {
 232         struct device_node *syscon_np;
 233         struct of_phandle_args args;
 234         struct regmap *regmap;
 235         unsigned int index;
 236         int rc;
 237
 238         rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
 239                         0, &args);
 240         if (rc)
 241                 return ERR_PTR(rc);
 242
 243         syscon_np = args.np;
 244         if (!syscon_np)
 245                 return ERR_PTR(-ENODEV);
 246
 247         regmap = syscon_node_to_regmap(syscon_np);
 248         for (index = 0; index < arg_count; index++)
 249                 out_args[index] = args.args[index];
 250         of_node_put(syscon_np);
 251
 252         return regmap;
 253 }
 254 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);
 255
 256 static int syscon_probe(struct platform_device *pdev)
 257 {
 258         struct device *dev = &pdev->dev;
 259         struct syscon_platform_data *pdata = dev_get_platdata(dev);
 260         struct syscon *syscon;
 261         struct regmap_config syscon_config = syscon_regmap_config;
 262         struct resource *res;
 263         void __iomem *base;
 264
 265         syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
 266         if (!syscon)
 267                 return -ENOMEM;
 268
 269         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 270         if (!res)
 271                 return -ENOENT;
 272
 273         base = devm_ioremap(dev, res->start, resource_size(res));
 274         if (!base)
 275                 return -ENOMEM;
 276
 277         syscon_config.max_register = resource_size(res) - 4;
 278         if (pdata)
 279                 syscon_config.name = pdata->label;
 280         syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
 281         if (IS_ERR(syscon->regmap)) {
 282                 dev_err(dev, "regmap init failed\n");
 283                 return PTR_ERR(syscon->regmap);
 284         }
 285
 286         platform_set_drvdata(pdev, syscon);
 287
 288         dev_dbg(dev, "regmap %pR registered\n", res);
 289
 290         return 0;
 291 }
 292
 293 static const struct platform_device_id syscon_ids[] = {
 294         { "syscon", },
 295         { }
 296 };
 297
 298 static struct platform_driver syscon_driver = {
 299         .driver = {
 300                 .name = "syscon",
 301         },
 302         .probe          = syscon_probe,
 303         .id_table       = syscon_ids,
 304 };
 305
 306 static int __init syscon_init(void)
 307 {
 308         return platform_driver_register(&syscon_driver);
 309 }
 310 postcore_initcall(syscon_init);