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/mutex.h> 19 #include <linux/of.h> 20 #include <linux/of_address.h> 21 #include <linux/of_platform.h> 22 #include <linux/platform_data/syscon.h> 23 #include <linux/platform_device.h> 24 #include <linux/regmap.h> 25 #include <linux/reset.h> 26 #include <linux/mfd/syscon.h> 27 #include <linux/slab.h> 28 29 static struct platform_driver syscon_driver; 30 31 static DEFINE_MUTEX(syscon_list_lock); 32 static LIST_HEAD(syscon_list); 33 34 struct syscon { 35 struct device_node *np; 36 struct regmap *regmap; 37 struct reset_control *reset; 38 struct list_head list; 39 }; 40 41 static const struct regmap_config syscon_regmap_config = { 42 .reg_bits = 32, 43 .val_bits = 32, 44 .reg_stride = 4, 45 }; 46 47 static struct syscon *of_syscon_register(struct device_node *np, bool check_res) 48 { 49 struct clk *clk; 50 struct regmap *regmap; 51 void __iomem *base; 52 u32 reg_io_width; 53 int ret; 54 struct regmap_config syscon_config = syscon_regmap_config; 55 struct resource res; 56 struct reset_control *reset; 57 58 WARN_ON(!mutex_is_locked(&syscon_list_lock)); 59 60 struct syscon *syscon __free(kfree) = kzalloc(sizeof(*syscon), GFP_KERNEL); 61 if (!syscon) 62 return ERR_PTR(-ENOMEM); 63 64 if (of_address_to_resource(np, 0, &res)) 65 return ERR_PTR(-ENOMEM); 66 67 base = of_iomap(np, 0); 68 if (!base) 69 return ERR_PTR(-ENOMEM); 70 71 /* Parse the device's DT node for an endianness specification */ 72 if (of_property_read_bool(np, "big-endian")) 73 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG; 74 else if (of_property_read_bool(np, "little-endian")) 75 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE; 76 else if (of_property_read_bool(np, "native-endian")) 77 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE; 78 79 /* 80 * search for reg-io-width property in DT. If it is not provided, 81 * default to 4 bytes. regmap_init_mmio will return an error if values 82 * are invalid so there is no need to check them here. 83 */ 84 ret = of_property_read_u32(np, "reg-io-width", ®_io_width); 85 if (ret) 86 reg_io_width = 4; 87 88 ret = of_hwspin_lock_get_id(np, 0); 89 if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) { 90 syscon_config.use_hwlock = true; 91 syscon_config.hwlock_id = ret; 92 syscon_config.hwlock_mode = HWLOCK_IRQSTATE; 93 } else if (ret < 0) { 94 switch (ret) { 95 case -ENOENT: 96 /* Ignore missing hwlock, it's optional. */ 97 break; 98 default: 99 pr_err("Failed to retrieve valid hwlock: %d\n", ret); 100 fallthrough; 101 case -EPROBE_DEFER: 102 goto err_regmap; 103 } 104 } 105 106 syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start); 107 if (!syscon_config.name) { 108 ret = -ENOMEM; 109 goto err_regmap; 110 } 111 syscon_config.reg_stride = reg_io_width; 112 syscon_config.val_bits = reg_io_width * 8; 113 syscon_config.max_register = resource_size(&res) - reg_io_width; 114 115 regmap = regmap_init_mmio(NULL, base, &syscon_config); 116 kfree(syscon_config.name); 117 if (IS_ERR(regmap)) { 118 pr_err("regmap init failed\n"); 119 ret = PTR_ERR(regmap); 120 goto err_regmap; 121 } 122 123 if (check_res) { 124 clk = of_clk_get(np, 0); 125 if (IS_ERR(clk)) { 126 ret = PTR_ERR(clk); 127 /* clock is optional */ 128 if (ret != -ENOENT) 129 goto err_clk; 130 } else { 131 ret = regmap_mmio_attach_clk(regmap, clk); 132 if (ret) 133 goto err_attach_clk; 134 } 135 136 reset = of_reset_control_get_optional_exclusive(np, NULL); 137 if (IS_ERR(reset)) { 138 ret = PTR_ERR(reset); 139 goto err_attach_clk; 140 } 141 142 ret = reset_control_deassert(reset); 143 if (ret) 144 goto err_reset; 145 } 146 147 syscon->regmap = regmap; 148 syscon->np = np; 149 150 list_add_tail(&syscon->list, &syscon_list); 151 152 return_ptr(syscon); 153 154 err_reset: 155 reset_control_put(reset); 156 err_attach_clk: 157 if (!IS_ERR(clk)) 158 clk_put(clk); 159 err_clk: 160 regmap_exit(regmap); 161 err_regmap: 162 iounmap(base); 163 return ERR_PTR(ret); 164 } 165 166 static struct regmap *device_node_get_regmap(struct device_node *np, 167 bool check_res) 168 { 169 struct syscon *entry, *syscon = NULL; 170 171 mutex_lock(&syscon_list_lock); 172 173 list_for_each_entry(entry, &syscon_list, list) 174 if (entry->np == np) { 175 syscon = entry; 176 break; 177 } 178 179 if (!syscon) 180 syscon = of_syscon_register(np, check_res); 181 182 mutex_unlock(&syscon_list_lock); 183 184 if (IS_ERR(syscon)) 185 return ERR_CAST(syscon); 186 187 return syscon->regmap; 188 } 189 190 /** 191 * of_syscon_register_regmap() - Register regmap for specified device node 192 * @np: Device tree node 193 * @regmap: Pointer to regmap object 194 * 195 * Register an externally created regmap object with syscon for the specified 196 * device tree node. This regmap will then be returned to client drivers using 197 * the syscon_regmap_lookup_by_phandle() API. 198 * 199 * Return: 0 on success, negative error code on failure. 200 */ 201 int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap) 202 { 203 struct syscon *entry, *syscon = NULL; 204 int ret; 205 206 if (!np || !regmap) 207 return -EINVAL; 208 209 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); 210 if (!syscon) 211 return -ENOMEM; 212 213 /* check if syscon entry already exists */ 214 mutex_lock(&syscon_list_lock); 215 216 list_for_each_entry(entry, &syscon_list, list) 217 if (entry->np == np) { 218 ret = -EEXIST; 219 goto err_unlock; 220 } 221 222 syscon->regmap = regmap; 223 syscon->np = np; 224 225 /* register the regmap in syscon list */ 226 list_add_tail(&syscon->list, &syscon_list); 227 mutex_unlock(&syscon_list_lock); 228 229 return 0; 230 231 err_unlock: 232 mutex_unlock(&syscon_list_lock); 233 kfree(syscon); 234 return ret; 235 } 236 EXPORT_SYMBOL_GPL(of_syscon_register_regmap); 237 238 struct regmap *device_node_to_regmap(struct device_node *np) 239 { 240 return device_node_get_regmap(np, false); 241 } 242 EXPORT_SYMBOL_GPL(device_node_to_regmap); 243 244 struct regmap *syscon_node_to_regmap(struct device_node *np) 245 { 246 if (!of_device_is_compatible(np, "syscon")) 247 return ERR_PTR(-EINVAL); 248 249 return device_node_get_regmap(np, true); 250 } 251 EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 252 253 struct regmap *syscon_regmap_lookup_by_compatible(const char *s) 254 { 255 struct device_node *syscon_np; 256 struct regmap *regmap; 257 258 syscon_np = of_find_compatible_node(NULL, NULL, s); 259 if (!syscon_np) 260 return ERR_PTR(-ENODEV); 261 262 regmap = syscon_node_to_regmap(syscon_np); 263 of_node_put(syscon_np); 264 265 return regmap; 266 } 267 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 268 269 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, 270 const char *property) 271 { 272 struct device_node *syscon_np; 273 struct regmap *regmap; 274 275 if (property) 276 syscon_np = of_parse_phandle(np, property, 0); 277 else 278 syscon_np = np; 279 280 if (!syscon_np) 281 return ERR_PTR(-ENODEV); 282 283 regmap = syscon_node_to_regmap(syscon_np); 284 285 if (property) 286 of_node_put(syscon_np); 287 288 return regmap; 289 } 290 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); 291 292 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np, 293 const char *property, 294 int arg_count, 295 unsigned int *out_args) 296 { 297 struct device_node *syscon_np; 298 struct of_phandle_args args; 299 struct regmap *regmap; 300 unsigned int index; 301 int rc; 302 303 rc = of_parse_phandle_with_fixed_args(np, property, arg_count, 304 0, &args); 305 if (rc) 306 return ERR_PTR(rc); 307 308 syscon_np = args.np; 309 if (!syscon_np) 310 return ERR_PTR(-ENODEV); 311 312 regmap = syscon_node_to_regmap(syscon_np); 313 for (index = 0; index < arg_count; index++) 314 out_args[index] = args.args[index]; 315 of_node_put(syscon_np); 316 317 return regmap; 318 } 319 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args); 320 321 /* 322 * It behaves the same as syscon_regmap_lookup_by_phandle() except where 323 * there is no regmap phandle. In this case, instead of returning -ENODEV, 324 * the function returns NULL. 325 */ 326 struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np, 327 const char *property) 328 { 329 struct regmap *regmap; 330 331 regmap = syscon_regmap_lookup_by_phandle(np, property); 332 if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV) 333 return NULL; 334 335 return regmap; 336 } 337 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional); 338 339 static int syscon_probe(struct platform_device *pdev) 340 { 341 struct device *dev = &pdev->dev; 342 struct syscon_platform_data *pdata = dev_get_platdata(dev); 343 struct syscon *syscon; 344 struct regmap_config syscon_config = syscon_regmap_config; 345 struct resource *res; 346 void __iomem *base; 347 348 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); 349 if (!syscon) 350 return -ENOMEM; 351 352 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 353 if (!res) 354 return -ENOENT; 355 356 base = devm_ioremap(dev, res->start, resource_size(res)); 357 if (!base) 358 return -ENOMEM; 359 360 syscon_config.max_register = resource_size(res) - 4; 361 if (pdata) 362 syscon_config.name = pdata->label; 363 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config); 364 if (IS_ERR(syscon->regmap)) { 365 dev_err(dev, "regmap init failed\n"); 366 return PTR_ERR(syscon->regmap); 367 } 368 369 platform_set_drvdata(pdev, syscon); 370 371 dev_dbg(dev, "regmap %pR registered\n", res); 372 373 return 0; 374 } 375 376 static const struct platform_device_id syscon_ids[] = { 377 { "syscon", }, 378 { } 379 }; 380 381 static struct platform_driver syscon_driver = { 382 .driver = { 383 .name = "syscon", 384 }, 385 .probe = syscon_probe, 386 .id_table = syscon_ids, 387 }; 388 389 static int __init syscon_init(void) 390 { 391 return platform_driver_register(&syscon_driver); 392 } 393 postcore_initcall(syscon_init); 394