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)
  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         if (!of_device_is_compatible(np, "syscon"))
  55                 return ERR_PTR(-EINVAL);
  56
  57         syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
  58         if (!syscon)
  59                 return ERR_PTR(-ENOMEM);
  60
  61         if (of_address_to_resource(np, 0, &res)) {
  62                 ret = -ENOMEM;
  63                 goto err_map;
  64         }
  65
  66         base = ioremap(res.start, resource_size(&res));
  67         if (!base) {
  68                 ret = -ENOMEM;
  69                 goto err_map;
  70         }
  71
  72         /* Parse the device's DT node for an endianness specification */
  73         if (of_property_read_bool(np, "big-endian"))
  74                 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
  75         else if (of_property_read_bool(np, "little-endian"))
  76                 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
  77         else if (of_property_read_bool(np, "native-endian"))
  78                 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
  79
  80         /*
  81          * search for reg-io-width property in DT. If it is not provided,
  82          * default to 4 bytes. regmap_init_mmio will return an error if values
  83          * are invalid so there is no need to check them here.
  84          */
  85         ret = of_property_read_u32(np, "reg-io-width", &reg_io_width);
  86         if (ret)
  87                 reg_io_width = 4;
  88
  89         ret = of_hwspin_lock_get_id(np, 0);
  90         if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
  91                 syscon_config.use_hwlock = true;
  92                 syscon_config.hwlock_id = ret;
  93                 syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
  94         } else if (ret < 0) {
  95                 switch (ret) {
  96                 case -ENOENT:
  97                         /* Ignore missing hwlock, it's optional. */
  98                         break;
  99                 default:
 100                         pr_err("Failed to retrieve valid hwlock: %d\n", ret);
 101                         /* fall-through */
 102                 case -EPROBE_DEFER:
 103                         goto err_regmap;
 104                 }
 105         }
 106
 107         syscon_config.name = of_node_full_name(np);
 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         syscon_config.name = of_node_full_name(np);
 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         clk = of_clk_get(np, 0);
 121         if (IS_ERR(clk)) {
 122                 ret = PTR_ERR(clk);
 123                 /* clock is optional */
 124                 if (ret != -ENOENT)
 125                         goto err_clk;
 126         } else {
 127                 ret = regmap_mmio_attach_clk(regmap, clk);
 128                 if (ret)
 129                         goto err_attach;
 130         }
 131
 132         syscon->regmap = regmap;
 133         syscon->np = np;
 134
 135         spin_lock(&syscon_list_slock);
 136         list_add_tail(&syscon->list, &syscon_list);
 137         spin_unlock(&syscon_list_slock);
 138
 139         return syscon;
 140
 141 err_attach:
 142         if (!IS_ERR(clk))
 143                 clk_put(clk);
 144 err_clk:
 145         regmap_exit(regmap);
 146 err_regmap:
 147         iounmap(base);
 148 err_map:
 149         kfree(syscon);
 150         return ERR_PTR(ret);
 151 }
 152
 153 struct regmap *syscon_node_to_regmap(struct device_node *np)
 154 {
 155         struct syscon *entry, *syscon = NULL;
 156
 157         spin_lock(&syscon_list_slock);
 158
 159         list_for_each_entry(entry, &syscon_list, list)
 160                 if (entry->np == np) {
 161                         syscon = entry;
 162                         break;
 163                 }
 164
 165         spin_unlock(&syscon_list_slock);
 166
 167         if (!syscon)
 168                 syscon = of_syscon_register(np);
 169
 170         if (IS_ERR(syscon))
 171                 return ERR_CAST(syscon);
 172
 173         return syscon->regmap;
 174 }
 175 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
 176
 177 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
 178 {
 179         struct device_node *syscon_np;
 180         struct regmap *regmap;
 181
 182         syscon_np = of_find_compatible_node(NULL, NULL, s);
 183         if (!syscon_np)
 184                 return ERR_PTR(-ENODEV);
 185
 186         regmap = syscon_node_to_regmap(syscon_np);
 187         of_node_put(syscon_np);
 188
 189         return regmap;
 190 }
 191 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
 192
 193 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
 194                                         const char *property)
 195 {
 196         struct device_node *syscon_np;
 197         struct regmap *regmap;
 198
 199         if (property)
 200                 syscon_np = of_parse_phandle(np, property, 0);
 201         else
 202                 syscon_np = np;
 203
 204         if (!syscon_np)
 205                 return ERR_PTR(-ENODEV);
 206
 207         regmap = syscon_node_to_regmap(syscon_np);
 208         of_node_put(syscon_np);
 209
 210         return regmap;
 211 }
 212 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
 213
 214 static int syscon_probe(struct platform_device *pdev)
 215 {
 216         struct device *dev = &pdev->dev;
 217         struct syscon_platform_data *pdata = dev_get_platdata(dev);
 218         struct syscon *syscon;
 219         struct regmap_config syscon_config = syscon_regmap_config;
 220         struct resource *res;
 221         void __iomem *base;
 222
 223         syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
 224         if (!syscon)
 225                 return -ENOMEM;
 226
 227         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 228         if (!res)
 229                 return -ENOENT;
 230
 231         base = devm_ioremap(dev, res->start, resource_size(res));
 232         if (!base)
 233                 return -ENOMEM;
 234
 235         syscon_config.max_register = res->end - res->start - 3;
 236         if (pdata)
 237                 syscon_config.name = pdata->label;
 238         syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
 239         if (IS_ERR(syscon->regmap)) {
 240                 dev_err(dev, "regmap init failed\n");
 241                 return PTR_ERR(syscon->regmap);
 242         }
 243
 244         platform_set_drvdata(pdev, syscon);
 245
 246         dev_dbg(dev, "regmap %pR registered\n", res);
 247
 248         return 0;
 249 }
 250
 251 static const struct platform_device_id syscon_ids[] = {
 252         { "syscon", },
 253         { }
 254 };
 255
 256 static struct platform_driver syscon_driver = {
 257         .driver = {
 258                 .name = "syscon",
 259         },
 260         .probe          = syscon_probe,
 261         .id_table       = syscon_ids,
 262 };
 263
 264 static int __init syscon_init(void)
 265 {
 266         return platform_driver_register(&syscon_driver);
 267 }
 268 postcore_initcall(syscon_init);