1 /* 2 * drivers/clk/clkdev.c 3 * 4 * Copyright (C) 2008 Russell King. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * Helper for the clk API to assist looking up a struct clk. 11 */ 12 #include <linux/module.h> 13 #include <linux/kernel.h> 14 #include <linux/device.h> 15 #include <linux/list.h> 16 #include <linux/errno.h> 17 #include <linux/err.h> 18 #include <linux/string.h> 19 #include <linux/mutex.h> 20 #include <linux/clk.h> 21 #include <linux/clkdev.h> 22 #include <linux/clk-provider.h> 23 #include <linux/of.h> 24 25 #include "clk.h" 26 27 static LIST_HEAD(clocks); 28 static DEFINE_MUTEX(clocks_mutex); 29 30 #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) 31 static struct clk *__of_clk_get(struct device_node *np, int index, 32 const char *dev_id, const char *con_id) 33 { 34 struct of_phandle_args clkspec; 35 struct clk *clk; 36 int rc; 37 38 if (index < 0) 39 return ERR_PTR(-EINVAL); 40 41 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index, 42 &clkspec); 43 if (rc) 44 return ERR_PTR(rc); 45 46 clk = __of_clk_get_from_provider(&clkspec, dev_id, con_id); 47 of_node_put(clkspec.np); 48 49 return clk; 50 } 51 52 struct clk *of_clk_get(struct device_node *np, int index) 53 { 54 return __of_clk_get(np, index, np->full_name, NULL); 55 } 56 EXPORT_SYMBOL(of_clk_get); 57 58 static struct clk *__of_clk_get_by_name(struct device_node *np, 59 const char *dev_id, 60 const char *name) 61 { 62 struct clk *clk = ERR_PTR(-ENOENT); 63 64 /* Walk up the tree of devices looking for a clock that matches */ 65 while (np) { 66 int index = 0; 67 68 /* 69 * For named clocks, first look up the name in the 70 * "clock-names" property. If it cannot be found, then 71 * index will be an error code, and of_clk_get() will fail. 72 */ 73 if (name) 74 index = of_property_match_string(np, "clock-names", name); 75 clk = __of_clk_get(np, index, dev_id, name); 76 if (!IS_ERR(clk)) { 77 break; 78 } else if (name && index >= 0) { 79 if (PTR_ERR(clk) != -EPROBE_DEFER) 80 pr_err("ERROR: could not get clock %s:%s(%i)\n", 81 np->full_name, name ? name : "", index); 82 return clk; 83 } 84 85 /* 86 * No matching clock found on this node. If the parent node 87 * has a "clock-ranges" property, then we can try one of its 88 * clocks. 89 */ 90 np = np->parent; 91 if (np && !of_get_property(np, "clock-ranges", NULL)) 92 break; 93 } 94 95 return clk; 96 } 97 98 /** 99 * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node 100 * @np: pointer to clock consumer node 101 * @name: name of consumer's clock input, or NULL for the first clock reference 102 * 103 * This function parses the clocks and clock-names properties, 104 * and uses them to look up the struct clk from the registered list of clock 105 * providers. 106 */ 107 struct clk *of_clk_get_by_name(struct device_node *np, const char *name) 108 { 109 if (!np) 110 return ERR_PTR(-ENOENT); 111 112 return __of_clk_get_by_name(np, np->full_name, name); 113 } 114 EXPORT_SYMBOL(of_clk_get_by_name); 115 116 #else /* defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) */ 117 118 static struct clk *__of_clk_get_by_name(struct device_node *np, 119 const char *dev_id, 120 const char *name) 121 { 122 return ERR_PTR(-ENOENT); 123 } 124 #endif 125 126 /* 127 * Find the correct struct clk for the device and connection ID. 128 * We do slightly fuzzy matching here: 129 * An entry with a NULL ID is assumed to be a wildcard. 130 * If an entry has a device ID, it must match 131 * If an entry has a connection ID, it must match 132 * Then we take the most specific entry - with the following 133 * order of precedence: dev+con > dev only > con only. 134 */ 135 static struct clk_lookup *clk_find(const char *dev_id, const char *con_id) 136 { 137 struct clk_lookup *p, *cl = NULL; 138 int match, best_found = 0, best_possible = 0; 139 140 if (dev_id) 141 best_possible += 2; 142 if (con_id) 143 best_possible += 1; 144 145 list_for_each_entry(p, &clocks, node) { 146 match = 0; 147 if (p->dev_id) { 148 if (!dev_id || strcmp(p->dev_id, dev_id)) 149 continue; 150 match += 2; 151 } 152 if (p->con_id) { 153 if (!con_id || strcmp(p->con_id, con_id)) 154 continue; 155 match += 1; 156 } 157 158 if (match > best_found) { 159 cl = p; 160 if (match != best_possible) 161 best_found = match; 162 else 163 break; 164 } 165 } 166 return cl; 167 } 168 169 struct clk *clk_get_sys(const char *dev_id, const char *con_id) 170 { 171 struct clk_lookup *cl; 172 struct clk *clk = NULL; 173 174 mutex_lock(&clocks_mutex); 175 176 cl = clk_find(dev_id, con_id); 177 if (!cl) 178 goto out; 179 180 clk = __clk_create_clk(cl->clk_hw, dev_id, con_id); 181 if (IS_ERR(clk)) 182 goto out; 183 184 if (!__clk_get(clk)) { 185 __clk_free_clk(clk); 186 cl = NULL; 187 goto out; 188 } 189 190 out: 191 mutex_unlock(&clocks_mutex); 192 193 return cl ? clk : ERR_PTR(-ENOENT); 194 } 195 EXPORT_SYMBOL(clk_get_sys); 196 197 struct clk *clk_get(struct device *dev, const char *con_id) 198 { 199 const char *dev_id = dev ? dev_name(dev) : NULL; 200 struct clk *clk; 201 202 if (dev) { 203 clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id); 204 if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER) 205 return clk; 206 } 207 208 return clk_get_sys(dev_id, con_id); 209 } 210 EXPORT_SYMBOL(clk_get); 211 212 void clk_put(struct clk *clk) 213 { 214 __clk_put(clk); 215 } 216 EXPORT_SYMBOL(clk_put); 217 218 static void __clkdev_add(struct clk_lookup *cl) 219 { 220 mutex_lock(&clocks_mutex); 221 list_add_tail(&cl->node, &clocks); 222 mutex_unlock(&clocks_mutex); 223 } 224 225 void clkdev_add(struct clk_lookup *cl) 226 { 227 if (!cl->clk_hw) 228 cl->clk_hw = __clk_get_hw(cl->clk); 229 __clkdev_add(cl); 230 } 231 EXPORT_SYMBOL(clkdev_add); 232 233 void clkdev_add_table(struct clk_lookup *cl, size_t num) 234 { 235 mutex_lock(&clocks_mutex); 236 while (num--) { 237 cl->clk_hw = __clk_get_hw(cl->clk); 238 list_add_tail(&cl->node, &clocks); 239 cl++; 240 } 241 mutex_unlock(&clocks_mutex); 242 } 243 244 #define MAX_DEV_ID 20 245 #define MAX_CON_ID 16 246 247 struct clk_lookup_alloc { 248 struct clk_lookup cl; 249 char dev_id[MAX_DEV_ID]; 250 char con_id[MAX_CON_ID]; 251 }; 252 253 static struct clk_lookup * __init_refok 254 vclkdev_alloc(struct clk_hw *hw, const char *con_id, const char *dev_fmt, 255 va_list ap) 256 { 257 struct clk_lookup_alloc *cla; 258 259 cla = __clkdev_alloc(sizeof(*cla)); 260 if (!cla) 261 return NULL; 262 263 cla->cl.clk_hw = hw; 264 if (con_id) { 265 strlcpy(cla->con_id, con_id, sizeof(cla->con_id)); 266 cla->cl.con_id = cla->con_id; 267 } 268 269 if (dev_fmt) { 270 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap); 271 cla->cl.dev_id = cla->dev_id; 272 } 273 274 return &cla->cl; 275 } 276 277 static struct clk_lookup * 278 vclkdev_create(struct clk_hw *hw, const char *con_id, const char *dev_fmt, 279 va_list ap) 280 { 281 struct clk_lookup *cl; 282 283 cl = vclkdev_alloc(hw, con_id, dev_fmt, ap); 284 if (cl) 285 __clkdev_add(cl); 286 287 return cl; 288 } 289 290 struct clk_lookup * __init_refok 291 clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...) 292 { 293 struct clk_lookup *cl; 294 va_list ap; 295 296 va_start(ap, dev_fmt); 297 cl = vclkdev_alloc(__clk_get_hw(clk), con_id, dev_fmt, ap); 298 va_end(ap); 299 300 return cl; 301 } 302 EXPORT_SYMBOL(clkdev_alloc); 303 304 struct clk_lookup * 305 clkdev_hw_alloc(struct clk_hw *hw, const char *con_id, const char *dev_fmt, ...) 306 { 307 struct clk_lookup *cl; 308 va_list ap; 309 310 va_start(ap, dev_fmt); 311 cl = vclkdev_alloc(hw, con_id, dev_fmt, ap); 312 va_end(ap); 313 314 return cl; 315 } 316 EXPORT_SYMBOL(clkdev_hw_alloc); 317 318 /** 319 * clkdev_create - allocate and add a clkdev lookup structure 320 * @clk: struct clk to associate with all clk_lookups 321 * @con_id: connection ID string on device 322 * @dev_fmt: format string describing device name 323 * 324 * Returns a clk_lookup structure, which can be later unregistered and 325 * freed. 326 */ 327 struct clk_lookup *clkdev_create(struct clk *clk, const char *con_id, 328 const char *dev_fmt, ...) 329 { 330 struct clk_lookup *cl; 331 va_list ap; 332 333 va_start(ap, dev_fmt); 334 cl = vclkdev_create(__clk_get_hw(clk), con_id, dev_fmt, ap); 335 va_end(ap); 336 337 return cl; 338 } 339 EXPORT_SYMBOL_GPL(clkdev_create); 340 341 /** 342 * clkdev_hw_create - allocate and add a clkdev lookup structure 343 * @hw: struct clk_hw to associate with all clk_lookups 344 * @con_id: connection ID string on device 345 * @dev_fmt: format string describing device name 346 * 347 * Returns a clk_lookup structure, which can be later unregistered and 348 * freed. 349 */ 350 struct clk_lookup *clkdev_hw_create(struct clk_hw *hw, const char *con_id, 351 const char *dev_fmt, ...) 352 { 353 struct clk_lookup *cl; 354 va_list ap; 355 356 va_start(ap, dev_fmt); 357 cl = vclkdev_create(hw, con_id, dev_fmt, ap); 358 va_end(ap); 359 360 return cl; 361 } 362 EXPORT_SYMBOL_GPL(clkdev_hw_create); 363 364 int clk_add_alias(const char *alias, const char *alias_dev_name, 365 const char *con_id, struct device *dev) 366 { 367 struct clk *r = clk_get(dev, con_id); 368 struct clk_lookup *l; 369 370 if (IS_ERR(r)) 371 return PTR_ERR(r); 372 373 l = clkdev_create(r, alias, alias_dev_name ? "%s" : NULL, 374 alias_dev_name); 375 clk_put(r); 376 377 return l ? 0 : -ENODEV; 378 } 379 EXPORT_SYMBOL(clk_add_alias); 380 381 /* 382 * clkdev_drop - remove a clock dynamically allocated 383 */ 384 void clkdev_drop(struct clk_lookup *cl) 385 { 386 mutex_lock(&clocks_mutex); 387 list_del(&cl->node); 388 mutex_unlock(&clocks_mutex); 389 kfree(cl); 390 } 391 EXPORT_SYMBOL(clkdev_drop); 392 393 static struct clk_lookup *__clk_register_clkdev(struct clk_hw *hw, 394 const char *con_id, 395 const char *dev_id, ...) 396 { 397 struct clk_lookup *cl; 398 va_list ap; 399 400 va_start(ap, dev_id); 401 cl = vclkdev_create(hw, con_id, dev_id, ap); 402 va_end(ap); 403 404 return cl; 405 } 406 407 /** 408 * clk_register_clkdev - register one clock lookup for a struct clk 409 * @clk: struct clk to associate with all clk_lookups 410 * @con_id: connection ID string on device 411 * @dev_id: string describing device name 412 * 413 * con_id or dev_id may be NULL as a wildcard, just as in the rest of 414 * clkdev. 415 * 416 * To make things easier for mass registration, we detect error clks 417 * from a previous clk_register() call, and return the error code for 418 * those. This is to permit this function to be called immediately 419 * after clk_register(). 420 */ 421 int clk_register_clkdev(struct clk *clk, const char *con_id, 422 const char *dev_id) 423 { 424 struct clk_lookup *cl; 425 426 if (IS_ERR(clk)) 427 return PTR_ERR(clk); 428 429 /* 430 * Since dev_id can be NULL, and NULL is handled specially, we must 431 * pass it as either a NULL format string, or with "%s". 432 */ 433 if (dev_id) 434 cl = __clk_register_clkdev(__clk_get_hw(clk), con_id, "%s", 435 dev_id); 436 else 437 cl = __clk_register_clkdev(__clk_get_hw(clk), con_id, NULL); 438 439 return cl ? 0 : -ENOMEM; 440 } 441 EXPORT_SYMBOL(clk_register_clkdev); 442 443 /** 444 * clk_hw_register_clkdev - register one clock lookup for a struct clk_hw 445 * @hw: struct clk_hw to associate with all clk_lookups 446 * @con_id: connection ID string on device 447 * @dev_id: format string describing device name 448 * 449 * con_id or dev_id may be NULL as a wildcard, just as in the rest of 450 * clkdev. 451 */ 452 int clk_hw_register_clkdev(struct clk_hw *hw, const char *con_id, 453 const char *dev_id) 454 { 455 struct clk_lookup *cl; 456 457 /* 458 * Since dev_id can be NULL, and NULL is handled specially, we must 459 * pass it as either a NULL format string, or with "%s". 460 */ 461 if (dev_id) 462 cl = __clk_register_clkdev(hw, con_id, "%s", dev_id); 463 else 464 cl = __clk_register_clkdev(hw, con_id, NULL); 465 466 return cl ? 0 : -ENOMEM; 467 } 468 EXPORT_SYMBOL(clk_hw_register_clkdev); 469