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/of.h> 23 24 #include "clk.h" 25 26 static LIST_HEAD(clocks); 27 static DEFINE_MUTEX(clocks_mutex); 28 29 #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) 30 struct clk *of_clk_get(struct device_node *np, int index) 31 { 32 struct of_phandle_args clkspec; 33 struct clk *clk; 34 int rc; 35 36 if (index < 0) 37 return ERR_PTR(-EINVAL); 38 39 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index, 40 &clkspec); 41 if (rc) 42 return ERR_PTR(rc); 43 44 of_clk_lock(); 45 clk = __of_clk_get_from_provider(&clkspec); 46 47 if (!IS_ERR(clk) && !__clk_get(clk)) 48 clk = ERR_PTR(-ENOENT); 49 50 of_clk_unlock(); 51 of_node_put(clkspec.np); 52 return clk; 53 } 54 EXPORT_SYMBOL(of_clk_get); 55 56 /** 57 * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node 58 * @np: pointer to clock consumer node 59 * @name: name of consumer's clock input, or NULL for the first clock reference 60 * 61 * This function parses the clocks and clock-names properties, 62 * and uses them to look up the struct clk from the registered list of clock 63 * providers. 64 */ 65 struct clk *of_clk_get_by_name(struct device_node *np, const char *name) 66 { 67 struct clk *clk = ERR_PTR(-ENOENT); 68 69 /* Walk up the tree of devices looking for a clock that matches */ 70 while (np) { 71 int index = 0; 72 73 /* 74 * For named clocks, first look up the name in the 75 * "clock-names" property. If it cannot be found, then 76 * index will be an error code, and of_clk_get() will fail. 77 */ 78 if (name) 79 index = of_property_match_string(np, "clock-names", name); 80 clk = of_clk_get(np, index); 81 if (!IS_ERR(clk)) 82 break; 83 else if (name && index >= 0) { 84 pr_err("ERROR: could not get clock %s:%s(%i)\n", 85 np->full_name, name ? name : "", index); 86 return clk; 87 } 88 89 /* 90 * No matching clock found on this node. If the parent node 91 * has a "clock-ranges" property, then we can try one of its 92 * clocks. 93 */ 94 np = np->parent; 95 if (np && !of_get_property(np, "clock-ranges", NULL)) 96 break; 97 } 98 99 return clk; 100 } 101 EXPORT_SYMBOL(of_clk_get_by_name); 102 #endif 103 104 /* 105 * Find the correct struct clk for the device and connection ID. 106 * We do slightly fuzzy matching here: 107 * An entry with a NULL ID is assumed to be a wildcard. 108 * If an entry has a device ID, it must match 109 * If an entry has a connection ID, it must match 110 * Then we take the most specific entry - with the following 111 * order of precedence: dev+con > dev only > con only. 112 */ 113 static struct clk_lookup *clk_find(const char *dev_id, const char *con_id) 114 { 115 struct clk_lookup *p, *cl = NULL; 116 int match, best_found = 0, best_possible = 0; 117 118 if (dev_id) 119 best_possible += 2; 120 if (con_id) 121 best_possible += 1; 122 123 list_for_each_entry(p, &clocks, node) { 124 match = 0; 125 if (p->dev_id) { 126 if (!dev_id || strcmp(p->dev_id, dev_id)) 127 continue; 128 match += 2; 129 } 130 if (p->con_id) { 131 if (!con_id || strcmp(p->con_id, con_id)) 132 continue; 133 match += 1; 134 } 135 136 if (match > best_found) { 137 cl = p; 138 if (match != best_possible) 139 best_found = match; 140 else 141 break; 142 } 143 } 144 return cl; 145 } 146 147 struct clk *clk_get_sys(const char *dev_id, const char *con_id) 148 { 149 struct clk_lookup *cl; 150 151 mutex_lock(&clocks_mutex); 152 cl = clk_find(dev_id, con_id); 153 if (cl && !__clk_get(cl->clk)) 154 cl = NULL; 155 mutex_unlock(&clocks_mutex); 156 157 return cl ? cl->clk : ERR_PTR(-ENOENT); 158 } 159 EXPORT_SYMBOL(clk_get_sys); 160 161 struct clk *clk_get(struct device *dev, const char *con_id) 162 { 163 const char *dev_id = dev ? dev_name(dev) : NULL; 164 struct clk *clk; 165 166 if (dev) { 167 clk = of_clk_get_by_name(dev->of_node, con_id); 168 if (!IS_ERR(clk)) 169 return clk; 170 if (PTR_ERR(clk) == -EPROBE_DEFER) 171 return clk; 172 } 173 174 return clk_get_sys(dev_id, con_id); 175 } 176 EXPORT_SYMBOL(clk_get); 177 178 void clk_put(struct clk *clk) 179 { 180 __clk_put(clk); 181 } 182 EXPORT_SYMBOL(clk_put); 183 184 void clkdev_add(struct clk_lookup *cl) 185 { 186 mutex_lock(&clocks_mutex); 187 list_add_tail(&cl->node, &clocks); 188 mutex_unlock(&clocks_mutex); 189 } 190 EXPORT_SYMBOL(clkdev_add); 191 192 void __init clkdev_add_table(struct clk_lookup *cl, size_t num) 193 { 194 mutex_lock(&clocks_mutex); 195 while (num--) { 196 list_add_tail(&cl->node, &clocks); 197 cl++; 198 } 199 mutex_unlock(&clocks_mutex); 200 } 201 202 #define MAX_DEV_ID 20 203 #define MAX_CON_ID 16 204 205 struct clk_lookup_alloc { 206 struct clk_lookup cl; 207 char dev_id[MAX_DEV_ID]; 208 char con_id[MAX_CON_ID]; 209 }; 210 211 static struct clk_lookup * __init_refok 212 vclkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, 213 va_list ap) 214 { 215 struct clk_lookup_alloc *cla; 216 217 cla = __clkdev_alloc(sizeof(*cla)); 218 if (!cla) 219 return NULL; 220 221 cla->cl.clk = clk; 222 if (con_id) { 223 strlcpy(cla->con_id, con_id, sizeof(cla->con_id)); 224 cla->cl.con_id = cla->con_id; 225 } 226 227 if (dev_fmt) { 228 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap); 229 cla->cl.dev_id = cla->dev_id; 230 } 231 232 return &cla->cl; 233 } 234 235 struct clk_lookup * __init_refok 236 clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...) 237 { 238 struct clk_lookup *cl; 239 va_list ap; 240 241 va_start(ap, dev_fmt); 242 cl = vclkdev_alloc(clk, con_id, dev_fmt, ap); 243 va_end(ap); 244 245 return cl; 246 } 247 EXPORT_SYMBOL(clkdev_alloc); 248 249 int clk_add_alias(const char *alias, const char *alias_dev_name, char *id, 250 struct device *dev) 251 { 252 struct clk *r = clk_get(dev, id); 253 struct clk_lookup *l; 254 255 if (IS_ERR(r)) 256 return PTR_ERR(r); 257 258 l = clkdev_alloc(r, alias, alias_dev_name); 259 clk_put(r); 260 if (!l) 261 return -ENODEV; 262 clkdev_add(l); 263 return 0; 264 } 265 EXPORT_SYMBOL(clk_add_alias); 266 267 /* 268 * clkdev_drop - remove a clock dynamically allocated 269 */ 270 void clkdev_drop(struct clk_lookup *cl) 271 { 272 mutex_lock(&clocks_mutex); 273 list_del(&cl->node); 274 mutex_unlock(&clocks_mutex); 275 kfree(cl); 276 } 277 EXPORT_SYMBOL(clkdev_drop); 278 279 /** 280 * clk_register_clkdev - register one clock lookup for a struct clk 281 * @clk: struct clk to associate with all clk_lookups 282 * @con_id: connection ID string on device 283 * @dev_id: format string describing device name 284 * 285 * con_id or dev_id may be NULL as a wildcard, just as in the rest of 286 * clkdev. 287 * 288 * To make things easier for mass registration, we detect error clks 289 * from a previous clk_register() call, and return the error code for 290 * those. This is to permit this function to be called immediately 291 * after clk_register(). 292 */ 293 int clk_register_clkdev(struct clk *clk, const char *con_id, 294 const char *dev_fmt, ...) 295 { 296 struct clk_lookup *cl; 297 va_list ap; 298 299 if (IS_ERR(clk)) 300 return PTR_ERR(clk); 301 302 va_start(ap, dev_fmt); 303 cl = vclkdev_alloc(clk, con_id, dev_fmt, ap); 304 va_end(ap); 305 306 if (!cl) 307 return -ENOMEM; 308 309 clkdev_add(cl); 310 311 return 0; 312 } 313 314 /** 315 * clk_register_clkdevs - register a set of clk_lookup for a struct clk 316 * @clk: struct clk to associate with all clk_lookups 317 * @cl: array of clk_lookup structures with con_id and dev_id pre-initialized 318 * @num: number of clk_lookup structures to register 319 * 320 * To make things easier for mass registration, we detect error clks 321 * from a previous clk_register() call, and return the error code for 322 * those. This is to permit this function to be called immediately 323 * after clk_register(). 324 */ 325 int clk_register_clkdevs(struct clk *clk, struct clk_lookup *cl, size_t num) 326 { 327 unsigned i; 328 329 if (IS_ERR(clk)) 330 return PTR_ERR(clk); 331 332 for (i = 0; i < num; i++, cl++) { 333 cl->clk = clk; 334 clkdev_add(cl); 335 } 336 337 return 0; 338 } 339 EXPORT_SYMBOL(clk_register_clkdevs); 340