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 51 WARN_ON(!mutex_is_locked(&syscon_list_lock)); 52 53 struct syscon *syscon __free(kfree) = kzalloc(sizeof(*syscon), GFP_KERNEL); 54 if (!syscon) 55 return ERR_PTR(-ENOMEM); 56 57 if (of_address_to_resource(np, 0, &res)) 58 return ERR_PTR(-ENOMEM); 59 60 base = of_iomap(np, 0); 61 if (!base) 62 return ERR_PTR(-ENOMEM); 63 64 /* Parse the device's DT node for an endianness specification */ 65 if (of_property_read_bool(np, "big-endian")) 66 syscon_config.val_format_endian = REGMAP_ENDIAN_BIG; 67 else if (of_property_read_bool(np, "little-endian")) 68 syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE; 69 else if (of_property_read_bool(np, "native-endian")) 70 syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE; 71 72 /* 73 * search for reg-io-width property in DT. If it is not provided, 74 * default to 4 bytes. regmap_init_mmio will return an error if values 75 * are invalid so there is no need to check them here. 76 */ 77 ret = of_property_read_u32(np, "reg-io-width", ®_io_width); 78 if (ret) 79 reg_io_width = 4; 80 81 ret = of_hwspin_lock_get_id(np, 0); 82 if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) { 83 syscon_config.use_hwlock = true; 84 syscon_config.hwlock_id = ret; 85 syscon_config.hwlock_mode = HWLOCK_IRQSTATE; 86 } else if (ret < 0) { 87 switch (ret) { 88 case -ENOENT: 89 /* Ignore missing hwlock, it's optional. */ 90 break; 91 default: 92 pr_err("Failed to retrieve valid hwlock: %d\n", ret); 93 fallthrough; 94 case -EPROBE_DEFER: 95 goto err_regmap; 96 } 97 } 98 99 syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start); 100 if (!syscon_config.name) { 101 ret = -ENOMEM; 102 goto err_regmap; 103 } 104 syscon_config.reg_stride = reg_io_width; 105 syscon_config.val_bits = reg_io_width * 8; 106 syscon_config.max_register = resource_size(&res) - reg_io_width; 107 if (!syscon_config.max_register) 108 syscon_config.max_register_is_0 = true; 109 110 regmap = regmap_init_mmio(NULL, base, &syscon_config); 111 kfree(syscon_config.name); 112 if (IS_ERR(regmap)) { 113 pr_err("regmap init failed\n"); 114 ret = PTR_ERR(regmap); 115 goto err_regmap; 116 } 117 118 if (check_res) { 119 clk = of_clk_get(np, 0); 120 if (IS_ERR(clk)) { 121 ret = PTR_ERR(clk); 122 /* clock is optional */ 123 if (ret != -ENOENT) 124 goto err_clk; 125 } else { 126 ret = regmap_mmio_attach_clk(regmap, clk); 127 if (ret) 128 goto err_attach_clk; 129 } 130 131 reset = of_reset_control_get_optional_exclusive(np, NULL); 132 if (IS_ERR(reset)) { 133 ret = PTR_ERR(reset); 134 goto err_attach_clk; 135 } 136 137 ret = reset_control_deassert(reset); 138 if (ret) 139 goto err_reset; 140 } 141 142 syscon->regmap = regmap; 143 syscon->np = np; 144 145 list_add_tail(&syscon->list, &syscon_list); 146 147 return_ptr(syscon); 148 149 err_reset: 150 reset_control_put(reset); 151 err_attach_clk: 152 if (!IS_ERR(clk)) 153 clk_put(clk); 154 err_clk: 155 regmap_exit(regmap); 156 err_regmap: 157 iounmap(base); 158 return ERR_PTR(ret); 159 } 160 161 static struct regmap *device_node_get_regmap(struct device_node *np, 162 bool create_regmap, 163 bool check_res) 164 { 165 struct syscon *entry, *syscon = NULL; 166 167 mutex_lock(&syscon_list_lock); 168 169 list_for_each_entry(entry, &syscon_list, list) 170 if (entry->np == np) { 171 syscon = entry; 172 break; 173 } 174 175 if (!syscon) { 176 if (create_regmap) 177 syscon = of_syscon_register(np, check_res); 178 else 179 syscon = ERR_PTR(-EINVAL); 180 } 181 mutex_unlock(&syscon_list_lock); 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 mutex_lock(&syscon_list_lock); 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 mutex_unlock(&syscon_list_lock); 227 228 return 0; 229 230 err_unlock: 231 mutex_unlock(&syscon_list_lock); 232 kfree(syscon); 233 return ret; 234 } 235 EXPORT_SYMBOL_GPL(of_syscon_register_regmap); 236 237 /** 238 * device_node_to_regmap() - Get or create a regmap for specified device node 239 * @np: Device tree node 240 * 241 * Get a regmap for the specified device node. If there's not an existing 242 * regmap, then one is instantiated. This function should not be used if the 243 * device node has a custom regmap driver or has resources (clocks, resets) to 244 * be managed. Use syscon_node_to_regmap() instead for those cases. 245 * 246 * Return: regmap ptr on success, negative error code on failure. 247 */ 248 struct regmap *device_node_to_regmap(struct device_node *np) 249 { 250 return device_node_get_regmap(np, true, false); 251 } 252 EXPORT_SYMBOL_GPL(device_node_to_regmap); 253 254 /** 255 * syscon_node_to_regmap() - Get or create a regmap for specified syscon device node 256 * @np: Device tree node 257 * 258 * Get a regmap for the specified device node. If there's not an existing 259 * regmap, then one is instantiated if the node is a generic "syscon". This 260 * function is safe to use for a syscon registered with 261 * of_syscon_register_regmap(). 262 * 263 * Return: regmap ptr on success, negative error code on failure. 264 */ 265 struct regmap *syscon_node_to_regmap(struct device_node *np) 266 { 267 return device_node_get_regmap(np, of_device_is_compatible(np, "syscon"), true); 268 } 269 EXPORT_SYMBOL_GPL(syscon_node_to_regmap); 270 271 struct regmap *syscon_regmap_lookup_by_compatible(const char *s) 272 { 273 struct device_node *syscon_np; 274 struct regmap *regmap; 275 276 syscon_np = of_find_compatible_node(NULL, NULL, s); 277 if (!syscon_np) 278 return ERR_PTR(-ENODEV); 279 280 regmap = syscon_node_to_regmap(syscon_np); 281 of_node_put(syscon_np); 282 283 return regmap; 284 } 285 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); 286 287 struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, 288 const char *property) 289 { 290 struct device_node *syscon_np; 291 struct regmap *regmap; 292 293 if (property) 294 syscon_np = of_parse_phandle(np, property, 0); 295 else 296 syscon_np = np; 297 298 if (!syscon_np) 299 return ERR_PTR(-ENODEV); 300 301 regmap = syscon_node_to_regmap(syscon_np); 302 303 if (property) 304 of_node_put(syscon_np); 305 306 return regmap; 307 } 308 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); 309 310 struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np, 311 const char *property, 312 int arg_count, 313 unsigned int *out_args) 314 { 315 struct device_node *syscon_np; 316 struct of_phandle_args args; 317 struct regmap *regmap; 318 unsigned int index; 319 int rc; 320 321 rc = of_parse_phandle_with_fixed_args(np, property, arg_count, 322 0, &args); 323 if (rc) 324 return ERR_PTR(rc); 325 326 syscon_np = args.np; 327 if (!syscon_np) 328 return ERR_PTR(-ENODEV); 329 330 regmap = syscon_node_to_regmap(syscon_np); 331 for (index = 0; index < arg_count; index++) 332 out_args[index] = args.args[index]; 333 of_node_put(syscon_np); 334 335 return regmap; 336 } 337 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args); 338 339 /* 340 * It behaves the same as syscon_regmap_lookup_by_phandle() except where 341 * there is no regmap phandle. In this case, instead of returning -ENODEV, 342 * the function returns NULL. 343 */ 344 struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np, 345 const char *property) 346 { 347 struct regmap *regmap; 348 349 regmap = syscon_regmap_lookup_by_phandle(np, property); 350 if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV) 351 return NULL; 352 353 return regmap; 354 } 355 EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional); 356