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; 111 112 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); 152 153 err_reset: 154 reset_control_put(reset); 155 err_attach_clk: 156 if (!IS_ERR(clk)) 157 clk_put(clk); 158 err_clk: 159 regmap_exit(regmap); 160 err_regmap: 161 iounmap(base); 162 return ERR_PTR(ret); 163 } 164 165 static 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 node 191 * @np: Device tree node 192 * @regmap: Pointer to regmap object 193 * 194 * Register an externally created regmap object with syscon for the specified 195 * device tree node. This regmap will then be returned to client drivers using 196 * the syscon_regmap_lookup_by_phandle() API. 197 * 198 * Return: 0 on success, negative error code on failure. 199 */ 200 int 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; 229 230 err_unlock: 231 spin_unlock(&syscon_list_slock); 232 kfree(syscon); 233 return ret; 234 } 235 EXPORT_SYMBOL_GPL(of_syscon_register_regmap); 236 237 struct regmap *device_node_to_regmap(struct device_node *np) 238 { 239 return device_node_get_regmap(np, false); 240 } 241 EXPORT_SYMBOL_GPL(device_node_to_regmap); 242 243 struct 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 } 250 EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 251 252 struct 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 } 266 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 267 268 struct 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 else 277 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 } 289 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); 290 291 struct 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 } 318 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args); 319 320 /* 321 * It behaves the same as syscon_regmap_lookup_by_phandle() except where 322 * there is no regmap phandle. In this case, instead of returning -ENODEV, 323 * the function returns NULL. 324 */ 325 struct 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 } 336 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional); 337 338 static 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 } 374 375 static const struct platform_device_id syscon_ids[] = { 376 { "syscon", }, 377 { } 378 }; 379 380 static struct platform_driver syscon_driver = { 381 .driver = { 382 .name = "syscon", 383 }, 384 .probe = syscon_probe, 385 .id_table = syscon_ids, 386 }; 387 388 static int __init syscon_init(void) 389 { 390 return platform_driver_register(&syscon_driver); 391 } 392 postcore_initcall(syscon_init); 393