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/reset.h> 24 #include <linux/mfd/syscon.h> 25 #include <linux/slab.h> 26 27 static struct platform_driver syscon_driver; 28 29 static DEFINE_SPINLOCK(syscon_list_slock); 30 static LIST_HEAD(syscon_list); 31 32 struct syscon { 33 struct device_node *np; 34 struct regmap *regmap; 35 struct reset_control *reset; 36 struct list_head list; 37 }; 38 39 static const struct regmap_config syscon_regmap_config = { 40 .reg_bits = 32, 41 .val_bits = 32, 42 .reg_stride = 4, 43 }; 44 45 static struct syscon *of_syscon_register(struct device_node *np, bool check_res) 46 { 47 struct clk *clk; 48 struct syscon *syscon; 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 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 = of_iomap(np, 0); 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", ®_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 fallthrough; 102 case -EPROBE_DEFER: 103 goto err_regmap; 104 } 105 } 106 107 syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start); 108 if (!syscon_config.name) { 109 ret = -ENOMEM; 110 goto err_regmap; 111 } 112 syscon_config.reg_stride = reg_io_width; 113 syscon_config.val_bits = reg_io_width * 8; 114 syscon_config.max_register = resource_size(&res) - reg_io_width; 115 116 regmap = regmap_init_mmio(NULL, base, &syscon_config); 117 kfree(syscon_config.name); 118 if (IS_ERR(regmap)) { 119 pr_err("regmap init failed\n"); 120 ret = PTR_ERR(regmap); 121 goto err_regmap; 122 } 123 124 if (check_res) { 125 clk = of_clk_get(np, 0); 126 if (IS_ERR(clk)) { 127 ret = PTR_ERR(clk); 128 /* clock is optional */ 129 if (ret != -ENOENT) 130 goto err_clk; 131 } else { 132 ret = regmap_mmio_attach_clk(regmap, clk); 133 if (ret) 134 goto err_attach_clk; 135 } 136 137 reset = of_reset_control_get_optional_exclusive(np, NULL); 138 if (IS_ERR(reset)) { 139 ret = PTR_ERR(reset); 140 goto err_attach_clk; 141 } 142 143 ret = reset_control_deassert(reset); 144 if (ret) 145 goto err_reset; 146 } 147 148 syscon->regmap = regmap; 149 syscon->np = np; 150 151 spin_lock(&syscon_list_slock); 152 list_add_tail(&syscon->list, &syscon_list); 153 spin_unlock(&syscon_list_slock); 154 155 return syscon; 156 157 err_reset: 158 reset_control_put(reset); 159 err_attach_clk: 160 if (!IS_ERR(clk)) 161 clk_put(clk); 162 err_clk: 163 regmap_exit(regmap); 164 err_regmap: 165 iounmap(base); 166 err_map: 167 kfree(syscon); 168 return ERR_PTR(ret); 169 } 170 171 static struct regmap *device_node_get_regmap(struct device_node *np, 172 bool check_res) 173 { 174 struct syscon *entry, *syscon = NULL; 175 176 spin_lock(&syscon_list_slock); 177 178 list_for_each_entry(entry, &syscon_list, list) 179 if (entry->np == np) { 180 syscon = entry; 181 break; 182 } 183 184 spin_unlock(&syscon_list_slock); 185 186 if (!syscon) 187 syscon = of_syscon_register(np, check_res); 188 189 if (IS_ERR(syscon)) 190 return ERR_CAST(syscon); 191 192 return syscon->regmap; 193 } 194 195 /** 196 * of_syscon_register_regmap() - Register regmap for specified device node 197 * @np: Device tree node 198 * @regmap: Pointer to regmap object 199 * 200 * Register an externally created regmap object with syscon for the specified 201 * device tree node. This regmap will then be returned to client drivers using 202 * the syscon_regmap_lookup_by_phandle() API. 203 * 204 * Return: 0 on success, negative error code on failure. 205 */ 206 int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap) 207 { 208 struct syscon *entry, *syscon = NULL; 209 int ret; 210 211 if (!np || !regmap) 212 return -EINVAL; 213 214 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); 215 if (!syscon) 216 return -ENOMEM; 217 218 /* check if syscon entry already exists */ 219 spin_lock(&syscon_list_slock); 220 221 list_for_each_entry(entry, &syscon_list, list) 222 if (entry->np == np) { 223 ret = -EEXIST; 224 goto err_unlock; 225 } 226 227 syscon->regmap = regmap; 228 syscon->np = np; 229 230 /* register the regmap in syscon list */ 231 list_add_tail(&syscon->list, &syscon_list); 232 spin_unlock(&syscon_list_slock); 233 234 return 0; 235 236 err_unlock: 237 spin_unlock(&syscon_list_slock); 238 kfree(syscon); 239 return ret; 240 } 241 EXPORT_SYMBOL_GPL(of_syscon_register_regmap); 242 243 struct regmap *device_node_to_regmap(struct device_node *np) 244 { 245 return device_node_get_regmap(np, false); 246 } 247 EXPORT_SYMBOL_GPL(device_node_to_regmap); 248 249 struct regmap *syscon_node_to_regmap(struct device_node *np) 250 { 251 if (!of_device_is_compatible(np, "syscon")) 252 return ERR_PTR(-EINVAL); 253 254 return device_node_get_regmap(np, true); 255 } 256 EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 257 258 struct regmap *syscon_regmap_lookup_by_compatible(const char *s) 259 { 260 struct device_node *syscon_np; 261 struct regmap *regmap; 262 263 syscon_np = of_find_compatible_node(NULL, NULL, s); 264 if (!syscon_np) 265 return ERR_PTR(-ENODEV); 266 267 regmap = syscon_node_to_regmap(syscon_np); 268 of_node_put(syscon_np); 269 270 return regmap; 271 } 272 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 273 274 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, 275 const char *property) 276 { 277 struct device_node *syscon_np; 278 struct regmap *regmap; 279 280 if (property) 281 syscon_np = of_parse_phandle(np, property, 0); 282 else 283 syscon_np = np; 284 285 if (!syscon_np) 286 return ERR_PTR(-ENODEV); 287 288 regmap = syscon_node_to_regmap(syscon_np); 289 290 if (property) 291 of_node_put(syscon_np); 292 293 return regmap; 294 } 295 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); 296 297 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np, 298 const char *property, 299 int arg_count, 300 unsigned int *out_args) 301 { 302 struct device_node *syscon_np; 303 struct of_phandle_args args; 304 struct regmap *regmap; 305 unsigned int index; 306 int rc; 307 308 rc = of_parse_phandle_with_fixed_args(np, property, arg_count, 309 0, &args); 310 if (rc) 311 return ERR_PTR(rc); 312 313 syscon_np = args.np; 314 if (!syscon_np) 315 return ERR_PTR(-ENODEV); 316 317 regmap = syscon_node_to_regmap(syscon_np); 318 for (index = 0; index < arg_count; index++) 319 out_args[index] = args.args[index]; 320 of_node_put(syscon_np); 321 322 return regmap; 323 } 324 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args); 325 326 /* 327 * It behaves the same as syscon_regmap_lookup_by_phandle() except where 328 * there is no regmap phandle. In this case, instead of returning -ENODEV, 329 * the function returns NULL. 330 */ 331 struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np, 332 const char *property) 333 { 334 struct regmap *regmap; 335 336 regmap = syscon_regmap_lookup_by_phandle(np, property); 337 if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV) 338 return NULL; 339 340 return regmap; 341 } 342 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional); 343 344 static int syscon_probe(struct platform_device *pdev) 345 { 346 struct device *dev = &pdev->dev; 347 struct syscon_platform_data *pdata = dev_get_platdata(dev); 348 struct syscon *syscon; 349 struct regmap_config syscon_config = syscon_regmap_config; 350 struct resource *res; 351 void __iomem *base; 352 353 syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL); 354 if (!syscon) 355 return -ENOMEM; 356 357 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 358 if (!res) 359 return -ENOENT; 360 361 base = devm_ioremap(dev, res->start, resource_size(res)); 362 if (!base) 363 return -ENOMEM; 364 365 syscon_config.max_register = resource_size(res) - 4; 366 if (pdata) 367 syscon_config.name = pdata->label; 368 syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config); 369 if (IS_ERR(syscon->regmap)) { 370 dev_err(dev, "regmap init failed\n"); 371 return PTR_ERR(syscon->regmap); 372 } 373 374 platform_set_drvdata(pdev, syscon); 375 376 dev_dbg(dev, "regmap %pR registered\n", res); 377 378 return 0; 379 } 380 381 static const struct platform_device_id syscon_ids[] = { 382 { "syscon", }, 383 { } 384 }; 385 386 static struct platform_driver syscon_driver = { 387 .driver = { 388 .name = "syscon", 389 }, 390 .probe = syscon_probe, 391 .id_table = syscon_ids, 392 }; 393 394 static int __init syscon_init(void) 395 { 396 return platform_driver_register(&syscon_driver); 397 } 398 postcore_initcall(syscon_init); 399