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/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 28 static struct platform_driver syscon_driver; 29 30 static DEFINE_SPINLOCK(syscon_list_slock); 31 static LIST_HEAD(syscon_list); 32 33 struct syscon { 34 struct device_node *np; 35 struct regmap *regmap; 36 struct reset_control *reset; 37 struct list_head list; 38 }; 39 40 static const struct regmap_config syscon_regmap_config = { 41 .reg_bits = 32, 42 .val_bits = 32, 43 .reg_stride = 4, 44 }; 45 46 static 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 values 79 * 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 if (!syscon_config.max_register) 112 syscon_config.max_register_is_0 = true; 113 114 regmap = regmap_init_mmio(NULL, base, &syscon_config); 115 kfree(syscon_config.name); 116 if (IS_ERR(regmap)) { 117 pr_err("regmap init failed\n"); 118 ret = PTR_ERR(regmap); 119 goto err_regmap; 120 } 121 122 if (check_res) { 123 clk = of_clk_get(np, 0); 124 if (IS_ERR(clk)) { 125 ret = PTR_ERR(clk); 126 /* clock is optional */ 127 if (ret != -ENOENT) 128 goto err_clk; 129 } else { 130 ret = regmap_mmio_attach_clk(regmap, clk); 131 if (ret) 132 goto err_attach_clk; 133 } 134 135 reset = of_reset_control_get_optional_exclusive(np, NULL); 136 if (IS_ERR(reset)) { 137 ret = PTR_ERR(reset); 138 goto err_attach_clk; 139 } 140 141 ret = reset_control_deassert(reset); 142 if (ret) 143 goto err_reset; 144 } 145 146 syscon->regmap = regmap; 147 syscon->np = np; 148 149 spin_lock(&syscon_list_slock); 150 list_add_tail(&syscon->list, &syscon_list); 151 spin_unlock(&syscon_list_slock); 152 153 return_ptr(syscon); 154 155 err_reset: 156 reset_control_put(reset); 157 err_attach_clk: 158 if (!IS_ERR(clk)) 159 clk_put(clk); 160 err_clk: 161 regmap_exit(regmap); 162 err_regmap: 163 iounmap(base); 164 return ERR_PTR(ret); 165 } 166 167 static struct regmap *device_node_get_regmap(struct device_node *np, 168 bool check_res) 169 { 170 struct syscon *entry, *syscon = NULL; 171 172 spin_lock(&syscon_list_slock); 173 174 list_for_each_entry(entry, &syscon_list, list) 175 if (entry->np == np) { 176 syscon = entry; 177 break; 178 } 179 180 spin_unlock(&syscon_list_slock); 181 182 if (!syscon) 183 syscon = of_syscon_register(np, check_res); 184 185 if (IS_ERR(syscon)) 186 return ERR_CAST(syscon); 187 188 return syscon->regmap; 189 } 190 191 /** 192 * of_syscon_register_regmap() - Register regmap for specified device node 193 * @np: Device tree node 194 * @regmap: Pointer to regmap object 195 * 196 * Register an externally created regmap object with syscon for the specified 197 * device tree node. This regmap will then be returned to client drivers using 198 * the syscon_regmap_lookup_by_phandle() API. 199 * 200 * Return: 0 on success, negative error code on failure. 201 */ 202 int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap) 203 { 204 struct syscon *entry, *syscon = NULL; 205 int ret; 206 207 if (!np || !regmap) 208 return -EINVAL; 209 210 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); 211 if (!syscon) 212 return -ENOMEM; 213 214 /* check if syscon entry already exists */ 215 spin_lock(&syscon_list_slock); 216 217 list_for_each_entry(entry, &syscon_list, list) 218 if (entry->np == np) { 219 ret = -EEXIST; 220 goto err_unlock; 221 } 222 223 syscon->regmap = regmap; 224 syscon->np = np; 225 226 /* register the regmap in syscon list */ 227 list_add_tail(&syscon->list, &syscon_list); 228 spin_unlock(&syscon_list_slock); 229 230 return 0; 231 232 err_unlock: 233 spin_unlock(&syscon_list_slock); 234 kfree(syscon); 235 return ret; 236 } 237 EXPORT_SYMBOL_GPL(of_syscon_register_regmap); 238 239 struct regmap *device_node_to_regmap(struct device_node *np) 240 { 241 return device_node_get_regmap(np, false); 242 } 243 EXPORT_SYMBOL_GPL(device_node_to_regmap); 244 245 struct regmap *syscon_node_to_regmap(struct device_node *np) 246 { 247 if (!of_device_is_compatible(np, "syscon")) 248 return ERR_PTR(-EINVAL); 249 250 return device_node_get_regmap(np, true); 251 } 252 EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 253 254 struct regmap *syscon_regmap_lookup_by_compatible(const char *s) 255 { 256 struct device_node *syscon_np; 257 struct regmap *regmap; 258 259 syscon_np = of_find_compatible_node(NULL, NULL, s); 260 if (!syscon_np) 261 return ERR_PTR(-ENODEV); 262 263 regmap = syscon_node_to_regmap(syscon_np); 264 of_node_put(syscon_np); 265 266 return regmap; 267 } 268 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 269 270 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, 271 const char *property) 272 { 273 struct device_node *syscon_np; 274 struct regmap *regmap; 275 276 if (property) 277 syscon_np = of_parse_phandle(np, property, 0); 278 else 279 syscon_np = np; 280 281 if (!syscon_np) 282 return ERR_PTR(-ENODEV); 283 284 regmap = syscon_node_to_regmap(syscon_np); 285 286 if (property) 287 of_node_put(syscon_np); 288 289 return regmap; 290 } 291 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); 292 293 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np, 294 const char *property, 295 int arg_count, 296 unsigned int *out_args) 297 { 298 struct device_node *syscon_np; 299 struct of_phandle_args args; 300 struct regmap *regmap; 301 unsigned int index; 302 int rc; 303 304 rc = of_parse_phandle_with_fixed_args(np, property, arg_count, 305 0, &args); 306 if (rc) 307 return ERR_PTR(rc); 308 309 syscon_np = args.np; 310 if (!syscon_np) 311 return ERR_PTR(-ENODEV); 312 313 regmap = syscon_node_to_regmap(syscon_np); 314 for (index = 0; index < arg_count; index++) 315 out_args[index] = args.args[index]; 316 of_node_put(syscon_np); 317 318 return regmap; 319 } 320 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args); 321 322 /* 323 * It behaves the same as syscon_regmap_lookup_by_phandle() except where 324 * there is no regmap phandle. In this case, instead of returning -ENODEV, 325 * the function returns NULL. 326 */ 327 struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np, 328 const char *property) 329 { 330 struct regmap *regmap; 331 332 regmap = syscon_regmap_lookup_by_phandle(np, property); 333 if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV) 334 return NULL; 335 336 return regmap; 337 } 338 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional); 339 340 static int syscon_probe(struct platform_device *pdev) 341 { 342 struct device *dev = &pdev->dev; 343 struct syscon_platform_data *pdata = dev_get_platdata(dev); 344 struct syscon *syscon; 345 struct regmap_config syscon_config = syscon_regmap_config; 346 struct resource *res; 347 void __iomem *base; 348 349 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); 350 if (!syscon) 351 return -ENOMEM; 352 353 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 354 if (!res) 355 return -ENOENT; 356 357 base = devm_ioremap(dev, res->start, resource_size(res)); 358 if (!base) 359 return -ENOMEM; 360 361 syscon_config.max_register = resource_size(res) - 4; 362 if (!syscon_config.max_register) 363 syscon_config.max_register_is_0 = true; 364 365 if (pdata) 366 syscon_config.name = pdata->label; 367 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config); 368 if (IS_ERR(syscon->regmap)) { 369 dev_err(dev, "regmap init failed\n"); 370 return PTR_ERR(syscon->regmap); 371 } 372 373 platform_set_drvdata(pdev, syscon); 374 375 dev_dbg(dev, "regmap %pR registered\n", res); 376 377 return 0; 378 } 379 380 static const struct platform_device_id syscon_ids[] = { 381 { "syscon", }, 382 { } 383 }; 384 385 static struct platform_driver syscon_driver = { 386 .driver = { 387 .name = "syscon", 388 }, 389 .probe = syscon_probe, 390 .id_table = syscon_ids, 391 }; 392 393 static int __init syscon_init(void) 394 { 395 return platform_driver_register(&syscon_driver); 396 } 397 postcore_initcall(syscon_init); 398