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/list.h> 16 #include <linux/mutex.h> 17 #include <linux/of.h> 18 #include <linux/of_address.h> 19 #include <linux/regmap.h> 20 #include <linux/reset.h> 21 #include <linux/mfd/syscon.h> 22 #include <linux/slab.h> 23 24 static DEFINE_MUTEX(syscon_list_lock); 25 static LIST_HEAD(syscon_list); 26 27 struct syscon { 28 struct device_node *np; 29 struct regmap *regmap; 30 struct reset_control *reset; 31 struct list_head list; 32 }; 33 34 static const struct regmap_config syscon_regmap_config = { 35 .reg_bits = 32, 36 .val_bits = 32, 37 .reg_stride = 4, 38 }; 39 40 static struct syscon *of_syscon_register(struct device_node *np, bool check_res) 41 { 42 struct clk *clk; 43 struct regmap *regmap; 44 void __iomem *base; 45 u32 reg_io_width; 46 int ret; 47 struct regmap_config syscon_config = syscon_regmap_config; 48 struct resource res; 49 struct reset_control *reset; 50 resource_size_t res_size; 51 52 WARN_ON(!mutex_is_locked(&syscon_list_lock)); 53 54 struct syscon *syscon __free(kfree) = kzalloc(sizeof(*syscon), GFP_KERNEL); 55 if (!syscon) 56 return ERR_PTR(-ENOMEM); 57 58 if (of_address_to_resource(np, 0, &res)) 59 return ERR_PTR(-ENOMEM); 60 61 base = of_iomap(np, 0); 62 if (!base) 63 return ERR_PTR(-ENOMEM); 64 65 /* Parse the device's DT node for an endianness specification */ 66 if (of_property_read_bool(np, "big-endian")) 67 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG; 68 else if (of_property_read_bool(np, "little-endian")) 69 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE; 70 else if (of_property_read_bool(np, "native-endian")) 71 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE; 72 73 /* 74 * search for reg-io-width property in DT. If it is not provided, 75 * default to 4 bytes. regmap_init_mmio will return an error if values 76 * are invalid so there is no need to check them here. 77 */ 78 ret = of_property_read_u32(np, "reg-io-width", ®_io_width); 79 if (ret) 80 reg_io_width = 4; 81 82 ret = of_hwspin_lock_get_id(np, 0); 83 if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) { 84 syscon_config.use_hwlock = true; 85 syscon_config.hwlock_id = ret; 86 syscon_config.hwlock_mode = HWLOCK_IRQSTATE; 87 } else if (ret < 0) { 88 switch (ret) { 89 case -ENOENT: 90 /* Ignore missing hwlock, it's optional. */ 91 break; 92 default: 93 pr_err("Failed to retrieve valid hwlock: %d\n", ret); 94 fallthrough; 95 case -EPROBE_DEFER: 96 goto err_regmap; 97 } 98 } 99 100 res_size = resource_size(&res); 101 if (res_size < reg_io_width) { 102 ret = -EFAULT; 103 goto err_regmap; 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 = res_size - reg_io_width; 114 if (!syscon_config.max_register) 115 syscon_config.max_register_is_0 = true; 116 117 regmap = regmap_init_mmio(NULL, base, &syscon_config); 118 kfree(syscon_config.name); 119 if (IS_ERR(regmap)) { 120 pr_err("regmap init failed\n"); 121 ret = PTR_ERR(regmap); 122 goto err_regmap; 123 } 124 125 if (check_res) { 126 clk = of_clk_get(np, 0); 127 if (IS_ERR(clk)) { 128 ret = PTR_ERR(clk); 129 /* clock is optional */ 130 if (ret != -ENOENT) 131 goto err_clk; 132 } else { 133 ret = regmap_mmio_attach_clk(regmap, clk); 134 if (ret) 135 goto err_attach_clk; 136 } 137 138 reset = of_reset_control_get_optional_exclusive(np, NULL); 139 if (IS_ERR(reset)) { 140 ret = PTR_ERR(reset); 141 goto err_attach_clk; 142 } 143 144 ret = reset_control_deassert(reset); 145 if (ret) 146 goto err_reset; 147 } 148 149 syscon->regmap = regmap; 150 syscon->np = np; 151 152 list_add_tail(&syscon->list, &syscon_list); 153 154 return_ptr(syscon); 155 156 err_reset: 157 reset_control_put(reset); 158 err_attach_clk: 159 if (!IS_ERR(clk)) 160 clk_put(clk); 161 err_clk: 162 regmap_exit(regmap); 163 err_regmap: 164 iounmap(base); 165 return ERR_PTR(ret); 166 } 167 168 static struct regmap *device_node_get_regmap(struct device_node *np, 169 bool create_regmap, 170 bool check_res) 171 { 172 struct syscon *entry, *syscon = NULL; 173 174 mutex_lock(&syscon_list_lock); 175 176 list_for_each_entry(entry, &syscon_list, list) 177 if (entry->np == np) { 178 syscon = entry; 179 break; 180 } 181 182 if (!syscon) { 183 if (create_regmap) 184 syscon = of_syscon_register(np, check_res); 185 else 186 syscon = ERR_PTR(-EINVAL); 187 } 188 mutex_unlock(&syscon_list_lock); 189 190 if (IS_ERR(syscon)) 191 return ERR_CAST(syscon); 192 193 return syscon->regmap; 194 } 195 196 /** 197 * of_syscon_register_regmap() - Register regmap for specified device node 198 * @np: Device tree node 199 * @regmap: Pointer to regmap object 200 * 201 * Register an externally created regmap object with syscon for the specified 202 * device tree node. This regmap will then be returned to client drivers using 203 * the syscon_regmap_lookup_by_phandle() API. 204 * 205 * Return: 0 on success, negative error code on failure. 206 */ 207 int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap) 208 { 209 struct syscon *entry, *syscon = NULL; 210 int ret; 211 212 if (!np || !regmap) 213 return -EINVAL; 214 215 syscon = kzalloc(sizeof(*syscon), GFP_KERNEL); 216 if (!syscon) 217 return -ENOMEM; 218 219 /* check if syscon entry already exists */ 220 mutex_lock(&syscon_list_lock); 221 222 list_for_each_entry(entry, &syscon_list, list) 223 if (entry->np == np) { 224 ret = -EEXIST; 225 goto err_unlock; 226 } 227 228 syscon->regmap = regmap; 229 syscon->np = np; 230 231 /* register the regmap in syscon list */ 232 list_add_tail(&syscon->list, &syscon_list); 233 mutex_unlock(&syscon_list_lock); 234 235 return 0; 236 237 err_unlock: 238 mutex_unlock(&syscon_list_lock); 239 kfree(syscon); 240 return ret; 241 } 242 EXPORT_SYMBOL_GPL(of_syscon_register_regmap); 243 244 /** 245 * device_node_to_regmap() - Get or create a regmap for specified device node 246 * @np: Device tree node 247 * 248 * Get a regmap for the specified device node. If there's not an existing 249 * regmap, then one is instantiated. This function should not be used if the 250 * device node has a custom regmap driver or has resources (clocks, resets) to 251 * be managed. Use syscon_node_to_regmap() instead for those cases. 252 * 253 * Return: regmap ptr on success, negative error code on failure. 254 */ 255 struct regmap *device_node_to_regmap(struct device_node *np) 256 { 257 return device_node_get_regmap(np, true, false); 258 } 259 EXPORT_SYMBOL_GPL(device_node_to_regmap); 260 261 /** 262 * syscon_node_to_regmap() - Get or create a regmap for specified syscon device node 263 * @np: Device tree node 264 * 265 * Get a regmap for the specified device node. If there's not an existing 266 * regmap, then one is instantiated if the node is a generic "syscon". This 267 * function is safe to use for a syscon registered with 268 * of_syscon_register_regmap(). 269 * 270 * Return: regmap ptr on success, negative error code on failure. 271 */ 272 struct regmap *syscon_node_to_regmap(struct device_node *np) 273 { 274 return device_node_get_regmap(np, of_device_is_compatible(np, "syscon"), true); 275 } 276 EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 277 278 struct regmap *syscon_regmap_lookup_by_compatible(const char *s) 279 { 280 struct device_node *syscon_np; 281 struct regmap *regmap; 282 283 syscon_np = of_find_compatible_node(NULL, NULL, s); 284 if (!syscon_np) 285 return ERR_PTR(-ENODEV); 286 287 regmap = syscon_node_to_regmap(syscon_np); 288 of_node_put(syscon_np); 289 290 return regmap; 291 } 292 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 293 294 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, 295 const char *property) 296 { 297 struct device_node *syscon_np; 298 struct regmap *regmap; 299 300 if (property) 301 syscon_np = of_parse_phandle(np, property, 0); 302 else 303 syscon_np = np; 304 305 if (!syscon_np) 306 return ERR_PTR(-ENODEV); 307 308 regmap = syscon_node_to_regmap(syscon_np); 309 310 if (property) 311 of_node_put(syscon_np); 312 313 return regmap; 314 } 315 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); 316 317 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np, 318 const char *property, 319 int arg_count, 320 unsigned int *out_args) 321 { 322 struct device_node *syscon_np; 323 struct of_phandle_args args; 324 struct regmap *regmap; 325 unsigned int index; 326 int rc; 327 328 rc = of_parse_phandle_with_fixed_args(np, property, arg_count, 329 0, &args); 330 if (rc) 331 return ERR_PTR(rc); 332 333 syscon_np = args.np; 334 if (!syscon_np) 335 return ERR_PTR(-ENODEV); 336 337 regmap = syscon_node_to_regmap(syscon_np); 338 for (index = 0; index < arg_count; index++) 339 out_args[index] = args.args[index]; 340 of_node_put(syscon_np); 341 342 return regmap; 343 } 344 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args); 345 346 /* 347 * It behaves the same as syscon_regmap_lookup_by_phandle() except where 348 * there is no regmap phandle. In this case, instead of returning -ENODEV, 349 * the function returns NULL. 350 */ 351 struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np, 352 const char *property) 353 { 354 struct regmap *regmap; 355 356 regmap = syscon_regmap_lookup_by_phandle(np, property); 357 if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV) 358 return NULL; 359 360 return regmap; 361 } 362 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional); 363