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 32 static struct clk *__of_clk_get_by_clkspec(struct of_phandle_args *clkspec, 33 const char *dev_id, const char *con_id) 34 { 35 struct clk *clk; 36 37 if (!clkspec) 38 return ERR_PTR(-EINVAL); 39 40 of_clk_lock(); 41 clk = __of_clk_get_from_provider(clkspec, dev_id, con_id); 42 of_clk_unlock(); 43 return clk; 44 } 45 46 /** 47 * of_clk_get_by_clkspec() - Lookup a clock form a clock provider 48 * @clkspec: pointer to a clock specifier data structure 49 * 50 * This function looks up a struct clk from the registered list of clock 51 * providers, an input is a clock specifier data structure as returned 52 * from the of_parse_phandle_with_args() function call. 53 */ 54 struct clk *of_clk_get_by_clkspec(struct of_phandle_args *clkspec) 55 { 56 return __of_clk_get_by_clkspec(clkspec, NULL, __func__); 57 } 58 59 static struct clk *__of_clk_get(struct device_node *np, int index, 60 const char *dev_id, const char *con_id) 61 { 62 struct of_phandle_args clkspec; 63 struct clk *clk; 64 int rc; 65 66 if (index < 0) 67 return ERR_PTR(-EINVAL); 68 69 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index, 70 &clkspec); 71 if (rc) 72 return ERR_PTR(rc); 73 74 clk = __of_clk_get_by_clkspec(&clkspec, dev_id, con_id); 75 of_node_put(clkspec.np); 76 77 return clk; 78 } 79 80 struct clk *of_clk_get(struct device_node *np, int index) 81 { 82 return __of_clk_get(np, index, np->full_name, NULL); 83 } 84 EXPORT_SYMBOL(of_clk_get); 85 86 static struct clk *__of_clk_get_by_name(struct device_node *np, 87 const char *dev_id, 88 const char *name) 89 { 90 struct clk *clk = ERR_PTR(-ENOENT); 91 92 /* Walk up the tree of devices looking for a clock that matches */ 93 while (np) { 94 int index = 0; 95 96 /* 97 * For named clocks, first look up the name in the 98 * "clock-names" property. If it cannot be found, then 99 * index will be an error code, and of_clk_get() will fail. 100 */ 101 if (name) 102 index = of_property_match_string(np, "clock-names", name); 103 clk = __of_clk_get(np, index, dev_id, name); 104 if (!IS_ERR(clk)) { 105 break; 106 } else if (name && index >= 0) { 107 if (PTR_ERR(clk) != -EPROBE_DEFER) 108 pr_err("ERROR: could not get clock %s:%s(%i)\n", 109 np->full_name, name ? name : "", index); 110 return clk; 111 } 112 113 /* 114 * No matching clock found on this node. If the parent node 115 * has a "clock-ranges" property, then we can try one of its 116 * clocks. 117 */ 118 np = np->parent; 119 if (np && !of_get_property(np, "clock-ranges", NULL)) 120 break; 121 } 122 123 return clk; 124 } 125 126 /** 127 * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node 128 * @np: pointer to clock consumer node 129 * @name: name of consumer's clock input, or NULL for the first clock reference 130 * 131 * This function parses the clocks and clock-names properties, 132 * and uses them to look up the struct clk from the registered list of clock 133 * providers. 134 */ 135 struct clk *of_clk_get_by_name(struct device_node *np, const char *name) 136 { 137 if (!np) 138 return ERR_PTR(-ENOENT); 139 140 return __of_clk_get_by_name(np, np->full_name, name); 141 } 142 EXPORT_SYMBOL(of_clk_get_by_name); 143 144 #else /* defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) */ 145 146 static struct clk *__of_clk_get_by_name(struct device_node *np, 147 const char *dev_id, 148 const char *name) 149 { 150 return ERR_PTR(-ENOENT); 151 } 152 #endif 153 154 /* 155 * Find the correct struct clk for the device and connection ID. 156 * We do slightly fuzzy matching here: 157 * An entry with a NULL ID is assumed to be a wildcard. 158 * If an entry has a device ID, it must match 159 * If an entry has a connection ID, it must match 160 * Then we take the most specific entry - with the following 161 * order of precedence: dev+con > dev only > con only. 162 */ 163 static struct clk_lookup *clk_find(const char *dev_id, const char *con_id) 164 { 165 struct clk_lookup *p, *cl = NULL; 166 int match, best_found = 0, best_possible = 0; 167 168 if (dev_id) 169 best_possible += 2; 170 if (con_id) 171 best_possible += 1; 172 173 list_for_each_entry(p, &clocks, node) { 174 match = 0; 175 if (p->dev_id) { 176 if (!dev_id || strcmp(p->dev_id, dev_id)) 177 continue; 178 match += 2; 179 } 180 if (p->con_id) { 181 if (!con_id || strcmp(p->con_id, con_id)) 182 continue; 183 match += 1; 184 } 185 186 if (match > best_found) { 187 cl = p; 188 if (match != best_possible) 189 best_found = match; 190 else 191 break; 192 } 193 } 194 return cl; 195 } 196 197 struct clk *clk_get_sys(const char *dev_id, const char *con_id) 198 { 199 struct clk_lookup *cl; 200 struct clk *clk = NULL; 201 202 mutex_lock(&clocks_mutex); 203 204 cl = clk_find(dev_id, con_id); 205 if (!cl) 206 goto out; 207 208 clk = __clk_create_clk(__clk_get_hw(cl->clk), dev_id, con_id); 209 if (IS_ERR(clk)) 210 goto out; 211 212 if (!__clk_get(clk)) { 213 __clk_free_clk(clk); 214 cl = NULL; 215 goto out; 216 } 217 218 out: 219 mutex_unlock(&clocks_mutex); 220 221 return cl ? clk : ERR_PTR(-ENOENT); 222 } 223 EXPORT_SYMBOL(clk_get_sys); 224 225 struct clk *clk_get(struct device *dev, const char *con_id) 226 { 227 const char *dev_id = dev ? dev_name(dev) : NULL; 228 struct clk *clk; 229 230 if (dev) { 231 clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id); 232 if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER) 233 return clk; 234 } 235 236 return clk_get_sys(dev_id, con_id); 237 } 238 EXPORT_SYMBOL(clk_get); 239 240 void clk_put(struct clk *clk) 241 { 242 __clk_put(clk); 243 } 244 EXPORT_SYMBOL(clk_put); 245 246 void clkdev_add(struct clk_lookup *cl) 247 { 248 mutex_lock(&clocks_mutex); 249 list_add_tail(&cl->node, &clocks); 250 mutex_unlock(&clocks_mutex); 251 } 252 EXPORT_SYMBOL(clkdev_add); 253 254 void __init clkdev_add_table(struct clk_lookup *cl, size_t num) 255 { 256 mutex_lock(&clocks_mutex); 257 while (num--) { 258 list_add_tail(&cl->node, &clocks); 259 cl++; 260 } 261 mutex_unlock(&clocks_mutex); 262 } 263 264 #define MAX_DEV_ID 20 265 #define MAX_CON_ID 16 266 267 struct clk_lookup_alloc { 268 struct clk_lookup cl; 269 char dev_id[MAX_DEV_ID]; 270 char con_id[MAX_CON_ID]; 271 }; 272 273 static struct clk_lookup * __init_refok 274 vclkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, 275 va_list ap) 276 { 277 struct clk_lookup_alloc *cla; 278 279 cla = __clkdev_alloc(sizeof(*cla)); 280 if (!cla) 281 return NULL; 282 283 cla->cl.clk = clk; 284 if (con_id) { 285 strlcpy(cla->con_id, con_id, sizeof(cla->con_id)); 286 cla->cl.con_id = cla->con_id; 287 } 288 289 if (dev_fmt) { 290 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap); 291 cla->cl.dev_id = cla->dev_id; 292 } 293 294 return &cla->cl; 295 } 296 297 struct clk_lookup * __init_refok 298 clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...) 299 { 300 struct clk_lookup *cl; 301 va_list ap; 302 303 va_start(ap, dev_fmt); 304 cl = vclkdev_alloc(clk, con_id, dev_fmt, ap); 305 va_end(ap); 306 307 return cl; 308 } 309 EXPORT_SYMBOL(clkdev_alloc); 310 311 int clk_add_alias(const char *alias, const char *alias_dev_name, char *id, 312 struct device *dev) 313 { 314 struct clk *r = clk_get(dev, id); 315 struct clk_lookup *l; 316 317 if (IS_ERR(r)) 318 return PTR_ERR(r); 319 320 l = clkdev_alloc(r, alias, alias_dev_name); 321 clk_put(r); 322 if (!l) 323 return -ENODEV; 324 clkdev_add(l); 325 return 0; 326 } 327 EXPORT_SYMBOL(clk_add_alias); 328 329 /* 330 * clkdev_drop - remove a clock dynamically allocated 331 */ 332 void clkdev_drop(struct clk_lookup *cl) 333 { 334 mutex_lock(&clocks_mutex); 335 list_del(&cl->node); 336 mutex_unlock(&clocks_mutex); 337 kfree(cl); 338 } 339 EXPORT_SYMBOL(clkdev_drop); 340 341 /** 342 * clk_register_clkdev - register one clock lookup for a struct clk 343 * @clk: struct clk to associate with all clk_lookups 344 * @con_id: connection ID string on device 345 * @dev_id: format string describing device name 346 * 347 * con_id or dev_id may be NULL as a wildcard, just as in the rest of 348 * clkdev. 349 * 350 * To make things easier for mass registration, we detect error clks 351 * from a previous clk_register() call, and return the error code for 352 * those. This is to permit this function to be called immediately 353 * after clk_register(). 354 */ 355 int clk_register_clkdev(struct clk *clk, const char *con_id, 356 const char *dev_fmt, ...) 357 { 358 struct clk_lookup *cl; 359 va_list ap; 360 361 if (IS_ERR(clk)) 362 return PTR_ERR(clk); 363 364 va_start(ap, dev_fmt); 365 cl = vclkdev_alloc(clk, con_id, dev_fmt, ap); 366 va_end(ap); 367 368 if (!cl) 369 return -ENOMEM; 370 371 clkdev_add(cl); 372 373 return 0; 374 } 375 EXPORT_SYMBOL(clk_register_clkdev); 376 377 /** 378 * clk_register_clkdevs - register a set of clk_lookup for a struct clk 379 * @clk: struct clk to associate with all clk_lookups 380 * @cl: array of clk_lookup structures with con_id and dev_id pre-initialized 381 * @num: number of clk_lookup structures to register 382 * 383 * To make things easier for mass registration, we detect error clks 384 * from a previous clk_register() call, and return the error code for 385 * those. This is to permit this function to be called immediately 386 * after clk_register(). 387 */ 388 int clk_register_clkdevs(struct clk *clk, struct clk_lookup *cl, size_t num) 389 { 390 unsigned i; 391 392 if (IS_ERR(clk)) 393 return PTR_ERR(clk); 394 395 for (i = 0; i < num; i++, cl++) { 396 cl->clk = clk; 397 clkdev_add(cl); 398 } 399 400 return 0; 401 } 402 EXPORT_SYMBOL(clk_register_clkdevs); 403