drivers/mfd/syscon.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * System Control Driver
0004  *
0005  * Copyright (C) 2012 Freescale Semiconductor, Inc.
0006  * Copyright (C) 2012 Linaro Ltd.
0007  *
0008  * Author: Dong Aisheng <dong.aisheng@linaro.org>
0009  */
0010
0011 #include <linux/clk.h>
0012 #include <linux/err.h>
0013 #include <linux/hwspinlock.h>
0014 #include <linux/io.h>
0015 #include <linux/init.h>
0016 #include <linux/list.h>
0017 #include <linux/of.h>
0018 #include <linux/of_address.h>
0019 #include <linux/of_platform.h>
0020 #include <linux/platform_data/syscon.h>
0021 #include <linux/platform_device.h>
0022 #include <linux/regmap.h>
0023 #include <linux/mfd/syscon.h>
0024 #include <linux/slab.h>
0025
0026 static struct platform_driver syscon_driver;
0027
0028 static DEFINE_SPINLOCK(syscon_list_slock);
0029 static LIST_HEAD(syscon_list);
0030
0031 struct syscon {
0032     struct device_node *np;
0033     struct regmap *regmap;
0034     struct list_head list;
0035 };
0036
0037 static const struct regmap_config syscon_regmap_config = {
0038     .reg_bits = 32,
0039     .val_bits = 32,
0040     .reg_stride = 4,
0041 };
0042
0043 static struct syscon *of_syscon_register(struct device_node *np, bool check_clk)
0044 {
0045     struct clk *clk;
0046     struct syscon *syscon;
0047     struct regmap *regmap;
0048     void __iomem *base;
0049     u32 reg_io_width;
0050     int ret;
0051     struct regmap_config syscon_config = syscon_regmap_config;
0052     struct resource res;
0053
0054     syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
0055     if (!syscon)
0056         return ERR_PTR(-ENOMEM);
0057
0058     if (of_address_to_resource(np, 0, &res)) {
0059         ret = -ENOMEM;
0060         goto err_map;
0061     }
0062
0063     base = of_iomap(np, 0);
0064     if (!base) {
0065         ret = -ENOMEM;
0066         goto err_map;
0067     }
0068
0069     /* Parse the device's DT node for an endianness specification */
0070     if (of_property_read_bool(np, "big-endian"))
0071         syscon_config.val_format_endian = REGMAP_ENDIAN_BIG;
0072     else if (of_property_read_bool(np, "little-endian"))
0073         syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
0074     else if (of_property_read_bool(np, "native-endian"))
0075         syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE;
0076
0077     /*
0078      * search for reg-io-width property in DT. If it is not provided,
0079      * default to 4 bytes. regmap_init_mmio will return an error if values
0080      * are invalid so there is no need to check them here.
0081      */
0082     ret = of_property_read_u32(np, "reg-io-width", &reg_io_width);
0083     if (ret)
0084         reg_io_width = 4;
0085
0086     ret = of_hwspin_lock_get_id(np, 0);
0087     if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) {
0088         syscon_config.use_hwlock = true;
0089         syscon_config.hwlock_id = ret;
0090         syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
0091     } else if (ret < 0) {
0092         switch (ret) {
0093         case -ENOENT:
0094             /* Ignore missing hwlock, it's optional. */
0095             break;
0096         default:
0097             pr_err("Failed to retrieve valid hwlock: %d\n", ret);
0098             fallthrough;
0099         case -EPROBE_DEFER:
0100             goto err_regmap;
0101         }
0102     }
0103
0104     syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start);
0105     syscon_config.reg_stride = reg_io_width;
0106     syscon_config.val_bits = reg_io_width * 8;
0107     syscon_config.max_register = resource_size(&res) - reg_io_width;
0108
0109     regmap = regmap_init_mmio(NULL, base, &syscon_config);
0110     kfree(syscon_config.name);
0111     if (IS_ERR(regmap)) {
0112         pr_err("regmap init failed\n");
0113         ret = PTR_ERR(regmap);
0114         goto err_regmap;
0115     }
0116
0117     if (check_clk) {
0118         clk = of_clk_get(np, 0);
0119         if (IS_ERR(clk)) {
0120             ret = PTR_ERR(clk);
0121             /* clock is optional */
0122             if (ret != -ENOENT)
0123                 goto err_clk;
0124         } else {
0125             ret = regmap_mmio_attach_clk(regmap, clk);
0126             if (ret)
0127                 goto err_attach;
0128         }
0129     }
0130
0131     syscon->regmap = regmap;
0132     syscon->np = np;
0133
0134     spin_lock(&syscon_list_slock);
0135     list_add_tail(&syscon->list, &syscon_list);
0136     spin_unlock(&syscon_list_slock);
0137
0138     return syscon;
0139
0140 err_attach:
0141     if (!IS_ERR(clk))
0142         clk_put(clk);
0143 err_clk:
0144     regmap_exit(regmap);
0145 err_regmap:
0146     iounmap(base);
0147 err_map:
0148     kfree(syscon);
0149     return ERR_PTR(ret);
0150 }
0151
0152 static struct regmap *device_node_get_regmap(struct device_node *np,
0153                          bool check_clk)
0154 {
0155     struct syscon *entry, *syscon = NULL;
0156
0157     spin_lock(&syscon_list_slock);
0158
0159     list_for_each_entry(entry, &syscon_list, list)
0160         if (entry->np == np) {
0161             syscon = entry;
0162             break;
0163         }
0164
0165     spin_unlock(&syscon_list_slock);
0166
0167     if (!syscon)
0168         syscon = of_syscon_register(np, check_clk);
0169
0170     if (IS_ERR(syscon))
0171         return ERR_CAST(syscon);
0172
0173     return syscon->regmap;
0174 }
0175
0176 struct regmap *device_node_to_regmap(struct device_node *np)
0177 {
0178     return device_node_get_regmap(np, false);
0179 }
0180 EXPORT_SYMBOL_GPL(device_node_to_regmap);
0181
0182 struct regmap *syscon_node_to_regmap(struct device_node *np)
0183 {
0184     if (!of_device_is_compatible(np, "syscon"))
0185         return ERR_PTR(-EINVAL);
0186
0187     return device_node_get_regmap(np, true);
0188 }
0189 EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
0190
0191 struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
0192 {
0193     struct device_node *syscon_np;
0194     struct regmap *regmap;
0195
0196     syscon_np = of_find_compatible_node(NULL, NULL, s);
0197     if (!syscon_np)
0198         return ERR_PTR(-ENODEV);
0199
0200     regmap = syscon_node_to_regmap(syscon_np);
0201     of_node_put(syscon_np);
0202
0203     return regmap;
0204 }
0205 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
0206
0207 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
0208                     const char *property)
0209 {
0210     struct device_node *syscon_np;
0211     struct regmap *regmap;
0212
0213     if (property)
0214         syscon_np = of_parse_phandle(np, property, 0);
0215     else
0216         syscon_np = np;
0217
0218     if (!syscon_np)
0219         return ERR_PTR(-ENODEV);
0220
0221     regmap = syscon_node_to_regmap(syscon_np);
0222     of_node_put(syscon_np);
0223
0224     return regmap;
0225 }
0226 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
0227
0228 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,
0229                     const char *property,
0230                     int arg_count,
0231                     unsigned int *out_args)
0232 {
0233     struct device_node *syscon_np;
0234     struct of_phandle_args args;
0235     struct regmap *regmap;
0236     unsigned int index;
0237     int rc;
0238
0239     rc = of_parse_phandle_with_fixed_args(np, property, arg_count,
0240             0, &args);
0241     if (rc)
0242         return ERR_PTR(rc);
0243
0244     syscon_np = args.np;
0245     if (!syscon_np)
0246         return ERR_PTR(-ENODEV);
0247
0248     regmap = syscon_node_to_regmap(syscon_np);
0249     for (index = 0; index < arg_count; index++)
0250         out_args[index] = args.args[index];
0251     of_node_put(syscon_np);
0252
0253     return regmap;
0254 }
0255 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);
0256
0257 /*
0258  * It behaves the same as syscon_regmap_lookup_by_phandle() except where
0259  * there is no regmap phandle. In this case, instead of returning -ENODEV,
0260  * the function returns NULL.
0261  */
0262 struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,
0263                     const char *property)
0264 {
0265     struct regmap *regmap;
0266
0267     regmap = syscon_regmap_lookup_by_phandle(np, property);
0268     if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)
0269         return NULL;
0270
0271     return regmap;
0272 }
0273 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);
0274
0275 static int syscon_probe(struct platform_device *pdev)
0276 {
0277     struct device *dev = &pdev->dev;
0278     struct syscon_platform_data *pdata = dev_get_platdata(dev);
0279     struct syscon *syscon;
0280     struct regmap_config syscon_config = syscon_regmap_config;
0281     struct resource *res;
0282     void __iomem *base;
0283
0284     syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);
0285     if (!syscon)
0286         return -ENOMEM;
0287
0288     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
0289     if (!res)
0290         return -ENOENT;
0291
0292     base = devm_ioremap(dev, res->start, resource_size(res));
0293     if (!base)
0294         return -ENOMEM;
0295
0296     syscon_config.max_register = resource_size(res) - 4;
0297     if (pdata)
0298         syscon_config.name = pdata->label;
0299     syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
0300     if (IS_ERR(syscon->regmap)) {
0301         dev_err(dev, "regmap init failed\n");
0302         return PTR_ERR(syscon->regmap);
0303     }
0304
0305     platform_set_drvdata(pdev, syscon);
0306
0307     dev_dbg(dev, "regmap %pR registered\n", res);
0308
0309     return 0;
0310 }
0311
0312 static const struct platform_device_id syscon_ids[] = {
0313     { "syscon", },
0314     { }
0315 };
0316
0317 static struct platform_driver syscon_driver = {
0318     .driver = {
0319         .name = "syscon",
0320     },
0321     .probe      = syscon_probe,
0322     .id_table   = syscon_ids,
0323 };
0324
0325 static int __init syscon_init(void)
0326 {
0327     return platform_driver_register(&syscon_driver);
0328 }
0329 postcore_initcall(syscon_init);