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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * System Control Driver4 *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 28static struct platform_driver syscon_driver;29 30static DEFINE_SPINLOCK(syscon_list_slock);31static LIST_HEAD(syscon_list);32 33struct syscon {34 struct device_node *np;35 struct regmap *regmap;36 struct reset_control *reset;37 struct list_head list;38};39 40static const struct regmap_config syscon_regmap_config = {41 .reg_bits = 32,42 .val_bits = 32,43 .reg_stride = 4,44};45 46static 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 values79 * are invalid so there is no need to check them here.80 */81 ret = of_property_read_u32(np, "reg-io-width", ®_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;111 112 regmap = regmap_init_mmio(NULL, base, &syscon_config);113 kfree(syscon_config.name);114 if (IS_ERR(regmap)) {115 pr_err("regmap init failed\n");116 ret = PTR_ERR(regmap);117 goto err_regmap;118 }119 120 if (check_res) {121 clk = of_clk_get(np, 0);122 if (IS_ERR(clk)) {123 ret = PTR_ERR(clk);124 /* clock is optional */125 if (ret != -ENOENT)126 goto err_clk;127 } else {128 ret = regmap_mmio_attach_clk(regmap, clk);129 if (ret)130 goto err_attach_clk;131 }132 133 reset = of_reset_control_get_optional_exclusive(np, NULL);134 if (IS_ERR(reset)) {135 ret = PTR_ERR(reset);136 goto err_attach_clk;137 }138 139 ret = reset_control_deassert(reset);140 if (ret)141 goto err_reset;142 }143 144 syscon->regmap = regmap;145 syscon->np = np;146 147 spin_lock(&syscon_list_slock);148 list_add_tail(&syscon->list, &syscon_list);149 spin_unlock(&syscon_list_slock);150 151 return_ptr(syscon);152 153err_reset:154 reset_control_put(reset);155err_attach_clk:156 if (!IS_ERR(clk))157 clk_put(clk);158err_clk:159 regmap_exit(regmap);160err_regmap:161 iounmap(base);162 return ERR_PTR(ret);163}164 165static struct regmap *device_node_get_regmap(struct device_node *np,166 bool check_res)167{168 struct syscon *entry, *syscon = NULL;169 170 spin_lock(&syscon_list_slock);171 172 list_for_each_entry(entry, &syscon_list, list)173 if (entry->np == np) {174 syscon = entry;175 break;176 }177 178 spin_unlock(&syscon_list_slock);179 180 if (!syscon)181 syscon = of_syscon_register(np, check_res);182 183 if (IS_ERR(syscon))184 return ERR_CAST(syscon);185 186 return syscon->regmap;187}188 189/**190 * of_syscon_register_regmap() - Register regmap for specified device node191 * @np: Device tree node192 * @regmap: Pointer to regmap object193 *194 * Register an externally created regmap object with syscon for the specified195 * device tree node. This regmap will then be returned to client drivers using196 * the syscon_regmap_lookup_by_phandle() API.197 *198 * Return: 0 on success, negative error code on failure.199 */200int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap)201{202 struct syscon *entry, *syscon = NULL;203 int ret;204 205 if (!np || !regmap)206 return -EINVAL;207 208 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);209 if (!syscon)210 return -ENOMEM;211 212 /* check if syscon entry already exists */213 spin_lock(&syscon_list_slock);214 215 list_for_each_entry(entry, &syscon_list, list)216 if (entry->np == np) {217 ret = -EEXIST;218 goto err_unlock;219 }220 221 syscon->regmap = regmap;222 syscon->np = np;223 224 /* register the regmap in syscon list */225 list_add_tail(&syscon->list, &syscon_list);226 spin_unlock(&syscon_list_slock);227 228 return 0;229 230err_unlock:231 spin_unlock(&syscon_list_slock);232 kfree(syscon);233 return ret;234}235EXPORT_SYMBOL_GPL(of_syscon_register_regmap);236 237struct regmap *device_node_to_regmap(struct device_node *np)238{239 return device_node_get_regmap(np, false);240}241EXPORT_SYMBOL_GPL(device_node_to_regmap);242 243struct regmap *syscon_node_to_regmap(struct device_node *np)244{245 if (!of_device_is_compatible(np, "syscon"))246 return ERR_PTR(-EINVAL);247 248 return device_node_get_regmap(np, true);249}250EXPORT_SYMBOL_GPL(syscon_node_to_regmap);251 252struct regmap *syscon_regmap_lookup_by_compatible(const char *s)253{254 struct device_node *syscon_np;255 struct regmap *regmap;256 257 syscon_np = of_find_compatible_node(NULL, NULL, s);258 if (!syscon_np)259 return ERR_PTR(-ENODEV);260 261 regmap = syscon_node_to_regmap(syscon_np);262 of_node_put(syscon_np);263 264 return regmap;265}266EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);267 268struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,269 const char *property)270{271 struct device_node *syscon_np;272 struct regmap *regmap;273 274 if (property)275 syscon_np = of_parse_phandle(np, property, 0);276 else277 syscon_np = np;278 279 if (!syscon_np)280 return ERR_PTR(-ENODEV);281 282 regmap = syscon_node_to_regmap(syscon_np);283 284 if (property)285 of_node_put(syscon_np);286 287 return regmap;288}289EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);290 291struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np,292 const char *property,293 int arg_count,294 unsigned int *out_args)295{296 struct device_node *syscon_np;297 struct of_phandle_args args;298 struct regmap *regmap;299 unsigned int index;300 int rc;301 302 rc = of_parse_phandle_with_fixed_args(np, property, arg_count,303 0, &args);304 if (rc)305 return ERR_PTR(rc);306 307 syscon_np = args.np;308 if (!syscon_np)309 return ERR_PTR(-ENODEV);310 311 regmap = syscon_node_to_regmap(syscon_np);312 for (index = 0; index < arg_count; index++)313 out_args[index] = args.args[index];314 of_node_put(syscon_np);315 316 return regmap;317}318EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args);319 320/*321 * It behaves the same as syscon_regmap_lookup_by_phandle() except where322 * there is no regmap phandle. In this case, instead of returning -ENODEV,323 * the function returns NULL.324 */325struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np,326 const char *property)327{328 struct regmap *regmap;329 330 regmap = syscon_regmap_lookup_by_phandle(np, property);331 if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV)332 return NULL;333 334 return regmap;335}336EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional);337 338static int syscon_probe(struct platform_device *pdev)339{340 struct device *dev = &pdev->dev;341 struct syscon_platform_data *pdata = dev_get_platdata(dev);342 struct syscon *syscon;343 struct regmap_config syscon_config = syscon_regmap_config;344 struct resource *res;345 void __iomem *base;346 347 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);348 if (!syscon)349 return -ENOMEM;350 351 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);352 if (!res)353 return -ENOENT;354 355 base = devm_ioremap(dev, res->start, resource_size(res));356 if (!base)357 return -ENOMEM;358 359 syscon_config.max_register = resource_size(res) - 4;360 if (pdata)361 syscon_config.name = pdata->label;362 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);363 if (IS_ERR(syscon->regmap)) {364 dev_err(dev, "regmap init failed\n");365 return PTR_ERR(syscon->regmap);366 }367 368 platform_set_drvdata(pdev, syscon);369 370 dev_dbg(dev, "regmap %pR registered\n", res);371 372 return 0;373}374 375static const struct platform_device_id syscon_ids[] = {376 { "syscon", },377 { }378};379 380static struct platform_driver syscon_driver = {381 .driver = {382 .name = "syscon",383 },384 .probe = syscon_probe,385 .id_table = syscon_ids,386};387 388static int __init syscon_init(void)389{390 return platform_driver_register(&syscon_driver);391}392postcore_initcall(syscon_init);393